JP7007272B2 - Encapsulant for organic EL display elements - Google Patents

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 is a sealing agent for an organic EL display element containing a polymerizable compound, wherein the polymerizable compound reacts with a high boiling point polymerizable compound having a boiling point of 300 ° C. or higher and the above high boiling point polymerizable compound. The low-boiling-boiling polymerizable compound having a possible reactive functional group and having a boiling point of less than 300 ° C. is a cyclic ether compound, a (meth) acrylic compound, and hydrosilylation. At least one selected from the group consisting of reactive compounds, the content of the low boiling point polymerizable compound in 100 parts by weight of the polymerizable compound is 1 part by weight or more and 20 parts by weight or less, and the thickness is 10 μm. A sealant for an organic EL display element having a haze of 1.0% or less of a cured product.
The present invention 2 is a sealing agent for an organic EL display element containing a polymerizable compound, wherein the polymerizable compound reacts with a high boiling point polymerizable compound having a boiling point of 300 ° C. or higher and the above high boiling point polymerizable compound. It contains a low boiling point polymerizable compound having a possible reactive functional group and having a boiling point of less than 300 ° C., and the content of the low boiling point polymerizable compound in 100 parts by weight of the above polymerizable compound is 1 part by weight. It is 20 parts by weight or less, and the amount of outgas generated in the cured product obtained by pre-coating with a thickness of 10 μm and then irradiating with ultraviolet rays of 395 nm at 1000 mJ / cm ² is less than 1000 ppm, and the haze of the cured product having a thickness of 10 μm. Is a sealing agent for an organic EL display element having a content of 1.0% or less.
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 deteriorate the inkjet ejection property and ejection stability due to volatilization, and generate outgas. Therefore, the present inventors seal the organic EL display element without using a polymerizable compound having a low boiling point as the polymerizable compound. We considered making an agent. However, the encapsulant for an organic EL display element produced without using a polymerizable compound having a low boiling point has a problem that the wettability and spreadability are inferior. Therefore, the present inventors have studied the blending of a specific high boiling point polymerizable compound and a specific low boiling point polymerizable compound so that the content ratio is within a specific range. As a result, it is possible to obtain a sealing agent for an organic EL display element that can be easily applied by an inkjet method and can be used for manufacturing an organic EL display element having excellent low outgassing properties and excellent reliability. And came to complete the present invention.

The encapsulant for an organic EL display element of the present invention contains a polymerizable compound.
The polymerizable compound has a high boiling point polymerizable compound having a boiling point of 300 ° C. or higher (hereinafter, also simply referred to as “high boiling point polymerizable compound”) and a reactive functional group capable of reacting with the high boiling point polymerizable compound. It also contains a low boiling point polymerizable compound having a boiling point of less than 300 ° C. (hereinafter, also simply referred to as “low boiling point polymerizable compound”). By using the high boiling point polymerizable compound and the low boiling point polymerizable compound in combination so as to have the contents described later, the encapsulant for an organic EL display element of the present invention has ink jet ejection property and ejection stability. In addition, it has excellent wettability and spreadability.
In the present specification, the above-mentioned "boiling point" means a boiling point under 1 atm. Further, for a compound having a high boiling point that cannot be directly measured, it means a value calculated by a boiling point conversion table using the boiling point under reduced pressure.

The high boiling point polymerizable compound has a boiling point of 300 ° C. or higher. As described above, the present invention is used by using the high boiling point polymerizable compound having a boiling point of 300 ° C. or higher and the low boiling point polymerizable compound having a boiling point of less than 300 ° C. in combination so as to have a content described later. The encapsulant for an organic EL display element is excellent in inkjet ejection property, ejection stability, and wet spreading property.

The high boiling point polymerizable compound is preferably at least one selected from the group consisting of a cyclic ether compound, a (meth) acrylic compound, and a hydrosilylation-reactive compound from the viewpoint of low outgassing property.
In addition, in this specification, the said "(meth) acrylic" means acrylic or methacrylic. Further, the above-mentioned "hydrosilylation-reactive compound" means a compound having a -SiH group or a compound having a carbon-carbon double bond capable of reacting with the -SiH group.

