Sealing material for OLED display elements, OLED display device, and manufacturing method of OLED display device

Abstract

The sealing material for organic EL display elements of the present invention comprises: a cationic polymerizable compound, a cationic polymerization initiator, an ultraviolet absorber, and a compound with phenolic hydroxyl groups. The mass ratio of the compound with phenolic hydroxyl groups to the ultraviolet absorber (compound with phenolic hydroxyl groups / ultraviolet absorber) is 0.01 or more and less than 1.00.

Description

[Technical Field]

[0001] This invention relates to a sealing material for organic EL display elements, an organic EL display device, and a method for manufacturing an organic EL display device. [Previous Technology]

[0002] In recent years, image display devices equipped with optical elements have been known, such as organic EL displays. In order to prevent the optical elements from deteriorating due to moisture in the atmosphere, such image display devices use a sealing layer to seal the optical elements.

[0003] A sealing layer system is formed, for example, by embedding an optical element in a sealing component and then using light irradiation to harden the sealing component.

[0004] Such sealing compositions are proposed, for example, as sealants for organic EL display elements containing cationic polymerizable compounds, polymerization initiators, and benzotriazole compounds (see, for example, Example 1 of Patent Document 1). [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2021 / 006070 [Summary of the Invention]

[0006] (The problem that the invention aims to solve)

[0007] On the other hand, if it is the sealant for organic EL display elements of Patent Document 1, even under weak light such as fluorescent lamps, acid will still be generated from the polymerization initiator (photoacid generator). This acid will remain unchanged and will not be activated, thus causing the sealant for organic EL display elements to polymerize (harden) and become sticky. In other words, the sealant for organic EL display elements of Patent Document 1 has the disadvantage of low stability under white light.

[0008] Furthermore, the hardened material of such sealing components is required to have reliability.

[0009] This invention provides: a sealing material for organic EL display elements that exhibits excellent stability to white light and high reliability after curing; an organic EL display device having a sealing layer composed of a cured form of the organic EL display element sealing material; and a method for manufacturing the organic EL display device. (Technical means to solve the problem)

[0010] The present invention [1] is a sealing material for an organic EL display element, comprising: a cationic polymerizable compound, a cationic polymerization initiator, an ultraviolet absorber, and a compound with phenolic hydroxyl groups; wherein the mass ratio of the above-mentioned compound with phenolic hydroxyl groups to the above-mentioned ultraviolet absorber (compound with phenolic hydroxyl groups / ultraviolet absorber) is 0.01 or more and less than 1.00.

[0011] The present invention [2] is a sealing material for an organic EL display element as described in [1] above, wherein the above-mentioned cationic polymeric compound is an epoxy compound and / or an oxobutane compound.

[0012] The present invention [3] is a sealing material for an organic EL display element as described in [1] or [2] above, wherein the ultraviolet absorber is a benzotriazole compound or a diphenyl ketone compound.

[0013] The present invention [4] is a sealing material for an organic EL display element as described in any one of [1] to [3] above, wherein the content of the ultraviolet absorber is 0.1% by mass or more and 2% by mass or less.

[0014] The present invention [5] is a sealing material for an organic EL display element as described in any one of [1] to [4] above, wherein the content of the compound having phenolic hydroxyl groups is 0.01% by mass or more and 0.5% by mass or less.

[0015] The present invention [6] is a sealing material for an organic EL display element as described in any one of [1] to [5] above, wherein it is liquid at 25°C and the solvent content is less than 0.05% by mass.

[0016] The present invention [7] is a sealing material for an organic EL display element as described in any of the above [1] to [6], wherein the viscosity at 25°C is 5 mPa·s or more and 50 mPa·s or less.

[0017] The present invention [8] is an organic EL display device comprising: a substrate, an organic EL element mounted on one side of the substrate in the thickness direction, and a sealing layer covering the organic EL element; wherein the sealing layer is composed of a hardened material of the sealing material for organic EL display elements described in any one of [1] to [7].

[0018] The present invention [9] is a method for manufacturing an organic EL display device, comprising: a first step of preparing a substrate; a second step of mounting an organic EL element on one side of the substrate in the thickness direction; and a third step of forming a sealing layer covering the organic EL element using an inkjet printing method; wherein the sealing layer is composed of a hardened material of the sealing material for organic EL display elements described in any one of [1] to [7] above. (Effects compared to prior art)

[0019] In the sealant for organic EL display elements of the present invention, the mass ratio of the compound with phenolic hydroxyl groups to the ultraviolet absorber (compound with phenolic hydroxyl groups / ultraviolet absorber) is 0.01 or more and less than 1.00. Because the mass ratio is 0.01 or more, the stability to white light is improved in this sealant for organic EL display elements. Furthermore, because the mass ratio is less than 1.00, the reliability after curing is improved in this sealant for organic EL display elements.

[0020] The organic EL display device of the present invention utilizes a sealing layer composed of a hardened material of the sealing material for organic EL display elements of the present invention to cover the organic EL element. Therefore, it has excellent reliability.

[0021] The method for manufacturing the organic EL display device of the present invention utilizes an inkjet printing method to form a sealing layer, which covers the organic EL element and is composed of a hardened material of the sealing material for the organic EL display element of the present invention. Therefore, it can manufacture an organic EL display device with excellent reliability.

Implementation Method

[0023] The sealing material for organic EL display elements contains: cationic polymerizable compounds, cationic polymerization initiators, ultraviolet absorbers, and compounds with phenolic hydroxyl groups.

[0024] <Catonic Polymerizable Compounds> Cationic polymerizable compounds include, for example, epoxy compounds and oxetane compounds. That is, the cationic polymerizable compounds are preferably epoxy compounds and / or oxetane compounds. Furthermore, the cationic polymerizable compounds are more preferably epoxy compounds and oxetane compounds.

[0025] [Epoxy Compound] Examples of epoxy compounds include alicyclic epoxy resins, aliphatic epoxy resins, and aromatic epoxy resins, with alicyclic epoxy resins and aliphatic epoxy resins being more preferred. More preferably, the epoxy compound is an alicyclic epoxy resin or an aliphatic epoxy resin, and even more preferably, it is an alicyclic epoxy resin or an aliphatic epoxy resin.

[0026] (Alicyclic epoxy resin) Alicyclic epoxy resin is a curable resin (light-curable resin, preferably ultraviolet-curable resin) that has epoxy groups and aliphatic rings (alicyclic skeleton) and no aromatic rings.

