JP7493058B2 - Encapsulating material for organic EL display element, cured product thereof, and organic EL display device - Google Patents

Description

The present invention relates to a sealing material for organic electroluminescence display elements, a cured product thereof, and an organic electroluminescence display device.

In the field of organic EL display elements, studies are being conducted to improve the properties of the sealing materials that seal organic EL display elements.

Organic EL display elements are becoming increasingly used in displays and lighting devices due to their low power consumption. Organic EL display elements are susceptible to deterioration due to moisture and oxygen in the air, so they are sealed with various sealing materials before use, and there is a need to improve the durability of various sealing materials against moisture and oxygen in order to put them into practical use.

As a method for sealing an organic EL display element, a method of alternately laminating an inorganic material and an organic material for sealing is used. For example, a method is used in which a first inorganic material film is coated on the element, a sealing layer is formed on the first inorganic material film, and a second inorganic material film is further coated on the sealing layer.
Since these inorganic material films have a high refractive index, the sealing layer in contact with the inorganic material film is required to have a high refractive index in order to suppress light reflection occurring at the interface with the inorganic material film.

Here, examples of a method for covering the sealing layer with an inorganic material film include a method for forming an inorganic material film made of silicon nitride or silicon oxide by vapor deposition, such as a sputtering method or an electron cyclotron resonance plasma CVD method.
Since the surface of the sealing layer is exposed to plasma during deposition, the sealing layer is required to have plasma resistance, that is, to be resistant to deterioration by plasma treatment or the like.

Patent Document 1 describes a composition for sealing an organic light-emitting device, which contains a sulfur-based photocurable monomer, a non-sulfur-based photocurable monomer, and a polymerization initiator.
Patent Document 2 describes a resin composition containing a cyclic (meth)acrylate compound and a polymerization initiator.
Patent Document 3 describes a curable composition containing a thioepoxy resin obtained by polymerizing a thioepoxy group-containing fluorene derivative and a dithiol compound.

JP 2019-537217 A JP 2014-229496 A JP 2019-172880 A

As described above, in order to suppress the reflection of light at the interface with the inorganic material film, the cured product of the sealing material for the organic EL display device is required to have a high refractive index. In this regard, the cured products of the resin compositions described in Patent Documents 1 and 2 all have a low refractive index of less than 1.60, leaving room for improvement.
Furthermore, the resin composition disclosed in Patent Document 2 may have low plasma resistance depending on the type of (meth)acrylate compound.
Furthermore, the resin composition described in Patent Document 3 has a high viscosity, and therefore there is room for improvement in terms of coatability by screen printing or inkjet printing.

The present invention has been made in consideration of the descriptions in these patent documents, and provides an encapsulating material for organic EL display elements that has an excellent balance of viscosity, plasma resistance, and refractive index when cured.

［上記一般式（１）中、Ｒ_１は水素原子またはメチル基を表し、＊は結合位置を表す。］
［２］ 上記化合物（Ａ）が上記（メタ）アクリルチオ基を２個以上有する化合物である、［１］に記載の有機ＥＬ表示素子用封止材。
［３］ （メタ）アクリル基を有する化合物（Ｂ）（但し上記化合物（Ａ）を除く。）をさらに含有する、上記［１］又は［２］に記載の有機ＥＬ表示素子用封止材。
［４］ 上記化合物（Ｂ）が、置換されてもよい芳香族基をさらに有する化合物である、上記［３］に記載の有機ＥＬ表示素子用封止材。
［５］ Ｅ型粘度計で測定される２５℃、２０ｒｐｍにおける粘度が、５ｍＰａ・ｓ以上５０ｍＰａ・ｓ以下である、上記［１］～［４］のいずれか１つに記載の有機ＥＬ表示素子用封止材。
［６］ インクジェット法による塗布に用いられる、上記［１］～［５］のいずれか１つに記載の有機ＥＬ表示素子用封止材。
［７］ 有機ＥＬ表示素子、第１の無機材料膜、封止層、第２の無機材料膜がこの順序で積層された構造を有する有機ＥＬ表示装置において、上記封止層の形成に用いられる、上記［１］～［６］のいずれか１つに記載の有機ＥＬ表示素子用封止材。
［８］ ダム材とフィル材を用いた封止構造において、上記フィル材として用いられる、上記［１］～［７］のいずれか１つに記載の有機ＥＬ表示素子用封止材。
［９］ 上記［１］～［８］のいずれか１つに記載の有機ＥＬ表示素子用封止材を硬化してなる硬化物。
［１０］ 有機ＥＬ表示素子と、
上記有機ＥＬ表示素子を被覆する封止層と、
を含み、上記封止層が、上記［９］に記載の硬化物を含有する、有機ＥＬ表示装置。 According to the present invention, there are provided a sealing material for an organic EL display element, a cured product thereof, and an organic EL display device, as shown below.
[1] A sealing material for an organic electroluminescence display element, comprising a compound (A) having a (meth)acrylthio group represented by the following general formula (1):

[In the above general formula (1), R ₁ represents a hydrogen atom or a methyl group, and * represents a bonding position.]
[2] The sealing material for an organic EL display element according to [1], wherein the compound (A) is a compound having two or more of the (meth)acrylthio groups.
[3] The sealing material for an organic EL display element according to the above [1] or [2], further comprising a compound (B) having a (meth)acrylic group (excluding the above compound (A)).
[4] The sealing material for an organic EL display element according to the above [3], wherein the compound (B) is a compound further having an aromatic group which may be substituted.
[5] The sealing material for an organic EL display element according to any one of the above [1] to [4], which has a viscosity of 5 mPa·s or more and 50 mPa·s or less at 25° C. and 20 rpm as measured with an E-type viscometer.
[6] The sealing material for an organic EL display element according to any one of the above [1] to [5], which is used for coating by an inkjet method.
[7] The sealing material for an organic EL display element according to any one of [1] to [6] above, which is used for forming a sealing layer in an organic EL display device having a structure in which an organic EL display element, a first inorganic material film, a sealing layer, and a second inorganic material film are laminated in this order.
[8] The sealing material for an organic EL display element according to any one of [1] to [7] above, which is used as the filler in a sealing structure using a dam material and a filler.
[9] A cured product obtained by curing the sealing material for an organic EL display element according to any one of [1] to [8] above.
[10] An organic EL display element;
a sealing layer that covers the organic EL display element;
wherein the sealing layer contains the cured product according to [9] above.