Specific examples of the high boiling point polymerizable compound include alkenyl group-containing organopolysiloxane, 3', 4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 1,4-butanediol diglycidyl ether. , Bisphenol F type epoxy resin, 2-ethylhexyloxetane, bis ((3-ethyloxetane-3-yl) methyl) ether, dicyclopentenyloxyethyl acrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate and the like. ..
Examples of the alkenyl group-containing organopolysiloxane include vinyl-terminated polydimethylsiloxane, vinyl-terminated polymethylphenylsiloxane, vinyl-terminated polydiphenylsiloxane, and the like.
As the high boiling point polymerizable compound, bis ((3-ethyloxetane-3-yl) methyl) ether is preferable.

The alkenyl group-containing organopolysiloxane can be produced by subjecting a disiloxane containing a terminal alkenyl group and a cyclic organopolysiloxane to an equilibrium reaction in the presence of an alkaline catalyst.
The cyclic organopolysiloxane may be a compound containing an alkenyl group in the side chain such as 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane.

The low boiling point polymerizable compound has a boiling point of less than 300 ° C. As described above, the present invention is used by using the high boiling point polymerizable compound having a boiling point of 300 ° C. or higher and the low boiling point polymerizable compound having a boiling point of less than 300 ° C. in combination so as to have a content described later. The encapsulant for an organic EL display element is excellent in inkjet ejection property, ejection stability, and wet spreading property. The preferred upper limit of the boiling point of the low boiling point polymerizable compound is 290 ° C.
Further, from the viewpoint of low outgassing property and the like, the preferable lower limit of the boiling point of the low boiling point polymerizable compound is 150 ° C., the more preferable lower limit is 200 ° C., and the more preferable lower limit is 240 ° C.

The low boiling point polymerizable compound has a reactive functional group capable of reacting with the high boiling point polymerizable compound. The reactive functional group depends on the type of the high boiling point polymerizable compound, and is, for example, a carbon-carbon double bond capable of reacting with an epoxy group, an oxetanyl group, a (meth) acryloyl group, a -SiH group, or a -SiH group. Examples include groups containing.
In addition, in this specification, the said "(meth) acryloyl" means acryloyl or methacryloyl.

In the encapsulant for an organic EL display element of the present invention 1, the low boiling point polymerizable compound is at least one selected from the group consisting of a cyclic ether compound, a (meth) acrylic compound, and a hydrosilylation-reactive compound. be. A sealing agent for an organic EL display element obtained by the above-mentioned low boiling point polymerizable compound being at least one selected from the group consisting of a cyclic ether compound, a (meth) acrylic compound, and a hydrosilylation-reactive compound. Is excellent in low outgassing property.

In the encapsulant for an organic EL display element of the present invention 2, the low boiling point polymerizable compound is at least one selected from the group consisting of a cyclic ether compound, a (meth) acrylic compound, and a hydrosilylation-reactive compound. It is preferable to have. A sealing agent for an organic EL display element obtained by the above-mentioned low boiling point polymerizable compound being at least one selected from the group consisting of a cyclic ether compound, a (meth) acrylic compound, and a hydrosilylation-reactive compound. It becomes easy to set the amount of outgas generated in the cured product in the range described later.

Specific examples of the low boiling point polymerizable compound include 1,7-octadiendiepoxide (boiling point 243 ° C.), neopentyl glycol diglycidyl ether (boiling point 273 ° C.), and ethylene glycol diglycidyl ether (boiling point 269 ° C.). ), Isobornyl acrylate (boiling point 250 ° C), 1,6-hexanediol diacrylate (boiling point 295 ° C), 3-ethyl-3-hydroxymethyloxetane (boiling point 298 ° C), 3-ethyl-3-oxetane methanol (boiling point 298 ° C) Boiling point 241 ° C.), 3-allyloxyoxetane (boiling point 146 ° C.), 1,3-butadienediepoxide (boiling point 153 ° C.), methylhydrogenpolysiloxane (boiling point 142 ° C.) and the like. Among them, 1,7-octadiene epoxide, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, isobornyl acrylate, 1,6-hexanediol diacrylate, 3-ethyl-3-hydroxymethyloxetane, and , 3-Ethyl-3-oxetane At least one selected from the group consisting of methanol is preferable.

