JP7360131B2 - Encapsulant for organic electroluminescent display elements - Google Patents

Description

The present invention relates to a sealant for organic electroluminescent display elements.

Organic electroluminescent (EL) devices (also referred to as OLED devices) are attracting attention as device bodies that can emit light with high brightness. However, OLED elements have a problem in that they are degraded by oxygen and moisture, resulting in a decrease in light-emitting characteristics.

In order to solve such problems, techniques for sealing organic EL elements and preventing deterioration due to moisture are being considered. For example, there is a method of sealing with a sealing material made of frit glass (see Patent Document 1).

An organic electroluminescent display element characterized in that the sealing layer is a laminate in which at least a barrier layer, a resin layer, and a barrier layer are sequentially formed (see Patent Document 2); an inorganic film and an organic film for sealing an organic EL element. and a sealing glass substrate disposed in close contact with the uppermost organic film of the sealing layer so as to cover the entire upper surface of the uppermost organic film. An organic EL device (see Patent Document 3) has been proposed.

As a resin composition for sealing an organic EL element, a sealing agent for an organic electroluminescent display element containing a cyclic ether compound, a cationic polymerization initiator, and a polyfunctional vinyl ether compound (see Patent Document 4), a cationically polymerizable resin composition A cationically polymerizable resin composition containing a compound and a photocationic polymerization initiator or a thermal cationic polymerization initiator has been proposed (see Patent Document 5). (Meth)acrylic resin compositions have been proposed as resin compositions for sealing organic EL elements (Patent Documents 6 to 14).

Japanese Patent Application Publication No. 10-74583 Japanese Patent Application Publication No. 2001-307873 JP2009-37812A Japanese Patent Application Publication No. 2014-225380 Japanese Patent Application Publication No. 2012-190612 JP2014-229496A Japanese Patent Application Publication No. 2014-196387 Japanese Patent Application Publication No. 2014-193970 Japanese Patent Application Publication No. 2014-193971 WO2014/157642 publication US2017/0062762 publication Special table 2017-536429 publication Special table 2018-504735 publication WO2016/068415 publication

However, the conventional technology described in the above-mentioned document had room for improvement in the following points.

In Patent Document 1, when mass-producing the organic EL element, a method is adopted in which the organic EL element is sandwiched between base materials with low moisture permeability, such as glass, and the outer periphery is sealed. In this case, since this structure is a hollow sealing structure, it is not possible to prevent moisture from entering the hollow sealing structure, which causes a problem that leads to deterioration of the organic EL element.

In Patent Documents 2 and 3, since the organic film is formed by vapor deposition, there is a problem that the thickness of the organic film is 3 μm or less. If the thickness of the organic film is 3 μm or less, not only will particles generated during device formation not be completely covered, but it will also be difficult to coat the inorganic film while maintaining flatness.

Patent Document 4 proposes a sealant using an epoxy material, but such materials require heating to cure, which can damage organic EL elements and pose problems in terms of yield. Ta. Patent Document 5 proposes a photocurable encapsulant using an epoxy material, but since such materials are cured by UV light, UV light can damage organic EL elements and reduce yield. There were issues in this regard.

Patent Documents 6 to 10 and 12 to 14 describe reducing water vapor permeability as a necessary property of such sealing materials, but they do not allow the sealing material itself to penetrate through pinholes in the passivation film. , there is no description of the problems that reduce the reliability of organic EL elements and their countermeasures.

Although Patent Document 11 describes the use of cyclic monofunctional (meth)acrylate, it does not solve the problem that unreacted substances thereof become outgas, leading to poor light emission of organic EL devices.

As described above, the above-mentioned conventional technology has long had a problem in that it is not compatible with the ejection performance when using an inkjet and the reliability of the organic EL element.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composition that has excellent coating properties and low moisture permeability when used, for example, for sealing an organic EL element.

That is, the embodiment of the present invention can provide the following.

[1]
Contains (A) an alkanediol di(meth)acrylate having 4 to 20 carbon atoms and (B) a photopolymerization initiator, and the amount of hydrophilic functional groups per (meth)acrylate is 4.80 to 7.60 mmol/ A sealing agent for organic electroluminescent display elements in the range of g.

[2]
(C) further contains a (meth)acrylate other than the component (A), with the component (A) being 30 parts by mass or more and less than 100 parts by mass, based on a total of 100 parts by mass of the components (A) and (C); The encapsulant for organic electroluminescent display elements according to [1], containing 0.05 to 6 parts by mass of component (B) and more than 0 parts by mass and 70 parts by mass or less of component (C).

[3]
The encapsulant for organic electroluminescent display elements according to [2], wherein the amount of hydrophilic functional groups per (meth)acrylate in component (C) is 3.00 to 15.00 mmol/g.

[4]
The sealant for organic electroluminescent display elements according to any one of [1] to [3], which has a viscosity of 2 mPa·s or more and 50 mPa·s or less as measured by an E-type viscometer at 25°C.

[5]
The sealant for organic electroluminescent display elements according to any one of [1] to [4], which has a water content of 90 ppm or less.

[6]
The sealant for an organic electroluminescent display element according to any one of [1] to [5], wherein the amount of dissolved oxygen is 1 ppm or more and 20 ppm or less.

[7]
The encapsulant for organic electroluminescent display elements according to any one of [1] to [6], which does not contain a bifunctional (meth)acrylate oligomer/polymer and a polyfunctional (meth)acrylate oligomer/polymer.

[8]
The encapsulant for an organic electroluminescent display element according to any one of [1] to [7], wherein the component (A) is an alkanediol di(meth)acrylate having 12 to 16 carbon atoms.

[9]
The encapsulant for an organic electroluminescent display element according to any one of [1] to [8], wherein the component (A) is 1,12-dodecanediol di(meth)acrylate.

[10]
Component (C) is one or more of the group consisting of alkyl (meth)acrylates having 8 or more carbon atoms, (meth)acrylates having an alicyclic hydrocarbon group, and (meth)acrylates having an aromatic hydrocarbon group. The sealant for an organic electroluminescent display element according to any one of [2] to [9].

[11]
The encapsulant for an organic electroluminescent display element according to any one of [2] to [10], wherein the component (C) contains lauryl (meth)acrylate.

[12]
Component (C) is dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyloxy The encapsulant for organic electroluminescent display elements according to any one of [2] to [11], which contains one or more members of the group consisting of ethyl (meth)acrylate.

[13]
The encapsulant for an organic electroluminescent display element according to any one of [2] to [12], wherein the component (C) contains ethoxylated-o-phenylphenol (meth)acrylate.

[14]
The encapsulant for an organic electroluminescent display element according to any one of [1] to [13], wherein the component (B) is an acylphosphine oxide derivative.

[15]
A cured product obtained by curing the sealant for organic electroluminescent display elements according to any one of [1] to [14].

[16]
A bonded body bonded with the sealant for organic electroluminescent display elements according to any one of [1] to [14].

[17]
The method for curing a sealant for an organic electroluminescent display element according to any one of [1] to [14], characterized in that curing is performed using a wavelength of 380 nm or more and 500 nm or less.

[18]
The method for curing a sealant for an organic electroluminescent display element according to any one of [1] to [14], characterized in that curing is performed using an LED lamp with an emission wavelength of 395 nm.

[19]
The method for applying a sealant for an organic electroluminescent display element according to any one of [1] to [14], which is applied using an inkjet method.

[20]
An organic EL device comprising the sealant for organic electroluminescent display elements according to any one of [1] to [14].

[21]
A display comprising the sealant for organic electroluminescent display elements according to any one of [1] to [14].

The encapsulant according to the present invention has excellent ejection properties when using an inkjet method, and has the effect that the resulting organic EL device has excellent reliability, coating properties, and low moisture permeability.

This embodiment will be described below.
This embodiment relates to a sealant for organic electroluminescent display elements. This embodiment relates to a (meth)acrylic resin composition that can be used, for example, as a sealant for organic electroluminescence (EL) display elements.

