JP4991648B2 - Organic electroluminescent device sealant - Google Patents

Description

The present invention relates to an organic electroluminescent element sealing agent that produces a cured product that generates less outgas, has high curability, is excellent in moisture resistance, and has little coloration and high transparency.

In recent years, a photocurable resin composition has attracted attention as a sealing agent for organic electroluminescence elements.
An organic electroluminescent element (organic EL element) has a laminated structure in which an organic light emitting material layer is sandwiched between a pair of electrodes facing each other, and electrons are injected from one electrode into the organic light emitting material layer. By injecting holes from the other electrode, electrons and holes are combined in the organic light emitting material layer to emit light. As described above, since the organic EL element performs self-emission, it has better visibility than a liquid crystal display element that requires a backlight, can be reduced in thickness, and can be driven by a DC low voltage. It has advantages and is attracting attention as a next-generation display.

However, in organic electroluminescent elements, the characteristics of organic light-emitting materials and electrodes constituting the laminate are likely to deteriorate due to oxidation by moisture, etc., and when driven in the air, the light-emitting characteristics deteriorate rapidly and the lifetime is short. there were. Therefore, in a general organic EL element, a glass or metal lid with a desiccant is placed on the laminate, and the periphery is sealed with an adhesive (sealing agent) to prevent moisture from entering. A blocking structure was adopted. In this method, light emitted from the laminated body is taken out from the opposite side of the lid, that is, from the bottom side of the organic EL element, so that it is also called a bottom emission method (for example, Patent Document 1).

On the other hand, in recent years, attention has been paid to a top emission type organic EL element that takes out light emitted from a laminate from the upper surface side, instead of a conventional bottom emission type organic EL element. This method has an advantage that it has a high aperture ratio and is driven at a low voltage, which is advantageous for extending the life. In such a top emission type organic EL device, usually, the laminate is sandwiched between two moisture-proof substrates made of a transparent material such as glass, and the space between the moisture-proof substrates is filled with a sealant. (For example, patent document 2 etc.).

In such a top emission type organic EL element, a method of filling with a filler composed mainly of a curable resin composition such as a photo-curable resin composition or a thermosetting resin composition has been studied so far. It had been. However, if a laminate is to be sealed using such a curable resin composition, the laminate is directly irradiated with strong light, or the laminate is exposed to high temperatures. There was a problem that the body might deteriorate.

Japanese Patent Laid-Open No. 9-148066 JP 2001-375773 A

As a result of intensive studies, the present inventors have so far used a photo-cationic polymerizable compound, an onium borate complex, and a photo-post-curing resin composition containing a curing retarder, so that strong light is directly applied to the laminate. It was found that the laminate can be sealed without irradiating. Such a light post-curing resin composition is extremely curable and excellent in moisture proofing, and by selecting a central element of onium ions, a cured product having little coloration and high transparency can be obtained. It seemed to be extremely suitable as a sealing agent for EL elements.

However, when such a photo post-curing resin composition is used, outgas is likely to occur at the time of curing, bubbles are mixed in the cured product, the transparency is impaired, the moisture resistance is reduced, There was a problem that it might corrode. In recent years, the performance required for organic EL elements has become severe due to intense performance competition with liquid crystal elements, etc., and even more stringent performance is required for sealing agents for organic EL elements. It has become.
In view of the above situation, the present invention has an object to provide an organic electroluminescent device sealing agent that can produce a cured product with less outgassing, high curability, excellent moisture resistance, and little coloration and high transparency. And

式（１１）中、Ｂは、３価のホウ素を表し、Ｒ ^６ 〜Ｒ ^９ の少なくとも１個は、炭素数６〜３０のハロゲン置換芳香族基を表す。
以下に本発明を詳述する。 The present invention is an organic electroluminescent device sealing agent containing a cationic photopolymerizable compound and an onium borate complex , wherein the onium borate complex is added in an amount of 0.1 to 100 parts by weight of the cationic photopolymerizable compound. 10 parts by weight containing onium cation constituting the onium borate complex state, and are not a hydroxyl group, and the counter ion of the onium cation, a central element boron represented by the following general formula (11) is an anion, the onium borate complex is der Ru organic electroluminescence device encapsulant having an absorption wavelength in 300 to 400 nm.

