Sealant for display element, cured product thereof, and display device

Abstract

The present invention provides a sealant for display elements, which contains component (A), component (B) and component (C). Component (A): a polymerizable compound; component (B): a polymerization initiator; component (C): an antioxidant. The glass transition temperature of the cured product of the sealant for display elements is 90 °C or higher and less than 200 °C.

Description

Technical Field

[0001] The present invention relates to a sealant for display elements, a cured product thereof, and a display device. Background Art

[0002] In the field of display elements, research has been continuously conducted to improve the properties of sealants. Hereinafter, an organic EL display device will be exemplified for explanation.

[0003] Since organic EL elements consume less power, they are gradually used in displays, lighting devices, etc. Organic EL elements are liable to deteriorate due to moisture and oxygen in the atmosphere, so they are used after being sealed with various sealing members. For practical use, it is desired to improve the durability of various sealing members against moisture and oxygen.

[0004] As a sealing method for organic EL elements, for example, the following method is adopted: a first layer of an inorganic material film is coated on the organic EL element and a resin layer is formed thereon, and then a second layer of an inorganic material film is coated. As a method of coating using the above inorganic material film, for example, a method of forming an inorganic material film composed of silicon nitride, silicon oxide, etc. by a sputtering method, an electron cyclotron resonance (ECR) plasma CVD method, etc. can be cited.

[0005] In Patent Document 1 (International Publication No. 2018 / 70488), as a technique for providing a composition excellent in coatability and low moisture permeability for use in sealing organic EL elements, a composition containing a specific amount of a specific (meth)acrylate is proposed. In the same document, it is described that "if the glass transition temperature of the cured product obtained from the composition is 200°C or higher, when an inorganic passivation film is formed on the cured product of the composition of the present embodiment by a method such as CVD, pinholes caused by uneven film formation of the inorganic passivation film due to thermal expansion will not occur, and the reliability of the organic EL element will be improved" (paragraph 0089).

[0006] The object of Patent Document 2 (Japanese Patent Application Laid-Open No. 2017-523549) is to provide an organic barrier layer excellent in plasma resistance and a composition for sealing an organic light-emitting element capable of improving the reliability of the organic light-emitting element.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: International Publication No. 2018 / 070488

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-523549 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] The inventors of the present invention studied the technologies described in the above patent documents, and the results are as follows: In Patent Document 1, since the glass transition temperature of the solidified product is high, it is expected that there will be cases where it is not suitable for devices that require flexibility, and there is room for improvement in this regard.

[0013] In addition, in the technology described in Patent Document 2, since the sealing composition contains a silicone-based di(meth)acrylate having a specific skeleton, the glass transition temperature is high, and it is expected that there will still be cases where it is not suitable for devices that require flexibility, and there is room for improvement in this regard.

[0014] The present invention provides a sealant for a display element that can form a resin layer having excellent plasma resistance and high flexibility.

[0015] Method for solving the problem

[0016] According to the present invention, there are provided a sealant for a display element, a solidified product, and a display device as shown below.

[0017] [1] A sealant for a display element, which contains the following components (A) to (C):

[0018] (A) A polymerizable compound,

[0019] (B) A polymerization initiator,

[0020] (C) An antioxidant,

[0021] The glass transition temperature of the solidified product of the sealant for a display element is 90 °C or higher and less than 200 °C.

[0022] [2] The sealant for a display element according to [1], wherein the aforementioned component (C) is a hindered phenol compound.

[0023] [3] The sealant for a display element according to [1] or [2], wherein the aforementioned component (C) is at least one of dibutylhydroxytoluene and pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0024] [4] The sealant for a display element according to any one of [1] to [3], wherein the aforementioned component (A) is a compound containing a (meth)acryloyl group.

[0025] [5] The sealant for a display element according to any one of [1] to [4], which is used for sealing an organic EL display element.

[0026] [6] A solidified product, which is obtained by solidifying the sealant for a display element according to any one of [1] to [5].

[0027] [7]A display device includes: a substrate, a display element disposed on the substrate, and a sealing layer covering the display element.

[0028] The sealing layer is composed of a cured product of the sealing agent for a display element described in any one of [1] to [5].

[0029] Advantageous Effects of the Invention

[0030] According to the present invention, it is possible to provide a sealing agent for a display element that can form a resin layer having excellent plasma resistance and high flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a cross-sectional view showing a configuration example of an organic EL display device in an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that in all the drawings, the same components are given common reference numerals, and the description will be appropriately omitted. In addition, in the present embodiment, for each component, one type may be used alone, or two or more types may be used in combination. In addition, "~" indicating a numerical range means above and below, including both the upper limit value and the lower limit value.

[0033] (Sealing Agent for Display Element)

[0034] In the present embodiment, the sealing agent for a display element (hereinafter, sometimes simply referred to as "sealing agent") is a composition for element sealing, and includes the following components (A) to (C), and the glass transition temperature of the cured product is 90°C or higher and less than 200°C.

[0035] (A) Polymerizable Compound

[0036] (B) Polymerization Initiator

[0037] (C) Antioxidant

[0038] First, specific examples will be given to describe the constituent components of the sealing agent.

[0039] (Component (A))

[0040] Component (A) is a polymerizable compound. Component (A) may be any compound having a polymerizable functional group, and is preferably a compound having a radical polymerizable functional group.

