JP2022027781A - Sealing agent for organic el display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing agent for an organic EL display element capable of being easily applied by an inkjet method, excellent in low outgassing property, and capable of obtaining an organic EL display element excellent in reliability.

SOLUTION: The sealing agent for an organic EL display element includes a polymerizable compound and a polymerization initiator. Viscosity at 25°C is 5 to 50 mPa s. Surface tension at 25°C is 15 to 35 mN/m. Volatility after 4 days at 25°C is 1% or less.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a sealing agent for an organic EL display element, which can be easily applied by an inkjet method and can obtain an organic EL display element having excellent low outgassing properties and excellent reliability.

The organic electroluminescence (hereinafter, also referred to as “organic EL”) display element has a laminated structure in which an organic light emitting material layer is sandwiched between a pair of electrodes facing each other, and the organic light emitting material layer is connected to the organic light emitting material layer from one electrode. When electrons are injected and holes are injected from the other electrode, the electrons and holes are combined and emit light in the organic light emitting material layer. Since the organic EL display element emits light by itself in this way, it has better visibility than a liquid crystal display element or the like that requires a backlight, can be made thinner, and can be driven by a low DC voltage. It has the advantage of.

The organic light emitting material layer and electrodes constituting the organic EL display element have a problem that their characteristics are easily deteriorated by moisture, oxygen, and the like. Therefore, in order to obtain a practical organic EL display element, it is necessary to shield the organic light emitting material layer and the electrode from the atmosphere to extend the life. Patent Document 1 discloses a method of sealing an organic light emitting material layer of an organic EL display element and an electrode with a laminated film of a silicon nitride film and a resin film formed by a CVD method. Here, the resin film has a role of preventing pressure on the organic layer and electrodes due to the internal stress of the silicon nitride film.

In the method of sealing with the silicon nitride film disclosed in Patent Document 1, organic light emission occurs when the silicon nitride film is formed due to irregularities on the surface of the organic EL display element, adhesion of foreign matter, cracks due to internal stress, and the like. It may not be possible to completely cover the material layer or electrodes. If the coating with the silicon nitride film is incomplete, moisture will infiltrate into the organic light emitting material layer through the silicon nitride film.
As a method for preventing the infiltration of water into the organic light emitting material layer, Patent Document 2 discloses a method of alternately depositing an inorganic material film and a resin film, and Patent Documents 3 and 4 Discloses a method of forming a resin film on an inorganic material film.

As a method of forming a resin film, there is a method of applying a sealant on a substrate by using an inkjet method and then curing the sealant. By using such a coating method by an inkjet method, a resin film can be formed at high speed and uniformly. However, when the sealing agent has a low viscosity in order to make it suitable for coating by the inkjet method, outgas is generated or the ink jet device cannot stably eject the sealant, resulting in insufficient sealing. There is a problem that the organic EL display element obtained is inferior in reliability.

Japanese Unexamined Patent Publication No. 2000-223264 Special Table 2005-522891 Japanese Unexamined Patent Publication No. 2001-307873 Japanese Unexamined Patent Publication No. 2008-149710

It is an object of the present invention to provide a sealing agent for an organic EL display element which can be easily applied by an inkjet method, has excellent low outgassing properties, and can obtain an organic EL display element having excellent reliability. And.

The present invention 1 contains a polymerizable compound and a polymerization initiator, has a viscosity at 25 ° C. of 5 to 50 mPa · s, a surface tension at 25 ° C. of 15 to 35 mN / m, and after 4 days at 25 ° C. A sealant for an organic EL display element having a volatilization rate of 1% or less.
Further, the present invention 2 is a sealing agent for an organic EL display element used for coating by an inkjet method, which contains a polymerizable compound and a polymerization initiator, and has a volatilization rate of 1% or less after 4 days at 25 ° C. It is a sealant for an organic EL display element.
The present invention will be described in detail below. The matters common to the sealant for the organic EL display element of the present invention 1 and the sealant for the organic EL display element of the present invention 2 are described as "the sealant for the organic EL display element of the present invention". do.

The present inventors have further studied to make the volatilization rate at 25 ° C. within a specific range for a sealing agent for an organic EL display element having excellent inkjet coatability. As a result, they have found that it is possible to obtain a sealing agent for an organic EL display element, which can be easily applied by an inkjet method, has excellent low outgassing properties, and can obtain an organic EL display element having excellent reliability. , The present invention has been completed.

The sealant for an organic EL display element of the present invention can be used as an inkjet method for coating by a non-heated inkjet method or can be used for coating by a heated inkjet method.
In the present specification, the above-mentioned "non-heated inkjet method" is a method of inkjet coating at a coating head temperature of less than 28 ° C., and the above-mentioned "heated inkjet method" is an inkjet coating at a coating head temperature of 28 ° C. or higher. It is a method of applying.

In the heating type inkjet method, an inkjet coating head equipped with a heating mechanism is used. Since the inkjet coating head is equipped with a heating mechanism, it is possible to reduce the viscosity and surface tension when discharging the sealant for the organic EL display element.

Examples of the inkjet coating head equipped with the heating mechanism include the KM1024 series manufactured by Konica Minolta and the SG1024 series manufactured by Fujifilm Dimatics.

When the sealing agent for an organic EL display element of the present invention is used for coating by the heating type inkjet method, the heating temperature of the coating head is preferably in the range of 28 ° C to 80 ° C. When the heating temperature of the coating head is in this range, the viscosity increase of the sealing agent for the organic EL display element with time is suppressed, and the ejection stability is improved.

The sealant for an organic EL display element of the present invention 1 has a lower limit of viscosity of 5 mPa · s and an upper limit of 50 mPa · s. When the viscosity is in this range, it can be suitably applied by the inkjet method.
In the present specification, the viscosity means a value measured under the conditions of 25 ° C. and 100 rpm using an E-type viscometer.

When applied by the non-heating inkjet method, the preferable lower limit of the viscosity of the sealant for an organic EL display element of the present invention is 5 mPa · s, and the preferable upper limit is 20 mPa · s. When the viscosity is in this range, it can be suitably applied by the non-heated inkjet method. A more preferable lower limit of the viscosity of the sealant for an organic EL display element of the present invention when applied by the non-heating inkjet method is 8 mPa · s, a more preferable upper limit is 16 mPa · s, a further preferable lower limit is 10 mPa · s, and further. The preferred upper limit is 13 mPa · s.