In formula (11), B represents trivalent boron, and at least one of R ^{6 to} R ⁹ represents a halogen-substituted aromatic group having 6 to 30 carbon atoms.
The present invention is described in detail below.

As a result of intensive studies, the present inventors have found that in the conventional photocurable resin composition, the onium borate complex used as the photocationic polymerization initiator causes outgassing. The onium borate complex has a very high acid generation efficiency, and when it is used as a photocationic polymerization initiator, a photocurable resin composition having extremely excellent curability can be obtained. However, the onium ions in the onium borate complex are cleaved by irradiation with light to generate two types of radicals, and polymerization is initiated by these radicals. The generated onium ion cleavage product is outgassed. I found out that it was the cause. Therefore, as a result of further intensive studies, the present inventors have used an onium borate complex composed of an onium ion having a specific structure as a photoradical polymerization initiator, while maintaining excellent performance as a photocationic polymerization initiator, The inventors have found that outgassing caused by onium ion cleavage products can be suppressed, and have completed the present invention.

The photocurable resin composition of the present invention contains an onium borate complex.
Examples of the onium salt constituting the onium borate complex include aryldiazonium salts, diaryliodonium salts, triarylsulfonium salts, phenacylsulfonium salts, hydroxylsulfonium salts, sulfooxonium salts, and pyridinium salts.

Especially, it is preferable that the onium ion which comprises the said onium borate complex has iodine or sulfur as a central element. A photocurable resin composition containing such an onium borate complex as a photocationic polymerization initiator can provide a cured product with very little coloration and high transparency. Among them, those in which the central metal is sulfur are particularly excellent in terms of transparency.
A preferred example of the onium cation is shown in the following general formula (1) and the following general formula (2).

^Wherein, R 1 to R ⁵ represents a molecule that binds to the central element.
When an onium borate complex composed of these onium cations is irradiated with light, for example, an onium cation cleavage product represented by the following general formula (3) and the following general formula (4) is generated. It is considered that these onium cation cleavage products can cause outgassing.

In the first aspect of the photocurable resin composition of the present invention, the onium cation has a hydrogen bonding group. Here, having a hydrogen bonding group means, for example, in the case of the general formula (3), either R ² or R ³ bonded to the central element, and in the case of the general formula (4), R ⁴ means that there is a hydrogen bonding group.
By having the hydrogen bonding group, the onium cation cleavage products are bonded to each other by hydrogen bonding, so that the boiling point is increased and the volatilization is difficult to occur, and the release as outgas is suppressed.

The hydrogen bonding group is not particularly limited, and examples thereof include polar groups such as a hydroxyl group, an epoxy group, a carboxyl group, an ester group, an amino group, a nitro group, and a ketone group.
When there are a plurality of molecules bonded to the central element of the onium cation, the hydrogen bonding group may be included in at least one molecule, but is preferably included in all molecules.

Although it does not specifically limit as an onium cation which has such a hydrogen bond group, For example, what is represented by following formula (5), following formula (6), and following formula (7) is mentioned.

In the 2nd aspect of the photocurable resin composition of this invention, the said onium cation has a functional group which can react and react chemically with a photocationic polymerizable compound. Here, having a functional group that can react with the photocationically polymerizable compound and chemically bond is, for example, in the case of the general formula (3), in any of R ² and R ³ bonded to the central element, In the case of the general formula (4), it means that R ⁴ has a functional group that can react with a photocationically polymerizable compound and chemically bond.
By having a functional group that can be chemically bonded by reacting with the photocationically polymerizable compound, the onium cation cleavage product reacts with the photocationically polymerizable compound and is incorporated into the cured product, so that it is difficult to volatilize and outgas. Is suppressed from being released.

