JP6404495B2 - Sealant for organic EL display element - Google Patents

Description

The present invention relates to a sealant for an organic EL display element that can be easily applied by an ink jet method, can obtain a cured product that is excellent in low outgassing properties and excellent in bending resistance.

An 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 formed from one electrode on the organic light emitting material layer. When electrons are injected and holes are injected from the other electrode, the electrons and holes are combined in the organic light emitting material layer to emit light. Thus, since the organic EL display 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. Has the advantage.

The organic light-emitting material layer and electrodes constituting the organic EL display element have a problem that the 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 extend the life by blocking the organic light emitting material layer and the electrode from the atmosphere. Patent Document 1 discloses a method of sealing an organic light emitting material layer and an electrode of an organic EL display element 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 the electrode due to internal stress of the silicon nitride film.

In the method of sealing with a silicon nitride film disclosed in Patent Document 1, organic light emission occurs when a silicon nitride film is formed due to unevenness on the surface of the organic EL display element, adhesion of foreign matters, generation of cracks due to internal stress, or the like. The material layer or electrode may not be completely covered. If the coating with the silicon nitride film is incomplete, moisture will enter the organic light emitting material layer through the silicon nitride film.
As a method for preventing moisture from entering into the organic light emitting material layer, Patent Document 2 discloses a method of alternately depositing an inorganic material film and a resin film. Patent Document 3 and Patent Document 4 Discloses a method of forming a resin film on an inorganic material film.

As a method for forming a resin film, there is a method in which a sealing agent is applied on a substrate using an inkjet method and then the sealing agent is cured. If such a coating method by the ink jet method is used, a resin film can be uniformly formed at high speed. However, when the sealant is made to have a low viscosity in order to be suitable for application by the ink jet method, there is a problem that outgas is likely to occur. In addition, when a conventional sealant is used, cracks or peeling occurs in the cured product of the sealant due to bending or the like during use, and the ingress of moisture cannot be sufficiently prevented, and the resulting organic EL display There was a problem that an element may be inferior in reliability.

JP 2000-223264 A JP 2005-522891 A JP 2001-307873 A JP 2008-149710 A

An object of the present invention is to provide a sealant for an organic EL display element that can be easily applied by an ink jet method, can obtain a cured product that is excellent in low outgassing properties and excellent in bending resistance. To do.

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 a cured product at 25 ° C. It is a sealing agent for organic EL display elements having a Poisson's ratio of 0.28 to 0.40.
In addition, the present invention 2 is an organic EL display element sealing agent used for coating by an ink jet method, which contains a polymerizable compound and a polymerization initiator, and has a Poisson's ratio at 25 ° C. of 0.28 of the cured product. It is the sealing agent for organic EL display elements which is -0.40.
The present invention is described in detail below. In addition, about the matter common to the sealing agent for organic EL display elements of this invention 1 and the sealing agent for organic EL display elements of this invention 2, it describes as "the sealing agent for organic EL display elements of this invention". To do.

The inventors of the present invention further studied that the Poisson's ratio of the cured product at 25 ° C. falls within a specific range for the sealing agent for organic EL display elements having excellent ink jet coatability. As a result, it was found that an encapsulant for organic EL display elements that can be easily applied by an ink jet method, has excellent low outgassing properties, and can obtain a cured product having excellent bending resistance, can be obtained. The present invention has been completed.

The sealing agent for organic EL display elements of the present invention can be used as an ink jet method for coating by a non-heated ink jet method, or can be used for coating by a heat ink jet method.
In the present specification, the “non-heated ink jet method” is a method of ink jet coating at a coating head temperature of less than 28 ° C., and the “heated ink jet method” is an ink jet at a coating head temperature of 28 ° C. or higher. It is a method of applying.

In the heating ink jet method, an ink jet coating head equipped with a heating mechanism is used. When the inkjet coating head is equipped with a heating mechanism, the viscosity and the surface tension can be lowered when discharging the sealing agent for organic EL display elements.

Examples of the inkjet coating head equipped with the heating mechanism include KM1024 series manufactured by Konica Minolta, SG1024 series manufactured by Fuji Film Dimatix, and the like.

When using the sealing agent for organic EL display elements of this invention for application | coating by the said heating-type inkjet method, it is preferable that the heating temperature of a coating head is the range of 28 to 80 degreeC. When the heating temperature of the coating head is within this range, the increase in the viscosity of the sealant for organic EL display elements over time is suppressed, and the ejection stability is improved.

The sealing agent for organic EL display elements of the present invention 1 has a viscosity lower limit of 5 mPa · s and an upper limit of 50 mPa · s. When the viscosity is within this range, it can be suitably applied by an ink jet method.
In addition, the said viscosity in this specification means the value measured on 25 degreeC and 100 rpm conditions using an E-type viscosity meter.

