JP5966113B1 - Sealant for organic electroluminescence display element - Google Patents

Abstract

An object of this invention is to provide the sealing agent for organic electroluminescent display elements which is excellent in barrier property and can suppress panel peeling. The present invention contains a cationically polymerizable compound, a photocationic polymerization initiator, and a water-absorbing filler, and the cationically polymerizable compound contains a bisphenol F-type epoxy resin and an epoxy resin having a flexible skeleton, The water-absorbing filler is a sealing agent for organic electroluminescence display elements that is calcium oxide and / or magnesium oxide and has a total surface area of 10 to 100 m 2 per 100 g of the cationic polymerizable compound.

Description

The present invention relates to a sealing agent for organic electroluminescence display elements that has excellent barrier properties and can suppress panel peeling.

An organic electroluminescence (hereinafter, also referred to as “organic EL”) display element has a laminated structure in which an organic light emitting material layer is sandwiched between a pair of electrodes facing each other, and the organic light emitting material layer is formed from one electrode on the organic light emitting material layer. When electrons are injected and holes are injected from the other electrode, the electrons and holes are combined in the organic light emitting material layer to emit light. Thus, since the organic EL display element performs self-emission, it has better visibility than a liquid crystal display element that requires a backlight, can be reduced in thickness, and can be driven by a DC low voltage. Has the advantage.

The organic light-emitting material layer and electrodes constituting the organic EL display element have a problem that the characteristics are easily deteriorated by moisture, oxygen, and the like. Therefore, in order to obtain a practical organic EL display element, it is necessary to extend the life by blocking the organic light emitting material layer and the electrode from the atmosphere. As a method for blocking the organic light emitting material layer and the electrode from the atmosphere, an organic EL display element is sealed with a sealant (for example, Patent Document 1). When sealing an organic EL display element with a sealant, an inorganic film called a passivation film is usually provided on a laminate having an organic light emitting material layer in order to sufficiently suppress the transmission of moisture, oxygen, and the like. A method of sealing the top with a sealant is used.

In recent years, instead of a bottom emission type organic EL display element that extracts light emitted from an organic light emitting material layer from the side of the substrate surface on which the light emitting element is formed, a top emission type organic element that extracts light from the upper surface side of the organic light emitting layer is used. EL display elements have attracted attention. This method has an advantage that it has a high aperture ratio and is driven at a low voltage, which is advantageous for extending the life. In such a top emission type organic EL display element, since the upper surface side of the light emitting layer needs to be transparent, a transparent moisture-proof substrate such as glass is interposed on the upper surface side of the light emitting element via a transparent sealing resin. It seals by laminating | stacking a material (for example, refer patent document 2).
However, in such a top emission type organic EL display element, there is no space for disposing a desiccant so as not to shield the light extraction direction, and it is difficult to obtain a sufficient moisture-proofing effect and the life is short. There was a problem of becoming.

JP 2007-115692 A JP 2009-051980 A

An object of this invention is to provide the sealing agent for organic electroluminescent display elements which is excellent in barrier property and can suppress panel peeling.

The present invention contains a cationically polymerizable compound, a photocationic polymerization initiator, and a water-absorbing filler. The cationically polymerizable compound contains a bisphenol F-type epoxy resin and an epoxy resin having a flexible skeleton, and The water-absorbing filler is a sealing agent for an organic electroluminescence display element which is calcium oxide and / or magnesium oxide and has a total surface area of 10 to 100 m ² per 100 g of the cationic polymerizable compound.
The present invention is described in detail below.

The present inventors have studied to add calcium oxide and / or magnesium oxide as a water-absorbing filler in order to improve the barrier property (moisture permeability prevention property) of the encapsulant for organic EL display elements. However, when such a water-absorbing filler is added to the sealant for organic EL display elements, it exhibits excellent water absorption, but it has a high expansion rate and absorbs moisture, thereby causing defects such as panel peeling. There was a problem of causing.
Accordingly, as a result of intensive studies, the present inventors used a combination of a bisphenol F type epoxy resin and an epoxy resin having a flexible skeleton as a cationic polymerizable compound used for an organic EL display element sealing agent, By making the total surface area of the filler within a specific range, it was found that an encapsulant for organic EL display elements having excellent barrier properties and capable of suppressing panel peeling can be obtained, and the present invention has been completed.