The lower limit of the content of the low boiling point polymerizable compound in 100 parts by weight of the polymerizable compound is 1 part by weight, and the upper limit is 20 parts by weight. When the content of the low boiling point polymerizable compound is in this range, the encapsulant for an organic EL display element of the present invention is excellent in inkjet ejection property, ejection stability, and wettability. The preferable lower limit of the content of the low boiling point polymerizable compound is 5 parts by weight, and the preferable upper limit is 10 parts by weight.

When the cyclic ether compound or the (meth) acrylic compound is used as the polymerizable compound, the encapsulant for an organic EL display element of the present invention preferably 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.

As the anionic moiety of the above-mentioned ionic photoacid generation type photocationic polymerization initiator, for example, the anionic moiety is BF _4- ^, PF _6- ^, SbF _6- , or (BX ₄ ^{)- (} where X is at least (Representing a phenyl group substituted with two or more fluorine or trifluoromethyl groups) 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- (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, triarylsulfonium tetrakis (pentafluorophenyl) borate, bis (4- (di (4- (2-hydroxyethoxy)) phenyl) Sulfonio) phenyl) sulfide bishexafluorophosphate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl) sulfide bishexafluoroantimonate, bis (4- (di (4- (4- (2-hydroxyethoxy))) 2-Hydroxyethoxy)) phenylsulfonio) phenyl) sulfide bistetrafluoroborate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl) sulfide tetrakis (pentafluorophenyl) borate, tris (4- (4-Acetylphenyl) thiophenyl) sulfonium tetrakis (pentafluorophenyl) borate and the like can be mentioned.

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, phenol sulfonic acid ester, diazonaphthoquinone, N-hydroxyimide sulfonate and the like.

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

In the above thermal cationic polymerization initiator, the anionic 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.

Examples of commercially available thermal cationic polymerization initiators include thermal cationic polymerization initiators manufactured by Sanshin Chemical Industry Co., Ltd., thermal cationic polymerization initiators manufactured by King Industries, and the like.
Examples of the thermal cationic polymerization initiator manufactured by Sanshin Chemical Industry Co., Ltd. include Sun Aid SI-60, Sun Aid SI-80, Sun Aid SI-B3, Sun Aid SI-B3A, and Sun Aid SI-B4.
Examples of the thermal cationic polymerization initiator manufactured by King Industries include CXC1612, CXC1821 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, IRGACURE OXE01, IRGACURE 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 of which are Fujifilm Wako Pure Chemical Industries, Ltd.). Made) and the like.

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, 2,2-dimethoxy-1,2-diphenylethane-1-one, benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'. -Bis (dimethylamino) benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide and the like can be mentioned.
Examples of the thioxanthone compound include 2,4-diethylthioxanthone 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, the absorption can be not excessively increased and the sensitizer can be cured to a deep part. 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.

When the hydrosilylation-reactive compound is used as the polymerizable compound, the encapsulant for an organic EL display element of the present invention preferably contains a hydrosilylation reaction catalyst.

Examples of the hydrosilylation reaction catalyst include (methylcyclopentadienyl) trimethyl platinum, bis (2,4-pentanedionate) platinum (II) and the like. Of these, (methylcyclopentadienyl) trimethyl platinum is preferable.

The content of the hydrosilylation reaction catalyst is preferably 0.0005 parts by weight and a preferable upper limit of 0.010 parts by weight with respect to 100 parts by weight of the polymerizable compound. When the content of the hydrosilylation reaction catalyst is 0.0005 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 hydrosilylation reaction catalyst is 0.010 part by weight or less, the curing reaction of the obtained sealant for an organic EL display element does not become too fast, and the workability is improved, so that the cured product is further improved. It can be uniform. The more preferable lower limit of the content of the hydrosilylation reaction catalyst is 0.001 part by weight, and the more preferable upper limit is 0.002 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 coupling agents 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 sealant for an organic EL display element of the present invention has a preferable lower limit of viscosity at 25 ° C. of 3 mPa · s and a preferred upper limit of 20 mPa · s. When the viscosity is in this range, the inkjet ejection property, ejection stability, and wettability and spreading property are improved. The more preferable lower limit of the viscosity is 5 mPa · s, and the more preferable upper limit is 15 mPa · s.
In the present specification, the viscosity means a value measured under the condition of 100 rpm using an E-type viscometer.

