JP6966454B2 - In-plane encapsulant for organic EL display element and encapsulant set for organic EL display element - Google Patents

Description

The present invention relates to an in-plane encapsulant for an organic EL display element having excellent coatability, wet spreadability, and curability. The present invention also relates to a sealant set for an organic EL display element, which comprises a peripheral sealant and an in-plane sealant for the organic EL display element.

The organic electroluminescence display element (organic EL display element) has a thin film structure in which an organic light emitting material layer is sandwiched between a pair of electrodes facing each other. Electrons are injected into the organic light emitting material layer from one electrode and holes are injected from the other electrode, so that electrons and holes are combined in the organic light emitting material layer to perform self-luminous emission. Compared to a liquid crystal display element or the like that requires a backlight, it has the advantages of better visibility, thinner size, and low DC voltage drive.

However, such an organic EL display element has a problem that when the organic light emitting material layer or the electrode is exposed to the outside air, its light emitting characteristics are rapidly deteriorated and its life is shortened. Therefore, in order to improve the stability and durability of the organic EL display element, a sealing technology that shields the organic light emitting material layer and the electrode from the moisture and oxygen in the atmosphere is indispensable for the organic EL display element. There is.

Patent Document 1 includes an organic packing layer made of an in-plane sealing agent that coats and seals a laminate having an organic light emitting material layer, and a peripheral sealing agent containing a water absorbent. Disclosed is a method of sealing an organic EL display element by a configuration having a moisture absorbing seal layer covering the side surface of the organic EL display element. However, when the organic EL display element is sealed by the configuration using such an in-plane encapsulant and a peripheral encapsulant, an in-plane encapsulant having excellent coatability and wet spreadability is used. However, there are problems that sufficient curability may not be obtained and display defects may occur in the organic EL display element.

Japanese Unexamined Patent Publication No. 2014-67598

An object of the present invention is to provide an in-plane encapsulant for an organic EL display element having excellent coatability, wet spreadability, and curability. Another object of the present invention is to provide a sealant set for an organic EL display element, which comprises a peripheral sealant and an in-plane sealant for the organic EL display element.

The present invention is an in-plane sealant for an organic EL display element used by applying it to the inside of a peripheral sealant for an organic EL display element containing a water absorber, and comprises a curable resin and a cationic polymerization initiator. The curable resin contains a cycloalkene oxide-type alicyclic epoxy compound having a silicone skeleton, and uses an E-type viscosity meter in the entire in-plane sealant for an organic EL display element at 25 ° C. , An in-plane sealant for an organic EL display element having a viscosity of 50 mPa · s or more and 150 mPa · s or less measured under the condition of 20 rpm.
The present invention will be described in detail below.

The present inventor has found that the cause of insufficient curability of the in-plane sealant when the organic EL display element is sealed by the configuration using the in-plane sealant and the peripheral sealant is the peripheral seal. It was considered that the water absorber contained in the stopper was present in the water absorber, and the water absorber inhibited the curing of the in-plane encapsulant. Therefore, as a result of diligent studies by the present inventor, by using a compound having a specific structure as the curable resin used for the in-plane encapsulant, coatability, wet spreadability, and curability (particularly, a water absorber) can be obtained. It has been found that an in-plane encapsulant for an organic EL display element having excellent curability when used in combination with a contained peripheral encapsulant can be obtained, and the present invention has been completed. Further, by using the in-plane encapsulant for an organic EL display element of the present invention, it is possible to suppress the occurrence of display defects due to the in-plane encapsulant permeating into the laminate having the organic light emitting material layer, and the display performance can be suppressed. It is possible to obtain an excellent display element.

The in-plane encapsulant for an organic EL display element of the present invention contains a curable resin.
The curable resin contains a cycloalkene oxide-type alicyclic epoxy compound having a silicone skeleton. By containing the cycloalkene oxide type alicyclic epoxy compound having the above silicone skeleton, the in-plane encapsulant for an organic EL display element of the present invention has excellent curability and is dark in the obtained organic EL display element. It is possible to suppress display defects such as spots.

As the cycloalkene oxide-type alicyclic epoxy compound having the above silicone skeleton, the compound represented by the following formula (1) is preferable because it is excellent in wet spreadability and curability, and further, a low outgassing and organic light emitting material. The compound represented by the following formula (2) is more preferable because it is excellent in the effect of suppressing the penetration into the laminated body having a layer.

In the formula (1), n represents an integer of 0 or more and 10 or less.

The preferable lower limit of the content of the cycloalkene oxide-type alicyclic epoxy compound having the silicone skeleton in 100 parts by weight of the curable resin is 20 parts by weight, and the preferable upper limit is 70 parts by weight. When the content of the cycloalkene oxide-type alicyclic epoxy compound having the above silicone skeleton is 20 parts by weight or more, the obtained in-plane sealant for an organic EL display element has curability and the obtained organic EL. It is superior due to the effect of suppressing display defects of the display element. When the content of the cycloalkene oxide-type alicyclic epoxy compound having the silicone skeleton is 70 parts by weight or less, the obtained in-plane sealant for an organic EL display element becomes excellent in coatability. The more preferable lower limit of the content of the cycloalkene oxide type alicyclic epoxy compound having a silicone skeleton is 40 parts by weight, and the more preferable upper limit is 60 parts by weight.

