Sealing agent, sealing material for organic electroluminescent element, and organic electroluminescent display device

Abstract

This encapsulant for an organic electroluminescent element comprises a radically-polymerizable compound, a photopolymerization initiator, and a stable-radical-type compound having stable radicals. The radically-polymerizable compound contains an unsaturated alicyclic monomer having a radically-polymerizable group and an unsaturated aliphatic hydrocarbon ring.

Description

Technical Field

[0001] The present invention relates to a sealing agent for an organic electroluminescence element, a sealing material, and an organic electroluminescence display device.

Background Art

[0002] An organic electroluminescence element (hereinafter also referred to as an organic EL element) has attracted attention as an element body capable of emitting light with high luminance. However, the organic EL element has a problem that it deteriorates due to oxygen and moisture, and the light emission characteristics deteriorate. To solve this problem, technologies for sealing the organic EL element to prevent deterioration have been studied.

[0003] As one of the sealing methods, for example, Patent Document 1 describes a sealing agent for an organic EL element that contains a polymerizable compound and a polymerization initiator, has a viscosity at 25°C of 5 to 50 mPa·s, a surface tension at 25°C of 15 to 35 mN / m, and a water content at 25°C after standing in an environment of 25°C and 50% RH for 24 hours of 1000 ppm or less.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As a sealing agent for an organic EL element, a thermosetting sealing agent and a photocurable sealing agent are known. The photocurable sealing agent does not require heating during sealing, so that a sealing material can be formed without exposing the organic EL element to high heat, and has an advantage that deformation and deterioration of the organic EL element due to high heat are suppressed.

[0006] In recent years, the required characteristics of electronic devices have increased. For example, there is a demand for a sealing material that can achieve higher reliability for organic EL elements.

[0007] However, with conventional photocurable sealants, it has been difficult to sufficiently suppress the generation of dark spots in durability tests under high temperature and high humidity.

[0008] Therefore, an object of the present invention is to provide a sealant for organic EL elements that can significantly suppress the generation of dark spots under high temperature and high humidity. Another object of the present invention is to provide a sealing material formed from the sealant for organic EL elements and an organic EL display device including the sealing material.

Means for Solving the Problems

[0009] The present invention relates to, for example, the following <1> to <11>. <1> A sealant for an organic electroluminescence element, containing a radically polymerizable compound, a photopolymerization initiator, and a stable radical type compound having a stable radical, wherein the radically polymerizable compound includes an unsaturated alicyclic monomer having a radically polymerizable group and an unsaturated aliphatic hydrocarbon ring. <2> The sealant according to <1>, wherein the unsaturated aliphatic hydrocarbon ring is a cycloalkene ring. <3> The sealant according to <1> or <2>, wherein the content of the unsaturated alicyclic monomer is 3 to 90% by mass based on the total amount of the radically polymerizable compound. <4> The sealant according to any one of <1> to <3>, wherein the stable radical is a nitroxide radical. <5> The sealant according to any one of <1> to <4>, wherein the content of the stable radical type compound is 1 to 15000 mass ppm with respect to 100 parts by mass of the radically polymerizable compound. <6> The sealant according to any one of <1> to <5>, wherein the radically polymerizable compound further includes an acyclic monomer having a radically polymerizable group and no ring structure. <7> The encapsulant according to any one of <1> to <6>, wherein the radically polymerizable compound further includes an aromatic monomer having a radically polymerizable group and an aromatic ring. <8> The encapsulant according to any one of <1> to <7>, wherein the radically polymerizable compound further includes a fluorine-containing monomer having a radically polymerizable group and a fluorine group. <9> An encapsulant material including a cured product of the encapsulant according to any one of <1> to <8>. <10> An organic electroluminescence display device including an organic electroluminescence element and the encapsulant material according to <9> that encapsulates the organic electroluminescence element.

Advantages of the Invention

[0010] According to the present invention, there is provided an encapsulant for an organic EL element capable of significantly suppressing the generation of dark spots under high temperature and high humidity. Further, according to the present invention, there are provided an encapsulant material formed from the encapsulant for an organic EL element and an organic EL display device including the encapsulant material.

Modes for Carrying Out the Invention

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail.

[0012] In this specification, the notation "X to Y" in the description of a numerical range means X or more and Y or less, unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% or more and 5 mass% or less".

[0013] In the notation of a group (atomic group) in this specification, a notation that does not indicate whether it is substituted or unsubstituted includes both those having no substituent and those having a substituent. For example, the "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

[0014] The notation "(meth)acryl" in this specification includes both acryl and methacryl. The same applies to similar notations such as "(meth)acrylate".

[0015] <Sealant> The sealant of this embodiment contains a radically polymerizable compound, a photopolymerization initiator, and a stable radical type compound having a stable radical. In the sealant of this embodiment, the radically polymerizable compound includes an unsaturated alicyclic monomer having a radically polymerizable group and an unsaturated aliphatic hydrocarbon ring.

[0016] The sealant of this embodiment is for sealing an organic electroluminescence element. That is, the sealant of this embodiment is used to seal an organic EL element to manufacture an organic EL display device. Since the sealant of this embodiment contains a photopolymerization initiator, it is a photocurable sealant.

[0017] By sealing the organic EL element with the sealant of this embodiment, the generation of dark spots under high temperature and high humidity is significantly suppressed.

[0018] The reason why the above effects are achieved by the sealant of this embodiment is not necessarily limited, but the following reasons are considered. According to the findings of the present inventors, in the sealant of this embodiment, the unsaturated aliphatic hydrocarbon ring in the unsaturated alicyclic monomer functions as an oxygen trap, so the polymerization inhibition by oxygen during polymerization is suppressed, and the unreacted monomer in the cured product (sealing material) is reduced. Therefore, in this embodiment, it is considered that the deterioration of the organic EL element and the generation of dark spots due to the intrusion of the unreacted monomer from the defects of the inorganic protective film on the organic EL element are suppressed. In addition, since the unsaturated alicyclic monomer of the sealant of this embodiment has an unsaturated aliphatic hydrocarbon ring, the remaining unsaturated aliphatic hydrocarbon ring in the cured product (sealing material) functions as an oxygen trap, and it is considered that the deterioration of the organic EL element and the generation of dark spots due to the intrusion of oxygen are suppressed.