[0041] Specific examples of the radical polymerizable functional group include one or more groups selected from the group consisting of (meth)acryloyl and vinyl. From the viewpoint of improving curability, component (A) is preferably a compound containing (meth)acryloyl. ​

[0042] Here, in this specification, the term "(meth)acryloyl" means at least one of acryloyl and methacryloyl. Further, the term "(meth)acrylic acid" means at least one of acrylic acid and methacrylic acid. Further, the term "(meth)acrylate" means at least one of acrylate and methacrylate.

[0043] Specific examples of the (meth)acrylic acid-based compound having a (meth)acryloyl group include mono(meth)acrylic acid-based compounds, di(meth)acrylic acid-based compounds, and (meth)acrylic acid-based compounds having 3 or more functional groups.

[0044] Specific examples of the mono(meth)acrylic acid compound include isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydixyl ethyl (meth)acrylate, ethyl diethylene glycol (meth)acrylate, cyclic trimethylolpropane formal mono(meth)acrylate, imide (meth)acrylate, isopentyl (meth)acrylate, ethoxylated succinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, ω-carboxypolycaprolactone mono(meth)acrylate, cyclohexyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, stearyl (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, lauryl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, octyl / decyl (meth)acrylate, tridecyl (meth)acrylate, caprolactone (meth)acrylate, ethoxylated (4) nonylphenol (meth)acrylate, methoxypolyethylene glycol (350) mono(meth)acrylate, methoxypolyethylene glycol (550) mono(meth)acrylate, phenoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, tribromophenyl (meth)acrylate, ethoxylated tribromophenyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, ethylene oxide adduct of 2-phenoxyethyl (meth)acrylate, propylene oxide adduct of 2-phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-methacryloxymethyl cyclohexene oxide, and 3-(meth)acryloxymethyl cyclohexene oxide, etc.

[0045] As specific examples of the bis(meth)acrylic acid compounds, di(meth)acrylates of diols and di(meth)acrylates of (poly)alkylene glycols can be mentioned. More specifically, examples include: 1,6-hexanediol diacrylate (e.g., A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,9-nonanediol diacrylate (e.g., A-NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,9ND-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,10-decanediol diacrylate (e.g., A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), neopentyl glycol diacrylate (e.g., A-NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate NP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethylene glycol diacrylate (e.g., SR206NS, manufactured by Arkema), polyethylene glycol diacrylate (e.g., A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), polypropylene glycol diacrylate (e.g., APG-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), tricyclodecane dimethanol diacrylate (dihydroxymethyl tricyclodecane diacrylate) (e.g., A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.; LightAcrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,3-butanediol dimethacrylate (e.g., BG, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,4-butanediol dimethacrylate (e.g., BD, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,6-hexanediol dimethacrylate (e.g., HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,9-nonanediol dimethacrylate (e.g., NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,10-decanediol dimethacrylate (e.g., DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,12-dodecanediol diacrylate (e.g., SR262, manufactured by Sartomer), neopentyl glycol dimethacrylate (e.g., NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0046] As specific examples of the polyfunctional (meth)acrylic acid compounds having 3 or more functional groups, examples include trifunctional (meth)acrylic acid compounds such as trimethylolpropane triacrylate (e.g., A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate TMP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethoxylated trimethylolpropane triacrylate (e.g., A-TMPT-EO, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated glycerol triacrylate (e.g., A-GLY-6E, manufactured by Shin-Nakamura Chemical Co., Ltd.), propoxylated glycerol triacrylate (e.g., A-GLY-3P, manufactured by Shin-Nakamura Chemical Co., Ltd.);

[0047] 4-functional (meth)acrylic compounds such as pentaerythritol tetraacrylate (e.g., A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated pentaerythritol tetraacrylate (e.g., ATM-4E, manufactured by Shin-Nakamura Chemical Co., Ltd.), ditrimethylolpropane tetraacrylate (e.g., AD-TMP-L, manufactured by Shin-Nakamura Chemical Co., Ltd.);

[0048] 5-functional (meth)acrylate compounds such as dipentaerythritol pentaacrylate (e.g., M-402, manufactured by Toagosei Co., Ltd.); and

[0049] 6-functional (meth)acrylic compounds such as dipentaerythritol hexaacrylate (e.g., GM66G0H, manufactured by Kokusaku Chemical Co., Ltd.).

[0050] From the viewpoint of improving the durability during long-term use of a display device, such as an organic EL display device, component (A) preferably contains a (meth)acrylic compound having two or more (meth)acryloyl groups in one molecule, more preferably contains a di(meth)acrylic compound, and further preferably contains a di(meth)acrylic compound having an alicyclic structure and a di(meth)acrylic compound having a chain structure.

[0051] The di(meth)acrylic compound having an alicyclic structure has an alicyclic hydrocarbon structure in its molecular structure. From the viewpoint of improving heat resistance, the number of carbon atoms in the alicyclic hydrocarbon structure is preferably 4 or more, more preferably 5 or more, further preferably 6 or more, and additionally preferably 14 or less, more preferably 12 or less, and further preferably 10 or less.

[0052] The alicyclic hydrocarbon structure can be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure. From the viewpoint of improving heat resistance, the alicyclic hydrocarbon structure is preferably a saturated hydrocarbon structure.