In the encapsulant for an organic EL display element of the present invention, the preferable lower limit of the surface tension at 25 ° C. is 15 mN / m, and the preferable upper limit is 35 mN / m. When the surface tension is in this range, the inkjet ejection property, ejection stability, and wettability and spreading property are improved. 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.
In addition, in this specification, the said surface tension means the value measured by the Wilhelmy method by the dynamic wettability tester.

The sealant for an organic EL display element of the present invention has an upper limit of haze of a cured product having a thickness of 10 μm of 1.0%. When the haze is 1.0% or less, the obtained organic EL display element has excellent optical characteristics. The preferred upper limit of the haze is 0.5%, and the more preferable upper limit is 0.3%. The lower the haze, the better, and there is no particular preferable lower limit, but the haze is substantially 0.01% or more.
Further, in the sealant for an organic EL display element of the present invention, the preferable lower limit of the total light transmittance of light at a wavelength of 380 to 800 nm of the cured product 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 haze value can be set within a desired range by adjusting the types and amounts of the high boiling point polymerizable compound, the low boiling point polymerizable compound, the polymerization initiator, and the sensitizer. In particular, by considering the compatibility between the high boiling point polymerizable compound and the low boiling point polymerizable compound and adjusting the combination of the types and the blending amount, it becomes easy to keep the content within a desired range. As a result, it is possible to obtain a sealing agent for an organic EL display element, which has better optical properties than a composition containing a high boiling point polymerizable compound and a low boiling point polymerizable compound.
The haze and the total light transmittance can be measured using, for example, a spectroscope such as AUTOMATIC HAZE METER MODEL TC-III DPK (manufactured by Tokyo Denshoku Co., Ltd.). Further, the cured product used for measuring the haze and the total light transmittance, and the moisture permeability and the water content described later, is irradiated with ultraviolet rays having a wavelength of 395 nm at 1000 mJ / cm ² using, for example, a light source such as an LED lamp. Can be obtained by

The encapsulant for an organic EL display element of the present invention 1 is preferably coated with a thickness of 10 μm in advance and then irradiated with ultraviolet rays of 395 nm at 1000 mJ / cm ² to generate an outgas amount of less than 1000 ppm. .. When the amount of outgas generated is less than 1000 ppm, the obtained organic EL display element becomes more reliable. The more preferable upper limit of the amount of outgas generated is 500 ppm, and the more preferable upper limit is 100 ppm.
The smaller the amount of outgas generated, the better, and there is no particular preferable lower limit, but the amount is substantially 5 ppm or more.
The amount of outgas generated can be measured using a gas chromatograph mass spectrometer (for example, JMS-Q1050 (manufactured by JEOL Ltd.)).

The encapsulant for an organic EL display element of the present invention 2 has an outgas generation amount of less than 1000 ppm obtained by irradiating the sealant for an organic EL display element with a thickness of 10 μm in advance and then irradiating with ultraviolet rays of 395 nm at 1000 mJ / cm ² . When the amount of outgas generated is less than 1000 ppm, the obtained organic EL display element becomes excellent in reliability. The preferable upper limit of the amount of outgas generated is 500 ppm, and the more preferable upper limit is 100 ppm.
The smaller the amount of outgas generated, the better, and there is no particular preferable lower limit, but the amount is substantially 5 ppm or more.

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 the deterioration of the organic light emitting material layer due to the moisture in the cured product becomes excellent, and the obtained organic EL display element becomes more excellent in reliability.

