Curable composition, cured film, organic EL element, and method for producing organic EL element

Abstract

To provide a curable composition that exhibits excellent curability even while having low viscosity and can provide a cured film having a high refractive index and increased element reliability.SOLUTION: A curable composition contains [A1] a compound that contains an ethylenically unsaturated group and at least one group [F1] selected from the group consisting of a group represented by formula (1), -S(=O)-, and -S(=O)2- and has a partial structure in which the group [F1] neighbors a carbon-carbon unsaturated bond in the ethylenically unsaturated group, [A2] a compound that contains an ethylenically unsaturated group and a thioether group and has a partial structure in which the thioether group neighbors a carbon-carbon unsaturated bond in the ethylenically unsaturated group, and [B] a radical polymerization initiator. In formula (1), X1 is an oxygen atom, a sulfur atom, or a selenium atom.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition, a cured film, an organic EL device, and a method for producing an organic EL device. [Background technology]

[0002] An organic electroluminescent element (organic EL element) is a light-emitting element having a laminated structure including an anode, an organic light-emitting layer, and a cathode. Organic EL elements are widely used in various applications such as display devices and lighting devices.

[0003] The organic light-emitting layer of an organic EL element is susceptible to deterioration due to contact with moisture and oxygen. For example, there is a concern that moisture may penetrate into the element over a long period of operation, resulting in the formation of non-light-emitting areas (hereinafter also referred to as "dark spots"), or that light-emitting characteristics may be reduced due to contact with moisture and oxygen. Therefore, conventionally, a sealing structure has been provided in an organic EL element to prevent the organic light-emitting layer from coming into contact with moisture and oxygen (see, for example, Patent Documents 1 and 2). Patent Documents 1 and 2 disclose the formation of an organic sealing layer that covers the organic light-emitting layer using a curable composition containing an organic material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-26515 [Patent Document 2] International Publication No. 2021 / 010226 Summary of the Invention [Problem to be solved by the invention]

[0005] When forming a sealing structure for an organic EL element, it is desirable to be able to form a cured film without heat treatment in order to reduce damage to the element. Therefore, it is conceivable to form a sealing structure for an organic EL element by curing through radiation irradiation. In this case, the curable composition is required to have high sensitivity to radiation and to be able to obtain a highly reliable element in which the intrusion of moisture and oxygen into the element is sufficiently suppressed. Furthermore, from the viewpoint of improving the light extraction efficiency of the organic EL element, the cured film obtained from the curable composition is also required to have a high refractive index.

[0006] Furthermore, in recent years, attempts have been made to form a cured film by applying a curable composition to a substrate by inkjet coating, for reasons such as the ease of forming a uniform coating film with a small amount of curable composition and excellent throughput. In order to enable the application of the inkjet coating method to the formation of a sealing structure, the curable composition is required to have a low viscosity.

[0007] The present invention has been made in view of the above-mentioned problems, and a main object of the present invention is to provide a curable composition that has low viscosity but exhibits excellent curability, and is capable of giving a cured film that exhibits a high refractive index and can improve device reliability. [Means for solving the problem]

[0008] The present inventors have focused on forming a cured film by radical copolymerization of an electron donor monomer and an electron acceptor monomer. They have found that the above-mentioned problems can be solved by preparing a curable composition containing at least two polymerizable compounds having specific structures. That is, the present invention provides the following curable composition, cured film, organic EL device, and method for producing an organic EL device.

[0009] [1] [A1] an ethylenically unsaturated group and a compound represented by the following formula (1): [ka] (In formula (1), X 1is an oxygen atom, a sulfur atom, or a selenium atom. "*" represents a bond. and at least one group [F1] selected from the group consisting of -S(=O)- and -S(=O)2-, wherein the group [F1] has a partial structure adjacent to the carbon-carbon unsaturated bond in the ethylenically unsaturated group. [A2] A compound having an ethylenically unsaturated group and a thioether group, wherein the thioether group has a partial structure adjacent to a carbon-carbon unsaturated bond in the ethylenically unsaturated group, and [B] A curable composition comprising a radical polymerization initiator.

[0010] [2] A cured film formed from the curable composition of [1] above. [3] An organic EL device in which the light-emitting layer is sealed with the cured film of [2] above. [4] A method for producing an organic EL element, comprising the steps of applying the curable composition according to [1] above to a surface of a substrate on which an organic light-emitting layer has been formed, and curing the curable composition by irradiating with radiation, thereby forming a sealing structure. [Effects of the Invention]

[0011] The curable composition of the present invention has low viscosity and yet exhibits excellent curability. Furthermore, the curable composition of the present invention can provide a cured film that exhibits a high refractive index and can improve device reliability. DETAILED DESCRIPTION OF THE INVENTION

[0012] Matters related to the embodiments will be described in detail below. In this specification, a numerical range indicated using "to" means that the numerical values ​​before and after "to" are included as the lower and upper limits.