The preferable lower limit of the viscosity of the sealing agent for organic EL display elements of the present invention when applied by the non-heating ink jet method is 5 mPa · s, and the preferable upper limit is 20 mPa.s. s. When the viscosity is within this range, it can be suitably applied by a non-heating ink jet method. The more preferable lower limit of the viscosity of the sealing agent for organic EL display elements of the present invention when applied by the non-heating ink jet method is 8 mPa · s, and the more preferable upper limit is 16 mPa · s. s, a more preferred lower limit is 10 mPa · s, and a more preferred upper limit is 13 mPa · s. s.

On the other hand, the preferable lower limit of the viscosity of the sealing agent for organic EL display elements of the present invention when used for coating by the heating ink jet method is 10 mPa · s and the preferable upper limit is 50 mPa. s. When the viscosity is within this range, it can be suitably applied by a heating ink jet method. The more preferable lower limit of the viscosity of the sealing agent for organic EL display elements of the present invention when used for coating by the heating ink jet method is 20 mPa · s, and the more preferable upper limit is 40 mPa · s. s.

The sealing agent for organic EL display elements 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 within this range, it can be suitably applied by an ink jet 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.
Moreover, the sealing agent for organic EL display elements of the present invention 2 has a preferable lower limit of surface tension of 15 mN / m and a preferable upper limit of 35 mN / m. When the surface tension is within this range, it can be suitably applied by an ink jet method. The more preferable lower limit of the surface tension is 20 mN / m, the more preferable upper limit is 30 mN / m, the still more preferable lower limit is 22 mN / m, and the still more preferable upper limit is 28 mN / m.
The surface tension means a value measured by a Wilhelmy method using a dynamic wettability tester at 25 ° C.

As for the sealing agent for organic EL display elements of this invention, the minimum of the Poisson's ratio in 25 degreeC of hardened | cured material is 0.28, and an upper limit is 0.40. When the Poisson's ratio is 0.28 or more, the effect of preventing the occurrence of cracks when the cured product is bent is excellent. When the Poisson's ratio is 0.40 or less, the effect of preventing the occurrence of warpage of the cured product is excellent. The preferable lower limit of the Poisson's ratio is 0.30, the preferable upper limit is 0.36, the more preferable lower limit is 0.33, and the more preferable upper limit is 0.35.
In the present specification, the Poisson's ratio is defined as a distortion in a direction in which a force is applied and a distortion in a direction orthogonal to the direction in which the force is applied when the force is elastically deformed by applying a force in a uniaxial direction of the object. Means ratio. In the Poisson's ratio, the length before elastic deformation in the direction in which the force is applied is p, the change in length due to the elastic deformation in the direction in which the force is applied is Δp, and the elastic deformation in the direction perpendicular to the direction in which the force is applied When the previous length is r, and the amount of change in length due to elastic deformation in the direction orthogonal to the direction in which the force is applied is Δr, it can be obtained by the following equation.
Poisson's ratio = (Δr / r) / (Δp / p)
Moreover, if the hardened | cured material used for the measurement of the said Poisson's ratio is a photocurable sealing agent, for example, it can obtain by irradiating 3000 mJ / cm < ² > of ultraviolet rays with a wavelength of 365 nm with a LED lamp to sealing agent. If it is a thermosetting sealing agent, it can obtain by heating at 80 degreeC for 1 hour, for example.

The lower limit of the Young's modulus at 25 ° C. of the cured product of the sealant for organic EL display elements of the present invention is 1500 MPa, and the upper limit is 5000 MPa. When the Young's modulus is within this range, the effect of preventing the occurrence of cracks when the cured product is bent is excellent. A preferable lower limit of the Young's modulus is 2700 MPa, a preferable upper limit is 4000 MPa, a more preferable lower limit is 3000 MPa, and a more preferable upper limit is 3500 MPa.
In the present specification, the Young's modulus means a value measured under the conditions of 25 ° C., 50% RH, and distance between chucks of 100 mm by a method based on JIS K 7127-1989.
Moreover, if the hardened | cured material used for the measurement of the said Young's modulus is a photocurable sealing agent, it can obtain by irradiating 3000 mJ / cm < ² > of ultraviolet rays with a wavelength of 365 nm with a LED lamp to a sealing agent, for example. If it is a thermosetting sealing agent, it can obtain by heating at 80 degreeC for 1 hour, for example.

The viscosity, the surface tension, the Poisson's ratio, and the Young's modulus are selected from the following types of polymerizable compounds, polymerization initiators, and other components that may be contained. By adjustment, the above-mentioned range can be obtained.

The sealing agent for organic EL display elements of the present invention contains a polymerizable compound.
As the polymerizable compound, a radical polymerizable compound or a cationic polymerizable compound can be used. Of these, radically polymerizable compounds are preferred.

