Photosensitive composition, cured product thereof, organic electroluminescent display device, and method for producing photosensitive composition

Abstract

To provide a composition capable of improving reliability of an organic EL display device.SOLUTION: A photosensitive composition contains a polymerizable compound and a photopolymerization initiator and has a concentration of C2-40 hydroxy compounds of 0.01 ppm or more and 12,000 ppm or less. The C2-40 hydroxy compounds may include a polyhydroxy compound.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photosensitive composition, a cured product thereof, an organic electroluminescent display device, and a method for producing the photosensitive composition. [Background technology]

[0002] Organic electroluminescence display devices (hereinafter also referred to as organic EL display devices) have attracted attention because they are capable of emitting light with high brightness. However, the organic EL elements in organic EL display devices are prone to degradation due to oxygen and moisture, and there is a problem that the degradation leads to a decrease in the light-emitting characteristics. To solve this problem, technology to seal the organic EL elements and prevent degradation is being considered.

[0003] Patent Document 1 describes a sealant for organic EL devices that contains a polymerizable compound and a polymerization initiator, has a viscosity of 5 to 50 mPa s at 25°C, a surface tension of 15 to 35 mN / m at 25°C, and has a water content of 1000 ppm or less at 25°C after being left to stand for 24 hours in an environment of 25°C and 50% RH.

[0004] Patent Document 2 describes a resin composition suitable for use as an encapsulant for organic EL devices, which contains a (meth)acrylate compound (A) having an aromatic hydrocarbon skeleton, a cyclic (meth)acrylate compound (B) and a polymerization initiator (C). Here, the cyclic (meth)acrylate compound (B) is at least one (meth)acrylate compound selected from the group consisting of (meth)acrylate compounds having an aromatic hydrocarbon skeleton, which are (meth)acrylate compounds different from compound (A), (meth)acrylate compounds having an alicyclic hydrocarbon skeleton, and (meth)acrylate compounds having a heterocyclic skeleton.

[0005] Patent Document 3 describes a sealant for organic electroluminescence display elements that contains (A) an alkanediol di(meth)acrylate having from 4 to 20 carbon atoms and (B) a photopolymerization initiator, and in which the amount of hydrophilic functional groups per (meth)acrylate is in the range of 4.80 to 7.60 mmol / g. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-040872 A [Patent Document 2] JP 2014-193970 A [Patent Document 3] International Publication No. 2019 / 203071 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, various compositions intended for sealing organic EL elements have been proposed so far. However, technology is advancing at a rapid pace, and further improvements are required for compositions intended for sealing organic EL elements. For example, there is a demand for improved reliability (longer life) of organic EL display devices through improvements in compositions.

[0008] The present invention has been made in view of the above circumstances. One object of the present invention is to provide a composition capable of improving the reliability of an organic EL display device. [Means for solving the problem]

[0009] The present inventors have completed the invention provided below and have solved the above problems.

[0010] According to the present invention, A photosensitive composition comprising a polymerizable compound and a photopolymerization initiator, A photosensitive composition having a concentration of a hydroxy compound having 2 to 40 carbon atoms of 0.01 ppm to 12,000 ppm. is provided.

[0011] Further, according to the present invention, A cured product of the above photosensitive composition is provided.

[0012] Further, according to the present invention, An organic electroluminescence display device in which an organic electroluminescence element is sealed with the above cured product. is provided.

[0013] Further, according to the present invention, A method for producing the photosensitive composition, comprising the steps of: A method for producing a photosensitive composition, comprising: a pretreatment step of pretreating a raw material polymerizable compound by at least one of the following methods (i) to (iii); and a mixing step of mixing the polymerizable compound treated in the pretreatment step with a photopolymerization initiator. is provided.

[0014] (i) The raw polymerizable compound is subjected to a devolatilization treatment for 10 minutes or more in an environment of 10° C. to 100° C. and 1000 Pa or less. (ii) Distilling the raw polymerizable compound. (iii) The raw polymerizable compound is treated with an acid chloride. Effect of the Invention

[0015] According to the present invention, there is provided a composition capable of improving the reliability of an organic EL device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail.

[0017] In the description of groups (atomic groups) in this specification, when a description is made without specifying whether the group is substituted or unsubstituted, the description includes both groups having no substituents and groups having a substituent. For example, an "alkyl group" includes not only an alkyl group having no substituents (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). In this specification, the term "(meth)acrylic" refers to a concept that includes both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate." In this specification, the term "hydroxy compound" is a general term for compounds having a hydroxy group, and includes alcohol compounds and phenol compounds. Furthermore, unless otherwise specified, the term "hydroxy compound" includes both monohydroxy compounds such as monools and polyhydroxy compounds such as polyols.

[0018] <Photosensitive composition> The photosensitive composition of the present embodiment contains a polymerizable compound and a photopolymerization initiator. In the photosensitive composition of this embodiment, the concentration of the hydroxy compound having 2 to 40 carbon atoms is 0.01 ppm or more and 12,000 ppm or less. The photosensitive composition of the present embodiment is preferably used for encapsulating an organic electroluminescence element, that is, the photosensitive composition of the present embodiment is preferably used for encapsulating an organic EL element to produce an organic EL display device.

[0019] The present inventors have investigated what causes the conventional reliability of organic EL elements to be impaired from the viewpoint of a composition intended for sealing an organic EL element. As a result of the investigation, the present inventors found that a hydroxy compound (such as an alcohol compound or a phenol compound) contained in the composition and remaining in a small amount even after sealing the organic EL element seems to corrode the organic EL element. They also found that the hydroxy compound seems to be a hydroxy compound with a relatively large carbon number derived from a polymerizable compound, which is one of the raw materials of the composition. Based on this finding, the present inventors have newly prepared a composition having a low amount of hydroxyl compounds in the entire composition, for example by reducing the content of hydroxyl compounds in the raw polymerizable compound, and have been able to improve the reliability of the organic EL element by sealing the organic EL element with this composition.

[0020] The photosensitive composition of the present embodiment is produced by selecting appropriate raw materials and carrying out an appropriate production process. Examples of "appropriate raw materials" include using raw materials that contain a small amount of hydroxy compounds as impurities, and preparing the photosensitive composition substantially without solvent, using as little as possible a solvent that is likely to contain hydroxy compounds.

[0021] Examples of the "appropriate manufacturing process" include at least one of the following pretreatments of the raw material: (i) devolatilizing the raw material polymerizable compound (such as a (meth)acrylate compound), (ii) distilling the raw material polymerizable compound, and (iii) reacting the raw material polymerizable compound with an acid chloride. These will be explained in detail below.

[0022] (polymerizable compound) The polymerizable compound is not particularly limited as long as it is a compound that can be polymerized by active species generated from a photopolymerization initiator described below. In the present embodiment, the polymerizable compound preferably contains a (meth)acrylate compound and / or an epoxy compound, and more preferably a (meth)acrylate compound. Each will be described below.

[0023] (Meth)acrylate compounds The polymerizable compound preferably contains a polyfunctional (meth)acrylate compound. By using a polyfunctional (meth)acrylate compound, the photocurability tends to be improved. The polyfunctional (meth)acrylate compound may contain, for example, a difunctional to hexafunctional, preferably a difunctional to tetrafunctional (meth)acrylate compound. In terms of the balance of various performances, the polyfunctional (meth)acrylate compound preferably contains a difunctional (meth)acrylate compound, that is, a di(meth)acrylate compound.

[0024] The polymerizable compound preferably contains one or more selected from the group consisting of polyfunctional (meth)acrylates and monofunctional (meth)acrylates, and more preferably contains a polyfunctional (meth)acrylate and a monofunctional (meth)acrylate. By using a polyfunctional (meth)acrylate and a monofunctional (meth)acrylate in combination, it becomes possible to adjust the polymerization property and the physical properties of the cured film. In terms of balance of various performances, when a polyfunctional (meth)acrylate and a monofunctional (meth)acrylate are used in combination, preferably 40% by mass or more of the total polymerizable compounds, more preferably 50% by mass or more of the total polymerizable compounds are polyfunctional (meth)acrylate. Preferably 70% by mass or more of the total polymerizable compounds, more preferably 80% by mass or more of the total polymerizable compounds, and most preferably 90% by mass or more of the total polymerizable compounds are polyfunctional (meth)acrylate. Preferably 100% by mass or less of the total polymerizable compounds, more preferably 98% by mass or less of the total polymerizable compounds, and most preferably 95% by mass or less of the total polymerizable compounds are polyfunctional (meth)acrylate. The total polymerizable compounds are preferably 100 parts by mass in total of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate. Just to be clear, the polymerizable compound may contain only a monofunctional (meth)acrylate, so long as good performance is achieved.