According to the present invention, it is possible to provide a sealing material for organic EL display elements that has an excellent balance of viscosity, plasma resistance, and refractive index when cured.

1 is a cross-sectional view showing a configuration example of an organic EL display device according to an embodiment.

Below, an embodiment of the present invention will be described with reference to the drawings. In all drawings, similar components are given the same reference symbols and descriptions will be omitted as appropriate. In this embodiment, each component may be used alone or in combination of two or more types. In addition, "~" indicating a numerical range indicates greater than or equal to or less than, and includes both the upper limit and the lower limit.

［上記一般式（１）中、Ｒ_１は水素原子またはメチル基を表し、＊は結合位置を表す。］ <Sealing material for organic EL display elements>
(Compound (A))
In this embodiment, the sealing material for an organic EL display element (hereinafter, simply referred to as "sealant") contains a compound (A) having a (meth)acrylthio group represented by the following general formula (1). The sealing material of this embodiment has an excellent balance of viscosity, plasma resistance, and refractive index when cured.

[In the above general formula (1), R ₁ represents a hydrogen atom or a methyl group, and * represents a bonding position.]

From the viewpoint of increasing the refractive index of the cured product of the sealing material, it is preferable that compound (A) is a compound having two or more (meth)acrylthio groups.

［上記一般式（２）中、Ｒ_１は一般式（１）の定義と同義であり、Ｒ_２は置換されてもよい脂肪族基、置換されてもよい脂環族基、置換されてもよい芳香族基または置換されてもよい複素環基を表し、上記脂肪族基および上記脂環族基は、酸素原子または硫黄原子を有してもよく、ｎは１以上の整数を示す。］ An example of the compound (A) is a compound represented by the following general formula (2).

[In the above general formula (2), _R1 has the same definition as in general formula (1), _R2 represents an optionally substituted aliphatic group, an optionally substituted alicyclic group, an optionally substituted aromatic group, or an optionally substituted heterocyclic group, the aliphatic group and the alicyclic group may have an oxygen atom or a sulfur atom, and n represents an integer of 1 or more.]

From the viewpoint of reducing the viscosity of the encapsulating material, R ₂ preferably has 1 to 20 carbon atoms, more preferably has 1 to 12 carbon atoms, and further preferably has 1 to 10 carbon atoms.

From the viewpoint of adjusting the polymerization rate of the sealing material and increasing the refractive index of the cured product of the sealing material, it is preferable that n in the general formula (2) is 2 or more. There is no upper limit for n, but it can be, for example, 12 or less, 6 or less, or 3 or less.

From the viewpoint of increasing the refractive index of the cured product of the encapsulating material and improving the plasma resistance of the cured product of the encapsulating material, it is preferable that _R2 in general formula (2) is an optionally substituted aliphatic group and has a sulfur atom.

The sealing material for an organic EL display element of the present embodiment may contain only one type of compound (A) or may contain multiple types of compounds (A).
From the viewpoint of increasing the refractive index of the cured product of the encapsulant and improving the plasma resistance of the cured product of the encapsulant, the encapsulant for an organic EL display element of this embodiment preferably contains multiple types of compounds (A) having different values of n in general formula (2).

［上記一般式（３）中、Ｒ_２およびｎはそれぞれ一般式（２）のＲ_２およびｎの定義と同様である。］ The compound of general formula (2) is produced, for example, from a thiol compound represented by general formula (3) and a (meth)acrylic acid halide by dehalogenation and dehydrogenation.

[In the above general formula (3), _R2 and n are defined as _R2 and n in general formula (2), respectively.]

The thiol compound represented by general formula (3) may have, in addition to a mercapto group, for example, a hydroxyl group.

Specific examples of the thiol compound represented by the general formula (3) are listed below. Specific examples of _R2 in the general formula (2) include groups derived from the following compounds.

Among the thiol compounds represented by the general formula (3), specific examples of monothiol compounds having one thiol group include methyl mercaptan, ethyl mercaptan, propyl mercaptan, butyl mercaptan, amyl mercaptan, hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, undecyl mercaptan, dodecyl mercaptan, tridecyl mercaptan, tetradecyl mercaptan, cetyl mercaptan, octadecyl mercaptan, allyl mercaptan, 2-butene-1-thiol, 1-butene-4-thiol, methallyl mercaptan, 1-pentenyl mercaptan, 2-i-pentenyl mercaptan, oleyl mercaptan, cyclopentyl mercaptan, cyclohexyl mercaptan, cyclopentyl mercaptan, ethyl methyl mercaptan, cycloheptyl mercaptan, 3-methylcyclopentyl methyl mercaptan, 2-methylcyclohexyl mercaptan, 3-methylcyclohexyl mercaptan, 4-methylcyclohexyl mercaptan, 3-methylcyclohexyl methyl mercaptan, 1-cyclopentyl mercaptan, 2-cyclohexenyl mercaptan, β-cyclohexyl ethyl mercaptan, 2,2,6,6-tetramethylcyclohexyl mercaptan, ε-cyclohexyl amyl mercaptan, cholesteryl mercaptan, furfuryl mercaptan, methylfurfuryl mercaptan, 2-mercaptothiophene, 3-mercaptothiophene, 2-ethyl-3-mercaptothiophene, thiophenol, thiocresol, ethylthiophenol, 2,4-thioxylene thiophenol, 2,5-thioxyleneol, propylthiophenol, allylthiophenol, 2-allyl-4-methylthiophenol, phenylthiophenol, chlorothiophenol, bromothiophenol, iodothiophenol, nitrothiophenol, trinitrothiophenol, dinitrothiophenol, nitrobromothiophenol, nitrochlorothiophenol, methylsulfonylthiophenol, benzenethiol, benzyl mercaptan, nitrobenzyl mercaptan, α-phenylethyl mercaptan, β-phenylethyl mercaptan, α-phenylpropyl mercaptan, γ-phenylpropyl mercaptan, β-phenylpropyl mercaptan, β-phenyl-i-propyl mercaptan, D-β-phenylbutyl mercaptan, ε-phenylamyl mercaptan, mercaptan, α,β-diphenylethyl mercaptan, methylbenzyl mercaptan, 2-nitro-p-tolyl mercaptan, α-(o-tolyl)benzyl mercaptan, α-(p-tolyl)benzyl mercaptan, chlorobenzyl mercaptan, dichlorobenzyl mercaptan, bromobenzyl mercaptan, α-phenyl-p-chlorobenzyl mercaptan, 3-hydroxy-5-methylbenzyl mercaptan, cinnamyl mercaptan, β-γ-diphenylallyl mercaptan, 4,4'-dichlorobenzhydryl mercaptan, triphenylmethyl mercaptan, α-thionaphthol, β-thionaphthol, 4-chloro-α-thionaphthol, 4-bromo-α-thionaphthol, 1-nitro-β-thionaphthol, 4-nitro-α-thionaphthol, and the like.