As the radical 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. The monofunctional (meth) acrylic compound and the polyfunctional (meth) You may use it in combination with an acrylic compound.
In the present specification, the above “(meth) acryl” means acryl or methacryl, the above “(meth) acryl compound” means a compound having a (meth) acryloyl group, and the above “(meth) “Acryloyl” means acryloyl or methacryloyl.

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

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. Acid 2- (2-vinyloxyethoxy) ethyl, 3-ethyl-3- (meth) acryloxymethyloxetane, allyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (Meth) acrylate, ethoxytriethylene glycol (meth) acrylate, 2- (2-vinyloxyethoxy) ethyl (meth) acrylate and the like. 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 “(meth) acrylate” means acrylate or methacrylate.

When the polymerizable compound contains the monofunctional (meth) acrylic compound, the preferred 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 preferred upper limit is 80. Parts by weight. When the content of the monofunctional (meth) acrylic compound is within this range, the obtained sealing agent for organic EL display elements is excellent due to low outgassing properties and the like. The minimum with more preferable content of the said monofunctional (meth) acryl compound is 30 weight part, and a more preferable upper limit is 60 weight part.

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

The polyfunctional (meth) acrylic compound preferably has a structure with less carbon chain branching, and more preferably is a straight chain, from the viewpoint of inkjet coating properties and the like.

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, tetrapropylene glycol di (meth) acrylate is preferable.

When the polymerizable compound contains the polyfunctional (meth) acrylic compound, the preferred 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 preferred upper limit is 80. Parts by weight. When the content of the polyfunctional (meth) acrylic compound is within this range, the obtained sealing agent for organic EL display elements is excellent in ink jet coating properties and the like. The minimum with more preferable content of the said polyfunctional (meth) acryl compound is 30 weight part, and a more preferable upper limit is 60 weight part.

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 expressed as a weight ratio. Monofunctional (meth) acrylic compound: polyfunctional (meth) acrylic compound = 7: 3 to 3: 7 is preferable. By setting the content ratio of the monofunctional (meth) acrylic compound and the polyfunctional (meth) acrylic compound in this range, the obtained sealing agent for organic EL display elements is excellent in ink jet coating properties and the like. be able to. The content ratio of the monofunctional (meth) acrylic compound and the polyfunctional (meth) acrylic compound is a weight ratio of monofunctional (meth) acrylic compound: polyfunctional (meth) acrylic compound = 6: 4 to 4: 6. It is more preferable that

As said cationically polymerizable compound, an epoxy compound, an oxetane compound, a vinyl ether compound etc. are mentioned, for example.

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, 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 Epoxy resin, phenol novolac epoxy resin, orthocresol novolac epoxy resin, dicyclopentadiene novolac epoxy resin, biphenyl Examples thereof include a volac type epoxy resin, a naphthalene phenol novolac type epoxy resin, a glycidyl amine type epoxy resin, an alkyl polyol type epoxy resin, a rubber-modified epoxy resin, a glycidyl ester compound, and an epoxy-modified organopolysiloxane. Of these, alicyclic epoxy resins are preferred.
Examples of commercially available alicyclic epoxy resins include Celoxide 2000, Celoxide 2021P, Celoxide 2081, Celoxide 3000, Celoxide 8000 (all manufactured by Daicel), and Sunsizer EPS (manufactured by Shin Nippon Rika Kogyo Co., Ltd.). ) And the like.

Examples of the oxetane compound include allyloxyoxetane, phenoxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 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, Oxetanylsilsesquioxane, phenol novolac oxetane, 1,4-bis (((3-ethyl-3-oxetanyl) methoxy) methyl) benzene, and the like can be given.

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

The sealing agent for organic EL display elements of the present invention contains a polymerization initiator.
As the polymerization initiator, a radical photopolymerization initiator, a thermal radical polymerization initiator, a cationic photopolymerization initiator, or a thermal cationic polymerization initiator is suitably used depending on the type of polymerizable compound used.

Examples of the photo radical polymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, benzyl, thioxanthone compounds, and the like.

Examples of commercially available photo radical polymerization initiators include IRGACURE 184, IRGACURE 369, IRGACURE 379, IRGACURE 651, IRGACURE 819, IRGACURE 907, IRGACURE 2959, IRGACURE OXE01, and Lucin TPO (both benzoin methyl ether, benzoin methyl ether) Examples include ethyl ether and benzoin isopropyl ether (both manufactured by Tokyo Chemical Industry Co., Ltd.).

As said thermal radical polymerization initiator, what consists of an azo compound, an organic peroxide, etc. is mentioned, for example.
Examples of the azo compound include 2,2′-azobis (2,4-dimethylvaleronitrile) and azobisisobutyronitrile.
Examples of the organic peroxide include benzoyl peroxide, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxyester, diacyl peroxide, and peroxydicarbonate.

Examples of commercially available thermal radical polymerization initiators include VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001, and V-501 (all manufactured by Wako Pure Chemical Industries, Ltd.). ) And the like.

