JPH10158641A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably provide an organic luminescent (EL) element made by using a polymer, having high luminance, a high luminous efficiency, and the capability of drive at a low voltage and almost freed from the growth of dark spots even when stored for a long time. SOLUTION: This element has at least a luminescent layer between a pair of electrodes comprising an anode and a cathode at least either of which is transparent or translucent. The luminescent layer contains a polymer phosphor fluorescing in the solid state, comprising at least 50mol.%, based on the entire repeating units, repeating units each represented by the formula: -Ar-CR=CR'- [Ar is a 4-20 C arylene or heterocyclic compound group taking part in the conjugated bond; and R and R', which are independent of each other, are each hydrogen, a 1-20 C alkyl, a 6-20 C aryl, a 4-20 C heterocyclic compound group or cyano] and having a number-average molecular weight of 10<3> -10<7> (in terms of the polystyrene). At least part of the surface of the organic EL element is covered with a film made from a liquid crystal polyester resin composition containing 65.0-99.9wt.% liquid crystal polymer (A) and 35.0-0.1wt.% epoxy copolymer (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence device (hereinafter, sometimes referred to as an organic EL device).

[0002]

2. Description of the Related Art Inorganic electroluminescent elements (hereinafter sometimes referred to as inorganic EL elements) using an inorganic phosphor as a light emitting material are used, for example, in a planar light source as a backlight or a display device such as a flat panel display. However, a high voltage AC was required to emit light. In recent years, Tang et al. Have produced an organic EL device having a two-layer structure in which an organic fluorescent dye is used as a light emitting layer and an organic charge transporting compound used for an electrophotographic photoreceptor or the like is laminated (Japanese Patent Application Laid-Open No. 59-1984). -194393). Compared to inorganic EL elements, organic EL elements are characterized by low voltage driving, high luminance, and easy emission of many colors. Attempts have been reported [Japanese Journal of Applied Physics (Jpn. J. Appl. Phys.) Vol. 27, L2.
69 (1988)], [Journal of Applied Physics (J. Appl. Phys.) No. 6,
5, 3610 (1989)].

Heretofore, low-molecular-weight organic fluorescent dyes have been generally used as a material for the light-emitting layer.
Examples of the high molecular weight light emitting material include WO901148, JP-A-3-244630, and Applied Physics Letters (Appl. Phys. Le).
tt. Vol. 58, p. 1982 (1991). In the examples disclosed in WO 9013148, a poly (p-phenylenevinylene) thin film converted into a conjugated polymer is obtained by forming a soluble precursor on an electrode and performing a heat treatment. The disclosed EL element is disclosed. JP-A-3-244630 exemplifies a conjugated polymer which is soluble in a solvent itself and does not require heat treatment. Applied Physics Letters (Appl.
Phys. Lett. 58, 1982 (199)
1 year) also describes a polymer light-emitting material soluble in a solvent and an organic EL device prepared using the same. But,
The organic EL devices made using these materials do not always have a sufficiently high luminous efficiency, and have a low-luminance defect called a dark spot on the light-emitting surface during storage, deteriorating the display quality.

For an organic EL device using a low-molecular organic fluorescent dye, a single material such as indium and aluminum quinolinol complex or a co-deposited solid material such as indium or aluminum quinolinol complex, a silicone oil or a fluorinated carbon Organic EL devices using a liquid material such as such as a protective layer for electrodes are disclosed in JP-A-5-101892, JP-A-5-159882,
It is disclosed in JP-A-5-129080 and JP-A-5-41281.

However, in the organic EL device using a polymer which has been reported so far, a defect having a low brightness called a dark spot is generated on the light emitting surface during storage, so that
Improvements in display quality, prevention of deterioration in display quality during storage, generation of dark spots, and suppression of growth have been demanded. In order to suppress dark spots, a conventionally used method is to bond a glass and a substrate on which an anode and a luminescent material are provided with a resin mixed with a gap material such as silica, and apply nitrogen, argon, etc. to the cathode side of the device. A gas layer filled with an inert gas or a liquid layer such as silicone oil. However, in the device, there is a problem that the film thickness of the entire device is increased, and particularly when a polymer film is used as a base material, its characteristic fertility is lost by sealing. Further, the manufacturing process becomes difficult, and the manufacturing process cannot be performed at low cost, for example, the number of processes is increased.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-luminance, high-luminous-efficiency, low-drive-voltage organic EL using a polymer.
It is an object of the present invention to provide an inexpensive organic electroluminescent element which is an element and hardly grows dark spots even during long-term storage.

[0007]

In view of such circumstances, the present inventors have made intensive studies to improve the luminous efficiency of an organic EL device using a polymeric phosphor as a light emitting layer. By preserving the surface of the organic EL device having a light-emitting layer composed of a vinylene polymer fluorescent material with a film composed of a specific liquid crystal polyester resin composition, the storage characteristics of the organic EL device having high luminance and high luminous efficiency are improved. Then, they have found that an organic electroluminescent element in which most of the dark spots do not grow can be obtained, and have reached the present invention.

That is, the present invention relates to [1] an organic electroluminescence device having at least a light emitting layer between a pair of anodes and cathodes, at least one of which is transparent or translucent, wherein the light emitting layer is a solid-state fluorescent material; Wherein the repeating unit represented by the following general formula (1) comprises at least 50 mol% of all repeating units, and has a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ ; At least a part of the surface of the organic electroluminescent element has 65.0 to 99.9% by weight of the liquid crystal polyester of the component (A) and 35.0 to 0.1% of the copolymer having an epoxy group of the component (B). The present invention relates to an organic electroluminescence device coated with a film made of a liquid crystal polyester resin composition containing 1% by weight.

-Ar-CR = CR'- (1) [where Ar has 4 carbon atoms involved in a conjugated bond.
Represents an arylene group or a heterocyclic compound group consisting of at least 20 and at most 20, and R and R ′ each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms,
It represents a group selected from the group consisting of a heterocyclic compound having 4 to 20 carbon atoms and a cyano group. ]

Further, the present invention provides [2] an anode or a cathode, which is a transparent electrode made of a metal oxide formed on a polymer film, wherein the transparent electrode is located on the light emitting layer side with respect to the polymer film. The surface of the polymer film on the side opposite to the light emitting layer side, or the surface of the polymer film on the light emitting layer side and between the transparent electrode is formed of a gas barrier inorganic material and / or The present invention relates to the organic electroluminescence device according to [1], which is coated with a hard coat material. Furthermore, the present invention relates to [3] between the cathode and the light-emitting layer, between the layer containing the electron transporting compound adjacent to the light-emitting layer, and / or between the anode and the light-emitting layer. The organic electroluminescence device according to [1] or [2], further comprising a layer containing a hole transporting compound.

[0010] Further, the present invention provides that the (4) component (B) copolymer having an epoxy group contains 0.1 to 30% by weight of an unsaturated carboxylic acid glycidyl ester unit and / or an unsaturated glycidyl ether unit. [1] The organic electroluminescence device according to [1], Further, in the present invention, the liquid crystal polyester of the component (A) contains at least 30 mol% of the following repeating structural units in the entirety of the component (A). It relates to an organic electroluminescence element.