Among the thiol compounds represented by the general formula (3), specific examples of polythiol compounds having two or more thiol groups include:
Methanedithiol, 1,2-ketanedithiol, 1,1-propanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 2,2-propanedithiol, 1,6-hexanedithiol, 1,2,3-propanetrithiol, 1,1-cyclohexanedithiol, 1,2-cyclohexanedithiol, 2,2-dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane-1,2-dithiol, 2- Methylcyclohexane-2,3-dithiol, bicyclo[2,2,1]hepta-exo-cis-2,3-dithiol, 1,1-bis(mercaptomethyl)cyclohexane, thiomalic acid bis(2-mercaptoethyl ester), 2,3-dimercaptosuccinic acid (2-mercaptoethyl ester), 2,3-dimercapto-1-propanol (2-mercaptoacetate), 2,3-dimercapto-1-propanol (3-mercaptoethyl ester), aliphatic polythiols such as 1,2-dimercaptopropyl methyl ether, 2,3-dimercaptopropyl methyl ether, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, bis(2-mercaptoethyl)ether, ethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), trimethylolpropane bis(2-mercaptoacetate), trimethylolpropane bis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), and pentaerythritol tetrakis(3-mercaptopropionate), as well as halogen-substituted aliphatic polythiols such as chlorine-substituted and bromine-substituted products thereof;
1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1,2-bis(mercaptoethyl)benzene, 1,3-bis(mercaptoethyl)benzene, 1,4-bis(mercaptoethyl)benzene, 1,2-bis(mercaptomethyleneoxy)benzene, 1,3-bis(mercaptomethyleneoxy)benzene, 1,4-bis(mercaptomethyleneoxy)benzene, 1,2-bis(mercaptoethyleneoxy)benzene, 1,3-bis(mercaptoethyleneoxy)benzene, 1,4-bis(mercaptoethyleneoxy)benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercapto Mercaptobenzene, 1,2,3-tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyl)benzene, 1,2,3-tris(mercaptoethyl)benzene, 1,2,4-tris(mercaptoethyl)benzene, 1,3,5-tris(mercaptoethyl)benzene, 1,2,3-tris(mercaptomethyleneoxy)benzene, 1,2,4-tris(mercaptomethyleneoxy)benzene, 1,3,5-tris(mercaptomethyleneoxy)benzene, 1,2,3-tris(mercaptoethyleneoxy)benzene, 1,2,4-tris(mercaptoethyleneoxy)benzene, 1,3,5-tris(mercaptoethyleneoxy)benzene, 1,2,3,4-tetramercaptobenzene, 1,2,3,5-tetramercaptobenzene, 1, 2,4,5-tetramercaptobenzene, 1,2,3,4-tetrakis(mercaptomethyl)benzene, 1,2,3,5-tetrakis(mercaptomethyl)benzene, 1,2,4,5-tetrakis(mercaptomethyl)benzene, 1,2,3,4-tetrakis(mercaptoethyl)benzene, 1,2,3,5-tetrakis(mercaptoethyl)benzene, 1,2,4,5-tetrakis(mercaptoethyl)benzene, 1,2,3,4-tetrakis(mercaptomethyleneoxy)benzene, 1,2,3,5-tetrakis(mercaptomethyleneoxy)benzene, 1,2,3,4-tetrakis(mercaptoethyleneoxy)benzene, 1,2,3,5-tetrakis(mercaptoethyleneoxy)benzene, 1,2,4,5-tetrakis(mercapto ethyleneoxy)benzene, 2,2'-dimercaptobiphenyl, 4,4'-thiobis-benzenethiol, 4,4'-dimercaptobiphenyl, 4,4'-dimercaptobibenzyl, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol, 2,6-naphthalenedithiol, 2,7-naphthalenedithiol, 2,4-dimethylbenzene-1,3-dithiol, 4,5-dimethylbenzene-1,3-dithiol, 9,10-anthracenedimethanethiol, 1,3-di(p-methoxyphenyl)propane-2,2-dithiol, 1,3-diphenylpropane-2,2-dithiol, phenylmethane-1,1-dithiol, 2,4-di(p-mercaptophenyl)pentane, aromatic polythiols such as bis(4-mercaptophenyl)sulfide;
halogen-substituted aromatic polythiols such as chlorine-substituted aromatic polythiols and bromine-substituted aromatic polythiols, such as 2,5-dichlorobenzene-1,3-dithiol, 1,3-di(p-chlorophenyl)propane-2,2-dithiol, 3,4,5-tribromo-1,2-dimercaptobenzene, and 2,3,4,6-tetrachloro-1,5-bis(mercaptomethyl)benzene;
Heterocycle-containing polythiols such as 2-methylamino-4,6-dithiol-sym-triazine, 2-ethylamino-4,6-dithiol-sym-triazine, 2-amino-4,6-dithiol-sym-triazine, 2-morpholino-4,6-dithiol-sym-triazine, 2-cyclohexylamino-4,6-dithiol-sym-triazine, 2-methoxy-4,6-dithiol-sym-triazine, 2-phenoxy-4,6-dithiol-sym-triazine, 2-thiobenzeneoxy-4,6-dithiol-sym-triazine, 2-thiobutyloxy-4,6-dithiol-sym-triazine, 3,4-thiophenedithiol, and bismuthiol;