[0027] Examples of alicyclic epoxy resins include: alicyclic epoxy resins containing epoxypropyl groups, alicyclic epoxy resins containing epoxypropyl ether groups, and epoxy resins with an epoxy ring structure.

[0028] ((Alicyclic epoxy resin containing epoxypropyl)) The alicyclic epoxy resin containing epoxypropyl has epoxypropyl groups bonded to an aliphatic ring. Such alicyclic epoxy resin containing epoxypropyl is, for example, shown in the following general formula (1).

[0029] [Chemical 1] In formula (1), R1 represents a monovalent organic group; n represents the degree of polymerization. Also, alkyl and other substituents can be bonded to the carbon atoms constituting the cyclohexane ring.

[0030] The alicyclic epoxy resin containing glycidyl as shown in the above general formula (1) can be specifically exemplified by, for example, the 1,2-epoxy-4-(2-epoxyethylene)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol.

[0031] The alicyclic epoxy resin containing epoxy propylene as shown in the above general formula (1) can also be a commercially available product. Examples of commercially available alicyclic epoxy resin containing epoxy propylene as shown in the above general formula (1) include: EHPE3150 (epoxy equivalent 170~190g / eq., manufactured by Daicel).

[0032] ((Alicyclic epoxy resin containing glycidyl ether group)) The alicyclic epoxy resin containing glycidyl ether group has glycidyl ether units bonded to an aliphatic ring. Preferably, the alicyclic epoxy resin containing glycidyl ether group is a polyglycidyl ether-containing alicyclic epoxy resin having a plurality of glycidyl ether units bonded to an aliphatic ring.

[0033] Examples of alicyclic epoxy resins containing glycidyl ether include: difunctional alicyclic epoxy resins containing glycidyl ether. Examples of difunctional alicyclic epoxy resins containing glycidyl ether include: hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, and diglycidyl hexahydrophthalic acid.

[0034] ((Epoxy resin with epoxy ring structure)) The epoxy resin with epoxy ring structure has an epoxy ring structure consisting of two adjacent carbon atoms forming an aliphatic ring and one oxygen atom bonded to the two carbon atoms.

[0035] Examples of epoxy resins with an epoxy ring structure include epoxy resins containing an epoxy cyclohexane structure (hereinafter referred to as "epoxy resins containing an ECH structure").

[0036] Examples of epoxy resins containing ECH structures include: epoxy resins containing one ECH structure as shown in the following chemical formula (2), epoxy resins containing two ECH structures as shown in the following general formula (3), and modified versions thereof.

[0037] [Chemical 2]

[0038] [Chemical 3]

[0039] In formula (3), the X series represents the linking group (a divalent group having one or more atoms). The m series represents 0 or 1. The R 2 series represents one atom or substituent selected from the group consisting of hydrogen atom, fluorine atom, alkyl, fluoroalkyl, aryl, furanyl and thiophene. The two R 2 series in formula (3) may be the same or different.

[0040] The epoxy resin containing two ECH structures as shown in the general formula (3) above (hereinafter also referred to as "the epoxy resin containing ECH structure as shown in the general formula (3)") has an ECH structure (epoxycyclohexyl) at the two ends of the molecule, and the two epoxycyclohexyl groups are bonded by a linker (a carbon-carbon bond when m is 0). In addition, the epoxycyclohexyl group is a functional group containing: a cyclohexane ring, two adjacent carbon atoms forming the cyclohexane ring, and an epoxy group formed by an oxygen atom bonded to the two carbon atoms.

[0041] In the above general formula (3), the alkyl system represented by R2 can be, for example, straight-chain or branched alkyl groups having 1 to 6 carbon atoms (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.).

[0042] In the above general formula (3), the fluoroalkyl system represented by R2 can be, for example, straight-chain or branched-chain fluoroalkyl groups with 1 to 6 carbon atoms (e.g., perfluoromethyl, perfluoroethyl, perfluoropropyl, etc.).

[0043] In the above general formula (3), the aryl system represented by R2 can be, for example, aryl groups with 6 to 18 carbon atoms (e.g., phenyl, naphthyl, etc.).

[0044] In the above general formula (3), the connecting group system represented by X can be, for example, oxygen atom, sulfur atom, divalent hydrocarbon group, polyoxyalkylene group, carbonyl group, ether group, thioether group, ester group, carbonate group, amide group, and the group to which they are connected. In addition, when m is 0, the two ECH structures are bonded by carbon-carbon bonds.

[0045] Examples of divalent hydrocarbon groups include: straight-chain or branched chain alkyl groups with 1 to 20 carbon atoms (e.g., methylene, methylmethylene, dimethylmethylene, ethyl, propenyl, trimethylene, butyl, etc.), and straight-chain or branched chain unsaturated hydrocarbon groups with 1 to 20 carbon atoms (e.g., propenyl, methyl propenyl, butenyl, etc.).

[0046] Examples of polyoxyalkylene compounds include: straight-chain or branched polyoxyalkylene compounds with 1 to 120 carbon atoms (e.g., polyoxyethylene, polyoxypropylene, etc.).

[0047] The epoxy resin containing the ECH structure shown in general formula (3) may include, for example: (3,3',4,4'-diepoxy)dicyclohexyl, bis(3,4-epoxycyclohexylmethyl) ether, 1,2-bis(3,4-epoxycyclohexane-1-yl)ethane, 2,2-bis(3,4-epoxycyclohexane-1-yl)propane, (3,4-epoxy)cyclohexanecarboxylic acid-3,4-epoxycyclohexylmethyl ester, and ε-caprolactone-modified 3,4-epoxycyclohexanecarboxylic acid-3',4'-epoxycyclohexylmethyl ester, with (3,3',4,4'-diepoxy)dicyclohexyl (in the above formula (3), m represents 0 and R2 represents hydrogen atoms).

[0048] Furthermore, the epoxy resin with the ECH structure shown in the above general formula (3) can also be a commercially available product. Examples of commercially available epoxy resins containing the ECH structure shown in the above general formula (3) include: Celloxide 8000, Celloxide 8010, Celloxide 2021P, and Celloxide 2081 (all of which are manufactured by Daicel).

[0049] The epoxy resin containing the ECH structure is preferably the epoxy resin containing the ECH structure shown in the above general formula (3).