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[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the organic EL device of the present invention will be described in detail. The organic EL device of the present invention is an organic electroluminescence device having at least a light-emitting layer between a pair of anodes and cathodes, at least one of which is transparent or translucent, wherein the light-emitting layer has fluorescence in a solid state, The repeating unit represented by the general formula (1) is at least 50 mol% of all repeating units, and includes a polymeric fluorescent substance having a polystyrene equivalent number average molecular weight of 10 ³ to 10 ⁷ . Furthermore, the organic EL device of the present invention
At least a part of the surface of the organic EL element is a component (A)
Of the liquid crystal polyester of 65.0 to 99.9% by weight and the copolymer having an epoxy group of the component (B) of 35.0 to 95.0% by weight.
It is characterized by being covered with a film made of a liquid crystal polyester resin composition containing 0.1% by weight.
Next, the polymer phosphor used in the light emitting layer of the organic EL device of the present invention will be described. The polymeric fluorescent substance is a polymer containing the repeating unit represented by the general formula (1) in an amount of 50 mol% or more of all the repeating units. Although it depends on the structure of the repeating unit, it is preferable that the repeating unit represented by the general formula (1) accounts for 70% or more of all the repeating units. The polymeric fluorescent substance may be a divalent aromatic compound group or a derivative thereof, a divalent heterocyclic compound group or a derivative thereof, or a combination thereof as a repeating unit other than the repeating unit represented by the general formula (1). It may contain the resulting groups and the like. Further, a repeating unit represented by the general formula (1) or another repeating unit may be an ether group, an ester group,
They may be linked by a non-conjugated unit having an amide group, an imide group, or the like, or the repeating unit may include those non-conjugated portions.

In the polymeric fluorescent substance of the present invention, Ar in the general formula (1) is an arylene group or a heterocyclic compound group having 4 to 20 carbon atoms involved in a conjugate bond. And a divalent aromatic compound group or a derivative group thereof, a divalent heterocyclic compound group or a derivative group thereof, or a group obtained by combining them.

[0013]

Embedded image (R _{1 to} R ₉₂ each independently represent hydrogen, carbon number 1 to 2
0 alkyl, alkoxy and alkylthio groups,
An aryl group and an aryloxy group having 6 to 18 carbon atoms,
And a group selected from the group consisting of heterocyclic compound groups having 4 to 14 carbon atoms. )

Among them, phenylene group, substituted phenylene group, biphenylene group, substituted biphenylene group, naphthalenediyl group, substituted naphthalenediyl group, anthracene-9,10-diyl group, substituted anthracene-9,10-
Preferred are a diyl group, a pyridine-2,5-diyl group, a substituted pyridine-2,5-diyl group, a thienylene group or a substituted thienylene group. More preferably, phenylene group, biphenylene group, naphthalenediyl group, pyridine-2,5
-A diyl group or a thienylene group.

In the general formula (1), R and R 'are hydrogen or
In the case where is a substituent other than a cyano group,
Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group and an ethyl group.
, Propyl, butyl, pentyl, hexyl
Group, heptyl group, octyl group, decyl group, lauryl group
And methyl, ethyl, pentyl, hex
A sil group, a heptyl group and an octyl group are preferred. Aryl
As the group, a phenyl group, 4-C₁~ C₁₂Alkoxyv
Enyl group (C ₁~ C₁₂Indicates that it has 1 to 12 carbon atoms
You. Hereinafter, the same applies. ), 4-C₁~ C₁₂Alkyl
Examples include a phenyl group, a 1-naphthyl group and a 2-naphthyl group.
Is done.

From the viewpoint of solvent solubility, Ar in the general formula (1) is one or more of an alkyl group, an alkoxy group and an alkylthio group having 4 to 20 carbon atoms, an aryl group and an aryloxy group having 6 to 18 carbon atoms. And 4 to 14 carbon atoms
It is preferable to have a group selected from the heterocyclic compound groups of the above.

The following are examples of these substituents. Examples of the alkyl group having 4 to 20 carbon atoms include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, and a lauryl group. A pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable.
Examples of the alkoxy group having 4 to 20 carbon atoms include a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, and a lauryloxy group. , A heptyloxy group and an octyloxy group. Examples of the alkylthio group include a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decyloxy group, and a laurylthio group. A pentylthio group, a hexylthio group, a heptylthio group, and an octylthio group are preferable. As the aryl group,
Phenyl group, 4-C ₁ -C ₁₂ alkoxyphenyl group, 4
-C ₁ -C ₁₂ alkylphenyl group, 1-naphthyl group, 2
-Naphthyl group and the like. Examples of the aryloxy group include a phenoxy group. Examples of the heterocyclic compound group include a 2-thienyl group, a 2-pyrrolyl group, a 2-furyl group,
Examples thereof include a 2-, 3- or 4-pyridyl group. The number of these substituents varies depending on the molecular weight of the polymeric fluorescent substance and the structure of the repeating unit, but from the viewpoint of obtaining a polymeric fluorescent substance having high solubility, these substituents are one or more per 600 molecular weight. Is more preferable.

The polymer fluorescent substance used in the organic EL device of the present invention may be a random, block or graft copolymer, or a polymer having an intermediate structure between them, such as a block-like polymer. Or a random copolymer. From the viewpoint of obtaining a polymer fluorescent substance having a high fluorescence quantum yield, a random copolymer having block properties or a block or graft copolymer is preferable to a completely random copolymer. In addition, since the organic EL device of the present invention utilizes light emission from a thin film, a polymer fluorescent substance having fluorescence in a solid state is used.

As a good solvent for the polymeric fluorescent substance,
Examples include chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene and the like.
Although it depends on the structure and molecular weight of the polymeric fluorescent substance, it can be generally dissolved in these solvents in an amount of 0.1% by weight or more.

The polymeric fluorescent substance of the present invention has a molecular weight of 10 ³ to 10 ⁷ in terms of polystyrene, and the degree of polymerization thereof varies depending on the repeating structure and its ratio. In general, the total number of the repeating structures is preferably 4 to 10000, more preferably 5 to 3000, and particularly preferably 10 to 2000 from the viewpoint of film forming properties.

When a film is formed from a solution by using these organic solvent-soluble polymer fluorescent materials when manufacturing an organic EL device, it is only necessary to remove the solvent by drying after coating the solution. The same method can be applied to the case where a charge transporting material and a light emitting material are further mixed, which is very advantageous in manufacturing.

As a method for synthesizing the polymeric fluorescent substance used in the organic EL device of the present invention, for example, a dialdehyde compound in which two aldehyde groups are bonded to an arylene group and a methyl halide group which is bonded to two arylene groups are used. The Wittig reaction from a diphosphonium salt obtained from a compound and triphenylphosphine is exemplified. Another example of a synthesis method is a dehydrohalogenation method from a compound in which two methyl halide groups are bonded to an arylene group. Further, a sulfonium salt decomposition method for obtaining a polymeric fluorescent substance by heat treatment from an intermediate obtained by polymerizing a sulfonium salt of a compound having two arylene groups and two halogenated methyl groups with an alkali is exemplified. In any of the synthesis methods, a compound having a skeleton other than an arylene group is added as a monomer, and the structure of the repeating unit contained in the resulting polymeric fluorescent substance can be changed by changing the abundance. You may charge and copolymerize so that the repeating unit represented by Formula (1) may be 50 mol% or more, and may copolymerize. Among these, the method based on the Wittig reaction is preferable in terms of control of the reaction and yield.

