TW202340285A - Encapsulating material for organic-electroluminescent display element - Google Patents

Abstract

An encapsulating material for organic-electroluminescent display elements which comprises (A) an alkanediol(C4-20) di(meth)acrylate and (B) a photopolymerization initiator and has a content of hydrophilic functional groups in the range of 4.80-7.60 mmol per gram of the (meth)acrylate.

Description

Sealant for organic electroluminescent display elements

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

Organic electroluminescence (EL) devices (also called OLED devices) are attracting attention as devices that emit light with high brightness. However, OLED elements are degraded by oxygen or moisture, resulting in reduced light-emitting properties.

In order to solve such problems, technology to seal organic EL elements and prevent deterioration caused by moisture is being studied. An example is a sealing method using a sealing material made of sintered glass (see Patent Document 1).

An organic electroluminescence display element has been proposed, in which the sealing layer is a laminate in which at least a shielding layer, a resin layer, and a shielding layer are formed in this order (see Patent Document 2); and an organic EL device is provided with: a sealing layer and an interactive layer. An inorganic film and an organic film for sealing an organic EL element are accumulated; and a sealing glass substrate is closely adhered to the uppermost organic film of the sealing layer and arranged to cover the entire upper surface of the uppermost organic film (see Patent Document 3) .

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

[Prior technical literature] [Patent Document] [Patent Document 1] Japanese Patent Application Publication No. 10-74583 [Patent Document 2] Japanese Patent Application Publication No. 2001-307873 [Patent document 3] Japanese Patent Application Publication No. 2009-37812 [Patent Document 4] Japanese Patent Application Publication No. 2014-225380 [Patent Document 5] Japanese Patent Application Publication No. 2012-190612 [Patent Document 6] Japanese Patent Application Publication No. 2014-229496 [Patent Document 7] Japanese Patent Application Publication No. 2014-196387 [Patent document 8] Japanese Patent Application Publication No. 2014-193970 [Patent document 9] Japanese Patent Application Publication No. 2014-193971 [Patent document 10] WO2014/157642 [Patent Document 11] US2017/0062762 Publication No. [Patent Document 12] Japanese Special Publication No. 2017-536429 [Patent Document 13] Japanese Special Publication No. 2018-504735 [Patent Document 14] WO2016/068415

[Problem to be solved by the invention] However, the conventional technology described in the above-mentioned documents still has room for improvement from the following point of view.

In Patent Document 1, during mass production, a method is adopted in which an organic EL element is sandwiched between a base material with low moisture permeability, such as glass, and the outer peripheral portion is sealed. In this case, the structure becomes a hollow sealing structure, so moisture cannot be prevented from intruding into the interior of the hollow sealing structure, leading to the problem of deterioration of the organic EL element.

In Patent Documents 2 and 3, the organic film is formed by evaporation, so 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, the following problems arise: particles generated during device formation cannot be completely covered, and it is difficult to coat the inorganic film while maintaining flatness.

Patent Document 4 proposes the use of a sealant using an epoxy-based material. However, this material requires heating to harden, so it can cause damage to organic EL elements, which is also a problem from the viewpoint of productivity. Patent Document 5 proposes a photo-curable sealant using an epoxy-based material. However, this material is cured by UV light, so UV light can cause damage to organic EL elements, which is also a problem from the perspective of productivity.

In Patent Documents 6 to 10 and 12 to 14, it is described that the necessary characteristic of such a sealing material is to reduce the water vapor transmittance. However, there is a case where the sealing material itself penetrates through the pinholes of the passivation film and reduces the reliability of the organic EL element. problem, and no countermeasures are documented for this problem.

Although Patent Document 11 describes the use of cyclic monofunctional (meth)acrylate, it does not solve the problem of unreacted products outgassing and causing poor luminescence of organic EL elements.

In the above-mentioned conventional technology, it has been a problem so far that it is impossible to achieve both the ejection properties when using inkjet and the reliability of organic EL elements.

[Technical means to solve the problem] The present invention was made in view of the above-mentioned circumstances, and for example, an object thereof is to provide a composition excellent in coating properties and low moisture permeability for use in sealing organic EL elements.

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

[1] A sealant for organic electroluminescent display elements, containing (A) alkylene glycol di(meth)acrylate with a carbon number of 4 to 20 and less than 20, and (B) a photopolymerization initiator, each (meth)acrylic acid The amount of hydrophilic functional groups of the ester is in the range of 4.80 to 7.60 mmol/g.

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

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

[4] The sealing compound for organic electroluminescent display elements according to any one of [1] to [3], wherein the viscosity measured with an E-type viscometer at 25°C is 2 mPa･s or more and 50 mPa･s or less.

[5] The sealing compound for organic electroluminescence display elements according to any one of [1] to [4], wherein the water content is 90 ppm or less.

[6] The sealing compound for organic electroluminescence display elements 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 sealing compound for organic electroluminescent display elements according to any one of [1] to [6], which does not contain bifunctional (meth)acrylate oligomer/polymer and polyfunctional (methyl) Acrylate oligomers/polymers.

[8] The sealing compound for organic electroluminescent display elements according to any one of [1] to [7], wherein the component (A) is an alkylene glycol di(meth)acrylate having a carbon number of 12 to 16.

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

[10] The sealing compound for organic electroluminescence display elements according to any one of [2] to [9], wherein the component (C) is an alkyl (meth)acrylate having a carbon number of 8 or more and having an alicyclic formula One or more types of the group consisting of (meth)acrylate having a hydrocarbon group and (meth)acrylate having an aromatic hydrocarbon group.

[11] The sealing compound for organic electroluminescence display elements according to any one of [2] to [10], wherein the component (C) contains lauryl (meth)acrylate.

[12] The sealing compound for organic electroluminescent display elements according to any one of [2] to [11], wherein the component (C) contains dicyclopentyl (meth)acrylate, dicyclopentyl (meth)acrylate, 1 of the group consisting of amyloxyethyl ester, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentyloxyethyl (meth)acrylate More than one species.

[13] The sealing compound for organic electroluminescence display elements according to any one of [2] to [12], wherein the component (C) contains ethoxylated o-phenylphenol (meth)acrylate.

[14] The sealing compound for organic electroluminescent display elements according to any one of [1] to [13], wherein the component (B) is a acylphosphine oxide derivative.

[15] A hardened body obtained by hardening the sealing compound for organic electroluminescence display elements according to any one of [1] to [14].

[16] A bonded body formed by bonding the organic electroluminescence display element sealant according to any one of [1] to [14].

[17] A method for curing a sealant for an organic electroluminescent display element, the sealant for an organic electroluminescent display element being the sealant for an organic electroluminescent display element described in any one of [1] to [14], and Use wavelengths above 380nm and below 500nm for hardening.

[18] A method for curing a sealant for an organic electroluminescent display element, the sealant for an organic electroluminescent display element being the sealant for an organic electroluminescent display element described in any one of [1] to [14], and Use an LED light with a wavelength of 395nm for hardening.

[19] A method of coating a sealant for an organic electroluminescent display element, the sealant for an organic electroluminescent display element being the sealant for an organic electroluminescent display element described in any one of [1] to [14], and Coating using inkjet method.

[20] An organic EL device including the sealing compound for organic electroluminescence display elements according to any one of [1] to [14].

[twenty one] A display including the sealing compound for organic electroluminescence display elements according to any one of [1] to [14].

[Invention effect] The sealant according to the present invention has excellent dischargeability when using inkjet, and can exhibit the effects of excellent reliability, coating properties, and low moisture permeability of the obtained organic EL element.

