JP2019147963A - Sealing agent for organic electroluminescence display element - Google Patents

Abstract

To provide a sealing agent for an organic electroluminescence display element, which exhibits excellent adhesiveness even to a flexible substrate or the like and can suppress a display failure due to deterioration of the element.SOLUTION: The sealing agent for an organic electroluminescence display element comprises a cationically polymerizable compound and a cationic polymerization initiator, in which the cationically polymerizable compound contains a hydrolyzable cationically polymerizable compound that has a cationically polymerizable group and an ether bond or ester bond and produces hydrolysis products, all of which have a cationically polymerizable group when the ether bond or the ester bond is broken by hydrolysis. When the sealing agent weighed at 300 mg is sealed in a vial container, heated at 100°C for 30 minutes to cure, or irradiated with ultraviolet rays at a dose of 1500 mJ/cmand then heated at 80°C for 30 minutes to cure, and further heated at 85°C for 100 hours, the generated amount of outgas is 100 ppm or less.SELECTED DRAWING: None

Description

The present invention relates to an organic electroluminescence display element sealing agent that is excellent in adhesiveness to a flexible substrate and the like and can suppress display defects due to deterioration of the element.

In recent years, research on organic optical devices using organic thin film elements such as organic electroluminescence (hereinafter also referred to as “organic EL”) display elements and organic thin film solar cell elements has been advanced. The organic thin film element can be easily produced by vacuum deposition, solution coating, or the like, and thus has excellent productivity.

The 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. When electrons are injected from one electrode into the organic light emitting material layer and holes are injected from the other electrode, electrons and holes are combined in the organic light emitting material layer to perform self-light emission. Compared with a liquid crystal display element or the like that requires a backlight, the visibility is better, the thickness can be reduced, and direct current low voltage driving is possible.

However, such an organic EL display element has a problem that when the organic light emitting material layer and the electrode are exposed to the outside air, the light emission characteristics thereof are rapidly deteriorated and the life is shortened. Therefore, for the purpose of improving the stability and durability of the organic EL display element, in the organic EL display element, a sealing technique for shielding the organic light emitting material layer and the electrode from moisture and oxygen in the atmosphere is indispensable. Yes.

Patent Document 1 discloses a method for sealing a top emission organic EL display element or the like by filling a sealing agent between organic EL display element substrates. However, the conventional sealing agent has a problem that it tends to deteriorate the device by generating outgas during and after curing.

JP 2001-357773 A

An object of this invention is to provide the sealing agent for organic electroluminescent display elements which is excellent in adhesiveness also to a flexible substrate etc., and can suppress the display defect by element deterioration.

The present invention is an organic electroluminescent display element sealing agent comprising a cationic polymerizable compound and a cationic polymerization initiator, wherein the cationic polymerizable compound has a cationic polymerizable group and an ether bond or an ester bond. In addition, when the ether bond or the ester bond is cleaved by hydrolysis, all degradation products contain a hydrolyzable cationically polymerizable compound having a cationically polymerizable group, and weigh 300 mg in a vial. And then cured by heating at 100 ° C. for 30 minutes, or after being irradiated with ultraviolet rays of 1500 mJ / cm ² , cured by heating at 80 ° C. for 30 minutes, and further heated at 85 ° C. for 100 hours. Is a sealant for organic electroluminescence display elements having 100 ppm or less.
The present invention is described in detail below.

The present inventor is that the cause of outgas generation in a conventional sealant is that an ether bond or an ester bond of a cationic polymerizable compound contained in the sealant is hydrolyzed by an acid derived from a polymerization initiator or the like. I thought. Therefore, the present inventor examined using a cationically polymerizable compound that does not have an ether bond and an ester bond, but the resulting sealant was able to suppress outgassing, but had a large cure shrinkage. In particular, sufficient adhesion to a flexible substrate or the like was not obtained. Therefore, as a result of further intensive studies, the inventor has a cationically polymerizable group and an ether bond or an ester bond, and all degradation products are cationically polymerized even when the ether bond or the ester bond is cleaved by hydrolysis. By using a hydrolyzable cationically polymerizable compound having a functional group and setting the amount of outgassing during curing and after curing to a specific value or less, it has excellent adhesion to flexible substrates and the like, and the element The present inventors have found that a sealing agent for organic EL display elements that can suppress display defects due to deterioration of the liquid crystal can be obtained, and have completed the present invention.