[0025] Specific examples of the polyfunctional (meth)acrylate compound include bifunctional (meth)acrylates, trifunctional (meth)acrylates, and tetrafunctional or higher (meth)acrylates.

[0026] Examples of the bifunctional (meth)acrylate include the following. Bis(1-(meth)acryloxy-2-hydroxypropyl)phthalate, bis(2-(meth)acryloxyethyl)phosphate, bis((meth)acryloxy-2-hydroxypropyloxy)diethylene glycol, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di-(3-(meth)acryloxy-2-hydroxypropyl)ether, 1,4-butanediol di(meth)acrylate, 1,3-butanediol bis((meth)acryloxypropionate), 1,4-butanediol bis((meth)acryloxypropionate) onate), 2-butene-1,4-diol di(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, 2,2-dimethyl-1,3-propanediol di(meth)acrylate, dipentaerythritol ether di(meth)acrylate, diphenolic acid di-(3-(meth)acryloxy-2-hydroxypropyl)ether, dipropylene glycol di(meth)acrylate, 7,7,9-trimethyl-3,13-dioxo- 3,14-dioxa-5,12-diazahexadecane-1,16-diol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,2-ethanediol di(meth)acrylate, 1,2-ethanediol bis((meth)acryloxypropionate), 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,4-phenylenedi(meth)acrylate, 1-phenyl-1,2-ethanediol di(meth)acrylate, poly Triethylene glycol di(meth)acrylate, 2,2,4-trimethyl-1,3-pentanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, and bifunctional (meth)acrylates having a bisphenol structure.

[0027] Examples of bifunctional (meth)acrylates having a bisphenol structure include the following. Ethoxylated bisphenol A dimethacrylate, bisphenol A di(meth)acrylate, bisphenol A di-(3-(meth)acryloxyethyl) ether, bisphenol A di-(3-(meth)acryloxy-2-hydroxypropyl) ether, propoxylated bisphenol A di(meth)acrylate, tetrabromobisphenol A di-(3-(meth)acryloxy-2-hydroxypropyl) ether, tetrachlorobisphenol A di-(3-(meth)acryloxy-2-hydroxypropyl) ether. As the bifunctional (meth)acrylate having a bisphenol structure, a di(meth)acrylate having two (meth)acrylic groups at the end of a bisphenol skeleton via an oxyalkylene structure is preferable. The oxyalkylene structure may have a hydroxyl group. Among the bifunctional (meth)acrylates having a bisphenol structure, a compound represented by the following general formula (A) is preferable.

[0028] [ka]

[0029] In formula (A), the definitions of each group are as follows. R 1 and R 1 R' represents a hydrogen atom or a methyl group. 1 and R 1 ' may be the same or different. R 2 and R 2 R' represents an alkylene group. The alkylene group may have a hydroxyl group. 2 and R 2 ' may be the same or different. R 3 and R 3 R' represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 3 and R 3' may be the same or different. p and q each represent a number from 1 to 20. p and q may be the same or different.

[0030] In the general formula (A), R 2 and R 2 It is preferable that ' is an alkylene group not having a hydroxyl group. R 1 and R 1 R' is preferably a methyl group. 2 and R 2 R' is preferably an alkylene group having 1 to 12 carbon atoms, more preferably an ethylene group. The alkylene group preferably does not have a hydroxyl group. 3 and R 3 is preferably a methyl group. p+q is preferably 15 or less, more preferably 10. p+q is preferably 1 to 8, more preferably 4.

[0031] Examples of trifunctional (meth)acrylates include the following. 1,2,4-butanetriol tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, polyoxypropyl trimethylolpropane tri(meth)acrylate, silicone tri(meth)acrylate, 1,3,5-tri(meth)acryloylhexahydro-s-triazine, trimethylolethane tri(meth)acrylate, 1,1,1-trimethylolpropane tri(meth)acrylate, 1,2,3-trimethylolpropane tri(meth)acrylate, 1,1,1-trimethylolpropane tris((meth)acryloxypropionate), 1,2,3-trimethylolpropane tris((meth)acryloxypropionate), tris-(2-(meth)acryloxyethyl)isocyanurate.

[0032] Examples of tetrafunctional or higher (meth)acrylates include the following. Pentaerythritol tetra(meth)acrylate, pentaerythritol tetrakis((meth)acryloxypropionate). Among the polyfunctional (meth)acrylate compounds, difunctional (meth)acrylates are preferred. Among the difunctional (meth)acrylates, at least one member selected from the group consisting of difunctional (meth)acrylates having a bisphenol structure, 1,12-dodecanediol di(meth)acrylate, and dimethylol-tricyclodecane di(meth)acrylate is preferred.

[0033] Specific examples of the monofunctional (meth)acrylate compound include the following.

[0034] Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, cyclohexyl (meth)acrylate, lauryl (meth)acrylate, n-octyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, ethoxylated-o-phenylphenol (meth)acrylate. Among the monofunctional (meth)acrylates, ethoxylated-o-phenylphenol (meth)acrylate is preferred.

[0035] Incidentally, when a (meth)acrylate compound is used as the polymerizable compound, a small amount of a hydroxy compound corresponding to the (meth)acrylate compound used is usually contained in the photosensitive composition. Specifically, when a (meth)acrylate compound is used as the polymerizable compound, a small amount of a hydroxy compound in which a part or all of the (meth)acryloyloxy group (HC=CH-C(=O)-O-, or HC=C(CH3)-C(=O)-O-) of the (meth)acrylate compound has been converted to a hydroxy group (HO-) may be contained in the photosensitive composition. When a polyfunctional (meth)acrylate compound is used as the polymerizable compound, a small amount of a polyhydroxy compound may be contained in the photosensitive composition. In addition, various hydroxy compounds (monol, polyol, phenol compounds, etc.) may be contained in the photosensitive composition depending on the starting material used in synthesizing the (meth)acrylate compound and the structure of the (meth)acrylate compound.

[0036] As described above, the term "hydroxy compound" is a general term for compounds having a hydroxy group, and includes alcohol compounds and phenol compounds. Furthermore, unless otherwise specified, the term "hydroxy compound" includes both monohydroxy compounds and polyhydroxy compounds. Regarding "hydroxy compounds", it is preferable that the concentration of hydroxy compounds having 2 to 40 carbon atoms, particularly the concentration of polyhydroxy compounds having 2 to 40 carbon atoms, is 0.01 ppm or more and 12,000 ppm or less. Regarding "hydroxy compounds," it is preferable that the concentration of hydroxy compounds believed to be derived from polymerizable compounds, particularly the concentration of polyhydroxy compounds derived from polymerizable compounds, be 0.01 ppm or more and 12,000 ppm or less.

[0037] Examples of hydroxy compounds that are measured by gas chromatography and are considered to be derived from polymerizable compounds include the following: Examples of hydroxy compounds considered to be derived from 1,12-dodecanediol di(meth)acrylate include 1,12-dodecanediol (carbon number: 12) and 1,12-dodecanediol mono(meth)acrylate (acrylate has 15 carbon atoms, methacrylate has 16 carbon atoms). Examples of hydroxy compounds that are considered to be derived from dimethylol-tricyclodecane di(meth)acrylate include phenylphenol (having 12 carbon atoms) and biphenylyloxyethanol (having 14 carbon atoms). Examples of the monohydroxy compound include one or more members selected from the group consisting of 1,12-dodecanediol mono(meth)acrylate, phenylphenol, and biphenylyloxyethanol. An example of a polyhydroxy compound is 1,12-dodecanediol. The "hydroxy compound" preferably has 5 to 30 carbon atoms, more preferably has 8 to 25 carbon atoms, most preferably has 10 to 20 carbon atoms, and even more preferably has 12 to 16 carbon atoms. It is preferable to adjust the concentration of hydroxy compounds, particularly polyhydroxy compounds having 2 to 40 carbon atoms, to 0.01 ppm or more and 12,000 ppm or less.

[0038] Epoxy compounds The polymerizable compound may include an epoxy compound. The epoxy compound may be monofunctional or polyfunctional. In addition, a monofunctional epoxy compound and a polyfunctional epoxy compound may be used in combination.