The numerical ranges described herein include upper and lower limits, unless otherwise specified. In this specification, unless otherwise specified, the following definitions are used. (Meth)acrylate represents acrylate or methacrylate, and expressions such as "(meth)acryloyloxy" and "(meth)acrylamide" have the same meaning. "Monofunctional (meth)acrylate" refers to (meth)acrylate having one (meth)acrylic group, and "bifunctional (meth)acrylate" refers to (meth)acrylate having two (meth)acrylic groups. Point. "Polyfunctional (meth)acrylate" refers to (meth)acrylate having three or more (meth)acrylic groups, and does not include bifunctional (meth)acrylate.

Hereinafter, a top emission type organic EL device in which light is emitted from the side opposite to the substrate of an organic EL element formed on a substrate will be described as an example. A top emission type organic EL device includes an organic EL element in which an anode, an organic EL layer including a light-emitting layer, and a cathode are laminated in this order on a substrate, and an inorganic film and an organic film are laminated to cover the entire organic EL element. It has a structure in which a sealing layer made of a film and a sealing substrate provided on the sealing layer are formed in this order.

Various substrates can be used as the substrate, such as a glass substrate, a silicon substrate, and a plastic substrate. Among these, one or more of the group consisting of glass substrates and plastic substrates are preferred, and glass substrates are more preferred.

Plastics used for plastic substrates include polyimide, polyetherimide, polyethylene terephthalate, polyethylene naphthalate, polyoxadiazole, aromatic polyamide, polybenzimidazole, polybenzobisthiazole, polybenzoxazole, polythiazole, and polyparaphenylene. Examples include vinylene, polymethyl methacrylate, polystyrene, polycarbonate, polycycloolefin, polyacrylic, and the like. Among these, polyimide, polyetherimide, polyethylene terephthalate, polyethylene naphthalate, polyoxadiazole, aromatic polyamide, polybenzimidazole, polybenzo One or more selected from the group consisting of bisthiazole, polybenzoxazole, polythiazole, and polyparaphenylene vinylene are preferred, and polyimide, polyetherimide, and polyethylene terephthalate are preferable because they have high transparency to energy rays such as ultraviolet rays or visible rays. , polyethylene naphthalate is more preferred.

As the anode, a conductive metal oxide film, a translucent metal thin film, or the like having a relatively large work function (preferably one having a work function larger than 4.0 eV) is used. Examples of materials for the anode include indium tin oxide (hereinafter referred to as ITO), metal oxides such as tin oxide, gold (Au), platinum (Pt), silver (Ag), copper (Cu), etc. or an alloy containing at least one of these metals, organic transparent conductive films such as polyaniline or its derivatives, polythiophene or its derivatives, and the like. The anode can be formed with a layer structure of two or more layers, if necessary. The film thickness of the anode can be selected as appropriate, taking into consideration electrical conductivity (and light transmittance in the case of a bottom emission type). The thickness of the anode is preferably 10 nm to 10 μm, more preferably 20 nm to 1 μm, and most preferably 50 nm to 500 nm. Examples of methods for producing the anode include vacuum evaporation, sputtering, ion plating, and plating. In the case of a top emission type, a reflective film may be provided under the anode to reflect light emitted to the substrate side.

The organic EL layer includes at least a light emitting layer made of an organic substance. This luminescent layer contains a luminescent material. Examples of the luminescent material include organic substances (low-molecular compounds or high-molecular compounds) that emit fluorescence or phosphorescence. The light emitting layer may further contain a dopant material. Examples of the organic substance include dye-based materials, metal complex-based materials, polymeric materials, and the like. A dopant material is doped into an organic substance for the purpose of improving the luminous efficiency of the organic substance, changing the emission wavelength, or the like. The thickness of the light-emitting layer made of these organic substances and a dopant doped as necessary is usually 2 to 200 nm.

(dye material)
Examples of dye materials include cyclopendamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophene ring compounds, and pyridine. Examples include ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifmanylamine derivatives, oxadiazole dimers, and pyrazoline dimers.

(Metal complex material)
Metal complex materials include metal complexes that emit light from the triplet excited state such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzothiazole zinc complexes, and azomethyl zinc complexes. , a porphyrin zinc complex, a europium complex, and the like. The metal complex has a central metal such as a rare earth metal such as terbium (Tb), europium (Eu), or dysprosium (Dy), aluminum (Al), zinc (Zn), or beryllium (Be), and has a ligand. Examples include metal complexes having oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, and quinoline structures. Among these, metal complexes having aluminum (Al) as a central metal and having a quinoline structure or the like as a ligand are preferred. Among metal complexes having aluminum (Al) as a central metal and a quinoline structure as a ligand, tris(8-hydroxyquinolinato)aluminum is preferred.

(polymer material)
Examples of polymeric materials include polyparaphenylenevinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and substances obtained by polymerizing the above-mentioned color bodies and metal complex luminescent materials. can be mentioned.

Among the above luminescent materials, examples of materials that emit blue light include distyrylarylene derivatives, oxadiazole derivatives, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among the polymeric materials, one or more selected from the group consisting of polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

Examples of materials that emit green light include quinacridone derivatives, coumarin derivatives, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among the polymer materials, one or more selected from the group consisting of polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.

Examples of materials that emit red light include coumarin derivatives, thiophene ring compounds, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyfluorene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among the polymer materials, one or more selected from the group consisting of polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferred.

(Dopant material)
Examples of the dopant material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, and phenoxazone.

In addition to the light-emitting layer, the organic EL layer can appropriately include a layer provided between the light-emitting layer and the anode, and a layer provided between the light-emitting layer and the cathode. First, the layer provided between the light emitting layer and the anode includes a hole injection layer that improves hole injection efficiency from the anode, and a hole injection layer that transports holes injected from the anode or hole injection layer to the light emitting layer. Examples include a hole transport layer. Examples of the layer provided between the light emitting layer and the cathode include an electron injection layer that improves the efficiency of electron injection from the cathode, and an electron transport layer that transports electrons injected from the cathode or the electron injection layer to the light emitting layer. It will be done.

(hole injection layer)
Examples of materials for forming the hole injection layer include phenylamine-based materials such as 4,4',4"-tris{2-naphthyl(phenyl)amino}triphenylamine, starburst amine-based materials, phthalocyanine-based materials, vanadium oxide, Examples include oxides such as molybdenum oxide, ruthenium oxide, and aluminum oxide, amorphous carbon, polyaniline, and polythiophene derivatives.

(hole transport layer)
Materials constituting the hole transport layer include polyvinylcarbazole or its derivatives, polysilane or its derivatives, polysiloxane derivatives having an aromatic amine in the side chain or main chain, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine. derivatives, benzidine derivatives, polyaniline or its derivatives, polythiophene or its derivatives, polyarylamines or its derivatives, polypyrrole or its derivatives, poly(p-phenylene vinylene) or its derivatives, poly(2,5-thienylene vinylene) or its derivatives Examples include derivatives. Examples of benzidine derivatives include N,N'-diphenyl-N,N'-dinaphthylbenzidine.

When these hole injection layers or hole transport layers have a function of blocking electron transport, these hole transport layers or hole injection layers are sometimes referred to as electron blocking layers.

(electron transport layer)
Materials constituting the electron transport layer include oxadiazole derivatives, anthraquinodimethane or its derivatives, benzoquinone or its derivatives, naphthoquinone or its derivatives, anthraquinone or its derivatives, tetracyanoanthraquinodimethane or its derivatives, and fluorenone derivatives. , diphenyldicyanoethylene or its derivatives, diphenoquinone derivatives, 8-hydroxyquinoline or its derivatives, polyquinoline or its derivatives, polyquinoxaline or its derivatives, polyfluorene or its derivatives, and the like. Examples of derivatives include metal complexes. Among these, 8-hydroxyquinoline or its derivatives are preferred. Among 8-hydroxyquinoline and its derivatives, tris(8-hydroxyquinolinato)aluminum is preferred since it can also be used as an organic substance that emits fluorescence or phosphorescence and is contained in a light-emitting layer.