The sealing agent for an organic EL display element of the present invention measures 300 mg in a vial and encloses it, and is cured by heating at 100 ° C. for 30 minutes, or after irradiation with ultraviolet rays of 1500 mJ / cm ² at 80 ° C. The upper limit of the amount of outgas generation when heated for 30 minutes and cured at 85 ° C. for 100 hours is 100 ppm. When the outgas generation amount is 100 ppm or less, the sealing agent for organic EL display elements of the present invention can sufficiently suppress display defects due to deterioration of the elements. A preferable upper limit of the outgas generation amount is 50 ppm, and a more preferable upper limit is 30 ppm.
The smaller the amount of outgas generated, the better. There is no particular lower limit, but it is substantially 5 ppm or more.
The outgas generation amount can be measured using a gas chromatograph mass spectrometer (for example, JMS-Q1050 (manufactured by JEOL Ltd.)).

The sealing agent for organic EL display elements of this invention contains a cationically polymerizable compound.
The cationic polymerizable compound has a cationic polymerizable group and an ether bond or an ester bond, and when the ether bond or the ester bond is cleaved by hydrolysis, all the decomposition products have a cationic polymerizable group. And a hydrolyzable cationically polymerizable compound (hereinafter, also referred to as “hydrolyzable cationically polymerizable compound according to the invention”). The hydrolyzable cationically polymerizable compound according to the present invention has an ether bond or an ester bond, so that the curing shrinkage does not become too large, and the obtained sealing agent for organic EL display elements has excellent adhesion to a flexible substrate or the like. In addition, when the ether bond or the ester bond is cleaved by hydrolysis, it is possible to prevent the decomposition product from causing outgassing because all decomposition products have a cationic polymerizable group.
By using the hydrolyzable cation polymerizable compound according to the present invention as the cation polymerizable compound and not using other components that cause outgassing, or reducing the content even when used. The outgas generation amount can be in the above-described range.

Examples of the cationic polymerizable group include an epoxy group, an oxetanyl group, and a vinyl ether group. Of these, an epoxy group is preferable.

Specific examples of the hydrolyzable cationically polymerizable compound according to the present invention include 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (compound represented by the following formula (1)). 3-ethyl-3 (((3-ethyloxetane-3-yl) methoxy) methyl) oxetane (compound represented by the following formula (2)), diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate (Compound represented by the following formula (3)) and the like. Especially, since the sealing agent for organic EL display elements obtained becomes the thing excellent in adhesiveness with respect to a flexible substrate etc., the alicyclic epoxy compound which has an ether bond or an ester bond is preferable, and following formula (1) or following A compound represented by the formula (2) is more preferable, and a compound represented by the following formula (1) is more preferable.

As what is marketed among the hydrolyzable cationically polymerizable compounds concerning this invention, Celoxide 2021P (made by Daicel), OXT-221 (made by Toagosei Co., Ltd.), etc. are mentioned, for example.

The sealing agent for organic EL display elements of the present invention is a cationic polymerizable compound having no ether bond or ester bond, an ether bond or an ester as the other cationic polymerizable compound as long as the object of the present invention is not impaired. When the ether bond or the ester bond has a bond but is cleaved by hydrolysis, at least a part of the decomposed product may contain a cationic polymerizable compound having no cationic polymerizable property. It is preferable not to contain the said other cationically polymerizable compound from a viewpoint of making the adhesiveness and the effect which suppresses the display defect by deterioration of an element compatible.