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

The numerical ranges described in this specification include upper and lower limits unless otherwise specified. In this specification, unless otherwise specified, the definitions are as follows. (Meth)acrylate means acrylate or methacrylate, and descriptions such as "(meth)acryloxy" or "(meth)acrylamide" also have the same meaning. "Monofunctional (meth)acrylate" refers to a (meth)acrylate having one (meth)acrylyl group, and "bifunctional (meth)acrylate" refers to a (meth)acrylate having two (meth)acryl groups. Cyl (meth)acrylate. "Polyfunctional (meth)acrylate" refers to (meth)acrylate having three or more (meth)acrylyl groups and does not include bifunctional (meth)acrylate.

Hereinafter, a top-emission organic EL device that emits light from the side opposite to a substrate on which an organic EL element is formed will be described as an example. A top-emission organic EL device has the following structure formed in sequence: an organic EL element, in which an anode, an organic EL layer containing a light-emitting layer, and a cathode are sequentially laminated on a substrate; a sealing layer, which consists of an inorganic film covering the entire organic EL element It is composed of a laminated film with an organic film; and a sealing substrate is provided on the sealing layer.

As the substrate, various substrates such as glass substrates, silicon substrates, and plastic substrates can be used. Among these, one or more types from the group consisting of a glass substrate and a plastic substrate is preferred, and a glass substrate is more preferred.

Examples of plastics used for the plastic substrate include polyimide, polyetherimide, polyethylene terephthalate, polyethylene naphthalate, polyoxadiazole, and aromatic polyamide. Polybenzimidazole, polybenzodithiazole, polybenzoxazole, polythiazole, polyparastyrene, polymethylmethacrylate, polystyrene, polycarbonate, polycyclic olefin, and polyacrylic acid, etc. Among them, polyimide, polyetherimide, polyethylene terephthalate, and polynaphthalenedicarboxylic acid are preferred in terms of low moisture permeability, low oxygen permeability, and excellent heat resistance. One or more of the group consisting of ethylene glycol, polyoxadiazole, aromatic polyamide, polybenzimidazole, polybenzobithiazole, polybenzoxazole, polythiazole, and polyparastyrene, From the viewpoint of high transmittance of energy rays such as ultraviolet rays or visible rays, a group consisting of polyimide, polyetherimide, polyethylene terephthalate, and polyethylene naphthalate is more preferred. 1 or more of them.

As the anode, a conductive metal oxide film or a translucent metal film with a relatively large work function (preferably a work function greater than 4.0 eV) or the like is generally used. Examples of the anode material include metal oxides such as indium tin oxide (hereinafter referred to as ITO) and tin oxide, metals such as gold (Au), platinum (Pt), silver (Ag), and copper (Cu), or materials containing Organic transparent conductive films such as at least one of these alloys, polyaniline or its derivatives, polythiophene or its derivatives, etc. The anode can be formed by two or more layers as needed. The appropriate anode film thickness can be selected by considering conductivity (light transmittance in the case of bottom emission type). The anode film thickness is preferably 10 nm to 10 μm, more preferably 20 nm to 1 μm, and most preferably 50 nm to 500 nm. Examples of anode manufacturing methods include vacuum evaporation, sputtering, ion plating, and electroplating. In the case of the top emission type, a reflective film may be provided under the anode to reflect light emitted from the substrate side.

The organic EL layer contains at least a light-emitting layer made of organic matter. This light-emitting layer contains a light-emitting material. Examples of the luminescent material include organic substances (low molecular compounds or polymer compounds) that emit fluorescence or phosphorescence. The light emitting layer may further contain dopant materials. Examples of organic substances include chromium-based materials, metal complex-based materials, polymer materials, and the like. Dopant material is a material doped into organic matter for the purpose of improving the luminous efficiency of organic matter or changing the wavelength of luminescence. The thickness of the light-emitting layer composed of these organic substances and optional dopants is usually 2 to 200 nm.

(Pigment-based materials) Examples of the pigment-based material include methamphetamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoquinoline derivatives, and distyryl derivatives. Benzene derivatives, distyryl aryl derivatives, pyrrole derivatives, thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumarylamine derivatives substances, oxadiazole dimers, pyrazoline dimers, etc.

(metal complex material) Examples of metal complex-based materials include metal complexes having emission originating from triplet excited states, such as iridium complexes and platinum complexes, aluminum hydroxyquinoline complexes, and benzohydroxyquinoline beryllium complexes. Metal complexes such as benzoxazolyl zinc complex, benzothiazole zinc complex, azomethyl zinc complex, porphyrin zinc complex, europium complex, etc. Examples of metal complexes include rare earth metals such as terium (Tb), europium (Eu), and dysprosium (Dy) as the central metal, aluminum (Al), zinc (Zn), beryllium (Be), etc., and are coordinated The base includes metal complexes having an oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure, etc. Among these, a metal complex in which the central metal has aluminum (Al) and the ligand has a quinoline structure or the like is preferred. Among metal complexes in which the central metal has aluminum (Al) and the ligand has a quinoline structure or the like, tris(8-hydroxyquinoline)aluminum is preferred.

(Polymer Materials) Examples of polymer materials include polyparastyrene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluoroethylene derivatives, polyvinylcarbazole derivatives, and Substances that polymerize the above-mentioned pigments or metal complex-based light-emitting materials.

Among the above-mentioned luminescent materials, examples of materials that emit blue light include distyrylaryl derivatives, oxadiazole derivatives, polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluoride derivatives. and such polymers, etc. Among these, polymer materials are preferred. Among the polymer materials, one or more types from the group consisting of polyvinylcarbazole derivatives, polyp-phenylene derivatives, and polyfluoride derivatives is preferred.

Examples of materials that emit green light include quinacridone derivatives, coumarin derivatives, polyparastyrene derivatives, polyfluoroethylene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among the polymer materials, one or more types from the group consisting of polyparastyrene derivatives and polyfluoride derivatives is preferred.

Examples of materials that emit red light include coumarin derivatives, thiophene ring compounds, polyparastyrene derivatives, polythiophene derivatives, polyfluoroethylene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among the polymer materials, one or more types from the group consisting of polyparastyrene derivatives, polythiophene derivatives, and polyfluoroethylene derivatives is preferred.

(dopant material) Examples of dopant materials include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squarylium derivatives, porphyrin derivatives, and styrene-based dyes. , condensed tetraphenyl derivatives, pyrazole derivatives, decacyclones, and phenoxazones, etc.

In addition to the light-emitting layer, the organic EL layer may be suitably provided with a layer provided between the light-emitting layer and the anode, and a layer provided between the light-emitting layer and the cathode. First, examples of the layer provided between the light-emitting layer and the anode include a hole injection layer that improves hole injection efficiency from the anode, or a hole injection layer that transports holes injected from the anode or the hole injection layer to the light-emitting layer. Transport layer, etc. Examples of the layer provided between the light-emitting layer and the cathode include an electron injection layer that improves electron injection efficiency from the cathode, an electron transport layer that transports electrons injected from the cathode or the electron injection layer to the light-emitting layer, and the like.

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

(hole transport layer) Examples of materials constituting the hole transport layer include polyvinylcarbazole or derivatives thereof, polysiloxane or derivatives thereof, polysiloxane derivatives having aromatic amines in side chains or main chains, and pyrazoline derivatives. compounds, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, benzidine derivatives, polyaniline or its derivatives, polythiophene or its derivatives, polyarylamine or its derivatives, polypyrrole Or its derivatives, poly(p-phenylene vinylene) or its derivatives, poly(2,5-thienylene vinylene) or its derivatives, etc. Examples of benzidine derivatives include N,N'-diphenyl-N,N'-dinaphthylbenzidine and the like.

When the hole injection layer or hole transport layer has the function of preventing electron transport, the hole transport layer or hole injection layer is also called an electron blocking layer.