[0053] In addition, the alicyclic hydrocarbon structure can be a monocyclic hydrocarbon structure, or a polycyclic hydrocarbon structure such as a fused-ring hydrocarbon structure or a bridged-ring hydrocarbon structure. The di(meth)acrylic compound having an alicyclic structure may contain a group having such an alicyclic hydrocarbon structure in its molecular structure, and preferably contains a divalent group having an alicyclic hydrocarbon structure.

[0054] Specific examples of the monocyclic hydrocarbon group include: groups having a cycloalkane structure such as cyclohexylene and cyclohexyl; groups having a cycloolefin skeleton such as cyclodecatrienediyl and cyclodecatrienyl.

[0055] Specific examples of the polycyclic hydrocarbon group include: groups having a dicyclopentadiene skeleton such as tricyclodecanediyl, dicyclopentyl, and dicyclopentenyl; groups having a norbornane skeleton such as norbornanediyl, isobornanediyl, norbornyl, and isobornyl; groups having an adamantane skeleton such as adamantanediyl and adamantyl, etc.

[0056] From the viewpoints of improving plasma resistance and low moisture permeability, the cyclic hydrocarbon group in the dicycloalkylene (meth)acrylate compound having an alicyclic structure is preferably a group having a dicyclopentadiene skeleton.

[0057] In addition, from the viewpoints of improving plasma resistance and low moisture permeability, the dicycloalkylene (meth)acrylate compound having an alicyclic structure contains tricyclodecane dimethanol di(meth)acrylate, and more preferably, the dicycloalkylene (meth)acrylate compound having an alicyclic structure is tricyclodecane dimethanol di(meth)acrylate.

[0058] From the viewpoint of improving heat resistance, the content of the dicycloalkylene (meth)acrylate compound having an alicyclic structure in the sealant is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, further preferably 15 parts by mass or more, still further preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and further preferably 30 parts by mass or more with respect to 100 parts by mass of the polymerizable compound.

[0059] In addition, from the viewpoint of making the inkjet coatability better, the content of the dicycloalkylene (meth)acrylate compound having an alicyclic structure in the sealant is preferably 60 parts by mass or less, more preferably 58 parts by mass or less, further preferably 56 parts by mass or less, and still further preferably 50 parts by mass or less with respect to 100 parts by mass of the polymerizable compound.

[0060] Specifically, the dicycloalkylene (meth)acrylate compound having a chain structure is a (meth)acrylate having a chain structure in the molecular structure and having two or more (meth)acryloyl groups, and from the viewpoint of improving strength, it is preferably a (meth)acrylate having two (meth)acryloyl groups.

[0061] In the dicycloalkylene (meth)acrylate compound having a chain structure, the chain structure may be a straight-chain structure or a branched structure.

[0062] From the viewpoint of making the inkjet coatability better, the chain structure preferably contains a divalent hydrocarbon group having a straight chain or a branch. From the viewpoint of ease of obtaining the monomer, the number of carbon atoms of the divalent hydrocarbon group is, for example, 1 or more, preferably 2 or more, and more preferably 4 or more. In addition, from the viewpoint of improving heat resistance, the number of carbon atoms of the divalent hydrocarbon group is preferably 20 or less, and more preferably 14 or less.

[0063] As specific examples of the bis(meth)acrylic acid-based compound having a chain structure, alkylene glycol bis(meth)acrylate and (poly)alkylene glycol bis(meth)acrylate can be mentioned. Preferably, it is one or more compounds selected from the group consisting of alkylene glycol bis(meth)acrylate and (poly)alkylene glycol bis(meth)acrylate among the specific examples of the bis(meth)acrylic acid-based compound described above.

[0064] From the viewpoint of improving the balance of plasma resistance, coating stability in the inkjet method, and the effect of low dielectric constant, the bis(meth)acrylic acid-based compound having a chain structure is one or more (meth)acrylates selected from the group consisting of 1,9-nonanediol bis(meth)acrylate and neopentyl glycol bis(meth)acrylate.

[0065] From the viewpoint of making the inkjet coatability better, the content of the bis(meth)acrylic acid-based compound having a chain structure in the sealant is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, further preferably 15 parts by mass or more, further more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more with respect to 100 parts by mass of the polymerizable compound.

[0066] In addition, from the viewpoint of improving plasma resistance, the content of the bis(meth)acrylic acid-based compound having a chain structure in the sealant is preferably 60 parts by mass or less, more preferably 58 parts by mass or less, further preferably 56 parts by mass or less, further more preferably 50 parts by mass or less with respect to 100 parts by mass of the polymerizable compound.

[0067] From the viewpoint of improving the strength of the cured product, the content of component (A) in the sealant is preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 85% by mass or more, further more preferably 90% by mass or more, and even more preferably 93% by mass or more with respect to the total composition of the sealant.

[0068] In addition, from the viewpoint of improving the weather resistance of the sealing material, the content of component (A) in the sealant is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, further preferably 99% by mass or less, and even more preferably 98% by mass or less with respect to the total composition of the sealant.

[0069] (Component (B))

[0070] Component (B) is a polymerization initiator. From the viewpoint of stably forming a cured product at low temperatures, component (B) is preferably a photoinitiator, that is, a compound that generates free radicals or acids upon irradiation with ultraviolet or visible light. Examples of photoinitiators include acylphosphine oxide initiators, oxy phenylacetate initiators, benzoylformic acid initiators, and hydroxy phenyl ketone initiators.