[0050] Furthermore, alicyclic epoxy resins are preferred, for example, epoxy resins with an epoxy ring structure.

[0051] The weight average molecular weight of the alicyclic epoxy resin is, for example, 200 or more, or, for example, 1000 or less, preferably 500 or less. The weight average molecular weight (Mw) is obtained using a gel permeation chromatography (GPC) analyzer with polystyrene as a standard (the same applies below).

[0052] Furthermore, the epoxy equivalent of the alicyclic epoxy resin is, for example, 90 g / eq. or more, preferably 100 g / eq. or more, and, for example, 250 g / eq. or less, preferably 190 g / eq. or less. The epoxy equivalent can be determined according to JIS K7236:2001 (the same applies below).

[0053] (Aliphatic epoxy resin) Examples of aliphatic epoxy resins include: difunctional aliphatic epoxy resins. Examples of difunctional aliphatic epoxy resins include: ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether, with neopentyl glycol diglycidyl ether being a preferred example.

[0054] The weight average molecular weight of aliphatic epoxy resin is, for example, 150 or more, or, for example, 400 or less.

[0055] Furthermore, the epoxy equivalent of aliphatic epoxy resin is, for example, 60 g / eq. or more, or, for example, 250 g / eq. or less.

[0056] When the epoxy compound contains both alicyclic and aliphatic epoxy resins, the content of the alicyclic epoxy resin relative to 100 parts by mass of the total amount of alicyclic and aliphatic epoxy resins is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, or, for example, 50 parts by mass or less, preferably 40 parts by mass or less. Furthermore, the content of the alicyclic epoxy resin relative to the cationic polymerizable compound is, for example, 5% by mass or more, preferably 10% by mass or more, or, for example, 30% by mass or less, preferably 20% by mass or less.

[0057] Furthermore, when the epoxy compound contains both alicyclic and aliphatic epoxy resins, the content of the aliphatic epoxy resin relative to 100 parts by mass of the total amount of alicyclic and aliphatic epoxy resins is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and also, for example, 90 parts by mass or less, preferably 80 parts by mass or less. Also, the content of the aliphatic epoxy resin relative to the cationic polymerizable compound is, for example, 20% by mass or more, preferably 30% by mass or more, and also, for example, 50% by mass or less, preferably 40% by mass or less.

[0058] Epoxy compounds can be used alone or in combination of two or more.

[0059] Furthermore, the content of the epoxy compound relative to the cationic polymeric compound is, for example, 30% or more by mass, preferably 40% or more by mass, or, for example, 70% or less by mass, preferably 60% or less by mass.

[0060] [Oxycyclic butane compounds] Oxycyclic butane compounds, for example, contain one or more but less than five oxycyclic butane rings.

[0061] Examples of oxetane compounds include: monofunctional oxetane compounds having one oxetane ring, difunctional oxetane compounds having two oxetane rings, and trifunctional or higher oxetane compounds having three or more oxetane rings.

[0062] Examples of monofunctional oxetane compounds include: 3-ethyl-3-hydroxymethyloxetane, 3-(methyl)allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetane-butylmethoxy)methylbenzene, 2-ethylhexyl(3-ethyl-3-oxetane-butylmethyl) ether, ethyl diethylene glycol(3-ethyl-3-oxetane-butylmethyl) ether, and 3-cyclohexylmethyl-3-ethyloxetane.

[0063] Examples of difunctional oxetane compounds include: 1,4-bis{[(3-ethyl-3-oxetane)methoxy]methyl}benzene, 3,3'-(oxadimethylene)bis(3-ethyloxetane), 1,4-bis[(3-ethyl-3-oxetane)methoxy]benzene, 1,3-bis[(3-ethyl-3-oxetane)methoxy]benzene, 3,7-bis(3-oxetane)-5-oxa-nonane, 1,4 - bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]benzene, 1,2-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]ethane, 1,2-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3-oxetane-butylmethyl) ether, and dicyclopentene bis(3-ethyl-3-oxetane-butylmethyl) ether, preferably 3,3'-(oxobismethylene)bis(3-ethyloxetane).

[0064] Examples of trifunctional or higher oxetane compounds include: trimethylolpropane tri(3-ethyl-3-oxetanebutylmethyl) ether, pentaerythritol tri(3-ethyl-3-oxetanebutylmethyl) ether, pentaerythritol tetra(3-ethyl-3-oxetanebutylmethyl) ether, and dipentaerythritol penta(3-ethyl-3-oxetanebutylmethyl) ether.

[0065] Commercially available oxetane compounds may also be used. Examples of commercially available oxetane compounds include: Arone oxetane OXT-221 (3,3'-(oxadimethylene)bis(3-ethyloxetane)) and Arone oxetane OXT-121 (both manufactured by Toa Synthetic Chemical Co., Ltd.).

[0066] Preferred systems of oxetane compounds include, for example, difunctional oxetane compounds.

[0067] Oxycyclic butane compounds can be used alone or in combination of two or more.

[0068] The content of the oxobutane compound relative to the cationic polymerizable compound is, for example, 30% by mass or more, preferably 40% by mass or more, and also, for example, 70% by mass or less, preferably 60% by mass or less.

[0069] Furthermore, the content of the cationic polymeric compound relative to the sealing material for organic EL display elements is, for example, 80% by mass or more, preferably 90% by mass or more, or, for example, 98% by mass or less.

[0070] <Catonic polymerization initiator> Cationic polymerization initiator is, for example, a photoacid generator that generates acid by light irradiation.

[0071] There are no particular restrictions on the cationic polymerization initiator; any known cationic polymerization initiator may be used.

[0072] Catonic polymerization initiators can be used alone or in combination of two or more.

[0073] The content of the cationic polymerization initiator relative to 100 parts by mass of the cationic polymerizable compound is, for example, 0.5 parts by mass or more, preferably 0.8 parts by mass or more, more preferably 1.3 parts by mass or more, and for example, 5 parts by mass or less, preferably 2.5 parts by mass or less.

[0074] Furthermore, the content of the cationic polymerization initiator relative to the sealing material for organic EL display elements is, for example, 0.5% by mass or more, preferably 1% by mass or more, and also, for example, 10% by mass or less, preferably 5% by mass or less.

[0075] <UV Absorber> The UV absorber absorbs white light and inhibits the generation of acid components from the cationic polymerization initiator.