The sealing agent for organic EL display elements of this invention contains a cationically polymerizable compound.
The cationically polymerizable compound contains a bisphenol F type epoxy resin and an epoxy resin having a flexible skeleton. By using a combination of the bisphenol F type epoxy resin and the epoxy resin having the flexible skeleton, the sealing agent for organic EL display elements of the present invention uses calcium oxide and / or magnesium oxide as a water absorbing filler. Can also prevent panel peeling.

The bisphenol F-type epoxy resin has a role of adjusting the coating property of the obtained sealing agent for organic EL display elements and suppressing a decrease in barrier property due to the resin component.
A bisphenol F type epoxy resin having a flexible skeleton such as a caprolactone-modified bisphenol F type epoxy resin is treated as an “epoxy resin having a flexible skeleton”.

From the viewpoint of applicability, the bisphenol F-type epoxy resin is preferably used in combination of a solid and a liquid at 25 ° C.
When the bisphenol F-type epoxy resin is used in combination with a solid and a liquid at 25 ° C., the content ratio of the solid and the liquid at 25 ° C. is solid at 25 ° C. Bisphenol F type epoxy resin: Bisphenol F type epoxy resin which is liquid at 25 ° C. = 1: 5 to 1:50 is preferable. When the content ratio of solid and liquid at 25 ° C. is within this range, the obtained sealing agent for organic EL display elements is more excellent in coatability. The content ratio of solid and liquid at 25 ° C. is bisphenol F-type epoxy resin solid at 25 ° C. by weight ratio: bisphenol F-type epoxy resin liquid at 25 ° C. = 1: 10 to 1:30 More preferably.

The preferable lower limit of the content of the bisphenol F type epoxy resin in 100 parts by weight of the cationic polymerizable compound is 5.0 parts by weight, and the preferable upper limit is 70 parts by weight. When the content of the bisphenol F-type epoxy resin is in this range, the cured product of the obtained sealing agent for organic EL display elements is excellent in barrier properties while suppressing panel peeling. The minimum with more preferable content of the said bisphenol F-type epoxy resin is 10 weight part, and a more preferable upper limit is 60 weight part.

The epoxy resin having the flexible skeleton is represented by the structure represented by the following formula (1-1), the structure represented by the following formula (1-2), and the following formula (1-3) as the flexible skeleton. Or a structure represented by the following formula (1-4), more preferably a structure represented by the following formula (1-1), in the following formula (1-1) More preferably, m has a structure of 4 or 6.

In formula (1-1), m is an integer of 1-15. In formula (1-2), n is an integer of 1-5. In formula (1-3), R ¹ and R ² are hydrocarbon groups having 1 to 3 carbon atoms, and may be the same or different.

The epoxy resin having the flexible skeleton preferably has a glass transition temperature (Tg) of less than 100 ° C. By using an epoxy resin having a flexible skeleton having a Tg of less than 100 ° C., the effect of suppressing panel peeling is improved. The Tg of the epoxy resin having the flexible skeleton is more preferably less than 50 ° C.
In the present specification, the “glass transition temperature” means a temperature at which a maximum due to micro-Brownian motion appears, among the maximum of loss tangent (tan δ) obtained by dynamic viscoelasticity measurement. It can be measured by a conventionally known method using an elasticity measuring device.

Specific examples of the epoxy resin having a flexible skeleton include, for example, an alkylene oxide modified product or a caprolactone modified product, (poly) ethylene glycol diglycidyl ether, (poly) 1,3-propanediol diglycidyl ether, ( (Poly) 1,4-butanediol diglycidyl ether, (poly) 1,6-hexanediol diglycidyl ether and other (poly) alkanediol diglycidyl ether, bis (2- (3,4-epoxycyclohexyl) ethyl) poly Examples thereof include dimethylsiloxane, polydimethylsiloxane diglycidyl ether, and polyisobutylene diglycidyl ether.

Examples of commercially available epoxy resins having the flexible skeleton include jER YL7410, jER YED216, jER YL7175-500 (all manufactured by Mitsubishi Chemical Corporation), EPICLON 705, EPICLON 707, EPICLON 726, EPICLON EXA-4816, EPICLON. EXA-4822, EPICLON EXA-4850 (all manufactured by DIC), Denacol EX-212, Denacol EX-830, Denacol EX-931 (all manufactured by Nagase ChemteX), KF-105, X-22-169 ( All of them are manufactured by Shin-Etsu Chemical Co., Ltd.).