The curable resin preferably contains another curable resin for the purpose of adjusting the viscosity of the obtained in-plane sealant for an organic EL display element.
Examples of the other curable resin include other epoxy compounds, oxetane compounds, vinyl ether compounds and the like.
Examples of the other epoxy compounds include compounds represented by the following formula (3), dicyclopentadiene dimethanol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and the like. Examples thereof include hydrogenated bisphenol F diglycidyl ether.
Examples of the oxetane compound include bis ((3-ethyloxetane-3-yl) methyl) ether, phenoxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, and 3-ethyl-3- (phenoxymethyl) oxetane. 3-Ethyl-3-((2-ethylhexyloxy) methyl) oxetane, 3-ethyl-3-((3- (triethoxysilyl) propoxy) methyl) oxetane, oxetanylsilsesquioxane, phenol novolac oxetane, 1, Examples thereof include 4-bis (((3-ethyl-3-oxetanyl) methoxy) methyl) benzene and the like.
Examples of the vinyl ether compound include benzyl vinyl ether, cyclohexanedimethanol monovinyl ether, dicyclopentadienvinyl ether, 1,4-butanediol divinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, and dipropylene glycol. Examples thereof include divinyl ether and tripropylene glycol divinyl ether.
Among them, the compound represented by the following formula (3) is preferable, and the compound represented by the following formula (4-1) and the compound represented by the following formula (4-2) are preferable from the viewpoint of curability and low outgassing property. Compounds are more preferred.

In the formula (3), R ^{1 to} R ¹⁸ are hydrocarbon groups which may contain a hydrogen atom, a halogen atom, an oxygen atom or a halogen atom, and may be the same or different from each other. May be good. X is a bond, an oxygen atom, an alkylene group having 1 to 5 carbon atoms, an oxycarbonyl group, an alkyleneoxycarbonyl group having 2 to 5 carbon atoms, or a secondary amino group.

The in-plane encapsulant for an organic EL display element of the present invention contains a cationic polymerization initiator.
Examples of the cationic polymerization initiator include a thermal cationic polymerization initiator that generates protonic acid or Lewis acid by heating, and a photocationic polymerization initiator that generates protonic acid or Lewis acid by light irradiation, and is an ionic acid generation type. It may be a non-ionic acid generating type.

As the thermal cationic polymerization _{^{initiator, BF 4 -, PF 6 -}} , SbF 6 -, or, _(BX 4) ^- (where the phenyl X is substituted with at least two or more fluorine or trifluoromethyl group A sulfonium salt, a phosphonium salt, a quaternary ammonium salt, a diazonium salt, or an iodonium salt having (representing a group) as a counter anion is preferable. Among them, the sulfonium salt having the above-mentioned counter anion is more preferable.

Examples of the sulfonium salt include triphenylsulfonium boron tetrafluoride, triphenylsulfonium hexafluoroantimon, triphenylsulfonium arsenide hexafluoride, tri (4-methoxyphenyl) sulfonium arsenide hexafluoride, and diphenyl (4-phenylthiophenyl). ) Sulfonium hexafluoride arsenic and the like.
Examples of the phosphonium salt include ethyltriphenylphosphonium hexafluoride antimony and tetrabutylphosphonium hexafluoride antimony.
Examples of the quaternary ammonium salt include dimethylphenyl (4-methoxybenzyl) ammonium hexafluorophosphate, dimethylphenyl (4-methoxybenzyl) ammonium hexafluoroantimonate, and dimethylphenyl (4-methoxybenzyl) ammonium tetrakis (penta). Fluorophenyl) borate, dimethylphenyl (4-methylbenzyl) ammonium hexafluorophosphate, dimethylphenyl (4-methylbenzyl) ammonium hexafluoroantimonate, dimethylphenyl (4-methylbenzyl) ammonium hexafluorotetrakis (pentafluorophenyl) bolate , Methylphenyldibenzylammonium, Methylphenyldibenzylammonate hexafluoroantimonate hexafluorophosphate, Methylphenyldibenzylammonium tetrakis (pentafluorophenyl) borate, phenyltribenzylammonium tetrakis (pentafluorophenyl) borate, dimethylphenyl (3, 4-dimethylbenzyl) ammonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl-N-benzylanilinium hexafluoride antimony, N, N-diethyl-N-benzylanilinium tetrafluoride boron, N, N- Examples thereof include dimethyl-N-benzylpyridinium hexafluoride antimony, N, N-diethyl-N-benzylpyridinium trifluoromethanesulfonic acid and the like.

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 CXC-1612, CXC-1738, CXC-1821 and the like.

The anionic portion of the ionic acid generation-type cationic photopolymerization initiator, for _{^{example, BF 4 -, PF 6 -}} , SbF 6 -, or, _(BX 4) ^- (where, X is at least two (Representing a phenyl group substituted with a fluorine or trifluoromethyl group) and the like.
Examples of the ionic photoacid generation type photocationic polymerization initiator include aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, aromatic ammonium salts, or (2,4) having the above anionic moiety. -Cyclopentadiene-1-yl) ((1-methylethyl) benzene) -Fe salt and the like can be mentioned.