[0071] Specific examples of photoinitiators include: benzophenone, Michler's ketone, 4,4'-bis(diethylamino)benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, ethyl 4-dimethylaminobenzoate, isopentyl 4-dimethylaminobenzoate, 4,4'-bis(tert-butylperoxycarbonyl)benzophenone, 3,4,4'-tris(tert-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetrakis(tert-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetrakis(tert-hexyloxycarbonyl)benzophenone, 3,3'-bis(methoxycarbonyl)-4,4'-bis(tert-butylperoxycarbonyl)benzophenone, 3,4'-bis(methoxycarbonyl)-4,3'-bis(tert-butylperoxycarbonyl)benzophenone, 4,4'-bis(methoxycarbonyl)-3,3'-bis(tert-butylperoxycarbonyl)benzophenone, 2-(4'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-pentyloxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 4-[p-N,N-bis(ethoxycarbonylmethyl)]-2,6-bis(trichloromethyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(4'-methoxyphenyl)-s-triazine, 2-(p-dimethylaminostyryl)benzo Oxazoles, 2-(p-dimethylaminostyryl)benzothiazole, 2-mercaptobenzothiazole, 3,3'-carbonylbis(7-diethylaminocoumarin), 2-(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetrakis(4-ethoxycarbonylphenyl)-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dibromophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 3-(2-methyl-2-dimethylaminopropionyl)carbazole, 3,6-bis(2-methyl-2-morpholinopropionyl)-9-n-dodecylcarbazole, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-1-propanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, hydroxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester, hydroxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, methyl benzoylformate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphate, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime)], 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone-1-(O-acetyl oxime), etc.

[0072] Among them, from the viewpoint of improving curability, the photoinitiator is preferably one or more compounds selected from the group consisting of the following compounds: 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-1-propanone, 2,2-dimethoxy-2-phenylacetophenone, 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl hydroxy-phenyl-acetate, 2-[2-hydroxy-ethoxy]-ethyl hydroxy-phenyl-acetate, methyl benzoylformate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and 2,4,6-trimethylbenzoyldiphenylphosphate.

[0073] As commercially available products of the photoinitiator, Irgacure 184, Irgacure 651, Irgacure 127, Irgacure 1173, Irgacure 500, Irgacure 2959, Irgacure 754, Irgacure MBF, Irgacure TPO (manufactured by BASF above), Omnirad TPO H (manufactured by IGM Resins), etc. are preferred.

[0074] From the viewpoint of improving curability, the content of component (B) in the sealant is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and still more preferably 2% by mass or more, based on the total composition of the sealant.

[0075] In addition, from the viewpoint of suppressing the coloring of the sealant, the content of component (B) in the sealant is preferably 10% by mass or less, more preferably 8% by mass or less, further preferably 6% by mass or less, and still more preferably 5% by mass or less, based on the total composition of the sealant.

[0076] (Component (C))

[0077] Component (C) is an antioxidant. Specific examples of the antioxidant include hindered phenol-based antioxidants and phosphorus-based antioxidants. Among them, from the viewpoint of improving plasma resistance, hindered phenol-based antioxidants are preferred, and more specifically, hindered phenol compounds are further preferred. Hindered phenol-based antioxidants are substances having a phenolic hydroxyl group that accepts free radicals generated in the reaction with oxygen and transforms into stable phenoxy radicals.

[0078] Examples of the hindered phenol compound include 2,6-bis(1,1-dimethylethyl)-4-methylphenol (manufactured by Wako Pure Chemical Industries, Ltd., BHT), 3,5-di-tert-butyl-4-hydroxytoluene, pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF, trade name IRGANOX1010; manufactured by ADEKA Corporation, AO-60), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (manufactured by BASF, trade name IRGANOX1076), etc.

[0079] Examples of the phosphorus-based antioxidant include phosphites such as 2,2-methylenebis(4,6-di-tert-butylphenyl) octyl phosphite (manufactured by ADEKA Corporation; trade name: Adekastab HP-10), tris(2,4-di-tert-butylphenyl) phosphite (manufactured by BASF; trade name: IRGAFOS168).

[0080] From the viewpoint of improving the flexibility and plasma resistance of the sealing material, component (C) is at least one of 2,6-bis(1,1-dimethylethyl)-4-methylphenol and pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0081] From the viewpoint of improving the flexibility of the sealing material, the content of component (C) in the sealant is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, and still more preferably 0.3% by mass or more based on the total composition of the sealant.

[0082] In addition, from the viewpoint of improving the curability of the sealing material, the content of component (C) in the sealant is preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.8% by mass or less, and still more preferably 0.6% by mass or less based on the total composition of the sealant.

[0083] Regarding the amount ratio of component (C) to component (A), from the viewpoint of improving the flexibility of the sealing material, the content of component (C) in the sealant is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, still more preferably 0.2 part by mass or more, and still more preferably 0.3 part by mass or more based on 100 parts by mass of component (A).

[0084] In addition, from the viewpoint of improving the curability of the sealing material, the content of component (C) in the sealant is preferably 2 parts by mass or less, more preferably 1 part by mass or less, still more preferably 0.8 part by mass or less, and still more preferably 0.6 part by mass or less based on 100 parts by mass of component (A).