[0076] Examples of ultraviolet absorbers include: benzotriazole compounds, diphenyl ketone compounds, triphenyl ketone compounds, and cyanoacrylate compounds.

[0077] Examples of benzotriazole compounds include: 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2,2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl, 2-(2'-hydroxy-5'-methyl-phenyl)benzotriazole, 2-(2'-hydroxy-3',5'-ditert-butyl-phenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methyl-phenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-ditert-butyl-phenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol, 2-(2-hydroxy-5-methylphenyl)benzotriazole, and 2-(2'-hydroxy-4'-n-octyloxyphenyl)benzotriazole. Preferred systems include, for example, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol, 2-(2-hydroxy-5-methylphenyl)benzotriazole, and 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole. More preferred systems include, for example, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol, 2-(2-hydroxy-5-methylphenyl)benzotriazole, and particularly preferred systems include, for example, 2-(2-hydroxy-5-methylphenyl)benzotriazole.

[0078] Commercially available benzotriazole compounds may also be used. Examples of commercially available benzotriazole compounds include: TINUVIN 234 [2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol, manufactured by BASF Japan Co., Ltd.], KEMISORB71 [2-(2-hydroxy-5-methylphenyl)benzotriazole, manufactured by CHEMIPRO Chemical Co., Ltd.], and RUVA-93 [2-(2-hydroxy-5-(2-(methacryloxy)ethyl)phenyl)-2H-benzotriazole, manufactured by Otsuka Chemical Co., Ltd.].

[0079] Examples of diphenyl ketone compounds include: [2-hydroxy-4-(octoxy)phenyl](phenyl) ketone, 2-hydroxy-4-n-octoxydiphenyl ketone, 2,4-dihydroxydiphenyl ketone, 2-hydroxy-4-methoxydiphenyl ketone, 2,2'-dihydroxy-4-methoxydiphenyl ketone, 2,2'-dihydroxy-4,4'-dimethoxydiphenyl ketone, 2,2'-dihydroxy-4,4'-dimethoxydiphenyl ketone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfonyl Diphenyl ketone, 2-hydroxy-4-methoxy-2'-carboxydiphenyl ketone, 2-hydroxy-4-methoxy-5-sulfodiphenyl ketone trihydrate, 2-hydroxy-4-n-dodecyloxydiphenyl ketone, 2-hydroxy-4-benzyloxydiphenyl ketone, 2,2',4,4'-tetrahydroxydiphenyl ketone, 2-hydroxy-4-dodecyloxydiphenyl ketone, and 2-hydroxy-4-(2-hydroxy-3-methylpropenoxy)propoxydiphenyl ketone. Preferred examples include: [2-hydroxy-4-(octoxy)phenyl](phenyl) ketone, and 2-hydroxy-4-n-octoxydiphenyl ketone. Even more preferred examples include: 2-hydroxy-4-n-octoxydiphenyl ketone.

[0080] Commercially available diphenyl ketone compounds may also be used. Examples of commercially available diphenyl ketone compounds include: KEMISORB12 (2-hydroxy-4-n-octyloxydiphenyl ketone, manufactured by CHEMIPRO Chemical Co., Ltd.) and ADK STAB 1413 ([2-hydroxy-4-(octyloxy)phenyl](phenyl)methyl ketone, manufactured by ADEKA Co., Ltd.).

[0081] Examples of tris(t) compounds include 2-[4,6-bis(2,4-dimethylyl)-1,3,5-tris(t)-2-yl]-5-octoxyphenol and 2,4-diphenyl-6-(2-hydroxy-4-hexoxyphenyl)-1,3,5-tris(t)-yl, with 2,4-diphenyl-6-(2-hydroxy-4-hexoxyphenyl)-1,3,5-tris(t)-yl.

[0082] Tris(II) compounds may also be commercially available. Examples of commercially available tris(II) compounds include: KEMISORB102 (2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-tris(II), manufactured by CHEMIPRO Chemical Co., Ltd.).

[0083] Cyanoacrylate compounds include, for example, ethyl-2-cyano-3-(3',4'-methylenedioxyphenyl)-acrylate.

[0084] The ultraviolet absorber is preferably a benzotriazole compound, a diphenyl ketone compound, or a triphenyl ketone compound, more preferably a benzotriazole compound or a diphenyl ketone compound, and particularly preferably the ultraviolet absorber is selected from a benzotriazole compound or a diphenyl ketone compound.

[0085] If the ultraviolet absorber is a benzotriazole compound or a diphenyl ketone compound, the stability to white light can be better.

[0086] The ultraviolet absorber is preferably a benzotriazole compound from the viewpoint of further improving the stability to white light.

[0087] Ultraviolet absorbers can be used alone or in combination of two or more types.

[0088] The content of the ultraviolet absorber relative to 100 parts by mass of the cationic polymeric compound is, for example, 0.05 parts by mass or more, preferably 0.4 parts by mass or more, more preferably 0.8 parts by mass or more, or, for example, 2 parts by mass or less, preferably 1.5 parts by mass or less.

[0089] Furthermore, the content of the ultraviolet absorber relative to the sealant for organic EL display elements is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.8% by mass or more, and for example, 2% by mass or less. From the viewpoint of improving the reliability of the sealant for organic EL display elements after curing, it is more preferably 1.5% by mass or less, and especially preferably 1.2% by mass or less.

[0090] If the content of the ultraviolet absorber is above the lower limit mentioned above, the stability to white light can be improved.

[0091] Furthermore, if the content of the ultraviolet absorber is below the above-mentioned upper limit, the hardening property can be maintained when hardening is carried out by irradiation with ultraviolet light.

[0092] <Compounds with phenolic hydroxyl groups> Compounds with phenolic hydroxyl groups are components that can capture acids generated from cationic polymerization initiators by irradiation with light.

[0093] A compound with a phenolic hydroxyl group is a compound having one or more phenolic hydroxyl groups in its molecule. Furthermore, a compound with a phenolic hydroxyl group does not include the aforementioned benzotriazole compound, the aforementioned diphenyl ketone compound, the aforementioned triphenyl ketone compound, and the aforementioned cyanoacrylate compound.

[0094] Preferably, such compounds with phenolic hydroxyl groups are monofunctional compounds having one benzene ring and one phenolic hydroxyl group on the benzene ring, difunctional compounds having one benzene ring and two phenolic hydroxyl groups on the benzene ring, and trifunctional compounds having one or more phenolic hydroxyl groups on the benzene ring. That is, compounds with phenolic hydroxyl groups preferably have one benzene ring. This provides excellent stability.