Examples of the aromatic sulfonium salt include bis (4- (diphenylsulfonio) phenyl) sulfide bishexafluorophosphate, bis (4- (diphenylsulfonio) phenyl) sulfide bishexafluoroantimonate, and bis (4-( Diphenylsulfonio) phenyl) sulfide bistetrafluoroborate, bis (4- (diphenylsulfonio) phenyl) sulfide tetrakis (pentafluorophenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- ( Phenylthio) phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenylthio) phenylsulfonium tetrafluoroborate, diphenyl-4- (phenylthio) phenylsulfonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexa Fluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonate) phenyl) sulfide bishexafluorophosphate, Bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl) Sulfide bishexafluoroantimonate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl ) Sulfide bistetrafluoroborate, bis (4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl) sulfide tetrakis (pentafluorophenyl) borate 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, 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) borate and the like.

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.

Among the above photocationic polymerization initiators, examples of the nonionic acid generating type include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenol sulfonic acid ester, diazonaphthoquinone, N-hydroxyimide sulfonate and the like. Be done.

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 Chemical 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 IRGACURE290 and the like.
Examples of the photocationic polymerization initiator manufactured by Rhodia include PI2074 and the like.

Those described in both the thermal cationic polymerization initiator and the photocationic polymerization initiator can be used as the thermal cationic polymerization initiator and can also be used as the photocationic polymerization initiator.

Among the above-mentioned cationic polymerization initiators, a quaternary ammonium salt having a borate-based counter anion (hereinafter, also referred to as “borate-based quaternary ammonium salt”) is preferably used. Counter anion of the borate-based quaternary ammonium salt, BF ₄ ^- or (BX ₄₎ - ^(provided that, X is representative of at least two or more fluorine or trifluoromethyl-substituted phenyl) are Is preferable.

The content of the cationic polymerization initiator has a preferable lower limit of 0.05 parts by weight and a preferable upper limit of 10 parts by weight with respect to 100 parts by weight of the cationically polymerizable compound. When the content of the cationic polymerization initiator is in this range, the obtained in-plane sealant for an organic EL display element becomes more excellent in curability and storage stability. The more preferable lower limit of the content of the cationic polymerization initiator is 0.1 parts by weight, and the more preferable upper limit is 5 parts by weight.

The in-plane 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 photocationic polymerization initiator and further promoting the curing reaction of the in-plane encapsulant for an organic EL display element of the present invention.

Examples of the sensitizer include anthracene compounds, thioxanthone compounds, 2,2-dimethoxy-1,2-diphenylethane-1-one, benzophenone, 2,4-dichlorobenzophenone, and methyl o-benzoylbenzoate. Examples thereof include 4,4'-bis (dimethylamino) benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide and the like.
Examples of the anthracene-based compound include 9,10-dibutoxyanthracene and the like.
Examples of the thioxanthone-based compound include 2,4-diethylthioxanthone and the like.

The content of the sensitizer is preferably 0.05 parts by weight and a preferable upper limit of 3 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the sensitizer is 0.05 parts by weight or more, the sensitizing effect is more exhibited. When the content of the sensitizer is 3 parts by weight or less, light can be transmitted to a deep part without excessive absorption. The more preferable lower limit of the content of the sensitizer is 0.1 parts by weight, and the more preferable upper limit is 1 part by weight.

The in-plane encapsulant for an organic EL display element of the present invention may contain a thermosetting agent.
Examples of the thermosetting agent include hydrazide compounds, imidazole derivatives, acid anhydrides, dicyandiamides, guanidine derivatives, modified aliphatic polyamines, and addition products of various amines and epoxy resins.

Examples of the hydrazide compound include 1,3-bis (hydrazinocarboethyl) -5-isopropylhydrandine, sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide and the like.
Examples of the imidazole derivative include 1-cyanoethyl-2-phenylimidazole, N- (2- (2-methyl-1-imidazolyl) ethyl) urea, and 2,4-diamino-6- (2'-methylimidazole-). (1'))-Ethyl-s-triazine, N, N'-bis (2-methyl-1-imidazolylethyl) urea, N, N'-(2-methyl-1-imidazolylethyl) -adipamide, 2- Examples thereof include phenyl-4-methyl-5-hydroxymethylimidazole and 2-phenyl-4,5-dihydroxymethylimidazole.
Examples of the acid anhydride include tetrahydrophthalic anhydride, ethylene glycol bis (anhydrotrimeritate) and the like.
These thermosetting agents may be used alone or in combination of two or more.

Examples of commercially available thermosetting agents include a thermosetting agent manufactured by Japan Finechem Co., Ltd., a thermosetting agent manufactured by Otsuka Chemical Co., Ltd., and a thermosetting agent manufactured by Ajinomoto Fine Techno Co., Ltd.
Examples of the thermosetting agent manufactured by Japan Finechem Co., Ltd. include SDH and the like.
Examples of the thermosetting agent manufactured by Otsuka Chemical Co., Ltd. include ADH and the like.
Examples of the thermosetting agent manufactured by Ajinomoto Fine-Techno Co., Ltd. include Amicure VDH, Amicure VDH-J, and Amicure UDH.