[0085] In this embodiment, the sealant may be composed of components (A) to (C), or may contain components other than components (A) to (C). For example, the sealant may further contain component (D): a polymerization inhibitor.

[0086] (Component (D))

[0087] Component (D) is a polymerization inhibitor. Specific examples of component (D) include 2,2,6,6-tetramethylpiperidine-1-oxyl (free radical), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (free radical), 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (free radical), 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl (free radical), 4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl (free radical), 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (free radical), and 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (free radical).

[0088] From the viewpoints of improving plasma resistance and suppressing damage to the element to which the sealant is applied, the content of component (D) in the sealant is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.005% by mass or more, based on the total composition of the sealant.

[0089] In addition, from the viewpoint of improving the curability of the sealing material, the content of component (D) in the sealant is preferably 1% by mass or less, more preferably 0.75% by mass or less, and still more preferably 0.5% by mass or less, based on the total composition of the sealant.

[0090] (Other components)

[0091] Specific examples of components other than components (A) to (C) include, in addition to the above-mentioned component (D), one or more additives selected from the group consisting of tackifiers, fillers, curing accelerators, plasticizers, surfactants, heat stabilizers, flame retardants, antistatic agents, defoamers, leveling agents, and ultraviolet absorbers.

[0092] Next, the characteristics of the sealant will be described.

[0093] From the viewpoint of improving the heat resistance of the sealing material, the glass transition temperature (Tg) of the cured product of the sealant is 90°C or higher, preferably 110°C or higher, and more preferably 130°C or higher.

[0094] In addition, from the viewpoint of improving flexibility, the Tg of the cured product of the sealant is less than 200°C, preferably 190°C or lower, and more preferably 180°C or lower.

[0095] Here, the glass transition temperature (Tg) is measured in the following order.

[0096] The cured product of the sealant is obtained by sandwiching the uncured sealant between polyethylene terephthalate (PET) films with a 100-μm-thick Teflon (registered trademark) sheet as a mold frame, and curing it under the conditions of an illuminance of 1000 mW / cm 2 and a cumulative light quantity of 1500 mJ / cm 2 using a UV-LED with a wavelength of 395 nm.

[0097] The obtained cured product is cut into a size of 10 mm in width × 40 mm in length with a cutter.

[0098] Then, using a dynamic viscoelasticity measuring device “DMS6100” (manufactured by Seiko Instruments Inc.), while applying a frequency of 1 Hz to the cut cured product in the atmosphere, the temperature is raised from room temperature to 250°C at a rate of 5°C / minute, and tanδ is measured simultaneously. The peak temperature of tanδ is set as the Tg of the cured product.

[0099] In this embodiment, a sealant with a Tg within a specific range can be obtained, for example, by appropriately selecting the components and compounding ratios contained in the resin composition and adjusting the manufacturing conditions.

[0100] The properties of the sealant are not limited. From the viewpoints of improving the flexibility and plasma resistance of the sealing material and being suitable for forming a cured material by a coating method such as the inkjet method, the sealant is preferably liquid.

[0101] In addition, in the embodiment, from the viewpoint of stably forming a sealing material such as a resin film, the sealant is preferably a sealant for coating, and more preferably a sealant for coating by the inkjet method.

[0102] From the viewpoint of improving the inkjet dischargeability, the viscosity of the sealant measured using an E-type viscometer at 25°C and 20 rpm is preferably 5 mPa·s or more, more preferably 8 mPa·s or more, and further preferably 10 mPa·s or more.

[0103] In addition, from the viewpoint of improving the inkjet dischargeability, the viscosity of the above-mentioned sealant is preferably 30 mPa·s or less, more preferably 28.5 mPa·s or less, and further preferably 27 mPa·s or less.

[0104] From the viewpoint of improving the sealing characteristics of the sealant, the dielectric constant of the cured product of the sealant is preferably 4.0 or less, more preferably 3.8 or less, and further preferably 3.6 or less.

[0105] In addition, the dielectric constant of the cured product of the sealant can be set to 1.0 or more, for example.

[0106] Here, the dielectric constant of the cured product of the sealant is the dielectric constant measured at a frequency of 100 kHz for a cured product obtained by curing the curable composition under the conditions of using a UV-LED with a wavelength of 395 nm at an illuminance of 1000 mW / cm 2 and a cumulative light quantity of 1500 mJ / cm 2 .

[0107] Next, a method for manufacturing the sealant will be described.

[0108] The method for manufacturing the sealant is not limited. For example, it includes an operation of mixing components (A) to (C) and appropriate other components, such as various additives added as needed. As a method for mixing the respective components, for example, various known kneading machines such as a planetary stirring device, a homogenizing disperser, a universal mixer, a Banbury mixer, a kneader, a two-roll mill, a three-roll mill, and an extruder can be used alone or in combination, and uniformly kneaded under conditions such as at normal temperature or under heating, at normal pressure, reduced pressure, increased pressure, or in an inert gas stream.

[0109] In addition, the obtained sealant can also be used to form a sealing material. For example, the sealant can be coated on a substrate and dried. Coating can be performed using known methods such as an inkjet method, screen printing, and dispenser coating. In addition, drying can be performed, for example, by heating to a temperature at which component (A) does not polymerize. The shape of the obtained sealing material is not limited, and it can be formed into, for example, a film shape or a layer shape.

[0110] The sealing material is, for example, a cured product obtained by curing the sealant in the present embodiment, and more specifically, a photocured product of the sealant.