In the case where the other cationic polymerizable compound is contained, the present invention in 100 parts by weight of the whole cationic polymerizable compound is used from the viewpoint of achieving both the adhesion to a flexible substrate and the like and the effect of suppressing the display defect due to the deterioration of the element. A preferred lower limit of the content of the hydrolyzable cationically polymerizable compound is 20 parts by weight, a more preferred lower limit is 50 parts by weight, and a still more preferred lower limit is 70 parts by weight.

The sealing agent for organic EL display elements of the present invention contains a cationic polymerization initiator.
Examples of the cationic polymerization initiator include a photocationic polymerization initiator that generates a protonic acid or a Lewis acid by light irradiation, and a thermal cationic polymerization initiator that generates a protonic acid or a Lewis acid by heating. These are not particularly limited as long as they are ionic acid generating types or nonionic acid generating types.

Among the above-mentioned photocationic polymerization initiators, examples of the ionic photoacid-generating photocationic polymerization initiator include an anion moiety of BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , or (BX ₄ ) ⁻ (however, , X represents a phenyl group substituted with at least two fluorine or trifluoromethyl groups), an aromatic sulfonium salt, an aromatic iodonium salt, an aromatic diazonium salt, an aromatic ammonium salt, or , (2,4-cyclopentadien-1-yl) ((1-methylethyl) benzene) -Fe salt and the like.

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

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

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

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

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

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

Examples of commercially available photocationic polymerization initiators include, for example, DTS-200 (manufactured by Midori Chemical Co., Ltd.), UVI6990, UVI6974 (all manufactured by Union Carbide), SP-150, SP-170 (all ADEKA), FC-508, FC-512 (all from 3M), Irgacure 290 (BASF), PI 2074 (Rhodia) and the like.

As the thermal cationic polymerization initiator, the anion moiety is BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , or (BX ₄ ) ⁻ (where X is substituted with at least two fluorine or trifluoromethyl groups. A sulfonium salt, a phosphonium salt, a quaternary ammonium salt, a diazonium salt, an iodonium salt, or the like.

Examples of the sulfonium salts include triphenylsulfonium boron tetrafluoride, triphenylsulfonium hexafluoride antimony, triphenylsulfonium hexafluoride arsenic, tri (4-methoxyphenyl) sulfonium hexafluoride arsenic, diphenyl (4-phenylthiophenyl). ) Sulfonium arsenic hexafluoride and the like.

Examples of the phosphonium salt include ethyltriphenylphosphonium antimony hexafluoride and tetrabutylphosphonium antimony hexafluoride.

Examples of the quaternary ammonium salt include dimethylphenyl (4-methoxybenzyl) ammonium hexafluorophosphate, dimethylphenyl (4-methoxybenzyl) ammonium hexafluoroantimonate, dimethylphenyl (4-methoxybenzyl) ammonium tetrakis (penta). Fluorophenyl) borate, dimethylphenyl (4-methylbenzyl) ammonium hexafluorophosphate, dimethylphenyl (4-methylbenzyl) ammonium hexafluoroantimonate, dimethylphenyl (4-methylbenzyl) ammonium hexafluorotetrakis (pentafluorophenyl) borate , Methylphenyldibenzylammonium, methylphenyldibenzylammonium hexafluoroantimony Hexafluorophosphate, methylphenyldibenzylammonium tetrakis (pentafluorophenyl) borate, phenyltribenzylammonium tetrakis (pentafluorophenyl) borate, dimethylphenyl (3,4-dimethylbenzyl) ammonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl-N-benzylanilinium antimony hexafluoride, N, N-diethyl-N-benzylanilinium tetrafluoride, N, N-dimethyl-N-benzylpyridinium antimony hexafluoride, N, N -Diethyl-N-benzylpyridinium trifluoromethanesulfonic acid and the like.