1,2-bis(mercaptomethylthio)benzene, 1,3-bis(mercaptomethylthio)benzene, 1,4-bis(mercaptomethylthio)benzene, 1,2-bis(mercaptoethylthio)benzene, 1,3-bis(mercaptoethylthio)benzene, 1,4-bis(mercaptoethylthio)benzene, 1,2,3-tris(mercaptomethylthio)benzene, 1,2,4-tris(mercaptomethylthio)benzene, 1,3,5-tris(mercaptomethylthio)benzene, 1,2,3-tris(mercaptoethylthio)benzene, 1,2,4-tris(mercaptomethylthio)benzene, Polythiols derived from nuclear alkylation products of aromatic compounds such as tris(mercaptoethylthio)benzene, 1,3,5-tris(mercaptoethylthio)benzene, 1,2,3,4-tetrakis(mercaptomethylthio)benzene, 1,2,3,5-tetrakis(mercaptomethylthio)benzene, 1,2,4,5-tetrakis(mercaptomethylthio)benzene, 1,2,3,4-tetrakis(mercaptoethylthio)benzene, 1,2,3,5-tetrakis(mercaptoethylthio)benzene, and 1,2,4,5-tetrakis(mercaptoethylthio)benzene;
bis(mercaptomethyl)sulfide, bis(mercaptoethyl)sulfide, bis(mercaptopropyl)sulfide, bis(mercaptomethylthio)methane, bis(2-mercaptoethylthio)methane, bis(3-mercaptopropylthio)methane, 1,2-bis(mercaptomethylthio)ethane, 1,2-bis(2-mercaptoethylthio)ethane, 1,2-bis(3-mercaptopropyl)ethane, 1,3-bis(mercaptomethylthio)propane, 1,3-bis(2-mercaptoethylthio)propane, 1,3-bis(3-mercaptopropylthio)propane, 1,2,3-tris(mercaptomethylthio)propane, Aliphatic polythiols such as 1,2,3-tris(2-mercaptoethylthio)propane, 1,2,3-tris(3-mercaptopropylthio)propane, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, bis(2,3-dimercaptopropyl)sulfide, 2,5-dimercapto-1,4-dithiane, bis(mercaptomethyl)disulfide, bis(mercaptoethyl)disulfide, bis(mercaptopropyl)disulfide, and thioglycolic acid esters and mercaptopropionic acid esters thereof;
Hydroxymethyl sulfide bis(2-mercaptoacetate), hydroxymethyl sulfide bis(3-mercaptopropionate), hydroxyethyl sulfide bis(2-mercaptoacetate), hydroxyethyl sulfide bis(3-mercaptopropionate), hydroxypropyl sulfide bis(2-mercaptoacetate), hydroxypropyl sulfide bis(3-mercaptopropionate), hydroxymethyl disulfide bis(2-mercaptoacetate), hydroxymethyl disulfide bis(3-mercaptopropionate), hydroxyethyl disulfide bis(2-mercaptoacetate), hydroxyethyl disulfide bis(3-mercaptopropionate), hydroxypropyl disulfide bis(2-mercaptoacetate), hydroxypropyl disulfide bis(3-mercaptopropionate), 2-mercaptoethyl ether bis(2-mercaptoacetate), 2-mercaptoethyl esters of aliphatic polythiols such as thiodiethyl ether bis(3-mercaptopropionate), 1,4-dithiane-2,5-diol bis(2-mercaptoacetate), 1,4-dithiane-2,5-diol bis(3-mercaptopropionate), thiodiglycolic acid bis(2-mercaptoethyl ester), thiodipropionic acid bis(2-mercaptoethyl ester), 4,4-thiodibutyric acid bis(2-mercaptoethyl ester), dithioglycolic acid bis(2-mercaptoethyl ester), dithiodipropionic acid bis(2-mercaptoethyl ester), 4,4-dithiodibutyric acid bis(2-mercaptoethyl ester), thiodiglycolic acid bis(2,3-dimercaptopropyl ester), thiodipropionic acid bis(2,3-dimercaptopropyl ester), dithioglycolic acid bis(2,3-dimercaptopropyl ester), dithiodipropionic acid bis(2,3-dimercaptopropyl ester);
2-mercaptoethanol, 3-mercapto-1,2-propanediol, glycerin di(mercaptoacetate), 1-hydroxy-4-mercaptocyclohexane, 2,4-dimercaptophenol, 2-mercaptohydroquinone, 4-mercaptophenol, 3,4-dimercapto-2-propanol, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3-butanediol, pentaerythritol tris(3-mercaptopropionate), pentaerythritol mono(3-mercaptopropionate), pentaerythritol bis(3-mercaptopropionate), pentaerythritol tris(thioglycolate), pentaerythritol Polythiols such as rupentakis (3-mercaptopropionate), hydroxymethyl-tris (mercaptoethylthiomethyl) methane, 1-hydroxyethylthio-3-mercaptoethylthiobenzene, 4-hydroxy-4'-mercaptodiphenyl sulfone, 2- (2-mercaptoethylthio) ethanol, dihydroxyethyl sulfide mono (3-mercaptopropionate), dimercaptoethane mono (saltylate), hydroxyethylthiomethyl-tris (mercaptoethylthiomethyl) methane, 2,2'- ((3-mercaptopropane-1,2-diyl) bis (sulfanediyl)) bis (ethane-1-thiol), 3,3'-thiobis (2- ((2-mercaptoethyl) thio) propane-1-thiol);
Examples include:
Further examples include halogen-substituted products such as chlorine-substituted and bromine-substituted products of these.