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

Examples of the anion portion of the ionic photoacid-generating photocationic polymerization initiator include BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , and (BX ₄ ) ⁻ (wherein X is at least two or more. And a phenyl group substituted with a fluorine or trifluoromethyl group).
Examples of the ionic photoacid-generating photocationic polymerization initiator include aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, aromatic ammonium salts having the anion moiety, (2,4-cyclo And pentadien-1-yl) ((1-methylethyl) benzene) -Fe salt.

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 hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis (4- (di ( 4- (2-hydroxyethoxy)) phenylsulfonio) 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 ( - (2-hydroxyethoxy)) phenylsulfonio) phenyl) sulfide tetrakis (pentafluorophenyl) borate, tris (4- (4-acetylphenyl) thiophenyl) sulfonium tetrakis (pentafluorophenyl) borate, and the like.

Examples of the aromatic iodonium salt include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, bis (dodecylphenyl) iodonium hexafluorophosphate, bis (Dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexa Fluorophosphate, 4-methylphenyl-4- (1-methylethyl) Such as phenyl iodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrafluoroborate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrakis (pentafluorophenyl) borate 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) borate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, 1- (naphthylmethyl) Examples include 2-cyanopyridinium tetrafluoroborate and 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) borate.

Examples of the (2,4-cyclopentadien-1-yl) ((1-methylethyl) benzene) -Fe salt include (2,4-cyclopentadien-1-yl) ((1-methylethyl) benzene. ) -Fe (II) hexafluorophosphate, (2,4-cyclopentadiene-1-yl) ((1-methylethyl) benzene) -Fe (II) hexafluoroantimonate, (2,4-cyclopentadiene-1 -Yl) ((1-methylethyl) benzene) -Fe (II) tetrafluoroborate, (2,4-cyclopentadien-1-yl) ((1-methylethyl) benzene) -Fe (II) tetrakis (penta Fluorophenyl) borate and the like.

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

Examples of 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, SP-170 (all ADEKA), FC-508, FC-512 (all from 3M), IRGACURE261, IRGACURE290 (all from BASF), PI2074 (from Rhodia), and the like.

As the thermal cationic polymerization initiator, the anion moiety is BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , or (BX ₄ ) ⁻ (where X is substituted with at least two fluorine or trifluoromethyl groups. A sulfonium salt, a phosphonium salt, an ammonium salt, and the like. 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 Safluoroantimonate, methylphenyldibenzylammonium tetrakis (pentafluorophenyl) borate, phenyltribenzylammonium tetrakis (pentafluorophenyl) borate, dimethylphenyl (3,4-dimethylbenzyl) 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 etc. are mentioned.

Examples of 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 Sanshin Chemical Industries, Ltd. Product), CXC1612, CXC1821 (all manufactured by King Industries) and the like.

The content of the polymerization initiator is preferably 0.01 parts by weight and preferably 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 organic EL display elements is more excellent in curability. When the content of the polymerization initiator is 10 parts by weight or less, the curing reaction of the obtained sealing agent for organic EL display elements does not become too fast, and the workability is improved, and the cured product is more uniform. It can be. The minimum with more preferable content of the said polymerization initiator is 0.05 weight part, and a more preferable upper limit is 5 weight part.

The sealing agent for organic EL display elements 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 sealing agent for organic EL display elements of the present invention.

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

The content of the sensitizer is preferably 0.01 parts by weight and preferably 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 minimum with more preferable content of the said sensitizer is 0.1 weight part, and a more preferable upper limit is 1 weight part.

The sealing agent for organic EL display elements of the present invention may contain a silane coupling agent. The said silane coupling agent has a role which improves the adhesiveness of the sealing agent for organic EL display elements of this invention, and a board | substrate.

Examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-isocyanatopropyltrimethoxysilane. These silane coupling agents may be used independently and 2 or more types may be used together.

The content of the silane coupling agent is preferably 0.1 parts by weight and preferably 10 parts by weight with respect to 100 parts by weight of the polymerizable compound. When the content of the silane coupling agent is within this range, the effect of improving the adhesiveness is suppressed while suppressing the excess silane coupling agent from bleeding out. The minimum with more preferable content of the said silane coupling agent is 0.5 weight part, and a more preferable upper limit is 5 weight part.

The sealing agent for organic EL display elements 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 surface modifier, the flatness of the coating film can be imparted to the organic EL display element sealant of the present invention.
Examples of the surface modifier include surfactants and leveling agents.

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

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

Moreover, the sealing agent for organic EL display elements of this invention contains well-known various additives, such as a reinforcing agent, a softening agent, a plasticizer, a viscosity modifier, a ultraviolet absorber, antioxidant, as needed. May be.