[0095] Compounds with a monofunctional phenolic hydroxyl group can be exemplified by the compound shown in formula (4) below. [Chemical 4] In the above formula (4), R3 represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and an alkyl ester group.

[0096] The following refers to alkyl groups having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl.

[0097] The alkyl ester group is shown in formula (5): -R 4-C(=O)-OR 5(5)

[0098] In the above formula (5), R4 series represents an alkyl group having 1 to 6 carbon atoms. Examples of alkyl groups having 1 to 6 carbon atoms include: methylene, methylmethylene, dimethylmethylene, ethyl alkyl, propyl alkyl, trimethylene, and butyl alkyl.

[0099] In the above formula (5), R5 series represents alkyl groups having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl.

[0100] This kind of monofunctional compound with phenolic hydroxyl group is preferably, for example: 2,6-ditert-butyl-p-cresol [a compound in formula (4) above where R3 is methyl], and phenylpropionic acid-3,5-bis(1,1-dimethylethyl)-4-hydroxy-C7-C9 side chain alkyl ester [a compound in formula (4) above where R3 is alkyl ester, and in formula (5) above where R4 is ethyl and R5 is heptyl, a compound in formula (5) above where R4 is ethyl and R5 is octyl, and a compound in formula (5) above where R4 is ethyl and R5 is nonyl], preferably 2,6-ditert-butyl-p-cresol.

[0101] That is, the compound shown in formula (4) above is preferably free of alkyl ester groups. Because the amount added contributes more to the white light stability, it is superior from the viewpoint of balancing white light stability and curing properties.

[0102] Examples of compounds with a bifunctional phenolic hydroxyl group include hydroquinone, resorcinol, tert-butylcatechol, and tert-butylhydroquinone.

[0103] Compounds with phenolic hydroxyl groups or more having trifunctional groups can be exemplified by gallol.

[0104] The compounds with phenolic hydroxyl groups are preferably monofunctional compounds with phenolic hydroxyl groups and difunctional compounds with phenolic hydroxyl groups. From the viewpoint of balancing white light stability and curing properties, monofunctional compounds with phenolic hydroxyl groups are more preferred.

[0105] Furthermore, the molecular weight of the compound with phenolic hydroxyl groups is, for example, 94 or more, preferably 100 or more, more preferably 200 or more, and, for example, 1000 or less, preferably 500 or less. From the viewpoint of balancing white light stability and curability, it is more preferably 300 or less. If the molecular weight is lower, the amount added contributes more to the white light stability, and therefore it is superior from the viewpoint of balancing white light stability and curability.

[0106] Compounds with phenolic hydroxyl groups can be used alone or in combination of two or more.

[0107] The content of the compound with phenolic hydroxyl groups relative to 100 parts by mass of the cationic polymeric compound is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.08 parts by mass or more, and especially preferably 0.1 parts by mass or more; and, for example, 0.5 parts by mass or less, preferably 0.3 parts by mass or less, and even more preferably 0.15 parts by mass or less.

[0108] Furthermore, the content of the compound with phenolic hydroxyl groups relative to the sealing material for organic EL display elements is, for example, 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.08% by mass or more, and especially preferably 0.1% by mass or more; and, for example, 0.5% by mass or less, preferably 0.3% by mass or less, and even more preferably 0.15% by mass or less.

[0109] If the content of a compound with phenolic hydroxyl groups reaches or exceeds the lower limit mentioned above, the stability to white light can be improved.

[0110] Furthermore, if the content of compounds with phenolic hydroxyl groups is below the above-mentioned upper limit, the hardening properties are excellent.

[0111] Furthermore, the mass ratio of the compound with phenolic hydroxyl groups to the ultraviolet absorber (compound with phenolic hydroxyl groups / ultraviolet absorber) is 0.01 or more, preferably 0.03 or more, even more preferably 0.07 or more, particularly preferably 0.09 or more, and even more preferably 0.1 or more; also, preferably less than 1.00, even more preferably 0.5 or less, particularly preferably 0.3 or less, and even more preferably 0.2 or less.

[0112] If the above mass ratio reaches or exceeds the lower limit, the stability to white light can be improved.

[0113] On the other hand, if the above mass ratio does not meet the lower limit, the stability to white light is reduced.

[0114] Furthermore, if the above mass ratio is below the above upper limit, the reliability of the sealing material for organic EL display elements is excellent.

[0115] On the other hand, if the above mass ratio exceeds the above upper limit, the reliability of the sealing material for organic EL display elements will decrease.

[0116] <Preparation of Sealant for Organic EL Display Elements> In preparing a sealant for an organic EL display element, a cationic polymerizable compound, an ultraviolet absorber, and a compound with phenolic hydroxyl groups are first mixed to prepare a mixture. Next, a cationic polymerization initiator is incorporated into the mixture and mixed. The sealant for an organic EL display element is thus prepared.

[0117] In the above modulation, additives may also be added as needed. That is, the sealing material for organic EL display elements may also contain additives.

[0118] Examples of additives include: sensitizers, thickeners, antioxidants, polymerization initiators, anti-aging agents, wetting modifiers, surfactants, plasticizers, ultraviolet absorbers, preservatives, and antibacterial agents.

[0119] The blending ratio of additives can be appropriately set according to the use and purpose.

[0120] Additives may be used alone or in combination of two or more.

[0121] Furthermore, the sealant for organic EL display elements may also contain solvents, but it is preferable that the sealant for organic EL display elements is substantially solvent-free. Specifically, the solvent content is, for example, less than 0.05% by mass, preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass.

[0122] <Physical Properties of Sealant for Organic EL Display Components> Sealant for organic EL display components is preferably in a liquid state at 25°C. "In a liquid state at 25°C" is defined as a viscosity at 25°C of 5 mPa·s or higher and 50 mPa·s or lower. If the sealant for organic EL display components is in a liquid state at 25°C, its inkjet ejection performance is excellent.

[0123] Furthermore, the viscosity at 25°C (initial viscosity described below) is, for example, 1 mPa·s or more, preferably 5 mPa·s or more, more preferably 10 mPa·s or more, or, for example, 50 mPa·s or less, preferably 30 mPa·s or less, more preferably 25 mPa·s or less.