(Compound (B))
The sealing material for an organic EL display element of the present embodiment may further contain a compound (B). The compound (B) is a (meth)acrylic group-containing compound (excluding the above-mentioned compound (A)).
In this specification, the term "(meth)acryloyl group" refers to at least one of an acryloyl group and a methacryloyl group, the term "(meth)acrylic" refers to at least one of an acrylic group and a methacrylic group, and the term "(meth)acrylate" refers to at least one of an acrylate group and a methacrylate group.

Specific examples of (meth)acrylic compounds having a (meth)acryloyl group include monofunctional mono(meth)acrylic compounds, difunctional di(meth)acrylic compounds, and trifunctional or higher polyfunctional (meth)acrylic compounds.

Specific examples of mono(meth)acrylic compounds include isobornyl(meth)acrylate, dicyclopentanyl(meth)acrylate, 3,3,5-trimethylcyclohexyl(meth)acrylate, 4-tertiarybutylcyclohexyl(meth)acrylate, dicyclopentenyloxyethyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, isobutyl(meth)acrylate, t-butyl(meth)acrylate, isooctyl(meth)acrylate, 2-methoxyethyl(meth)acrylate, methoxytriethylene glycol(meth)acrylate, 2-ethoxyethyl(meth)acrylate, (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydixylethyl (meth)acrylate, ethyl diglycol (meth)acrylate, cyclic trimethylolpropane formal mono (meth)acrylate, imide (meth)acrylate, isoamyl (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 alcohol, aryl (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, Examples of the acrylates include methylphenoxyethyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, tribromophenyl (meth)acrylate, ethoxylated tribromophenyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, an ethylene oxide adduct of 2-phenoxyethyl (meth)acrylate, a propylene oxide adduct of 2-phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-methacryloyloxymethylcyclohexene oxide, and 3-(meth)acryloyloxymethylcyclohexene oxide.
Specific product names and sources of mono(meth)acrylic compounds include ethoxylated orthophenylphenol acrylate (NK Ester A-LEN-10, manufactured by Shin-Nakamura Chemical Co., Ltd.), m-phenoxybenzyl acrylate (Light Acrylate POB-A, manufactured by Kyoeisha Chemical Co., Ltd.), and the like.

Specific examples of the di(meth)acrylic compound include di(meth)acrylates of diols and di(meth)acrylates of (poly)alkylene glycols.
Specific product names and sources of di(meth)acrylic compounds include 1,6-hexanediol diacrylate (NK Ester A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,6HX-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,9-nonanediol diacrylate (NK Ester 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 (NK Ester A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), neopentyl glycol diacrylate (NK Ester A-NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate NP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethylene glycol diacrylate (SR206NS, manufactured by Arkema), polyethylene glycol diacrylate (NK Ester A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), polypropylene glycol diacrylate (NK Ester APG-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), (manufactured by Kyoeisha Chemical Co., Ltd.), tricyclodecane dimethanol diacrylate (also known as dimethylol-tricyclodecane diacrylate) (NK Ester A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,3-butanediol dimethacrylate (NK Ester BG, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,4-butanediol dimethacrylate (NK Ester BD, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,6-hexanediol dimethacrylate acrylate (NK Ester HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,9-nonanediol dimethacrylate (NK Ester NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,10-decanediol dimethacrylate (NK Ester DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,12-dodecanediol diacrylate (SR262, manufactured by Sartomer Corporation), neopentyl glycol dimethacrylate (NK Ester NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.), and the like.

Specific product names and sources of polyfunctional (meth)acrylic compounds are as follows:
trifunctional (meth)acrylic compounds such as trimethylolpropane triacrylate (NK ESTER A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate TMP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethoxylated trimethylolpropane triacrylate (NK ESTER A-TMPT-EO, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated glycerin triacrylate (NK ESTER A-GLY-6E, manufactured by Shin-Nakamura Chemical Co., Ltd.), and propoxylated glycerin triacrylate (NK ESTER A-GLY-3P, manufactured by Shin-Nakamura Chemical Co., Ltd.);
tetrafunctional (meth)acrylic compounds such as pentaerythritol tetraacrylate (NK Ester A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated pentaerythritol tetraacrylate (NK Ester ATM-4E, manufactured by Shin-Nakamura Chemical Co., Ltd.), and ditrimethylolpropane tetraacrylate (NK Ester AD-TMP-L, manufactured by Shin-Nakamura Chemical Co., Ltd.);
Pentafunctional (meth)acrylic compounds such as dipentaerythritol pentaacrylate (M-402, manufactured by Toagosei Co., Ltd.);
hexafunctional (meth)acrylic compounds such as dipentaerythritol hexaacrylate (GM66G0H, manufactured by Kokusei Chemical Industry Co., Ltd.);
etc.

From the viewpoint of increasing the refractive index of the cured product of the sealing material, it is preferable that compound (B) is a compound further having an aromatic group which may be substituted. Specific examples of the aromatic group which may be substituted in compound (B) include those derived from the compounds exemplified above as the thiol compound represented by general formula (3), which are aromatic groups which may be substituted.

From the viewpoint of increasing the strength of the cured product of the sealing material, the total amount of compound (A) and compound (B) is preferably 70 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and even more preferably 99 mass% or more, based on the total composition of the sealing material of this embodiment.

The amount of compound (A) is preferably 50 parts by mass or more and 100 parts by mass or less, and more preferably 60 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the total of compound (A) and compound (B).
Furthermore, the amount of compound (A) can be, for example, 70 parts by mass or more and 100 parts by mass or less, or 80 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass in total of compound (A) and compound (B).

The amount of compound (B) is preferably 0 parts by mass or more and 50 parts by mass or less, and more preferably 0 parts by mass or more and 40 parts by mass or less, relative to 100 parts by mass in total of compound (A) and compound (B).
Further, the amount of compound (B) can be, for example, 0 parts by mass or more and 30 parts by mass or less, for example, 0 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass in total of compound (A) and compound (B).

(Polymerization initiator)
The sealing material of the present embodiment may further include a polymerization initiator. From the viewpoint of stably forming a cured product at low temperatures, the polymerization initiator is preferably a photopolymerization initiator, which is a compound that generates radicals or acids when irradiated with ultraviolet rays or visible light.
Examples of the photopolymerization initiator include acylphosphine oxide initiators, oxyphenylacetic acid ester initiators, benzoylformic acid initiators, and hydroxyphenyl ketone initiators.