(electron transport layer) As a material constituting the electron transport layer. Examples include oxadiazole derivatives, anthraquinone dimethane or its derivatives, benzoquinone or its derivatives, naphthoquinone or its derivatives, anthraquinone or its derivatives, tetracyanoanthraquinodimethane or its derivatives , quinone derivatives, diphenyldicyanoethylene or its derivatives, di-p-benzoquinone derivatives, 8-hydroxyquinoline or its derivatives, polyquinoline or its derivatives, polyquinoxaline or its derivatives substances, and polypropylene or its derivatives, etc. Examples of derivatives include metal complexes and the like. Among these, 8-hydroxyquinoline or its derivatives is preferred. Among 8-hydroxyquinoline or its derivatives, tris(8-hydroxyquinoline)aluminum is preferred from the viewpoint that it is contained in the light-emitting layer and can be used as an organic substance that emits fluorescence or phosphorescence.

(Electron injection layer) As the electron injection layer, depending on the type of the light-emitting layer, there can be mentioned an electron injection layer composed of a single-layer structure of a calcium (Ca) layer; or a metal of group IA and group IIA of the periodic table with a work function of 1.5 to 3.0 eV. An electron injection layer composed of a layered structure consisting of one or more types of metals and oxides, halides, and carbon oxides of the metal and a Ca layer. Examples of Group IA metals of the periodic table with a work function of 1.5 to 3.0 eV or their oxides, halides, and carbon oxides include lithium (Li), lithium fluoride, sodium oxide, lithium oxide, and lithium carbonate. Examples of metals from Group IIA of the periodic table having a work function of 1.5 to 3.0 eV or their oxides, halides, and carbon oxides include strontium (Sr), magnesium oxide, magnesium fluoride, strontium fluoride, and barium fluoride. Strontium oxide, magnesium carbonate, etc.

When the electron transport layer or electron injection layer has the function of blocking hole transport, the electron transport layer or electron injection layer is also called a hole blocking layer.

As the cathode, a transparent or translucent material that has a small work function (preferably has a work function of less than 4.0 eV) and is easy to inject electrons into the light-emitting layer is preferred. Examples of cathode materials 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) ), ytterbium (Tb), ytterbium (Yb) and other metals, or alloys composed of two or more of the above metals, or one or more of these with gold (Au), silver (Ag), platinum ( Pt), copper (Cu), chromium (Cr), manganese (Mn), titanium (Ti), cobalt (Co), nickel (Ni), tungsten (W), tin (Sn) Alloys, or graphite or graphite interlayer compounds, or metal oxides such as ITO, tin oxide, etc.

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

The layers disposed between the light-emitting layers and the anode, and between the light-emitting layers and the cathode can be appropriately selected according to the required performance of the organic EL device to be manufactured. For example, the organic EL element structure used in this embodiment may have any one of the following layer structures (i) to (xv). (i) Anode/hole transport layer/luminescent layer/cathode (ii) Anode/light-emitting layer/electron transport layer/cathode (iii) Anode/hole transport layer/luminescent layer/electron transport layer/cathode (iv) Anode/hole injection layer/light-emitting layer/cathode (v) Anode/light-emitting layer/electron injection layer/cathode (vi) Anode/hole injection layer/light-emitting layer/electron injection layer/cathode (vii) Anode/hole injection layer/hole transport layer/light-emitting layer/cathode (viii) Anode/hole transport layer/light-emitting layer/electron injection layer/cathode (ix) Anode/hole injection layer/hole transport layer/light-emitting layer/electron injection layer/cathode (x) Anode/hole injection layer/light-emitting layer/electron transport layer/cathode (xi) Anode/light-emitting layer/electron transport layer/electron injection layer/cathode (xii) Anode/hole injection layer/light-emitting layer/electron transport layer/electron injection layer/cathode (xiii) Anode/hole injection layer/hole transport layer/luminescent layer/electron transport layer/cathode (xiv) Anode/hole transport layer/luminescent layer/electron transport layer/electron injection layer/cathode (xv) Anode/hole injection layer/hole transport layer/luminescent layer/electron transport layer/electron injection layer/cathode (Here, "/" means that each layer is adjacent and stacked. The same applies below.)

The sealing layer is provided to prevent gases such as water vapor or oxygen from contacting the organic EL element, or to seal the organic EL element with a layer having high barrier properties against the gases. The sealing layer alternately forms an inorganic film and an organic film from bottom to top. The inorganic/organic layered body can be formed by repeating it 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 or oxygen present in the environment in which the organic EL device is installed. 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 films, SiO films, SiON films, Al ₂ O ₃ films, and AlN films, or laminated films thereof.

The organic film of the inorganic/organic laminate is provided in order to cover defects such as pinholes formed in the inorganic film or to provide surface flatness. The organic film is formed in a narrower area than the inorganic film formation area. The reason for this is that if the organic film is formed to be the same as or wider than the inorganic film formation area, the exposed area of the organic film will deteriorate. However, the uppermost organic film formed on the uppermost layer of the entire sealing layer is formed in almost the same region as the inorganic film formation region. Then, the upper surface of the sealing layer is planarized. As the organic film, a composition having good adhesion to the above-mentioned inorganic film is used.

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

The viscosity of the composition of this 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. When it is difficult to eject ink, heat the inkjet head appropriately. If the viscosity is 2 mPa･s or more, the applied sealant for organic EL display elements will not flow out of the organic EL display element before hardening, and will not flow into pinholes on the inorganic film, improving the reliability of the OLED element. If the viscosity is 50 mPa･s or less, inkjet coating becomes easier. The viscosity of the composition is preferably 5mPa･s～30mPa･s.

The composition of this embodiment is a (meth)acrylic resin composition containing (A) alkylene glycol di(meth)acrylate having a carbon number of 4 to 20 and 20 or less, and (B) a photopolymerization initiator. In addition, when the carbon number of the main chain (alkylene glycol, etc.) is described in this specification, the carbon number of the (meth)acrylate part is not included.

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

(A) Alkanediol di(meth)acrylate having 4 to 20 carbon atoms (alkane is a chain compound and a saturated hydrocarbon) includes 1,2-butanediol di(meth)acrylate , 1,3-butanediol di(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, 1,7-octanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate Meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,11-undecanediol di(meth)acrylate Acrylate, 1,12-dodecanediol di(meth)acrylate, 1,13-tridecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate ) acrylate, 1,15-pentadecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,17-heptadecanediol di(meth)acrylate base) acrylate, 1,18-octadecanediol di(meth)acrylate, 1,19-nonadecanediol di(meth)acrylate, 1,20-eicosanediol di(meth)acrylate Meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2,4-diethyl-1,5-pentanediol di(meth)acrylate, and Neopentyl glycol di(meth)acrylate, etc. (A) Alkanediol di(meth)acrylate having 4 to 20 carbon atoms (alkane is a cyclic compound) includes 1,2-cyclohexanediol di(meth)acrylate, 1, 3-Cyclohexanediol di(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate (Meth)acrylate, hydrogenated bisphenol A di(meth)acrylate, etc. From the viewpoint of reliability of OLED elements, among alkylene glycol di(meth)acrylates with a carbon number of 4 to 20, those with a larger number of carbon atoms in the main chain are preferred. However, the composition may deteriorate during storage. It will crystallize and produce crystallized products, which poses storage stability issues. From the viewpoint of reliability, moisture permeability, and storage stability of the OLED element, the carbon number is preferably 6 or more and 18 or less, more preferably 9 or more and 16 or less, still more preferably 12 or more and 16 or less, and most preferably 12. Among the components (A), 1,12-dodecanediol di(meth)acrylate is preferred. Examples of the component (A) include, for example, the trade name "1.9ND-A" manufactured by Kyeisha Chemical Co., Ltd., or the trade name "SR262" manufactured by Sartoma Co., Ltd.