[0019] In addition, the encapsulant of the present embodiment is excellent in dischargeability from a coating device. Specifically, according to the encapsulant of the present embodiment, when discharged from the coating device, bending of the discharged liquid, variation in the amount of the discharged liquid, etc. are suppressed, and good dischargeability is maintained. Thereby, according to the encapsulant of the present embodiment, a coating film with significantly less thickness unevenness and excellent flatness can be formed. Also, according to the encapsulant of the present embodiment, an encapsulating material that contributes to improving the reliability of the organic EL element can be formed.

[0020] The reason why the above effects are achieved by the encapsulant of the present embodiment is not necessarily limited, but the following reasons are considered. According to the findings of the present inventors, in a conventional photocurable encapsulant, when discharging the encapsulant from a coating device, bending of the discharged liquid, variation in the amount of the discharged liquid, etc. occur, and as a result, thickness unevenness occurs in the coating film, and the flatness of the coating film may decrease. As a cause of this, in a photocurable encapsulant, unintended polymerization is likely to occur before use of the encapsulant (for example, during storage, transportation, etc.), and it is considered that fine particles generated by the polymerization narrow the flow path of the coating device, causing bending of the discharged liquid, variation in the amount of the discharged liquid, etc. In the encapsulant of the present embodiment, by containing a stable radical type compound, although it is a photocurable encapsulant, unintended polymerization before use (for example, during storage, transportation, etc.) and generation of particles due to the polymerization are significantly suppressed. For this reason, in the encapsulant of the present embodiment, coating defects caused by particles are suppressed, and excellent dischargeability from the coating device and high flatness of the coating film after coating are realized.

[0021] In addition, in conventional photocurable encapsulants, during light irradiation, due to uneven film thickness, variations in irradiation amount, etc., reaction points such as photoinitiators, radical species generated from photoinitiators, and radical species generated during the polymerization process may remain in the cured body. And due to the remaining of such reaction points, further polymerization may occur in the cured body after the encapsulation operation, and the cured body may shrink upon curing. Usually, an inorganic protective film with a thickness of about 1 μm is provided between the organic EL element and the encapsulant (cured body of the encapsulant). However, when curing shrinkage occurs, a load is applied to the inorganic protective film and cracks are likely to occur, and the reliability of the organic EL element may decrease due to the intrusion of water or oxygen from the cracks. By containing a stable radical type compound, the encapsulant of the present embodiment makes it difficult for the above-mentioned reaction points to remain in the cured body, and further polymerization from the reaction points is also suppressed. In addition, by containing an unsaturated alicyclic monomer, the encapsulant of the present embodiment makes it difficult for unreacted monomers to remain in the cured body as described above, so the remaining of reaction points is reduced, and further polymerization in the cured body is suppressed. Therefore, according to the encapsulant of the present embodiment, alteration due to reaction points is less likely to occur, damage to the inorganic protective film due to curing shrinkage can be suppressed, and an encapsulant that contributes to improving the reliability of the organic EL element can be formed.

[0022] (Radical polymerizable compound) The radical polymerizable compound may be any compound that can be polymerized by active species generated from a photoinitiator described later. The radical polymerizable compound may be used alone or in combination of two or more.

[0023] The radical polymerizable compound can be said to be a compound having a radical polymerizable group. Examples of the radical polymerizable group include a vinyl group, a (meth)acryloyl group, an allyl group, a vinyl ether group, a vinyl ester group, a (meth)acrylamide group, etc. Among these, the (meth)acryloyl group is particularly preferred.

[0024] In the encapsulant of the present embodiment, the radical polymerizable compound includes an unsaturated alicyclic monomer having a radical polymerizable group and an unsaturated aliphatic hydrocarbon ring.

[0025] The unsaturated alicyclic hydrocarbon ring of the unsaturated alicyclic monomer may be a monocyclic ring or a condensed ring. Examples of the unsaturated alicyclic hydrocarbon ring include a cycloalkene ring, a cycloalkadiene ring, a cycloalkatriene ring, etc. From the viewpoint that the above effects are more remarkable, a cycloalkene ring is preferable.

[0026] Examples of the cycloalkene ring include a cyclopentene ring, a cyclohexene ring, a dihydrodicyclopentadiene ring, a norbornene ring, a cycloheptene ring, a cyclooctene ring, etc. From the viewpoint of excellent reactivity of the unsaturated bond portion, the cycloalkene ring is preferably selected from the group consisting of a cyclopentene ring, a cyclohexene ring, a dihydrodicyclopentadiene ring and a norbornene ring, and more preferably selected from the group consisting of a cyclopentene ring and a dihydrodicyclopentadiene ring.

[0027] The unsaturated alicyclic monomer may be a monofunctional compound having one radical polymerizable group, or may be a polyfunctional compound having two or more radical polymerizable groups. The number of radical polymerizable groups in the unsaturated alicyclic monomer may be, for example, 1 to 6, preferably 1 to 4, more preferably 1 to 3, and still more preferably 1 to 2.

[0028] The unsaturated alicyclic monomer may be a compound having one unsaturated alicyclic hydrocarbon ring, or may be a compound having two or more unsaturated alicyclic hydrocarbon rings. The number of unsaturated alicyclic hydrocarbon rings in the unsaturated alicyclic monomer may be, for example, 1 to 6, preferably 1 to 4, more preferably 1 to 3, and still more preferably 1 to 2.

[0029] Examples of the unsaturated alicyclic monomer include dicyclopentenyl (meth) acrylate, dicyclopentenyl oxyethyl (meth) acrylate, dicyclopentenyl oxypropyl oxyethyl (meth) acrylate, (norborn-5-en-2-yl) methyl acrylate, etc.