Specific examples of photopolymerization initiators 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, isopropyl benzoin ether, isobutyl benzoin ether, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, and 4-dimethylaminobenzoic acid ether. ethyl, 4-dimethylaminobenzoate isoamyl, 4,4'-di(t-butylperoxycarbonyl)benzophenone, 3,4,4'-tri(t-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra(t-hexylperoxycarbonyl)benzophenone, 3,3'-di(methoxycarbonyl)-4,4'-di(t-butylperoxycarbonyl)benzophenone, 3,4'-di(methoxycarbonyl)-4,3'-di(t-butylperoxycarbonyl)benzphenone benzophenone, 4,4'-di(methoxycarbonyl)-3,3'-di(t-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, trichloromethyl)-s-triazine, 4-[p-N,N-di(ethoxycarbonylmethyl)]-2,6-di(trichloromethyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(4'-methoxyphenyl)-s-triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzthiazole, 2-mercaptobenzothiazole, 3,3'-carbonylbis(7-diethylaminocoumarin), 2-(o-chlorophenoxy ...2-(o-chlorophenoxy)-s-triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzthiazole, 2-mercaptobenzothiazole, 2-(o-chlorophenoxy)-s-triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzthiazole, 2-mercaptobenzothiazole, 2-(o 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 Imidazole, 3-(2-methyl-2-dimethylaminopropionyl)carbazole, 3,6-bis(2-methyl-2-morpholinopropionyl)-9-n-dodecylcarbazole, bis(η5-2,4-cyclopentadiene-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, oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester, oxy-phenyl-acetic acid Acid 2-[2-hydroxy-ethoxy]-ethyl ester, methyl benzoylformate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphinic acid ester, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone-1-(O-acetyloxime), and the like can be mentioned.

In order to improve the curing properties of the sealing material, the photopolymerization initiator is 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, oxy-phenyl-acetic acid. It is preferable that the compound is one or more compounds selected from the group consisting of 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester, oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, methyl benzoylformate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), and 2,4,6-trimethylbenzoyldiphenylphosphinic acid ester.

Specific product names and sources of photopolymerization initiators include Irgacure 184, Irgacure 651, Irgacure 127, Irgacure 1173, Irgacure 500, Irgacure 2959, Irgacure 754, Irgacure MBF, Irgacure TPO (all manufactured by BASF), Omnirad TPO H (manufactured by IGM Resins), etc.

From the viewpoint of improving the curing properties of the sealing material, the content of the polymerization initiator is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 1 mass% or more, and even more preferably 2 mass% or more, based on the total composition of the sealing material.

In addition, from the viewpoint of suppressing discoloration of the sealing material, the content of the polymerization initiator is preferably 10 mass% or less, more preferably 8 mass% or less, even more preferably 6 mass% or less, and even more preferably 5 mass% or less, relative to the total composition of the sealing material.

(Other ingredients)
The encapsulant of the present embodiment may contain, as components other than those described above (other components), one or more components selected from the group consisting of a tackifier, a filler, a curing accelerator, a plasticizer, a surfactant, a heat stabilizer, an antioxidant, a flame retardant, an antistatic agent, an antifoaming agent, a leveling agent, and an ultraviolet absorber.
The content of the other components is preferably 5 mass % or less, and more preferably 1 mass % or less, based on the total composition of the encapsulant.

From the viewpoint of improving the thermal stability of the encapsulating material, the encapsulating material preferably contains a thermal stabilizer.
As the heat stabilizer, a hindered phenol compound can be used.
Examples of the hindered phenol compound include dibutylhydroxytoluene (also known as 2,6-bis(1,1-dimethylethyl)-4-methylphenol) (product name BHT, manufactured by Wako Pure Chemical Industries, Ltd.), 3,5-di-tert-butyl-4-hydroxytoluene, pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (product name IRGANOX1010, manufactured by BASF; product name Adeka STAB AO-60, manufactured by ADEKA Corporation), and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (product name IRGANOX1076, manufactured by BASF Corporation).
From the viewpoint of further improving the thermal stability of the sealing material, the sealing material preferably contains at least one of dibutylhydroxytoluene and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] as a thermal stabilizer.

As the antioxidant, a phosphorus-based antioxidant can be used.
Examples of the phosphorus-based antioxidant include phosphite esters, such as 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite (product name: Adeka STAB HP-10, manufactured by ADEKA CORPORATION) and tris(2,4-di-t-butylphenyl)phosphite (product name: IRGAFOS168, manufactured by BASF Corporation).

(Characteristics of sealing material)
The properties of the sealing material of the present embodiment are not limited, but it is preferably liquid from the viewpoint of suitability for application by an inkjet method or the like.

In addition, in an embodiment, from the viewpoint of stably forming a sealing layer, the sealing material is preferably a sealing material used for application, and more preferably a sealing material used for application by an inkjet method.

The viscosity of the sealing material measured at 25° C. and 20 rpm using an E-type viscometer is preferably 5 mPa·s or more, more preferably 8 mPa·s or more, and even more preferably 10 mPa·s or more, from the viewpoint of improving inkjet ejection properties.
From the viewpoint of improving the inkjet ejection properties, the viscosity of the sealing material is preferably 50 mPa·s or less, more preferably 40 mPa·s or less, and further preferably 30 mPa·s or less.

(Method of manufacturing sealing material)
The method for producing the encapsulant is described below. The method for producing the encapsulant is not limited, and includes, for example, mixing the compound (A), appropriately the compound (B), and other components, such as various additives that are added as necessary.
Examples of methods for mixing the components include a method in which the components are uniformly kneaded using various known kneading machines, such as a planetary mixer, a homodisper, a universal mixer, a Banbury mixer, a kneader, a two-roll mill, a three-roll mill, an extruder, or the like, either alone or in combination, at room temperature or with heating, under normal pressure, reduced pressure, pressurized or in an inert gas stream, or the like.

<Cured Product>
The cured product of the sealing material of this embodiment is obtained by curing the sealing material of this embodiment.
For example, the cured product of the encapsulant of the present embodiment can be obtained by applying the encapsulant of the present embodiment onto a substrate and curing the applied encapsulant. For application, a known method such as an inkjet method, screen printing, or dispenser application can be used.

The sealing material applied to the substrate can be cured by drying. The sealing material can be dried, for example, by heating to a temperature at which compound (A) does not polymerize. There are no limitations on the shape of the cured product obtained by curing the sealing material, and it can be, for example, a film or layer.

The sealant applied to the substrate can also be photocured. Examples of methods for photocuring the sealant include methods of curing the sealant by irradiating it with light using a light source such as a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an extra-high pressure mercury lamp, an excimer laser, a chemical lamp, a black light lamp, a microwave excited mercury lamp, a metal halide lamp, a sodium lamp, a halogen lamp, a xenon lamp, an LED lamp such as a UV-LED, a fluorescent lamp, sunlight, or an electron beam irradiation device.