On the other hand, the preferable lower limit of the viscosity of the sealing agent for an organic EL display element of the present invention when used for coating by the heating type inkjet method is 10 mPa · s, and the preferable upper limit is 50 mPa · s. When the viscosity is in this range, it can be suitably applied by the heated inkjet method. A more preferable lower limit of the viscosity of the sealing agent for an organic EL display element of the present invention when used for coating by the heating type inkjet method is 20 mPa · s, and a more preferable upper limit is 40 mPa · s.

The sealant for an organic EL display element of the present invention 1 has a lower limit of surface tension of 15 mN / m and an upper limit of 35 mN / m. When the surface tension is in this range, it can be suitably applied by the inkjet method. The preferable lower limit of the surface tension is 20 mN / m, the preferable upper limit is 30 mN / m, the more preferable lower limit is 22 mN / m, and the more preferable upper limit is 28 mN / m.
Further, in the sealing agent for an organic EL display element of the present invention 2, the preferable lower limit of the surface tension is 15 mN / m, and the preferable upper limit is 35 mN / m. When the surface tension is in this range, it can be suitably applied by the inkjet method. A more preferable lower limit of the surface tension is 20 mN / m, a more preferable upper limit is 30 mN / m, a further preferable lower limit is 22 mN / m, and a further preferable upper limit is 28 mN / m.
The surface tension means a value measured by the Wilhelmy method with a dynamic wettability tester at 25 ° C.

The sealant for an organic EL display element of the present invention has an upper limit of the volatilization rate after 4 days at 25 ° C. of 1%. When the volatilization rate after 4 days at 25 ° C. is 1% or less, the obtained sealing agent for an organic EL display element has excellent low outgassing properties, and the obtained organic EL display element has excellent reliability. It becomes a thing. The preferable upper limit of the volatilization rate after 4 days at 25 ° C. is 0.5%, and the more preferable upper limit is 0.1%.
The volatilization rate at 25 ° C. is most preferably 0%.
The volatilization rate after 4 days at 25 ° C. was measured by putting about 10 g of a sealing agent for an organic EL display element in a plastic brown container having a diameter of 33 mm and a capacity of 50 mL, and measuring the weight (A). The weight (B) of the container after being left as it is for 4 days without a lid under a yellow lamp environment of 1 atm and 50% RH can be measured and calculated by the following formula.
Volatilization rate at 25 ° C = ((A)-(B) / (A)) × 100

The viscosity, the surface tension, and the volatility after 4 days at 25 ° C. are the selection and inclusion of these types with respect to the polymerizable compound, the polymerization initiator, and other components which may be contained, which will be described later. By adjusting the ratio, the above range can be obtained.
In particular, the volatilization rate after 4 days at 25 ° C. shall be within the above range by a method such as adjusting the boiling point or molecular weight of the polymerizable compound described later or using a hydrogen bonding component as the polymerizable compound. Can be done.
Examples of the hydrogen-binding component include -OH group, -NH ₂ group, -NHR group (R represents an aromatic group, an aliphatic hydrocarbon, or a derivative thereof), -COOH group, and -CONH ₂ group. , -Polymerable compounds having a functional group such as an NHOH group and the like can be mentioned. Further, as the hydrogen-binding component, for example, polymerization having residues such as -RO- bond, -NHCO- bond, -NH- bond, -CONHCO- bond, and -NH-NH- bond in the molecule. Sex compounds and the like can also be mentioned. Of these, a polymerizable compound having at least one of an —OH group and a —RO— bond is preferable.

The encapsulant for an organic EL display element of the present invention contains a polymerizable compound.
From the viewpoint of the volatile rate, the polymerizable compound preferably contains 95 parts by weight or more of the compound having a boiling point of 160 ° C. or higher in 100 parts by weight of the entire polymerizable compound.
The compound having a boiling point of 160 ° C. or higher preferably has a boiling point of 170 ° C. or higher, more preferably 180 ° C. or higher.
Further, the polymerizable compound more preferably contains 98 parts by weight or more of the compound having a boiling point of 160 ° C. or higher in 100 parts by weight of the entire polymerizable compound, and comprises only the compound having a boiling point of 160 ° C. or higher. Is most preferable.
In the present specification, the boiling point means a value measured under the condition of 101 kPa using a method based on JIS K 2233, or a value converted to 101 kPa in a boiling point conversion chart or the like.

The preferred lower limit of the molecular weight of the polymerizable compound is 100, and the preferred upper limit is 430. When the molecular weight of the polymerizable compound is in this range, the obtained sealing agent for an organic EL display element is more excellent in the effect of achieving both the coatability by the inkjet method and the reliability of the obtained organic EL display element. Become. The more preferable lower limit of the molecular weight of the polymerizable compound is 120, and the more preferable upper limit is 400.
In the present specification, the above-mentioned "molecular weight" is the molecular weight obtained from the structural formula for a compound whose molecular structure is specified, but for a compound having a wide distribution of degree of polymerization or a compound having an unspecified modification site, the above-mentioned "molecular weight" is used. It may be expressed using the weight average molecular weight. In the present specification, the above-mentioned "weight average molecular weight" is a value obtained by measuring by gel permeation chromatography (GPC) and converting into polystyrene. Examples of the column used when measuring the weight average molecular weight in terms of polystyrene by GPC include Shodex LF-804 (manufactured by Showa Denko KK) and the like.

As the polymerizable compound, a cationically polymerizable compound or a radically polymerizable compound can be used. Of these, cationically polymerizable compounds are preferable.

Examples of the cationically polymerizable compound include epoxy compounds, oxetane compounds, vinyl ether compounds and the like.