The content of the thermosetting agent is preferably 0.5 parts by weight and a preferable upper limit of 30 parts by weight with respect to 100 parts by weight of the cationically polymerizable compound. When the content of the thermosetting agent is 0.5 parts by weight or more, the obtained in-plane encapsulant for an organic EL display element becomes more excellent in thermosetting. When the content of the thermosetting agent is 30 parts by weight or less, the obtained in-plane encapsulant for an organic EL display element becomes more excellent in storage stability. The more preferable lower limit of the content of the thermosetting agent is 1 part by weight, and the more preferable upper limit is 15 parts by weight.

The in-plane encapsulant for an organic EL display element of the present invention preferably contains a stabilizer. By containing the above stabilizer, the in-plane encapsulant for an organic EL display element of the present invention becomes more excellent in storage stability.

Examples of the stabilizer include amine compounds such as benzylamine and aminophenol type epoxy resins.

The content of the stabilizer is preferably 0.001 part by weight and a preferable upper limit of 2 parts by weight with respect to 100 parts by weight of the cationically polymerizable compound. When the content of the stabilizer is in this range, the obtained in-plane sealant for an organic EL display element becomes more excellent in storage stability while maintaining excellent curability. The more preferable lower limit of the content of the stabilizer is 0.005 parts by weight, and the more preferable upper limit is 1 part by weight.

The in-plane 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 in-plane encapsulant 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 cationically polymerizable compound. When the content of the silane coupling agent is within this range, the effect of improving the adhesiveness of the obtained in-plane encapsulant for an organic EL display element while preventing the bleed-out of the excess silane coupling agent is achieved. It will be 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 in-plane encapsulant for an organic EL display element of the present invention may 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 of the in-plane encapsulant for an organic EL display element of the present invention can be improved.
Examples of the surface modifier include a surfactant, a leveling agent and the like.

Examples of the surface modifier include silicone-based, acrylic-based, and fluorine-based agents.
Among the above surface modifiers, commercially available ones include, for example, a surface modifier manufactured by Big Chemie Japan, a surface modifier manufactured by Kusumoto Kasei Co., Ltd., and a surface modifier manufactured by AGC Seimi Chemical Co., Ltd. Can be mentioned.
Examples of the surface modifier manufactured by Big Chemie Japan Co., Ltd. include BYK-300, BYK-302, BYK-331 and the like.
Examples of the surface modifier manufactured by Kusumoto Kasei Co., Ltd. include UVX-272 and the like.
Examples of the surface modifier manufactured by AGC Seimi Chemical Co., Ltd. include Surflon S-611 and the like.

The in-plane encapsulant for an organic EL display element of the present invention was generated in the in-plane encapsulant for an organic EL display element in order to improve the durability of the element electrode without impairing the object of the present invention. It may contain a compound that reacts with an acid or an ion exchange resin.

Examples of the compound that reacts with the generated acid include substances that neutralize the acid, such as alkali metal carbonate or hydrogen carbonate, or alkaline earth metal carbonate or hydrogen carbonate. Specifically, for example, calcium carbonate, calcium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate and the like are used.

As the ion exchange resin, any of a cation exchange type, an anion exchange type, and a biion exchange type can be used, and in particular, a cation exchange type or a biion exchange type capable of adsorbing chloride ions can be used. Is preferable.

Further, the in-plane encapsulant for an organic EL display element of the present invention is a curing retarder, a reinforcing agent, a softener, a plasticizer, a viscosity modifier, and ultraviolet rays, as necessary, as long as the object of the present invention is not impaired. It may contain various known additives such as an absorbent and an antioxidant.

The in-plane encapsulant for an organic EL display element of the present invention preferably does not contain a solvent from the viewpoint of further suppressing the generation of outgas. The in-plane encapsulant for an organic EL display element of the present invention can be excellent in coatability even if it does not contain the solvent.

As a method for producing the in-plane 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 mixer is used to cure the material. Examples thereof include a method of mixing a resin, a cationic polymerization initiator, and an additive such as a stabilizer or a silane coupling agent to be added as needed.

In the in-plane encapsulant for an organic EL display element of the present invention, the lower limit of the total viscosity measured at 25 ° C. and 20 rpm using an E-type viscometer is 50 mPa · s, and the upper limit is 150 mPa · s. When the viscosity is in this range, the obtained in-plane encapsulant for an organic EL display element has excellent coatability and is particularly suitable as an in-plane encapsulant for an organic EL display element. The preferable lower limit of the viscosity is 60 mPa · s, the preferred upper limit is 140 mPa · s, the more preferable lower limit is 80 mPa · s, and the more preferable upper limit is 120 mPa · s.
As the E-type viscometer, for example, VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) can be used, and the measurement can be performed with the cone plate of CP1.

The in-plane encapsulant for an organic EL display element of the present invention has a preferable lower limit of surface tension of 15 mN / m and a preferable upper limit of 45 mN / m. When the surface tension is in this range, the obtained in-plane encapsulant for an organic EL display element has excellent coatability and is particularly suitable as an in-plane encapsulant for an organic EL display element. The more preferable lower limit of the surface tension is 20 mN / m, and the more preferable upper limit is 35 mN / m.
In the present specification, the surface tension can be measured by a dynamic wettability tester at 25 ° C.