Examples of commercially available thermal cationic polymerization initiators include, for example, Sun-Aid SI-60, Sun-Aid SI-80, Sun-Aid SI-B3, Sun-Aid SI-B3A, and Sun-Aid SI-B4 (all Sanshin Chemical Industries, Ltd. Manufactured by CXC-1612, CXC-1821 (all manufactured by King Industries).

Especially, since the said sealing agent for organic EL display elements can suppress generation | occurrence | production of outgas more, it is preferable that the said cationic polymerization initiator contains a quaternary ammonium salt.

The content of the cationic polymerization initiator is preferably 0.05 parts by weight and preferably 10 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. When the content of the cationic polymerization initiator is within this range, the obtained sealing agent for organic EL display elements is excellent in curability, storage stability, and moisture resistance of the cured product. The minimum with more preferable content of the said cationic polymerization initiator is 0.1 weight part, and a more preferable upper limit is 5 weight part.

The sealing agent for organic EL display elements of the present invention may contain other components in addition to the cationic polymerizable compound and the cationic polymerization initiator as long as the object of the present invention is not impaired.

The sealing agent for organic EL display elements of the present invention contains a silane coupling agent as the other component for the purpose of improving the adhesion between the sealing agent for organic EL display elements of the present invention and the substrate. However, it is preferable not to contain a silane coupling agent from the viewpoint of suppressing the generation of outgas.

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

When the silane coupling agent is contained, the upper limit of the content of the silane coupling agent is preferably 0.5 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. When the content of the silane coupling agent is 0.5 parts by weight or less, a higher adhesion improvement effect can be exhibited while suppressing generation of outgas and bleeding out of excess silane coupling agent. The upper limit with more preferable content of the said silane coupling agent is 0.1 weight part.

The sealing agent for organic EL display elements of the present invention may contain a stabilizer as the other component from the viewpoint of improving storage stability.
Examples of the stabilizer include amine compounds such as benzylamine.

The sealing agent for organic EL display elements of this invention may contain a thermosetting agent as said other component.
Examples of the thermosetting agent include hydrazide compounds, imidazole derivatives, acid anhydrides, dicyandiamides, guanidine derivatives, modified aliphatic polyamines, addition products of various amines and epoxy resins, and the like.
Examples of the hydrazide compound include 1,3-bis (hydrazinocarbonoethyl-5-isopropylhydantoin).
Examples of the imidazole derivatives include 1-cyanoethyl-2-phenylimidazole, N- (2- (2-methyl-1-imidazolyl) ethyl) urea, 2,4-diamino-6- (2′-methylimidazolyl- (1 ′))-ethyl-s-triazine, N, N′-bis (2-methyl-1-imidazolylethyl) urea, N, N ′-(2-methyl-1-imidazolylethyl) -adipamide, 2- Examples include phenyl-4-methyl-5-hydroxymethylimidazole and 2-phenyl-4,5-dihydroxymethylimidazole.
Examples of the acid anhydride include tetrahydrophthalic anhydride, ethylene glycol bis (anhydro trimellitate), and the like.
These thermosetting agents may be used alone or in combination of two or more.

The sealing agent for organic EL display elements of this invention may contain a surface modifier as said other component. By containing the said surface modifier, the flatness of the coating film of the sealing agent for organic EL display elements of this invention can be improved.
Examples of the surface modifier include surfactants and leveling agents.

Examples of the surface modifier include silicone-based, acrylic-based, and fluorine-based ones.
Examples of commercially available surface modifiers include BYK-302, BYK-331 (both manufactured by Big Chemie Japan), UVX-272 (manufactured by Enomoto Kasei), Surflon S-611 ( AGC Seimi Chemical Co., Ltd.).

The sealing agent for organic EL display elements of the present invention is a compound or ion exchange that reacts with the acid generated in the sealing agent for organic EL display elements in order to improve the durability of the element electrodes as the other components. A resin may be contained.