The functional group capable of chemically bonding by reacting with the photocationic polymerizable compound is not particularly limited. For example, when the photocationic polymerizable compound is an epoxy group or an oxetanyl group, an epoxy group, an oxetanyl group, a polymerization Ionic double bond, hydroxyl group, carboxyl group, amino group, isocyanate group, acid anhydride and the like.
The functional group capable of chemically bonding by reacting with the photocationically polymerizable compound may be contained in at least one molecule when there are a plurality of molecules that bind to the central element of the onium cation. It is preferable that it is contained.

Although it does not specifically limit as an onium cation which has a functional group which can react and react with the said photocationic polymerizable compound, For example, what is represented by following formula (8), (9) and (10) Etc.

The counter ion of the onium cation in the onium borate complex is not particularly limited, but an anion represented by the following general formula (11) is preferable.

In formula (11), B represents trivalent boron, and at least one of R ^{6 to} R ⁹ represents a halogen-substituted aromatic group having 6 to 30 carbon atoms.
When the counter ion of the onium cation in the onium borate complex is one having such a boron as a central element, the acid strength when used as a photocationic polymerization initiator is increased, so that the photocurable resin composition The curability of the product is improved, and a cured product having a high glass transition temperature can be obtained. As a result, since the moisture permeability (moisture permeability) of the cured product of the photocurable resin composition is lowered, the lifetime of, for example, an organic EL device produced using this photocurable resin composition can be increased, Can increase the sex.

In the general formula (11), at least one of R ^{6 to} R ⁹ is a halogen-substituted aromatic group having 6 to 30 carbon atoms. The aromatic group is not particularly limited, and examples thereof include a phenyl group, a naphthyl group, and an anthracenyl group. In addition, the halogen substituent is not particularly limited, and examples thereof include chlorine, fluorine, and the like. Among these, fluorine is preferably used. The halogen substituent may be a halogen group directly bonded to the aromatic ring of the aromatic group, or it is introduced as a part of another substituent as in the case of a halo-hydrocarbyl substituent. There may be a fluoro-hydrocarbyl substituent among them.

No particular limitation is imposed on the boron-centered anions represented by the above general formula (11), for _{example, [3,5- (CF 3) 2} C 6 H 3] 4 B -, (C 6 F 5) 4 B - _{, (C 6 H 4 -p-} CF 3) 4 B -, (C 6 H 4 -m-CF 3) 4 B -, (C 6 H 4 -p-F) 4 B -, (C 6 F 5 ) ₃ (CH ₃ ) B ⁻ , (C ₆ F ₅ ) ₃ (nC ₄ H ₉ ) B ⁻ , (C ₆ H ₄ -p-CH ₃ ) ₃ (C ₆ F ₅ ) B ⁻ , (C ^{_{6 F 5) 3 FB -,}} (C 6 H 5) 3 (C 6 F 5) B -, (CH 3) 2 (C 6 H 4 -p-CF 3) 2 B -, (C 6 F 5) _{3 (n-C 18 H 37} O) B - and the like.

The preferred boron center anion contains three or more halogen-substituted aromatic groups bonded to boron, and fluorine is most preferred as the halogen substituent. Examples of the most preferred boron center anion include, for example, [3,5- (CF ₃ ) ₂ C ₆ H ₅ ] ₄ B ⁻ , (C ₆ F ₅ ) ₄ B ⁻ , (C ₆ F ₅ ) ₃ (CH ^{_{3) B -, (C 6}} F 5) 3 (n-C 4 H 9) B -, (C 6 F 5) 3 FB - , and the like.

The boron center anion molecular weight represented by the general formula (11) is preferably 400 or more. When the molecular weight is less than 400, the molecules easily move, and when the photocurable resin composition of the present invention using the onium borate complex as a photocationic polymerization initiator is used in the production of an organic EL device, electrode corrosion is caused. It may happen.

Examples of the counter ion of the onium cation in the onium borate complex include [3,5- (CF ₃ ) ₂ C ₆ H ₃ ] ₄ Al ^{− in} addition to the boron center anion represented by the general formula (11). , (C ₆ F ₅ ) ₄ Al ⁻ , (C ₆ F ₅ ) ₂ F ₄ P ⁻ , (C ₆ F ₅ ) F ₅ Sb ⁻ , (C ₆ F ₅ ) F ₅ P ^{− and the} like; other boron centers Non-nucleophilic salts; other useful anions containing other metals or metalloids can also be used.