The in-plane encapsulant for an organic EL display element of the present invention is used by being applied to the inside of a peripheral encapsulant for an organic EL display element containing a water absorbent.
A set of sealants for an organic EL display element used for sealing an organic EL display element, the peripheral sealant that seals the peripheral portion of the organic EL display element, and the organic light emitting material inside the peripheral sealant. The peripheral encapsulant comprises an in-plane encapsulant that coats and seals the laminated body having a layer, and the peripheral encapsulant contains a curable resin, a polymerization initiator, and a water absorber, and the in-plane encapsulant. Is also one of the present inventions, the sealant set for an organic EL display element, which is an in-plane sealant for an organic EL display element of the present invention.

The peripheral sealant contains a curable resin.
Examples of the curable resin used for the peripheral encapsulant include a cationically polymerizable compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group and a vinyl ether group, and a radical having a radically polymerizable group such as a (meth) acryloyl group. Polymerizable compounds can be mentioned.

Examples of the cationically polymerizable compound used in the peripheral encapsulant include an epoxy resin having a bisphenol skeleton, an epoxy resin having a novolak skeleton, an epoxy resin having a naphthalene skeleton, and a dipoxy resin from the viewpoint of easy viscosity adjustment. At least one epoxy resin selected from the group consisting of epoxy resins having a cyclopentadiene skeleton is preferred. Among them, an epoxy resin having a bisphenol skeleton is more preferable, and a bisphenol F type epoxy resin is further preferable.

Further, the peripheral encapsulant preferably contains the compound represented by the above formula (3) as the above-mentioned cationically polymerizable compound from the viewpoint of suppressing the generation of outgas, and the above-mentioned formula (4-1). It is preferable to contain the compound represented by the compound and / or the compound represented by the above formula (4-2).

As the radically polymerizable compound, a (meth) acrylic compound is preferably used.
Examples of the (meth) acrylic compound include epoxy (meth) acrylate, (meth) acrylic acid ester compound, and urethane (meth) acrylate. Of these, epoxy (meth) acrylate is preferable.
In the present specification, the above-mentioned "(meth) acrylic" means acrylic or methacrylic, the above-mentioned "(meth) acrylate" means acrylate or methacrylate, and the above-mentioned "epoxy (meth) acrylate" means. Represents a compound in which all epoxy groups in an epoxy resin are reacted with (meth) acrylic acid.

Among the above-mentioned epoxy (meth) acrylates, commercially available ones include, for example, epoxy (meth) acrylate manufactured by Dycel Ornex, epoxy (meth) acrylate manufactured by Shin-Nakamura Chemical Industry Co., Ltd., and epoxy (meth) acrylate manufactured by Kyoei Co., Ltd. Examples thereof include meta) acrylate and epoxy (meth) acrylate manufactured by Nagase ChemteX Corporation.
Examples of the epoxy (meth) acrylate manufactured by Dycel Ornex include EBECRYL860, EBECRYL3200, EBECRYL3201, EBECRYL3412, EBECRYL3600, EBECRYL3700, EBECRYL3701, EBECRYL3702, EBECRYL3702, EBECRYL3702, EBECRYL3702, EBECRYL3701
Examples of the epoxy (meth) acrylate manufactured by Shin-Nakamura Chemical Industry Co., Ltd. include EA-1010, EA-1020, EA-5323, EA-5520, EA-CHD, EMA-1020 and the like.
Examples of the epoxy (meth) acrylate manufactured by Kyoeisha Chemical Co., Ltd. include epoxy ester M-600A, epoxy ester 40EM, epoxy ester 70PA, epoxy ester 200PA, epoxy ester 80MFA, epoxy ester 3002M, epoxy ester 3002A, and epoxy ester 1600A. Examples thereof include epoxy ester 3000M, epoxy ester 3000A, epoxy ester 200EA, and epoxy ester 400EA.
Examples of the epoxy (meth) acrylate manufactured by Nagase ChemteX include denacole acrylate DA-141, denacole acrylate DA-314, and denacole acrylate DA-911.

From the viewpoint of transparency, moisture permeation prevention, and adhesiveness, the peripheral encapsulant preferably contains a resin having a polyisobutylene skeleton, and the resin having a polyisobutylene skeleton and the radically polymerizable compound. It is more preferable to use in combination.

Examples of the resin having a polyisobutylene skeleton include a homopolymer of isobutene, an isobutylene / isoprene copolymer obtained by copolymerizing isobutylene with isobutylene in an amount of about several% by weight based on the isobutylene, and the isobutylene /. Examples thereof include so-called butyl rubber obtained by cross-linking a double bond site derived from isoprene in an isoprene copolymer.

The peripheral sealant contains a polymerization initiator.
As the polymerization initiator used in the peripheral sealant, a cationic polymerization initiator or a radical polymerization initiator can be used.

Examples of the cationic polymerization initiator used in the peripheral encapsulant include the same cationic polymerization initiator as the above-mentioned cationic polymerization initiator in the in-plane encapsulant for an organic EL display element of the present invention.