Examples of the compound that reacts with the generated acid include substances that neutralize the acid, for example, alkali metal carbonates or bicarbonates, or alkaline earth metal carbonates or bicarbonates. 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 both ion exchange type can be used, and in particular, a cation exchange type or a both ion exchange type capable of adsorbing chloride ions. Is preferred.

Moreover, the sealing agent for organic EL display elements of this invention is a hardening retarder, a reinforcing agent, a softener, a plasticizer, a viscosity modifier, a ultraviolet absorber, an antioxidant as other components as necessary. Various known additives such as these may be contained.

Examples of the method for producing the sealing agent for organic EL display elements of the present invention include a cationically polymerizable compound using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, or a three roll. And a method of mixing a cationic polymerization initiator and other components added as necessary.

The sealing agent for organic EL display elements of the present invention has a preferable lower limit of 5 mPa · s and a preferable upper limit of 500 mPa · s measured using an E-type viscometer at 25 ° C. By the said viscosity being this range, the sealing agent for organic EL display elements of this invention will become more excellent by application property. A more preferable lower limit of the viscosity is 10 mPa · s, and a more preferable upper limit is 100 mPa · s.
The viscosity is, for example, a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) as an E-type viscometer, and a rotational speed of 1 to 100 rpm as appropriate from the optimum torque number in each viscosity region using a CP1 cone plate. Can be measured by selecting.

The sealing agent for organic EL display elements of the present invention is particularly preferably used as an in-plane sealing agent that covers and seals a laminate having an organic light emitting material layer.

ADVANTAGE OF THE INVENTION According to this invention, the sealing agent for organic electroluminescent display elements which is excellent in adhesiveness also to a flexible substrate etc. and can suppress the display defect by deterioration of an element can be provided.

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

Example 1
As a hydrolyzable cationically polymerizable compound according to the present invention, 100 parts by weight of a compound represented by the above formula (1) (manufactured by Daicel, “Celoxide 2021P”) and dimethylphenyl (4-methoxy) as a thermal cationic polymerization initiator are used. Benzyl) ammonium tetrakis (pentafluorophenyl) borate (King Industries, "CXC-1821") 0.5 part by weight, using a stirring mixer (Sinky, "AR-250"), stirring speed 3000rpm The mixture was stirred and mixed uniformly to prepare an organic EL display element sealant.
300 mg of the obtained sealing agent for organic EL display element was weighed and sealed in a vial, and cured by heating at 100 ° C. for 30 minutes. Further, this vial was heated in a constant temperature oven at 85 ° C. for 100 hours, and the vaporized component in the vial was used as an outgas generation amount, and measured using a gas chromatograph mass spectrometer (“JMS-Q1050” manufactured by JEOL Ltd.). did. The results are shown in Table 1.

(Examples 2-6, Comparative Examples 1-3)
Each material described in Table 1 was stirred and mixed in the same manner as in Example 1 in accordance with the blending ratio described in Table 1, and sealed for organic EL display elements in Examples 2 to 6 and Comparative Examples 1 to 3. A stop agent was prepared.
About each obtained sealing agent for organic EL display elements, it carried out similarly to Example 1, and measured the outgas generation amount. The results are shown in Table 1. In addition, about the sealing agent obtained in Example 2, instead of heating at 100 degreeC for 30 minutes, after irradiating with ultraviolet rays 1500mJ / cm < ² >, it heated at 80 degreeC for 30 minutes and was hardened.

<Evaluation>
The following evaluation was performed about each sealing agent for organic EL display elements obtained by the Example and the comparative example. The results are shown in Table 1.

(1) Viscosity About each sealing agent for organic EL display elements obtained in Examples and Comparative Examples, a viscosity at 25 ° C. using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., “VISCOMETER TV-22”). Was measured.