The refractive index (nd) of the cured product of the encapsulant of this embodiment at room temperature (25°C) at d-line (wavelength 587.6 nm) is preferably 1.60 or more, more preferably 1.61 or more, even more preferably 1.62 or more, even more preferably 1.63 or more, even more preferably 1.64 or more, and even more preferably 1.65 or more. There is no upper limit to the refractive index, but it can be, for example, 2.00 or less, 1.90 or less, or 1.80 or less. The refractive index of the encapsulant after curing can be measured with an Abbe refractometer.

The cured product of the encapsulant can be used as an encapsulating material for encapsulating organic EL display elements. The cured product of the encapsulant of this embodiment has a high refractive index and excellent plasma resistance, making it preferable as an encapsulating material.

<Organic EL display device>
The organic EL display device of the present embodiment includes an organic EL display element and a sealing layer containing the cured product of the sealing material of the present embodiment. By including the sealing layer, the organic EL display element disposed on the substrate is sealed by the sealing layer, so that the intrusion of moisture into the organic EL display element can be sufficiently prevented, and the performance and durability of the organic EL display element can be maintained at a high level.

The sealing layer may be coated with an inorganic material film. Also, the organic EL display element disposed on the substrate may be coated with an inorganic material film in advance before being sealed with the sealing layer.

Specifically, in an organic EL display device having a structure in which an organic EL display element, a first inorganic material film, a sealing layer, and a second inorganic material film are laminated in this order, the sealing material of this embodiment is used to form the sealing layer.

FIG. 1 is a cross-sectional view showing an example of the configuration of an organic EL display device according to this embodiment.
In the organic EL display device 100 shown in FIG. 1, an organic EL display element 10 is disposed on a substrate 50 , and the surface of the organic EL display element 10 is covered with a first inorganic material film 21 .
The organic EL display element 10 covered with the first inorganic material film 21 is sealed with a first sealing layer 22 .
The surface of the first sealing layer 22 is further covered with a second inorganic material film 23 .
The first sealing layer 22 covered with the second inorganic material film 23 is further sealed by a second sealing layer 24 .
A surface protection layer 25 is provided on the surface of the second sealing layer 24 .

The organic EL display device 100 may have a top emission structure or a bottom emission structure.

The material of the substrate 50 is not limited, and various substrates such as a glass substrate, a silicon substrate, a plastic substrate, etc. 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.

Examples of inorganic materials constituting the first inorganic material film 21 and the second inorganic material film 23 include silicon nitride (SiN _x ), silicon oxide (SiO _x ), aluminum oxide (Al ₂ O ₃ ), etc. The inorganic material film may be a single layer or a laminate of multiple types of layers.

Methods for coating with the first inorganic material film 21 and the second inorganic material film 23 include, for example, sputtering and electron cyclotron resonance plasma CVD when the inorganic material film is made of silicon nitride or silicon oxide.

Of these, the sputtering method can be carried out, for example, using a single or mixed gas such as argon or nitrogen as a carrier gas under conditions of room temperature, power of 50 to 1000 W, and pressure of 0.001 to 0.1 Torr.

In addition, the electron cyclotron resonance plasma CVD method can be performed, for example, using a mixed gas of _SiH4 and _O2 or a mixed gas of _SiH4 and _N2 under 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.

Because the sealing layer of this embodiment has excellent plasma resistance, even if an inorganic material film is formed on its surface by plasma processing such as electron cyclotron resonance plasma CVD, the resin layer is less likely to deteriorate and damage to the organic EL light-emitting element is suppressed.

The thickness of the first inorganic material film 21 and the second inorganic material film 23 is not limited, but from the viewpoint of improving the barrier performance, it is, for example, 0.01 to 10 μm, preferably 0.1 to 5 μm.

Methods for obtaining a sealing layer include coating and curing a sealing material. An inkjet method can be used for coating. The sealing material can also be applied to a surface by screen printing, dispenser coating, inkjet printing, slit coating, spray coating, or other methods.

The thickness of the sealing layer is not limited, but from the viewpoint of improving sealing performance and flexibility performance, it is, for example, 0.1 to 50 μm, and preferably 1 to 20 μm.

One method for sealing an organic EL display element is to form a dam around the organic EL display element using a high-viscosity curable resin (dam material), and then pour a low-viscosity curable resin (fill material) into the dam and allow it to harden. In such a sealing structure using a dam material and a fill material, the sealing material of this embodiment can be used as the fill material. The sealing material of this embodiment has a reduced viscosity and excellent fluidity, making it suitable for use as a fill material.

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

(Preparation of sealing material)
First, the materials used in the following examples are listed.

チオ化合物Ａ２：特許２７０８６０７号公報の実施例３の記載にしたがい調製された下記式の化合物

チオ化合物Ａ３：特開平９－３２４０２３号公報の合成例６の記載にしたがい調製された下記式の化合物

チオ化合物Ａ４：特許２７０８６０７号公報の実施例１の４，４'－チオビス－ベンゼンチオール２５．０部（０．１０モル）をベンジルメルカプタン２４．８部（０．２０モル）に代えた以外は特許２７０８６０７号公報の実施例１と同様の操作をすることにより調整された下記式の化合物

チオ化合物Ａ５：特許２７０８６０７号公報の実施例１の記載にしたがい調製された下記式の化合物

As compound (A), the following thio compounds A1 to A5 were used.
Thio Compound A1: A compound of the following formula, prepared according to the description in Example 2 of JP-B-7-91262:

Thio Compound A2: A compound of the following formula, prepared according to the description in Example 3 of Japanese Patent No. 2708607:

Thio Compound A3: A compound of the following formula prepared according to Synthesis Example 6 of JP-A-9-324023.

Thio Compound A4: A compound of the following formula prepared by the same procedure as in Example 1 of Japanese Patent No. 2708607, except that 25.0 parts (0.10 moles) of 4,4'-thiobis-benzenethiol in Example 1 of Japanese Patent No. 2708607 was replaced with 24.8 parts (0.20 moles) of benzyl mercaptan.