(electron injection layer)
Depending on the type of emissive layer, the electron injection layer may be an electron injection layer consisting of a single layer structure of a calcium (Ca) layer, or an electron injection layer made of a metal from Group IA or Group IIA of the periodic table and having a work function of 1. Examples include an electron injection layer having a laminated structure of a Ca layer and a layer formed of one or more of the group consisting of a metal with a voltage of .5 to 3.0 eV and its oxide, halide, and carbonate. . Examples of metals of Group IA of the periodic table or their oxides, halides, and carbonates having a work function of 1.5 to 3.0 eV include lithium (Li), lithium fluoride, sodium oxide, lithium oxide, lithium carbonate, etc. can be mentioned. Examples of metals of Group IIA of the periodic table or their oxides, halides, and carbonates having a work function of 1.5 to 3.0 eV include strontium (Sr), magnesium oxide, magnesium fluoride, strontium fluoride, and fluoride. Examples include barium, strontium oxide, magnesium carbonate, and the like.

When these electron transport layers or electron injection layers have a function of blocking hole transport, these electron transport layers or electron injection layers are sometimes referred to as hole blocking layers.

The cathode is preferably a transparent or translucent material that has a relatively small work function (preferably one with a work function smaller than 4.0 eV) and can easily inject electrons into the light emitting layer. The materials for the cathode include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), beryllium (Be), magnesium (Mg), calcium (Ca), and strontium (Sr). , barium (Ba), aluminum (Al), scandium (Sc), vanadium (V), zinc (Zn), yttrium (Y), indium (In), cerium (Ce), samarium (Sm), europium (Eu) , terbium (Tb), ytterbium (Yb), or an alloy consisting of two or more of the above metals, or one or more of them, and gold (Au), silver (Ag), platinum (Pt), An alloy consisting of one or more of copper (Cu), chromium (Cr), manganese (Mn), titanium (Ti), cobalt (Co), nickel (Ni), tungsten (W), and tin (Sn), or , graphite or graphite intercalation compounds, or metal oxides such as ITO and tin oxide.

The cathode may have a laminated structure of two or more layers. Examples of the laminated structure of two or more layers include a laminated structure of the above-mentioned metals, metal oxides, fluorides, and alloys thereof and metals such as Al, Ag, and Cr. The film thickness of the cathode can be appropriately selected in consideration of electrical conductivity and durability. The thickness of the cathode is preferably 10 nm to 10 μm, more preferably 15 nm to 1 μm, and most preferably 20 nm to 500 nm. Examples of methods for producing the cathode include a vacuum evaporation method, a sputtering method, and a lamination method in which a metal thin film is bonded by thermocompression.

The layers provided between the light emitting layer and the anode and between the light emitting layer and the cathode can be appropriately selected depending on the performance required of the organic EL device to be manufactured. For example, the structure of the organic EL element used in this embodiment can have any of the following layer configurations (i) to (xv).
(i) Anode/hole transport layer/emissive layer/cathode (ii) anode/emissive layer/electron transport layer/cathode (iii) anode/hole transport layer/emissive layer/electron transport layer/cathode (iv) anode/ Hole injection layer / Emissive layer / Cathode (v) Anode / Emissive layer / Electron injection layer / Cathode (vi) Anode / Hole injection layer / Emissive layer / Electron injection layer / Cathode (vii) Anode / Hole injection layer / Hole transport layer / Emissive layer / Cathode (viii) Anode / Hole transport layer / Emissive layer / Electron injection layer / Cathode (ix) Anode / Hole injection layer / Hole transport layer / Emissive layer / Electron injection layer / Cathode (x) Anode/hole injection layer/emissive layer/electron transport layer/cathode (xi) anode/emissive layer/electron transport layer/electron injection layer/cathode (xii) anode/hole injection layer/emissive layer/electron transport Layer/electron injection layer/cathode (xiii) anode/hole injection layer/hole transport layer/emissive layer/electron transport layer/cathode (xiv) anode/hole transport layer/emissive layer/electron transport layer/electron injection layer /Cathode (xv) Anode/Hole injection layer/Hole transport layer/Light emitting layer/Electron transport layer/Electron injection layer/Cathode (here, "/" indicates that each layer is stacked adjacent to each other. same as below.)

The sealing layer is provided to prevent gases such as water vapor and oxygen from coming into contact with the organic EL element, and to seal the organic EL element with a layer having high barrier properties against the gases. In this sealing layer, an inorganic film and an organic film are alternately formed from below. The inorganic/organic laminate may be formed two or more times.

The inorganic film of the inorganic/organic laminate is a film provided to prevent the organic EL element from being exposed to gases such as water vapor and oxygen present in the environment in which the organic EL device is placed. The inorganic film of the inorganic/organic laminate is preferably a continuous, dense film with few defects such as pinholes. Examples of the inorganic film include single films such as SiN film, SiO film, SiON film, Al ₂ O ₃ film, and AlN film, and laminated films of these films.

The organic film of the inorganic/organic laminate is provided to cover defects such as pinholes formed on the inorganic film and to impart flatness to the surface. The organic film is formed in an area narrower than the area where the inorganic film is formed. This is because if the organic film is formed to be as wide as or wider than the region where the inorganic film is formed, the organic film will deteriorate in the exposed region. However, the uppermost organic film formed on the top layer of the entire sealing layer is formed in almost the same area as the inorganic film. Then, the sealing layer is formed so that the upper surface thereof is flattened. As the organic film, a composition having good adhesion to the above-mentioned inorganic film is used.

This embodiment is suitable, for example, for inkjet coating, which allows coating with excellent flatness to a film thickness of 3 μm or more in a short time, has excellent inkjet ejection properties and flatness after inkjet coating, and has excellent barrier properties against water vapor, etc. An organic electroluminescent display element that forms the above-mentioned organic film, which not only has low moisture permeability (hereinafter also referred to as low moisture permeability), but also allows the sealant itself to penetrate through pinholes on the inorganic film, so that the reliability of the organic EL element does not deteriorate. The purpose is to provide a sealant for If an inkjet coating method is used, an organic film can be formed uniformly at high speed.

The viscosity of the composition of the present embodiment is preferably 2 mPa·s or more and 50 mPa·s or less when measured using an E-type viscometer at 25° C. and 100 rpm. If it is difficult to eject by inkjet, warm the inkjet head as appropriate. If the viscosity is 2 mPa・s or more, the applied sealant for organic EL display elements will not flow out from the organic EL display element before curing and will not flow into the pinholes on the inorganic film, reducing the reliability of the OLED element. will improve. When the viscosity is 50 mPa·s or less, it becomes easy to apply by inkjet. The viscosity of the composition is more preferably 5 mPa·s to 30 mPa·s.

The composition of the present embodiment is a (meth)acrylic resin composition containing (A) an alkanediol di(meth)acrylate having 4 to 20 carbon atoms and (B) a photopolymerization initiator. In this specification, when the number of carbon atoms is expressed for the main chain (alkanediol, etc.), the number of carbon atoms in the (meth)acrylate moiety is not included.

(A) Alkanes in the alkanediol di(meth)acrylate having 4 to 20 carbon atoms include chain compounds and cyclic compounds. As the alkane, chain compounds are preferred. The chain compound may be a straight chain compound or a branched chain compound. As the alkane, saturated hydrocarbons are preferred.