(B) The photopolymerization initiator is sensitized by active light of visible light or ultraviolet light and used to promote photohardening of the resin composition. As the photopolymerization initiator, a photoradical polymerization initiator is preferred. Examples of photoradical polymerization initiators include benzophenone and its derivatives, diphenylethylenedione and its derivatives, anthraquinone and its derivatives, benzoin, benzoin methyl ether, and benzoin ethyl. Ether, benzoin propyl ether, benzoin isobutyl ether, benzyl dimethyl ketal and other benzoin derivatives, diethoxy acetophenone, 4-tertiary butyltrichloroacetophenone and other acetophenone derivatives , ethyl 2-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, diphenyl disulfide, thioxanthone and its derivatives, camphorquinone, 7,7-dimethyl-2,3- Bis-oxybicyclo[2.2.1]heptane-1-carboxylic acid, 7,7-dimethyl-2,3-bis-oxybicyclo[2.2.1]heptane-1-carboxy-2-bromo Ethyl ester, 7,7-dimethyl-2,3-di-oxybicyclo[2.2.1]heptane-1-carboxy-2-methyl ester, 7,7-dimethyl-2,3- Camphorquinone derivatives such as bicyclo[2.2.1]heptane-1-carboxylic acid chloride, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1 -Ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1 and other α-aminophenanone derivatives, benzyldiphenylphosphine Oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, benzyldiethoxyphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide Dimethoxyphenylphosphine oxide, 2,4,6-trimethylbenzyldiethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)- Phenylphosphine oxide and other acylphosphine oxide derivatives, phenyl-glyoxylic acid-methyl ester, oxy-phenyl-acetic acid 2-[2-side oxy-2-phenyl-acetyloxy- Ethoxy]-ethyl ester, and oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, etc. The photopolymerization initiator can be used in combination of 1 or more types. Among these, only visible light of 390 nm or above can be used for curing, and from the viewpoint of curing without causing damage to organic electroluminescent display elements, acylphosphine oxide derivatives are preferred. From the viewpoint that it does not reduce the transmittance of visible light when used as a display and can be cured using only light above 395 nm, 2,4,6-trimethylbenzyl is the most suitable among the acylphosphine oxide derivatives. Cyl-diphenyl-phosphine oxide. Examples of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide include "Irgacure TPO" manufactured by BASF Japan Co., Ltd. and the like.

The content of the (B) photopolymerization initiator is preferably 0.05 to 6 parts by mass, more preferably 0.5 to 4 parts by mass, based on 100 parts by mass of the total of component (A) and optionally used component (C). More preferably, it is 2 to 3.9 parts by mass, and most preferably 2.2 to 3.5 parts by mass. If the content of component (C) is 0.05 parts by mass or more, the hardening acceleration effect can be reliably obtained, and if it is 6 parts by mass or less, the visible light transmittance will not be reduced when used in displays.

In the (meth)acrylic resin composition of this embodiment, the amount of hydrophilic functional groups per (meth)acrylic acid ester contained must be 4.80 to 7.60 mmol/g. The amount of hydrophilic functional groups of the (meth)acrylic resin composition is calculated by the following formula: (A) component and the amount of hydrophilic functional groups per (meth)acrylate when component (C) is present. Finally, the product of multiplying the amount of hydrophilic functional groups of each material by the mass fraction of the individual material is calculated, and the sum is used as the amount of hydrophilic functional groups of the (meth)acrylic resin composition, and the mass fraction of the individual material is calculated. The ratio is shown by the following formula in the compounded (meth)acrylic resin composition. When calculating the mass fraction in the material, the total amount of (meth)acrylate is taken as 100 parts by mass. (In the aforementioned formula, material refers to each (meth)acrylate component) (In the above formula, the material refers to each (meth)acrylate component) If the amount of the above-mentioned hydrophilic functional groups is 4.80 mmol/g or more, there will be more (meth)acryl groups that are reactive groups, so the reaction will be enhanced. It can fully demonstrate the sealing performance of organic EL elements, and because of its low moisture permeability, it improves the reliability of organic EL elements and has good flatness. If it is 7.60 mmol/g or less, in the reliability test, moisture will not be easily released from the inside of the sealant for organic electroluminescent display elements, and the moisture will not reach the organic light-emitting material layer, and dark spots will not easily occur. From the viewpoint of reactivity and reliability, 4.80 to 7.60 mmol/g is preferred, and 5.00 to 7.10 mmol/g is more preferred.

This embodiment preferably contains a (meth)acrylate other than the component (A) as the component (C). As the component (C), one or more types from the group consisting of monofunctional (meth)acrylate, bifunctional (meth)acrylate, and polyfunctional (meth)acrylate can be used. By using component (C), the amount of hydrophilic functional groups in the composition can be adjusted, and the viscosity, inkjet coating properties, and moisture permeability can also be adjusted.

Here, the hydrophilic functional group refers to one in which the maximum electronegativity difference among the atoms constituting the functional group is 0.6 or more. As this hydrophilic functional group, preferably (meth)acrylyl group, ester group, aldehyde group, nitro group, hydroxyl group, ethylene oxide group, propylene oxide group, ether group, amide group, cyclic amide group, tritylene group, carbonyl group, carboxylic acid (salt) group, sulfonic acid (salt) group, sulfinic acid (salt) group, phosphonic acid (salt) group, phosphate (salt) group, sulfobetaine group , carbonyl betaine base, and phosphobetaine base.

Examples of the monofunctional (meth)acrylate as the component (C) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-Ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. Alkyl (meth)acrylate, benzyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-tetra(meth)acrylate Methyl phenyl ester, 4-chlorophenyl (meth)acrylate, phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxy-3 (meth)acrylate -Phenoxypropyl ester (2-HPA), 2-(meth)acryloxyhexahydrophthalic acid, 2-(meth)acryloxyethyl-2-hydroxypropylphthalate Formic 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, (meth)acrylic acid-2-hydroxy-3 -Phenoxypropyl ester, phenol ethylene oxide modified (meth)acrylate, phenol (ethylene oxide modified with 2 moles) (meth)acrylate, phenol (ethylene oxide modified with 4 moles) (meth)acrylate, p-cumylphenol ethylene oxide modified (meth)acrylate, nonylphenol ethylene oxide modified (meth)acrylate, nonylphenol (epoxy Ethane modified with 4 moles) (meth)acrylate, nonylphenol (ethylene oxide modified with 8 moles) (meth)acrylate, nonylphenol (propylene oxide modified with 2.5 moles) ( Meth)acrylate, ethylene oxide modified phthalate (meth)acrylate, hydroxyethyl phthalate mono(meth)acrylate, etc. have more than one aromatic hydrocarbon ring structure in the molecule (hereinafter referred to as aromatic hydrocarbon group) monofunctional (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, Dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, isocamphenyl (meth)acrylate, methoxylated cyclotrienyl (meth)acrylate, etc. Monofunctional (meth)acrylate with an aliphatic hydrocarbon-based cyclic structure (hereinafter referred to as alicyclic hydrocarbon group), (meth)acrylic acid methoxylated cyclotrienyl, (meth)acrylic acid-2-hydroxy Ethyl ester, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (meth)acrylate Meth)glycidyl acrylate, caprolactone-modified (meth)acrylic acid tetrahydrofurfuryl ester, (meth)acrylic acid-3-chloro-2-hydroxypropyl ester, (meth)acrylic acid-N,N- Dimethylaminoethyl ester, (meth)acrylic acid-N,N-diethylaminoethyl ester, (meth)acrylic acid tertiary butylaminoethyl ester, (meth)acrylic acid ethoxycarbonylmethyl ester, 2 -Ethylhexyl carbitol (meth)acrylate, ethylene oxide modified succinate (meth)acrylate, trifluoroethyl (meth)acrylate, (meth)acrylic acid, maleic acid, fumaric acid , ω-carboxy-polycaprolactone mono(meth)acrylate, (meth)acrylic acid dimer, β-(meth)acryloxyethyl hydrosuccinate, n-(meth)acrylamide Oxyalkyl hexahydrophthalimide, (meth)acrylic acid-2-(1,2-cyclohexacarboxylimide)ethyl, etc. As the monofunctional (meth)acrylate of the component (C), a (meth)acrylate having a cyclic structure containing a heterocyclic structure such as a cyclic amide group, a tetrahydrofurfuryl group, or a piperidinyl group can be used.