[0124] The method for measuring the viscosity described above will be detailed in the following examples.

[0125] Furthermore, the cured material of the sealant for organic EL display elements preferably has transparency. Specifically, the total light transmittance (according to JIS K 7361-1) of the cured material of the sealant for organic EL display elements is, for example, 80% or more, preferably 85% or more, more preferably 90% or more, and, for example, 100% or less.

[0126] <Effects> In this sealant for organic EL display elements, the mass ratio of the compound with phenolic hydroxyl groups to the ultraviolet absorber (compound with phenolic hydroxyl groups / ultraviolet absorber) is 0.01 or more and less than 1.00. Because this mass ratio is 0.01 or more, the stability to white light is improved in this sealant for organic EL display elements. Furthermore, because this mass ratio is less than 1.00, from a curing point of view, the reliability of the cured organic EL element is improved in this sealant.

[0127] Furthermore, because this type of sealant for organic EL display elements exhibits superior stability to white light and high reliability after curing, it is well-suited for use as a sealant for organic EL display elements. In particular, because this sealant for organic EL display elements is stable to white light, it can suppress adhesion. Therefore, it is well-suited for inkjet printing.

[0128] <Variation Example> The above description describes that when preparing a sealing material for an organic EL display element, a cationic polymerizable compound, an ultraviolet absorber, and a compound with phenolic hydroxyl groups are first mixed to obtain a mixture, and then a cationic polymerization initiator is incorporated into the mixture. However, the cationic polymerizable compound, the ultraviolet absorber, and the compound with phenolic hydroxyl groups can also be incorporated together with the cationic polymerization initiator.

[0129] <Organic EL Display Device> Referring to FIG1, an embodiment of the organic EL display device of the present invention will be described.

[0130] The organic EL display device 10 includes: a substrate 1, an organic EL element 2 mounted on one side of the substrate 1 in the thickness direction, and a sealing layer 3 covering the organic EL element 2.

[0131] [Substrate] Substrate 1 supports organic EL element 2.

[0132] Substrate 1 can be, for example, a glass substrate and a plastic substrate, but preferably a glass substrate.

[0133] The thickness of substrate 1 is, for example, 0.1 mm or more, or, for example, 20 mm or less.

[0134] [Organic EL Element] The organic EL element 2 is a known organic EL element, mounted on the substrate 1. Although not shown, the organic EL element 2 includes: a cathode reflective electrode, an organic EL layer, and an anode transparent electrode.

[0135] The sealing layer 3 is a layer that is used to suppress the organic EL element 2 from being degraded by moisture in the atmosphere.

[0136] The sealing layer 3 is composed of a hardened material of the above-mentioned sealing material for organic EL display elements.

[0137] The thickness of the sealing layer 3 is, for example, 1 μm or more, or, for example, 100 μm or less.

[0138] <Manufacturing Method of Organic EL Display Device> Referring to FIGS. 2A to 2C, an embodiment of the manufacturing method of the organic EL display device of the present invention will be described.

[0139] The method for manufacturing an organic EL display device includes: a first step of preparing a substrate 1; a second step of mounting an organic EL element 2 on one side of the substrate 1 in the thickness direction; and a third step of forming a sealing layer 3 covering the organic EL element 2 using an inkjet method.

[0140] [Step 1] In step 1, as shown in Figure 2A, substrate 1 is prepared.

[0141] [Step 2] In step 2, as shown in FIG2B, an organic EL element 2 is mounted on one side of the substrate 1 in the thickness direction, for example using a known method (e.g., vacuum evaporation).

[0142] [Step 3] In step 3, as shown in Figure 2C, a sealing layer 3 is formed on the organic EL element 2 using an inkjet method. The organic EL element 2 can be reliably sealed using an inkjet method.

[0143] Specifically, firstly, an organic EL display element sealant is prepared to cover the organic EL element 2 using an inkjet printing method. Then, the organic EL display element sealant is irradiated to harden it. In this way, an organic EL display device 10 can be manufactured.

[0144] The organic EL display device 10 uses a sealing layer 3 made of a hardened material of a sealing material for organic EL display elements with excellent reliability to cover the organic EL element 2. Therefore, it has excellent reliability.

[0145] Furthermore, the method for manufacturing an organic EL display device involves forming a sealing layer 3, which is composed of a hardened material of an organic EL element 2 coated with an inkjet printer and a sealing material for an organic EL display element with excellent reliability. Therefore, it is possible to manufacture an organic EL display device 10 with excellent reliability.

[0146] Furthermore, although not shown in the figures, the organic EL display device 10 may also have another sealing layer (e.g., an inorganic sealing layer) provided on one side in the thickness direction and / or the other side in the thickness direction. [Example]

[0147] Next, the present invention will be described with reference to embodiments and comparative examples, but the present invention is not limited to the embodiments described below. In addition, "parts" and "%" refer to mass basis unless otherwise stated. Furthermore, the specific values ​​of blending ratios (including proportions), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (defined as "less than" or "less than") or lower limit (defined as "more than" or "exceeding") values ​​of the blending ratios (including proportions), physical property values, parameters, etc., corresponding to the above-described "embodiments".

[0148] <Detailed Information on Ingredients> The following details the trade names and abbreviations of the ingredients used in each embodiment and comparative example. CEL8010: (3,3',4,4'-diepoxy)biscyclohexyl, trade name "Celloxide 8010", Daicel NPG(G): neopentyl glycol diepoxypropyl ether, Sakamoto Pharmaceutical Co., Ltd. OXT221: 3,3'-(oxadimethylene)bis(3-ethyloxetane), trade name "Arone oxetane" OXT-221, Tinuvin 234 (Toa Synthetic Chemicals Co., Ltd.): 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol, KEMISORB71 (BASF Japan Co., Ltd.): 2-(2-hydroxy-5-methylphenyl)benzotriazole, RUVA-93 (CHEMIPRO Chemicals Co., Ltd.): 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, KEMISORB12 (Otsuka Chemicals Co., Ltd.): 2-hydroxy-4-n-octyloxydiphenyl ketone, ADK STAB (CHEMIPRO Chemicals Co., Ltd.) 1413: [2-Hydroxy-4-(Octoxy)phenyl](phenyl)methyl ketone, manufactured by ADEKA. KEMISORB102: 2,4-Diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-trimethylphenyl ether, manufactured by CHEMIPRO. BHT: 2,6-Di-tertiary-butyl-p-cresol, molecular weight 220. Irganox1135: 3,5-Bis(1,1-dimethylethyl)-4-hydroxy-C7-C9 alkyl ester, molecular weight 390.