(A) Alkanediol di(meth)acrylates having 4 to 20 carbon atoms (alkane is a chain compound and saturated hydrocarbon) include 1,2-butanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, and 1,3-butanediol di(meth)acrylate. (meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate ) acrylate, 1,7-octanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate , 1,11-undecanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,13-tridecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,15-pentadecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,17-heptadecanediol di(meth)acrylate, 1,18-octadecanediol di(meth)acrylate, 1 , 19-nonadecanediol di(meth)acrylate, 1,20-icosanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2,4-diethyl-1,5 - Pentanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, etc. (A) Alkanediol di(meth)acrylates having 4 to 20 carbon atoms (alkane is a cyclic compound) include 1,2-cyclohexanediol di(meth)acrylate, 1,3-cyclohexanediol di(meth)acrylate , 1,4-cyclohexanediol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, hydrogenated bisphenol A di(meth)acrylate, and the like. Among alkanediol di(meth)acrylates having 4 or more carbon atoms and 20 or less carbon atoms, it is better to have a large number of carbon atoms in the main chain from the viewpoint of reliability for OLED devices, but the composition may crystallize during storage. Storage stability issues arise, such as the formation of crystallized products. From the viewpoint of reliability, moisture permeability, and storage stability of the OLED element, the number of carbon atoms is preferably 6 or more and 18 or less, more preferably 9 or more and 16 or less, even more preferably 12 or more and 16 or less, and most preferably 12. Among component (A), 1,12-dodecanediol di(meth)acrylate is preferred. Examples of component (A) include "1.9ND-A" (trade name) manufactured by Kyoeisha Kagaku Co., Ltd. and "SR262" (trade name) manufactured by Sartomer Corporation.

(B) The photopolymerization initiator is used to promote photocuring of the resin composition by sensitizing it with active light such as visible light or ultraviolet light. As the photopolymerization initiator, a radical photopolymerization initiator is preferable. Examples of the photoradical polymerization initiator include benzophenone and its derivatives, benzyl and its derivatives, entraquinone and its derivatives, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, benzoin derivatives such as benzyl dimethyl ketal, Acetophenone derivatives such as diethoxyacetophenone and 4-tert-butyltrichloroacetophenone, 2-dimethylaminoethylbenzoate, p-dimethylaminoethylbenzoate, diphenyl disulfide, thioxanthone and its derivatives, camphorquinone, 7,7-dimethyl-2,3 -dioxobicyclo[2.2.1]heptane-1-carboxylic acid, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-bromoethyl ester, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-methyl ester, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1 ] Camphorquinone derivatives such as heptane-1-carboxylic acid chloride, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- α-Aminoalkylphenone derivatives such as (4-morpholinophenyl)-butanone-1, benzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, benzoyldiethoxyphosphine oxide, 2,4,6 - Acylphosphine oxide derivatives such as trimethylbenzoyldimethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, phenyl-glyoxylic acid -Methyl ester, oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, etc. can be mentioned. One or more types of photopolymerization initiators can be used in combination. Among these, acylphosphine oxide derivatives are preferred because they can be cured using only visible light of 390 nm or more and can be cured without damaging the organic electroluminescent display element. Among acylphosphine oxide derivatives, 2,4,6-trimethylbenzoyl-diphenyl - Phosphine oxide is most preferred. Examples of the 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide include "Irgacure TPO" manufactured by BASF Japan.

(B) The content of the photopolymerization initiator is preferably 0.05 to 6 parts by mass, and 0.5 to 6 parts by mass, based on the total of 100 parts by mass of component (A) and optionally used component (C). More preferably 4 parts by weight, most preferably 2 to 3.9 parts by weight, even more preferably 2.2 to 3.5 parts by weight. If the content of component (C) is 0.05 parts by mass or more, the effect of accelerating curing can be reliably obtained, and if it is 6 parts by mass or less, the transmittance of visible light will decrease when used in a display. There's nothing to do.

（前記式において、材料とは各（メタ）アクリレート成分のことをいう）

（前記式において、材料とは各（メタ）アクリレート成分のことをいう）

上記親水性官能基量が４．８０ｍｍｏｌ／ｇ以上だと、反応性基である（メタ）アクリロイル基が多いため、反応性が高くなり、有機ＥＬ素子の封止性能を満足に発現し、低透湿性になるため有機ＥＬ素子の信頼性が向上し、平坦性が良くなる。７．６０ｍｍｏｌ／ｇ以下だと、信頼性試験中に有機エレクトロルミネッセンス表示素子用封止剤内部から水分が放出されにくく、有機発光材料層に水分が到達せず、ダークスポットが発生しにくい。反応性と信頼性の観点から、４．８０～７．６０ｍｍｏｌ／ｇが好ましく、５．００～７．１０ｍｍｏｌ／ｇがより好ましい。In the (meth)acrylic resin composition of the present embodiment, it is essential that the amount of hydrophilic functional groups per (meth)acrylate contained is 4.80 to 7.60 mmol/g. The amount of hydrophilic functional groups in the (meth)acrylic resin composition is determined by calculating the amount of hydrophilic functional groups per each (meth)acrylate of component (A) and, if present, component (C) using the following formula. Calculate the product by multiplying the amount of hydrophilic functional groups of each material by the mass fraction of each material blended in the (meth)acrylic resin composition as shown in the formula below, and calculate the sum of the (meth)acrylic This is the amount of hydrophilic functional groups in the resin composition. In calculating the mass fraction in the material, the total amount of (meth)acrylate was set to 100 parts by mass.

(In the above formula, material refers to each (meth)acrylate component)

(In the above formula, material refers to each (meth)acrylate component)

When the amount of hydrophilic functional groups is 4.80 mmol/g or more, there are many (meth)acryloyl groups that are reactive groups, so the reactivity becomes high and the sealing performance of the organic EL element is satisfactorily expressed, resulting in low The moisture permeability improves the reliability of the organic EL element and improves its flatness. When it is 7.60 mmol/g or less, moisture is difficult to be released from inside the sealant for an organic electroluminescent display element during a reliability test, moisture does not reach the organic light emitting material layer, and dark spots are unlikely to occur. From the viewpoint of reactivity and reliability, 4.80 to 7.60 mmol/g is preferable, and 5.00 to 7.10 mmol/g is more preferable.

This embodiment preferably contains (meth)acrylate other than the component (A) as the component (C). As component (C), one or more of the group consisting of monofunctional (meth)acrylates, bifunctional (meth)acrylates, and polyfunctional (meth)acrylates can be used. By using component (C), it is possible to adjust the amount of hydrophilic functional groups in the composition, and it is also possible to adjust the viscosity, inkjet applicability, and moisture permeability.

Here, the term "hydrophilic functional group" refers to one in which the maximum value of the difference in electronegativity among the atoms constituting the functional group is 0.6 or more. Such hydrophilic functional groups include (meth)acryloyl group, ester group, aldehyde group, nitro group, hydroxyl group, ethylene oxide group, propylene oxide group, ether group, amide group, cyclic amide group, sulfoxide group, carbonyl group, of the group consisting of carboxylic acid (salt) group, sulfonic acid (salt) group, sulfinic acid (salt) group, phosphonic acid (salt) group, phosphoric acid (salt) group, sulfobetaine group, carbobetaine group, phosphobetaine group One or more types are preferred.

The monofunctional (meth)acrylate of component (C) includes methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isooctyl (meth)acrylate. Acrylate, alkyl (meth)acrylate such as isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc., benzyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2, 4,5-tetramethylphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate (2-HPA ), 2-(meth)acryloyloxyhexahydrophthalic acid, 2-(meth)acryloyloxyethyl-2-hydroxypropylphthalic acid, EO (ethylene oxide) modified phenol (meth)acrylate, EO modified cresol (meth) Acrylate, EO modified nonylphenol (meth)acrylate, PO (propylene oxide) modified nonylphenol (meth)acrylate, ethoxylated-o-phenylphenol (meth)acrylate, m-phenoxybenzyl (meth)acrylate, 2-hydroxy-3-phenoxy Propyl (meth)acrylate, phenol ethylene oxide modified (meth)acrylate, phenol (2 mol ethylene oxide modified) (meth)acrylate, phenol (4 mol ethylene oxide modified) (meth)acrylate, paracumylphenol ethylene oxide modified (meth) Acrylate, nonylphenol ethylene oxide modified (meth)acrylate, nonylphenol (modified with 4 moles of ethylene oxide) (meth)acrylate, nonylphenol (modified with 8 moles of ethylene oxide) (meth)acrylate, nonylphenol (modified with 2.5 moles of propylene oxide) (meth) Acrylate, ethylene oxide-modified phthalic acid (meth)acrylate, phthalic acid monohydroxyethyl (meth)acrylate, etc. have one or more aromatic hydrocarbon-based cyclic structures (hereinafter sometimes referred to as aromatic hydrocarbon groups) in the molecule. ) monofunctional (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl ( Aliphatic hydrocarbon-based cyclic structures (hereinafter sometimes referred to as alicyclic hydrocarbon groups) such as meth)acrylate, isobornyl (meth)acrylate, and methoxylated cyclodecatriene (meth)acrylate. ) monofunctional (meth)acrylate, methoxylated cyclodecatriene (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy Butyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, ethoxycarbonylmethyl (meth)acrylate, 2-ethylhexylcarbitol (meth)acrylate, ethylene oxide modified succinic acid (meth)acrylate, ) acrylate, trifluoroethyl (meth)acrylate, (meth)acrylic acid, maleic acid, fumaric acid, ω-carboxy-polycaprolactone mono(meth)acrylate, (meth)acrylic acid dimer, β-(meth)acryloyloxy Examples include ethyl hydrogen succinate, n-(meth)acryloyloxyalkylhexahydrophthalimide, and 2-(1,2-cyclohexacarboximide)ethyl (meth)acrylate. As the monofunctional (meth)acrylate of component (C), a (meth)acrylate having a cyclic structure such as a heterocyclic structure such as a cyclic amide group, a tetrahydrofurfuryl group, or a piperidinyl group can be used.