More specifically, a method for synthesizing an arylenevinylene copolymer, which is one example of a polymeric fluorescent substance used in the organic EL device of the present invention, will be described. When a polymeric fluorescent substance is obtained by the Wittig reaction, first, a bis (methyl halide) compound, more specifically, for example, 2,2
5-Dioctyloxy-p-xylylenedibromide is reacted with triphenylphosphine in an N, N-dimethylformamide solvent to synthesize a phosphonium salt, which is then reacted with a dialdehyde compound, more specifically, for example, terephthalaldehyde. Is condensed using, for example, lithium ethoxide in ethyl alcohol to obtain a polymeric fluorescent substance containing a phenylenevinylene group and a 2,5-dioctyloxy-p-phenylenevinylene group. At this time, two or more kinds of diphosphonium salts and / or two or more kinds of dialdehyde compounds may be reacted to obtain a copolymer.

When these polymer fluorescent materials are used as a light emitting material of an organic EL device, their purity affects the light emitting characteristics. Therefore, after the synthesis, purification treatment such as reprecipitation purification, chromatographic separation, etc., may be required. preferable.

Next, a film made of a liquid crystal polyester resin composition used for an organic EL device, which is a feature of the present invention, will be described. Hereinafter, a film made of the liquid crystal polyester resin composition may be referred to as a protective layer. The liquid crystal polyester resin composition contains 65.0 to 99.9% by weight of the liquid crystal polyester of the component (A) and 35.0 to 0.1% by weight of the copolymer having an epoxy group of the component (B). . The liquid crystal polyester of the component (A) is a polyester called a thermotropic liquid crystal polymer.

Specific examples of the liquid crystal polyester resin composition include (1) a combination of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and an aromatic or aliphatic diol; (3) a mixture of an aromatic dicarboxylic acid and an aromatic or aliphatic diol; (4) a polyester obtained by reacting an aromatic hydroxycarboxylic acid with a polyester such as polyethylene terephthalate. One that forms an anisotropic melt at a temperature of 400 ° C. or lower is preferable. Incidentally, these aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids,
Instead of aromatic or aliphatic diols, their ester-forming derivatives may be used. Examples of the repeating structural unit of the liquid crystal polyester include, but are not limited to, the following.

The following are examples of the repeating structural unit derived from an aromatic dicarboxylic acid.

Embedded image

The following are examples of the repeating structural unit derived from the aromatic diol.

Embedded image

The following are examples of the repeating structural unit derived from the aromatic hydroxycarboxylic acid.

Embedded image

A liquid crystal polyester which is particularly preferred in view of the balance among heat resistance, mechanical properties, and processability contains a repeating structural unit represented by the above general formula (2).
Specifically, those having the following combinations of repeating structural units (I) to (VI) are exemplified.

[0031]

Embedded image

The liquid crystal polyesters (I), (II),
For (III) and (IV), for example,
JP-B-47-47870, JP-B-63-3888
JP, JP-B-63-3891, JP-B-56-1
No. 8016, for example. Of these, a combination of (I) and (II) is more preferable.

In the field where high heat resistance is required in the liquid crystal polyester resin composition of the present invention, the liquid crystal polyester of the component (A) contains 30 to 80 mol% of the following repeating unit (a '), A liquid crystal polyester in which (b ') is 0 to 10 mol%, the repeating unit (c') is 10 to 25 mol%, and the repeating unit (d ') is 10 to 35 mol% is preferably used.

[0034]

Embedded image (In the formula, Ar ′ is a divalent aromatic group.)

In the field of the liquid crystal polyester resin composition used in the present invention, from the viewpoint of environmental problems, easy disposal such as incineration after use is required. Among them, particularly preferred is a liquid crystal polyester formed of a combination consisting of only carbon, hydrogen and oxygen.

The component (B) of the liquid crystal polyester resin composition used in the present invention is a copolymer having an epoxy group. The copolymer may be a thermoplastic resin or rubber, or a mixture of a thermoplastic resin and rubber. In the liquid crystal polyester resin composition, it is preferable that the liquid crystal polyester of the component (A) forms a continuous phase and the copolymer having an epoxy group of the component (B) forms a dispersed phase. The moldability of the liquid crystal polyester resin composition is better than that of the liquid crystal polyester alone. Although the reason for this is not necessarily clear, it is considered that the carboxylic acid at the terminal of the liquid crystal polyester of the component (A) and the epoxy group of the component (B) reacted to change the temperature dependence of the melt viscosity.

Among the substituents having an epoxy group, a glycidyl group is preferred. Examples of the monomer containing a glycidyl group include unsaturated carboxylic acid glycidyl ester and / or
Alternatively, unsaturated carboxylic acid glycidyl ether is preferably used.

The unsaturated carboxylic acid glycidyl ester unit has the general formula

Embedded image (Q ₁ is a 2-1 carbon atom having an ethylenically unsaturated bond.
3 hydrocarbon groups. ).

The compound providing an unsaturated carboxylic acid glycidyl ether unit has the general formula

Embedded image (Q ₂ is a C 2 to C 1 having an ethylenically unsaturated bond.
8 is a hydrocarbon group, Y is, -CH ₂ O-or

[0040]

Embedded image It is. )

Specifically, examples of the unsaturated glycidyl carboxylate include glycidyl acrylate, glycidyl methacrylate, glycidyl itaconate, triglycidyl butenetricarboxylate, and p-glycidyl ester.
-Styrene carboxylic acid glycidyl ester and the like. Examples of the unsaturated carboxylic acid glycidyl ether include vinyl glycidyl ether, allyl glycidyl ether, 2-methylallyl glycidyl ether, methacryl glycidyl ether, and styrene-p-glycidyl ether.

Further, as a specific example of the copolymer (B) having an epoxy group in the present invention, as the thermoplastic resin, (a) 50 to 99.9% by weight of ethylene unit;
(B) When the content of unsaturated glycidyl carboxylate ester units and / or unsaturated glycidyl ether units is 0.
An epoxy group-containing ethylene copolymer comprising 1 to 50% by weight, preferably 0.5 to 20% by weight can be mentioned. Further, as a specific example of the copolymer (B) having an epoxy group in the present invention, as the thermoplastic resin,
(A) 50 to 99.89% by weight of ethylene unit,
(B) When the content of unsaturated glycidyl carboxylate ester units and / or unsaturated glycidyl ether units is 0.
1 to 49.99% by weight, preferably 0.5 to 20% by weight;
An epoxy group-containing ethylene copolymer comprising from 01 to 49.9% by weight can be mentioned.

Examples of the ethylenically unsaturated ester compound (c) include vinyl carboxylate such as vinyl acetate, vinyl propionate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate. Esters, α, β-unsaturated carboxylic acid alkyl esters, and the like. Particularly, vinyl acetate, methyl acrylate and ethyl acrylate are preferred.