The preferable lower limit of the absorption wavelength of the onium borate complex is 300 nm, and the preferable upper limit is 400 nm. In the photocurable resin composition of the present invention that uses the onium borate complex as a photocationic polymerization initiator to absorb light having a wavelength of less than 300 nm, normal light using a high pressure mercury lamp, an ultrahigh pressure mercury lamp, or the like as a light source When used, curing may be insufficient. If it absorbs light having a wavelength exceeding 400 nm, coloring may occur in the course of curing.

The photocurable resin composition of the present invention contains a photocationically polymerizable compound.
The photocationically polymerizable compound is not particularly limited as long as it has at least one photocationically polymerizable functional group in the molecule. For example, at least one epoxy group or oxetanyl group in the molecule. , Compounds having a hydroxyl group, a vinyl ether group, an episulfide group, an ethyleneimine group, and the like. Among them, since it has high photocationic polymerizability and photocuring proceeds efficiently even with a small amount of light, it is a compound having at least one epoxy group in the molecule (hereinafter also referred to as an epoxy compound), or in the molecule. A compound having at least one oxetanyl group (hereinafter also referred to as an oxetanyl compound) is preferably used.
The property (molecular weight) of these photocationically polymerizable compounds is not particularly limited and may be any of a monomer, an oligomer and a polymer. Moreover, these photocationic polymerizable compounds may be used independently and 2 or more types may be used together.

The epoxy compound is not particularly limited. For example, bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; Group epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, polyfunctional epoxy resin, biphenyl type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin; hydrogenated bisphenol A Type epoxy resins and other alcohol type epoxy resins; brominated epoxy resins and other halogenated epoxy resins; rubber-modified epoxy resins, urethane-modified epoxy resins, epoxidized polybutadiene, and epoxidized styrene resins Diene - styrene block copolymer, epoxy group-containing polyester resin, epoxy group-containing polyurethane resins, epoxy group-containing acrylic resins. These epoxy compounds may be used alone or in combination of two or more.

Examples of commercially available epoxy compounds include “Epicoat” series such as “Epicoat 806”, “Epicoat 828”, “Epicoat 1001”, and “Epicoat 1002” manufactured by Japan Epoxy Resin Co., Ltd. And “Celoxide” series such as “Celoxide 2021” manufactured by Daicel Chemical Industries, Ltd.

The oxetanyl compound is not particularly limited, and examples thereof include phenoxymethyl oxetane, 3,3-bis (methoxymethyl) oxetane, 3,3-bis (phenoxymethyl) oxetane, and 3-ethyl-3- (phenoxymethyl) oxetane. , 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, di [1-ethyl (3-oxetanyl)] methyl And ether, oxetanylsilsesquioxane, phenol novolac oxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, and the like. These oxetanyl compounds may be used alone or in combination of two or more.

Examples of the photo-cationic polymerizable compound other than the epoxy compound and the oxetanyl compound include, for example, epoxides, cyclic ethers, vinyl ethers, vinylamines, unsaturated hydrocarbons, lactones and other cyclic esters, and lactams. , At least one photocationically polymerizable group such as cyclic carbonates, cyclic acetals, aldehydes, cyclic amines, cyclic sulfides, cyclosiloxanes, cyclotriphosphazenes and other photocationically polymerizable groups and monomers And a photocationically polymerizable compound. Among these, cyclic ether monomers such as epoxide monomers and vinyl organic monomers are preferably used.

In the photocurable resin composition of the present invention, the compounding ratio of the photocationically polymerizable compound and the onium borate complex is not particularly limited, but the compounding amount of the onium borate complex with respect to 100 parts by weight of the photocationic polymerizable compound is not limited. A preferred lower limit is 0.1 parts by weight and a preferred upper limit is 10 parts by weight. When the amount is less than 0.1 parts by weight, the photocationic polymerization of the photocationically polymerizable compound may not sufficiently proceed, or the photocuring of the photocurable resin composition may be too slow. The photo-curing of the photo-curable resin composition becomes too fast, and the workability may be deteriorated or a non-uniform cured product may be easily obtained.