As the bifunctional (meth)acrylate of component (C), dicyclopentanyl di(meth)acrylate, 2-ethyl-2-butyl-propanediol (meth)acrylate, neopentyl glycol-modified trimethylolpropanedi(meth)acrylate, Acrylate, stearic acid-modified pentaerythritol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, 2,2-bis(4-(meth)acryloxydiethoxyphenyl) Propane, 2,2-bis(4-(meth)acryloxypropoxyphenyl)propane, 2,2-bis(4-(meth)acryloxytetraethoxyphenyl)propane, 2-(1,2-cyclohexacarboximide) ) Ethyl (meth)acrylate, bisphenol A epoxy di(meth)acrylate, and the like. The bifunctional (meth)acrylate of component (C) is an ethoxylated bisphenol A di(meth)acrylate compound represented by the following structural formula, propoxylated bisphenol A di(meth)acrylate, propoxylated ethoxylated bisphenol A di( Examples include meth)acrylate.
In the following formula, each R is independently a hydrogen atom or a methyl group. Regarding m and n in the formula, m+n=2 to 10 is preferable.

The polyfunctional (meth)acrylate of component (C) includes trimethylolpropane tri(meth)acrylate, tris[(meth)acryloyloxyethyl]isocyanurate, dimethylolpropane tetra(meth)acrylate, and pentaerythritol tetra(meth)acrylate. ) acrylate, pentaerythritol ethoxytetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like.

The amount of hydrophilic functional groups in component (C) is preferably 3.00 to 15.00 mmol/g. If the amount of hydrophilic functional groups is 3.00 to 15.00 mmol/g, sufficient reactivity and reliability of the OLED device can be ensured. From the viewpoint of reactivity and OLED device reliability, the amount of hydrophilic functional groups in component (C) is preferably 4.00 to 15.00 mmol/g, more preferably 4.10 to 8.20 mmol/g, and 4.20 mmol/g. ˜7.60 mmol/g is even more preferred.

In terms of reactivity, OLED element reliability, and inkjet applicability, component (C) is an alkyl (meth)acrylate having 8 or more carbon atoms, (meth)acrylate having an alicyclic hydrocarbon group, or an aromatic hydrocarbon. Preferably, it is one or more of the group consisting of (meth)acrylates having groups. The alkyl (meth)acrylate having 8 or more carbon atoms is preferably one or more of the group consisting of isooctyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate, and lauryl (meth)acrylate is preferred. Acrylates are most preferred. Examples of (meth)acrylates having an alicyclic hydrocarbon group include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. One or more members of the group consisting of cyclopentenyloxyethyl (meth)acrylate, isobornyl (meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate are preferred, and dicyclopentanyl (meth)acrylate and dicyclopentanyloxyethyl One or more of the group consisting of (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyloxyethyl (meth)acrylate is more preferred. As the (meth)acrylate having an aromatic hydrocarbon group, ethoxylated-o-phenylphenol (meth)acrylate is preferred.

The content of component (A) is preferably 30 to 100 parts by mass, more preferably 30 parts by mass or more and less than 100 parts by mass, based on a total of 100 parts by mass of components (A) and (C). When the content of (A) is 30 parts by mass or more, inkjet coating properties, low moisture permeability, and reliability of the organic EL device are excellent. From the viewpoint of inkjet applicability, low moisture permeability, and reliability of organic EL devices, it is preferably 55 to 99 parts by weight, more preferably 60 to 95 parts by weight, and even more preferably 65 to 95 parts by weight.

The content of component (C) when present is preferably more than 0 parts by mass and 70 parts by mass or less, based on a total of 100 parts by mass of components (A) and (C). When the content of component (C) is 70 parts by mass or less, inkjet coating properties, low moisture permeability, and reliability of the organic EL device are excellent. The content of component (C) is preferably 1 to 45 parts by mass, more preferably 5 to 40 parts by mass, and still more preferably 5 to 35 parts by mass in terms of inkjet applicability, low moisture permeability, and reliability of the organic EL element. preferable.

As mentioned above, since OLED elements are easily deteriorated by moisture, it is preferable for the composition of this embodiment to have a low moisture content. From the viewpoint of reliability of the OLED element, the water content is preferably 90 ppm or less, more preferably 50 ppm or less, and even more preferably 30 ppm or less.

Although such water content can be measured using a commercially available moisture meter, it is common to use a Karl Fischer moisture meter.

Methods for reducing the water content include, but are not particularly limited to, the following methods.

(1) Remove moisture using a desiccant. After removing the water, the desiccant is separated by decantation or filtration. Desiccants are not particularly limited as long as they do not affect the resin composition, but include polymer adsorbents (molecular sieves, synthetic zeolites, alumina, silica gel, etc.), inorganic salts (calcium chloride, anhydrous magnesium sulfate, quicklime, anhydrous sodium sulfate, etc.). , anhydrous calcium sulfate, etc.), solid alkalis (sodium hydroxide, potassium hydroxide, etc.), and the like. (2) Heat under reduced pressure to remove moisture. (3) Purification by distillation under reduced pressure conditions. (4) Inert gas such as dry nitrogen or dry argon gas is blown into each component to remove moisture. (5) Remove moisture by freeze drying.

The water content may be reduced by reducing the water content for each component before mixing, or by reducing the water content after mixing each component. One or more types may be used in the water content reduction step. After the step of reducing the amount of water, it is preferable to handle the product under an inert gas atmosphere in order to prevent water from being reintroduced.

Further, as described above, since OLED elements are easily deteriorated by oxygen, it is preferable that the amount of dissolved oxygen be small in the composition of this embodiment. From the viewpoint of reliability of the OLED element, the amount of dissolved oxygen is preferably 20 ppm or less, more preferably 10 ppm or less. On the other hand, dissolved oxygen reacts with active radicals generated from the composition and generates inactive peroxide radicals, which has the effect of suppressing the thickening caused by polymerization of the composition, thereby improving storage stability. From this point of view, it is preferably 1 ppm or more, and more preferably 2 ppm or more.

Such dissolved oxygen amount can be measured by a titration method using a reagent, a diaphragm electrode method using a diaphragm, a fluorescence method using a fluorescent substance, or the like. Although the measuring method is not particularly limited, the diaphragm electrode method is simple and preferred.

Methods for reducing the amount of dissolved oxygen are not particularly limited, but include the following methods.

(1) Expose to reduced pressure conditions to remove oxygen. (2) Inert gas such as dry nitrogen or dry argon gas is blown into each component to remove oxygen. (3) Remove oxygen by exposing to low oxygen concentration.