The preferable lower limit of the content of the epoxy resin having the flexible skeleton in 100 parts by weight of the cationic polymerizable compound is 1.0 part by weight, and the preferable upper limit is 20 parts by weight. When the content of the epoxy resin having the flexible skeleton is in this range, the barrier property is improved while suppressing panel peeling of the obtained organic EL display element. The minimum with more preferable content of the epoxy resin which has the said flexible skeleton is 2.0 weight part, and a more preferable upper limit is 15 weight part.

The sealing agent for organic EL display elements of this invention contains a photocationic polymerization initiator.
The photocationic polymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid by light irradiation, and may be an ionic photoacid generating type or a nonionic photoacid generating type. May be.

Examples of the ionic photoacid-generating photocationic polymerization initiator include a cation moiety that is aromatic sulfonium, aromatic iodonium, aromatic diazonium, aromatic ammonium, or (2,4-cyclopentadien-1-yl). ) ((1-methylethyl) benzene) -Fe cation, and the anion moiety is BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , or (BX ₄ ) ⁻ (where X is at least two fluorine atoms) Or an onium salt composed of a phenyl group substituted with a trifluoromethyl group).

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

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

The content of the cationic photopolymerization initiator is preferably 0.1 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 photopolymerization initiator is 0.1 parts by weight or more, the obtained sealing agent for organic EL display elements is more excellent in photocurability. When the content of the cationic photopolymerization initiator is 10 parts by weight or less, the curing reaction of the obtained sealing agent for organic EL display elements does not become too fast, and the workability becomes excellent, and the cured product becomes more uniform. Can be. The minimum with more preferable content of the said photocationic polymerization initiator is 0.5 weight part, and a more preferable upper limit is 5 weight part.

The sealing agent for organic EL display elements of this invention contains a water absorbing filler.
The water-absorbing filler is calcium oxide and / or magnesium oxide. By containing calcium oxide and / or magnesium oxide as the water-absorbing filler, the obtained sealing agent for organic EL display elements has excellent barrier properties.
Especially, it is preferable to contain the calcium oxide whose specific surface area is less than 10.0 m < ² > / g.

The total surface area of the water-absorptive filler, the lower limit is 10 m ² per cationically polymerizable compound 100 g, the upper limit is 100 m ^2. When the total surface area of the water-absorbing filler is 10 m ² or more per 100 g of the cationic polymerizable compound, the cured product of the obtained sealing agent for organic EL display elements is excellent in barrier properties. When the total surface area of the water-absorbing filler is 100 m ² or less, the effect of suppressing panel peeling and crack generation is excellent. A preferred lower limit of the total surface area of the water-absorptive filler is 20 m ^2, a preferred upper limit is 80 m ^2.
The total surface area of the water-absorbing filler is calculated from the content of the water-absorbing filler and the BET specific surface area. Specifically, for example, it is calculated from the BET specific surface area measured using nitrogen gas with a specific surface area measuring apparatus (manufactured by Shimadzu Corporation, ASAP-2000).

The content of the water-absorbing filler is such that a preferable lower limit is 1.0 part by weight and a preferable upper limit is 50 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. When the content of the water-absorbing filler is within this range, the cured product of the obtained sealing agent for organic EL display elements is excellent in barrier properties while suppressing panel peeling and crack generation. The minimum with more preferable content of the said water absorbing filler is 2.0 weight part, and a more preferable upper limit is 20 weight part.

The sealing agent for organic EL display elements of the present invention may contain other fillers in addition to the above water-absorbing filler within a range not impairing the object of the present invention for the purpose of improving adhesiveness. Good.
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 because of its excellent effect of improving moisture resistance.

The content of the other filler is such that a preferred lower limit is 5 parts by weight and a preferred upper limit is 100 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. When the content of the other filler is 5 parts by weight or more, the effect of improving the adhesiveness is excellent. When the content of the other filler is 100 parts by weight or less, the obtained sealing agent for organic EL display elements is more excellent in applicability. The minimum with more preferable content of the said other filler is 10 weight part, and a more preferable upper limit is 80 weight part.

The sealing agent for organic EL display elements 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, addition products of various amines and epoxy resins, and the like.
Examples of the hydrazide compound include 1,3-bis (hydrazinocarbonoethyl-5-isopropylhydantoin), sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide, and the like.
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.