[0039] Examples of monofunctional epoxy compounds include 4-tert-butylphenyl glycidyl ether, m,p-cresyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, etc. Of course, the monofunctional epoxy compounds are not limited to these.

[0040] Examples of the polyfunctional epoxy compound include compounds having two or more epoxy groups in one molecule, selected from compounds known as epoxy resins.Specific examples of the polyfunctional epoxy compound include phenol novolac epoxy resins, cresol novolac epoxy resins, cresol naphthol epoxy resins, biphenyl epoxy resins, biphenyl aralkyl epoxy resins, phenoxy resins, naphthalene skeleton epoxy resins, diallyl bisphenol A epoxy resins, bisphenol A diglycidyl ether epoxy resins, bisphenol F diglycidyl ether epoxy resins, bisphenol S diglycidyl ether epoxy resins, glycidyl ether epoxy resins, cresol novolac epoxy resins, aromatic polyfunctional epoxy resins, aliphatic epoxy resins, aliphatic polyfunctional epoxy resins, alicyclic epoxy resins, and polyfunctional alicyclic epoxy resins.

[0041] Regarding the epoxy compound, various hydroxy compounds (monol, polyol, phenol compounds, etc.) may be contained in the photosensitive composition depending on the starting material used in synthesizing the epoxy compound and the structure of the epoxy compound.

[0042] From the viewpoint of volatilizing the hydroxy compound while leaving (not volatilizing) the polymerizable compound in the volatilization treatment described later, it is preferable that the polymerizable compound contains one that is difficult to volatilize. Specifically, the polymerizable compound preferably contains one having a molecular weight of 210 or more and 2000 or less, more preferably one having a molecular weight of 300 or more and 2000 or less, even more preferably one having a molecular weight of 300 or more and 1000 or less, and particularly preferably one having a molecular weight of 300 or more and 600 or less. That is, it is preferable that the photosensitive composition of this embodiment contains one that fits the above molecular weight from among the above-mentioned (meth)acrylate compounds (particularly polyfunctional (meth)acrylates) and epoxy compounds. More specifically, it is preferable that the photosensitive composition of this embodiment contains 50% by mass or more of the polymerizable compound that fits the above molecular weight in the total polymerizable compounds. Just to be clear, the use of polymerizable compounds not falling within the above molecular weight range is not excluded in this embodiment.

[0043] (Photopolymerization initiator) The photopolymerization initiator is not particularly limited as long as it is capable of polymerizing the above-mentioned polymerizable compound. As an example, the photopolymerization initiator preferably includes a photoradical polymerization initiator. The photoradical polymerization initiator is preferably used in combination with the above-mentioned (meth)acrylate compound.

[0044] Examples of photoradical polymerization initiators include benzophenone and its derivatives, benzil and its derivatives, anthraquinone and its derivatives, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, benzoin derivatives such as benzil dimethyl ketal, diethoxyacetophenone, 4-tert-butyltrichloroacetophenone and other acetophenone derivatives, 2-dimethylaminoethyl benzoate, p-dimethylaminoethyl benzoate, etc. diphenyl disulfide, thioxanthone and its derivatives, camphorquinone, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-bromoethyl ester, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-methyl ester, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid chloro camphorquinone derivatives such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, α-aminoalkylphenone derivatives such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, benzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyldiethoxyphosphine oxide, 2,4,6-trimethylbenzoyldimethoxyphenylphosphine oxide, acylphosphine oxide derivatives such as 2,4,6-trimethylbenzoyldiethoxyphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; phenyl-glyoxylic acid-methyl ester; oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester; and oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester.

[0045] As another example, the photopolymerization initiator preferably includes a cationic photopolymerization initiator. The cationic photopolymerization initiator is preferably used in combination with the above-mentioned epoxy compound.

[0046] Examples of photocationic polymerization initiators include sulfonium salts such as triphenylsulfonium trifluoromethanesulfonate and tris(4-t-butylphenyl)sulfonium trifluoromethanesulfonate; diazonium salts such as p-nitrophenyldiazonium hexafluorophosphate; ammonium salts; phosphonium salts; iodonium salts such as diphenyliodonium trifluoromethanesulfonate and (tricumyl)iodonium tetrakis(pentafluorophenyl)borate; and quinones. Examples of the photocationic polymerization initiator include diazides, diazomethanes such as bis(phenylsulfonyl)diazomethane, sulfonic acid esters such as 1-phenyl-1-(4-methylphenyl)sulfonyloxy-1-benzoylmethane and N-hydroxynaphthalimide-trifluoromethanesulfonate, disulfones such as diphenyldisulfone, and triazines such as tris(2,4,6-trichloromethyl)-s-triazine and 2-(3,4-methylenedioxyphenyl)-4,6-bis(trichloromethyl)-s-triazine. Of course, the photocationic polymerization initiator is not limited to these.

[0047] The photopolymerization initiators can be used alone or in combination of two or more. As the photopolymerization initiator, a photoradical polymerization initiator is preferable. As the photoradical polymerization initiator, an acylphosphine oxide derivative is preferable because it can be cured only by visible light of 390 nm or more when curing, and can be cured without damaging the organic EL element. Among the acylphosphine oxide derivatives, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is most preferable because it can be cured only by light of 395 nm or more without reducing the transmittance of visible light when used as an organic EL display device. As the 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, "Omnirad TPO" manufactured by IGM Resins can be mentioned.

[0048] The content of the photopolymerization initiator is preferably 0.05 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 8 parts by mass or less, still more preferably 1 part by mass or more and 5 parts by mass or less, and particularly preferably 2 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the polymerizable compound. By using an appropriate amount of the photopolymerization initiator, it is easy to ensure sufficient transparency of the encapsulant while obtaining sufficient sensitivity / curing speed.

[0049] (Other optional ingredients) The photosensitive composition of the present embodiment may or may not contain other components for adjusting performance, in addition to the polymerizable compound and the photopolymerization initiator. Other components include antioxidants, surfactants, sensitizers, etc.

[0050] It is not excluded that the photosensitive composition of this embodiment contains an organic solvent. However, from the viewpoint of setting the concentration of the hydroxy compound to an appropriate value, it is preferable that the photosensitive composition of this embodiment does not substantially contain an organic solvent, or contains only a small amount of the organic solvent. Specifically, the amount of the organic solvent is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.1% by mass or less in the entire photosensitive composition. Ideally, the photosensitive composition of this embodiment does not substantially contain an organic solvent. Organic solvents that are easily used industrially often contain hydroxy compounds as impurities, and therefore, by preparing a photosensitive composition substantially without using an organic solvent, it is easy to prepare a photosensitive composition having an appropriate concentration of a hydroxy compound.

[0051] (Additional and supplementary explanations regarding various values) As described above, the concentration of the hydroxy compound having 2 to 40 carbon atoms may be 0.01 ppm to 12000 ppm. This concentration is preferably 1 ppm to 11000 ppm, more preferably 10 ppm to 11000 ppm, even more preferably 100 ppm to 11000 ppm, and particularly preferably 1000 ppm to 11000 ppm. Basically, the lower the concentration of the hydroxy compound having 2 to 40 carbon atoms, the better. However, in consideration of the production cost, the concentration of the hydroxy compound is usually 0.01 ppm or more.

[0052] As described above, the hydroxy compound in the composition may be derived from the raw polymerizable compound. For example, when the polymerizable compound is a polyfunctional compound such as a polyfunctional (meth)acrylate compound, the hydroxy compound may typically include a polyhydroxy compound. In this respect, the concentration of the polyhydroxy compound in the photosensitive composition of the present embodiment is preferably 0.01 ppm or more and 12000 ppm or less, more preferably 1 ppm or more and 11000 ppm or less, even more preferably 10 ppm or more and 1000 ppm or less, particularly preferably 15 ppm or more and 500 ppm or less, and particularly preferably 40 ppm or more and 100 ppm or less, in order to improve the reliability of the organic EL device. The concentration of the monohydroxy compound in the photosensitive composition of the present embodiment is preferably 0.01 ppm or more and 12000 ppm or less, from the viewpoint of improving the reliability of the organic EL device, more preferably 1 ppm or more and 11000 ppm or less, even more preferably 10 ppm or more and 11000 ppm or less, particularly preferably 100 ppm or more and 11000 ppm or less, and particularly preferably 1000 ppm or more and 11000 ppm or less.