[0030] The proportion of the unsaturated alicyclic monomer in the radically polymerizable compound may be, for example, 3% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 15% by mass or more. Thereby, the above effects are exhibited more remarkably. Further, the proportion of the unsaturated alicyclic monomer in the radically polymerizable compound may be, for example, 90% by mass or less, preferably 70% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass or less. Thereby, the above effects are exhibited more remarkably. That is, the proportion of the unsaturated alicyclic monomer in the radically polymerizable compound may be, for example, 3 to 90% by mass, 3 to 70% by mass, 3 to 50% by mass, 3 to 40% by mass, 5 to 90% by mass, 5 to 70% by mass, 5 to 50% by mass, 5 to 40% by mass, 10 to 90% by mass, 10 to 70% by mass, 10 to 50% by mass, 10 to 40% by mass, 15 to 90% by mass, 15 to 70% by mass, 15 to 50% by mass, or 15 to 40% by mass.

[0031] The radically polymerizable compound may contain a plurality of components including an unsaturated alicyclic monomer.

[0032] The radically polymerizable compound preferably contains, for example, a polyfunctional compound having two or more radically polymerizable groups. The number of radically polymerizable groups in the polyfunctional compound may be, for example, 2 to 6, preferably 2 to 4. By using a polyfunctional compound, the photocurability tends to be further improved.

[0033] From the viewpoint of obtaining well-balanced various properties as a sealing material, as the polyfunctional compound, a bifunctional compound having two radically polymerizable groups is preferable.

[0034] The radically polymerizable compound may contain a monofunctional compound having one radically polymerizable group. From the viewpoint of facilitating the adjustment of the polymerization rate, physical properties of the cured product, etc., the radically polymerizable compound preferably contains a polyfunctional compound and a monofunctional compound.

[0035] Note that the unsaturated alicyclic monomer may correspond to a polyfunctional compound or a monofunctional compound.

[0036] When the radical-polymerizable compound contains a polyfunctional compound and a monofunctional compound, the proportion of the polyfunctional compound in the radical-polymerizable compound may be, for example, 30% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, even more preferably 80% by mass or more, and may be 85% by mass or more or 90% by mass or more. Also, the proportion of the polyfunctional compound in the polymerizable compound may be, for example, 100% by mass or less, preferably 95% by mass or less. That is, the proportion of the polyfunctional compound in the radical-polymerizable compound may be, for example, 30 to 100% by mass, 30 to 95% by mass, 50 to 100% by mass, 50 to 95% by mass, 60 to 100% by mass, 60 to 95% by mass, 70 to 100% by mass, 70 to 95% by mass, 80 to 100% by mass, 80 to 95% by mass, 85 to 100% by mass, 85 to 95% by mass, 90 to 100% by mass, or 90 to 95% by mass.

[0037] As the polyfunctional compound, a polyfunctional (meth)acrylic compound having two or more (meth)acryloyl groups is preferable. Specific examples of the polyfunctional (meth)acrylic compound include Bis(1-(meth)acryloxy-2-hydroxypropyl) phthalate, bis(2-(meth)acryloxyethyl) phosphate, bis((meth)acryloxy-2-hydroxypropyloxy)diethylene glycol, bisphenol A di(meth)acrylate, bisphenol A di-(3-(meth)acryloxyethyl) ether, bisphenol A di-(3-(meth)acryloxy-2-hydroxypropyl) ether, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di-(3-(meth)acryloxy-2-hydroxypropyl) ether, 1,4-butanediol di(meth)acrylate, 1,3-butanediol bis((meth)acryloxypropionate), 1,4-butanediol bis((meth)acryloxypropionate), 2-butene-1,4-diol di(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, 2,2-dimethyl-1,3-propanediol di(meth)acrylate, dipentaerythritol ether di(meth)acrylate, diphenolic acid di-(3-(meth)acryloxy-2-hydroxypropyl) ether, dipropylene glycol di(meth)acrylate, 7,7,9-trimethyl-3,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,2-ethanediol di(meth)acrylate, 1,2-ethanediol bis((meth)acryloxypropionate), 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,4-phenylene di(meth)acrylate, 1-phenyl-1,2-ethanediol di(meth)acrylate, polyoxyethyl-2,2-di(p-hydroxyphenyl)propane di(meth)acrylate, 1,2-propanediol di(meth)acrylate, 1,3-propanediol di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, tetrabromobisphenol A di-(3-(meth)acryloxy-2-hydroxypropyl) ether, tetrachlorobisphenol A di-(3-(meth)acryloxy-2-hydroxypropyl) ether, tetraethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 2,2,4-trimethyl-1,3-pentanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, bisphenol A epoxy di(meth)acrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluoro-1,10-decane diacrylate and other difunctional (meth)acrylic compounds; 1,2,4-butanetriol tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, polyoxypropyl trimethylolpropane tri(meth)acrylate, silicone tri(meth)acrylate, 1,3,5-tri(meth)acryloyl hexahydro-s-triazine, trimethylolethane tri(meth)acrylate, 1,1,1-trimethylolpropane tri(meth)acrylate, 1,2,3-trimethylolpropane tri(meth)acrylate, 1,1,1-trimethylolpropane tris((meth)acryloxypropionate), 1,2,3-trimethylolpropane tris((meth)acryloxypropionate), tris-(2-(meth)acryloxyethyl) isocyanurate and other trifunctional (meth)acrylic compounds; pentaerythritol tetra(meth)acrylate, pentaerythritol tetrakis((meth)acryloxypropionate) and other tetrafunctional (meth)acrylic compounds; etc. can be mentioned.

[0038] As the monofunctional compound, a monofunctional (meth)acrylic compound having one (meth)acryloyl group is preferable. Specific examples of the monofunctional (meth)acrylic compound include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, cyclohexyl (meth)acrylate, lauryl (meth)acrylate, n-octyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate (2-HPA), dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-trimethylphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-(meth)acryloyloxyhexahydrophthalic acid, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalic acid, EO-modified phenol (meth)acrylate, EO-modified cresol (meth)acrylate, EO-modified nonylphenol (meth)acrylate, PO-modified nonylphenol (meth)acrylate, ethoxylated-o-phenylphenol (meth)acrylate, m-phenoxybenzyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, 1H,1H,2H,2H-tridecafluorooctyl (meth)acrylate, and the like.