Examples of the epoxy compound include bisphenol A type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol O type epoxy resin, and 2,2'-diallyl bisphenol A type epoxy resin. Alicyclic epoxy resin, hydrogenated bisphenol type epoxy resin, propylene oxide added bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene Type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, dicyclopentadiene novolac type epoxy resin, biphenyl novolac type epoxy resin, naphthalenephenol novolac type epoxy resin, glycidylamine type epoxy resin, alkyl polyol type epoxy resin, Examples thereof include rubber-modified epoxy resins, glycidyl ester compounds, and epoxy-modified organopolysiloxanes. Of these, an alicyclic epoxy resin is preferable.
Among the above-mentioned alicyclic epoxy resins, commercially available ones include, for example, celoxide 2000, celoxide 2021P, celoxside 2081, celoxside 3000, celoxside 8000 (all manufactured by Daicel), and Sunsocizer EPS (manufactured by Shin Nihon Rika Kogyo Co., Ltd.). ) Etc. can be mentioned.

Examples of the oxetane compound include allyloxyoxetane, phenoxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, and 3-ethyl-3-((2-ethylhexyloxy). ) Methyl) oxetane, 3-ethyl-3-((3- (triethoxysilyl) propoxy) methyl) oxetane, 3-ethyl-3-(((3-ethyloxetane-3-yl) methoxy) methyl) oxetane, Examples thereof include oxetanyl silsesquioxane, phenol novolac oxetane, 1,4-bis (((3-ethyl-3-oxetanyl) methoxy) methyl) benzene and the like.

Examples of the vinyl ether compound include benzyl vinyl ether, cyclohexanedimethanol monovinyl ether, dicyclopentadienvinyl ether, 1,4-butanediol divinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, and dipropylene glycol. Examples thereof include divinyl ether and tripropylene glycol divinyl ether.

As the radically polymerizable compound, a (meth) acrylic compound is preferable.
The (meth) acrylic compound may be a monofunctional (meth) acrylic compound or a polyfunctional (meth) acrylic compound, and the monofunctional (meth) acrylic compound and the polyfunctional (meth) compound may be used. It may be used in combination with an acrylic compound.
In the present specification, the above-mentioned "(meth) acrylic" means acrylic or methacrylic, and the above-mentioned "(meth) acrylic compound" means a compound having a (meth) acryloyl group, and the above-mentioned "(meth)". "Acryloyl" means acryloyl or methacryloyl.

The monofunctional (meth) acrylic compound preferably has a cationically polymerizable group from the viewpoint of low outgassing property and the like.
Examples of the cationically polymerizable group include a vinyl ether group, an epoxy group, an oxetanyl group, an allyl ether group, a vinyl group, a hydroxyl group and the like.

Specific examples of the monofunctional (meth) acrylic compound include 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, and (meth) acrylic. 2- (2-Vinyloxyethoxy) ethyl acid, 3-ethyl-3- (meth) acrylic oxymethyloxetane, allyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol Examples thereof include (meth) acrylate, ethoxytriethylene glycol (meth) acrylate, and 2- (2-vinyloxyethoxy) ethyl (meth) acrylate. Of these, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, and 2- (2-vinyloxyethoxy) ethyl (meth) acrylate are preferable.
In the present specification, the above-mentioned "(meth) acrylate" means acrylate or methacrylate.

When the polymerizable compound contains the monofunctional (meth) acrylic compound, the preferable lower limit of the content of the monofunctional (meth) acrylic compound in 100 parts by weight of the polymerizable compound is 20 parts by weight, and the preferable upper limit is 80 parts by weight. It is a weight part. When the content of the monofunctional (meth) acrylic compound is in this range, the obtained sealing agent for an organic EL display element is excellent in low outgassing property and the like. The more preferable lower limit of the content of the monofunctional (meth) acrylic compound is 30 parts by weight, and the more preferable upper limit is 60 parts by weight.

The polyfunctional (meth) acrylic compound preferably has a polyoxyalkylene skeleton in the main chain from the viewpoint of inkjet coating property and the like.
The polyoxyalkylene skeleton preferably has 2 to 6 consecutive oxyalkylene units.
Examples of the oxyalkylene unit constituting the polyoxyalkylene skeleton include an oxyethylene unit and an oxypropylene unit.

From the viewpoint of inkjet coating property, the polyfunctional (meth) acrylic compound preferably has a structure with few carbon chain branches, and more preferably linear.

Specific examples of the polyfunctional (meth) acrylic compound include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and dipropylene glycol di (meth) acrylate. , Tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate and the like. Of these, tetraethylene glycol di (meth) acrylate is preferable.

When the polymerizable compound contains the polyfunctional (meth) acrylic compound, the preferable lower limit of the content of the polyfunctional (meth) acrylic compound in 100 parts by weight of the polymerizable compound is 20 parts by weight, and the preferable upper limit is 80 parts by weight. It is a weight part. When the content of the polyfunctional (meth) acrylic compound is in this range, the obtained sealing agent for an organic EL display element becomes excellent in inkjet coatability and the like. The more preferable lower limit of the content of the polyfunctional (meth) acrylic compound is 30 parts by weight, and the more preferable upper limit is 60 parts by weight.

When the monofunctional (meth) acrylic compound and the polyfunctional (meth) acrylic compound are used in combination, the content ratio of the monofunctional (meth) acrylic compound and the polyfunctional (meth) acrylic compound is a weight ratio. , Monofunctional (meth) acrylic compound: Polyfunctional (meth) acrylic compound = 7: 3 to 3: 7. By setting the content ratio of the monofunctional (meth) acrylic compound and the polyfunctional (meth) acrylic compound in this range, the obtained encapsulant for an organic EL display element is made excellent in inkjet coatability and the like. be able to. The content ratio of the monofunctional (meth) acrylic compound to the polyfunctional (meth) acrylic compound is a weight ratio, and the monofunctional (meth) acrylic compound: the polyfunctional (meth) acrylic compound = 6: 4 to 4: 6. Is more preferable.

The encapsulant for an organic EL display element of the present invention contains a polymerization initiator.
As the polymerization initiator, a photocationic polymerization initiator, a thermal cationic polymerization initiator, a photoradical polymerization initiator, or a thermal radical polymerization initiator is preferably used depending on the type of the polymerizable compound used.

The photocationic polymerization initiator is not particularly limited as long as it generates protonic acid or Lewis acid by light irradiation, and may be an ionic photoacid generation type or a nonionic photoacid generation type. May be.