[0053] From another perspective, considering that the hydroxy compound in the composition may be derived from the polymerizable compound as a raw material, the composition may contain a hydroxy compound having 2 carbon atoms or a certain amount of more carbon atoms (for example, a hydroxy compound having 3 to 40 carbon atoms, specifically, a hydroxy compound having 4 to 35 carbon atoms). By reducing the concentration of such a hydroxy compound to about the above numerical range, the reliability of the organic EL element can be further improved.

[0054] The dissolved oxygen concentration of the photosensitive composition of this embodiment is preferably 0.1 mg / L to 5 mg / L, more preferably 0.5 mg / L to 3 mg / L, and even more preferably 0.7 mg / L to 2 mg / L. The water concentration of the photosensitive composition of the present embodiment is preferably 1 ppm or more and 50 ppm or less, more preferably 3 ppm or more and 40 ppm or less, and further preferably 5 ppm or more and 30 ppm or less. By sufficiently reducing the dissolved oxygen concentration and water concentration in the photosensitive composition, the reliability of the organic EL display device can be further improved.

[0055] The viscosity of the photosensitive composition of the present embodiment is preferably from 3 mPa·s to 50 mPa·s, more preferably from 5 mPa·s to 30 mPa·s. This level of viscosity improves the ease of ejection when applying an inkjet method, the ease of film formation, and the like. The viscosity can be measured, for example, using a cone-plate viscometer (manufactured by Eiko Seiki Co., Ltd., product number: HB DV3T, etc.) under conditions of 25° C. and 200 to 250 rpm (preferably 250 rpm).

[0056] <Method for producing photosensitive composition> The photosensitive composition of the present embodiment can be produced by using the above-mentioned components and employing an appropriate production method. As an example, the photosensitive composition of the present embodiment can be produced through the following steps (1) to (5). (1) A pretreatment step for pretreating the raw polymerizable compound (hereinafter, also simply referred to as the "pretreatment step"). (2) A mixing step of mixing the polymerizable compound treated in the pretreatment step (1) with a photopolymerization initiator (hereinafter also simply referred to as the "mixing step"). (3) Dehydration process (4) Deoxidation process (5) Filtration process

[0057] Here, the pretreatment step (1) above can be at least any one of the following methods (i) to (iii). (i) The raw polymerizable compound is subjected to a devolatilization treatment for 10 minutes or more in an environment of 10° C. to 100° C. and 1000 Pa or less. (ii) Distilling the raw polymerizable compound. (iii) The raw polymerizable compound is treated with an acid chloride.

[0058] Each of the above steps will now be described.

[0059] (1) Pretreatment process The pretreatment step is carried out with the intention of reducing the concentration of hydroxy compounds having 2 to 40 carbon atoms contained in the raw polymerizable compound. By appropriately carrying out the pretreatment step, it is easy to produce a photosensitive composition in which the concentration of hydroxy compounds having 2 to 40 carbon atoms is 0.01 ppm to 12,000 ppm.

[0060] An example of the pretreatment step is (i) a step of subjecting the raw polymerizable compound to a devolatilization treatment for 10 minutes or more in an environment of 10° C. to 100° C. and 1000 Pa or less. By such a devolatilization treatment, the hydroxy compound (which usually has a lower molecular weight than the polymerizable compound itself) contained in the polymerizable compound is volatilized, and the amount of the hydroxy compound in the polymerizable compound can be reduced.

[0061] The temperature during devolatilization is preferably about 10°C or higher and 100°C or lower, and more preferably about 30°C or higher and 80°C or lower. The devolatilization time is preferably 10 minutes or more, and more preferably 10 minutes or more and 60 minutes or less. The pressure during devolatilization can be preferably 1000 Pa or less, and more preferably 1 Pa or more and 1000 Pa or less.

[0062] Devolatilization can be carried out on a laboratory scale, for example, by placing a stirrer in a flask and reducing the pressure by connecting a vacuum pump and a vacuum gauge. When heating the flask to more actively volatilize the volatile matter, it is preferable to use an oil bath. Devolatilization on a large scale can be carried out, for example, in a stainless steel pressure vessel equipped with a stirrer. Incidentally, in order to maintain an appropriate degree of vacuum, air bubbling (blowing air into the liquid) may be performed. This is because if the concentration of oxygen, which deactivates the polymerization active species, becomes too low, the polymerizable compound may polymerize.

[0063] Another example of the pretreatment step is (ii) a step of distilling the raw polymerizable compound. That is, the amount of the hydroxyl compound contained in the polymerizable compound can be reduced by utilizing the difference in boiling point / vapor pressure between the polymerizable compound itself (specifically, a (meth)acrylate compound and / or an epoxy compound) and the hydroxyl compound. The method of distillation is not particularly limited, and a general distillation technique may be appropriately used to reduce the amount of hydroxy compounds in the raw polymerizable compound.

[0064] As another example of the pretreatment step, there can be mentioned (iii) a step of treating the raw polymerizable compound with an acid chloride, in which the hydroxy compound in the raw polymerizable compound is reacted with the acid chloride to "cap" the hydroxy group of the hydroxy compound with the acid chloride, thereby reducing the concentration of the hydroxy compound.

[0065] The type of acid chloride is not particularly limited as long as the hydroxy group is simply capped with the acid chloride, but the acid chloride is preferably (meth)acrylic acid chloride, because it can "convert" the hydroxy compound into a polymerizable compound ((meth)acrylate compound).

[0066] In the treatment with acid chloride, various techniques known in the field of organic synthetic chemistry can be applied. For example, a basic catalyst may be used in the treatment with acid chloride. In addition, recovery of the monomer after the treatment with acid chloride and removal of excess acid chloride and catalyst can be performed, for example, by a suitable liquid separation operation.

[0067] From the viewpoint of ease of reducing the concentration of hydroxy compounds, the treatment of (ii) or (iii) is preferred, and the treatment of (iii) is more preferred. On the other hand, from the viewpoint of ease of industrial large-scale treatment, the treatment of (i) is preferred. Also, taking into consideration the reduction of impurities other than hydroxy compounds (e.g., hydrocarbons such as toluene), the treatment of (i) or (ii) is preferred. In the pretreatment step, only one of the above treatments (i) to (iii) may be performed, or two or more of the treatments may be performed. For example, by performing the treatment (i) after the treatment (ii) or (iii), the concentration of the hydroxy compounds can be reduced and the concentrations of impurities other than the hydroxy compounds can also be reduced.

[0068] (2)Mixing process In the mixing step, the polymerizable compound treated in the pretreatment step (1) and the photopolymerization initiator are mixed in appropriate amounts to obtain a mixture. The mixing method is not particularly limited, and the mixture can be stirred using a known stirrer.

[0069] (3) Dehydration process It is preferable to remove as much water as possible from the mixture obtained in (2) above. By carrying out the dehydration step, the water concentration of the photosensitive composition can be easily adjusted to 1 ppm or more and 50 ppm or less. The method for reducing the water content is not particularly limited, but examples thereof include the following methods. (i) A desiccant is used. The desiccant is separated by decantation or filtration after removing the moisture. The desiccant is not particularly limited as long as it does not affect the composition. Examples of the desiccant include polymer adsorbents (molecular sieves, synthetic zeolite, alumina, silica gel, etc.), inorganic salts (calcium chloride, anhydrous magnesium sulfate, quicklime, anhydrous sodium sulfate, anhydrous calcium sulfate, etc.), solid alkalis (sodium hydroxide, potassium hydroxide, etc.), etc. (ii) Heating under reduced pressure. (iii) Purifying by distillation under reduced pressure. (iv) An inert gas such as dry nitrogen or dry argon gas is blown through each component. (v) Freeze-drying.

[0070] As a method for reducing moisture, (i) a method using a desiccant is preferred from the viewpoints of simplicity and suppression of deterioration of components. As a desiccant, a polymer adsorbent is preferred. As a polymer adsorbent, a molecular sieve is preferred.

[0071] (4) Deoxidation process By carrying out the deoxidation step, the amount of dissolved oxygen in the mixture can be reduced. Then, the dissolved oxygen concentration in the photosensitive composition can be easily adjusted to 0.1 mg / L or more and 5 mg / L or less. The method for reducing the dissolved oxygen is not particularly limited, and examples thereof include the following methods. (i) Exposing the mixture to reduced pressure conditions. (ii) An inert gas such as dry nitrogen or dry argon gas is bubbled through the mixture. (iii) Exposure to low oxygen concentrations.