Examples of commercially available thermosetting agents include SDH (manufactured by Nippon Finechem), ADH (manufactured by Otsuka Chemical), Amicure VDH, Amicure VDH-J, Amicure UDH (all manufactured by Ajinomoto Fine Techno Co., Ltd.). ) And the like.

The content of the thermosetting agent is preferably 0.5 parts by weight and preferably 30 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. When the content of the thermosetting agent is 0.5 parts by weight or more, the obtained sealing agent for organic EL display elements is more excellent in thermosetting. When the content of the thermosetting agent is 30 parts by weight or less, the obtained sealing agent for organic EL display elements is excellent in storage stability, and the cured product is excellent in moisture resistance. The minimum with more preferable content of the said thermosetting agent is 1 weight part, and a more preferable upper limit is 15 weight part.

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

Examples of the sensitizer include anthracene compounds such as 9,10-dibutoxyanthracene, thioxanthone compounds such as 2,4-diethylthioxanthone, and 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.

The content of the sensitizer is preferably 0.05 parts by weight and preferably 3 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. 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 minimum with more preferable content of the said sensitizer is 0.1 weight part, and a more preferable upper limit is 1 weight part.

The sealing agent for organic EL display elements of the present invention preferably contains a stabilizer for the purpose of improving storage stability.
Examples of the stabilizer include amine compounds and aminophenol type epoxy resins.

The content of the stabilizer is preferably 0.001 part by weight and preferably 2 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. When the content of the stabilizer is within this range, the effect of improving the storage stability of the obtained sealing agent for organic EL display elements is suppressed while suppressing curing inhibition. The minimum with more preferable content of the said stabilizer is 0.05 weight part, and a more preferable upper limit is 1 weight part.

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

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

The content of the silane coupling agent is preferably 0.1 parts by weight and preferably 10 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. When the content of the silane coupling agent is within this range, the effect of improving the adhesiveness of the obtained sealing agent for organic EL display elements while suppressing bleed-out due to excess silane coupling agent It becomes. The minimum with more preferable content of the said silane coupling agent is 0.5 weight part, and a more preferable upper limit is 5 weight part.

The sealing agent for organic EL display elements of the present invention may contain a surface modifier as long as the object of the present invention is not impaired. By containing the surface modifier, the flatness of the coating film can be imparted to the organic EL display element sealant of the present invention.
Examples of the surface modifier include surfactants and leveling agents.

Examples of the surfactant and the leveling agent include silicon-based, acrylic-based, and fluorine-based ones.
Examples of commercially available surfactants and leveling agents include BYK-345, BYK-340 (all manufactured by Big Chemie Japan), and Surflon S-611 (manufactured by AGC Seimi Chemical). Can be mentioned.

The encapsulant for organic EL display elements of the present invention may contain an ion exchange resin in order to improve the durability of the element electrode as long as the object of the present invention is not impaired.

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 range which does not inhibit the objective of this invention, and is a hardening retarder, a reinforcing agent, a softener, a plasticizer, a viscosity modifier, and an ultraviolet absorber as needed. Further, various known additives such as antioxidants 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 photopolymerization initiator, a water-absorbing filler, and an additive added as necessary.

As for the sealing agent for organic EL display elements of this invention, the preferable minimum of the viscosity in 25 degreeC measured using the E-type viscosity meter is 100 Pa.s, and a preferable upper limit is 500 Pa.s. When the viscosity is within this range, the obtained sealing agent for organic EL display elements of the present invention is superior in coating properties and shape stability after coating. The more preferable lower limit of the viscosity is 150 Pa · s, the more preferable upper limit is 450 Pa · s, the still more preferable lower limit is 200 mPa · s, and the still more preferable upper limit is 400 Pa · 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 on a CP7 cone plate. Can be measured by selecting.

As for the sealing agent for organic EL display elements of this invention, the preferable minimum of the glass transition temperature (Tg) of hardened | cured material is 85 degreeC, and a preferable upper limit is 180 degreeC. When the glass transition temperature of the cured product is 85 ° C. or higher, the barrier property is improved. By the glass transition temperature of the said hardened | cured material being 180 degrees C or less, it will become excellent by the effect which suppresses a crack and panel peeling. The minimum with a more preferable glass transition temperature of the said hardened | cured material is 100 degreeC, and a more preferable upper limit is 150 degreeC.
In addition, the hardened | cured material which measures said Tg can be obtained by irradiating 3000m ultraviolet rays with 3000mJ / cm < ² > using a high pressure mercury lamp etc., and also heat-processing at 80 degreeC for 30 minutes.