[0149] <Preparation of Sealant for Organic EL Display Elements> [Examples 1-11 and Comparative Examples 1-6] According to the formulation described in Table 1, a cationic polymerizable compound, an ultraviolet absorber, and a compound with phenolic hydroxyl groups were first mixed to prepare a mixture. Next, a cationic polymerization initiator was incorporated into the mixture and mixed. In this way, a sealant for organic EL display elements was prepared.

[0150] <Evaluation> [Stability to White Light] The viscosity of the sealant for organic EL display elements in each example and comparative example was measured. Specifically, an E-type viscometer (LV-DV-II+ Pro, manufactured by BROOKFIELD, rotor angle: 1°, rotor radius: 24mm) was used according to the cone / plate viscometer method of JIS K5600-2-3 (2014), and the viscosity at 25°C (initial viscosity) was measured immediately after modulation (within 60 minutes after modulation). The cone / plate rotation speed during measurement was set to 20 rpm.

[0151] Then, 10 ml of the organic EL was measured using a sealing material with a display element and placed in a colorless, transparent 20 ml sample vial. The vial was then rotated for 6 hours on a mixing rotor set at a fluorescent lamp brightness of 600 lux. The viscosity (viscosity after 6 hours) was measured under the same conditions as described above using an E-type viscometer.

[0152] Then, the viscosity increase rate is calculated according to the following formula (6). The results are shown in Table 1. Viscosity increase rate = (viscosity after 6 hours / initial viscosity) - 1 (6)

[0153] Furthermore, the stability of white light was evaluated according to the following criteria. The results are shown in Table 1. ○: Thickness increase rate less than 20%. △: Thickness increase rate of 20% or more but less than 50%. ×: Thickness increase rate of 50% or more.

[0154] [Coating Stability] The sealant for organic EL display elements of each embodiment and comparative example was introduced into an ink cartridge DMC-11610 (manufactured by FUJIFILM Dimatix). The ink cartridge was installed in an inkjet printer DMP-2831 (manufactured by FUJIFILM Dimatix) placed under a fluorescent lamp. After adjusting the coating conditions, 1000 drops were coated onto a 50mm × 50mm alkali-free glass surface at 500μm intervals. Then, the sealant for organic EL display elements was placed under a fluorescent lamp for 3 hours. The ink cartridge was used again to coat 1000 drops onto the alkali-free glass surface at 500μm intervals, and the number of drops that could not be coated was determined. Coating stability was evaluated according to the following criteria. The results are shown in Table 1. ○: The number of droplets that could not be coated after 3 hours of placement was more than 98% lower than before placement. △: The number of droplets that cannot be coated after 3 hours is more than 90% but less than 98% of the number before. ×: The number of droplets that cannot be coated after 3 hours is less than 90% of the number before.

[0155] [Curing Rate] (Fabrication of Evaluation Substrate) The sealant for organic EL display elements of each embodiment and comparative example was introduced into an ink cartridge DMC-11610 (manufactured by FUJIFILM Dimatix). The ink cartridge was installed in an inkjet printer DMP-2831 (manufactured by FUJIFILM Dimatix), and after coating condition adjustment, a 40mm × 40mm layer was coated onto a 50mm × 50mm alkali-free glass substrate, resulting in a cured thickness of 10μm. This yielded a coating film. Next, the coating film was placed at 25°C and 50% humidity for 1 minute, and then irradiated with a 395nm wavelength UV-LED at 100mW / cm² and 1500mJ / cm² to cure it. This was used to manufacture an evaluation substrate.

[0156] (Determination of curing rate) FT-IR measurements were performed on the sealing material for organic EL display elements and the evaluation substrate of each embodiment and comparative example.

[0157] Then, using the wavenumber peak height (P1) at 1371 cm⁻¹ (belonging to the CH- stretching vibration peak) as a control, the ratio of the wavenumber peak height (P2) at 831 cm⁻¹ (belonging to the epoxy group peak) was calculated, and the hardening rate was calculated according to the following formula (7). The results are shown in Table 1. {(P2b / P1b)-(P2a / P1a)} / (P2b / P1b)×100 (7)

[0158] In the above formula (7), P1a represents the peak height of the wavenumber at 1371cm-1 after hardening, P1b represents the peak height of the wavenumber at 1371cm-1 before hardening, P2a represents the peak height of the wavenumber at 831cm-1 after hardening, and P2b represents the peak height of the wavenumber at 831cm-1 before hardening.

[0159] [Reliability of Organic EL Components] The sealing materials for organic EL display components of each embodiment and comparative example were introduced into an ink cartridge DMC-11610 (manufactured by FUJIFILM Dimatix). The ink cartridge was installed in an inkjet printer DMP-2831 (manufactured by FUJIFILM Dimatix), and after adjusting the ejection state, a 15mm × 15mm coating was applied to a glass substrate with a hardened thickness of 10μm to obtain a coating film.

[0160] Next, after placing the coating at 25°C and 50% humidity for 1 minute, the coating is irradiated with a 395nm UV-LED at a light intensity of 100mW / cm² and 1500mJ / cm² to harden it, thus obtaining a hardened film.

[0161] Next, the hardened film was subjected to plasma treatment for 1 minute under the following conditions: 2500W (ICP power supply), 300W (RF power supply), DC bias voltage 200V, argon (Ar) flow rate 50sccm, and pressure 10mtorr.

[0162] Then, using a SiNx target, an inorganic sealing layer (SiNx film) with a thickness of 100 nm is formed on the hardened film side by RF sputtering. The first evaluation substrate is thus obtained.

[0163] In addition, an organic EL element is mounted on another glass substrate to obtain a second evaluation substrate. Then, the first evaluation substrate and the second evaluation substrate are bonded together. An organic EL display device for evaluation is thus obtained.