[0111] As a method for photocuring the sealant, for example, a method of curing by light irradiation using a light source such as a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an excimer laser, a chemical lamp, a black light, a microwave-excited mercury lamp, a metal halide lamp, a sodium lamp, a halogen lamp, a xenon lamp, an LED lamp, a fluorescent lamp, sunlight, and an electron beam irradiation device can be cited.

[0112] In the present embodiment, since the sealant composition contains components (A) to (C) and the Tg is within a specific range, by using such a sealant, a resin layer excellent in plasma resistance and high in flexibility can be formed. By using such a resin layer as a sealing material, a display device with excellent reliability can be obtained.

[0113] In addition, the sealant obtained in the present embodiment is suitable for use in, for example, sealing display elements, preferably organic EL display elements. According to the present embodiment, a sealant capable of forming a resin layer having excellent plasma resistance and high flexibility can be obtained. Therefore, for example, damage to display elements during the manufacturing process of display devices can be effectively suppressed, and the manufacturing stability of display devices can also be improved.

[0114] Hereinafter, a configuration example of a display device will be given taking an organic EL display device as an example.

[0115] (Organic EL display device)

[0116] In the present embodiment, the organic EL display device has a layer formed of a cured product of a sealant. By protecting the organic EL element with a resin layer obtained by curing the sealant of the present embodiment, it is possible to sufficiently prevent moisture from entering the organic EL element and maintain the performance and durability of the organic EL element at a high level.

[0117] The organic EL display device may have a top-emission structure or a bottom-emission structure.

[0118] Preferably, before the organic EL element is disposed on the substrate and protected by the resin layer obtained by curing the sealant in the present embodiment, the organic EL element is previously coated with an inorganic material film so as to cover the region including the organic EL element.

[0119] Figure 1 It is a cross-sectional view showing a configuration example of the organic EL display device in the present embodiment. Figure 1 The shown display device 100 is an organic EL display device, which includes a substrate (base material layer 50), an organic EL element (light-emitting element 10) disposed on the base material layer 50, and a sealing layer 22 (which may be an outer coating layer 22 or a barrier layer 22) covering the light-emitting element 10. And, for example, the sealing layer 22 is formed of a cured product of the sealant in the present embodiment.

[0120] In addition, Figure 1 In the display device 100, as a layer located more on the observation side than the light-emitting element 10, there are a barrier layer 21 (which may be a touch panel layer 21 or a surface protection layer 21), a sealing layer 22 (which may be an outer coating layer 22 or a barrier layer 22), a planarization layer 23 (which may be a sealing layer 23), and a barrier layer 24. The planarization layer 23 is provided on the base material layer 50 so as to cover the light-emitting element 10, and the barrier layer 24 is provided on the surface of the planarization layer 23. The sealing layer 22 is provided on the base material layer 50 so as to cover the planarization layer 23 and the barrier layer 24. In addition, a barrier layer 21 is provided on the sealing layer 22.

[0121] The material of the base material layer 50 is not limited. For example, various substrates such as a glass substrate, a silicon substrate, and a plastic substrate can be used. A TFT substrate having a plurality of TFTs (thin film transistors) and a planarization layer on the substrate can also be used.

[0122] As the inorganic material constituting the barrier layer 24, that is, the aforementioned inorganic material film, for example, silicon nitride (SiN x ), silicon oxide (SiO x ), aluminum oxide (Al2O3), etc. can be cited. The inorganic material film can be a single layer or a laminate of multiple layers.

[0123] Regarding the method of coating the light-emitting element 10 with the inorganic material film, for example, when the aforementioned inorganic material film is composed of silicon nitride and silicon oxide, a sputtering method, an electron cyclotron resonance (ECR) plasma CVD method, etc. can be cited.

[0124] Among them, in the sputtering method, for example, an argon gas, a nitrogen gas, or the like, alone or as a mixed gas, can be used as the carrier gas, and it can be carried out under the conditions of room temperature, a power of 50 to 1000 W, and a pressure of 0.001 to 0.1 Torr.

[0125] In addition, in the ECR plasma CVD method, for example, a mixed gas of SiH4 and O2 or a mixed gas of SiH4 and N2 can be used, and it can be carried out under the conditions of a temperature of 30°C to 100°C, a pressure of 10 mTorr to 1 Torr, a frequency of 2.45 GHz, and a power of 10 to 1000 W.

[0126] As a method of protecting the light-emitting element 10 by using a resin layer obtained by curing the sealant of the present embodiment, for example, the seal layer 22, for example, a method of coating the sealant on the light-emitting element 10 and curing it can be cited. As the coating method, an inkjet method is preferably used.

[0127] The thickness of the resin layer is not limited. From the viewpoints of improving the sealing performance and the flexural performance, for example, it is 0.1 to 50 μm, preferably 1 to 20 μm.

[0128] In addition, in the display device 100, in order to improve the effect of protecting the light-emitting element 10 from moisture and oxygen in the atmosphere, it is preferable to further laminate an inorganic material film (barrier layer 24) on the aforementioned resin layer. As the inorganic material and the formation method of the inorganic material film laminated on the resin layer, they are the same as those of the inorganic material film coating the light-emitting element 10.

[0129] The thickness of the inorganic material film formed on the aforementioned resin layer is not limited. From the viewpoint of improving the sealing performance, for example, it is 0.01 to 10 μm, preferably 0.1 to 5 μm.