[0072] Incidentally, the amount of dissolved oxygen may be reduced by combining two or more of the above methods. For example, the method of combining (i) and (ii) may be used, that is, the amount of dissolved oxygen in the mixture may be reduced by blowing an inert gas such as dry nitrogen or dry argon gas into the mixture under reduced pressure conditions.

[0073] (5) Filtration process The mixture obtained through the above steps (1) to (4) is filtered using an appropriate filter. This allows the photosensitive composition of the present embodiment to be obtained. Although there are no particular limitations on the filter that can be used, it is preferable to use a filter with a pore size of 1 μm or less in order to obtain a photosensitive composition that meets the specifications required for sealing an organic EL device.

[0074] <Cured product, organic EL display device>

[0075] A cured product can be obtained by irradiating the photosensitive composition of the present embodiment with light. Furthermore, an organic EL display device can be produced by sealing an organic EL element with the photosensitive composition of the present embodiment.

[0076] The light source for curing the photosensitive composition is not particularly limited, and examples thereof include a halogen lamp, a metal halide lamp, a high-power metal halide lamp (containing indium, etc.), a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a xenon excimer lamp, a xenon flash lamp, and an LED.

[0077] The light irradiation dose is 100 mJ / cm 2 More than 8000mJ / cm 2 It is preferable that the concentration is less than 300 mJ / cm 2 More than 2000mJ / cm 2 It is more preferable that the irradiation dose is 100 mJ / cm. 2 By setting the irradiation dose at 8000 mJ / cm or more, the composition is sufficiently cured and sufficient sealing properties are easily obtained. 2 By doing the following, it is possible to prevent damage to the organic EL element.

[0078] Examples of methods for producing an organic EL display device include (i) forming a film (uncured film) of the photosensitive composition of this embodiment on the surface of a substrate on which an organic EL element is provided, and (ii) irradiating the film with light. In this way, the organic EL element can be sealed with the cured product of the photosensitive composition of this embodiment. As described above, by sealing the organic EL element with the cured product of the photosensitive composition of this embodiment, the reliability of the finally obtained organic EL display device can be improved. Incidentally, after the above (ii), an inorganic protective film such as SiN may be further provided on the surface of the cured product.

[0079] The above-mentioned film formation (i) is preferably performed by an inkjet method. In the manufacture of an organic EL display device, it is preferable to form a film by an inkjet method since it is necessary to uniformly form a film on a large-area substrate on which a plurality of organic EL elements are provided. In the film formation of (i) above, the film thickness is, for example, 1 μm to 15 μm, preferably 3 μm to 10 μm. By forming and curing a film having a thickness of 1 μm or more, it is easy to obtain a sufficient sealing ability as a sealing material. In addition, a film thickness of 15 μm or less leads to miniaturization of an organic EL display device and reduction in manufacturing costs.

[0080] Hereinafter, one aspect of an organic EL display device manufactured using the photosensitive composition of this embodiment as a sealant forming material will be described using a top emission type organic EL display device as an example. Just to be clear, the organic EL display device to which the photosensitive composition of this embodiment is applied is not limited to the top emission type. The organic EL display device may be a bottom emission type organic EL display device that irradiates the light generated in the organic EL layer from the substrate side.

[0081] A top-emission type organic EL display device includes an organic EL element, a sealing layer that seals the organic EL element, and a sealing substrate provided on the sealing layer.

[0082] An organic EL element has a structure in which, for example, an anode, an organic EL layer including a light-emitting layer, and a cathode are laminated in this order on a substrate.

[0083] Examples of the substrate for the organic EL element include a glass substrate, a silicon substrate, a plastic substrate, etc. Among these, one or more types of the group consisting of a glass substrate and a plastic substrate are preferred, and a glass substrate is more preferred.

[0084] As the anode, a conductive metal oxide film or a semitransparent metal thin film having a relatively large work function (preferably one having a work function of 4.0 eV or more) is generally used. Examples of the material for the anode include metal oxides such as indium tin oxide (ITO) and tin oxide, metals such as gold (Au), platinum (Pt), silver (Ag), and copper (Cu), or alloys containing at least one of these metals, and organic transparent conductive films such as polyaniline or its derivatives, and polythiophene or its derivatives. The anode can be formed of two or more layers if necessary. The thickness of the anode can be appropriately selected taking into consideration the electrical conductivity (and light transmittance in the case of a bottom emission type). The thickness of the anode is preferably 10 nm to 10 μm, more preferably 20 nm to 1 μm, and most preferably 50 nm to 500 nm. Methods for producing the anode include vacuum deposition, sputtering, ion plating, and plating. In the case of a top emission type, a reflective film for reflecting light irradiated to the substrate side may be provided under the anode.

[0085] The organic EL layer includes at least a light-emitting layer made of an organic material. The light-emitting layer contains a light-emitting material. Examples of the light-emitting material include organic materials (low molecular weight compounds or high molecular weight compounds) that emit fluorescence or phosphorescence. The light-emitting layer may further contain a dopant material. Examples of organic materials include dye-based materials, metal complex-based materials, polymer materials, etc. Dopant materials are materials that are doped into organic materials for the purpose of improving the luminous efficiency of the organic material, changing the luminous wavelength, etc. The thickness of the luminescent layer made of these organic materials and dopants that are doped as necessary is usually 2 nm or more and 200 nm or less.

[0086] Examples of dye-based materials include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, triphimanylamine derivatives, oxadiazole dimers, and pyrazoline dimers.

[0087] Examples of the metal complex-based materials include metal complexes having emission from triplet excited states, such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzothiazole zinc complexes, azomethyl zinc complexes, porphyrin zinc complexes, and europium complexes. Examples of the metal complexes include metal complexes having rare earth metals such as terbium (Tb), europium (Eu), and dysprosium (Dy), aluminum (Al), zinc (Zn), and beryllium (Be) as central metals, and having oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, and quinoline structures as ligands. Among these, metal complexes having aluminum (Al) as central metals and quinoline structures as ligands, and metal complexes having iridium (Ir) as central metals and pyridine ring compounds as ligands are preferred. Among metal complexes having aluminum (Al) as the central metal and a quinoline structure or the like as the ligand, tris(8-hydroxyquinolinato)aluminum is preferred. Among metal complexes having iridium (Ir) as the central metal and a pyridine ring compound or the like as the ligand, a compound (Ir(ppy)3+CBP) in which 4,4'-N,N'-dicarbazole-biphenyl (CBP) is doped with tris(2-phenylpyridine) (Ir(ppy)3) is preferred.

[0088] Examples of the polymeric material include polyparaphenylenevinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polymerized versions of the above-mentioned colorants and metal complex-based luminescent materials.

[0089] Among the above-mentioned light-emitting materials, materials that emit blue light include distyrylarylene derivatives, oxadiazole derivatives, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among the polymer materials, one or more selected from the group consisting of polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

[0090] Examples of materials that emit green light include quinacridone derivatives, coumarin derivatives, polyparaphenylenevinylene derivatives, polyfluorene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among polymer materials, one or more selected from the group consisting of polyparaphenylenevinylene derivatives and polyfluorene derivatives are preferred.

[0091] Examples of materials that emit red light include coumarin derivatives, thiophene ring compounds, polyparaphenylenevinylene derivatives, polythiophene derivatives, polyfluorene derivatives, and polymers thereof. Among these, polymer materials are preferred. Among polymer materials, one or more selected from the group consisting of polyparaphenylenevinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferred.

[0092] Examples of the dopant material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squarium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and pyridine ring compounds.

[0093] In addition to the light-emitting layer, the organic EL layer may appropriately include a layer provided between the light-emitting layer and the anode, and a layer provided between the light-emitting layer and the cathode. First, the layer provided between the light-emitting layer and the anode may include a hole injection layer that improves the efficiency of hole injection from the anode, and a hole transport layer that transports holes injected from the anode or the hole injection layer to the light-emitting layer. The layer provided between the light-emitting layer and the cathode may include an electron injection layer that improves the efficiency of electron injection from the cathode, and an electron transport layer that transports electrons injected from the cathode or the electron injection layer to the light-emitting layer.

[0094] Examples of materials for forming the hole injection layer include phenylamines such as 4,4',4''-tris{2-naphthyl(phenyl)amino}triphenylamine, starburst amines, phthalocyanines, oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminum oxide, amorphous carbon, polyaniline, and polythiophene derivatives.