Examples of the anion portion of the above-mentioned ionic photoacid-generating photocationic polymerization initiator include BF _4- , PF _6- ^, SbF _6- ^, or (BX ₄ ^- ) ^- (However, X is at least two or more. (Representing a phenyl group substituted with a fluorine or trifluoromethyl group) and the like.
Examples of the ionic photoacid generation type photocationic polymerization initiator include aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, and aromatic ammonium salts, which have the anion moiety. Examples thereof include pentadiene-1-yl) ((1-methylethyl) benzene) -Fe salt and the like.

Examples of the aromatic sulfonium salt include bis (4- (diphenylsulfonio) phenyl) sulfide bishexafluorophosphate, bis (4- (diphenylsulfonio) phenyl) sulfide bishexafluoroantimonate, and bis (4-( Diphenylsulfonio) phenyl) sulfide bistetrafluoroborate, bis (4- (diphenylsulfonio) phenyl) sulfide tetrakis (pentafluorophenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- ( Phenylthio) phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenylthio) phenylsulfonium tetrafluoroborate, diphenyl-4- (phenylthio) phenylsulfonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexa Fluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonate) phenyl) sulfide bishexafluorophosphate, Bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl) Sulfide bishexafluoroantimonate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl ) Sulfide bistetrafluoroborate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl) sulfide tetrakis (pentafluorophenyl) borate, tris (4- (4-acetylphenyl) thiophenyl) Examples thereof include sulfonium tetrakis (pentafluorophenyl) borate.

Examples of the aromatic iodonium salt include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, bis (dodecylphenyl) iodonium hexafluorophosphate, and bis. (Dodecylphenyl) Iodineium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexa Fluorophosphate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrafluoroborate, 4-methylphenyl-4-( 1-Methylethyl) phenyliodonium tetrakis (pentafluorophenyl) borate and the like can be mentioned.

Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis (pentafluorophenyl) borate.

Examples of the aromatic ammonium salt include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate and 1-benzyl. -2-Cyanopyridinium tetrakis (pentafluorophenyl) boronate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, 1- (naphthylmethyl) Examples thereof include -2-cyanopyridinium tetrafluoroborate and 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) volate.

Examples of the (2,4-cyclopentadiene-1-yl) ((1-methylethyl) benzene) -Fe salt include (2,4-cyclopentadiene-1-yl) ((1-methylethyl) benzene. ) -Fe (II) hexafluorophosphate, (2,4-cyclopentadiene-1-yl) ((1-methylethyl) benzene) -Fe (II) hexafluoroantimonate, (2,4-cyclopentadiene-1) -Il) ((1-methylethyl) benzene) -Fe (II) tetrafluoroborate, (2,4-cyclopentadiene-1-yl) ((1-methylethyl) benzene) -Fe (II) tetrakis (penta) Fluorophenyl) Borate and the like can be mentioned.

Examples of the nonionic photoacid generation type photocationic polymerization initiator include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimide sulfonate and the like.

Commercially available photocationic polymerization initiators include, for example, DTS-200 (manufactured by Midori Chemical Co., Ltd.), UVI6990, UVI6974 (all manufactured by Union Carbide), SP-150, and SP-170 (all manufactured by Union Carbide). Examples thereof include ADEKA), FC-508, FC-512 (all manufactured by 3M), IRGACURE261, IRGACURE290 (all manufactured by BASF), PI2074 (all manufactured by Rhodia) and the like.

In the above thermal cationic polymerization initiator, the anion moiety is replaced with BF _4- , PF _6- ^, SbF _6- ^, or (BX ₄ ^- ) ^- (where X is substituted with at least two or more fluorine or trifluoromethyl groups. Examples thereof include a sulfonium salt, a phosphonium salt, an ammonium salt, etc., which are composed of (representing a phenyl group). Of these, sulfonium salts and ammonium salts are preferable.

Examples of the sulfonium salt include triphenylsulfonium tetrafluoroborate and triphenylsulfonium hexafluoroantimonate.

Examples of the phosphonium salt include ethyltriphenylphosphonium hexafluoroantimonate and tetrabutylphosphonium hexafluoroantimonate.

Examples of the ammonium salt include dimethylphenyl (4-methoxybenzyl) ammonium hexafluorophosphate, dimethylphenyl (4-methoxybenzyl) ammonium hexafluoroantimonate, and dimethylphenyl (4-methoxybenzyl) ammonium tetrakis (pentafluorophenyl). Borate, dimethylphenyl (4-methylbenzyl) ammonium hexafluorophosphate, dimethylphenyl (4-methylbenzyl) ammonium hexafluoroantimonate, dimethylphenyl (4-methylbenzyl) ammonium hexafluorotetrakis (pentafluorophenyl) borate, methylphenyl Dibenzylammonium hexafluorophosphate, methylphenyldibenzylammonium hexafluoroantimonate, methylphenyldibenzylammonium tetrakis (pentafluorophenyl) borate, phenyltribenzylammonium tetrakis (pentafluorophenyl) borate, dimethylphenyl (3,4-dimethyl) Benzyl) ammonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl-N-benzylanilinium hexafluoroantimonate, N, N-diethyl-N-benzylanilinium tetrafluoroborate, N, N-dimethyl-N- Benzylpyridinium hexafluoroantimonate, N, N-diethyl-N-benzylpyridinium trifluoromethanesulfonic acid and the like can be mentioned.

Commercially available thermal cationic polymerization initiators include, for example, Sun Aid SI-60, Sun Aid SI-80, Sun Aid SI-B3, Sun Aid SI-B3A, and Sun Aid SI-B4 (all of which are Sanshin Chemical Industry Co., Ltd.). , CXC1612, CXC1821 (all manufactured by King Industries) and the like.

Examples of the photoradical polymerization initiator include benzophenone-based compounds, acetophenone-based compounds, acylphosphine oxide-based compounds, titanosen-based compounds, oxime ester-based compounds, benzoin ether-based compounds, benzyls, and thioxanthone-based compounds.

Commercially available photoradical polymerization initiators include, for example, IRGACURE184, IRGACURE369, IRGACURE379, IRGACURE651, IRGACURE819, IRGACURE907, IRGACURE2959, IRGACURE OXE01, and benzoin TPO (all manufactured by BASF). Examples thereof include ethyl ether and benzoin isopropyl ether (both manufactured by Tokyo Kasei Kogyo Co., Ltd.).