The epoxy group-containing ethylene copolymer (B) used in the present invention includes, for example, a copolymer composed of ethylene units and glycidyl methacrylate units, and a copolymer composed of ethylene units, glycidyl methacrylate units and methyl acrylate units. And copolymers composed of ethylene units, glycidyl methacrylate units and ethyl acrylate units, and copolymers composed of ethylene units, glycidyl methacrylate units and vinyl acetate units.

The melt index of the epoxy group-containing ethylene copolymer (B) [hereinafter may be referred to as MFR. This measurement was performed according to JIS K6760 (190 ° C,
2.16 kg load). Is preferably 0.5 to
100 g / 10 min, more preferably 2 to 50 g / 10
Minutes. The melt index may be out of this range. However, if the melt index exceeds 100 g / 10 minutes, it is not preferable from the viewpoint of mechanical properties of the composition, and if the melt index is less than 0.5 g / 10 minutes, the component (A) ) Is inferior in compatibility with the liquid crystal polyester. The epoxy group-containing ethylene copolymer (B) preferably has a flexural rigidity of 1
0 to 1800 kg / cm ² , more preferably 20 to 1
300 kg / cm ² is used. If the flexural rigidity is out of this range, the film forming processability of the composition may be insufficient or the mechanical properties of the film may be insufficient, which is not preferable.

The epoxy group-containing ethylene copolymer (B)
Is usually prepared by reacting an unsaturated epoxy compound and ethylene in the presence of a radical generator at 500 to 4000 atm, 100 to 300 atm.
It is produced by a method of copolymerizing at a temperature of ° C in the presence or absence of a suitable solvent or chain transfer agent. It can also be produced by a method in which an unsaturated epoxy compound and a radical generator are mixed with polyethylene and melt-grafted and copolymerized in an extruder.

Further, specific examples of the case where the copolymer (B) having an epoxy group in the present invention is a rubber include:
(Meth) acrylic acid ester-ethylene- (unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber can be exemplified. Preferably, the (meth) acrylate unit is 40 to 9
6.9% by weight, more preferably 50 to 70% by weight, ethylene unit 3 to 50% by weight, more preferably 10 to 10% by weight.
49.5% by weight, 0.1 to 10% by weight of unsaturated glycidyl ester unit and / or unsaturated glycidyl ether unit, and more preferably 0.5 to 10% by weight.
20% by weight. When the (meth) acrylate of the copolymer rubber is less than 40% by weight, the rubber elasticity decreases, the effect of improving the impact resistance of the composition is reduced, and the (meth) acrylate is 96. If the content is 9% by weight or more, the embrittlement point of the copolymer rubber becomes high, and the mechanical properties of the composition at low temperature may be undesirably reduced.

Here, the (meth) acrylate is
An ester obtained from acrylic acid or methacrylic acid and an alcohol. Alcohols have 1 carbon atom
~ 8 alcohols are preferred. Specific examples of (meth) acrylates include methyl acrylate, methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, ter
Examples thereof include t-butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. As the (meth) acrylic acid ester, one kind may be used alone, or two or more kinds may be used in combination.

The copolymer rubber has a Mooney viscosity of 3 to 3
0 is preferable, and 4 to 25 are more preferable. The Mooney viscosity referred to herein is JIS K6300.
Refers to the value measured using a large rotor at 100 ° C. according to

The copolymer rubber can be produced by a usual method, for example, bulk polymerization, emulsion polymerization, solution polymerization or the like using a free radical initiator. Typical polymerization methods are described in JP-B-46-45085 and JP-B-6-45085.
According to the method described in 1-127709 and the like,
Pressure of 5 in the presence of a free radical generating polymerization initiator
It can be manufactured under the conditions of at least 00 kg / cm ² and a temperature of 40 to 300 ° C.

The copolymer rubber is vulcanized as required, and can be used as a vulcanized rubber. The vulcanization of the (meth) acrylic acid ester-ethylene- (unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber is performed by multifunctional organic acids, polyfunctional amine compounds, imidazole compounds, etc. However, the present invention is not limited to these.

The ratio of component (A) to component (B) in the liquid crystal polyester resin composition used in the present invention is such that component (A) is 65.0 to 99.9% by weight, preferably 70.
0 to 98.0% by weight, component (B) is 35.0 to 0.1% by weight, preferably 30.0 to 2.0% by weight. If the content of the component (A) is less than 65.0% by weight, the film forming processability is insufficient, and the gas barrier properties and the tensile strength of the film obtained from the composition are undesirably reduced.
If the content of the component (A) exceeds 99.9% by weight, the effect of improving the anisotropy of the tensile strength of the film obtained from the composition may not be sufficient, which is not preferable.

Further, the components (A) and (B) in the liquid crystal polyester resin composition used in the present invention can be freely changed in combination within the above range depending on the use. However, from the viewpoint of environmental problems, carbon, oxygen, A combination consisting only of hydrogen is preferably used.

The method for producing the liquid crystal polyester resin composition of the present invention is not particularly limited, and a known method can be used. For example, mixing each component in a solution state,
Examples of the method include evaporating the solvent or precipitating the solvent. From an industrial point of view, a method of kneading each component in a molten state is preferred. For the melt kneading, kneading apparatuses such as a single-screw or twin-screw extruder and various kneaders which are generally used can be used. In particular, a biaxial high kneader is preferred. In the melt kneading, the cylinder set temperature of the kneading apparatus is determined depending on the temperature at which the liquid crystal polyester is melted, but is preferably in the range of 200 to 360 ° C, more preferably 230 to 340 ° C.

At the time of kneading, each component may be previously mixed uniformly with a device such as a tumbler or a Henschel mixer, or a method in which the mixing is omitted and separately supplied to the kneading device separately may be used. it can.

In the production of the liquid crystal polyester resin composition film in the present invention, the liquid crystal polyester resin composition obtained by the above-mentioned method is melt-kneaded by an extruder, and then a die is formed.
This is done by taking up the molten resin extruded through. Without obtaining the kneading process in advance, dry blending each component at the time of molding and kneading during the melt processing operation to obtain a resin composition,
Direct molded products can also be obtained. The base (die)
Usually, a T die or an annular slit die (hereinafter sometimes referred to as an inflation die) can be used.

In the case of film forming using a T-die, the liquid crystal polyester resin composition melt-kneaded by an extruder is usually turned into a sheet-like melt through a downward T-die, and then passed through a pressure roll to a take-off device in the longitudinal direction. Picked up at A biaxially stretched film can be obtained from a sheet-like melt extruded from a T-die using a biaxial stretching machine, a tenter or the like.

The slit interval of the T die is 0.2 mm to 1.0 mm.
5 mm is preferable, and 1 μm to 1000 mm by stretching.
A film having a thickness of 10 μm to 15 μm can be obtained.
A 0 μm film is preferably used for practical use.