[0013] 《Curable composition》 The curable composition of the present disclosure (hereinafter also referred to as "the composition") contains an [A1] compound, an [A2] compound, and a [B] radical polymerization initiator. Radiation irradiation of the composition causes radical copolymerization of the [A1] compound and the [A2] compound to proceed, resulting in a cured film. The composition is useful as an encapsulant for thin film encapsulation (TFE) of organic electroluminescence devices (organic EL devices). Each component contained in the composition and other components that may be blended as necessary are described below. Unless otherwise specified, each component may be used alone or in combination of two or more.

[0014] Here, in this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed only of a chain structure. However, it may be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, it does not necessarily have to be composed only of an alicyclic hydrocarbon structure, and it also includes those that have a chain structure as part of it. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, it does not necessarily have to be composed only of an aromatic ring structure, and it may contain a chain structure or an alicyclic hydrocarbon structure as part of it. The ring structures of alicyclic hydrocarbon groups and aromatic hydrocarbon groups may have a substituent composed of a hydrocarbon structure. "Cyclic hydrocarbon group" refers to a hydrocarbon group that includes alicyclic hydrocarbon groups and aromatic hydrocarbon groups. The term "structural unit" refers to a unit that mainly constitutes the main chain structure, and at least two or more units are contained in the main chain structure.

[0015] <[A1] Compound> The compound [A1] is a photopolymerizable compound having an ethylenically unsaturated group and at least one group [F1] selected from the group consisting of a group represented by the following formula (1), -S(=O)-, and -S(=O)2-. [ka] (In formula (1), X 1 is an oxygen atom, a sulfur atom, or a selenium atom. "*" represents a bond.

[0016] The ethylenically unsaturated group contained in the compound [A1] is, for example, a group having -CH=CR- (where R is a hydrogen atom or a monovalent hydrocarbon group). In the compound [A1], a group [F1] is bonded to at least one of the two carbon atoms constituting the carbon-carbon unsaturated bond.

[0017] The number of ethylenically unsaturated groups contained in one molecule of the compound [A1] is not particularly limited. From the viewpoint of increasing the sensitivity of the composition and suppressing outgassing from the cured film, the number of ethylenically unsaturated groups contained in the compound [A1] is preferably 2 or more. Furthermore, from the viewpoint of obtaining a curable composition with a sufficiently low viscosity, the number of ethylenically unsaturated groups contained in the compound [A1] is preferably 10 or less, more preferably 6 or less, and even more preferably 4 or less.

[0018] Regarding the group [F1], X in formula (1) 1 is preferably an oxygen atom or a sulfur atom from the viewpoint of availability. The number of groups [F1] contained in one molecule of the compound [A1] is not particularly limited, and may be one or more. The number of groups [F1] contained in one molecule of the compound [A1] is, for example, 10 or less from the viewpoint of suppressing outgassing in the cured film. From the viewpoint of curability, the group [F1] is preferably a group represented by formula (1) or -S(=O)-, and from the viewpoint of obtaining a cured film with a high refractive index, a group represented by formula (1) is more preferred.

[0019] The compound [A1] has a partial structure in which the group [F1] is adjacent to a carbon atom constituting a carbon-carbon unsaturated bond in an ethylenically unsaturated group. Specifically, the compound [A1] preferably has at least one selected from the group consisting of a partial structure represented by the following formula (2-1) and a partial structure represented by the following formula (2-2): [ka] (In formula (2-1) and formula (2-2), R 1 is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms. 1 is an oxygen atom, a sulfur atom, or a selenium atom. 1 is -S(=O)- or -S(=O)2-. "*" represents a bond.)

[0020] In formula (2-1) and formula (2-2), R 1 Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 1 The alkyl group having 1 to 6 carbon atoms represented by the formula (R) may be linear or branched. 1 Specific examples of the alkyl group having 1 to 6 carbon atoms represented by R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. 1 Among these, a hydrogen atom, a halogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0021] As the compound [A1], at least one selected from the group consisting of compounds represented by the following formula (3-1) and compounds represented by the following formula (3-2) can be preferably used. [ka] (In formula (3-1), R 2 is a monovalent organic group having 1 to 20 carbon atoms. r is an integer of 1 to 3. When r is 2 or 3, multiple R 1 are the same or different, and when r is 1, multiple R 2 are the same or different. R 1 and X 1 is synonymous with formula (2-1). In formula (3-2), R 3 is a t-valent organic group having 1 to 20 carbon atoms, where t is an integer of 1 to 4. When t is 2 or more, multiple R 1 are the same or different, and multiple Y 1 are the same or different. R 1 and Y1 is equivalent to formula (2-2).