The amount of dissolved oxygen may be reduced by reducing oxygen for each component before mixing, or by reducing oxygen after mixing each component. One or more types may be used in the step of reducing the amount of dissolved oxygen. After the step of reducing the amount of dissolved oxygen, it is preferable to handle the product under an inert gas atmosphere in order to prevent oxygen from being reintroduced.

In the composition of this embodiment, the (meth)acrylate is preferably a monomer from the viewpoint of inkjet ejection properties. Component (A) and component (C) are preferably monomers. The molecular weight of the monomer is preferably 1000 or less. In terms of inkjet ejectability, bifunctional (meth)acrylate oligomers/polymers and polyfunctional (meth)acrylate oligomers/polymers contain 3 parts by mass of (meth)acrylate containing component (A) and (C). It is preferably contained in an amount of 1 part by mass or less, more preferably 1 part by mass or less, and most preferably not contained. Oligomer/polymer refers to one or more of the group consisting of oligomers and polymers. Preferably, the molecular weight of the oligomer/polymer is greater than 1000.

In the composition of this embodiment, (D) an antioxidant can be used to improve storage stability. As antioxidants, methylhydroquinone, hydroquinone, octadecyl 3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, 2,2-methylene-bis(4-methyl-6-tert-butylphenol) ), catechol, hydroquinone monomethyl ether, mono-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, 2,5-di-tert-butyl-p-benzoquinone , picric acid, citric acid, phenothiazine, tert-butylcatechol, 2-butyl-4-hydroxyanisole, and 2,6-di-tert-butyl-p-cresol. It is preferable to use a combination of two or more kinds of antioxidants. Among these, phenolic antioxidants are preferred because they have great effects such as transparency and storage stability. Among the phenolic antioxidants, hindered phenolic antioxidants are preferred. Examples of hindered phenolic antioxidants include octadecyl 3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, 2,2-methylene-bis(4-methyl-6-tert-butylphenol) Preferably, one or more of the group consisting of octadecyl 3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate and 2,2-methylene-bis(4-methyl-6-tert- butylphenol) is more preferably contained. Examples of octadecyl 3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate include "Irganox 1076" manufactured by BASF Japan. Examples of 2,2-methylene-bis(4-methyl-6-tert-butylphenol) include "SUMILIZER MDP-S" manufactured by Sumitomo Chemical Co., Ltd. When containing octadecyl 3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate and 2,2-methylene-bis(4-methyl-6-tert-butylphenol), 3-[3, The content ratio of octadecyl 5-di-tert-butyl-4-hydroxyphenyl]propionate and 2,2-methylene-bis(4-methyl-6-tert-butylphenol) is 3-[3,5-di-tert-butylphenol). -butyl-4-hydroxyphenyl] octadecyl propionate and 2,2-methylene-bis(4-methyl-6-tert-butylphenol), in a mass ratio of tert-butyl-4-hydroxyphenyl] octadecyl propionate: 2,2-methylene-bis(4-methyl-6-tert-butylphenol) = 10-90: preferably 90-10, 25-75: 75-25 More preferred.

The content of the antioxidant is preferably 0.001 to 3 parts by weight, more preferably 0.01 to 2 parts by weight, based on a total of 100 parts by weight of components (A) and (C). When it is 0.001 parts by mass or more, storage stability is ensured, and when it is 3 parts by mass or less, good adhesiveness is obtained and it does not become uncured.

The composition of this embodiment can be used as a resin composition. The composition of this embodiment can be used as a photocurable resin composition. The composition of this embodiment can be used as a sealant for organic EL display elements.

Examples of the method of curing the composition by irradiating the composition with visible light or ultraviolet rays include a method of curing the composition by irradiating at least one of visible light or ultraviolet rays. Energy irradiation sources for irradiating visible light or ultraviolet rays include deuterium lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, low-pressure mercury lamps, xenon lamps, xenon-mercury hybrid lamps, halogen lamps, excimer lamps, Examples of energy irradiation sources include indium lamps, thallium lamps, LED lamps, and electrodeless discharge lamps. The composition of this embodiment is preferably cured at a wavelength of 380 nm or more, more preferably cured at a wavelength of 395 nm or more, and preferably cured at a wavelength of 395 nm, since it is difficult to damage the organic EL element. Most preferred. The wavelength of the energy irradiation source is preferably 500 nm or less because emitting infrared light increases the temperature of the irradiation part and may damage the organic EL element. As the energy irradiation source, an LED lamp whose emission wavelength is a single wavelength is preferable.

When curing the composition by irradiating it with visible light or ultraviolet rays, it is preferable to irradiate the composition with energy rays of 100 to 8000 mJ/cm ² at a wavelength of 395 nm to cure the composition. If it is 100 to 8000 mJ/cm ² , the composition will be cured and sufficient adhesive strength will be obtained. If it is 100 mJ/cm ² or more, the composition will be sufficiently cured, and if it is 8000 mJ/cm ² or less, it will not damage the organic EL element. The amount of energy for curing the composition is more preferably 300 to 2000 mJ/cm ² .

The transparency of the composition of this embodiment is as follows. When the thickness of the organic film is 1 μm or more and 10 μm or less, the spectral transmittance in the ultraviolet-visible region of 360 nm or more and 800 nm or less is preferably 95% or more, more preferably 97% or more, and most preferably 99% or more. If it is 95% or more, an organic EL device with excellent brightness and contrast can be provided.

It is preferable that there are 1 to 5 sets of the sealing layer made of the composition of the present embodiment, counting the inorganic/organic laminate as one set. This is because when there are six or more sets of inorganic/organic laminates, the sealing effect on the organic EL element is almost the same as when there are five sets. The thickness of the inorganic film of the inorganic/organic laminate is preferably 50 nm to 1 μm. The thickness of the organic film of the inorganic/organic laminate is preferably 1 to 15 μm, more preferably 3 to 10 μm. When the thickness of the organic film is 1 μm or more, it can completely cover particles generated during device formation and can be coated on the inorganic film while ensuring flatness. If the thickness of the organic film is 15 μm or less, moisture will not enter from the side surfaces of the organic film, improving the reliability of the organic EL device.

The sealing substrate is formed in close contact so as to cover the entire upper surface of the uppermost organic film of the sealing layer. Examples of this sealing substrate include the aforementioned substrates. Among these, substrates that are transparent to visible light are preferred. Among the substrates (transparent sealing substrates) that are transparent to visible light, one or more selected from the group consisting of glass substrates and plastic substrates are preferred, and glass substrates are more preferred.

The thickness of the transparent sealing substrate is preferably 1 μm or more and 1 mm or less, more preferably 10 μm or more and 800 μm or less, and most preferably 50 μm or more and 300 μm or less. By providing the transparent sealing substrate further above the sealing layer, it is possible to suppress the deterioration that progresses when the surface of the uppermost organic film comes into contact with gas, and it is possible to improve the barrier properties of the organic EL device.

Next, a method for manufacturing an organic EL device having such a configuration will be described. First, an anode patterned into a predetermined shape, an organic EL layer including a light emitting layer, and a cathode are sequentially formed on a first substrate by a conventionally known method to form an organic EL element. For example, when an organic EL device is used as a dot matrix display device, banks are formed to partition light emitting regions into a matrix, and an organic EL layer including a light emitting layer is formed in a region surrounded by the banks.

Next, on the substrate on which the organic EL element is formed, a film having a predetermined thickness is formed by a film forming method such as a PVD (Physical Vapor Deposition) method such as a sputtering method or a CVD method such as a plasma CVD (Chemical Vapor Deposition) method. A first inorganic film is formed. Thereafter, the composition of the present embodiment is deposited on the first inorganic film using a coating film forming method such as a solution coating method or a spray coating method, a flash vapor deposition method, an inkjet method, or the like. Among these, the inkjet method is preferred in terms of productivity. Thereafter, the composition is cured by irradiation with energy rays such as ultraviolet rays, electron beams, and plasma, and a first organic film is formed. Through the above steps, one set of inorganic/organic laminate is formed. The curing rate of the composition is not particularly limited as long as the effects of the present embodiment are achieved, but, for example, it is preferably 90% or more, more preferably 95% or more, as determined by the measurement method described below.