Examples of the method for producing the sealing agent for organic EL display elements of the present invention include a polymerizable compound using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, and a three roll. And a method of mixing a polymerization initiator and an additive such as a silane coupling agent added if necessary.

A preferred lower limit of the total light transmittance of light at a wavelength of 380 to 800 nm of the cured product of the encapsulant for organic EL display elements of the present invention is 80%. When the total light transmittance is 80% or more, the obtained organic EL display element has superior optical characteristics. A more preferable lower limit of the total light transmittance is 85%.
The total light transmittance can be measured using a spectrometer such as AUTOMATIC HAZE MATER MODEL TC = III DPK (manufactured by Tokyo Denshoku Co., Ltd.).
Moreover, if the hardened | cured material used for the measurement of the said total light transmittance is a photocurable sealing agent, it will obtain by irradiating 3000 mJ / cm < ² > of ultraviolet rays with a wavelength of 365 nm with a LED lamp to a sealing agent, for example. If it is a thermosetting sealant, it can be obtained by heating at 80 ° C. for 1 hour, for example.

In the sealing agent for organic EL display elements of the present invention, the transmittance at 400 nm after irradiating the cured product with ultraviolet rays for 100 hours is preferably 85% or more at an optical path length of 20 μm. When the transmittance after irradiating 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 more 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.
Moreover, if the hardened | cured material used for the measurement of the transmittance | permeability after irradiating the said ultraviolet-ray for 100 hours is a photocurable sealing agent, for example, ultraviolet rays with a wavelength of 365 nm will be 3000 mJ / cm with a LED lamp to sealing agent. ^If it is a thermosetting sealant, it can be obtained, for example, by heating at 80 ° C. for 1 hour.

The sealant for an organic EL display device of the present invention has a moisture permeability of 100 g / 100 μm when the cured product is exposed to an environment of 85 ° C. and 85% RH for 24 hours in accordance with JIS Z 0208. m is preferably 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 the generation of dark spots is improved, and the resulting organic EL display element is more reliable. It will be a thing.
Moreover, if the hardened | cured material used for the said moisture permeability measurement is a photocurable sealing agent, for example, it can obtain by irradiating 3000 mJ / cm < ² > of ultraviolet rays with a wavelength of 365 nm with a LED lamp to sealing agent. If it is a thermosetting sealing agent, it can obtain by heating at 80 degreeC for 1 hour, for example.

Furthermore, the sealing agent for organic EL display elements of the present invention may have a moisture 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 moisture content of the cured product is less than 0.5%, the effect of preventing the deterioration of the organic light emitting material layer due to moisture in the cured product is excellent, and the obtained organic EL display element is excellent in reliability. It becomes. A more preferable upper limit of the moisture content of the cured product is 0.3%.
Examples of the method for measuring the moisture content include a method of obtaining by a Karl Fischer method in accordance with JIS K 7251, and a method of obtaining a weight increment after water absorption in accordance with JIS K 7209-2.
Moreover, if the hardened | cured material used for the measurement of the said moisture content is a photocurable sealing agent, it can obtain by irradiating 3000 mJ / cm < ² > of ultraviolet rays with a wavelength of 365 nm with a LED lamp to a sealing agent, for example. If it is a thermosetting sealing agent, it can obtain by heating at 80 degreeC for 1 hour, for example.

The sealing agent for organic EL display elements of the present invention 1 is suitably used for coating by an ink jet method, and the sealing agent for organic EL display elements of the present invention 2 is used for coating by an ink jet method.
As a method for producing an organic EL display element using the sealing agent for organic EL display elements of the present invention, for example, a step of applying the sealing agent for organic EL display elements of the present invention to a substrate by an inkjet method, And a method of curing the applied sealing agent for organic EL display elements by light irradiation and / or heating.

In the step of applying the organic EL display element sealant of the present invention to the substrate, the organic EL display element sealant of the present invention may be applied to the entire surface of the substrate, or on a part of the substrate. It may be applied. The shape of the sealing portion of the sealing agent for organic EL display elements of the present invention formed by coating is not particularly limited as long as it is a shape that can protect the laminate having the organic light emitting material layer from the outside air. A shape that completely covers the body may be formed, a closed pattern may be formed in the peripheral portion of the laminate, or a pattern having a shape in which a partial opening is provided in the peripheral portion of the laminate. It may be formed.

When the sealing agent for organic EL display elements is cured by light irradiation, the sealing agent for organic EL display elements of the present invention irradiates light having a wavelength of 300 nm to 400 nm and an integrated light amount of 300 to 3000 mJ / cm ^2. Can be suitably cured.

Examples of the light source for irradiating the organic EL display element sealant of the present invention with light include 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, and a microwave. Examples include an excited mercury lamp, a metal halide lamp, a sodium lamp, a halogen lamp, a xenon lamp, an LED lamp, a fluorescent lamp, sunlight, and an electron beam irradiation device. These light sources may be used independently and 2 or more types may be used together.
These light sources are appropriately selected according to the absorption wavelength of the photo radical polymerization initiator or the photo cationic polymerization initiator.