The encapsulant for an organic EL display element of the present invention preferably 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. 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 encapsulant for an organic EL display element of the present invention is preferably 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 sealing agent for an organic EL display element of the present invention is cured by light irradiation, the sealing agent for an organic EL display element of the present invention has a wavelength of 300 nm or more and 400 nm or less and 300 mJ / cm ² or more and 3000 mJ / cm ² or less. It can be suitably cured by irradiating it with a total amount of light.

Examples of the light source used for the above light irradiation include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an excima laser, a chemical lamp, a black light lamp, a microwave pumped mercury lamp, a metal halide lamp, a sodium lamp, a halogen lamp, and a xenon. Examples include lamps, LED lamps, fluorescent lamps, sunlight, and electron beam irradiators. 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 sealant 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. It is preferable that the sealant for an element has a pot life of 1 minute or more from the time when it is irradiated with light and / or heated 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 8, Comparative Examples 1 to 7)
According to the compounding ratios shown in Tables 1 to 3, each material was uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring / mixing machine (“Homodisper L type” manufactured by Primix Corporation). Sealants for organic EL display elements of Examples 1 to 8 and Comparative Examples 1 to 7 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. Tables 1 to 3 show the viscosity and the surface tension measured by a dynamic wettability tester (“WET-6100 type” manufactured by Resca) at 25 ° C.
Further, after applying the sealant for each organic EL display element obtained in Examples and Comparative Examples to a glass substrate in advance with a thickness of 10 μm, UV-LED is used to irradiate with ultraviolet rays of 395 nm at 1000 mJ / cm ² . Obtained a cured product. The obtained cured product was weighed and sealed in a vial in an amount of 20 mg. This vial was heated at 100 ° C. for 30 minutes, and the vaporized component in the vial was measured as the amount of outgas generated using a gas chromatograph mass spectrometer (“JMS-Q1050” manufactured by JEOL Ltd.). The results are shown in Tables 1 to 3.
Further, after applying the sealing agent for each organic EL display element obtained in Examples and Comparative Examples on a glass substrate, ultraviolet rays of 395 nm were irradiated at 1000 mJ / cm ² using a UV-LED to obtain a thickness of 10 μm. A cured product was obtained. For the obtained cured product, the haze and the total light transmittance of light at a wavelength of 380 to 800 nm were measured using a spectroscope. As the above spectroscope, AUTOMATIC HAZE METER MODEL TC-III DPK (manufactured by Tokyo Denshoku Co., Ltd.) was used.
It was confirmed that the boiling point of "Selokiside 2021P" and two kinds of "alkenyl group-containing organopolysiloxane" in the table was 300 ° C. or higher at 1 atm, but the boiling point could be measured accurately even under reduced pressure. Since there was no specific value of boiling point, it was set to "300 ° C or higher".

<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 Tables 1 to 3.

(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.). "○" indicates that there is no ejection defect and the ejection is clean, "△" indicates that the ejection defect is less than 20%, and "×" indicates that the ejection defect occurs at 20% or more. The inkjet ejection property was evaluated.

(1-2) Discharge Stability 80 picolitres of the sealant for each organic EL display element obtained in Examples and Comparative Examples are used with an inkjet discharge device (“NanoPrinter500” manufactured by Microjet Co., Ltd.). In terms of the amount of drops, 1000 drops were applied to non-alkali glass (manufactured by Asahi Glass Co., Ltd., "AN100") washed with alkali at a rate of 5 m / sec at a pitch of 500 μm. After the coating, the mixture was left at 25 ° C. for 10 minutes, the coating was performed 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 1 or more and less than 20, and droplets that could not be applied. When the number of the particles was 20 or more, the discharge stability was evaluated as “x”.

(1-3) Wetting and spreading property 30 picolitres of the sealant for each organic EL display element obtained in Examples and Comparative Examples are used with an inkjet ejection device (“NanoPrinter500” manufactured by Microjet Co., Ltd.). In terms of the amount of drops, 1000 drops were applied on non-alkali glass (manufactured by Asahi Glass Co., Ltd., "AN100") washed with alkali at a rate of 5 m / sec at a pitch of 500 μm. After the coating, the mixture was left at 25 ° C. for 10 minutes, and the diameter of the droplets on the non-alkali glass was measured.
When the diameter of the droplet is 150 μm or more, it is regarded as “○”, when the diameter of the droplet is 50 μm or more and less than 150 μm, it is regarded as “Δ”, and when the diameter of the droplet is less than 50 μm, it is regarded as “×”. Wet spreadability was evaluated.