[0022] In formula (3-1), R 2 The monovalent organic group having 1 to 20 carbon atoms represented by the formula "-OR" includes a monovalent hydrocarbon group having 1 to 20 carbon atoms, 4 " and a group represented by the formula "-SR 4 " (wherein R 4 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms. 2 and R 4 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a linear or branched alkyl group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0023] Specific examples of alkyl groups having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-decyl, etc. Among these, linear or branched alkyl groups having 1 to 10 carbon atoms are preferred, and linear or branched alkyl groups having 1 to 5 carbon atoms are more preferred.

[0024] Specific examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

[0025] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include an aryl group having 6 to 20 carbon atoms and an aralkyl group having 7 to 20 carbon atoms. Specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a methylphenyl group, an ethylphenyl group, a dimethylphenyl group, a diethylphenyl group, a trimethylphenyl group, a naphthyl group, and an anthryl group. Specific examples of the aralkyl group having 7 to 20 carbon atoms include a benzyl group, a phenethyl group, a naphthylmethyl group, and an anthrylmethyl group.

[0026] R 2 and R 4 Of these, the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) is preferably an alkyl group having 1 to 10 carbon atoms and a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a naphthyl group.

[0027] In formula (3-2), R 3 Examples of the t-valent organic group having 1 to 20 carbon atoms and represented by the formula (I) include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group having 1 to 20 carbon atoms and having 1 to 20 carbon atoms. Specific examples of these include R 2 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms and represented by the formula (I) include groups in which (t-1) hydrogen atoms have been removed from the groups exemplified above. 3 is a t-valent chain hydrocarbon group having 1 to 20 carbon atoms, R 3 The chain hydrocarbon group represented by R may be saturated or unsaturated. 3 Specific examples of unsaturated chain hydrocarbon groups represented by the formula (I) include groups in which t hydrogen atoms have been removed from an alkene having 2 to 20 carbon atoms.

[0028] In formula (3-1), r is an integer of 1 to 3, preferably 2 or 3. In formula (3-2), t is an integer of 1 to 4, preferably 1 to 3, more preferably 1 or 2.

[0029] In addition, R in formula (3-2) 3 When R has an ethylenically unsaturated group, the number of ethylenically unsaturated groups in one molecule of the compound [A1] is 3Similarly, the number of ethylenically unsaturated groups in R in formula (3-1) is the sum of t and the number of ethylenically unsaturated groups in R 2 When R has an ethylenically unsaturated group, the number of ethylenically unsaturated groups in one molecule of the compound [A1] is 2 The number is the sum of the number of ethylenically unsaturated groups and r. 2 It is preferred that the alkyl group does not have an ethylenically unsaturated group.

[0030] Specific examples of the compound [A1] include compounds represented by formula (3-1), such as dimethyl vinyl phosphonate, diethyl vinyl phosphonate, ethyl methyl vinyl phosphonate, methyl phenyl vinyl phosphonate, diphenyl vinyl phosphonate, methyl divinyl phosphine oxide, ethyl divinyl phosphine oxide, phenyl divinyl phosphine oxide, phenyl divinyl phosphine sulfide, trivinyl phosphine oxide, trivinyl phosphine sulfide, diphenyl vinyl phosphine sulfide, trivinyl phosphine selenide, diphenyl vinyl phosphine selenide, phenyl divinyl phosphine selenide, and methyl divinyl phosphine selenide.

[0031] Examples of the compound represented by formula (3-2) include bis(vinylsulfonyl)methane, bis(vinylsulfonyl)ethane, bis(vinylsulfonyl)propane, divinyl sulfone, vinylphenyl sulfoxide, divinyl sulfoxide, and phenyl vinyl sulfone.

[0032] Of the above, the compound [A1] is preferably a compound represented by formula (3-1) from the viewpoints of the curability of the composition and the refractive index of the resulting cured film.

[0033] In the present composition, the content of the compound [A1] is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, based on 100 parts by mass of the total amount of polymerizable compounds contained in the composition. Furthermore, the content of the compound [A1] is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, based on 100 parts by mass of the total amount of polymerizable compounds contained in the composition. A content of the compound [A1] within the above range is advantageous in that it enables the production of a curable composition that exhibits an excellent balance between low viscosity and curability, and in that when the present composition is used to form a cured film that constitutes an organic EL device, the organic EL device can have high reliability.

[0034] The term "polymerizable compound" refers to a compound capable of generating a polymer in response to a stimulus. In this specification, the terms "polymerizable compound" refer to the compounds [A1] and [A2] contained in the composition, as well as any compound optionally blended in the composition that is capable of copolymerizing with the compounds [A1] and [A2] (i.e., the compound [A3] described below).

[0035] <[A2] Compound> The compound [A2] is a photopolymerizable sulfide compound having an ethylenically unsaturated group and a thioether group (-S-), in which the thioether group has a partial structure (hereinafter also referred to as a "specific sulfide structure") adjacent to a carbon-carbon unsaturated bond in the ethylenically unsaturated group.