As the radical polymerization initiator, a photoradical polymerization initiator or a thermal radical polymerization initiator can be used.

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

Specific examples of the photoradical polymerization initiator include 1-hydroxycyclohexylphenylketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, and 1,2- (dimethylamino). -2-((4-Methylphenyl) Methyl) -1- (4- (4-morpholinyl) phenyl) -1-butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis (2) , 4,6-trimethylbenzoyl) Phenylphosphinoxide, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 1- (4- (2-hydroxyethoxy) -phenyl)- 2-Hydroxy-2-methyl-1-propane-1-one, 1- (4- (phenylthio) phenyl) -1,2-octanedione 2- (O-benzoyloxime), 2,4,6-trimethylbenzoyl Examples thereof include diphenylphosphine oxide, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and the like.

Examples of the thermal radical polymerization initiator include peroxides and azo compounds.
Examples of commercially available thermal radical polymerization initiators include thermal radical polymerization initiators manufactured by Nichiyu Co., Ltd., thermal radical polymerization initiators manufactured by Wako Pure Chemical Industries, Ltd., and the like.
Examples of the thermal radical polymerization initiator manufactured by NOF Corporation include perbutyl O, perhexyl O, perbutyl PV and the like.
Examples of the thermal radical polymerization initiator manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. include V-30, V-65, V-501, V-601 and VPE-0201.

The content of the polymerization initiator used in the peripheral encapsulant is preferably 0.1 part by weight and a preferable upper limit of 10 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the polymerization initiator used in the peripheral encapsulant is within this range, the obtained peripheral encapsulant is excellent in curability, storage stability, and barrier property. The more preferable lower limit of the content of the polymerization initiator used in the peripheral encapsulant is 0.5 parts by weight, and the more preferable upper limit is 5 parts by weight.

The peripheral sealant may contain a thermosetting agent. Examples of the thermosetting agent used for the peripheral encapsulant include the same thermosetting agents as those described above in the in-plane encapsulant for an organic EL display element of the present invention.

The peripheral sealant contains a water absorbent. By containing the water absorbent, the peripheral sealant has an excellent barrier property.
The sealant set for an organic EL display element of the present invention uses the sealant containing the moisture absorber as the peripheral sealant, but the sealant for the organic EL display element of the present invention is used as the in-plane sealant. Therefore, even if these are used in combination, the in-plane encapsulant can be sufficiently cured, and the occurrence of display defects in the obtained organic EL display element can be suppressed.

The preferable lower limit of the water absorption rate of the water absorbent is 10% by weight. When the water absorption rate of the water absorbent is 10% by weight or more, the obtained peripheral encapsulant becomes more excellent in barrier property. A more preferable lower limit of the water absorption rate of the water absorbent is 20% by weight.
Further, although there is no particular preferable upper limit of the water absorption rate of the water absorbent, the practical upper limit is 50% by weight.
The above-mentioned "water absorption rate" means the rate of change in weight when a high-temperature and high-humidity test is performed in which the mixture is left in an atmosphere of a temperature of 85 ° C. and a humidity of 85% for 24 hours. Specifically, when the weight before the high temperature and high humidity test (85 ° C.-85%, 24 hours) is W ₁ , and the weight after the high temperature and high humidity test is W ₂ , it is calculated by the following formula (I).
Water absorption _{(wt%) = ((W 2 -W} 1) / W 1) × 100 (I)

Examples of the material constituting the water absorber include oxides of alkaline earth metals such as calcium oxide, strontium oxide and barium oxide, magnesium oxide and molecular sieves. Of these, oxides of alkaline earth metals are preferable, and calcium oxide is more preferable, from the viewpoint of water absorption.

Regarding the content of the moisture absorber in the peripheral sealant, the preferable lower limit is 5 parts by weight and the preferable upper limit is 60 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the water absorber in the peripheral sealant is in this range, the obtained peripheral sealant has an excellent barrier property and is excellent in the effect of suppressing panel peeling. The more preferable lower limit of the content of the water absorber in the peripheral encapsulant is 10 parts by weight, and the more preferable upper limit is 40 parts by weight.

The peripheral encapsulant may contain other fillers in addition to the water absorbent as long as it does not impair the object of the present invention for the purpose of improving adhesiveness and the like.
Examples of the other fillers include inorganic fillers such as silica, talc and alumina, and organic fillers such as polyester fine particles, polyurethane fine particles, vinyl polymer fine particles and acrylic polymer fine particles. Of these, talc is preferred.

The peripheral sealants are sensitizers, stabilizers, silane coupling agents, surface modifiers, ion exchange resins, curing retarders, reinforcing agents, softeners, plasticizers, viscosity modifiers, UV absorbers, and oxidations. It may contain an additive such as an inhibitor. Examples of these additives include the same as those described above in the in-plane encapsulant for an organic EL display element of the present invention.

The peripheral encapsulant preferably does not contain a solvent from the viewpoint of further suppressing the generation of outgas. The peripheral encapsulant can be excellent in coatability even if it does not contain the solvent.