[0039] The radically polymerizable compound preferably contains a compound having an aromatic ring (hereinafter also referred to as an aromatic monomer). Thereby, the moisture permeability of the cured body tends to be further reduced.

[0040] When the radically polymerizable compound contains an aromatic monomer, the proportion of the aromatic monomer in the radically polymerizable compound may be, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more, and may be 5% by mass or more. Also, the proportion of the aromatic monomer in the radically polymerizable compound may be, for example, 70% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less, and may be 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less. That is, the proportion of the aromatic monomer in the radically polymerizable compound may be, for example, 1 to 70% by mass, 1 to 60% by mass, 1 to 50% by mass, 1 to 40% by mass, 1 to 30% by mass, 1 to 20% by mass, 1 to 15% by mass, 1 to 10% by mass, 2 to 70% by mass, 2 to 60% by mass, 2 to 50% by mass, 2 to 40% by mass, 2 to 30% by mass, 2 to 20% by mass, 2 to 15% by mass, 2 to 10% by mass, 3 to 70% by mass, 3 to 60% by mass, 3 to 50% by mass, 3 to 40% by mass, 3 to 30% by mass, 3 to 20% by mass, 3 to 15% by mass, 3 to 10% by mass, 5 to 70% by mass, 5 to 60% by mass, 5 to 50% by mass, 5 to 40% by mass, 5 to 30% by mass, 5 to 20% by mass, 5 to 15% by mass, or 5 to 10% by mass.

[0041] Examples of the aromatic monomer include Compounds having one aromatic ring such as benzyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-trimethylphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate (2-HPA), 2-(meth)acryloyloxyhexahydrophthalic acid, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalic acid, EO-modified phenol (meth)acrylate, EO-modified cresol (meth)acrylate, EO-modified nonylphenol (meth)acrylate, PO-modified nonylphenol (meth)acrylate, ethoxylated-o-phenylphenol (meth)acrylate, m-phenoxybenzyl (meth)acrylate, etc.; Compounds having two or more aromatic rings such as ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, bisphenol A epoxy di(meth)acrylate, etc.; etc. can be mentioned.

[0042] From the viewpoint of further reducing the moisture permeability of the cured body and further improving the reliability of the organic EL element, as the aromatic monomer, a compound having two or more aromatic rings is preferable. The radically polymerizable compound preferably contains at least one selected from the group consisting of ethoxylated-o-phenylphenol (meth)acrylate, m-phenoxybenzyl (meth)acrylate, and ethoxylated bisphenol A di(meth)acrylate as the aromatic monomer, and more preferably contains at least one selected from the group consisting of ethoxylated-o-phenylphenol (meth)acrylate and ethoxylated bisphenol A di(meth)acrylate.

[0043] The radically polymerizable compound preferably contains an acyclic monomer having a radically polymerizable group and no ring structure.

[0044] The number of radically polymerizable groups in the acyclic monomer may be, for example, 1 or more, preferably 2 or more. The number of radically polymerizable groups in the acyclic monomer may be, for example, 6 or less, preferably 4 or less, more preferably 3 or less. That is, the number of radically polymerizable groups in the acyclic monomer may be, for example, 1 to 6, 1 to 4, 1 to 3, 2 to 6, 2 to 4, or 2 to 3. The number of radically polymerizable groups in the acyclic monomer is particularly preferably 2.

[0045] Examples of the acyclic monomer include compounds having a radically polymerizable group and a chain saturated hydrocarbon group (hereinafter also referred to as a chain monomer).

[0046] The number of carbon atoms in the chain saturated hydrocarbon group of the chain monomer is, for example, 2 or more, and may be 3 or more, 4 or more, 6 or more, 8 or more, or 10 or more. The number of carbon atoms in the chain saturated hydrocarbon group of the chain monomer is, for example, 16 or less, and may be 15 or less, 14 or less, or 13 or less. That is, the number of carbon atoms in the chain saturated hydrocarbon group of the chain monomer may be, for example, 2 to 16, 2 to 15, 2 to 14, 2 to 13, 3 to 16, 3 to 15, 3 to 14, 3 to 13, 4 to 16, 4 to 15, 4 to 14, 4 to 13, 6 to 16, 6 to 15, 6 to 14, 6 to 13, 8 to 16, 8 to 15, 8 to 14, 8 to 13, 10 to 16, 10 to 15, 10 to 14, or 10 to 13.

[0047] The chain saturated hydrocarbon group of the chain monomer is preferably an alkanediyl group. The preferred range of the number of carbon atoms of the alkanediyl group is the same as the preferred range of the number of carbon atoms of the chain saturated hydrocarbon group.

[0048] When the radically polymerizable compound contains a chain monomer, the proportion of the chain monomer in the radically polymerizable compound may be, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, and may be 40% by mass or more, 50% by mass or more, or 55% by mass or more. Further, the proportion of the chain monomer in the radically polymerizable compound may be, for example, 90% by mass or less, preferably 85% by mass or less, more preferably 80% by mass or less, and may be 75% by mass or less. That is, the proportion of the chain monomer in the radically polymerizable compound may be, for example, 10 to 90% by mass, 10 to 85% by mass, 10 to 80% by mass, 10 to 75% by mass, 20 to 90% by mass, 20 to 85% by mass, 20 to 80% by mass, 20 to 75% by mass, 30 to 90% by mass, 30 to 85% by mass, 30 to 80% by mass, 30 to 75% by mass, 40 to 90% by mass, 40 to 85% by mass, 40 to 80% by mass, 40 to 75% by mass, 50 to 90% by mass, 50 to 85% by mass, 50 to 80% by mass, 50 to 75% by mass, 55 to 90% by mass, 55 to 85% by mass, 55 to 80% by mass, or 55 to 75% by mass.

[0049] Examples of the chain monomer include alkanediol di(meth)acrylates such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,13-tridecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,15-pentadecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate; polyethylene glycol di(meth)acrylates such as diethylene glycol di(meth)acrylate and triethylene glycol di(meth)acrylate; Polypropylene glycol di(meth)acrylate such as dipropylene glycol di(meth)acrylate and tripropylene glycol di(meth)acrylate; and the like.