The process of forming the inorganic/organic laminate described above is repeated a predetermined number of times. However, for the last set, that is, the top layer of the inorganic/organic laminate, the composition is applied to the top surface of the inorganic film by a coating method, flash vapor deposition method, inkjet method, etc. so that the top surface is flat. Also good.

Next, a transparent sealing substrate is bonded to the surface of the substrate to which the composition is attached. Perform positioning when pasting. Thereafter, the composition of this embodiment present between the uppermost inorganic film and the transparent sealing substrate is cured by irradiating energy rays from the transparent sealing substrate side. As a result, the composition is cured to form the uppermost organic film, and the uppermost organic film and the transparent sealing substrate are bonded together. With the above steps, the method for manufacturing an organic EL device is completed.

After the composition is deposited on the inorganic film, it may be partially irradiated with energy rays to polymerize it. By doing so, when the transparent sealing substrate is placed, it is possible to prevent the composition serving as the uppermost organic film from deforming. The thickness of the inorganic film and the organic film may be the same for each inorganic/organic laminate, or may be different for each inorganic/organic laminate.

In the above description, a top emission type organic EL device was used as an example. This embodiment can also be applied to a bottom emission type organic EL device in which light generated in an organic EL layer is emitted from the substrate side.

The organic EL element of this embodiment can be used as a planar light source, a segment display device, or a dot matrix display device.

According to this embodiment, a sealing layer is formed to isolate the organic EL element formed on the first substrate from the outside air, and a transparent sealing substrate is further placed on the sealing layer. A sealing structure having sufficient water vapor and oxygen barrier properties for the EL element can be obtained. According to this embodiment, a sealing structure having sufficient adhesive strength between the transparent sealing substrate and the sealing layer can be obtained.

According to this embodiment, after the composition of this embodiment constituting the uppermost organic film of the sealing layer is attached, a transparent sealing substrate is placed without curing the composition, and then the composition is formed. Since the material is cured, the sealing layer and the transparent sealing substrate can be bonded together at the same time as the uppermost organic film constituting the sealing layer is formed. As a result, this embodiment has the effect that the process can be simplified compared to the case where the sealing layer and the transparent sealing substrate are bonded together with an adhesive.

The composition of this embodiment has a moisture permeability value of 350 g/m at a thickness of 100 μm, which is measured by exposing the cured product to an environment of 85° C. and 85% RH for 24 hours, in accordance with JIS Z 0208:1976. It is preferable that it is less than ^m2 . If the moisture permeability is 350 g/m ² or less, moisture will not reach the organic light-emitting material layer and dark spots will be less likely to occur.

According to this embodiment, it is possible to provide an encapsulant for an organic EL display element that can be easily applied by an inkjet method and has excellent reliability of OLED elements, transparency of a cured product, and barrier properties. According to this embodiment, it is possible to provide a method for manufacturing an organic EL display element using a sealant for an organic EL display element. The inkjet method is a method in which fine droplets are ejected from a nozzle and applied to an object without contact.

(Experiment Examples 1 to 17)
A composition was prepared and evaluated by the following method.

(Preparation of composition)
The materials shown in Table 1 were used. After mixing the materials in Table 2 and dehydrating them using molecular sieves (manufactured by Union Showa Co., Ltd. in the form of 5A pellets), the compositions were exposed for 72 hours or more in a glove box with an oxygen concentration of 5 ppm or less. Prepared. Using the obtained composition, E-type viscosity, water content, dissolved oxygen amount, moisture permeability, coating area expansion rate, curing rate, transparency, and organic EL evaluation were measured using the evaluation methods shown below. Ta. The results are shown in Table 2. The abbreviations shown in Table 1 were used for the composition names in Table 2.

[E type viscosity]
The viscosity of the composition was measured using an E-type viscometer (cone plate type: cone angle 1° 34', cone rotor radius 24 mm) at a temperature of 25° C. and a rotation speed of 100 rpm.

[Water content]
The water content of the composition was measured using Aquamicron AX (manufactured by Mitsubishi Chemical Corporation) as a Karl Fischer solution and a trace moisture measuring device CA-06 (manufactured by Mitsubishi Chemical Corporation).

[Dissolved oxygen amount]
The amount of dissolved oxygen in the composition was measured using a dissolved oxygen meter (manufactured by Iijima Electronics Co., Ltd., trade name: "DO Meter B-506 (diaphragm type galvanic cell type)").

[Light curing conditions]
In evaluating the cured physical properties of the composition, the composition was cured under the following light irradiation conditions. The composition was photocured using an LED lamp that emits light at a wavelength of 395 nm (UV-LED LIGHT SOURCE H-4MLH200-V1 manufactured by HOYA) under conditions of an integrated light intensity of 1,500 mJ/cm ² at a wavelength of 395 nm, and then cured. I got a body.

[Moisture permeability]
A sheet-like cured product with a thickness of 0.1 mm was produced under the above photocuring conditions, and calcium chloride (anhydrous) was added as a moisture absorbent according to JIS Z0208:1976 "Moisture permeability test method for moisture-proof packaging materials (cup method)". The measurement was carried out under conditions of an ambient temperature of 85° C. and a relative humidity of 85%.

Using an infrared spectrometer (manufactured by Thermo Scientific, Nicolet is5, DTGS detector, resolution 4 cm ^-1 ), infrared light was applied to the composition after curing and the composition before curing to the measurement sample. The infrared spectra were measured. In the obtained infrared spectra, the stretching vibration peak of the carbon-hydrogen bond of the methylene group observed around 2950 cm ^-1 , which does not change before and after curing, was used as an internal standard. From the peak area and the area before and after curing of the peak around 810 cm ^-1 , which is attributed to the peak of out-of-plane bending vibration of the carbon-hydrogen bond bonded to the carbon-carbon double bond of (meth)acrylate, the following formula The curing rate was calculated using
Curing rate (%) = [1-(Ax/Bx)/(Ao/Bo)] x 100
here,
Ao: represents the peak area before curing near 810 cm ^-1 .
Ax: represents the peak area after curing around 810 cm ^-1 .
Bo: represents the peak area before curing near 2950 cm ^-1 .
Bx: represents the peak area after curing around 2950 cm ⁻¹ .

〔transparency〕
The composition obtained in each experimental example was formed to a thickness of 10 μm between two 25 mm x 25 mm x 1 mm thick (mm thick) glass plates (alkali-free glass, Eagle A cured product was obtained by irradiating ultraviolet rays with a wavelength of 395 nm at an irradiation amount of 1500 mJ/cm ² . The spectral transmittance of the obtained cured product at 380 nm, 412 nm, and 800 nm was measured using an ultraviolet-visible spectrophotometer ("UV-2550" manufactured by Shimadzu Corporation), and the transparency was determined.

[Expansion rate of coating area]
The composition obtained in each experimental example was applied onto a 70 mm x 70 mm x 0.7 mm base material (alkali-free glass (Eagle '') to form a pattern of 4 mm x 4 mm x 10 μm. Before use, the alkali-free glass was cleaned using acetone and isopropanol, and then washed for 5 minutes using a UV ozone cleaning device UV-208 manufactured by Technovision. Immediately after pattern coating, the pattern was left to stand for 5 minutes at an ambient temperature of 23° C. and a relative humidity of 50%, and the flatness after inkjet coating was evaluated based on the expansion rate of the coating area (see the formula below). The smaller the enlargement rate of the coating area, the better the shape after coating was maintained and the better the position controllability, which was evaluated as more preferable.
(Expansion rate of coating area) = ((Contact area of the composition in contact with the substrate surface 5 minutes after pattern coating) / (Contact area of the composition in contact with the substrate surface immediately after pattern coating) )×100(%)

[Organic EL evaluation]