The shape of the sealing portion formed in the organic EL display element sealant of the present invention is not particularly limited as long as it is a shape that can protect the laminate having the organic light emitting material layer from the outside air. The shape may be completely covered, a closed pattern may be formed in the periphery of the laminate, or a pattern having a shape in which a part of the opening is provided in the periphery of the laminate is formed. However, it can be suitably used for sealing the peripheral portion of the laminate.

ADVANTAGE OF THE INVENTION According to this invention, the sealing agent for organic electroluminescent display elements which is excellent in barrier property and can suppress panel peeling 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 cationic polymerizable compound, 20 parts by weight of a solid bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation, “jER 4005P”), 70 parts by weight of a liquid bisphenol F type epoxy resin (manufactured by DIC, “EPICLON EXA-830LVP”) And 10 parts by weight of an epoxy resin having a structure in which m in the formula (1-1) is 4 as a flexible skeleton (manufactured by Mitsubishi Chemical Corporation, “jER YL7410”, also referred to as epoxy resin A having a flexible skeleton) In addition, 0.1 parts by weight of 9,10-dibutoxyanthracene as a sensitizer was dissolved at 110 ° C. over 1 hour, and then an aromatic iodonium salt (“PI2074”, produced by Rhodia) as a photocationic polymerization initiator. 3.0 parts by weight was added and dissolved by heating at 60 ° C. for 1 hour. Thereafter, 2.0 parts by weight of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM-403”) as a silane coupling agent, and calcium oxide (manufactured by Yoshizawa Lime Industry Co., Ltd., “Quicklime” as a water-absorbing filler. “J1P”, 20 parts by weight of specific surface area 2.5 m ² / g), and 30 parts by weight of talc (manufactured by Nippon Talc Co., “FG-15”) as other fillers were added and stirred mixer (manufactured by Shinky Corporation, “AR -250 "), and the mixture was uniformly stirred and mixed at a stirring speed of 2000 rpm to prepare an organic EL display element sealant.

(Examples 2 to 12, Comparative Examples 1 to 5)
Each material described in Tables 1 and 2 was stirred and mixed in the same manner as in Example 1 according to the blending ratios described in Tables 1 and 2 to prepare an organic EL display element sealant.
In Table 1, “epoxy resin B having a flexible skeleton” is an epoxy resin having a structure in which m in the above formula (1-1) is 6, and “epoxy resin C having a flexible skeleton” is An epoxy resin having a structure in which m in the above formula (1-1) is 2.

<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 Tables 1 and 2.

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

(2) Glass transition temperature of cured product About each sealing agent for organic EL display elements obtained in Examples and Comparative Examples, ultraviolet light at 365 nm is irradiated at 3000 mJ / cm ² and further heated at 80 ° C. for 30 minutes. Then, the sealant was cured to produce a film. The obtained film was measured for dynamic viscoelasticity at 30 Hz to 200 ° C. and 10 Hz using a dynamic viscoelasticity measuring apparatus (“DVA-200” manufactured by IT Measurement Control Co., Ltd.), and loss tangent (tan δ). Was determined as the glass transition temperature.

(3) Barrier property of hardened | cured material The following Ca-TEST was performed about each sealing agent for organic EL display elements obtained by the Example and the comparative example.
First, a mask having a plurality of openings of 2 mm × 2 mm was put on a 30 mm × 30 mm glass substrate, and Ca was vapor-deposited by a vacuum vapor deposition machine. The conditions for the vapor deposition were that the inside of the vapor deposition unit of the vacuum vapor deposition apparatus was depressurized to 2 × 10 ⁻³ Pa and a film of 2000 μm of Ca was formed at a vapor deposition rate of 5.0 kg / s. A glass substrate in which a glass substrate on which Ca is deposited is moved into a glow box controlled at a dew point (−60 ° C. or higher), and a sealing agent for each organic EL display element obtained in Examples and Comparative Examples is applied to the surface. Were pasted together. At this time, bonding was performed so that the deposited Ca exists at positions of 2 mm, 4 mm, and 6 mm from the end face of the glass substrate. Next, ultraviolet light of 365 nm was irradiated at 3000 mJ / cm ² , and further, the sealant was cured by heating at 80 ° C. for 30 minutes to prepare a Ca-TEST substrate. The obtained Ca-TEST substrate was exposed to high-temperature and high-humidity conditions of 85 ° C. and 85% RH, and the moisture penetration distance per hour was observed from the disappearance of Ca.
As a result of Ca-TEST, “◎” indicates that the time required for the moisture penetration distance to reach 6 mm is 1000 hours or more, “◯” indicates that the time is 500 hours or more and less than 1000 hours, and “◯” indicates 100 hours or more and 500 hours. When it was less than “Δ”, and when it was less than 100 hours, “x”, the barrier property of the cured product was evaluated.