The photocurable resin composition of the present invention preferably further contains a curing retarder. By containing an appropriate amount of the curing retarder, it functions as a reaction regulator for controlling the usable time and curing time after light irradiation, and the photocurable resin composition of the present invention is used as the postphotocurable resin composition. It can be a thing. If such a photo post-curing resin composition is used, the laminate can be sealed without directly irradiating the laminate with strong light.

The curing retarder is not particularly limited as long as it is a compound having an ether bond, and examples thereof include polyalkylene oxides such as polyethylene glycol, polypropylene glycol, and polyoxytetramethylene glycol, and crown ethers. These curing retarders may be used alone or in combination of two or more.

The terminal of the polyalkylene oxide is not particularly limited, and may be a hydroxyl group, may be etherified or esterified with another compound, or may be a functional group such as an epoxy group. Among these, a hydroxyl group, an epoxy group, and the like are preferably used because they react with the photocationically polymerizable compound. Furthermore, as the polyalkylene oxide, polyoxyalkylene-added bisphenol derivatives are also preferably used, and particularly compounds having a terminal hydroxyl group or epoxy group are more preferably used.

When polyethylene glycol or polypropylene glycol is used as the curing retarder, those having two or more polyethylene glycol structures and / or polypropylene glycol structures in the molecule are suitable.
Among the curing retarders having two or more such polyethylene glycol structures in the molecule, for example, “Lika Resin BEO-60E”, “Lika Resin EO-20” (both manufactured by Shin Nippon Science Co., Ltd.) and the like can be mentioned. It is done. Moreover, as a commercial item among the hardening retarders which have two or more polypropylene glycol structures in a molecule | numerator, "Lika Resin BPO-20E", "Lika Resin PO-20" (all are made by Shin Nippon Science Co., Ltd.) etc. are mentioned, for example. .

Examples of the crown ether include 12-crown-4,15-crown-5,18-crown-6 and the like.

When the photo-curable resin composition of the present invention is used as a photo-post-curable resin composition, the pot life is 1 minute or longer until the curing reaction proceeds after the light irradiation and the adhesion cannot be performed. Is preferred. If it is less than 1 minute, curing proceeds before the substrates and the like are bonded together, and sufficient adhesive strength may not be obtained.

The minimum with preferable content of the said retarder in the photocurable resin composition of this invention is 0.1 weight part with respect to 100 weight part of photocationic polymerization initiators, and a preferable upper limit is 20 weight part.

The photocurable resin composition of the present invention may contain a photosensitizer as necessary as long as the object of the present invention is not impaired. The photosensitizer is not particularly limited, and examples thereof include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo compounds, diazo compounds, halogen compounds, and photoreductive dyes. Specifically, for example, benzoin derivatives such as benzoin methyl ether and benzoin isopropyl ether; benzophenones such as benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, and 4,4′-bis (dimethylamino) benzophenone Derivatives; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone. These photosensitizers may be used independently and 2 or more types may be used together.
The minimum with preferable content of the said photosensitizer in the photocurable resin composition of this invention is 1 weight part with respect to 100 weight part of photocationic polymerization initiators, and a preferable upper limit is 500 weight part.

The photo-curable resin composition of the present invention is, for example, an adhesive polymer or an adhesive-imparting agent (for improving the adhesive properties) as necessary within a range not impairing the object of the present invention. Tackifiers), fillers for further improving mechanical properties and durability, viscosity modifiers for adjusting viscosity, thixotropic agents for imparting thixotropic properties (thixotropic properties), mechanics Physical property modifier, coupling agent, reinforcing agent, extender, softener (plasticizer), sagging agent, antioxidant (anti-aging agent), heat stabilizer, flame retardant, antistatic You may contain well-known various additives, such as an agent and an organic solvent.