In the case of inflation molding using an annular slit die, the liquid crystal polyester resin composition is supplied to a melt-kneading extruder equipped with an annular slit die, and a cylindrical resin composition melt is fed upward from the annular slit die. Alternatively, when the melt is extruded downward, it is stretched by enclosing a gas inside and being drawn in a direction in which the melt is extruded, thereby obtaining a cylindrical film. In the case of this film forming method,
For example, a film having an arbitrary thickness can be obtained by changing the amount of enclosed gas and the speed of taking out the gas. The interval between the annular slits is usually 0.1 mm to 5 mm, preferably 0.5 m
m ~ 2mm, the diameter of the annular slit is usually 20mm ~ 5
00 mm, preferably 50 mm to 300 mm.

The thickness of the liquid crystal polyester resin composition film in inflation film formation is 5 μm to 1000 μm.
It can be controlled in the range of 10 μm to 15 μm.
Those having a thickness of 0 μm are preferably used. In any case, the film forming temperature is preferably in a range from a temperature at which the liquid crystal polyester resin composition used in the present invention starts to melt to a temperature 60 ° C. higher than the temperature.

Next, a typical method for fabricating the organic EL device of the present invention will be described. In a pair of electrodes composed of an anode and a cathode, examples of the transparent or translucent electrode include a transparent or translucent electrode formed on a substrate such as glass or a transparent polymer film. As a material for the anode, a conductive metal oxide film, a translucent metal thin film, or the like is used. Specifically, as a material of the anode, a film (NESA or the like) formed using a conductive glass made of indium tin oxide (ITO), tin oxide, or the like, zinc sulfide, Au, Pt, Ag, Cu And the like. As a manufacturing method, a vacuum evaporation method, a sputtering method,
A plating method or the like is used.

The organic EL device of the present invention includes a device having a hole transporting layer containing a hole transporting compound adjacent to the light emitting layer between the anode and the light emitting layer. When a hole transport layer is formed on the anode, a known hole transport compound can be used for the hole transport layer. Examples of the hole-transporting compound include low-molecular pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, and the like, high-molecular poly (N-vinylcarbazole), polyaniline or a derivative thereof, polythiophene or a derivative thereof, Examples thereof include poly (p-phenylenevinylene) or a derivative thereof, and poly (2,5-thienylenevinylene) or a derivative thereof. The low molecular weight hole transporting compound may be used alone, or may be used as a mixture with a transparent high molecular weight compound. Examples of the polymer compound used include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane. As a solvent for dissolving the hole transport layer in the case of applying using a solution, it is preferable that the solvent has low solubility with respect to the polymeric fluorescent substance of the light emitting layer.

As a method for forming the hole transporting layer, a spin coating method, a casting method, a dipping method, a bar coating method, a roll coating method, etc., using a melt, solution or mixed solution of the hole transporting compound. Coating method, or spin coating method, casting method, dipping method, bar coating method, roll coating method of a solution or a mixed solution after mixing and dispersing a binder resin and the hole transporting compound in a solution state or a molten state and then dispersing the mixture. An application method by a method or the like is exemplified. Among these methods, a coating method using a binder resin is preferable. The binder resin to be mixed is not particularly limited, but is preferably one that does not extremely impair the hole transporting property, and one that does not strongly absorb visible light is preferably used. The thickness of the hole transport layer is preferably 0.5 nm to 10 μm, more preferably 1 nm.
m to 1 μm. In order to increase the luminous efficiency by increasing the current density, the thickness is more preferably 10 to 800 nm.

Next, a light emitting material or a light emitting layer containing a light emitting material and a charge transporting material is formed. As a method for forming the light emitting layer, a vacuum evaporation method from a powder state of these materials, or a spin coating method, a casting method, a dipping method, a bar coating method, a roll coating method using a melt, a solution or a mixture of these materials is used. Coating methods such as a coating method. When a low molecular compound is used among these methods, a vacuum evaporation method is preferable. When a polymer compound is used, a coating method such as a spin coating method, a casting method, a dipping method, a bar coating method, or a roll coating method using a solution or a mixed solution is preferable. The thickness of the light emitting layer is preferably 0.5 nm to 10 μm.
m, more preferably 1 nm to 1 μm. In order to increase luminous efficiency by increasing current density, it is more preferable that
0 to 500 nm. When the hole transport layer and the light-emitting layer are thinned by a coating method, the solvent is removed, so that after the hole transport layer is formed and / or after the light-emitting layer is formed,
Under reduced pressure or an inert atmosphere, preferably 30 to 30
It is preferable to heat and dry at a temperature of 0 ° C, more preferably 60 to 200 ° C.

The organic EL device of the present invention includes a device having a layer containing an electron-transporting compound between the cathode and the light-emitting layer, adjacent to the light-emitting layer. Further, as the organic EL device of the present invention, between the cathode and the light emitting layer, a layer containing an electron transporting compound adjacent to the light emitting layer, and between the anode and the light emitting layer, adjacent to the light emitting layer. And a layer containing a hole transporting compound. When an electron transporting layer is further laminated on the light emitting layer, it is preferable to form an electron transporting layer using a known electron transporting compound thereon after providing the light emitting layer by the above-described film forming method. . The electron transporting compound is preferably an oxadiazole derivative, benzoquinone or a derivative thereof, anthraquinone or a derivative thereof, or a metal complex of 8-hydroxyquinoline or a derivative thereof, and particularly, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,3
4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum are preferred.

After mixing and dispersing the polymer compound and the charge transporting material in a solution state or a molten state, a microgravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating, A coating method, a screen printing method, a flexographic printing method, and an offset printing method can be used. As the polymer compound to be mixed, those which do not extremely inhibit charge transport are preferable, and those which do not strongly absorb visible light are suitably used. Examples of the polymer include poly (N-vinylcarbazole), polyaniline or a derivative thereof, polythiophene or a derivative thereof, poly (p-phenylenevinylene) or a derivative thereof, poly (2,5-thienylenevinylene) or a derivative thereof, and polycarbonate. , Polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, or polysiloxane. The film forming method of the electron transport layer is not particularly limited, but a vacuum deposition method from a powder state, or a spin coating method after dissolving in a solution, a casting method, a dipping method,
Coating methods such as bar coating method and roll coating method, or spin coating method after mixing and dispersing a binder resin and a charge transport material in a solution state or a molten state, casting method, dipping method, bar coating method, roll coating method A coating method such as a coating method can be used. The thickness of the electron transport layer is required to be at least such that pinholes do not occur. However, if the thickness is too large, the resistance of the element increases and a high drive voltage is required, which is not preferable. Therefore, the thickness of the charge transport layer is preferably 0.5 nm to 10 nm.
μm, more preferably 1 nm to 1 μm, particularly preferably 5 to 200 nm.

In order to form a light emitting pattern or to make etching for forming an electrode unnecessary,
It is preferable to provide an insulating layer before or after forming these organic layers. Examples of the material of the insulating layer include a photocurable resin, a thermosetting resin, an organic material such as polycarbonate and polyethersulfone, and an inorganic material such as Al ₂ O ₃ and SiO ₂ , which are formed during continuous coating. When it is necessary to apply, a photocurable resin or a thermosetting resin that can be formed by coating and curing in a short time is more preferable.