[0036] The ethylenically unsaturated group contained in the specific sulfide structure includes a group having -CH=CR- (where R is a hydrogen atom or a monovalent hydrocarbon group). In the specific sulfide structure, a sulfur atom is bonded to at least one of the two carbon atoms constituting the carbon-carbon unsaturated bond. The ethylenically unsaturated group contained in the compound [A2] is a group having R 11 -CH=CH-(where R 11 is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms).

[0037] From the viewpoints of increasing the sensitivity of the composition and suppressing outgassing from the cured film, the number of ethylenically unsaturated groups contained in one molecule of the compound [A2] is preferably 2 or more. Furthermore, from the viewpoint of obtaining a curable composition with a sufficiently low viscosity, the number of ethylenically unsaturated groups contained in the compound [A2] is preferably 10 or less, more preferably 6 or less, and even more preferably 4 or less.

[0038] The compound [A2] is not particularly limited as long as it has one or more specific sulfide structures in one molecule. From the viewpoint of increasing the refractive index of a cured film formed using the present composition, it is preferable that the compound [A2] has an aromatic ring and a partial structure in which a sulfur atom adjacent to a carbon atom constituting an ethylenically unsaturated bond (i.e., a sulfur atom in the specific sulfide structure) is bonded to the aromatic ring.

[0039] When the compound [A2] has an aromatic ring, examples of the aromatic ring include an aromatic hydrocarbon ring and an aromatic heterocycle. Specific examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. Examples of the aromatic heterocycle include a nitrogen-containing aromatic heterocycle such as a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a 1,3,5-triazine ring, and an imidazole ring; an oxygen-containing aromatic heterocycle such as a furan ring and an oxazole ring; and a sulfur-containing aromatic heterocycle such as a thiophene ring, a thiazole ring, and a 1,3,4-thiadiazole ring. Of these, the aromatic ring contained in the compound [A2] is particularly preferably a benzene ring, a naphthalene ring, a 1,3,5-triazine ring, or a 1,3,4-thiadiazole ring.

[0040] Specifically, the compound [A2] is preferably a compound represented by the following formula (5). [ka] (In formula (5), R 11 is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms. 1 is a u-valent group having an aromatic ring, provided that R 11The sulfur atom that makes up -CH=CH-S- is Ar 1 The aromatic ring is bonded to the ring. u is an integer of 1 to 10. When u is 2 or more, multiple R 11 are the same or different.)

[0041] In equation (5), R 11 Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 11 The alkyl group having 1 to 6 carbon atoms represented by the formula (R) may be linear or branched. 11 Specific examples of the alkyl group having 1 to 6 carbon atoms represented by R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. 11 From the viewpoint of further enhancing the curability of the present composition, among these, a hydrogen atom, a halogen atom, or a methyl group is preferred, and a hydrogen atom is more preferred.

[0042] Ar 1 Examples of the aromatic ring contained in the compound [A2] include the aromatic rings exemplified above in the description of the aromatic ring that the compound [A2] may contain. 1 is preferably a group in which u hydrogen atoms have been removed from the ring portion of a structure represented by any one of the following formulas (6-1) to (6-5). [ka] (In formulas (6-1) to (6-3), R 12 and R 13 are each independently a halogen atom or an alkyl group having 1 to 6 carbon atoms. a1 and a2 are each independently an integer of 0 to 4. a3 is an integer of 0 to 5. a4 is an integer of 0 to 7. R 12 If there are multiple R 12 are the same or different, R 13 If there are multiple R 13 are the same or different.)

[0043] In formulas (6-1) to (6-3), R 12 and R13 For halogen atoms and alkyl groups having 1 to 6 carbon atoms represented by R 11 The same explanations as for halogen atoms and alkyl groups having 1 to 6 carbon atoms represented by R 12 and R 13 is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. a1 and a2 are preferably 0 to 2.

[0044] As the compound [A2], at least one selected from the group consisting of a compound represented by the following formula (7-1), a compound represented by the following formula (7-2), a compound represented by the following formula (7-3), a compound represented by the following formula (7-4), and a compound represented by the following formula (7-5) can be preferably used. [ka] (In formulas (7-1) to (7-5), R 14 , R 15 and R 16 are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms. a5 is an integer of 0 to 5. a6 is an integer of 0 to 7, provided that a3+a5≦5 and a4+a6≦7 are satisfied. R 15 If there are multiple R 15 are the same or different. R 12 , R 13 , a1, a2, a3, and a4 have the same meanings as in formulas (6-1) to (6-3), respectively.)