[0050] The radically polymerizable compound preferably contains a compound having a fluoro group (hereinafter also referred to as a fluorine-containing monomer). Thereby, the surface free energy of the sealant becomes low, it becomes easy to follow minute unevenness, and the flatness of the coating film tends to be further improved.

[0051] When the radically polymerizable compound contains a fluorine-containing monomer, the proportion of the fluorine-containing monomer in the radically polymerizable compound may be, for example, 0.1% by mass or more, preferably 0.3% by mass or more, more preferably 0.5% by mass or more, and may be 0.7% by mass or more, 0.9% by mass or more, or 1% by mass or more. Further, the proportion of the fluorine-containing monomer in the radically polymerizable compound may be, for example, 15% by mass or less, preferably 10% by mass or less, and may be 7% by mass or less, 5% by mass or less, 3% by mass or less, or 2% by mass or less. That is, the proportion of the fluorine-containing monomer in the radically polymerizable compound may be, for example, 0.1 to 15% by mass, 0.1 to 10% by mass, 0.1 to 7% by mass, 0.1 to 5% by mass, 0.1 to 3% by mass, 0.1 to 2% by mass, 0.3 to 15% by mass, 0.3 to 10% by mass, 0.3 to 7% by mass, 0.3 to 5% by mass, 0.3 to 3% by mass, 0.3 to 2% by mass, 0.5 to 15% by mass, 0.5 to 10% by mass, 0.5 to 7% by mass, 0.5 to 5% by mass, 0.5 to 3% by mass, 0.5 to 2% by mass, 0.7 to 15% by mass, 0.7 to 10% by mass, 0.7 to 7% by mass, 0.7 to 5% by mass, 0.7 to 3% by mass, 0.7 to 2% by mass, 0.9 to 15% by mass, 0.9 to 10% by mass, 0.9 to 7% by mass, 0.9 to 5% by mass, 0.9 to 3% by mass, 0.9 to 2% by mass, 1 to 15% by mass, 1 to 10% by mass, 1 to 7% by mass, 1 to 5% by mass, 1 to 3% by mass, or 1 to 2% by mass.

[0052] The number of fluoro groups in the fluorine-containing monomer may be, for example, 1 or more, preferably 2 or more, and more preferably 3 or more. In addition, the number of fluoro groups in the fluorine-containing monomer is not particularly limited, but may be, for example, 40 or less, and preferably 30 or less. That is, the number of fluoro groups in the fluorine-containing monomer may be, for example, 1 to 40, 1 to 30, 2 to 40, 2 to 30, 3 to 40, or 3 to 30.

[0053] The content of fluorine atoms relative to the total amount of the fluorine-containing monomer may be, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 5% by mass or more. According to a fluorine-containing monomer that satisfies such a content range, the above-mentioned effects are more significantly exhibited. Furthermore, the content of fluorine atoms relative to the total amount of the fluorine-containing monomer may be, for example, 75% by mass or less, preferably 70% by mass or less, more preferably 65% ​​by mass or less. That is, the content of fluorine atoms relative to the total amount of the fluorine-containing monomer may be, for example, 1 to 75% by mass, 1 to 70% by mass, 1 to 65% by mass, 2 to 75% by mass, 2 to 70% by mass, 2 to 65% by mass, 5 to 75% by mass, 5 to 70% by mass, or 5 to 65% by mass.

[0054] The number of radical polymerizable groups in the fluorine-containing monomer may be 1 or more. From the viewpoint of easily obtaining a cured body having a low glass transition temperature, the number of radical polymerizable groups in the fluorine-containing monomer may be 1. From the viewpoint of easily obtaining a cured body having a high glass transition temperature, the number of radical polymerizable groups in the fluorine-containing monomer may be 2 or more. The upper limit of the number of radical polymerizable groups in the fluorine-containing monomer is not particularly limited. The number of radical polymerizable groups in the fluorine-containing monomer is, for example, 4 or less, and from the viewpoint of easily obtaining a cured body having excellent flexibility, it is preferably 3 or less, more preferably 2 or less.

[0055] Examples of the fluorine-containing monomer include 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, 1H,1H,2H,2H-tridecafluorooctyl (meth)acrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluoro-1,10-decanedi(meth)acrylate, and the like.

[0056] (Photoinitiator) The photoinitiator may be any initiator capable of polymerizing the above-mentioned radically polymerizable compound. The photoinitiator may be used alone or in combination of two or more.

[0057] Examples of the photoinitiator include Benzophenone and its derivatives; Benzyl and its derivatives; Anthraquinone and its derivatives; Benzoin type photoinitiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, benzyl dimethyl ketal; Acetophenone type photoinitiators such as diethoxyacetophenone, 4-tert-butyltrichloroacetophenone; 2-Dimethylaminoethyl benzoate; p-Dimethylaminoethyl benzoate; Diphenyl disulfide; Thioxanthone and its derivatives; Camphorquinone type photoinitiators such as camphorquinone, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-bromoethyl ester, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-methyl ester, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid chloride; α - aminoalkylphenone - type photoinitiators such as 2 - methyl - 1 - [4 - (methylthio)phenyl] - 2 - morpholinopropan - 1 - one, 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl) - butan - 1 - one; Acylphosphine oxide - type photoinitiators such as benzoyldiphenylphosphine oxide, 2,4,6 - trimethylbenzoyl - diphenyl - phosphine oxide, benzoyldiethoxyphosphine oxide, 2,4,6 - trimethylbenzoyldimethoxyphenylphosphine oxide, 2,4,6 - trimethylbenzoyldiethoxyphenylphosphine oxide, bis(2,4,6 - trimethylbenzoyl) - phenylphosphine oxide; Phenyl - glyoxylic acid - methyl ester; Oxy - phenyl - acetic acid 2 - [2 - oxo - 2 - phenyl - acetoxy - ethoxy] - ethyl ester; Oxy - phenyl - acetic acid 2 - [2 - hydroxy - ethoxy] - ethyl ester; etc. are included.