It does not specifically limit as a method to manufacture the photocurable resin composition of this invention, For example, well-known various kneaders, such as a universal mixer, a Banbury mixer, a kneader, 2 rolls, 3 rolls, an extruder, are used independently. Use or in combination, the photocationically polymerizable compound, onium borate complex and additives blended as necessary, at normal temperature or under heating, under normal pressure, under reduced pressure, under pressure, or under an inert gas stream And a method of uniformly kneading under such conditions.

The photocurable resin composition of the present invention is preferably cured by irradiation with light containing light having a wavelength of 300 nm or more, more preferably from 300 to 400 nm.
The light source for irradiating the light is not particularly limited. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an excimer laser, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, sodium. Examples thereof include lamps, halogen lamps, xenon lamps, fluorescent lamps, sunlight, and electron beam irradiation devices. These light sources may be used independently and 2 or more types may be used together.

When using these light sources, it is preferable to remove heat rays or light having a wavelength of less than 300 nm using, for example, a light cut filter or the like. Examples of the irradiation procedure of the light source to the photocurable resin composition include simultaneous irradiation of various light sources, sequential irradiation with a time difference, combined irradiation of simultaneous irradiation and sequential irradiation, and the like. An irradiation procedure may be taken.
In curing the photocurable resin composition of the present invention, heating may be performed simultaneously with light irradiation in order to further accelerate the photocationic polymerization of the photocationically polymerizable compound and further shorten the curing time. Although it does not specifically limit as heating temperature in the case of using the said heat curing together, It is preferable that it is about 50-100 degreeC.

In the photocurable resin composition of the present invention, the total light transmittance of the cured product is preferably 80% or more. When it is less than 80%, when the photocurable resin composition of the present invention is used as an encapsulant for an organic EL device, the optical characteristics of the obtained organic EL device may be insufficient.
The total light transmittance can be measured using a spectrometer (for example, “AUTOMATIC HAZEMATER MODEL TC-III DPK” manufactured by Tokyo Denshoku).

The photocurable resin composition of the present invention preferably has a light absorption rate of 350 to 700 nm of the cured product of 80% or more. When it is less than 80%, when the photocurable resin composition of the present invention is used as an encapsulant for an organic EL device, the optical characteristics of the obtained organic EL device may be insufficient.
The absorption rate of light having a wavelength of 350 to 700 nm can be measured using a chromaticity meter (for example, “COLOR ANALYZER TC-1800M” manufactured by Tokyo Denshoku Co., Ltd.).

The photocurable resin composition of the present invention preferably has a moisture permeability of 150 g / m ² · 24 h / 100 μm or less measured under conditions of 85 ° C.-85% RH in accordance with JIS Z 0208 of the cured product. . When it exceeds 150 g / m ² · 24 h / 100 μm, when the photocurable resin composition of the present invention is used as an encapsulant for an organic EL element, the life of the obtained organic EL element may be shortened.

The use of the photocurable resin composition of the present invention is not particularly limited, and examples thereof include adhesives, sealants, single-sided tapes, double-sided tapes, sealing films, sealing agents, coating agents, lining agents, printing inks, and electronics. It can use suitably for various uses, such as material. Especially, it is preferable to use as an adhesive agent or a sealing agent. Moreover, it can use suitably for transparent or translucent structures, such as a display part, using these adhesive agents, sealing agents, single-sided tapes, double-sided tapes, sealing films and the like. Especially, it is very suitable as a sealing agent for top emission type organic EL elements.
The sealing agent using the photocurable resin composition of the present invention is also one aspect of the present invention.
An organic EL device using the photocurable resin composition or sealant of the present invention is also one aspect of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element sealing agent with little generation | occurrence | production of outgas, high curability and excellent moisture-proof property, and also having little coloring and high transparency can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(1) Preparation of onium borate complex (hydrogen bonding group)
According to the methods described in JP-A-5-004996 and JP-A-9-50091, 2 parts by weight of 4-ethoxyalcohol arylsulfonium bromide is dissolved in 200 parts by weight of distilled water, and at a temperature of 25 ° C. While stirring, 50 parts by weight of an aqueous solution containing 5 parts by weight of sodium tetrakis (pentafluorophenyl) borate was added dropwise over 10 minutes. After leaving at 10 ° C. overnight, the precipitated white crystals were filtered, washed with washing water, and dried under reduced pressure to obtain 4.2 parts by weight of 4-ethoxy alcohol arylsulfonium tetrakis (pentafluorophenyl) borate. It was.