[0164] Next, a reliability test was conducted on the organic EL display devices for evaluation at 85°C. Specifically, after each organic EL display device for evaluation was stored at 85°C for 100 hours, the luminous area ratio (%) was calculated according to the following method. That is, using the Motic Images Plus software (manufactured by Shimadzu Rika Co., Ltd.), the luminous area in the initial state and the luminous area after 100 hours of storage were calculated, and then the luminous area ratio was calculated according to the following formula (8). Luminous area ratio (%) = luminous area after 100 hours of storage / luminous area in the initial state × 100 (8)

[0165] The reliability of organic EL elements was evaluated according to the following criteria. The results are shown in Table 1. ○: Emissivity of luminescent area is 80% or more. △: Emissivity of luminescent area is 50% or more but less than 80%. ×: Emissivity of luminescent area is less than 50%.

[0166] [Table 1] Table 1 Example / Comparative Example No. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 cation Aggregation compound Epoxidation Compounds Alicyclic ring Oxygen resin CEL8010 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 Aliphatic ring Oxygen resin NPG(D) 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 oxacyclobutane compounds OXT-221 46.9 46.9 47.0 47.6 47.7 46.9 45.9 46.9 46.9 46.9 46.9 46.0 48.0 45.5 46.5 47.0 47.0 cationic polymerization initiator 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Ultraviolet rays absorbent benzotriazole compounds Tinuvin234 1.0 1.0 1.0 0.25 - - - - - - - 1.0 - 1.0 0.5 1.0 - KEMISORB71 - - - - 0.25 1.0 2.0 - - - - - - - - - 1.0 RUVA-93 - - - - - - - 1.0 - - - - - - - - - Diphenyl ketone compounds KEMISORB12 - - - - - - - - 1.0 - - - - - - - - ADK STAB 1413 - - - - - - - - - 1.0 - - - - - - - Tri-compound KEMISORB102 - - - - - - - - - - 1.0 - - - - - - Compounds containing phenolic hydroxyl groups BHT 0.100 - 0.020 0.200 0.100 0.100 0.100 0.100 0.100 0.100 0.100 1.000 - 1.500 1.000 - - Irganox1135 - 0.100 - - - - - - - - - - - - - - - total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 The mass ratio of compounds with phenolic hydroxyl groups to ultraviolet absorbers 0.100 0.100 0.020 0.800 0.400 0.100 0.050 0.100 0.100 0.100 0.100 1.000 - 1.500 2.000 - - evaluate For white The peace of light Qualitative Initial viscosity (mPa·s) 17.2 17.2 17.2 16.4 16.5 17.1 18.2 17.2 17.1 17.2 17.1 17.6 16.2 18.6 16.9 17.1 17.1 Viscosity (mPa·s) after 6 hours 19.3 20.5 25.0 20.6 22.6 18.8 18.6 20.0 19.8 20.1 22.7 18.8 gelation 18.8 17.3 29.4 35.2 viscosity increase 12% 19% 45% 26% 37% 10% 2% 16% 16% 17% 33% 7% - 1% 2% 72% 106% judge ○ ○ △ △ △ ○ ○ ○ ○ ○ △ ○ × ○ ○ × × Coating stability ○ ○ △ ○ △ ○ ○ ○ ○ ○ △ × × ○ ○ △ △ Hardening rate (%) 82 81 80 74 83 81 72 78 80 75 68 55 84 52 60 83 84 Reliability of organic EL components ○ ○ △ ○ ○ ○ △ ○ ○ ○ △ × ○ × × ○ 〇

[0167] Furthermore, the above-described embodiments are illustrative only and not restrictive. All variations of the invention that can be easily conceived by those skilled in the art are covered within the scope of the patent applications described below. (Industrial Applicability)

[0168] The sealing material for organic EL display elements, the organic EL display device, and the manufacturing method of the organic EL display device of the present invention can be applied to the manufacturing of image display devices. [Simplified Explanation of the Diagram]

[0022] FIG1 is a cross-sectional view of an embodiment of the organic EL display device of the present invention. FIG2, FIG2A to FIG2C are schematic diagrams of an embodiment of the manufacturing method of the organic EL display device of the present invention; wherein, FIG2A is the first step of preparing the substrate; FIG2B is the second step of mounting the organic EL element on one side of the substrate in the thickness direction; FIG2C is the third step of forming the sealing layer 3 covering the organic EL element 2 using inkjet printing.

Claims

1. A sealing material for organic EL display elements, comprising: a cationic polymerizable compound, a cationic polymerization initiator, an ultraviolet absorber, and a compound with phenolic hydroxyl groups; wherein, The mass ratio of the compound with phenolic hydroxyl groups to the ultraviolet absorber (compound with phenolic hydroxyl groups / ultraviolet absorber) is 0.05 or more but less than 1.00; the ultraviolet absorber contains a benzotriazole compound; the benzotriazole compound contains 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol or 2-(2-hydroxy-5-methylphenyl)benzotriazole; the compound with phenolic hydroxyl groups contains 2,6-di-tert-butyl-p-cresol.

2. As in claim 1, the sealing material for organic EL display elements, wherein, The aforementioned cationic polymerizable compounds are epoxy compounds and / or oxobutane compounds.

3. As in claim 1, the sealing material for organic EL display elements, wherein, The aforementioned ultraviolet absorber is a benzotriazole compound containing 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol or 2-(2-hydroxy-5-methylphenyl)benzotriazole.

4. As in claim 1, the sealing material for organic EL display elements, wherein, The content of the above-mentioned ultraviolet absorber is 0.1% by mass or more and 2% by mass or less.

5. As in claim 1, the sealing material for organic EL display elements, wherein, The content of the above-mentioned compounds with phenolic hydroxyl groups is 0.01% by mass or more and 0.5% by mass or less.

6. As in claim 1, the sealing material for organic EL display elements, wherein, It is liquid at 25℃, and the solvent content is less than 0.05% by mass.

7. As in claim 1, the sealing material for organic EL display elements, wherein, The viscosity at 25°C is above 5 mPa·s and below 50 mPa·s.

8. An organic EL display device comprising: a substrate; an organic EL element mounted on one side of the substrate in the thickness direction; and a sealing layer covering the organic EL element; wherein, The aforementioned sealing layer is composed of a hardened material of the sealing material for organic EL display elements as described in claim 1.

9. A method for manufacturing an organic EL display device, comprising: a first step of preparing a substrate; a second step of mounting an organic EL element on one side of the substrate in the thickness direction; and a third step of forming a sealing layer covering the organic EL element using an inkjet printing method; wherein, The aforementioned sealing layer is composed of a hardened material of the sealing material for organic EL display elements as described in claim 1.

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