Next, an electrode is provided on the light emitting layer or the electron transport layer. This electrode becomes an electron injection cathode. As a material of the cathode used in the present invention, a material having a small ionization energy is preferable. For example, aluminum, indium, magnesium, calcium, lithium, magnesium-silver alloy, magnesium-indium alloy, lithium-aluminum alloy, lithium-silver alloy, lithium-indium alloy, calcium-aluminum alloy, graphite thin film and the like are used. As a method for manufacturing the cathode, a vacuum evaporation method, a sputtering method, a lamination method in which a metal thin film is thermocompressed, or the like is used. After making the cathode,
A layer for protecting this may be provided. The layer is not particularly limited as long as it does not affect the EL characteristics, but is not limited to CaO, ZnO, MgO, GeO, SiO ₂ , Al
Oxide such as ₂ O ₃ , fluoride such as MgF ₂ , Al
Nitrides such as N and BN, organic compounds containing fluorine, polyvinyl chloride, polyethylene terephthalate,
Examples thereof include polymer materials such as polyolefin.

Next, at least a part of the surface of the organic EL device, which is a feature of the organic EL device of the present invention, comprises 65.0 to 99.9% by weight of the liquid crystal polyester of the component (A) and the component (A). The fact that the film is covered with a film made of a liquid crystal polyester resin composition containing 35.0 to 0.1% by weight of the copolymer having an epoxy group (B) will be described. The organic EL device of the present invention is characterized in that at least a part of its surface is covered with a film made of the liquid crystal polyester resin composition. The proportion of the portion covered by the film is preferably large, and the entire surface of the organic EL element may be covered. Since the surface of the organic EL element has improved storage characteristics, it is preferable that the surface is adhered and covered with the film. Examples of a method of bonding the film to the surface of the organic EL element include a method of bonding using a photocurable resin or a thermosetting resin, and a thermocompression bonding method.

Next, a method of bonding using the photocurable resin or the thermosetting resin will be described. The photocurable resin and the thermosetting resin are not particularly limited as long as they do not affect the EL characteristics of the obtained organic EL device.
A resin having low water and oxygen permeability is preferable. In particular,
Examples of the photocurable resin include an acrylate resin and a fluorine-containing acrylate resin.
Epoxy resins and fluorinated epoxy resins are exemplified. In the case of bonding with the photo-curable resin or the thermosetting resin, the substrate to be used is not limited as long as it is a substrate with a transparent conductive film. It is preferable that the organic layer is removed and the substrate and the curable resin are in direct contact. Further, the bonded portion of the base material may be treated with a silane coupling agent in order to enhance the adhesiveness with the resin. Further, a space filled with a gas having a low water content such as an inert gas such as nitrogen or argon may be provided between the base material and the film made of the liquid crystal polyester resin composition. The substrate may be in direct contact with the substrate. Further, a water-absorbing resin or an oxygen scavenger may be inserted between the substrate and the film. When a low molecular compound is used for the organic layer, the curing agent of the thermosetting resin and the low molecular compound may react or dissolve. In that case, it is preferable to provide a space between the substrate and the film, the space being filled with an inert gas having a small water content, such as nitrogen or argon. FIG. 1 shows an example in which a substrate and a film made of a liquid crystal polyester resin composition are in close contact with each other. FIG. 2 shows an example in which an inert gas is filled between the substrate and the film made of the liquid crystal polyester resin composition. Here, the organic layer 7 indicates a light emitting layer or a light emitting layer and a hole transporting layer or an electron transporting layer.

Next, when using the thermocompression bonding method,
The substrate in the organic EL device is not limited, but a polymer film is preferable. In the case of thermocompression bonding, it is preferable to use a laminator. Thermocompression bonding temperature is 50 ℃ or more and 200
C. or less, more preferably 100.degree. C. or more and 150.degree. C. or less. When a polymer film is used for the substrate, it is preferable to use a material having low permeability to water, oxygen, or the like, that is, a material having high barrier properties.
The substrate is preferably coated with an inorganic material and / or a hard coat agent. That is, in one embodiment of the organic EL device of the present invention, the anode or the cathode is a transparent electrode made of a metal oxide formed on a polymer film,
The transparent electrode is disposed on the light emitting layer side with respect to the polymer film, and the surface of the polymer film opposite to the light emitting layer side is covered with a gas barrier inorganic material and / or a hard coat material. It becomes. In one embodiment of the organic EL device of the present invention, the anode or the cathode is a transparent electrode made of a metal oxide formed on a polymer film,
The transparent electrode is disposed on the light emitting layer side with respect to the polymer film, and the surface between the light emitting layer and the transparent electrode of the polymer film is formed of a gas barrier inorganic material and / or hard coat. It is covered with a material. Examples of the inorganic material include aluminum, titanium, nickel, vanadium and other metal materials that form a dense passivation layer on the surface, and oxides with high barrier properties such as water and oxygen such as SiO ₂ and Al ₂ O _3. You. The hard coating agent is not particularly limited, and examples thereof include an acrylate resin having a high barrier property such as water and oxygen.

In the present invention, known light-emitting materials that can be used together with the polymeric fluorescent substance include, for example, naphthalene derivatives, anthracene or derivatives thereof, perylene or derivatives thereof, polymethine-based, xanthene-based, coumarin-based, and cyanine-based dyes. , A metal complex of 8-hydroxyquinoline or a derivative thereof, an aromatic amine, tetraphenylcyclopentadiene or a derivative thereof, or tetraphenylbutadiene or a derivative thereof can be used. More specifically, for example,
Known ones such as those described in JP-A-51781 and JP-A-59-194393 can be used. Further, a light emitting material described below other than the polymeric fluorescent substance may be mixed and used in the light emitting layer. Further, a layer in which the polymeric fluorescent substance and / or the charge transporting material is dispersed in a polymeric compound may be used.

In the present invention, known charge transporting materials, that is, electron transporting compounds or hole transporting compounds used together with the polymeric fluorescent substance can be used. Examples of the hole transporting compound include a pyrazoline derivative, an arylamine derivative, a stilbene derivative, and a triphenyldiamine derivative. Examples of the electron transporting compound include an oxadiazole derivative, anthraquinodimethane or a derivative thereof, and benzoquinone or a derivative thereof. Derivatives,
Examples include naphthoquinone or a derivative thereof, anthraquinone or a derivative thereof, tetracyanoanthraquinodimethane or a derivative thereof, a fluorenone derivative, diphenyldicyanoethylene or a derivative thereof, a diphenoquinone derivative, or a metal complex of 8-hydroxyquinoline or a derivative thereof. More specifically,
JP-A-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-209988, JP-A-3-37992, and JP-A-3-152184. Are shown.

Of these, a triphenyldiamine derivative is preferable as the hole transporting compound used in the light emitting layer, and an oxadiazole derivative, benzoquinone or a derivative thereof, as the electron transporting compound used in the light emitting layer.
Metal complexes of anthraquinone or a derivative thereof, or 8-hydroxyquinoline or a derivative thereof, in particular, as a hole-transporting compound, 4,4′-bis (N (3-methylphenyl) -N-phenylamino) biphenyl, As the transportable compound, 2- (4-biphenylyl)-
5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, and tris (8-quinolinol) aluminum are preferred. Among them, one or both of the electron transporting compound and the hole transporting compound may be used simultaneously. These may be used alone or as a mixture of two or more.