[0045] Examples of the compound [A2] include bis(4-vinylthiophenyl) sulfide, bis(3-methyl-4-vinylthiophenyl) sulfide, bis(3,5-dimethyl-4-vinylthiophenyl) sulfide, 1,3-bis(vinylmercapto)benzene, 1,5-bis(vinylmercapto)naphthalene, 2,6-bis(vinylmercapto)naphthalene, 2,5-divinylmercapto-1,3,4-thiadiazole, and 2,4,6-trivinylmercapto-1,3,5-triazine.

[0046] In the present composition, the content of the compound [A2] is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the total amount of polymerizable compounds contained in the composition. Also, the content of the compound [A2] is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less, per 100 parts by mass of the total amount of polymerizable compounds contained in the composition.

[0047] The ratio of the [A1] compound to the [A2] compound in the present composition is preferably determined based on the total number of ethylenically unsaturated groups (NA) possessed by the [A1] compound and the total number of ethylenically unsaturated groups (NB) possessed by the [A2] compound. Specifically, the amounts of the [A1] compound and the [A2] compound in the present composition are preferably determined so that the molar ratio of NA to NB is (NA):(NB) = 1:0.5 to 1:1.5. Blending the [A1] compound and the [A2] compound so that the ratio of NA to NB falls within the above range is advantageous in that it increases the sensitivity of the present composition, yields a composition with excellent curability, and suppresses outgassing of the cured film. From these perspectives, the (NA):(NB) ratio is more preferably 1:0.7 to 1:1.3, and even more preferably 1:0.8 to 1:1.2.

[0048] <[B] Radical polymerization initiator> The radical polymerization initiator is preferably a photoradical polymerization initiator that generates radicals in response to radiation and initiates polymerization. The radical polymerization initiator to be used is not particularly limited, but examples thereof include O-acyloxime compounds, acetophenone compounds, biimidazole compounds, and acylphosphine oxide compounds.

[0049] Examples of the O-acyloxime compound include 1,2-octanedione 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime), 1-(9-ethyl-6-benzoyl-9.H.-carbazol-3-yl)-octan-1-one oxime-O-acetate, 1-[9-ethyl-6-(2-methylbenzoyl)-9.H.-carbazol-3-yl]-ethan-1-one oxime-O-benzoate, 1-[9-n-butyl-6-(2-ethylbenzoyl)-9.H.-carbazol-3-yl]-ethan-1-one oxime-O-benzoate, ethanone-1- [9-ethyl-6-(2-methyl-4-tetrahydrofuranylbenzoyl)-9.H.-carbazol-3-yl]-1-(O-acetyloxime), ethanone-1-[9-ethyl-6-(2-methyl-4-tetrahydropyranylbenzoyl)-9.H.-carbazol-3-yl]-1-(O-acetyloxime), ethanone-1-[9-ethyl-6-(2-methyl-5-tetrahydrofuranylbenzoyl)-9.H.-carbazol-3-yl]-1-(O-acetyloxime), ethanone-1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxolanyl)methoxybenzoyl}-9.H.-carbazol-3-yl]-1-(O-acetyloxime), and the like. Of the O-acyloxime compounds, polymerization initiators having a carbazole skeleton in the molecule (for example, ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) and the like) can be preferably used.

[0050] Examples of acetophenone compounds include α-aminoketone compounds and α-hydroxyketone compounds. Specific examples of these include α-aminoketone compounds such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, and 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one. Examples of α-hydroxyketone compounds include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexylphenyl ketone.

[0051] Examples of biimidazole compounds include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, and 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole.

[0052] Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0053] The content of the radical polymerization initiator in the composition is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, per 100 parts by mass of the total amount of polymerizable compounds contained in the composition. The content of the radical polymerization initiator is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the total amount of polymerizable compounds contained in the composition. By keeping the content of the radical polymerization initiator within the above range, good curability and the like can be exhibited.

[0054] <Other ingredients> In addition to the above-described compound [A1], compound [A2], and radical polymerization initiator [B], the present composition may further contain components other than compound [A1], compound [A2], and radical polymerization initiator [B] (hereinafter also referred to as "other components"). Examples of other components include compound [A3], polymerization inhibitor [C], and surfactant [D].

[0055] ·[A3] Compound The compound [A3] is a component copolymerizable with the compounds [A1] and [A2] and can form a polymer together with the compounds [A1] and [A2] upon irradiation. The compound [A3] can be incorporated into the composition for the purposes of adjusting the viscosity of the composition or reinforcing the crosslinked structure. Compounds having an ethylenically unsaturated group are preferred as the compound [A3]. Specific examples include vinyl group-containing compounds, (meth)acryloyl group-containing compounds, and aromatic vinyl compounds. Among these, (meth)acryloyl group-containing compounds are preferred because of their copolymerizability with the compounds [A1] and [A2] and their relatively easy viscosity adjustment.