(2) Reliability of organic EL display element (2-1) 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 substrate having a thickness of 1000 Å was prepared. The substrate is ultrasonically washed with acetone, an alkaline aqueous solution, ion-exchanged water, and isopropyl alcohol for 15 minutes each, then washed with boiled 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.

(2-2) Covering with Inorganic Material Membrane A A mask having an opening of 13 mm × 13 mm is installed so as to cover the entire laminate on which the obtained laminate is arranged, and the plasma CVD method is used to invert the substrate. 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.

(2-3) Formation of Resin Protective Film For the obtained substrate, the sealant for each organic EL display element obtained in Examples and Comparative Examples was applied to an inkjet ejection device (“NanoPrinter500” manufactured by Microjet Co., Ltd.). The pattern was applied to the substrate using.
Then, using an LED lamp, ultraviolet rays having a wavelength of 395 nm were irradiated at 1000 mJ / cm ² to cure the sealant for the organic EL display element to form a resin protective film.

(2-4) 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 "(2-2) Coating with inorganic material film A".
The thickness of the formed inorganic material film B was about 1 μm.

(2-5) 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 reliability of the organic EL display element.

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 (6)

A sealing agent for organic EL display elements containing a polymerizable compound.
The polymerizable compound has a high boiling point polymerizable compound having a boiling point of 300 ° C. or higher and a low boiling point polymerizable compound having a reactive functional group capable of reacting with the high boiling point polymerizable compound and having a boiling point of less than 300 ° C. And contains,
The low boiling point polymerizable compound is at least one selected from the group consisting of a cyclic ether compound, a (meth) acrylic compound, and a hydrosilylation-reactive compound.
The content of the low boiling point polymerizable compound in 100 parts by weight of the polymerizable compound is 1 part by weight or more and 20 parts by weight or less.
The viscosity at 25 ° C. is 3 mPa · s or more and 20 mPa · s or less.
The solvent content is 0.05% by weight or less,
A sealing agent for an organic EL display element, characterized in that the haze of a cured product having a thickness of 10 μm is 1.0% or less. A sealing agent for organic EL display elements containing a polymerizable compound.
The polymerizable compound has a high boiling point polymerizable compound having a boiling point of 300 ° C. or higher and a low boiling point polymerizable compound having a reactive functional group capable of reacting with the high boiling point polymerizable compound and having a boiling point of less than 300 ° C. And contains,
The content of the low boiling point polymerizable compound in 100 parts by weight of the polymerizable compound is 1 part by weight or more and 20 parts by weight or less.
The viscosity at 25 ° C. is 3 mPa · s or more and 20 mPa · s or less.
The solvent content is 0.05% by weight or less,
The amount of outgas generated in the cured product obtained by pre-applying with a thickness of 10 μm and then irradiating with ultraviolet rays of 395 nm at 1000 mJ / cm ² is less than 1000 ppm.
A sealing agent for an organic EL display element, characterized in that the haze of a cured product having a thickness of 10 μm is 1.0% or less. The sealant for an organic EL display element according to claim 1 or 2, wherein the low boiling point polymerizable compound has a boiling point of 150 ° C. or higher. Low boiling point polymerizable compounds include 1,7-octadiene epoxide, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, isobornyl acrylate, 1,6-hexanediol diacrylate, 3-ethyl-3-hydroxy. The sealant for an organic EL display element according to claim 1, 2 or 3, wherein the sealant is at least one selected from the group consisting of methyl oxetane and 3-ethyl-3-oxetane methanol. The sealant for an organic EL display element according to claim 1, 2, 3 or 4 , wherein the surface tension at 25 ° C. is 15 mN / m or more and 35 mN / m or less. The sealing agent for an organic EL display element according to claim 1, 2, 3, 4 or 5 , which is used for coating by an inkjet method.