[0075]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Here, regarding the number average molecular weight, the number average molecular weight in terms of polystyrene was determined by gel permeation chromatography (GPC) using chloroform as a solvent. <Preparation of Liquid Crystal Polyester Resin Composition Film> A method for producing a film made of the liquid crystal polyester resin composition for the protective layer used in the examples is as follows. p-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4, 4 '
Diacetoxydiphenyl (60/15/5 / 20.2
(Mol)) was charged into a polymerization apparatus having a stirring blade, and polymerized at 330 ° C. for 1 hour while stirring under a nitrogen gas atmosphere.
The mixture was further treated at 280 ° C. for 3 hours to obtain a liquid crystal polyester having a melting temperature of 324 ° C. Said liquid crystal polyester, methyl acrylate / ethylene / glycidyl methacrylate (59.0 / 48.7 / 2.3 (weight ratio)) and Mooney viscosity produced based on the description in Example 5 of JP-A-61-127709. (100 ° C.) = 15 was melt-kneaded with a twin-screw extruder at a set temperature of 340 ° C. to obtain a liquid crystal polyester resin composition. The liquid crystal polyester resin composition was melt-extruded at 350 ° C. using a 50 mm diameter single screw extruder equipped with a 50 mm diameter annular slit die with a 1 mm interval, stretched by an inflation method, and stretched.
A liquid crystal polyester resin composition film of 5 μm to 40 μm was obtained. The oxygen permeability of the film is 0.4 cc / m ²
・ 24hr ・ 1atm, water vapor permeability is 0.5g / m ²
・ 24 hr · 1 atm.

Example 1 <Synthesis of polymeric fluorescent substance 1> 2,5-dioctyloxy-
p-Xylylene dibromide was reacted with triphenylphosphine in N, N-dimethylformamide solvent to synthesize a phosphonium salt. 47. The obtained phosphonium salt
75 parts by weight and 6.7 parts by weight of terephthalaldehyde were dissolved in ethyl alcohol. An ethyl alcohol solution containing 5.8 parts by weight of lithium ethoxide was added dropwise to an ethyl alcohol solution of a phosphonium salt and dialdehyde, and polymerized at room temperature for 3 hours. After leaving overnight at room temperature,
The precipitate was separated by filtration, washed with ethyl alcohol, dissolved in chloroform, and ethanol was added thereto to reprecipitate. This was dried under reduced pressure to obtain 8.0 parts by weight of a polymer. This is called polymeric fluorescent substance 1. The repeating units of polymeric fluorescent substance 1 calculated from the charged ratio of the monomers and the molar ratios thereof are shown below.

Embedded image (The ratio of the two repeating units is 50:50,
The two repeating units are connected alternately. The polystyrene-equivalent number average molecular weight of the polymeric fluorescent substance 1 was 1.0 × 10 ⁴ . The structure of the polymeric fluorescent substance 1 was confirmed by an infrared absorption spectrum and NMR.

<Preparation and Evaluation of Element> A 50-nm-thick film was formed by dipping on a glass substrate on which a 40-nm-thick ITO film had been formed by sputtering, using a 1.0 wt% chloroform solution of polyvinyl carbazole. Furthermore, a 50 nm-thick film was formed by spin coating using a 1.0 wt% toluene solution of the polymeric fluorescent substance 1. Further, this was dried at 120 ° C. for 1 hour under reduced pressure, and then tris (8-quinolinol) aluminum (Alq ₃ ) was used as an electron transporting layer at 0.1 to 0.2 nm.
/ S was evaporated at a rate of 35 nm. A 40 nm thick lithium-aluminum alloy (lithium concentration: 1 wt%) was vapor-deposited thereon as a first metal layer of a cathode to produce an organic EL device. The degree of vacuum at the time of vapor deposition is 8 × 10 ^-6 T
orr or less. After the electrodes were formed, 5 μm was placed around an organic EL element formed on a transparent glass substrate in a nitrogen atmosphere.
A liquid crystal polyester resin composition film is placed on the photocurable resin (trade name: Technodyne, manufactured by Kyoritsu Chemical Co., Ltd.) mixed with the above silica gap material, and the substrate and the liquid crystal polyester resin composition film are bonded to each other. Thus, an organic EL element protective layer was produced. A voltage of 12.
When 5 V was applied, the current density was 32.1 mA / cm ²
Of yellow-green EL with a luminance of 1892 cd / m ²
Luminescence was observed. The luminous efficiency at this time is 5.9 cd /
A. The brightness was almost proportional to the current density. In addition, the EL peak wavelength was 540 nm, which almost coincided with the fluorescence peak wavelength of the thin film of the polymeric fluorescent substance 1, and EL emission from the polymeric fluorescent substance 1 was confirmed. This element was heated at 40 ° C.
After storage at 90 RH% for 5 days, the device was driven at a low voltage of 10 V. As a result, the growth of dark spots was small, and the area of the non-light emitting portion was 10% or less.

Example 2 <Preparation and evaluation of device> A polyether sulfone film substrate with an ITO film having a thickness of 100 μm and a surface resistivity of 100Ω (transparent conductive film: trade name: FST-5337, manufactured by Sumitomo Bakelite Co., Ltd.) was prepared. Using a bar coater, a 1.0 wt% methylene chloride solution of polyvinyl carbazole was first applied and dried, and then 1.0 wt% of polymeric fluorescent substance 1 was dried.
% Toluene solution was applied. As a result, an organic layer having a two-layer structure in which polyvinyl carbazole is laminated with a thickness of 50 nm and the polymeric fluorescent substance 1 is laminated with a thickness of 50 nm is formed on the polyethersulfone film film substrate with the ITO film. Was done. Further, after drying the coated film at 80 ° C. for 1 hour under reduced pressure, 35 nm of tris (8-quinolinol) aluminum (Alq ₃ ) was vapor-deposited at a rate of 0.1 to 0.2 nm / s as an electron transport layer. . A 40 nm thick lithium-aluminum alloy was deposited thereon to produce an organic EL device. The degree of vacuum at the time of vapor deposition was 8 × 10 ⁻⁶ Torr or less. After the electrode was made, a photo-curable resin (manufactured by Kyoritsu Chemical Co., Ltd., trade name: Technodyne) in which a 5 μm silica gap material was mixed around the organic EL element formed on the transparent glass substrate in a nitrogen atmosphere. A liquid crystal polyester resin composition film was placed thereon, and the substrate and the liquid crystal polyester resin composition film were bonded to each other to prepare an organic EL element protective layer. When a voltage of 12.5 V was applied to this element, a current density of 32.1 V
A current of mA / cm ² flowed, and yellow-green EL emission with a luminance of 1892 cd / m ² was observed. The luminous efficiency at this time is
It was 5.9 cd / A, and even when the substrate was wound around a rod having a diameter of 2 cm, there was almost no occurrence of a non-light-emitting portion (dark spot) and a decrease in efficiency. The brightness was almost proportional to the current density. In addition, the EL peak wavelength was 540 nm, which substantially coincided with the fluorescence peak wavelength of the thin film of the polymer fluorescent substance 1, and EL emission from the polymer fluorescent substance 1 was confirmed. This element is 4
After storage at 0 ° C. and 90 RH% for 5 days, the device was driven at a low voltage of 10 V. As a result, the growth of dark spots was small, and the area of the non-light emitting portion was 10% or less.