[0056] The compound [A3] may be either a monofunctional compound or a polyfunctional compound. Specific examples of the compound [A3] that is a monofunctional compound include (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having an alicyclic structure, (meth)acrylic acid esters having an aromatic ring structure, and aromatic vinyl compounds.

[0057] Specific examples of the above compounds include alkyl (meth)acrylate esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate. Specific examples of the (meth)acrylate esters having an alicyclic structure include cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, tricyclo[5.2.1.0](meth)acrylate, and the like. 2,6 ] decan-8-yl, (meth)acrylic acid tricyclo[5.2.1.0 2,5 ]decan-8-yloxyethyl, isoboronyl (meth)acrylate, etc. Examples of (meth)acrylic acid esters having an aromatic ring structure include phenyl (meth)acrylate, benzyl (meth)acrylate, naphthylmethyl (meth)acrylate, naphthylethyl (meth)acrylate, phenoxyethyl (meth)acrylate, m-phenoxyphenylmethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, etc. Examples of aromatic vinyl compounds include styrene, methylstyrene, α-methylstyrene, t-butoxystyrene, vinylnaphthalene, etc.

[0058] When the compound [A3] is a polyfunctional compound, a polyfunctional (meth)acrylic acid ester can be preferably used. Examples of polyfunctional (meth)acrylic acid esters include bifunctional (meth)acrylic acid esters and trifunctional or higher functional (meth)acrylic acid esters. Specific examples of these include bifunctional (meth)acrylic acid esters such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate.

[0059] Examples of trifunctional or higher functional (meth)acrylic acid esters include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, tri(2-(meth)acryloyloxyethyl)phosphate, amber, Examples include acid-modified pentaerythritol tri(meth)acrylate, succinic acid-modified dipentaerythritol penta(meth)acrylate, and carboxy group-containing polybasic acid-modified (meth)acrylic oligomers, as well as polyfunctional urethane acrylate compounds obtained by reacting a compound having a linear alkylene group and an alicyclic structure and having two or more isocyanate groups with a compound having one or more hydroxy groups in the molecule and three, four, or five (meth)acryloyloxy groups.

[0060] From the viewpoint of ensuring the curability of the composition, the content of the compound [A3] is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the total amount of polymerizable compounds contained in the composition (i.e., compound [A1], compound [A2], and compound [A3]). Furthermore, when compound [A3] is incorporated into the composition, the content of compound [A3] is preferably 1 part by mass or more, more preferably 5 parts by mass or more, per 100 parts by mass of the total amount of polymerizable compounds contained in the composition, from the viewpoint of fully obtaining the effect of improving viscosity and the like due to the incorporation of compound [A3].

[0061] [C] Polymerization inhibitor The polymerization inhibitor is a component that enhances the storage stability of the composition. The polymerization inhibitor is not particularly limited, but examples thereof include sulfur, quinones (e.g., benzoquinone), hydroquinones (e.g., hydroquinone, 2,5-di-t-butylhydroquinone), polyoxy compounds (e.g., p-methoxyphenol), amine compounds (e.g., N,N-diethylhydroxyamine), and nitrosamine compounds (e.g., N-nitroso-N-phenylhydroxylamine aluminum).

[0062] When a polymerization inhibitor is blended in the present composition, the content of the polymerization inhibitor is preferably 0.01 to 1.5 parts by mass, more preferably 0.02 to 1.2 parts by mass, and even more preferably 0.02 to 1.0 part by mass, per 100 parts by mass of the total amount of polymerizable compounds contained in the present composition.

[0063] [D] Surfactants A surfactant can be used to improve the coating properties of the composition (i.e., to improve wetting and spreading properties and reduce coating unevenness). Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.

[0064] Specific examples of surfactants include fluorine-based surfactants, such as Megafac F-171, F-172, F-173, F-251, F-430, F-554, and F-563 (manufactured by DIC Corporation); Fluorad FC430 and FC431 (manufactured by Sumitomo 3M Limited); Asahiguard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106, and S-611 (manufactured by AGC Seimi Chemical Co., Ltd.); Polyflow No. 75 and No. 95 (manufactured by Kyoeisha Chemical Co., Ltd.); FTX-218 (manufactured by Neos Corporation); and F-top EF301, EF303, and EF352 (manufactured by Shin-Akita Chemical Co., Ltd.).

[0065] The silicone surfactants include the following trade names: SH200-100cs, SH28PA, SH30PA, SH89PA, SH190, SH8400, SH193, SZ6032, SF8428, DC57, DC190, PAINTAD19, FZ-2101, FZ-77, FZ-2118, L-7001, and L-7002 (Toray Dow Corning). Gusha Organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.); BYK-300, 306, 310, 330, 335, 341, 344, 370, 340, and 345 (manufactured by BYK Japan).

[0066] Examples of nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate.