[0058] As the photoinitiator, an acylphosphine oxide - type photoinitiator is preferred because it can be cured using only visible light of 390 nm or more and can be cured without damaging the organic EL element. Among acylphosphine oxide - type photoinitiators, 2,4,6 - trimethylbenzoyl - diphenyl - phosphine oxide is preferred in terms of further improving the transparency of the cured product and being curable using only light of 395 nm or more. Examples of 2,4,6 - trimethylbenzoyl - diphenyl - phosphine oxide include "Omnirad TPO" manufactured by IGM Resins.

[0059] The content of the photopolymerization initiator may be, for example, 0.05 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and still more preferably 2 parts by mass or more with respect to 100 parts by mass of the radically polymerizable compound. Also, the content of the photopolymerization initiator may be, for example, 10 parts by mass or less, preferably 8 parts by mass or less, and more preferably 5 parts by mass or less with respect to 100 parts by mass of the radically polymerizable compound. With such a content, it tends to be easy to ensure sufficient transparency of the encapsulant while obtaining sufficient sensitivity and curing rate of the sealant. That is, the content of the photopolymerization initiator may be, for example, 0.05 to 10 parts by mass, 0.05 to 8 parts by mass, 0.05 to 5 parts by mass, 0.5 to 10 parts by mass, 0.5 to 8 parts by mass, 0.5 to 5 parts by mass, 1 to 10 parts by mass, 1 to 8 parts by mass, 1 to 5 parts by mass, 2 to 10 parts by mass, 2 to 8 parts by mass, or 2 to 5 parts by mass with respect to 100 parts by mass of the radically polymerizable compound.

[0060] (Stable radical type compound) The stable radical type compound is a compound having a stable radical. The photopolymerization initiator may be used alone or in combination of two or more.

[0061] As the stable radical, a nitroxide radical (NO radical) is preferable. That is, as the stable radical type compound, a compound having a nitroxide radical is preferable. Since the nitroxide radical is excellent in compatibility and reactivity with the radically polymerizable compound, it can quickly capture radical species.

[0062] In the manufacturing process of an organic EL display device, since the organic EL element deteriorates due to oxygen, it is managed at an oxygen concentration of less than 1 ppm, and the encapsulant for the organic EL element is also used at a low oxygen concentration. Here, general phenolic antioxidants used for suppressing the polymerization of radically polymerizable compounds require reaction with oxygen in the process of exerting the polymerization suppression function. For this reason, it is difficult for phenolic antioxidants to exert the polymerization suppression function in the encapsulant for organic EL elements. On the other hand, stable radical type compounds having stable radicals (especially nitroxide radicals) can capture radical species regardless of the presence or absence of oxygen, so the above-described effects can be obtained remarkably.

[0063] Examples of the stable radical type compound include 1-oxyl-2,2,6,6-tetramethylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl, etc. From the viewpoint of being incorporated into the cured body and being less likely to become outgas, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl is preferable, and 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl is more preferable.

[0064] The content of the stable radical type compound may be, for example, 1 mass ppm or more, preferably 10 mass ppm or more, more preferably 50 mass ppm or more, still more preferably 100 mass ppm or more, with respect to 100 parts by mass of the radically polymerizable compound. Also, the content of the stable radical type compound may be, for example, 15000 mass ppm or less, preferably 10000 mass ppm or less, more preferably 8000 mass ppm or less, still more preferably 6000 mass ppm or less, with respect to 100 parts by mass of the radically polymerizable compound. By using an appropriate amount of the stable radical type compound, the above-described effects are more remarkably exhibited. That is, the content of the stable radical type compound may be, for example, 1 to 15,000 mass ppm, 1 to 10,000 mass ppm, 1 to 8,000 mass ppm, 1 to 6,000 mass ppm, 10 to 15,000 mass ppm, 10 to 10,000 mass ppm, 10 to 8,000 mass ppm, 10 to 6,000 mass ppm, 50 to 15,000 mass ppm, 50 to 10,000 mass ppm, 50 to 8,000 mass ppm, 50 to 6,000 mass ppm, 100 to 15,000 mass ppm, 100 to 10,000 mass ppm, 100 to 8,000 mass ppm, or 100 to 6,000 mass ppm with respect to 100 parts by mass of the radically polymerizable compound.

[0065] (Other components) The encapsulant of the present embodiment may further contain other components other than those described above. Examples of other components include antioxidants, surfactants, sensitizers, and the like.

[0066] The content of other components is not particularly limited, and may be, for example, 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 3 parts by mass or less, 2 parts by mass or less, or 1 part by mass or less with respect to 100 parts by mass of the radically polymerizable compound.

[0067] The viscosity of the encapsulant of the present embodiment is preferably 3 mPa·s or more, more preferably 5 mPa·s or more. Also, the viscosity of the encapsulant of the present embodiment is preferably 50 mPa·s or less, more preferably 30 mPa·s or less. When the viscosity of the encapsulant is within the above range, the dischargeability during coating by the inkjet method tends to be more improved, and film formation tends to be easier. That is, the viscosity of the encapsulant of the present embodiment may be, for example, 3 to 50 mPa·s, 3 to 30 mPa·s, 5 to 50 mPa·s, or 5 to 30 mPa·s.

[0068] In this specification, the viscosity of the encapsulant indicates a value measured under the conditions of 25°C and 250 rpm using a cone plate type viscometer (manufactured by Eiko Seiki Co., Ltd., product number: HB DV3T, etc.).

[0069] The sulfur atom concentration of the encapsulant of the present embodiment may be, for example, 100 ppm or less, preferably 50 ppm or less, and more preferably 40 ppm or more. The sulfur atom concentration of the encapsulant of the present embodiment may also be, for example, 0.1 ppm or more, or may be 1 ppm or more. With such a sulfur atom concentration, the deterioration of the organic EL element and the generation of dark spots are more significantly suppressed, and the reliability tends to be further improved. That is, the sulfur atom concentration of the encapsulant of the present embodiment may be, for example, 0.1 to 100 ppm, 0.1 to 50 ppm, 0.1 to 40 ppm, 1 to 100 ppm, 1 to 50 ppm, or 1 to 40 ppm.