Examples of the bifunctional (meth)acrylate as the component (C) include dicyclopentyl di(meth)acrylate, 2-ethyl-2-butyl-propanediol (meth)acrylate, and neopentyl acrylate. Diol-modified trimethylolpropane di(meth)acrylate, stearic acid-modified neopentylerythritol 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)acryloxypropane Oxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, (meth)acrylic acid-2-(1,2-cyclohexacarboxylic acid) Amine) ethyl ester, bisphenol A epoxy di(meth)acrylate, etc. Examples of the bifunctional (meth)acrylate of component (C) include ethoxylated bisphenol A di(meth)acrylate compound represented by the following structural formula, propoxylated bisphenol A di(meth)acrylate compound represented by the following structural formula Meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, etc. R in the following formula is independently a hydrogen atom or a methyl group. Regarding m and n in the formula, m+n=2 to 10 is preferred. [Chemical 1]

Examples of the polyfunctional (meth)acrylate as the component (C) include trimethylolpropane tri(meth)acrylate and tris[(meth)acryloxyethyl]isocyanurate. , dimethylolpropane tetra(meth)acrylate, neopentylerythritol tetra(meth)acrylate, neopentylerythritol ethoxytetra(meth)acrylate, dineopenterythritol penta(meth)acrylate ) acrylate, dipenterythritol hexa(meth)acrylate, etc.

The hydrophilic functional group amount of 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 OLED device reliability can be ensured. From the viewpoint of reactivity and OLED device reliability, the hydrophilic functional group amount of component (C) is preferably 4.00 to 15.00 mmol/g, more preferably 4.10 to 8.20 mmol/g, and still more preferably 4.20 to 7.60 mmol/g.

From the viewpoint of reactivity, OLED element reliability, and inkjet coating properties, (C) component is preferably a (meth)acrylic acid alkyl ester with a carbon number of 8 or more and a (meth)acrylic acid having an alicyclic hydrocarbon group. One or more types of the group consisting of esters and (meth)acrylate esters having aromatic hydrocarbon groups. The alkyl (meth)acrylate having 8 or more carbon atoms is preferably isooctyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, or hard (meth)acrylate. One or more types of fatty esters are selected from the group consisting of lauryl (meth)acrylate. As the (meth)acrylate having an alicyclic hydrocarbon group, preferred examples include cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, A group consisting of dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, isocamphenyl (meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate More preferably, it is composed of dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentyl (meth)acrylate. One or more types of the group consisting of cyclopentenyloxyethyl ester and dicyclopentyloxyethyl (meth)acrylate. 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 100 parts by mass of the total of component (A) and component (C). If the content of (A) is 30 parts by mass or more, the inkjet coating properties, low moisture permeability, and reliability of the organic EL element will be excellent. From the viewpoint of inkjet coating properties, low moisture permeability, and organic EL element reliability, 55 to 99 parts by mass is preferred, 60 to 95 parts by mass is more preferred, and 65 to 95 parts by mass is further preferred.

If (C) is present, the content of component (C) is preferably more than 0 parts by mass and 70 parts by mass or less based on 100 parts by mass of the total of component (A) and component (C). If the content of component (C) is 70 parts by mass or less, the inkjet coating properties, low moisture permeability, and organic EL element reliability will be excellent. From the viewpoint of inkjet coating properties, low moisture permeability, and organic EL element reliability, 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 ~35 parts by mass.

As mentioned above, OLED elements are easily deteriorated by moisture, so the composition of this embodiment is preferably one that contains less water. From the viewpoint of OLED element reliability, the water content is preferably 90 ppm or less, more preferably 50 ppm or less, and still more preferably 30 ppm or less.

This moisture content can be determined using a commercially available moisture meter, typically a Carl Fisher moisture meter.

The method of reducing the water content is not particularly limited, and the following methods may be cited.

(1) Remove moisture with desiccant. After removing the water, the desiccant is separated by decantation or filtration. The desiccant is not particularly limited as long as it does not affect the resin composition. Examples include polymer adsorbents (molecular sieves, synthetic zeolites, alumina, silica gel, etc.), inorganic salts (calcium chloride, anhydrous magnesium sulfate, Quick lime, anhydrous sodium sulfate, anhydrous calcium sulfate, etc.), solid alkali (sodium hydroxide, potassium hydroxide, etc.), etc. (2) Heating and removing moisture under reduced pressure conditions. (3) Distillation and purification under reduced pressure. (4) Blow inert gas such as dry nitrogen or dry argon into each component to remove moisture. (5) Remove moisture by freeze-drying.

Reducing the moisture content can reduce the moisture content of each ingredient before mixing, or it can reduce the moisture content after mixing the ingredients. One or more types of water content reduction steps can be used. In order to prevent moisture from being mixed in again after the moisture content reduction step, it is preferably processed in an inert gas environment.

In addition, as mentioned above, OLED elements are easily degraded by oxygen, so the composition of this embodiment is preferably one with a smaller amount of dissolved oxygen. From the viewpoint of OLED element reliability, 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 by the composition to generate inert peroxide radicals, which has the effect of inhibiting the viscosity increase accompanying the polymerization of the composition. Therefore, from the perspective of storage stability From this point of view, it is preferably 1 ppm or more, and more preferably 2 ppm or more.

This amount of dissolved oxygen can be measured by a titration method using a reagent, a diaphragm electrode method using a diaphragm, a fluorescence method using a fluorescent substance, etc. The measurement method is not particularly limited, but for simplicity, the diaphragm electrode method is preferred.

The method of reducing the amount of dissolved oxygen is not particularly limited, and examples thereof include the following methods.

(1) Exposure to reduced pressure conditions and removal of oxygen. (2) Blow inert gas such as dry nitrogen or dry argon into each component and remove oxygen. (3) Exposure to low oxygen concentrations and removal of oxygen.

The amount of dissolved oxygen can be reduced by reducing oxygen to each component before mixing, or by reducing oxygen after mixing each component. One or more types of steps for reducing the amount of dissolved oxygen may be used. In order to prevent oxygen from being mixed in again after the step of reducing the amount of dissolved oxygen, it is preferably processed in an inert gas environment.

In the composition of this embodiment, (meth)acrylate is preferably a monomer from the viewpoint of inkjet ejection properties. It is preferable that (A) component or (C) component is a monomer. The molecular weight of the monomer is preferably 1,000 or less. From the viewpoint of inkjet ejection properties, in 100 parts by mass of (meth)acrylate containing component (A) or (C), the bifunctional (meth)acrylate oligomer/polymer and the polyfunctional The (meth)acrylate oligomer/polymer is preferably contained at most 3 parts by mass, more preferably at most 1 part by mass, and most preferably not contained. Oligomer/polymer refers to one or more types of a group consisting of oligomers and polymers. The molecular weight of the oligomer/polymer is preferably in excess of 1000.