[0067] When a surfactant is blended in the present composition, the content of the surfactant is preferably 0.01 to 3 parts by mass, more preferably 0.02 to 2 parts by mass, and even more preferably 0.1 to 1.0 part by mass, per 100 parts by mass of the total amount of polymerizable compounds contained in the present composition.

[0068] In addition to the above, other components include, for example, antioxidants, sensitizers, softeners, plasticizers, adhesion aids, organic solvents, etc. The blending ratio of these components is appropriately selected depending on each component within a range that does not impair the effects of the present disclosure.

[0069] Here, if necessary for purposes such as dissolving the components blended in the composition, an organic solvent may be blended in the composition. However, from the viewpoint of enabling the formation of a cured film (particularly an organic sealing layer that protects the organic light-emitting layer of an organic EL device) without heat treatment, it is preferable to use as little organic solvent as possible. Specifically, the content of organic solvent in the composition is preferably 0% by mass or more and 3% by mass or less, more preferably 0% by mass or more and 2% by mass or less, and particularly preferably substantially free. Herein, "substantially free of organic solvent" means that the amount of organic solvent contained in the composition is 1% by mass or less, preferably 0.5% by mass or less.

[0070] When an organic solvent is blended into the present composition, the organic solvent used is preferably an organic solvent that can dissolve or disperse each component blended in the present composition but does not react with each component, such as alcohols, ketones, esters, ethers, aromatic hydrocarbons, and amides.

[0071] Specific examples of these include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol. Ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Esters include ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and methyl-3-methoxypropionate. Ethers include polyoxyethylene lauryl ether, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and diethylene glycol methyl ethyl ether. Aromatic hydrocarbons include benzene, toluene, and xylene. Amides include dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0072] The composition can be prepared by mixing the compound [A1], the compound [A2], the radical polymerization initiator [B], and other components that are blended as needed. From the viewpoint of obtaining a curable composition with good sensitivity and forming a cured film with high sealing effect, the content of the polymerizable compound in the composition is preferably 80 parts by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, relative to 100 parts by mass of the total amount of the composition.

[0073] The viscosity of the composition, measured using an E-type viscometer at 25°C and 20 rpm, is preferably in the range of 1.0 to 40.0 mPa·s. When the viscosity of the composition is 40.0 mPa·s or less, the composition exhibits good wetting and spreading properties when applied to a substrate by inkjet coating, thereby preventing uneven application due to cissing and other problems. Furthermore, when the viscosity of the composition is 1.0 mPa·s or more, the composition can be applied to a substrate with a sufficient film thickness, forming an organic sealing layer that exhibits sufficient sealing effect. Therefore, such a composition is particularly suitable as a curable composition for inkjet coating.

[0074] From the viewpoint of obtaining a curable composition with excellent inkjet coatability, the viscosity of the composition is more preferably 35.0 mPa·s or less, even more preferably 30.0 mPa·s or less, and particularly preferably 25.0 mPa·s or less. Furthermore, from the viewpoint of ensuring a sufficient film thickness, the viscosity of the composition is more preferably 2.0 mPa·s or more, even more preferably 5.0 mPa·s or more. In this specification, the viscosity of the curable composition is a value measured in accordance with JIS K2283.

[0075] Although not intended to limit the scope of the present invention, it is believed that in the radical copolymerization of the [A1] compound and the [A2] compound, the [A1] compound, which has a relatively low electron density in its ethylenically unsaturated bond, acts as an electron-accepting monomer, and the [A2] compound, which has a relatively high electron density in its ethylenically unsaturated bond, acts as an electron-donating monomer, resulting in alternating copolymerization of the [A1] compound and the [A2] compound. This may result in a more rapid curing reaction compared to the radical polymerization of the [A1] compound alone or the [A2] compound alone. As a result, the curable composition of the present disclosure containing the [A1] compound and the [A2] compound exhibits high sensitivity and excellent curability while achieving low viscosity. Furthermore, this composition is advantageous in that it allows for a reduced amount of the [A2] compound to be used, thereby enabling low odor.

[0076] <Cured film and organic EL element> The cured film of the present disclosure (hereinafter also referred to as the "cured film") is formed from the curable composition prepared as described above. This composition can provide a cured film exhibiting a high refractive index of 1.55 or more, and even 1.60 or more. This composition can be used as various materials, such as sealing structures for organic EL devices, microlenses, antireflection films, and optical gratings for AR devices. In particular, the composition is particularly useful as a sealant for performing thin film encapsulation (TFE) on organic EL devices, i.e., as a sealant for organic EL devices.

[0077] The present cured film and an organic EL device in which the organic light-emitting layer is sealed with the present cured film can be produced using the present composition by a method including the following steps 1 and 2. (Step 1) A step of applying the present composition to the surface of a substrate on which an organic light-emitting layer is formed. (Step 2) A step of curing the composition by irradiating with radiation Each step will be described in detail below.