(2) Adhesiveness to flexible substrate The sealant for each organic EL display element obtained in Examples and Comparative Examples is taken in the center of a 20 mm × 50 mm polycarbonate plate (manufactured by Takiron Co., Ltd.). The same size polycarbonate plates were stacked to spread the sealant. The sealant was cured in that state (Examples 1 to 3 and 6 and Comparative Examples 1 to 3 were cured by heating at 100 ° C. for 30 minutes and obtained in Example 2. The sealing agent was irradiated with ultraviolet rays at 1500 mJ / cm ² and then cured by heating at 80 ° C. for 30 minutes to obtain an adhesion test piece. The adhesive strength of the obtained adhesion test piece was measured using EZgraph (manufactured by Shimadzu Corporation). At that time, “◯” indicates that the adhesive strength was 1.0 kgf / cm ² or more, “△” indicates that the adhesive strength was 0.5 kgf / cm ² or more and less than 1.0 kgf / cm ² , and adhesive strength. Was less than 0.5 kgf / cm ² was evaluated as “x”, and the adhesion to the flexible substrate was evaluated.

(3) Curing (Each sealing agent obtained in Examples 1, 3 to 6 and Comparative Examples 1 to 3) About each sealing agent for organic EL display elements obtained in the curable examples and comparative examples Is cured by heating at 100 ° C. for 30 minutes, and the encapsulant obtained in Example 2 is heated before and after curing when irradiated with ultraviolet rays of 1500 mJ / cm ² and then heated at 80 ° C. for 30 minutes. The amount was measured using a DSC apparatus (manufactured by Agilent Technologies, “UMA600”), and the reaction rate of the epoxy group was derived from the following formula.
Epoxy group reaction rate (%) = 100 × (Heat generation amount before curing−Heat generation amount after curing) / Heat generation amount before curing The case where the reaction rate of the epoxy group was 90% or more “◯”, 70% The curability was evaluated as “Δ” when less than 90% and “×” when less than 70%.

(4) Display performance of organic EL display element (production of a substrate on which a laminate having an organic light emitting material layer is disposed)
A glass substrate (length 30 mm, width 30 mm, thickness 0.7 mm) on which an ITO electrode was formed to a thickness of 1000 mm was used as the substrate. The substrate was ultrasonically washed with acetone, an aqueous alkali solution, ion-exchanged water, and isopropyl alcohol for 15 minutes each, then washed with boiled isopropyl alcohol for 10 minutes, and further UV-ozone cleaner (manufactured by Nippon Laser Electronics Co., Ltd., The last treatment was performed with “NL-UV253”).
Next, this substrate is fixed to the substrate folder of the vacuum deposition apparatus, and 200 mg of N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (α-NPD) is put into an unglazed crucible in other different ways. 200 mg of tris (8-quinolinolato) aluminum (Alq ₃ ) was put in an unglazed crucible, and the inside of the vacuum chamber was depressurized to 1 × 10 ⁻⁴ Pa. Thereafter, the crucible containing α-NPD was heated and α-NPD was deposited on the substrate at a deposition rate of 15 Å / s to form a 600 正 孔 hole transport layer. Next, the crucible containing Alq ₃ was heated to form an organic light emitting material layer having a thickness of 600 で at a deposition rate of 15 Å / s. Thereafter, the substrate on which the hole transport layer and the organic light emitting material layer are formed is transferred to another vacuum vapor deposition apparatus, and 200 mg of lithium fluoride is added to a tungsten resistance heating boat in the vacuum vapor deposition apparatus, and aluminum is added to another tungsten boat. 1.0 g of wire was added. Then, after reducing the pressure in the vapor deposition unit of the vacuum vapor deposition apparatus to 2 × 10 ⁻⁴ Pa and depositing 5 μm of lithium fluoride at a deposition rate of 0.2 kg / s, deposit 1000 μm of aluminum at a rate of 20 kg / s. did. The inside of the vapor deposition unit was returned to normal pressure with nitrogen, and the substrate on which the laminate having the organic light emitting material layer was arranged was taken out.