Examples of the light irradiation means to the organic EL display element sealant of the present invention include simultaneous irradiation of various light sources, sequential irradiation with a time difference, 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 organic EL display element sealing agent by light irradiation and / or heating may be further coated with an inorganic material film.
As the inorganic material forming the inorganic material layer can be a conventionally known, for example, silicon nitride (SiN _x), silicon oxide (SiO _x), and the like. The inorganic material film may be a single layer or may be a laminate of a plurality of types of layers. Moreover, you may coat | cover the said laminated body by repeating alternately the said inorganic material film | membrane and the resin film which consists of the sealing agent for organic EL display elements of this invention.

The method for producing the organic EL display element comprises a step of bonding a base material (hereinafter also referred to as “one base material”) coated with the organic EL display element sealing agent of the present invention and the other base material. You may have.
The substrate on which the sealing agent for organic EL display elements of the present invention is applied (hereinafter also referred to as “one substrate”) may be a substrate on which a laminate having an organic light emitting material layer is formed. A base material on which the laminate is not formed may be used.
When the one substrate is a substrate on which the laminate is not formed, the present invention is applied to the one substrate so that the laminate can be protected from the outside air when the other substrate is bonded. What is necessary is just to apply | coat the sealing agent for organic EL display elements. That is, apply the entire surface to the location of the laminate when the other substrate is bonded, or the location of the laminate is complete when the other substrate is bonded. The sealing agent portion having a closed pattern may be formed in a shape that fits in the shape.

The step of curing the organic EL display element sealant by light irradiation and / or heating may be performed before the step of bonding the one base material and the other base material, You may perform after the process of bonding a base material and said other base material.
When the step of curing the organic EL display element sealant 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. The device sealant preferably has a pot life of 1 minute or longer after irradiation with light and / or heating until the curing reaction proceeds and adhesion becomes impossible. When the pot life is 1 minute or longer, higher adhesion 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, a 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 in the reduced-pressure atmosphere is 0.01 kPa, and the preferable upper limit is 10 kPa. When the degree of vacuum in the reduced-pressure atmosphere is within this range, the one base material and the other base material are not spent for a long time to achieve a vacuum state due to the airtightness of the vacuum device and the ability of the vacuum pump. Bubbles in the sealing agent for organic EL display elements of the present invention when the material is bonded can be more efficiently removed.

According to the present invention, there is provided an encapsulant for an organic EL display element that can be easily applied by an ink jet method, can obtain a cured product that is excellent in low outgassing properties and excellent in bending resistance. it can.

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

(Examples 1-5, Comparative Examples 1-4)
In accordance with the blending ratio described in Table 1, each material was uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring mixer (“Primix Corporation,“ Homodisper L type ”). To 5 and Comparative Examples 1 to 4 were prepared as sealants for organic EL display elements.
About each organic electroluminescent display element sealing agent obtained by the Example and the comparative example, it measured on 25 degreeC and 100 rpm conditions using an E-type viscosity meter (the Toki Sangyo company make, "VISCOMETER TV-22"). Table 1 shows the measured viscosity and the surface tension measured at 25 ° C. with a dynamic wettability tester (Reska, “WET-6100 type”).
Moreover, the film was produced by irradiating 3000 mJ / cm < ² > of ultraviolet rays with a wavelength of 365 nm with respect to each sealing agent for organic EL display elements obtained by the Example and the comparative example with the LED lamp. About the obtained film (thickness 1 mm), using a tensile tester (product made from INSTRON, "5582 type") and an orthogonal strain gauge (product made from Kyowa Dengyo Co., Ltd., "KFG-5-120-D16-23"), 25 A tensile test was performed at a constant speed under the conditions of ° C., 50% RH, and the distance between chucks of 100 mm, and Poisson's ratio and Young's modulus were obtained. Table 1 shows the measurement results of Poisson's ratio and Young's modulus.

<Evaluation>
The following evaluation was performed about each sealing agent for organic EL display elements obtained by the Example and the comparative example. The results are shown in Table 1.
In each evaluation of ink jet discharge property, wettability and organic EL display element reliability, IJH-30 (manufactured by IJT) was used as an ink jet coating head, and ink jet coating was performed without heating. (Head temperature 25 ° C.).

(1) Inkjet applicability (1-1) Inkjet ejection properties Each of the organic EL display element sealants obtained in the Examples and Comparative Examples was used with an inkjet ejection device (“NanoPrinter500” manufactured by Microjet Co., Ltd.). The solution was applied on alkali-washed non-alkali glass (“AN100” manufactured by Asahi Glass Co., Ltd.) with a droplet volume of 30 picoliters. The case where the droplets were normally ejected from the ink jet nozzle and landed on the substrate was evaluated as “◯”, and the case where the droplet was not ejected normally was evaluated as “X”, and the ink jet ejectability was evaluated.