Comparative Example 1 The same as Example 1 except that the protective layer of the organic EL device was not used.
The device was prepared by the same method. Apply a voltage of 12.5V to this element
When applied, the current density was 32.1 mA / cm ^TwoCurrent
Flows and the brightness is 1892 cd / m^TwoYellow-green EL emission
Was observed. The luminous efficiency at this time is 5.9 cd / A.
Was. The brightness was almost proportional to the current density. Also, EL
The peak wavelength is 540 nm.
It almost coincides with the light peak wavelength,
EL emission was confirmed. This device was used at 40 ° C. and 90 RH%.
After driving for 5 days at low voltage at 10V,
Many spots were generated, and no light was emitted.

As described above, the organic EL devices of Examples 1 and 2 protected by the liquid crystal polyester resin composition film were different from the organic EL devices of Comparative Example 1 not protected by the liquid crystal polyester resin composition film. In this case, the dark spot growth was small, and excellent storage characteristics with excellent luminous display quality were exhibited.

[0081]

The organic EL device of the present invention is very stable because it uses a polymer material having a relatively high melting point and decomposition temperature, and can easily form a light emitting layer by a coating method. An organic EL device having high luminance and high luminous efficiency can be easily manufactured. In particular, since most of the dark spots do not grow even during long-term storage, they can be preferably used as devices such as a planar light source as a backlight and a flat panel display, and have great industrial value. The organic EL devices of Examples 1 and 2 in which the polymer fluorescent material and the cathode are separated from each other by a film made of a liquid crystal polyester resin composition so as not to come into contact with the outside air, are easy to manufacture and have excellent light emitting display quality. Shows the storage characteristics of
In Comparative Example 1 having no film, dark spots were frequently generated.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one example of an organic electroluminescence device of the present invention.

FIG. 2 is a schematic cross-sectional view of an example of the organic electroluminescence device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Thermosetting resin or photocurable resin 3 ... Inert gas layer 4 ... Film made of liquid crystal polyester resin composition 5 ... Metal foil for taking out electrode 6. ..Cathode 7 ... Organic layer 8 ... Anode

Claims (17)

[Claims] An organic electroluminescent device having at least a light emitting layer between a pair of anodes and cathodes, at least one of which is transparent or translucent, wherein the light emitting layer has fluorescence in a solid state, and has the following general formula: (1)
Is 50 mol% of all repeating units.
And the number average molecular weight in terms of polystyrene is 10 ³
It includes a polymeric fluorescent substance is 10 ^7, and at least a portion of the surface of the organic electroluminescent device is an epoxy liquid crystal polyester from 65.0 to 99.9% by weight and of component (A) (B) Group-containing copolymer
An organic electroluminescence device, which is covered with a film made of a liquid crystal polyester resin composition containing 5.0 to 0.1% by weight. Embedded image -Ar-CR = CR′- (1) [where Ar has 4 carbon atoms participating in a conjugate bond.
Represents an arylene group or a heterocyclic compound group consisting of at least 20 and at most 20, and R and R ′ each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms,
It represents a group selected from the group consisting of a heterocyclic compound having 4 to 20 carbon atoms and a cyano group. ] 2. The method according to claim 1, wherein the anode or the cathode is a transparent electrode made of a metal oxide formed on the polymer film, and the transparent electrode is disposed on the light emitting layer side with respect to the polymer film. The surface on the side opposite to the light emitting layer side of the polymer film or the surface between the light emitting layer side of the polymer film and the transparent electrode is covered with a gas barrier inorganic material and / or a hard coat material. The organic electroluminescence device according to claim 1, wherein 3. The organic electroluminescent device according to claim 1, further comprising a layer containing an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer. 4. The organic electroluminescence device according to claim 1, further comprising a layer containing a hole transporting compound adjacent to the light emitting layer between the anode and the light emitting layer. 5. A layer containing an electron transporting compound between the cathode and the light emitting layer, adjacent to the light emitting layer, and a hole transporting layer between the anode and the light emitting layer, adjacent to the light emitting layer. The organic electroluminescence device according to claim 1, further comprising a layer containing a reactive compound. 6. The organic electroluminescence according to claim 1, wherein a film made of the liquid crystal polyester resin composition is thermocompression bonded to at least a part of the surface of the organic electroluminescence element. element. 7. A film made of a liquid crystal polyester resin composition is adhered to at least a part of the surface of an organic electroluminescence element with a photocurable resin or a thermosetting resin. The organic electroluminescent device according to any one of the above. 8. The copolymer having an epoxy group as the component (B), comprising an unsaturated carboxylic acid glycidyl ester unit and / or
The organic electroluminescent device according to any one of claims 1 to 7, further comprising 0.1 to 30% by weight of an unsaturated glycidyl ether unit. 9. The copolymer having an epoxy group of component (B) comprises: (a) 50 to 99.9% by weight of ethylene units;
(B) When the content of unsaturated glycidyl carboxylate ester units and / or unsaturated glycidyl ether units is 0.
The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is an ethylene copolymer having 1 to 50% by weight and having an epoxy group. 10. The copolymer having an epoxy group of component (B) comprises: (a) 50 to 99.89% by weight of ethylene units;
(B) When the content of unsaturated glycidyl carboxylate ester units and / or unsaturated glycidyl ether units is 0.
8. An epoxy group-containing ethylene copolymer comprising 1 to 49.99% by weight and (c) 0.01 to 49.9% by weight of an ethylenically unsaturated ester compound unit. The organic electroluminescent device according to any one of the above. 11. The copolymer having an epoxy group of component (B) contains (meth) acrylate-ethylene- (unsaturated glycidyl carboxylate and / or unsaturated glycidyl ether) copolymer rubber. The organic electroluminescent device according to claim 1, wherein: 12. The copolymer having an epoxy group of the component (B) having a (meth) acrylate unit of 40 to 96.
A copolymer rubber comprising 9% by weight, 3 to 50% by weight of ethylene units, and 0.1 to 10% by weight of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units. Item 8. The organic electroluminescent device according to any one of Items 1 to 7. 13. The copolymer rubber according to claim 11 or 12, wherein the Mooney viscosity of the copolymer rubber (the Mooney viscosity referred to herein is a value measured according to JIS K6300) is in the range of 3 to 30. The organic electroluminescent device according to the above. 14. The organic electroluminescent device according to claim 1, wherein the liquid crystal polyester as the component (A) contains at least 30 mol% of the following repeating structural units. Embedded image 15. The liquid crystal polyester as the component (A), which is obtained by reacting an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic or aliphatic diol. 8. The organic electroluminescent device according to any one of 7. 16. The organic electroluminescent device according to claim 1, wherein the liquid crystal polyester as the component (A) is obtained by reacting a combination of different aromatic hydroxycarboxylic acids. Luminescent element. 17. The liquid crystal polyester as the component (A), which is obtained by reacting an aromatic dicarboxylic acid with an aromatic or aliphatic diol.
8. The organic electroluminescence device according to any one of items 1 to 7,