[0070] Let the number of particles with a diameter of 1 μm or more present in 1 mL of the encapsulant of the present embodiment be a, and the number of particles with a diameter of 1 μm or more present in 1 mL of the encapsulant after heating at 80°C for 16 hours be b. Then, b - a is preferably 10 or less. According to such an encapsulant, coating defects caused by particles are suppressed, and excellent dischargeability from the coating device and high flatness of the coating film after coating are realized.

[0071] The above a is preferably 10 or less, more preferably 5 or less, still more preferably 3 or less, and may be 0.

[0072] The above b is preferably 10 or less, more preferably 5 or less, still more preferably 3 or less, and may be 0.

[0073] The encapsulant of the present embodiment may contain particles with a diameter of 1 μm or more, but preferably does not contain them (that is, a is 0). Examples of the particles include particles derived from polymers of radically polymerizable compounds, particles derived from foreign matters such as dust and dirt, and particles derived from dehydrating agents such as molecular sieves used in the manufacturing process of the encapsulant. The encapsulant of the present embodiment may be one in which particles are removed with a filtration filter or the like so as to substantially not contain these particles.

[0074] In the present specification, the number of particles indicates a value measured using a particle counter (manufactured by Rion Co., Ltd., light scattering type liquid particle detector, product number: KS-42B).

[0075] By curing the encapsulant of the present embodiment, a cured body containing a polymer of a radically polymerizable compound can be obtained. This cured body may contain stable radicals as a stable radical type compound or its reaction product. This cured body can be suitably used as an encapsulating material for organic EL elements.

[0076] The encapsulant of the present embodiment can be cured by light irradiation. The light source used for curing the encapsulant of the present embodiment is not particularly limited. Examples of the light source include a halogen lamp, a metal halide lamp, a high-power metal halide lamp (containing indium, etc.), a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a xenon excimer lamp, a xenon flash lamp, an LED, and the like.

[0077] The above light sources each have different emission wavelengths and energy distributions. Therefore, the above light sources may be appropriately selected according to the reaction wavelength of the photoinitiator and the like. Also, natural light (sunlight) can also be a reaction initiation light source.

[0078] Irradiation by the light source may be direct irradiation or may be condensing irradiation using a reflecting mirror, a fiber, or the like. Also, irradiation using a low-wavelength cut filter, a heat ray cut filter, a cold mirror, or the like may be used.

[0079] Examples of the method for encapsulating an organic EL element using the encapsulant of the present embodiment include the following encapsulation methods and the like.

[0080] · Encapsulation method Prepare a substrate on which an organic EL element is installed, apply an encapsulant on the surface of the substrate where the organic EL element is installed to form a coating film of the encapsulant. Then, irradiate the coating film with light to form an encapsulating material made of a cured body of the encapsulant. Thereby, the organic EL element is encapsulated with the encapsulating material.

[0081] For the application of the sealing agent, it is preferable to adopt an inkjet method. In the manufacture of an organic EL display device, it is necessary to apply a sealing agent onto a large-area substrate on which a plurality of organic EL elements are installed. Since the sealing agent of the present embodiment can be applied while maintaining high ejection performance even in the case of the inkjet method, a uniform coating film can be formed on a large-area substrate.

[0082] The film thickness of the coating film of the sealing agent may be, for example, 1 μm or more, preferably 3 μm or more. Thereby, it becomes easy to form a sealing material having sufficient sealing ability. Further, the film thickness of the coating film of the sealing agent may be, for example, 10 μm or less, preferably 9 μm or less. Thereby, miniaturization of the organic EL display device, reduction of manufacturing costs, etc. are expected. That is, the film thickness of the coating film of the sealing agent may be, for example, 1 to 10 μm, 1 to 9 μm, 3 to 10 μm, or 3 to 9 μm.

[0083] As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to the above embodiments. For example, the present invention can adopt various configurations other than the above. Further, the present invention may be a modification, improvement, etc. of the above embodiment within the range that can achieve the object of the present invention.

[0084] For example, the present invention may relate to an organic EL display device including an organic EL element and a sealing material for sealing the organic EL element. The sealing material includes a cured product of the above-described sealing agent. In this organic EL display device, the organic EL element may be a known organic EL element. Further, the configurations other than the organic EL element and the sealing material may be the same as those of a known organic EL display device.

Examples

[0085] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0086] In the examples and comparative examples, the following components were used. (A) Radical polymerizable compound (A-1) SR262 (1,12-dodecanediol dimethacrylate, manufactured by Arkema) (chain monomer) (A-2) BPE200 (ethoxylated bisphenol A dimethacrylate (compound represented by the following formula (m + n = 4), manufactured by Shin-Nakamura Chemical Co., Ltd.) (aromatic monomer) [Chemical formula] (A-3) LINC-162A (2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluoro-1,10-decane diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.) (fluorine-containing monomer) (A-4) FA-512AS (dicyclopentenyl oxyethyl acrylate, manufactured by Showa Denko Materials Co., Ltd.) (unsaturated alicyclic monomer) (A-5) IBXA (isobornyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0087] (B) Polymerization initiator (B-1) TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by IGM Resins)

[0088] (C) Stable radical type compound (C-1) TEMPO methacrylate (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0089] In the examples and comparative examples, the following measurements and evaluations were performed.

[0090] (Unreacted monomer concentration) The sealant was sandwiched between PET films with a 100 μm spacer tape attached, and irradiated with an LED lamp (HOYA UV-LED LIGHT SOURCE H-4MLH200-V1) that emits light with a wavelength of 395 nm, with an integrated light amount of 1,500 mJ / cm 2Light with a wavelength of 395 nm was irradiated so as to obtain the following. The cured film obtained was peeled off from the PET film, cut into 5 mm squares, and 0.5 g was weighed into a 10 mL vial. 5 mL of acetone was injected into the vial, ultrasonic treatment was applied for 30 minutes, and it was left standing in an atmosphere of 23 °C for 16 hours. After standing, it was filtered through a 0.45 μm membrane filter and measured by gas chromatography, and the concentration of the unreacted monomer was quantified from the peak area of the obtained chart. The specifications of the gas chromatography can be determined as appropriate, and for example, the following can be adopted. · Equipment: Agilent 7890B · Column: HP-5MS 60 m × φ0.25 mm × film thickness 0.25 μm · Column Temp.: 40 °C for 1 min, then the temperature was raised to 180 °C at a heating rate of 20 °C / min, and then the temperature was raised to 300 °C at a heating rate of 10 °C / min and held for 50 min · Inj. Temp.: 300 °C · Det. Temp.: 300 °C · Flow: 1 mL / min × 22 min, then 0.1 mL / min, then 2 mL / min, split 1 / 20 · Inj: 1 μL