In order to improve storage stability, the composition of this embodiment may use (D) antioxidant. Examples of antioxidants include methylhydroquinone, hydroquinone, octadecyl 3-[3,5-ditertiary butyl-4-hydroxyphenyl]propionate, and 2,2-methylene-bis (4-methyl-6-tertiary butylphenol), catechol, hydroquinone monomethyl ether, monotertiary butylhydroquinone, 2,5-ditertiary butylhydroquinone, p-benzoquinone , 2,5-diphenyl-p-benzoquinone, 2,5-di-tertiary butyl-p-benzoquinone, picric acid, citric acid, phenothiazine, tertiary butylcatechol, 2-butyl- 4-Hydroxyanisole and 2,6-di-tertiary butyl-p-cresol, etc. A combination of two or more antioxidants is preferred. Among these, phenol-based antioxidants are preferred because they have better effects such as transparency and storage stability. Among the phenol antioxidants, hindered phenol antioxidants are preferred. As the hindered phenol-based antioxidant, preferred are stearyl 3-[3,5-ditertiary butyl-4-hydroxyphenyl]propionate, 2,2-methylene-bis(4-methyl 1 or more species from the group consisting of 6-tertiary butylphenol), more preferably containing 3-[3,5-ditertiary butyl-4-hydroxyphenyl]octadecylpropionate and 2,2-methylene-bis(4-methyl-6-tertiary butylphenol). Examples of stearyl 3-[3,5-ditertiary butyl-4-hydroxyphenyl]propionate include "Irganox 1076" manufactured by BASF Japan Co., Ltd. and the like. Examples of 2,2-methylene-bis(4-methyl-6-tertiary butylphenol) include "SUMILIZER MDP-S" manufactured by Sumitomo Chemical Industries, Ltd., and the like. Contains 3-[3,5-di-tertiary butyl-4-hydroxyphenyl]octadecylpropionate and 2,2-methylene-bis(4-methyl-6-tertiary butylphenol) When, 3-[3,5-di-tertiary butyl-4-hydroxyphenyl]octadecylpropionate and 2,2-methylene-bis(4-methyl-6-tertiary butylphenol) ) content ratio is 3-[3,5-di-tertiary butyl-4-hydroxyphenyl]octadecylpropionate and 2,2-methylene-bis(4-methyl-6-tertiary Butylphenol), preferably the mass ratio is 3-[3,5-di-tertiary butyl-4-hydroxyphenyl]octadecylpropionate:2,2-butylphenol). Methyl-bis(4-methyl-6-tertiary butylphenol)=10~90:90~10, more preferably 25~75:75~25.

The antioxidant content is preferably 0.001 to 3 parts by mass, more preferably 0.01 to 2 parts by mass, based on 100 parts by mass of the total of component (A) and component (C). If it is 0.001 parts by mass or more, storage stability can be ensured. If it is 3 parts by mass or less, good adhesion can be obtained and there will be no unhardened state.

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 sealing compound for organic EL display elements.

Examples of a method for curing the composition by irradiating it with visible rays or ultraviolet rays include a method in which the composition is cured by irradiating at least one of visible rays or ultraviolet rays. Examples of 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 mixed lamps, halogen lamps, excimer lamps, and indium lamps. Energy irradiation sources such as thallium lamps, LED lamps, and electrodeless discharge lamps. From the viewpoint of being less likely to cause damage to organic EL elements, the composition of the present embodiment is preferably cured at a wavelength of 380 nm or more, more preferably 395 nm or more, and most preferably 395 nm. Since emitting infrared light will increase the temperature of the irradiated part and may cause damage to the organic EL element, the wavelength of the energy irradiation source is preferably 500 nm or less. As the energy irradiation source, an LED lamp with a single wavelength is preferred.

When irradiating visible light or ultraviolet rays to harden the composition, it is preferable to irradiate the composition with energy rays of 100 to 8000 mJ/cm ² at a wavelength of 395 nm to harden the composition. If it is between 100 and 8000mJ/ ^cm2 , the composition can be hardened and sufficient bonding strength can be obtained. If it is above 100mJ/ ^cm2 , the composition can be fully hardened. If it is below 8000mJ/ ^cm2 , it will not cause damage to the organic EL element. The energy required for hardening the composition is more preferably 300 to 2000 mJ/cm ² .

The transparency of the composition of this embodiment is as follows. When the organic film thickness is 1 μm or more and 10 μm or less, the spectral transmittance in the ultraviolet-visible light region from 360 nm to 800 nm 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.

If the inorganic/organic laminate is counted as one group, the sealing layer composed of the composition of this embodiment is preferably 1 to 5 groups. This is because when the inorganic/organic laminate is composed of 6 or more groups, the sealing effect on the organic EL element is almost the same as that of 5 groups. The inorganic film thickness of the inorganic/organic laminate is preferably 50 nm to 1 μm. The organic film thickness of the inorganic/organic laminate is preferably 1 to 15 μm, more preferably 3 to 10 μm. If the organic film thickness is 1 μm or more, particles generated during device formation can be completely covered, and the inorganic film can be coated while ensuring flatness. If the thickness of the organic film is 15 μm or less, moisture will not penetrate from the side of the organic film, and the reliability of the organic EL element can be improved.

The sealing substrate is closely adhered to cover the entire upper surface of the uppermost organic film of the sealing layer. Examples of the sealing substrate include the aforementioned substrates. Among these, a substrate transparent to visible light is preferred. Among the substrates that are transparent to visible light (transparent sealing substrates), it is preferable that they be at least one of the group consisting of glass substrates and plastic substrates, and more preferably they are glass substrates.

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 disposing the transparent sealing substrate on the upper layer of the sealing layer, the surface of the organic film on the uppermost layer is prevented from deteriorating due to contact with gas, thereby improving the shielding properties of the organic EL device.

Next, a method for manufacturing an organic EL device having the above structure will be described. First, an anode patterned in a predetermined shape, an organic EL layer containing a light-emitting layer, and a cathode are sequentially formed on the first substrate by using conventional methods, and an organic EL element is formed. For example, when an organic EL device is used as a dot matrix display device, banks are formed to partition light-emitting areas into a matrix shape, 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 first film having a predetermined thickness is formed by a film-forming method such as a PVD (Physical Vapor Deposition) method such as sputtering or a CVD method such as a plasma CVD (Chemical Vapor Deposition) method. Inorganic film. Thereafter, the composition of this embodiment is adhered to the first inorganic film using a coating film forming method such as a solution coating method or a spray coating method, a flash evaporation method, an inkjet method, or the like. From the viewpoint of productivity, the inkjet method is preferred among these. Thereafter, the composition is hardened by irradiating ultraviolet rays, electron beams, plasma and other energy rays to form a first organic film. Through the above steps, a set of inorganic/organic layered bodies is formed. The curing rate of the composition is not particularly limited as long as the effect of the present embodiment can be exerted. For example, the value obtained by the measurement method described below is preferably 90% or more, and more preferably 95% or more.

The steps of forming the inorganic/organic layered body shown above are repeated only a predetermined number of times. However, for the last group, that is, for the uppermost inorganic/organic laminate, the composition can be attached to the upper surface of the inorganic film by a coating method, flash evaporation method, inkjet method, etc. in such a way that the upper surface is planarized.

Next, a transparent sealing substrate is bonded to the surface on which the composition is attached. Align when fitting. Thereafter, the composition of this embodiment existing between the uppermost inorganic film and the transparent sealing substrate is cured by irradiating energy rays from the transparent sealing substrate side. Thereby, the composition is hardened, and the uppermost organic film is formed, while the uppermost organic film is bonded to the transparent sealing substrate. In the above manner, the manufacturing method of the organic EL device is completed.