[0130] In the display device 100, a barrier layer 24 and a sealing layer 22 are provided on the light-emitting element 10. The sealing layer 22 is composed of a resin layer obtained by curing the sealant in the present embodiment. Therefore, a display device 100 with excellent reliability can be obtained. Specifically, when the plasma treatment process is performed when forming the barrier layer 24 on the upper part of the sealing layer 22, damage to the barrier layer 24 can also be suppressed. In addition, for example, pinholes can be suppressed from being generated on the barrier layer 24 which is a SiN x film. Therefore, outgassing is not likely to occur when stored in a temperature range of about 85°C, for example, and thus damage to the light-emitting element 10 can be suppressed. In addition, the resin layer constituting the sealing layer 22 itself is not easily deteriorated by the plasma treatment, and thus damage to the light-emitting element 10 can be suppressed.

[0131] Examples

[0132] Hereinafter, the present invention will be described using examples and comparative examples, but the present invention is not limited thereto.

[0133] First, the materials used in the following examples are shown.

[0134] (A) UV curable resin 1: Dicyclopentanyl dimethacrylate, Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.

[0135] (A) UV curable resin 2: Trimethylolpropane triacrylate, Light Acrylate TMP-A, manufactured by Kyoeisha Chemical Co., Ltd.

[0136] (A) UV curable resin 3: Neopentyl glycol diacrylate, Light Acrylate NP-A, manufactured by Kyoeisha Chemical Co., Ltd.

[0137] (A) UV curable resin 4: 1,9-Nonanediol diacrylate, Light Acrylate 1,9ND-A, manufactured by Kyoeisha Chemical Co., Ltd.

[0138] (A) UV curable resin 5: Lauryl acrylate, Light Acrylate L-A, manufactured by Kyoeisha Chemical Co., Ltd.

[0139] (B) UV radical initiator 1: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, Omnirad TPO H, manufactured by IGM Resins B.V.

[0140] (C) Antioxidant 1: Butylated hydroxytoluene, BHT, manufactured by Tokyo Chemical Industry Co., Ltd.

[0141] (C) Antioxidant 2: Pentaerythritol Tetrakis [3-(3,5-Di-tert-butyl-4-hydroxyphenyl) Propionate], AO-60, manufactured by ADEKA Corporation

[0142] (D) Polymerization inhibitor: 4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-Oxyl Free Radical, manufactured by Tokyo Chemical Industry Co., Ltd.

[0143] (Examples 1 to 10, Comparative Examples 1 to 11)

[0144] The respective components were blended so as to have the blending compositions shown in Table 1 or Table 2, and a liquid curable composition was obtained as a sealant.

[0145] The physical properties of the sealant or its cured product obtained in each example were measured by the following method. The measurement results are summarized and shown in Tables 1 and 2.

[0146] (Glass transition temperature)

[0147] The cured product of the sealant obtained in each example was obtained in the following order. That is, a 100-μm-thick Teflon (registered trademark) sheet was used as a mold frame, the uncured sealant was sandwiched between PET films, and it was cured under the conditions of an illuminance of 1000 mW / cm 2 and an accumulated light quantity of 1500 mJ / cm 2 using a UV-LED with a wavelength of 395 nm to obtain a cured product.

[0148] The obtained cured product was cut into a size of 10 mm in width × 40 mm in length with a cutter.

[0149] Then, using a dynamic viscoelasticity measuring device "DMS6100" (manufactured by Seiko Instruments Inc.), while applying a frequency of 1 Hz to the cut cured product in the atmosphere, the temperature was raised from room temperature to 250°C at 5°C / min, and tanδ was measured simultaneously. The peak temperature of tanδ was set as the Tg of the cured product.

[0150] A cured product with a Tg of 90°C or higher and less than 200°C was judged as qualified (○), and a cured product with a Tg of less than 90°C or 200°C or higher was judged as unqualified (×).

[0151] (Viscosity)

[0152] The viscosity of the curable composition obtained in each example was measured at 25°C and 20 rpm using an E-type viscometer (LV DV-II+Pro, manufactured by BROOKFIELD).

[0153] (Dielectric constant)

[0154] A coating film for obtaining a cured product for dielectric constant measurement is produced by the following method. That is, the obtained sealant is introduced into an inkjet cartridge DMC-11610 (manufactured by Fujifilm Dimatix). The inkjet cartridge is placed on an inkjet device DMP-2831 (manufactured by Fujifilm Dimatix). After adjusting the ejection state, it is coated on a substrate obtained by vapor-depositing aluminum with a thickness of 100 nm on an alkali-free glass to a size of 5 cm × 5 cm so that the cured thickness reaches 10 μm.

[0155] The obtained coating film is placed in a box under the conditions of 5 minutes and room temperature (25 °C), and nitrogen is circulated. Then, ultraviolet light with a wavelength of 395 nm is irradiated under the conditions of an illuminance of 1000 mW / cm 2 and an accumulated light quantity of 1500 mJ / cm 2 to form a cured film.

[0156] Then, aluminum is vapor-deposited with a thickness of 100 nm on the inkjet coating surface, and the dielectric constant is measured at 100 kHz by the automatic balance bridge method using an LCR meter HP4284A (manufactured by Agilent Technologies).