[0095] Examples of materials constituting the hole transport layer include benzidine derivatives such as N,N'-diphenyl-N,N'-dinaphthylbenzidine, polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, polysiloxane derivatives having an aromatic amine in the side chain or main chain, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, polyaniline or a derivative thereof, polythiophene or a derivative thereof, polyarylamine or a derivative thereof, polypyrrole or a derivative thereof, poly(p-phenylenevinylene) or a derivative thereof, and poly(2,5-thienylenevinylene) or a derivative thereof.

[0096] When the hole injection layer or the hole transport layer has a function of blocking the transport of electrons, it is sometimes called an electron blocking layer.

[0097] Materials constituting the electron transport layer include oxadiazole derivatives, anthraquinodimethane or its derivatives, benzoquinone or its derivatives, naphthoquinone or its derivatives, anthraquinone or its derivatives, tetracyanoanthraquinodimethane or its derivatives, fluorenone derivatives, diphenyldicyanoethylene or its derivatives, diphenoquinone derivatives, 8-hydroxyquinoline or its derivatives, polyquinoline or its derivatives, polyquinoxaline or its derivatives, polyfluorene or its derivatives, etc. Examples of derivatives include metal complexes, etc. Among these, 8-hydroxyquinoline or its derivatives are preferred. Among 8-hydroxyquinoline or its derivatives, one or more of the group consisting of bis(2-methyl-8-quinolinolato)(p-phenylphenolato)aluminum and tris(8-hydroxyquinolinolato)aluminum are preferred, in that they can also be used as an organic material that emits fluorescence or phosphorescence and is contained in the light-emitting layer.

[0098] The electron injection layer may be, depending on the type of the light-emitting layer, an electron injection layer having a single layer structure of a calcium (Ca) layer, or a single layer structure of a layer formed of at least one of the group consisting of metals of Groups IA and IIA of the periodic table and having a work function of 1.5 eV to 3.0 eV, and oxides, halides, and carbonates of the metals, or an electron injection layer having a laminate structure of a layer formed of at least one of the group consisting of metals of Groups IA and IIA of the periodic table and having a work function of 1.5 eV to 3.0 eV, and oxides, halides, and carbonates of the metals, and a Ca layer. Examples of metals of Group IA of the periodic table and having a work function of 1.5 eV to 3.0 eV, or oxides, halides, and carbonates of the metals, include lithium (Li), lithium fluoride, sodium oxide, lithium oxide, and lithium carbonate. Examples of metals in Group IIA of the periodic table having a work function of 1.5 eV to 3.0 eV or oxides, halides, and carbonates thereof include strontium (Sr), magnesium oxide, magnesium fluoride, strontium fluoride, barium fluoride, strontium oxide, and magnesium carbonate.

[0099] When the electron transport layer or the electron injection layer has a function of blocking the transport of holes, the electron transport layer or the electron injection layer is sometimes called a hole blocking layer.

[0100] The cathode is preferably a transparent or semi-transparent material that has a relatively small work function (preferably one having a work function of less than 4.0 eV) and that allows easy injection of electrons into the light-emitting layer. Examples of the cathode material include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), aluminum (Al), scandium (Sc), vanadium (V), zinc (Zn), yttrium (Y), indium (In), cerium (Ce), samarium (Sm), europium (Eu), terbium (Tb), and tetrahydrofuran (Tc). Examples of the metal include metals such as tungsten (Tb) and ytterbium (Yb), alloys of two or more of the above metals, alloys of one or more of the above metals and one or more of gold (Au), silver (Ag), platinum (Pt), copper (Cu), chromium (Cr), manganese (Mn), titanium (Ti), cobalt (Co), nickel (Ni), tungsten (W) and tin (Sn), graphite or a graphite intercalation compound, and metal oxides such as ITO, IZO (Indium Zinc Oxide), and tin oxide.

[0101] The cathode may have a laminated structure of two or more layers. Examples of the laminated structure of two or more layers include a laminated structure of the above-mentioned metals, metal oxides, fluorides, and alloys thereof with metals such as Al, Ag, and Cr. The thickness of the cathode can be appropriately selected in consideration of electrical conductivity and durability. The thickness of the cathode is preferably 10 nm or more and 10 μm or less, more preferably 15 nm or more and 1 μm or less, and most preferably 20 nm or more and 500 nm or less. Examples of methods for producing the cathode include a vacuum deposition method, a sputtering method, and a lamination method in which a metal thin film is thermocompressed.

[0102] The layers provided between the light-emitting layer and the anode, and between the light-emitting layer and the cathode can be appropriately selected according to the performance required for the organic EL display device to be manufactured. For example, the organic EL element can have any of the layer configurations (i) to (xv) below. (i) Anode / hole transport layer / light emitting layer / cathode (ii) anode / light-emitting layer / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer / electron transport layer / cathode (iv) Anode / hole injection layer / light emitting layer / cathode (v) Anode / light-emitting layer / electron injection layer / cathode (vi) Anode / hole injection layer / light emitting layer / electron injection layer / cathode (vii) Anode / hole injection layer / hole transport layer / light emitting layer / cathode (viii) Anode / hole transport layer / light emitting layer / electron injection layer / cathode (ix) Anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode (x) Anode / hole injection layer / light emitting layer / electron transport layer / cathode (xi) Anode / light-emitting layer / electron transport layer / electron injection layer / cathode (xii) Anode / hole injection layer / light emitting layer / electron transport layer / electron injection layer / cathode (xiii) Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode (xiv) Anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (xv) Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (" / " indicates that each layer is stacked adjacently. The same applies below.)

[0103] The sealing layer is provided to prevent gases such as water vapor and oxygen from contacting the organic EL element. The sealing layer is formed by alternately forming inorganic films and organic films from the bottom up. The inorganic / organic laminate may be formed two or more times.

[0104] The inorganic film of the inorganic / organic laminate is a film provided to prevent the organic EL element from being exposed to gases such as water vapor and oxygen present in the environment in which the organic EL display device is placed. This inorganic film is preferably a continuous dense film with few defects such as pinholes. Examples of the inorganic film include single films such as SiN film, SiO film, SiON film, Al2O3 film, and AlN film, and laminated films thereof.

[0105] The organic film of the inorganic / organic laminate is provided to cover defects such as pinholes formed on the inorganic film and to provide flatness to the surface. The organic film is preferably formed in an area narrower than the area where the inorganic film is formed. This is because if the organic film is formed to be the same size as or wider than the area where the inorganic film is formed, the organic film will deteriorate in the exposed area. However, the top organic film formed on the top layer of the entire sealing layer is formed in approximately the same area as the area where the inorganic film is formed. The organic film is formed so that the upper surface of the sealing layer is flattened. The organic film may be a film formed using the above-mentioned photosensitive composition of the present embodiment (that is, a film including a cured product of the photosensitive composition of the present embodiment).

[0106] As described above, the photosensitive composition of the present embodiment is suitable for inkjet coating. By using the inkjet method, an organic film can be formed quickly and uniformly.

[0107] The sealing layer is preferably 1 to 5 sets, counting the inorganic / organic laminate as one set. When the inorganic / organic laminate is 6 sets or more, the sealing effect on the organic EL element is almost the same as when it is 5 sets. The thickness of the inorganic film of the inorganic / organic laminate is preferably 50 nm or more and 1 μm or less. The thickness of the organic film of the inorganic / organic laminate is preferably 1 μm or more and 15 μm or less, and more preferably 3 μm or more and 10 μm or less. When the organic film is 1 μm or more thick, particles generated during element formation can be completely covered, and the inorganic film can be applied with good flatness. When the organic film is 15 μm or less thick, moisture does not penetrate from the side of the organic film, and the reliability of the organic EL display device is further improved.

[0108] The sealing substrate is formed so as to cover the entire upper surface of the uppermost organic film of the sealing layer in close contact with it. Examples of this sealing substrate include the above-mentioned substrates. Among these, a substrate transparent to visible light is preferred. Among substrates (transparent sealing substrates) transparent to visible light, one or more selected from the group consisting of glass substrates and plastic substrates are preferred, and a glass substrate is more preferred.

[0109] The thickness of the transparent sealing substrate is preferably 1 μm to 1 mm, more preferably 10 μm to 800 μm, and most preferably 50 μm to 700 μm. By providing the transparent sealing substrate on the sealing layer, deterioration that progresses when the surface of the top organic film comes into contact with gas can be suppressed. Furthermore, the barrier properties of the organic EL display device can be further improved.