(Coating with inorganic material film A)
A mask having an opening was placed so as to cover the entire laminated body of the substrate on which the obtained laminated body was arranged, and an inorganic material film A was formed by a plasma CVD method.
In the plasma CVD method, SiH ₄ gas and nitrogen gas are used as source gases, the flow rates of each are SiH ₄ gas 10 sccm, nitrogen gas 200 sccm, RF power 10 W (frequency 2.45 GHz), chamber temperature 100 ° C., chamber The test was performed under the condition that the internal pressure was 0.9 Torr.
The formed inorganic material film A had a thickness of about 1 μm.

(Formation of resin protective film)
Each of the organic EL display element sealants obtained in Examples and Comparative Examples was discharged onto a glass substrate by an inkjet method with a discharge amount of 80 pL using an inkjet discharge device (manufactured by Microjet Co., “Nano Printer 300”). Applied. At the time of application, the film thickness was adjusted to 20 μm or less. Next, the organic EL display element sealant was cured (Examples 1 to 3 and Comparative Examples 1 to 3 were cured by heating at 100 ° C. for 30 minutes, Example 2). The sealing agent obtained in (1) was irradiated with ultraviolet rays at 1500 mJ / cm ² and then cured by heating at 80 ° C. for 30 minutes to form a resin protective film.

(Coating with inorganic material film B)
After forming the resin protective film, a mask having an opening was placed so as to cover the entire resin protective film, and an inorganic material film B was formed by a plasma CVD method to obtain an organic EL display element.
In the plasma CVD method, SiH ₄ gas and nitrogen gas are used as source gases, the flow rates of each are SiH ₄ gas 10 sccm, nitrogen gas 200 sccm, RF power 10 W (frequency 2.45 GHz), chamber temperature 100 ° C., chamber The test was performed under the condition that the internal pressure was 0.9 Torr.
The formed inorganic material film B had a thickness of about 1 μm.

(Light emission state of organic EL display element)
The obtained organic EL display device was exposed for 100 hours under the conditions of a temperature of 85 ° C. and a humidity of 85%, and then a voltage of 10 V was applied, and the light emission state of the device (the presence or absence of light emission and dark spots) was visually observed. . Evaluation was made as “◯” when there was no dark spot or peripheral quenching, and “◯” when the dark spot or peripheral quenching was observed, and “X” when the non-light emitting part was significantly enlarged.

ADVANTAGE OF THE INVENTION According to this invention, the sealing agent for organic electroluminescent display elements which is excellent in adhesiveness also to a flexible substrate etc. and can suppress the display defect by deterioration of an element can be provided.

Claims (5)

A sealing agent for an organic electroluminescence display element comprising a cationically polymerizable compound and a cationic polymerization initiator,
The cationic polymerizable compound has a cationic polymerizable group and an ether bond or an ester bond, and when the ether bond or the ester bond is cleaved by hydrolysis, all the decomposition products have a cationic polymerizable group. Containing a hydrolyzable cationically polymerizable compound having
300 mg is weighed and sealed in a vial and cured by heating at 100 ° C. for 30 minutes, or after irradiation with 1500 mJ / cm ^{2 of} ultraviolet light, cured by heating at 80 ° C. for 30 minutes, and further at 85 ° C. An encapsulant for organic electroluminescence display elements, wherein the amount of outgas generated when heated for 100 hours is 100 ppm or less. The encapsulant for an organic electroluminescence display element according to claim 1, wherein the hydrolyzable cationically polymerizable compound contains an alicyclic epoxy compound having an ether bond or an ester bond. The sealing compound for organic electroluminescence display elements according to claim 2, wherein the alicyclic epoxy compound having an ether bond or an ester bond is a compound represented by the following formula (1).

The encapsulant for an organic electroluminescence display element according to claim 1, 2 or 3, wherein the content of the hydrolyzable cationic polymerizable compound in 100 parts by weight of the whole cationic polymerizable compound is 20 parts by weight or more. . The encapsulant for an organic electroluminescence display element according to claim 1, wherein the cationic polymerization initiator contains a quaternary ammonium salt.