After the composition is attached to the inorganic film, the composition may be partially irradiated with energy rays to polymerize it. In this way, when the transparent sealing substrate is placed, the composition of the uppermost organic film can be prevented from being broken in shape. The thickness of the inorganic film and the organic film may be the same in each inorganic/organic laminate, or may be different in each inorganic/organic laminate.

The above description is based on a top-emission organic EL device as an example. However, this embodiment can also be applied to a bottom-emission organic EL device in which light generated by the 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.

If a sealing layer is formed according to this embodiment, the sealing layer is used to isolate the organic EL element formed on the first substrate from outside air, and a transparent sealing substrate is further disposed on the sealing layer, it is possible to obtain an organic EL element having Sealed structure with sufficient barrier properties against water vapor and oxygen. According to this embodiment, a sealing structure having sufficient bonding 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, the transparent sealing substrate is placed without curing the composition, and then the composition is cured, so that the composition can be formed. At the same time as the uppermost organic film of the sealing layer is formed, the sealing layer and the transparent sealing substrate are bonded. As a result, compared with the case where the sealing layer and the transparent sealing substrate are bonded with an adhesive, this embodiment has the effect of simplifying the steps.

According to JIS Z 0208:1976, the moisture permeability value of the composition of this embodiment measured at a thickness of 100 μm when the cured body is exposed to an environment of 85° C. and 85% RH for 24 hours is preferably 350 g/m ² or less. If the moisture permeability is 350g/m2 ^or less, moisture will not reach the organic light-emitting material layer, and dark spots will not easily occur.

According to this embodiment, it can be easily applied by the inkjet method, and it is possible to provide a sealant for organic EL display elements that is excellent in the reliability of the OLED element, the transparency of the cured body, and the shielding properties. According to this embodiment, a method for manufacturing an organic EL display element using a sealant for organic EL display elements can be provided. The inkjet method is a method in which fine droplets are ejected from a nozzle and applied to an object in a non-contact manner.

(Example) (Experimental Examples 1 to 17) Compositions were prepared and evaluated by the following method.

(making composition) Use the materials listed in Table 1. After mixing each material with the composition shown in Table 2, the mixture was dehydrated using molecular sieves (5A tablet form manufactured by UNION SHOWA Co., Ltd.). After dehydration, the composition was prepared by exposing it in a glove box with an oxygen concentration of 5 ppm or less for more than 72 hours. Using the obtained composition, the E-type viscosity, water content, dissolved oxygen content, moisture permeability, coating area expansion rate, hardening rate, transparency, and organic EL evaluation were measured using the evaluation methods shown below. The results are shown in Table 2. The abbreviations shown in Table 1 are used for the composition names in Table 2.

[Table 1]

[Table 2]

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

[moisture content] The moisture content of the composition was measured using AQUAMICRON AX (manufactured by Mitsubishi Chemical Co., Ltd.) as a Karl Fisher solution and a trace moisture measuring device CA-06 (manufactured by Mitsubishi Chemical Co., Ltd.).

[dissolved oxygen content] 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 Jaffani cell type)").

[Light Curing Conditions] When evaluating the cured physical properties of the composition, the composition was cured under the following light irradiation conditions. Hardening is achieved by photohardening the composition using an LED lamp that emits a 395nm wavelength (UV-LED LIGHT SOURCE H-4MLH200-V1 manufactured by HOYA Co., Ltd.) under the condition that the cumulative light amount of the 395nm wavelength is 1,500mJ/cm ² body.

[Moisture permeability] A thin sheet-like hardened body with a thickness of 0.1 mm was produced under the above photocuring conditions. According to JIS Z0208: 1976 "Test method for moisture permeability of moisture-proof packaging materials (cup method)", calcium chloride (anhydrous) was used as a hygroscopic agent. Measured under the conditions of temperature 85°C and relative humidity 85%.

The above-mentioned composition after curing and the above-mentioned composition before curing were used to use an infrared spectrometer (Nicole is5, DTGS detector, made by Thermo Fisher Scientific Co., Ltd., resolution 4 cm ^-1 ), and infrared light was incident on the measurement sample to measure the infrared rays. Spectroscopic spectrum. In the obtained infrared spectroscopic spectrum, the stretching vibration peak of the methylene carbon-hydrogen bond observed near 2950cm ^-1 was used as an internal standard without peak change before and after hardening. From the peak area of the internal standard before and after hardening, and 810cm ^- The area before and after hardening of the peak near ¹ is calculated using the following formula. The peak near 810 cm ^-1 belongs to the out-of-plane bending vibration peak of the carbon-hydrogen bond bonded to the (meth)acrylate carbon-carbon double bond. Hardening rate (%) = [1-(Ax/Bx)/(Ao/Bo)]×100 Here, Ao: represents the peak area before hardening near 810 cm ^-1 . Ax: represents the peak area after hardening near 810cm ^-1 . Bo: Indicates the peak area before hardening near 2950cm ^-1 . Bx: Indicates the peak area after hardening near 2950cm ^-1 .

[Transparency] The compositions obtained in each experimental example were formed into a thickness of 10 μm between two 25 mm × 25 mm × 1 mmt (mm thick) glass plates (alkali-free glass, Eagle XG manufactured by Corning Corporation), and an LED lamp was used. A hardened body was obtained by irradiating ultraviolet rays with a wavelength of 395 nm at an irradiation dose of 1500 mJ/cm ² and thereby hardening. The obtained hardened body was measured for the spectral transmittance at 380 nm, 412 nm, and 800 nm with an ultraviolet-visible light spectrophotometer ("UV-2550" manufactured by Shimadzu Corporation) and used as transparency.

[Coating area expansion rate] The composition obtained in each experimental example was placed on a 70 mm × 70 mm × 0.7 mmt base material (alkali-free glass (Eagle XG manufactured by Corning Co., Ltd.)) using an inkjet discharge device (MID500B manufactured by Musashi Engineering Co., Ltd., a solvent-based head "MID head" 》) Apply the pattern so that it becomes 4mm×4mm×10μmt. The alkali-free glass is cleaned with acetone and isopropyl alcohol before use, and then cleaned with UV-208, a UV ozone cleaning device manufactured by Technology Vision Co., Ltd., for 5 minutes. After applying the pattern, leave it for 5 minutes at an ambient temperature of 23°C and a relative humidity of 50%. The flatness after inkjet coating is evaluated by the coating area expansion rate (refer to the following formula). The smaller the coating area expansion ratio, the better the evaluation is because the shape after coating is maintained and the position controllability is excellent. (Expansion rate of coating area) = ((Contact area of the composition contacting the surface of the substrate after 5 minutes of coating the pattern)/(Contact area of the composition contacting the surface of the substrate after coating the pattern)) × 100 (%)

[Organic EL evaluation]

[Production of organic EL element substrate] Use acetone and isopropyl alcohol to clean a 30mm square glass substrate with an ITO electrode (thickness 700μm). Then, the following compounds were sequentially evaporated to form a thin film using a vacuum evaporation method to obtain a 2 mm square organic EL element composed of anode/hole injection layer/hole transport layer/light-emitting layer/electron injection layer/cathode. substrate. Each layer is composed as follows. ･Anode: ITO, anode film thickness 150nm ･Hole injection layer: 4,4’,4”-tris{2-naphthyl(phenyl)amine}triphenylamine (2-TNATA) ･Hole transport layer: N,N’-diphenyl-N,N’-dinaphthylbenzidine (α-NPD) ･Light-emitting layer: Tris(8-hydroxyquinoline)aluminum (metal complex material), the film thickness of the light-emitting layer is 1000Å, and the light-emitting layer functions as an electron transport layer. ･Electron injection layer: lithium fluoride ･Cathode: Aluminum, film thickness 150nm

[Production of organic EL elements] Thereafter, a mask (cover) having an opening of 10 mm × 10 mm was installed to cover the 2 mm × 2 mm organic EL element, and a SiN film was formed by the plasma CVD method. Next, in a nitrogen atmosphere, the composition (organic film) obtained in each experimental example was applied with a thickness of 10 μm to cover a 2 mm × 2 mm organic EL element using the above-mentioned inkjet device. After curing the composition under the above-mentioned photocuring conditions, A mask (cover) having an opening of 10 mm × 10 mm was provided to cover the entire hardened body, and a SiN film was formed by a plasma CVD method to obtain an organic EL display element.