Thio Compound A5: A compound of the following formula prepared according to the description in Example 1 of Japanese Patent No. 2708607

As the compound (B), the following (meth)acrylic compounds B1 to B4 were used.
(Meth)acrylic compound B1: ethoxylated orthophenylphenol acrylate, product name NK Ester A-LEN-10, manufactured by Shin-Nakamura Chemical Co., Ltd. (Meth)acrylic compound B2: m-phenoxybenzyl acrylate, product name Light Acrylate POB-A, manufactured by Kyoeisha Chemical Co., Ltd. (Meth)acrylic compound B3: benzyl acrylate, product name Viscoat #160, manufactured by Kyoeisha Chemical Co., Ltd. (Meth)acrylic compound B4: 1,9-nonanediol diacrylate, product name Light Acrylate 1,9-ND-A, manufactured by Kyoeisha Chemical Co., Ltd.

The thermal stabilizer used was pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (product name: Adeka STAB AO-60, manufactured by ADEKA Corporation). The photoradical initiator used was 2,4,6-trimethylbenzoyldiphenylphosphine oxide (product name: Omnirad TPO H, manufactured by IGM Resins Corporation).

The components were mixed so as to obtain the composition shown in Table 1, thereby obtaining a liquid sealing material.
The units of the compound (A) and compound (B) in Table 1 are parts by mass of compound (A) or compound (B) relative to 100 parts by mass of the total of compound (A) and compound (B). The units of the compounded compositions of the heat stabilizer and photoradical initiator in Table 1 are % by mass relative to the total composition of the encapsulant.

The physical properties of the resulting encapsulant were measured using the following methods. The measurement results are shown in Table 1.

(viscosity)
The viscosity of the obtained sealing material was measured using an E-type viscometer (LV DV-II+ Pro, manufactured by BROOKFIELD) at 25° C. and 20 rpm. The evaluation was performed according to the following criteria. The results are shown in Table 1.
○: 5 to 50 mPa·s
×: Less than 5 mPa·s or more than 50 mPa·s

(Refractive Index)
The refractive index of the cured film obtained by curing the obtained encapsulant was evaluated by the following method.
A 100 μm thick Teflon (registered trademark) sheet was used as a mold, and the mold was placed on top of a transparent polyethylene terephthalate (PET) film. The encapsulant obtained by the above method was poured into the mold, and a transparent PET film was placed on top of the mold, sandwiching the encapsulant between the two transparent PET films. The encapsulant was then cured using a UV-LED with a wavelength of 395 nm at an illuminance of 1000 mW/cm ² and an accumulated light quantity of 1500 mJ/cm ² to obtain a cured film.
The refractive index (nd) of the cured film after curing at room temperature (25° C.) with d-line (wavelength 587.6 nm) was measured using an Abbe refractometer (DR-M4, manufactured by Atago Co., Ltd.). Evaluation was performed according to the following criteria. The results are shown in Table 1.
◯: 1.60 or more ×: less than 1.60

(Plasma resistance)
As the plasma resistance, element damage in a plasma treatment process using a parallel plate type electron cyclotron resonance plasma CVD apparatus was evaluated by the following method.
The encapsulant obtained by the above method was introduced into an inkjet cartridge DMC-11610 (manufactured by Fujifilm Dimatix Corp.). The inkjet cartridge was set into an inkjet device DMP-2831 (manufactured by Fujifilm Dimatix Corp.), and after adjusting the discharge state, the encapsulant was applied to a glass substrate in a size of 15 mm x 15 mm so that the thickness after curing was 10 μm.
The resulting coating film was placed in a box with nitrogen flowing and adjusted to room temperature (25°C), left to stand for 5 minutes, and then irradiated with a UV-LED having a wavelength of 395 nm at an illuminance of 1000 mW/ ^cm2 and an accumulated light quantity of 1500 mJ/ ^cm2 to form a cured film.
On the surface of the cured film, an inorganic material film ( _SiNx film) was deposited to a thickness of 1 μm using a parallel plate type electron cyclotron resonance plasma CVD apparatus under conditions of an output of 100 W and a cured film surface temperature of 100° C.
The obtained sample was placed in a thermo-hygrostat at 85° C. and 85% humidity for 240 hours, after which the appearance was observed. Evaluation was performed according to the following criteria. The results are shown in Table 1.
◯: No whitening ×: Whitening

As shown in Table 1, the sealing material and its cured product obtained in each example had excellent effect of suppressing element damage due to plasma exposure, as well as a high refractive index and a low viscosity suitable for application.

This application claims priority based on Japanese Patent Application No. 2020-191965, filed on November 18, 2020, the disclosure of which is incorporated herein in its entirety.

REFERENCE SIGNS LIST 10 Organic EL display element 21 First inorganic material film 22 First sealing layer 23 Second inorganic material film 24 Second sealing layer 25 Surface protective layer 50 Substrate 100 Organic EL display device

Claims (9)

The composition contains a compound (A) having a (meth)acrylthio group represented by the following general formula (1) ,
Further containing a compound (B) having a (meth)acrylic group (excluding the compound (A)),
The sealing material for an organic electroluminescence display element , wherein the content of the compound (A) is 50 parts by mass or more per 100 parts by mass of the total of the compound (A) and the compound (B).

[In the above general formula (1), R ₁ represents a hydrogen atom or a methyl group, and * represents a bonding position.] The sealing material for organic EL display elements according to claim 1, wherein the compound (A) is a compound having two or more (meth)acrylthio groups. 3. The sealing material for an organic EL display element according to claim 1 , wherein the compound (B) is a compound further having an aromatic group which may be substituted. 4. The sealing material for an organic EL display element according to claim 1 , wherein the viscosity measured with an E-type viscometer at 25° C. and 20 rpm is 5 mPa·s or more and 50 mPa·s or less. The sealing material for an organic EL display element according to any one of claims 1 to 4 , which is used for coating by an inkjet method. The sealing material for an organic EL display element according to any one of claims 1 to 5, which is used for forming a sealing layer in an organic EL display device having a structure in which an organic EL display element, a first inorganic material film, a sealing layer, and a second inorganic material film are laminated in this order. The sealing material for an organic EL display element according to any one of claims 1 to 6 , which is used as a filler material in a sealing structure using a dam material and a filler material. A cured product obtained by curing the sealing material for an organic EL display element according to any one of claims 1 to 7 . An organic EL display element;
a sealing layer that covers the organic EL display element;
The organic electroluminescence display device according to claim 8, wherein the sealing layer comprises the cured product according to claim 8 .

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