[0110] Next, a method for manufacturing an organic EL display device having the above-mentioned configuration will be described. First, an anode patterned into a predetermined shape by a known method, an organic EL layer including a light-emitting layer, and a cathode are formed in this order on a first substrate to form an organic EL element. For example, when the organic EL display device is used as a dot-matrix display device, banks are formed to separate the light-emitting region into a matrix shape, and the organic EL layer including a light-emitting layer is formed in the region surrounded by the banks.

[0111] Next, a first inorganic film having a predetermined thickness is formed on the substrate on which the organic EL element is formed by a film formation method such as a PVD (Physical Vapor Deposition) method such as a sputtering method or a CVD method such as a plasma CVD (Chemical Vapor Deposition) method. Thereafter, the photosensitive composition (sealant) of the present embodiment is attached onto the first inorganic film using a coating film forming method such as a solution coating method or a spray coating method, a flash deposition method, an inkjet method, or the like (the inkjet method is preferred in terms of productivity). Thereafter, the photosensitive composition (sealant) is cured by irradiation with energy rays such as ultraviolet rays or visible light, forming a first organic film. Through the above steps, one set of inorganic / organic laminate is formed.

[0112] The above-described process for forming an inorganic / organic laminate is repeated a predetermined number of times. However, for the last set, i.e., the topmost inorganic / organic laminate, a sealant may be applied to the top surface of the inorganic film by a coating method, a flash deposition method, an inkjet method, or the like so as to flatten the top surface.

[0113] Next, a transparent sealing substrate is bonded to the surface of the substrate to which the sealant is attached. When bonding, alignment is performed. Thereafter, energy rays are irradiated from the transparent sealing substrate side to harden the photosensitive composition (sealant) of this embodiment present between the uppermost inorganic film and the transparent sealing substrate. This hardens the photosensitive composition (sealant), forming the uppermost organic film and bonding the uppermost organic film to the transparent sealing substrate. This completes the method for manufacturing an organic EL display device.

[0114] After the photosensitive composition (sealant) is attached onto the inorganic film, the photosensitive composition (sealant) may be partially irradiated with energy rays to polymerize it. In this way, it is easy to prevent the shape of the top organic film from being distorted when a transparent sealing substrate is placed. The thicknesses of the inorganic film and the organic film may be the same for each inorganic / organic laminate, or may be different for each inorganic / organic laminate.

[0115] In this embodiment, the organic EL display device can be used as, for example, a surface light source, a segment display device, or a dot matrix display device.

[0116] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention. EXAMPLES

[0117] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. It should be noted that the present invention is not limited to the Examples.

[0118] <Production of Photosensitive Composition> (Examples 1 to 5) Using the polymerizable compounds and photopolymerization initiators shown in the table below, photosensitive compositions of Examples 1 to 5 were produced according to the following specific procedures.

[0119] (1) Pretreatment process A part of the raw polymerizable compound was pretreated by any one of the following methods. (i) Devolatilization treatment: The polymerizable compound was subjected to devolatilization treatment under conditions of 23° C. or higher, 15 minutes or longer, and 1000 Pa or lower. (ii) Distillation treatment: The polymerizable compound was distilled using a rotary distillation apparatus (Tokyo Rikakikai Co., Ltd., "Rotary Evaporator N-1000S") in a warm bath adjusted to 65°C at a pressure of 0.05 MPa and a rotation speed of 50 r / min for 3 hours. (iii) Reaction treatment: Triethylamine (6 eq.) was added to the monomer and stirred, and then methacrylic acid chloride (5 eq.) was added dropwise with stirring (solvent-free). After the dropwise addition of methacrylic acid chloride was completed, stirring was continued for another hour. Then, 100 g of pure water was added to the system, and the reaction was stopped by stirring for 10 minutes. After the reaction was stopped, the liquid was separated in the following order: 10 mass% acetic acid aqueous solution (3 times), 10 mass% sodium bicarbonate aqueous solution (3 times), and pure water (3 times). Then, the monomer (including a compound in which the hydroxy group of the hydroxy compound, which is an impurity, is capped with methacrylic acid chloride) was recovered.

[0120] (2)Mixing process The polymerizable compound and photopolymerization initiator were weighed out in the amounts (unit: parts by mass) shown in the table, and stirred at 200 rpm and 23° C. for 3 hours using a stirrer (Three-One Motor), thereby obtaining a mixture. The table below indicates whether the polymerizable compound used was treated (or not treated) by any of the methods described in (1) above.

[0121] (3) Dehydration process A dehydrating agent (molecular sieve 5A) was added in an amount of 10 mass % to the mixture obtained in (2) above, and the mixture was allowed to stand at 23° C. for 16 hours.

[0122] (4) Deoxidation process The mixture that had been subjected to the above dehydration step (3) was bubbled with dry nitrogen gas under conditions of 1000 Pa or less for 30 minutes or more.

[0123] (5) Filtration process The mixture that had been subjected to the above-mentioned deoxidation step (4) was filtered through a filter having a pore size of 1 μm or less to remove foreign matter. In this manner, a photosensitive composition was produced.

[0124] Comparative Example 1 A photosensitive composition was produced in the same manner as in Example 1, except that the pretreatment with the polymerizable compound was not carried out.

[0125] Comparative Example 2 A photosensitive composition was produced in the same manner as in Example 4, except that the pretreatment with the polymerizable compound was not carried out.

[0126] The polymerizable compounds and photopolymerization initiators used are as follows: SR262 (1,12-dodecanediol dimethacrylate): Arkema BPE200 (ethoxylated bisphenol A dimethacrylate, in the above general formula (A), R 1 , R 1 ' is a methyl group, and R 2 , R 2 ' is an ethylene group, and R 3 , R3 ' is a methyl group, and p+q=4 is the compound): Shin-Nakamura Chemical Industry Co., Ltd. A-LEN-10 (ethoxylated o-phenylphenol acrylate): Shin-Nakamura Chemical Co., Ltd. ADCP (Dimethylol-tricyclodecane dimethacrylate): Shin-Nakamura Chemical Co., Ltd. · TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide): IGM Resins

[0127] <Various measurements / evaluations> (Hydroxy compounds (including polyhydroxy compounds) concentration) 0.200 g of the photosensitive composition was weighed out in a 20 mL measuring flask, and acetone was added up to the target mark. The mixture was then shaken well to prepare a measurement sample. The measurement sample was then subjected to a gas chromatograph, and the concentration of the hydroxyl compound believed to be derived from the polymerizable compound was quantified from the peak position and peak area of ​​the obtained chart. The details of the gas chromatograph are as follows. ·Equipment: Agilent 7890B Col.: HP-5MS 60m x φ0.25mm x film thickness 0.25μm Col.Temp.: 40℃ for 1 min, then increase temperature to 180℃ at 20℃ / min, then increase temperature to 300℃ at 10℃ / min, and hold for 50 min. Inj.Temp.:300℃ Det.Temp.:300℃ Flow: 1mL / min x 22min, then 0.1mL / min, then 2mL / min, split 1 / 20 Inj: 1μL

[0128] (Dissolved oxygen concentration) The dissolved oxygen concentration in the photosensitive composition was measured at 23° C. with stirring using a dissolved oxygen meter, DO meter B-506S (diaphragm type galvanic cell type) manufactured by Iijima Electronics Co., Ltd.

[0129] (Moisture concentration (moisture content)) Aquamicron AX (manufactured by Mitsubishi Chemical Corporation) was used as the Karl Fischer solution, and the measurement was performed using a trace moisture analyzer CA-06 (manufactured by Mitsubishi Chemical Corporation).

[0130] (viscosity) The viscosity of the photosensitive composition was measured using a cone-plate type viscometer (manufactured by Eiko Seiki Co., Ltd., HB DV3T, cone plate: CPA-40Z) at 25° C. and 250 rpm.