[Preparation of organic EL element substrate]
A 30 mm square glass substrate with an ITO electrode (thickness: 700 μm) was cleaned using acetone and isopropanol, respectively. Thereafter, the following compounds were sequentially deposited into a thin film using a vacuum evaporation method to form a 2 mm square organic EL element consisting of an anode/hole injection layer/hole transport layer/light emitting layer/electron injection layer/cathode. I got the board. The structure of each layer is as follows.
・Anode ITO, anode film thickness 150nm
・Hole injection layer 4,4',4''-tris {2-naphthyl(phenyl)amino}triphenylamine (2-TNATA)
・Hole transport layer N,N'-diphenyl-N,N'-dinaphthylbenzidine (α-NPD)
- Light-emitting layer Tris(8-hydroxyquinolinato)aluminum (metal complex material), thickness of the light-emitting layer is 1000 Å, and the light-emitting layer also functions as an electron transport layer.
・Electron injection layer lithium fluoride ・Cathode aluminum film thickness 150 nm

[Production of organic EL device]
Thereafter, a mask (cover) having a 10 mm x 10 mm opening was placed to cover the 2 mm x 2 mm organic EL element, and a SiN film was formed by plasma CVD. Next, the composition (organic film) obtained in each experimental example was applied to a thickness of 10 μm using the above inkjet apparatus under a nitrogen atmosphere so as to cover a 2 mm x 2 mm organic EL element, and the photocuring conditions were as follows. After curing this composition, a mask (cover) having an opening of 10 mm x 10 mm was installed so as to cover the entire cured product, and a SiN film was formed using a plasma CVD method. An EL display element was obtained.

The thickness of the formed SiN (inorganic film) was about 1 μm. Thereafter, a 30 mm x 30 mm x 25 μm transparent base-less double-sided tape was used to bond it to a 30 mm x 30 mm x 0.7 mm thick alkali-free glass (Eagle XG manufactured by Corning) to produce an organic EL element (organic EL evaluation). ).

〔initial〕
A voltage of 6 V was applied to the organic EL element immediately after fabrication, the light emitting state of the organic EL element was observed visually and with a microscope, and the diameter of the dark spot was measured.

〔durability〕
After exposing the organic EL device immediately after fabrication for 500 hours under the conditions of 85° C. and relative humidity of 85% by mass, a voltage of 6 V was applied, and the light emitting state of the organic EL device was observed visually and with a microscope. The diameter of the spot was measured.

The diameter of the dark spot can be taken as an index for evaluating the degree of penetration of the sealant into the pinhole of the passivation film and the degree to which water in the sealant is discharged as outgas. The diameter of the dark spot was evaluated as preferably 300 μm or less, more preferably 50 μm or less, and most preferably no dark spot.

The following was found from the above experimental example.

The composition according to the present embodiment can provide a composition that is excellent in reliability of an organic EL element, high-precision inkjet ejection properties, shape retention after inkjet coating, and excellent in low moisture permeability.

It contains an alkanediol di(meth)acrylate having 4 to 20 carbon atoms as the component (A) and a photopolymerization initiator as the component (B), and the amount of hydrophilic functional groups per (meth)acrylate is from 4.80 to When the content was within the range of 7.60 mmol/g, reliability, inkjet ejection properties, flatness after coating, and low moisture permeability were excellent. Furthermore, the diameter of the dark spots that appeared initially was also small (Experimental Examples 1 to 12).

On the other hand, if the amount of hydrophilic functional groups does not satisfy the range of 4.80 to 7.60 mmol/g, not only the diameter of the dark spot that occurs initially will be large, but also the moisture permeability will be high, causing reliability problems. (Experimental Examples 13 to 17).

Furthermore, if an alkanediol di(meth)acrylate having a carbon number of 4 or more and 20 or less is not used, the expansion rate of the coating area is small, and there are problems with inkjet ejection properties and flatness after coating, as well as high moisture permeability. There was a problem with reliability (Experiment Example 15).

The composition of the present embodiment has excellent ejection properties by highly accurate inkjet and flatness after inkjet application, has low moisture permeability and transparency, and does not deteriorate organic EL elements. In this embodiment, inkjet coating can be performed in a short time. The composition of the present embodiment is suitable for adhesion of electronic products, particularly display parts such as organic EL, electronic parts such as image sensors such as CCD and CMOS, and even element packages used in semiconductor parts. can. It is particularly suitable for adhesives for sealing organic EL devices, and satisfies the characteristics required for adhesives for packaging devices such as organic EL devices.

The above-mentioned composition is one aspect of the present embodiment, and a sealant for an organic EL element, a cured body, a covering body, a bonded body, an organic EL device, a display, and the production thereof using the composition according to the present embodiment. The methods and the like also have similar configurations and effects.

Claims (21)

Contains (A) alkanediol di(meth)acrylate having 4 to 20 carbon atoms and (B) a photopolymerization initiator, and the amount of hydrophilic functional groups per (meth)acrylate is 5.00 to 7.60 mmol/ in the range of g ,
A sealing agent for an organic electroluminescent display element having a water content of 90 ppm or less . (C) further contains a (meth)acrylate other than the component (A), with the component (A) being 30 parts by mass or more and less than 100 parts by mass, based on a total of 100 parts by mass of the components (A) and (C); The encapsulant for an organic electroluminescent display element according to claim 1, containing 0.05 to 6 parts by mass of component (B) and more than 0 parts by mass and 70 parts by mass or less of component (C). The encapsulant for organic electroluminescent display elements according to claim 2, wherein the amount of hydrophilic functional groups per (meth)acrylate in component (C) is 3.00 to 15.00 mmol/g. The sealant for organic electroluminescent display elements according to any one of claims 1 to 3, which has a viscosity of 2 mPa·s or more and 50 mPa·s or less as measured by an E-type viscometer at 25°C. The encapsulant for organic electroluminescent display elements according to any one of claims 1 to 4, which has a water content of 50 ppm or less. The sealant for an organic electroluminescent display element according to any one of claims 1 to 5, wherein the amount of dissolved oxygen is 1 ppm or more and 20 ppm or less. The encapsulant for an organic electroluminescent display element according to any one of claims 1 to 6, which does not contain a difunctional (meth)acrylate oligomer/polymer and a polyfunctional (meth)acrylate oligomer/polymer. The encapsulant for organic electroluminescent display elements according to any one of claims 1 to 7, wherein component (A) is an alkanediol di(meth)acrylate having 12 to 16 carbon atoms. The encapsulant for organic electroluminescent display elements according to any one of claims 1 to 8, wherein component (A) is 1,12-dodecanediol di(meth)acrylate. Component (C) is one or more of the group consisting of alkyl (meth)acrylates having 8 or more carbon atoms, (meth)acrylates having an alicyclic hydrocarbon group, and (meth)acrylates having an aromatic hydrocarbon group. The encapsulant for organic electroluminescent display elements according to any one of claims 2 to 9. The encapsulant for organic electroluminescent display elements according to any one of claims 2 to 10, wherein component (C) contains lauryl (meth)acrylate. Component (C) is dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyloxy The encapsulant for an organic electroluminescent display element according to any one of claims 2 to 11, containing one or more members of the group consisting of ethyl (meth)acrylate. The encapsulant for organic electroluminescent display elements according to any one of claims 2 to 12, wherein component (C) contains ethoxylated-o-phenylphenol (meth)acrylate. The encapsulant for an organic electroluminescent display element according to any one of claims 1 to 13, wherein the component (B) is an acylphosphine oxide derivative. A cured product obtained by curing the sealant for organic electroluminescent display elements according to any one of claims 1 to 14. A bonded body bonded with the sealant for organic electroluminescent display elements according to any one of claims 1 to 14. The method for curing a sealant for an organic electroluminescent display element according to any one of claims 1 to 14, characterized in that curing is performed using a wavelength of 380 nm or more and 500 nm or less. The method for curing a sealant for an organic electroluminescent display element according to any one of claims 1 to 14, characterized in that curing is performed using an LED lamp with an emission wavelength of 395 nm. A method for applying a sealant for an organic electroluminescent display element according to any one of claims 1 to 14, which is applied using an inkjet method. An organic EL device comprising the sealant for an organic electroluminescent display element according to any one of claims 1 to 14. A display comprising the sealant for an organic electroluminescent display element according to any one of claims 1 to 14.