[0157] (Evaluation method)

[0158] The damage of the organic EL element in the plasma treatment process is evaluated by the following method.

[0159] The sealant obtained in each example is introduced into an inkjet cartridge DMC-11610 (manufactured by Fujifilm Dimatix). The inkjet cartridge is placed on an inkjet device DMP-2831 (manufactured by Fujifilm Dimatix). After adjusting the ejection state, it is coated on a glass substrate to a size of 15 mm × 15 mm so that the cured thickness reaches 10 μm.

[0160] The obtained coating film is placed in a box under the conditions of 5 minutes and room temperature (25 °C), and nitrogen is circulated. Then, it is irradiated with ultraviolet light with a wavelength of 395 nm at 1500 mW / cm 2 for 1 second to form a cured film.

[0161] For the sample with the cured film formed, plasma treatment is performed for 1 minute under the conditions of a 2500 W ICP power supply, a 300 W RF power supply, a DC bias voltage of 200 V, an argon (Ar) flow rate of 50 sccm, and a pressure of 10 mtorr.

[0162] Then, an inorganic sealing layer (SiN x film) with a film thickness of 100 nm is formed by RF sputtering using a SiN x target.

[0163] On the other hand, an OLED element is vapor-deposited on the counter substrate and bonded to the substrate with an inorganic sealing layer formed thereon, thereby obtaining a test specimen for evaluation.

[0164] The reliability test of the specimens obtained in each example was carried out under the condition of 85 °C. Specifically, the luminous area ratio (%) after storing the specimens obtained in each example at 85 °C for 100 hours was obtained by the following method. That is, the luminous area at the initial state and after storing for 100 hours was calculated using Motic ImagesPlus software (manufactured by Shimadzu Rika Corporation), and the luminous area ratio was obtained and evaluated according to the following criteria. The specimens of ◎ and ○ were regarded as qualified.

[0165] ◎: 85% or more

[0166] ○: 75% or more and less than 85%

[0167] △: More than 50 and less than 75%

[0168] ×: 50% or less

[0169] (Flexural resistance)

[0170] The curable composition obtained in each example was introduced into an inkjet cartridge DMC-11610 (manufactured by Fujifilm Dimatix). The inkjet cartridge was placed in an inkjet device DMP-2831 (manufactured by Fujifilm Dimatix), and after adjusting the discharge state, it was coated on a 6 cm × 6 cm PET film (25 μm, A31) to a size of 5 cm × 5 cm so that the cured thickness became 10 μm. The obtained coating film was placed in a box under the conditions of 5 minutes and room temperature (25 °C) and nitrogen was circulated, and then irradiated with ultraviolet light having a wavelength of 395 nm at 1500 mW / cm 2 for 1 second to form a cured film.

[0171] The obtained cured film was used as a measurement specimen to evaluate the flexural resistance. Using a bending tester (DMLHP, manufactured by Yuasa System Co., Ltd.), the bending radius was set to 1 mm, the measurement specimen was fixed with double-sided tape (Nice Tack NW-15, manufactured by Mitsubond Corporation), and a bending test was carried out 300,000 times at a bending speed of 30 times per minute. After 300,000 times of bending, the appearance was visually confirmed within 10 minutes to evaluate the presence or absence of clouding.

[0172] The following shows the evaluation criteria. The specimens of ◎ and 〇 were regarded as qualified.

[0173] ◎: No clouding

[0174] 〇: No breakage, but there is clouding

[0175] ×: With fracture

[0176] [Table 1]

[0177]

[0178] [Table 2]

[0179]

[0180] According to Table 1 and Table 2, the sealants obtained in each example are excellent in suppressing damage to the organic EL element caused by plasma irradiation and have excellent bend resistance.

[0181] This application claims priority based on Japanese Patent Application No. 2020-157659 filed on September 18, 2020, and incorporates herein by reference all of the content disclosed therein.

[0182] Symbol Explanation

[0183] 10 Light-emitting element

[0184] 21 Barrier layer, touch panel layer or surface protection layer

[0185] 22 Seal layer, overcoat layer or barrier layer

[0186] 23 Planarization layer or seal layer

[0187] 24 Barrier layer

[0188] 50 Substrate layer

[0189] 100 Display device.

Claims

1. A sealant for display elements, comprising the following components (A) to (C): (A) A polymerizable compound, (B) A polymerization initiator, (C) An antioxidant, The glass transition temperature of the cured product of the sealant for display elements is 90°C or higher and less than 200°C, The component (A) includes a dicycloalkylene (meth)acrylate compound having an alicyclic structure and a dicycloalkylene (meth)acrylate compound having a chain structure, and the content of the dicycloalkylene (meth)acrylate compound having an alicyclic structure in the sealant for display elements is 25 parts by mass or more relative to 100 parts by mass of the polymerizable compound.

2. The sealant for display elements according to claim 1, wherein the component (C) is a hindered phenol compound.

3. The sealant for display elements according to claim 1 or 2, wherein the component (C) is at least one of dibutylhydroxytoluene and pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

4. The sealant for display elements according to claim 1 or 2, which is used for sealing an organic EL display element.

5. A cured product obtained by curing the sealant for display elements according to any one of claims 1 to 4.

6. A display device, comprising: a substrate, a display element disposed on the substrate, and a sealing layer covering the display element, The sealing layer is formed of a cured product of the sealant for display elements according to any one of claims 1 to 4.

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