(4) Panel adhesion state (production of a substrate on which a laminate having an organic light emitting material layer is disposed)
A glass substrate (length 25 mm, width 25 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 of 10 mm × 10 mm was arranged was taken out.

(Coating with inorganic material film A)
A mask having an opening of 13 mm × 13 mm 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 are 10 sccm and 200 sccm, RF power is 10 W (frequency: 2.45 GHz), chamber temperature is 100 ° C., and chamber pressure is 0. The test was performed at 9 Torr.
The formed inorganic material film A had a thickness of about 1 μm.

(Formation of resin protective film)
For each organic EL display element obtained in Examples and Comparative Examples, a substrate on which a laminated body coated with an inorganic material film A is placed in a vacuum apparatus, and a heating boat installed in the vacuum apparatus. 0.5 g of the sealing agent is added, the pressure is reduced to 10 Pa, and the organic EL display element sealing agent is heated at 200 ° C. to a 11 mm × 11 mm square portion including the laminate, and the thickness is 0.5 μm. Vacuum deposition was performed so that Thereafter, ultraviolet rays having a wavelength of 365 nm were irradiated using a high pressure mercury lamp in a vacuum environment so that the irradiation amount was 3000 mJ / cm ² to cure the organic EL display element sealant to form a resin protective film.

(Coating 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 film B is formed by plasma CVD to form an organic EL display element. Obtained.
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.

(Observation of panel adhesion)
The adhesion state of the panel after exposing the obtained organic EL display element to an environment of 85 ° C. and 85% RH for 500 hours was visually observed. As a result, there was no panel peeling, and no insertion into the sealant was seen `` ◎ '', while insertion into the sealant was confirmed slightly, but there was no panel peeling `` ○ '', The case where panel peeling was partially confirmed was evaluated as “Δ”, and the case where panel peeling was confirmed from the majority was evaluated as “x”, and the adhesion state of the panel was evaluated.

(5) Reliability of organic EL display element An organic EL display element obtained in the same manner as in “(3) Panel adhesion state” above was exposed to an environment of 85 ° C. and 85% RH for 500 hours. The light emission state (the presence or absence of dark spots and pixel periphery quenching) of the organic EL display element was visually observed. The reliability of the organic EL display element was evaluated with “◯” when the light was emitted uniformly without dark spots or peripheral quenching, and “X” when the dark spot or peripheral quenching was observed even slightly.

ADVANTAGE OF THE INVENTION According to this invention, the sealing agent for organic electroluminescent display elements which is excellent in barrier property and can suppress panel peeling can be provided.

Claims (2)

A cationically polymerizable compound, a photocationic polymerization initiator, and a water-absorbing filler; wherein the cationically polymerizable compound contains a bisphenol F-type epoxy resin and an epoxy resin having a flexible skeleton; A sealing agent for organic electroluminescence display elements , which is calcium oxide and / or magnesium oxide and has a total surface area of 10 to 100 m ² per 100 g of the cationic polymerizable compound ,
The epoxy resin having the flexible skeleton is represented by the structure represented by the following formula (1-1), the structure represented by the following formula (1-2), and the following formula (1-3) as the flexible skeleton. that structure, or organic electroluminescence display element sealing agents you characterized by having a structure represented by the following formula (1-4).

In formula (1-1), m is an integer of 1-15. In formula (1-2), n is an integer of 1-5. In formula (1-3), R ¹ and R ² are hydrocarbon groups having 1 to 3 carbon atoms, and may be the same or different. The sealing agent for organic electroluminescence display elements according to claim 1 , wherein the water-absorbing filler contains calcium oxide having a specific surface area of less than 10.0 m ² / g.