Examples of the thermal radical polymerization initiator include those made of an azo compound, an organic peroxide and the like.
Examples of the azo compound include 2,2'-azobis (2,4-dimethylvaleronitrile), azobisisobutyronitrile and the like.
Examples of the organic peroxide include benzoyl peroxide, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxyester, diacyl peroxide, peroxydicarbonate and the like.

Commercially available thermal radical polymerization initiators include, for example, VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001, and V-501 (all manufactured by Wako Pure Chemical Industries, Ltd.). ) Etc. can be mentioned.

The content of the polymerization initiator has a preferable lower limit of 0.01 parts by weight and a preferable upper limit of 10 parts by weight with respect to 100 parts by weight of the polymerizable compound. When the content of the polymerization initiator is 0.01 parts by weight or more, the obtained sealing agent for an organic EL display element becomes more excellent in curability. When the content of the polymerization initiator is 10 parts by weight or less, the curing reaction of the obtained sealant for an organic EL display element does not become too fast, the workability is improved, and the cured product becomes more uniform. Can be. The more preferable lower limit of the content of the polymerization initiator is 0.05 parts by weight, and the more preferable upper limit is 5 parts by weight.

The encapsulant for an organic EL display element of the present invention may contain a sensitizer. The sensitizer has a role of further improving the polymerization initiation efficiency of the polymerization initiator and further promoting the curing reaction of the encapsulant for an organic EL display element of the present invention.

Examples of the sensitizer include thioxanthone compounds such as 2,4-diethylthioxanthone, 2,2-dimethoxy-1,2-diphenylethan-1-one, benzophenone, 2,4-dichlorobenzophenone, o-. Examples thereof include methyl benzoyl benzoate, 4,4'-bis (dimethylamino) benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide and the like.

Regarding the content of the sensitizer, the preferable lower limit is 0.01 part by weight and the preferable upper limit is 3 parts by weight with respect to 100 parts by weight of the polymerizable compound. When the content of the sensitizer is 0.01 parts by weight or more, the sensitizing effect is more exhibited. When the content of the sensitizer is 3 parts by weight or less, light can be transmitted to a deep part without excessive absorption. The more preferable lower limit of the content of the sensitizer is 0.1 parts by weight, and the more preferable upper limit is 1 part by weight.

The encapsulant for an organic EL display element of the present invention may contain a silane coupling agent. The silane coupling agent has a role of improving the adhesiveness between the sealing agent for an organic EL display element of the present invention and a substrate or the like.

Examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-isocyanatepropyltrimethoxysilane and the like. These silane compounds may be used alone or in combination of two or more.

Regarding the content of the silane coupling agent, the preferable lower limit is 0.1 part by weight and the preferable upper limit is 10 parts by weight with respect to 100 parts by weight of the polymerizable compound. When the content of the silane coupling agent is in this range, the effect of improving the adhesiveness while suppressing the bleed-out of the excess silane coupling agent becomes more excellent. The more preferable lower limit of the content of the silane coupling agent is 0.5 parts by weight, and the more preferable upper limit is 5 parts by weight.

The encapsulant for an organic EL display element of the present invention may further contain a surface modifier as long as the object of the present invention is not impaired. By containing the above-mentioned surface modifier, the flatness of the coating film can be imparted to the sealing agent for the organic EL display element of the present invention.
Examples of the surface modifier include a surfactant, a leveling agent and the like.

Examples of the surface modifier include silicone-based and fluorine-based agents.
Examples of commercially available surface modifiers include BYK-340, BYK-345 (all manufactured by Big Chemie Japan), Surflon S-611 (manufactured by AGC Seimi Chemical Co., Ltd.) and the like.

The encapsulant for an organic EL display element of the present invention may contain a solvent for the purpose of adjusting the viscosity, but there are problems such as deterioration of the organic light emitting material layer and generation of outgas due to the remaining solvent. It is preferable that the solvent is not contained or the solvent content is 0.05% by weight or less.

Further, the sealing agent for an organic EL display element of the present invention contains various known additives such as a reinforcing agent, a softening agent, a plasticizer, a viscosity modifier, an ultraviolet absorber, and an antioxidant, if necessary. May be.

As a method for producing the sealant for an organic EL display element of the present invention, for example, a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, or a three-roll is used to obtain a polymerizable compound. , A method of mixing the polymerization initiator and an additive such as a silane coupling agent to be added as needed can be mentioned.

The preferable lower limit of the total light transmittance of light at a wavelength of 380 to 800 nm of the cured product of the sealant for an organic EL display element of the present invention is 80%. When the total light transmittance is 80% or more, the obtained organic EL display element is superior in optical characteristics. A more preferable lower limit of the total light transmittance is 85%.
The total light transmittance can be measured using, for example, a spectroscope such as AUTOMATIC HAZE MATE MODEL TC = III DPK (manufactured by Tokyo Denshoku Co., Ltd.).
The cured product used for measuring the total light transmittance can be obtained by, for example, irradiating the sealant with ultraviolet rays having a wavelength of 365 nm at 3000 mJ / cm ² if it is a photocurable sealant. A thermosetting encapsulant can be obtained, for example, by heating at 80 ° C. for 1 hour.

The encapsulant for an organic EL display element of the present invention preferably has a transmittance of 85% or more at an optical path length of 20 μm at 400 nm after irradiating the cured product with ultraviolet rays for 100 hours. When the transmittance after irradiation with the ultraviolet rays for 100 hours is 85% or more, the transparency is high, the loss of light emission is small, and the color reproducibility is excellent. A more preferable lower limit of the transmittance after irradiation with the ultraviolet rays for 100 hours is 90%, and a further preferable lower limit is 95%.
As the light source for irradiating the ultraviolet rays, a conventionally known light source such as a xenon lamp or a carbon arc lamp can be used.
If the cured product used for measuring the transmittance after irradiation with the above ultraviolet rays for 100 hours is a photocurable sealant, for example, an ultraviolet ray having a wavelength of 365 nm is applied to the sealant with an LED lamp at 3000 mJ / cm. It can be obtained by irradiating with ² irradiations, and if it is a thermosetting encapsulant, it can be obtained by heating at 80 ° C. for 1 hour, for example.