[0131] (Reliability evaluation of organic electroluminescence display devices (organic electroluminescence reliability)) - Fabrication of OLED display elements for evaluation A 30 mm square glass substrate (700 μm thick) with an ITO electrode was washed with acetone and then isopropanol. The following compounds were then deposited in order to form thin films by vacuum deposition to obtain a substrate with a 2 mm square organic EL element consisting of an anode, hole injection layer, hole transport layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, and cathode. The composition of each layer is as follows: Anode (ITO): 150nm / polymer Hole injection layer (4,4',4"-tris{2-naphthyl(phenyl)amino}triphenylamine (2-TNATA)): 60 nm Hole transport layer (N,N'-diphenyl-N,N'-dinaphthylbenzidine (α-NPD)): 30 nm Emitting layer (Ir(ppy)3+CBP[6%]): 30nm Hole blocking layer (bis(2-methyl-8-quinolinolato)(p-phenylphenolato)aluminum (BAlq)): 10 nm Electron transport layer (tris(8-hydroxyquinolinolato)aluminum (Alq3)): 30 nm Electron injection layer (lithium fluoride (LiF)): 0.8 nm Cathode (MgAg / IZO): 10nm / 100nm

[0132] Next, the photosensitive composition was sprayed in a nitrogen atmosphere using an inkjet device (model number: DMP2850) manufactured by Fujifilm Corporation so as to cover an organic EL element of 2 mm × 2 mm, to obtain a photosensitive resin film of 10 μm in thickness. After that, in an N2 environment, an LED lamp (UV-LED LIGHT SOURCE H-4MLH200-V1 manufactured by HOYA Corporation) emitting light with a wavelength of 395 nm was used to apply an integrated light amount of 1,500 mJ / cm2 at a wavelength of 395 nm to the photosensitive resin film. 2 The coating was irradiated with light under the following conditions: As a result, a cured film was obtained. A mask (cover) with an opening of 10 mm x 10 mm was placed so as to cover the entire cured film obtained, and a SiN film was formed by plasma CVD. The thickness of the formed SiN (inorganic film) was 1 μm. In this way, an organic EL device was obtained.

[0133] The obtained organic EL element was attached to a non-alkali glass (Corning Eagle XG) of 30 mm x 30 mm x 0.7 mmt using a transparent substrate-less double-sided tape of 30 mm x 30 mm x 25 μmt. In this way, an organic EL display device for evaluation was produced.

[0134] Reliability testing The organic EL display device for evaluation obtained as described above was left to stand in a high-temperature, high-humidity environment of 85°C and 85% RH for 500 hours. Before and after this high-temperature, high-humidity treatment, a current was passed through the organic EL display device for evaluation, and the light-emitting surface was photographed. The photographed images (before and after the high-temperature, high-humidity treatment) were analyzed using Innotek's image analysis software "Quick Grain" to determine the light-emitting area. The reduction rate (%) of the light-emitting area before and after the high-temperature, high-humidity treatment was then calculated.

[0135] Information relating to the examples and comparative examples is summarized in the table below. In the table, the amounts of the polymerizable compound and the photopolymerization initiator are expressed in parts by mass.

[0136] [Table 1]

[0137] As shown in the above table, the reliability of the organic EL display devices fabricated using the photosensitive compositions of Examples 1 to 5, in which the concentration of the hydroxy compound having 2 to 40 carbon atoms was 0.01 ppm or more and 12,000 ppm or less, was better than that of the comparative example.

[0138] This application claims priority based on Japanese Patent Application No. 2020-094004, filed on May 29, 2020, the disclosure of which is incorporated herein in its entirety.

Claims

1. A photosensitive composition comprising a polymerizable compound and a photopolymerization initiator, the polymerizable compound includes a (meth)acrylate compound (excluding (meth)acrylic acid polyoxyethylenated bisphenol S ester); a (meth)acrylate compound having 2 to 40 carbon atoms, wherein a concentration of the hydroxy compound in which some or all of the (meth)acryloyloxy groups have been converted to hydroxy groups is 0.01 ppm to 12,000 ppm;

2. The photosensitive composition according to claim 1, The photosensitive composition has a polyhydroxy compound in which some or all of the (meth)acryloyloxy groups of the (meth)acrylate compound have been converted to hydroxy groups, and the concentration of the polyhydroxy compound is 0.01 ppm or more and 12,000 ppm or less.

3. The photosensitive composition according to claim 1 or 2, The photosensitive composition, wherein the polymerizable compound includes an epoxy compound.

4. A photosensitive composition according to any one of claims 1 to 3, A photosensitive composition having a dissolved oxygen concentration of 0.1 mg / L or more and 5 mg / L or less.

5. The photosensitive composition according to claim 1, wherein A photosensitive composition having a water concentration of 1 ppm or more and 50 ppm or less.

6. The photosensitive composition according to claim 1, A photosensitive composition having a viscosity of 3 mPa·s or more and 50 mPa·s or less.

7. The photosensitive composition according to claim 1, A photosensitive composition for encapsulating an organic electroluminescence element.

8. A photosensitive composition comprising a polymerizable compound and a photopolymerization initiator, the polymerizable compound includes a (meth)acrylate compound, the (meth)acrylate compound has from 2 to 40 carbon atoms, and a concentration of a hydroxy compound in which some or all of the (meth)acryloyloxy groups have been converted to hydroxy groups is from 0.01 ppm to 12,000 ppm; A photosensitive composition having a dissolved oxygen concentration of 0.1 mg / L or more and 5 mg / L or less.

9. A photosensitive composition comprising a polymerizable compound and a photopolymerization initiator, the polymerizable compound includes a (meth)acrylate compound, the (meth)acrylate compound has from 2 to 40 carbon atoms, and a concentration of a hydroxy compound in which some or all of the (meth)acryloyloxy groups have been converted to hydroxy groups is from 0.01 ppm to 12,000 ppm; A photosensitive composition having a water concentration of 1 ppm or more and 50 ppm or less.

10. A photosensitive composition comprising a polymerizable compound and a photopolymerization initiator, the polymerizable compound includes a (meth)acrylate compound, the (meth)acrylate compound has from 2 to 40 carbon atoms, and a concentration of a hydroxy compound in which some or all of the (meth)acryloyloxy groups have been converted to hydroxy groups is from 0.01 ppm to 12,000 ppm; A photosensitive composition having a viscosity of 3 mPa·s or more and 50 mPa·s or less.

11. A photosensitive composition comprising a polymerizable compound and a photopolymerization initiator, the polymerizable compound includes a (meth)acrylate compound, the (meth)acrylate compound has from 2 to 40 carbon atoms, and a concentration of a hydroxy compound in which some or all of the (meth)acryloyloxy groups have been converted to hydroxy groups is from 0.01 ppm to 12,000 ppm; A photosensitive composition for encapsulating an organic electroluminescence element.

12. A cured product of the photosensitive composition described in any one of claims 1 to 11.

13. A cured product of a photosensitive composition containing a polymerizable compound and a photopolymerization initiator, the polymerizable compound includes a (meth)acrylate compound, A cured product of a photosensitive composition, wherein the (meth)acrylate compound has 2 to 40 carbon atoms, and a concentration of a hydroxy compound in which some or all of the (meth)acryloyloxy groups have been converted to hydroxy groups is 0.01 ppm to 12,000 ppm.

14. An organic electroluminescence display device in which an organic electroluminescence element is encapsulated with the cured product described in claim 12 or 13.

15. A method for producing a photosensitive composition according to any one of claims 1 to 11, comprising: A method for producing a photosensitive composition, comprising: a pretreatment step of pretreating a raw material polymerizable compound by at least one of the following methods (i) to (iii); and a mixing step of mixing the polymerizable compound treated in the pretreatment step with a photopolymerization initiator: (i) The raw polymerizable compound is subjected to a devolatilization treatment in an environment of 10° C. to 100° C. and 1000 Pa or less for 10 minutes or more. (ii) Distilling the starting polymerizable compound. (iii) The raw polymerizable compound is treated with an acid chloride.

16. A method for producing a photosensitive composition containing a polymerizable compound and a photopolymerization initiator, comprising: the polymerizable compound includes a (meth)acrylate compound, the (meth)acrylate compound has from 2 to 40 carbon atoms, and a concentration of a hydroxy compound in which some or all of the (meth)acryloyloxy groups have been converted to hydroxy groups is from 0.01 ppm to 12,000 ppm; A method for producing a photosensitive composition, comprising: a pretreatment step of pretreating a raw material polymerizable compound by at least one of the following methods (i) to (iii); and a mixing step of mixing the polymerizable compound treated in the pretreatment step with a photopolymerization initiator: (i) The raw polymerizable compound is subjected to a devolatilization treatment in an environment of 10° C. to 100° C. and 1000 Pa or less for 10 minutes or more. (ii) Distilling the starting polymerizable compound. (iii) The raw polymerizable compound is treated with an acid chloride.