(2) Preparation of photocurable resin composition The obtained 4-ethoxy alcohol arylsulfonium tetrakis (pentafluoro) with respect to 100 parts by weight of bisphenol F type epoxy resin (trade name “Epicoat 806”, manufactured by Japan Epoxy Resin Co., Ltd.) 4 parts by weight of phenyl) borate and 3 parts by weight of polyethylene glycol (trade name “PEG # 200”, manufactured by Nippon Oil & Fats Co., Ltd.) as a curing retarder were added, stirred and kneaded uniformly, defoamed, and photocurable resin A composition was prepared.

(Reference Example 1)
(1) Preparation of onium borate complex 2 parts by weight of arylsulfonium-4-glycidyl ether bromide was added to 200 parts by weight of distilled water according to the methods described in JP-A-5-004996 and JP-A-9-500921. While being dissolved and stirred at a temperature of 25 ° C., 50 parts by weight of an aqueous solution containing 5 parts by weight of sodium tetrakis (pentafluorophenyl) borate was added dropwise over 10 minutes. After leaving overnight at 10 ° C., the precipitated white crystals were filtered, washed with washing water, dried under reduced pressure, and 4.2 parts by weight of arylsulfonium-4-glycidyl ether tetrakis (pentafluorophenyl) borate was added. Obtained.

(2) Preparation of photocurable resin composition The obtained arylsulfonium-4-glycidyl ether tetrakis (penta) with respect to 100 parts by weight of bisphenol F type epoxy resin (trade name “Epicoat 806”, manufactured by Japan Epoxy Resin Co., Ltd.) 4 parts by weight of fluorophenyl) borate and 3 parts by weight of polyethylene glycol (trade name “PEG # 200”, manufactured by Nippon Oil & Fats Co., Ltd.) as a curing retarder are added, stirred and kneaded uniformly, defoamed, and photocured. A resin composition was produced.

(Comparative Example 1)
(1) Preparation of onium borate complex An aqueous solution containing 5 parts by weight of sodium tetrakis (pentafluorophenyl) borate while dissolving 2 parts by weight of arylsulfonium bromide in 200 parts by weight of distilled water and stirring at a temperature of 25 ° C. 50 parts by weight were added dropwise over 10 minutes. After leaving overnight at 10 ° C., the precipitated white crystals were filtered, washed with washing water, and dried under reduced pressure to obtain 4.2 parts by weight of arylsulfonium tetrakis (pentafluorophenyl) borate.

(2) Preparation of photocurable resin composition The obtained arylsulfonium tetrakis (pentafluorophenyl) borate 4 with respect to 100 parts by weight of bisphenol F type epoxy resin (trade name “Epicoat 806”, manufactured by Japan Epoxy Resin Co., Ltd.) Add 3 parts by weight of polyethylene glycol (trade name “PEG # 200”, manufactured by NOF Corporation) as a curing retarder, stir and knead uniformly, and then defoam to produce a photocurable resin composition. did.

(Evaluation)
The photocurable resin compositions obtained in Example 1, Reference Example 1 and Comparative Example 1 were evaluated by the following methods.
The results are shown in Table 1.

(1) Evaluation of outgas generation amount The photocurable resin composition was applied using a bar coater so that the thickness after coating was 100 μm, and an ultrahigh pressure mercury lamp (strength at 365 nm was 40 mW) was used. After irradiation with a dose of 2000 mJ, the film was formed by heating at 80 ° C. for 30 minutes.
Using a thermal analyzer (TG / DTA6200, manufactured by Seiko Instrument Co., Ltd.), the weight loss rate when the film was heated to 150 ° C. at a temperature rising rate of 10 ° C./min was measured. did.