As a method for producing the above peripheral encapsulant, for example, using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, or a three-roll, a curable resin, a polymerization initiator, and the like are used. Examples thereof include a method of mixing a water absorber and an additive such as a silane coupling agent to be added as needed.

The peripheral sealant is preferably a paste having a viscosity of 150 Pa · s or more and 500 Pa · s or less measured under the condition of 25 ° C. using an E-type viscometer. When the peripheral sealant is a paste having a viscosity in this range, it is superior in both coatability and dispersibility of the moisture absorber. The more preferable lower limit of the viscosity of the peripheral sealant is 200 Pa · s, and the more preferable upper limit is 400 Pa · s. When a solvent is used to adjust the viscosity of the peripheral sealant, it becomes difficult to suppress the generation of outgas.
The viscosity of the peripheral sealant is appropriately 1 from the optimum torque number in each viscosity region on a CP1 cone plate using, for example, VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) as an E-type viscometer. It can be measured by selecting a rotation speed of ~ 100 rpm.

According to the present invention, it is possible to provide an in-plane encapsulant for an organic EL display element having excellent coatability, wet spreadability, and curability. Further, according to the present invention, it is possible to provide a sealant set for an organic EL display element, which comprises a peripheral sealant and an in-plane sealant for the organic EL display element.

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 and Comparative Examples 1 to 5)
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 stirring mixer (manufactured by Shinky Co., Ltd., “AR-250”), and Examples 1 to 8 were used. The in-plane encapsulant for the organic EL display element of Comparative Examples 1 to 5 was produced.
In the table, "X22-163" is a compound represented by the following formula (5).

<Evaluation>
The following evaluations were performed on the in-plane sealants for each organic EL display element obtained in Examples and Comparative Examples. The results are shown in Tables 1-3.

(1) Viscosity The in-plane sealant for each organic EL display element obtained in Examples and Comparative Examples was used at 25 ° C. using an E-type viscometer (“VISCOMETER TV-22” manufactured by Toki Sangyo Co., Ltd.). , Viscosity under the condition of 20 rpm was measured.

(2) Using a wet-spreading pipette, 0.1 mL of the in-plane encapsulant for each organic EL display element obtained in Examples and Comparative Examples was applied onto a glass substrate, and the diameter spread after 1 minute was measured. .. The wettability was evaluated as "◯" when the diameter was 15 mm or more, "Δ" when the diameter was 10 mm or more and less than 15 mm, and "x" when the diameter was less than 10 mm.

(3) Penetration Prevention The in-plane sealants for organic EL display elements obtained in Examples and Comparative Examples were applied onto glass substrates having holes of different sizes. As a result, the case where the sealant did not soak into the hole with a size of 2 μm was marked with “○”, and the hole with a size of 0.5 μm was not found to soak into the hole with a size of 2 μm. The penetration prevention property was evaluated as "Δ" when penetration was confirmed and "x" when penetration was confirmed even in a hole having a size of 0.5 μm.

(4) Low outgassing The in-plane encapsulant for each organic EL display element obtained in Examples and Comparative Examples was weighed and sealed in a vial in an amount of 300 mg, and then heated at 100 ° C. for 30 minutes. It was cured. Further, the vial was heated in a constant temperature oven at 85 ° C. for 100 hours, and the vaporization component in the vial was measured using a gas chromatograph mass spectrometer (“JMS-Q1050” manufactured by JEOL Ltd.).
When the amount of the vaporized component was less than 50 ppm, it was evaluated as “◯”, when it was 50 ppm or more and less than 100 ppm, it was evaluated as “Δ”, and when it was 100 ppm or more, it was evaluated as “×”.

(5) Curability of in-plane sealant and display performance of organic EL display element (manufacturing of a substrate on which a laminate having an organic light emitting material layer is arranged)
A glass substrate (length 45 mm, width 45 mm, thickness 0.7 mm) formed with an ITO electrode having a thickness of 1000 Å was used as the substrate. The substrate is ultrasonically washed with acetone, an alkaline aqueous solution, ion-exchanged water, and isopropyl alcohol for 15 minutes each, then washed with 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 in 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, and others were different. 200 mg of tris (8-quinolinolato) aluminum (Alq ₃ ) was placed in the unglazed 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 200 mg of lithium fluoride was transferred to a tungsten resistance heating boat in this vacuum vapor deposition apparatus, and aluminum was transferred to another tungsten boat. 1.0 g of wire was put in. 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. bottom. 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.

(Preparation of peripheral encapsulant)
The curable resin, the photocationic polymerization initiator, the water absorber, and the silane coupling agent are uniformly mixed at a stirring speed of 3000 rpm using a homodisper type stirring / mixing machine (“Homodisper L type” manufactured by Primix Corporation). A peripheral sealant was prepared by stirring and mixing with the mixture.
The curable resin includes 65 parts by weight of a novolak type epoxy resin (Dow Chemical Co., Ltd., “DEN.431”), and a bisphenol F type epoxy resin (manufactured by DIC Co., Ltd., “EPICLON EXA-830LVP”) 20. 15 parts by weight and 15 parts by weight of a dicyclopentadiene type epoxy resin (“EPICLON HP-7200” manufactured by DIC) were used.
As the photocationic polymerization initiator, 1 part by weight of an aromatic sulfonium salt (manufactured by Midori Chemical Co., Ltd., “DTS-200”) was used.
As the water absorber, 20 parts by weight of calcium oxide (manufactured by Yoshizawa Lime Industry Co., Ltd., "quick lime J1P") was used.
As the silane coupling agent, 1.5 parts by weight of 3-glycidoxypropyltrimethoxysilane ("KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
The viscosity of the obtained peripheral encapsulant measured at 25 ° C. using an E-type viscometer (“VISCOMETER TV-22” manufactured by Toki Sangyo Co., Ltd.) was 250 Pa · s.