The encapsulant for an organic EL display element of the present invention has a moisture permeability of 100 g / g at a thickness of 100 μm measured by exposing a cured product to an environment of 85 ° C. and 85% RH for 24 hours in accordance with JIS Z 0208. It is preferably m ² or less. When the moisture permeability is 100 g / m ² or less, the effect of preventing moisture from reaching the organic light emitting material layer and generating dark spots becomes more excellent, and the obtained organic EL display element is more excellent in reliability. It becomes a thing.
The cured product used for measuring the moisture permeability can be obtained by, for example, irradiating the sealant with ultraviolet rays having a wavelength of 365 nm at 3000 mJ / cm ² if it is a photocurable sealant. A thermosetting encapsulant can be obtained, for example, by heating at 80 ° C. for 1 hour.

Further, the sealant for an organic EL display element of the present invention has a water content of less than 0.5% when the cured product is exposed to an environment of 85 ° C. and 85% RH for 24 hours. preferable. When the water content of the cured product is less than 0.5%, the effect of preventing deterioration of the organic light emitting material layer due to moisture in the cured product is more excellent, and the obtained organic EL display element is more reliable. It becomes. A more preferable upper limit of the water content of the cured product is 0.3%.
Examples of the method for measuring the water content include a method of obtaining by the Karl Fischer method according to JIS K 7251 and a method of obtaining the weight increment after water absorption according to JIS K 7209-2.
The cured product used for measuring the water content can be obtained by, for example, irradiating the sealant with ultraviolet rays having a wavelength of 365 nm at 3000 mJ / cm ² if it is a photocurable sealant. A thermosetting encapsulant can be obtained, for example, by heating at 80 ° C. for 1 hour.

The sealant for an organic EL display element of the present invention 1 is suitably used for coating by an inkjet method, and the sealant for an organic EL display element of the present invention 2 is used for coating by an inkjet method.
As a method for manufacturing an organic EL display element using the sealant for an organic EL display element of the present invention, for example, a step of applying the sealant for an organic EL display element of the present invention to a substrate by an inkjet method. Examples thereof include a method having a step of curing the applied sealing agent for an organic EL display element by light irradiation and / or heating.

In the step of applying the sealing agent for an organic EL display element of the present invention to a base material, the sealing agent for an organic EL display element of the present invention may be applied to the entire surface of the base material, or may be applied to a part of the base material. It may be applied. The shape of the sealing portion of the sealing agent for the organic EL display element of the present invention formed by coating is not particularly limited as long as it can protect the laminated body having the organic light emitting material layer from the outside air, and the laminated body is not particularly limited. The shape may be a shape that completely covers the body, a closed pattern may be formed in the peripheral portion of the laminated body, or a pattern having a partially opened portion in the peripheral portion of the laminated body may be formed. It may be formed.

When the sealant for an organic EL display element is cured by light irradiation, the sealant for an organic EL display element of the present invention irradiates light with a wavelength of 300 nm to 400 nm and an integrated light amount of 300 to 3000 mJ / cm ² . This can be suitably cured.

Examples of the light source for irradiating the sealant for the organic EL display element of the present invention with light include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an excima laser, a chemical lamp, a black light lamp, and a microwave. Excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LED lamps, fluorescent lamps, sunlight, electron beam irradiation devices and the like can be mentioned. These light sources may be used alone or in combination of two or more.
These light sources are appropriately selected according to the absorption wavelength of the photoradical polymerization initiator and the photocationic polymerization initiator.

Examples of the means for irradiating the sealant for an organic EL display element of the present invention with light include simultaneous irradiation of various light sources, sequential irradiation with a time lag, combined irradiation of simultaneous irradiation and sequential irradiation, and the like. Any irradiation means may be used.

The cured product obtained by the step of curing the sealant for an organic EL display element by light irradiation and / or heating may be further coated with an inorganic material film.
As the inorganic material constituting the inorganic material film, conventionally known materials can be used, and examples thereof include silicon nitride (SiN _x ) and silicon oxide (SiO _x ). The inorganic material film may be composed of one layer or may be a laminated layer of a plurality of types. Further, the inorganic material film and the resin film made of the sealant for the organic EL display element of the present invention may be alternately repeated to coat the laminate.

The method for manufacturing the organic EL display element comprises a step of bonding a base material coated with the sealing agent for an organic EL display element of the present invention (hereinafter, also referred to as "one base material") and the other base material. You may have.
The base material (hereinafter, also referred to as “one base material”) to which the sealing agent for the organic EL display element of the present invention is applied may be a base material on which a laminate having an organic light emitting material layer is formed. , The base material on which the laminated body is not formed may be used.
When the one base material is a base material on which the laminated body is not formed, the present invention is applied to the one base material so that the laminated body can be protected from the outside air when the other base material is bonded. The sealant for the organic EL display element of the above may be applied. That is, either the entire surface is applied to the position of the laminated body when the other base material is bonded, or the position of the laminated body is completely formed when the other base material is bonded. A sealant portion having a closed pattern may be formed in a shape that fits within the shape of the sealant.

The step of curing the sealant for an organic EL display element by light irradiation and / or heating may be performed before the step of bonding the one base material and the other base material, or one of the above. It may be performed after the step of bonding the base material and the other base material.
When the step of curing the sealant for an organic EL display element by light irradiation and / or heating is performed before the step of bonding the one base material and the other base material, the organic EL display of the present invention is performed. The element encapsulant preferably has a pot life of 1 minute or more from light irradiation and / or heating until the curing reaction proceeds and adhesion cannot be achieved. When the pot life is 1 minute or more, higher adhesive strength can be obtained without excessive curing before the one base material and the other base material are bonded together.

In the step of bonding the one base material and the other base material, the method of bonding the one base material and the other base material is not particularly limited, but it is preferable to bond them in a reduced pressure atmosphere.
The preferable lower limit of the degree of vacuum under the reduced pressure atmosphere is 0.01 kPa, and the preferable upper limit is 10 kPa. When the degree of vacuum under the reduced pressure atmosphere is within this range, one of the base materials and the other base can be used without spending a long time to achieve a vacuum state due to the airtightness of the vacuum device and the capacity of the vacuum pump. It is possible to more efficiently remove air bubbles in the encapsulant for an organic EL display element of the present invention when the material is bonded.