(1-2) Wetting and spreading property Each of the organic EL display element sealants obtained in Examples 1 to 5 and Comparative Examples 3 and 4 was used with an inkjet discharge device (“NanoPrinter500” manufactured by MicroJet). Then, 1000 drops were applied at a speed of 5 m / second at a pitch of 500 μm on alkali-washed non-alkali glass (“AN100” manufactured by Asahi Glass Co., Ltd.) with a drop volume of 30 picoliters. The diameter of the droplet on the alkali-free glass 10 minutes after the coating was measured. 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 “ “Δ”, the case where the diameter of the droplet was less than 50 μm was evaluated as “×”, and the wetting and spreading property was evaluated.

(2) Low outgassing performance Outgas generated during heating of the cured products of the sealants for organic EL display elements obtained in Examples 1 to 5 and Comparative Examples 3 and 4 is gas chromatograph by headspace method (manufactured by JEOL). , “JMS-Q1050GC”). 100 mg of each organic EL display element sealant was applied to a thickness of 300 μm with an applicator. Next, after curing the sealant by irradiating UV light having a wavelength of 365 nm with an LED lamp at 3000 mJ / cm ² , the cured sealant was put in a headspace vial, and the vial was sealed, For 30 minutes, and the generated gas was measured by the headspace method.
The case where the generated gas was less than 300 ppm was evaluated as “◯”, the case where it was 300 ppm or more and less than 500 ppm as “Δ”, and the case where it was 500 ppm or more as “x”, and the low outgassing property was evaluated.

(3) Bending resistance (mandrel test)
About the hardened | cured material of each sealing agent for organic EL display elements obtained in Examples 1-5 and Comparative Examples 3 and 4, it was made flexible as follows by a cylindrical mandrel test having a specified radius of curvature. It was measured.
First, each organic EL display element sealant was dropped onto a polyethylene naphthalate substrate having a thickness of 100 μm, applied to a thickness of 10 μm with a spin coater, and then irradiated with UV light having a wavelength of 365 nm of 3000 mJ / A test piece was obtained after cm ² irradiation.
Next, a cylindrical mandrel test was performed on the obtained test piece by a method based on JIS K5600-5-1. For the mandrel test, a cylindrical mandrel with a diameter of 10 mm and a diameter of 4 mm was used. The mandrel with the larger diameter was tested in order from the mandrel with the smaller diameter, and the diameter of the mandrel where cracks and peeling occurred on the test piece for the first time was determined. confirmed. The case where cracks and peeling did not occur even with a mandrel having a diameter of 4 mm was “◯”, and the case where cracks were not peeled off with a mandrel having a diameter of 10 mm was “Δ”. When the mandrel was cracked or peeled off, the bending resistance (mandrel test) was evaluated as “x”.

(4) Reliability of organic EL display element (4-1) Preparation of a substrate on which a laminate having an organic light emitting material layer is disposed An ITO electrode is placed on a glass substrate (length 25 mm, width 25 mm, thickness 0.7 mm). A substrate having a thickness of 1000 mm was used as a substrate. The substrate was ultrasonically washed with acetone, an aqueous alkali solution, ion-exchanged water, and isopropyl alcohol for 15 minutes each, then washed with boiled isopropyl alcohol for 10 minutes, and further UV-ozone cleaner (manufactured by Nippon Laser Electronics Co., Ltd., The last treatment was performed with “NL-UV253”).
Next, this substrate is fixed to a substrate folder of a vacuum evaporation apparatus, and 200 mg of N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (α-NPD) is put into another unbaked crucible in the unglazed crucible. 200 mg of tris (8-quinolinolato) aluminum (Alq ₃ ) was put in the crucible, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. Thereafter, the crucible containing α-NPD was heated and α-NPD was deposited on the substrate at a deposition rate of 15 Å / s to form a 600 正 孔 hole transport layer. Next, the crucible containing Alq ₃ was heated to form an organic light emitting material layer having a thickness of 600 で at a deposition rate of 15 Å / s. Thereafter, the substrate on which the hole transport layer and the organic light emitting material layer are formed is transferred to another vacuum vapor deposition apparatus, and 200 mg of lithium fluoride is added to a tungsten resistance heating boat in the vacuum vapor deposition apparatus, and an aluminum wire is added to another tungsten boat. 1.0 g was added. Then, after reducing the pressure in the vapor deposition unit of the vacuum vapor deposition apparatus to 2 × 10 ⁻⁴ Pa and depositing 5 μm of lithium fluoride at a deposition rate of 0.2 kg / s, deposit 1000 μm of aluminum at a rate of 20 kg / s. did. The inside of the vapor deposition unit 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.