(Manufacturing of organic EL display element)
The prepared peripheral encapsulant is applied to the outer periphery of the substrate on which the laminate is arranged so that the line width is 6 mm, and the in-plane encapsulation for each organic EL display element obtained in Examples and Comparative Examples is applied to the inside thereof. After the agent was applied so as to cover the entire laminate, another glass substrate (length 45 mm, width 45 mm, thickness 0.7 mm) was laminated. Then, using a high-pressure mercury lamp, ultraviolet rays having a wavelength of 365 nm are irradiated so that the irradiation amount is 3000 mJ / cm ^2, and further heated at 100 ° C. for 30 minutes to cure the in-plane sealant and the peripheral sealant. An organic EL display element was manufactured. Regarding the in-plane encapsulant for the organic EL display element obtained in Example 4, the in-plane encapsulant and the peripheral encapsulant were cured without heating. Further, the organic EL display element used for the evaluation of the following "(curability of in-plane encapsulant)" was manufactured in the same manner.

(Curability of in-plane sealant)
For the obtained organic EL display element, the curing rate of the in-plane encapsulant was measured at the interface between the peripheral encapsulant and the in-plane encapsulant. As a result, the in-plane encapsulant is designated as "○" when the curing rate is 80% or more, "Δ" when it is 50% or more and less than 80%, and "×" when it is less than 50%. The curability of was evaluated.

(Display performance of organic EL display element)
After exposing the obtained organic EL display element to an environment of 85 ° C. and 85% RH for 1000 hours, a voltage of 10 V is applied to check the light emitting state (presence / absence of dark spots and pixel peripheral quenching) of the organic EL display element. It was visually observed. Organic EL display as "○" when light is emitted uniformly without dark spots or peripheral quenching, "△" when slight dark spots or peripheral quenching is observed, and "×" when the non-light emitting part is significantly enlarged. The display performance of the element was evaluated.

According to the present invention, it is possible to provide an in-plane encapsulant for an organic EL display element having excellent coatability, wet spreadability, and curability. Further, according to the present invention, it is possible to provide a sealant set for an organic EL display element, which comprises a peripheral sealant and an in-plane sealant for the organic EL display element.

Claims (6)

An in-plane encapsulant for an organic EL display element, which is used by being applied to the inside of a peripheral encapsulant for an organic EL display element containing a water absorbent.
Contains a curable resin and a cationic polymerization initiator,
The curable resin contains a cycloalkene oxide-type alicyclic epoxy compound having a silicone skeleton.
An organic EL display characterized in that the viscosity of the entire in-plane encapsulant for an organic EL display element measured at 25 ° C. and 20 rpm is 50 mPa · s or more and 150 mPa · s or less using an E-type viscometer. In-plane encapsulant for devices. The in-plane encapsulant for an organic EL display element according to claim 1, wherein the cycloalkene oxide-type alicyclic epoxy compound having a silicone skeleton is a compound represented by the following formula (1).

In the formula (1), n represents an integer of 0 or more and 10 or less. The in-plane encapsulant for an organic EL display element according to claim 2, wherein the cycloalkene oxide-type alicyclic epoxy compound having a silicone skeleton is a compound represented by the following formula (2).

The organic EL display element according to claim 1, 2 or 3, wherein the content of the cycloalkene oxide-type alicyclic epoxy compound having the silicone skeleton in 100 parts by weight of the curable resin is 20 parts by weight or more and 70 parts by weight or less. In-plane sealant. The in-plane encapsulant for an organic EL display element according to claim 1, 2, 3 or 4, wherein the curable resin contains a compound represented by the following formula (3).

In the formula (3), R ^{1 to} R ¹⁸ are hydrocarbon groups which may contain a hydrogen atom, a halogen atom, an oxygen atom or a halogen atom, and may be the same or different from each other. May be good. X is a bond, an oxygen atom, an alkylene group having 1 to 5 carbon atoms, an oxycarbonyl group, an alkyleneoxycarbonyl group having 2 to 5 carbon atoms, or a secondary amino group. A set of sealants for organic EL display elements used to seal organic EL display elements.
It is composed of a peripheral sealant that seals the peripheral portion of the organic EL display element and an in-plane sealant that coats and seals a laminate having an organic light emitting material layer inside the peripheral sealant.
The peripheral sealant contains a curable resin, a polymerization initiator, and a water absorbent, and contains.
The in-plane sealant is a sealant set for an organic EL display element, which is the in-plane sealant for an organic EL display element according to claim 1, 2, 3, 4 or 5.