According to the present invention, there is provided a sealing agent for an organic EL display element that can be easily applied by an inkjet method, has excellent low outgassing properties, and can obtain an organic EL display element having excellent reliability. Can be done.

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

(Examples 1 to 6, Comparative Examples 1 to 4)
According to the compounding ratio shown in Table 1, each material is uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring and mixing machine (manufactured by Primix Corporation, “Homodisper L type”). The encapsulants for each of the organic EL display elements of No. 6 and Comparative Examples 1 to 4 were produced.
The sealants for organic EL display elements obtained in Examples and Comparative Examples were measured using an E-type viscometer (“VISCOMETER TV-22” manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and 100 rpm. Table 1 shows the viscosity and the surface tension measured by a dynamic wettability tester (“WET-6100 type” manufactured by Resca) at 25 ° C.
Further, about 10 g of the sealant for each organic EL display element obtained in Examples and Comparative Examples was placed in a plastic brown container having a diameter of 33 mm and a capacity of 50 mL, and the weight (A) was measured. The weight (B) of the container after being left as it was for 4 days without a lid under a yellow lamp environment of atmospheric pressure and 50% RH was measured, and the volatilization rate after 4 days at 25 ° C. was calculated by the above formula. The results are shown in Table 1.

<Evaluation>
The following evaluations were performed on the sealants for each organic EL display element obtained in Examples and Comparative Examples. The results are shown in Table 1.
In each evaluation of inkjet ejection property, ejection stability, wet spreading property, and reliability of the organic EL display element, IJH-30 (manufactured by IJT) was used as the coating head for inkjet, and heating was used for inkjet coating. It was done without doing it (head temperature 25 ° C.).

(1) Inkjet coating property (1-1) Inkjet ejection property A sealing agent for each organic EL display element obtained in Examples and Comparative Examples is used with an inkjet ejection device (“NanoPrinter500” manufactured by Microjet Co., Ltd.). , 30 picolitres of droplets were applied onto alkali-cleaned non-alkali glass (“AN100” manufactured by Asahi Glass Co., Ltd.). The inkjet ejection property was evaluated as "◯" when the droplet was normally ejected from the inkjet nozzle and landed on the substrate, and "x" when the droplet was not ejected normally.

(1-2) Discharge Stability Using an inkjet ejection device (“NanoPrinter500” manufactured by Microjet Co., Ltd.), the sealants for each organic EL display element obtained in Examples 1 to 6 and Comparative Examples 3 and 4 were used. , 1000 drops were applied at a rate of 5 m / sec at a pitch of 500 μm on a non-alkali glass (manufactured by Asahi Glass Co., Ltd., “AN100”) that had been alkaline-cleaned with a droplet volume of 30 picolitres. Then, after leaving it at 25 ° C. for 10 minutes, the coating was applied again under the same conditions as above, and the state of the droplets on the glass substrate after the second coating was observed.
"○" when the number of droplets that could not be applied was 0, "△" when the number of droplets that could not be applied was less than 20, and the number of droplets that could not be applied When the number was 20 or more, the discharge stability was evaluated as "x".

(1-3) Wetting and spreading property The sealants for organic EL display elements obtained in Examples 1 to 6 and Comparative Examples 3 and 4 are used with an inkjet ejection device (“NanoPrinter500” manufactured by Microjet Co., Ltd.). , 1000 drops were applied at a rate of 5 m / sec at a pitch of 500 μm on a non-alkali glass (manufactured by Asahi Glass Co., Ltd., “AN100”) washed with an alkali with a droplet volume of 30 picolitres. The diameter of the droplet on the non-alkali glass 10 minutes after application was measured, and the case where the diameter of the droplet was 150 μm or more was “○”, and the case where the diameter of the droplet was 50 μm or more and less than 150 μm was “○”. The wet spreadability was evaluated as "Δ" and "x" when the diameter of the droplet was less than 50 μm.

(2) Low outgas properties A gas chromatograph by the headspace method (manufactured by JEOL Ltd.) is used to capture the outgas generated during heating of the cured product of the sealant for each organic EL display element obtained in Examples 1 to 6 and Comparative Examples 3 and 4. , "JMS-Q1050GC"). 100 mg of a sealing agent for each organic EL display element was applied to a thickness of 300 μm with an applicator. Next, the sealant was cured by irradiating the sealant with ultraviolet rays having a wavelength of 365 nm at 3000 mJ / cm ² with an LED lamp, and then the cured sealant was placed in a headspace vial to seal the vial at 100 ° C. The generated gas was measured by the headspace method.
The low outgas property was evaluated as "◯" when the generated gas was less than 300 ppm, "Δ" when it was 300 ppm or more and less than 500 ppm, and "x" when it was 500 ppm or more.

(3) Reliability of organic EL display element (3-1) Fabrication of a substrate on which a laminate having an organic light emitting material layer is arranged An ITO electrode is placed on a glass substrate (length 25 mm, width 25 mm, thickness 0.7 mm). A film formed with a thickness of 1000 Å was used as a substrate. The substrate is ultrasonically washed with acetone, an alkaline aqueous solution, ion-exchanged water, and isopropyl alcohol for 15 minutes each, then washed with boiling isopropyl alcohol for 10 minutes, and further, a UV-ozone cleaner (manufactured by Nippon Laser Electronics Co., Ltd.). Immediate treatment was performed with "NL-UV253").
Next, this substrate was fixed to the substrate folder of the vacuum vapor deposition apparatus, and 200 mg of N, N'-di (1-naphthyl) -N, N'-diphenylbenzidine (α-NPD) was added to the unglazed crucible for another unglazed. 200 mg of tris (8-quinolinolat) aluminum (Alq ₃ ) was placed in the crucible, and the pressure inside the vacuum chamber was reduced to 1 × 10 ^-4 Pa. Then, the crucible containing α-NPD was heated, α-NPD was deposited on the substrate at a vapor deposition rate of 15 Å / s, and a hole transport layer having a film thickness of 600 Å was formed. Next, the crucible containing Alq ₃ was heated to form an organic light emitting material layer having a film thickness of 600 Å at a vapor deposition rate of 15 Å / s. After that, the substrate on which the hole transport layer and the organic light emitting material layer were formed was transferred to another vacuum vapor deposition apparatus, and lithium fluoride 200 mg was transferred to a tungsten resistance heating boat in this vacuum vapor deposition apparatus, and aluminum wire was transferred to another tungsten boat. 1.0 g was added. Then, the inside of the vapor deposition device of the vacuum vapor deposition apparatus is depressurized to 2 × 10 ^-4 Pa to form 5 Å of lithium fluoride at a vapor deposition rate of 0.2 Å / s, and then 1000 Å of aluminum at a rate of 20 Å / s. did. The inside of the vapor deposition apparatus was returned to normal pressure with nitrogen, and the substrate on which the laminate having the organic light emitting material layer of 10 mm × 10 mm was arranged was taken out.