(2) Evaluation of lifetime of organic EL element An organic EL element was produced by the following method using the obtained photocurable resin composition.
A transparent support substrate was obtained by forming an ITO electrode with a thickness of 100 nm on a glass substrate having a size of 25 mm × 25 mm × 0.7 mm. The transparent support substrate was ultrasonically cleaned for 15 minutes with acetone, 15 minutes with an alkaline aqueous solution, 15 minutes with ion-exchanged water, 15 minutes with isopropyl alcohol, and 10 minutes with boiled isopropyl alcohol. Pretreatment was performed with an ozone cleaner (NL-UV253, manufactured by Nippon Laser Electronics Co., Ltd.).

Next, the cleaned transparent support substrate is fixed and installed in a substrate folder of a vacuum deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.) in a vacuum chamber, and N ′, N-di (1-naphthyl) -N is placed in an unglazed crucible. , N′-diphenylbenzidine (α-NPD) was put in 200 mg, and 200 mg of tris (8-hydroxyquinola) aluminum (Alq3) was put in different unglazed crucibles, and the pressure was reduced to 1 × 10 ⁻⁴ Pa.
Next, the boat containing α-NPD was heated to deposit α-NPD on a transparent support substrate at room temperature at an evaporation rate of 15 Å / s, thereby forming a 600 正 孔 thick hole transport layer. Subsequently, the port containing Alq3 was heated, and α-NPD was deposited on the hole transport layer of the transparent support substrate at a deposition rate of 15 Å / s to form an organic thin film (light emitting layer) having a thickness of 600 Å.

The transparent support substrate on which the hole transport layer and the light emitting layer were formed was once taken out from the vacuum chamber, 200 mg of lithium fluoride was put in a tungsten resistance heating boat, and 1.0 g of aluminum wire was wound around the tungsten filament. The transparent support substrate on which the hole transport layer and the light emitting layer were formed was placed in the vacuum chamber again, and the pressure was reduced to 2 × 10 ⁻⁴ Pa. The boat containing lithium fluoride was heated to deposit lithium fluoride on the light-emitting layer of the transparent support substrate at a deposition rate of 0.2 Å / s to form an electron injection layer having a thickness of 5 Å. Subsequently, the boat containing aluminum was heated, and aluminum was deposited on the electron injection layer of the transparent support substrate at a deposition rate of 20 ｓ / s to form a cathode having a thickness of 1000 、 to obtain a thin film structure.

The photocurable resin composition was coated on a glass substrate so that the thickness after coating was 70 μm, and light was irradiated for 50 seconds using an ultrahigh pressure mercury lamp (intensity at 365 nm was 40 mW). Immediately after the light irradiation, the glass substrate and the thin film structure were bonded together, and sealed by heating at 80 ° C. for 30 minutes.

The ratio of the dark spot generated when the obtained organic EL element was energized for 500 hours under the conditions of 85 ° C. and 85 RH% to the surface area of the organic EL element was measured.

ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element sealing agent with little generation | occurrence | production of outgas, high curability and excellent moisture-proof property, and also having little coloring and high transparency can be provided.

Claims (4)

An organic electroluminescent device sealing agent containing a photocationically polymerizable compound and an onium borate complex,
Containing 0.1 to 10 parts by weight of the onium borate complex with respect to 100 parts by weight of the cationic photopolymerizable compound;
Onium cation constituting the onium borate complex state, and are not a hydroxyl group, and the counter ion of the onium cation, an anion of a central element boron represented by the following general formula (11),
The onium borate complexes, organic electroluminescent element encapsulation agent characterized der Rukoto having an absorption wavelength in 300 to 400 nm.

In formula (11), B represents trivalent boron, and at least one of R ^{6 to} R ⁹ represents a halogen-substituted aromatic group having 6 to 30 carbon atoms. 2. The organic electroluminescent device sealing agent according to claim 1, wherein the onium ion constituting the onium borate complex has iodine or sulfur as a central element. The organic electroluminescent element sealing agent according to claim 1, further comprising a curing retarder. An organic electroluminescence device, which is sealed with the organic electroluminescence device sealing agent according to claim 1, 2 or 3.