(4-2) Coating with Inorganic Material Film 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 inorganic by plasma CVD method. A material film A was formed.
In the plasma CVD method, SiH ₄ gas and nitrogen gas are used as source gases, the flow rates of each are SiH ₄ gas 10 sccm, nitrogen gas 200 sccm, RF power 10 W (frequency 2.45 GHz), chamber temperature 100 ° C., chamber The test was performed under the condition that the internal pressure was 0.9 Torr.
The formed inorganic material film A had a thickness of about 1 μm.

(4-3) Formation of Resin Protective Film Each of the organic EL display element sealants obtained in Examples 1 to 5 and Comparative Examples 3 and 4 was applied to the obtained substrate using an inkjet discharge device (Microjet Corporation). A pattern was applied to the substrate using “NanoPrinter500”).
Thereafter, an ultraviolet ray having a wavelength of 365 nm was irradiated with 3000 mJ / cm ² using an LED lamp to cure the organic EL display element sealant to form a resin protective film.

(4-4) After forming the coating resin protective film with the inorganic material film B, 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 formed by plasma CVD. Film B was formed to obtain an organic EL display element.
The plasma CVD method was performed under the same conditions as in the above “(4-2) Coating with inorganic material film A”.
The formed inorganic material film B had a thickness of about 1 μm.

(4-5) Light-Emitting State of Organic EL Display Element The obtained organic EL display element is exposed for 100 hours in an environment of a temperature of 85 ° C. and a humidity of 85%, and then a voltage of 3 V is applied to the organic EL display element. The light emission state (the presence or absence of dark spots and pixel periphery quenching) was visually observed. “○” when there is no dark spot or peripheral quenching, and “△” when there is no dark spot or peripheral quenching, but “△” when there is a slight decrease in brightness, when dark spot or peripheral quenching is observed The reliability of the organic EL display element was evaluated with “×”.

In order to confirm the effect of the viscosity of the sealing agent for organic EL display elements on the inkjet applicability in the non-heated inkjet method and the heated inkjet method, the following experiment was performed. The results are shown in Table 2.

(Experimental example 1)
In accordance with the blending ratio described in Table 2, each material was uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring mixer (manufactured by Primics Co., Ltd., “Homodisper L type”). The sealing agent for organic EL display elements was produced by performing the spin-drying | dehydration process exposed to a 0.1 MPa environment for 30 minutes.
About the obtained sealing agent for organic EL display elements, the viscosity measured on 25 degreeC and 100 rpm conditions using the E-type viscosity meter (the Toki Sangyo company make, "VISCOMETER TV-22"), and 25 degreeC The surface tension was measured with a dynamic wettability tester (“WET-6100” manufactured by Reska Co., Ltd.).
Moreover, with respect to the obtained sealing agent for organic EL display elements, the film was produced by irradiating 3000 mJ / cm < ² > of ultraviolet rays with a wavelength of 365 nm with an LED lamp. About the obtained film (thickness 1 mm), using a tensile tester (product made from INSTRON, "5582 type") and an orthogonal strain gauge (product made from Kyowa Dengyo Co., Ltd., "KFG-5-120-D16-23"), 25 A tensile test was performed at a constant speed under the conditions of ° C., 50% RH, and the distance between chucks of 100 mm, and Poisson's ratio and Young's modulus were obtained.
The obtained sealant for organic EL display element was alkali-washed with an ink-jet discharge device (“NanoPrinter500” manufactured by Microjet Co., Ltd.) with a droplet volume of 30 picoliters (manufactured by Asahi Glass Co., Ltd.). , “AN100”). The ink jet discharge performance was evaluated by assuming that “◯” indicates that the liquid droplets were normally discharged from the ink jet nozzle and landed on the substrate, and “X” indicates that the liquid droplets were not normally discharged. In addition, IJH-30 (manufactured by IJT) was used as an inkjet coating head, and inkjet coating was performed without heating (head temperature 25 ° C.).

(Experimental example 2)
The same sealing agent for organic EL display elements as that prepared in Experimental Example 1 was prepared.
Inkjet ejection properties were 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 an encapsulant for an organic EL display element that can be easily applied by an ink jet method, can obtain a cured product that is excellent in low outgassing properties and excellent in bending resistance. it can.

Claims (3)

Containing a polymerizable compound and a polymerization initiator,
The viscosity at 25 ° C. is 5 to 50 mPa · s, the surface tension at 25 ° C. is 15 to 35 mN / m, and the Poisson's ratio at 25 ° C. of the cured product is 0.28 to 0.40. Sealant for organic EL display elements. The Young's modulus at 25 degreeC of hardened | cured material is 1500-5000 Mpa, The sealing agent for organic EL display elements of Claim 1 characterized by the above-mentioned . 3. The encapsulant for organic EL display elements according to claim 1 , wherein the polymerizable compound is a (meth) acrylic compound.