(3-2) Covering with Inorganic Material Membrane A A mask having an opening of 13 mm × 13 mm is installed so as to cover the entire laminated body of the substrate on which the obtained laminated body is arranged, and it is inorganic by a plasma CVD method. The material film A was formed.
In the plasma CVD method, SiH ₄ gas and nitrogen gas are used as raw material gases, the respective flow rates are SiH ₄ gas 10 sccm and nitrogen gas 200 sccm, RF power is 10 W (frequency 2.45 GHz), chamber temperature is 100 ° C, and chamber. The procedure was performed under the condition that the internal pressure was 0.9 Torr.
The thickness of the formed inorganic material film A was about 1 μm.

(3-3) Formation of Resin Protective Film On the obtained substrate, the sealants for each organic EL display element obtained in Examples 1 to 6 and Comparative Examples 3 and 4 are applied to an inkjet ejection device (Microjet Co., Ltd.). The pattern was applied to the substrate using "NanoPrinter500").
Then, using an LED lamp, ultraviolet rays having a wavelength of 365 nm were irradiated at 3000 mJ / cm ² to cure the sealant for the organic EL display element to form a resin protective film.

(3-4) Covering with Inorganic Material Film B After forming the resin protective film, a mask having an opening of 12 mm × 12 mm is installed so as to cover the entire resin protective film, and the inorganic material is subjected to plasma CVD method. A film B was formed to obtain an organic EL display element.
The plasma CVD method was carried out under the same conditions as in the above-mentioned "(3-2) Coating with inorganic material film A".
The thickness of the formed inorganic material film B was about 1 μm.

(3-5) Quenching State of Organic EL Display Element After exposing the obtained organic EL display element for 100 hours in an environment of temperature 85 ° C. and humidity 85%, a voltage of 3 V is applied to the organic EL display element. The light emission state (presence or absence of dark spots and quenching around the pixels) was visually observed. "○" when there is no dark spot or peripheral quenching and uniform emission, "△" when there is no dark spot or peripheral quenching but a slight decrease in brightness is observed, and when dark spot or peripheral quenching is observed. Was set to "x" to evaluate the display performance of the organic EL display element.

The following experiments were conducted in order to confirm the effect of the viscosity of the sealant for an organic EL display element on the inkjet coatability in the non-heated inkjet method and the heated inkjet method. The results are shown in Table 2.

(Experimental Example 1)
According to the compounding ratios shown in Table 2, each material was uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring and mixing machine (manufactured by Primix Corporation, "homodisper L type"), and then at 50 ° C. and 0 ° C. A sealing agent for an organic EL display element was produced by performing a dehydration step of exposing to an environment of 1 MPa for 30 minutes.
The obtained sealant for organic EL display element was measured with an E-type viscometer (“VISCOMETER TV-22” manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and 100 rpm, and the viscosity and 25 ° C. The surface tension was measured with a dynamic wettability tester (manufactured by Resca, "WET-6100 type").
Further, in a plastic brown container having a diameter of 33 mm and a capacity of 50 mL, about 10 g of the obtained sealing agent for an organic EL display element was placed and the weight (A) was measured. The weight (B) of the container after being left as it was for 4 days without a lid in a lamp environment was measured, and the volatilization rate after 4 days at 25 ° C. was calculated by the above formula.
The obtained sealing agent for an organic EL display element was alkaline-cleaned with an inkjet ejection device (“NanoPrinter500” manufactured by Microjet Co., Ltd.) with a droplet volume of 30 picolitres (manufactured by Asahi Glass Co., Ltd.). , "AN100"). The inkjet ejection property was evaluated as "◯" when the droplet was normally ejected from the inkjet nozzle and landed on the substrate, and "x" when the droplet was not ejected normally. IJH-30 (manufactured by IJT) was used as the coating head for inkjet, and the inkjet coating was performed without heating (head temperature 25 ° C.).

(Experimental Example 2)
The same encapsulant for an organic EL display element as that produced in Experimental Example 1 was prepared.
An inkjet ejection property was evaluated in the same manner as in Experimental Example 1 except that IJH-30 (manufactured by IJT) was used as an inkjet coating head and inkjet coating was performed while heating (head temperature 60 ° C.).

According to the present invention, there is provided a sealing agent for an organic EL display element that can be easily applied by an inkjet method, has excellent low outgassing properties, and can obtain an organic EL display element having excellent reliability. Can be done.

Claims (4)

Contains a polymerizable compound and a polymerization initiator,
An organic EL display element having a viscosity at 25 ° C. of 5 to 50 mPa · s, a surface tension of 15 to 35 mN / m at 25 ° C., and a volatilization rate of 1% or less after 4 days at 25 ° C. Sealant for. A sealant for organic EL display elements used for coating by the inkjet method.
Contains a polymerizable compound and a polymerization initiator,
A sealing agent for an organic EL display element, characterized in that the volatilization rate after 4 days at 25 ° C. is 1% or less. The sealant for an organic EL display element according to claim 1 or 2, wherein the polymerizable compound contains a compound having a boiling point of 160 ° C. or higher in an amount of 95 parts by weight or more in 100 parts by weight of the entire polymerizable compound. The sealant for an organic EL display element according to claim 1, 2 or 3, wherein the solvent is not contained, or the content of the solvent is 0.05% by weight or less.