[0091] (Reliability Evaluation of Organic EL Display Device (Organic EL Reliability)) · Fabrication of Organic EL Display Device for Evaluation A glass substrate (thickness 700 μm) with a 30 mm square ITO electrode was cleaned using acetone and isopropanol respectively. Then, the following compounds were sequentially vapor-deposited into thin films by vacuum vapor deposition to obtain a substrate having a 2 mm square organic EL element composed of anode / hole injection layer / hole transport layer / light-emitting layer / Hole Blocking layer / electron transport layer / electron injection layer / cathode. The composition of each layer is as follows. Anode (ITO): 150 nm Hole Injection Layer (Polymer HIL): 60 nm Hole Transport Layer (α-NPD): 30 nm Light-Emitting Layer (Ir(ppy)3 + CBP[6%]): 30 nm Hole Blocking Layer (BAlq): 10 nm Electron transport layer (Alq3): 30 nm Electron injection layer (LiF): 0.8 nm Cathode (MgAg / IZO): 10 nm / 100 nm ITO is indium tin oxide, HIL is Hole Injection Layer, α-NPD is N,N’-diphenyl-N,N’-dinaphthylbenzidine, Ir(ppy)3 is an iridium complex [tris(2-phenylpyridine)iridium], CBP is 4,4’-N,N’-dicarbazole-biphenyl, BAlq is bis(2-methyl-8-quinolinolato)(p-phenylphenolato)aluminum, Alq3 is tris(8-hydroxyquinolinolato)aluminum, LiF is lithium fluoride, and IZO is indium zinc oxide. Next, under a nitrogen atmosphere, a sealing agent was dropped using an inkjet device (product number: DMP2850) manufactured by Fujifilm to cover a 2 mm × 2 mm organic EL element, and a coating film with a thickness of 10 μm was obtained. Then, under a nitrogen atmosphere, a LED lamp (HOYA UV-LED LIGHT SOURCE H-4MLH200-V1) that emits light with a wavelength of 395 nm was used to irradiate the coating film so that the integrated light quantity became 1,500 mJ / cm 2 Thereby, a cured film was obtained. A mask (cover) having an opening of 10 mm × 10 mm was installed so as to cover the entire obtained cured film, and a SiN film was formed by plasma CVD method. The thickness of the formed SiN (inorganic film) was about 1 μm. Thereby, a seal for the organic EL element was obtained. The obtained seal was bonded to a 30 mm × 30 mm × 0.7 mmt non-alkali glass (Eagle XG manufactured by Corning) using a 30 mm × 30 mm × 25 μmt transparent base material-less double-sided tape. Thereby, an organic EL display device for evaluation was manufactured. ·Reliability test The organic EL display device for evaluation was left standing in a high-temperature and high-humidity environment of 85°C and 85% RH for 500 hours. Before and after this high-temperature and high-humidity treatment, an electric current was passed through the organic EL display device for evaluation, and the light-emitting surface was photographed. The photographed images (the image before the high-temperature and high-humidity treatment and the image after the high-temperature and high-humidity treatment) were analyzed using the image analysis software "Quick Grain" from Inotech to determine the light-emitting area. Then, the reduction rate (%) of the light-emitting area before and after the high-temperature and high-humidity treatment was calculated.

[0092] (Examples 1 to 4) Each component was mixed with the composition shown in Table 1 to produce a sealing agent. The obtained sealing agent was subjected to the above measurements and evaluations. The results are shown in Table 1.

[0093] (Comparative Examples 1 to 3) Each component was mixed with the composition shown in Table 2 to produce a sealing agent. The obtained sealing agent was subjected to the above measurements and evaluations. The results are shown in Table 2.

[0094]

Table 1

[0095]

Table 2

[0096] As shown in Tables 1 and 2, the sealing agents of Examples 1 to 4 had a significantly lower unreacted monomer concentration compared to the sealing agents of the comparative examples. In addition, the organic EL display devices in which the organic EL elements were sealed with the sealing agents of Examples 1 to 4 were confirmed to have significantly suppressed the generation of dark spots and significantly improved reliability compared to the organic EL display devices in which the organic EL elements were sealed with the sealing agents of the comparative examples.

Claims

1. A sealing agent for an organic electroluminescence device, comprising a radically polymerizable compound, a photopolymerization initiator, and a stable radical type compound having a stable radical. The radically polymerizable compound includes an unsaturated alicyclic monomer having a radically polymerizable group and an unsaturated aliphatic hydrocarbon ring. The stable radical type compound includes 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl. A sealing agent for an organic electroluminescence device.

2. The sealing agent according to Claim 1, wherein the unsaturated aliphatic hydrocarbon ring is a cycloalkene ring.

3. The sealing agent according to Claim 1, wherein the content of the unsaturated alicyclic monomer is 3 to 90% by mass based on the total amount of the radically polymerizable compound.

4. The sealing agent according to Claim 1, wherein the content of the stable radical type compound is 1 to 15000 mass ppm with respect to 100 parts by mass of the radically polymerizable compound.

5. The sealing agent according to Claim 1, wherein the radically polymerizable compound further includes an acyclic monomer having a radically polymerizable group and no ring structure.

6. The sealing agent according to Claim 1, wherein the radically polymerizable compound further includes an aromatic monomer having a radically polymerizable group and an aromatic ring.

7. The sealing agent according to Claim 1, wherein the radically polymerizable compound further includes a fluorine-containing monomer having a radically polymerizable group and a fluorine group.

8. A sealing material including a cured product of the sealing agent according to any one of Claims 1 to 7.

9. An organic electroluminescence device, and the sealing material according to Claim 8 for sealing the organic electroluminescence device. An organic electroluminescence display device comprising the above.

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