The thickness of the formed SiN (inorganic film) is approximately 1 μm. Thereafter, a 30 mm × 30 mm × 25 μmt transparent double-sided adhesive tape without a base material was bonded to a 30 mm × 30 mm × 0.7 mmt alkali-free glass (Eagle XG manufactured by Corning Corporation) to produce an organic EL element (organic EL evaluation).

[Initial stage] Apply a voltage of 6V to the produced organic EL element for 10 seconds, observe the luminous state of the organic EL element visually and under a microscope, and measure the diameter of the dark spot.

[Durability] After the prepared organic EL element was exposed to conditions of 85°C and 85 mass% relative humidity for 500 hours, a voltage of 6V was applied, the luminescent state of the organic EL element was observed visually and under a microscope, and the dark spot diameter was measured.

The diameter of the dark spot can be used as an indicator to grasp and evaluate the degree of penetration of the sealant into the pinholes of the passivation film, and the degree of outgassing of the moisture in the sealant. The evaluation of the dark spot diameter is preferably 300 μm or less, more preferably 50 μm or less, and most preferably no dark spots exist.

The following facts are known from the above experimental examples.

The composition of this embodiment can provide a composition that is excellent in the reliability of organic EL elements, ejection properties by high-precision inkjet, shape retention after inkjet coating, and low moisture permeability.

Contains alkylene glycol di(meth)acrylate with a carbon number of 4 to 20 as the component (A) and a photopolymerization initiator as the component (B), and the hydrophilicity of each (meth)acrylate When the amount of functional groups satisfies the range of 4.80 to 7.60 mmol/g, the resin will be excellent in reliability, inkjet dischargeability, flatness after coating, and low moisture permeability. In addition, the diameter of the dark spots generated in the initial stage was also small (Experimental Examples 1 to 12).

On the other hand, when the amount of hydrophilic functional groups does not fall within the range of 4.80 to 7.60 mmol/g, not only the diameter of the initial dark spots will be large, but also the moisture permeability will be high, causing reliability problems (Experimental Examples 13 to 17) .

In addition, when alkylene glycol di(meth)acrylate with a carbon number of 4 to 20 is not used, the coating area expansion rate is small, and there are not only problems with inkjet ejection properties and flatness after coating, but also with high moisture permeability. The problem of trustworthiness (experimental example 15).

[Industrial Applicability] The composition of this embodiment has excellent high-precision inkjet discharge properties and flatness after inkjet coating, and has low moisture permeability and transparency, so that the organic EL element does not deteriorate. This embodiment enables inkjet coating in a short time. The composition of this embodiment is suitable for use in electronic products, especially display parts such as organic EL, or electronic parts such as image sensors called CCD and CMOS. It can also be used for bonding of component packages used in semiconductor parts and the like. It is particularly suitable for use as an adhesive for organic EL sealing and satisfies the characteristics required for adhesives for sealing devices such as organic EL devices.

The above composition is an aspect of this embodiment, and sealants for organic EL elements, cured bodies, covering bodies, bonded bodies, organic EL devices, displays, and manufacturing methods thereof using the composition of this embodiment are also included. Have the same composition and effects.

Claims (21)

A sealant for organic electroluminescent display elements, containing (A) alkylene glycol di(meth)acrylate with a carbon number of 4 to 20 and less than 20, and (B) a photopolymerization initiator, each (meth)acrylic acid The amount of hydrophilic functional groups of the ester is in the range of 4.80 to 7.60 mmol/g. The sealing compound for organic electroluminescent display elements according to Claim 1, which further contains (C), and (C) is a (meth)acrylate other than the component (A). With respect to the component (A) and (C) For a total of 100 parts by mass of components, component (A) contains 30 parts by mass or more and less than 100 parts by mass, component (B) contains 0.05 to 6 parts by mass, and component (C) contains more than 0 parts by mass and less than 70 parts by mass. For example, the sealant for organic electroluminescent display elements of claim 2, wherein the amount of hydrophilic functional groups of each (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, wherein the viscosity measured with an E-type viscometer at 25°C is 2 mPa･s or more and 50 mPa･s or less. The sealant for organic electroluminescent display elements according to any one of claims 1 to 4, wherein the water content is 90 ppm or less. The sealant for organic electroluminescent display elements according to any one of claims 1 to 5, wherein the dissolved oxygen content is 1 ppm or more and 20 ppm or less. The sealant for organic electroluminescent display elements according to any one of claims 1 to 6, which does not contain difunctional (meth)acrylate oligomers/polymers and multifunctional (meth)acrylate oligomers. material/polymer. The sealing compound for organic electroluminescent display elements according to any one of claims 1 to 7, wherein the component (A) is an alkylene glycol di(meth)acrylate having a carbon number of 12 to 16. The sealant for organic electroluminescent display elements according to any one of claims 1 to 8, wherein the component (A) is 1,12-dodecanediol di(meth)acrylate. The sealant for organic electroluminescent display elements according to any one of claims 2 to 9, wherein the component (C) is a (meth)acrylic acid alkyl ester having 8 or more carbon atoms, (meth)acrylic acid alkyl ester having an alicyclic hydrocarbon group, group) acrylate and (meth)acrylate having an aromatic hydrocarbon group. The sealing compound for organic electroluminescent display elements according to any one of claims 2 to 10, wherein the component (C) contains lauryl (meth)acrylate. The sealant for organic electroluminescent display elements according to any one of claims 2 to 11, wherein the component (C) contains dicyclopentyl (meth)acrylate and dicyclopentyloxyethyl (meth)acrylate. ester, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentyloxyethyl (meth)acrylate. The sealant for organic electroluminescent display elements according to any one of claims 2 to 12, wherein the component (C) contains ethoxylated o-phenylphenol (meth)acrylate. The sealant for organic electroluminescent display elements according to any one of claims 1 to 13, wherein the component (B) is a acylphosphine oxide derivative. A hardened body is obtained by hardening the organic electroluminescent display element according to any one of claims 1 to 14 with a sealant. A bonded body formed by bonding the organic electroluminescent display elements according to any one of claims 1 to 14 using a sealant. A method for curing a sealant for an organic electroluminescent display element, the sealant for an organic electroluminescent display element being the sealant for an organic electroluminescent display element according to any one of claims 1 to 14, and using a wavelength of 380nm or above 500nm Hardening at the following wavelengths. A method for curing a sealant for an organic electroluminescent display element, which is the sealant for an organic electroluminescent display element according to any one of claims 1 to 14, and uses a luminescence wavelength of 395nm The LED lights are hardened. A method of coating a sealant for an organic electroluminescent display element, the sealant for an organic electroluminescent display element being the sealant for an organic electroluminescent display element according to any one of claims 1 to 14, and using an inkjet method Coating. An organic EL device including the sealant for organic electroluminescent display elements according to any one of claims 1 to 14. A display comprising the sealant for organic electroluminescent display elements according to any one of claims 1 to 14.