[0078] [Process 1: Coating process] In this process, the present composition is applied to the light-emitting layer-forming surface of a substrate on which an organic light-emitting layer has been formed, thereby forming a coating film made of the present composition on the light-emitting layer-forming surface. The substrate to which the present composition is applied has a laminate formed thereon, including various layers such as an anode layer, a hole injection layer, a hole transport layer, an electron injection layer, and a cathode layer in addition to the organic light-emitting layer, and this laminate constitutes an organic EL device. The light-emitting layer-forming surface to which the present composition is applied may be covered with an inorganic film (inorganic sealing layer). Examples of inorganic materials that constitute the inorganic film include silicon nitride (SiNx) and silicon oxide (SiOx). In this case, a thin-film sealing layer comprising an organic sealing layer and an inorganic sealing layer is formed on the organic light-emitting layer as a sealing structure.

[0079] Examples of methods for applying the present composition include spraying, roll coating, spin coating, slit die coating, bar coating, and inkjet coating. Among these, inkjet coating is preferred from the viewpoints of throughput and thinning. In particular, the present composition is suitable for inkjet coating because it exhibits excellent curability despite its low viscosity.

[0080] [Process 2: Curing process] In this step, the coating film formed in step 1 above is irradiated with radiation to cure the coating film and form a cured film. Examples of radiation include charged particle beams such as ultraviolet light, far ultraviolet light, visible light, X-rays, and electron beams. Among these, ultraviolet light is preferred, and for example, ultraviolet light with a wavelength of 350 to 400 nm can be preferably used as the irradiation light. The radiation exposure dose is 0.05 to 10 J / m 2 This makes it possible to obtain an organic EL device coated with an organic sealing layer made of the present composition. The thickness of the cured film is usually 0.5 to 15 μm. The organic sealing layer formed from the present composition may be further coated with an inorganic film. Examples of inorganic materials that constitute the inorganic film include silicon nitride (SiNx) and silicon oxide (SiOx). [Example]

[0081] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0082] 1. Compound synthesis [Synthesis Example 1] Synthesis of Compound (A1-1) A 3 L three-neck flask equipped with a nitrogen inlet tube and a thermometer was charged with 1 L of dehydrated diethyl ether, 1 L of dehydrated tetrahydrofuran, 38 mL of phenylphosphonic acid dichloride, and 20 mg of 4-methoxyphenol, and cooled to -70 °C with dry ice acetone. Next, 536 mL of 1.0 M vinylmagnesium solution was added dropwise so that the internal temperature did not exceed -70 °C, and then the mixture was stirred at -70 °C for 3 hours. After completion of the reaction, the reaction solution was separated and washed with 2 L of 2.4 M aqueous hydrochloric acid. The aqueous layer was removed, and the organic layer was washed three times with saturated aqueous sodium bicarbonate. The mixture was then dried over anhydrous sodium sulfate, purified using a silica column (developed with ethyl acetate), concentrated under reduced pressure, and dried in vacuo to obtain 23 g of a white solid, compound (A1-1) (see Scheme 1). [ka]

[0083] [Synthesis Example 2] Synthesis of Compound (A1-3) Synthesis was carried out in the same manner as in Synthesis Example 1, except that 27.5 g of phosphoryl chloride was used instead of 38 mL of phosphonic dichloride, to obtain 17 g of a white solid of compound (A1-3) (see Scheme 2). [ka]

[0084] [Synthesis Example 3] Synthesis of Compound (A2-2) A 1000 mL three-neck flask equipped with a nitrogen inlet tube and a thermometer was charged with 12.8 g of bismuthiol, 320 g of 1,2-dibromoethane, and 0.7 g of tetrabutylammonium bromide and cooled on ice. Next, 34.9 g of 30% aqueous potassium hydroxide solution was added so that the temperature did not exceed 30°C, and the reaction was allowed to proceed for 3 hours at or below 30°C. After the reaction was completed, the aqueous layer was discarded, and the organic layer was washed twice with water, dried over magnesium sulfate, and concentrated under reduced pressure to dryness, yielding a white solid of compound (A2-2-1). Next, all of the compound (A2-2-1) obtained above was added to a 500 mL three-neck flask equipped with a nitrogen inlet tube and a thermometer, followed by the addition of 170 g of dimethyl sulfoxide and cooling on ice. Next, 27 g of 50% aqueous potassium hydroxide solution was added so that the internal temperature did not exceed 30°C, and the reaction was allowed to proceed at room temperature for 3 hours. After the reaction was completed, 500 mL of ethyl acetate was added and the aqueous layer was removed. The organic layer was washed twice with water, concentrated under reduced pressure, and dried in vacuo to obtain 7.5 g of a liquid compound (A2-2) (see Scheme 3). [ka]

[0085] 2. Preparation of Curable Composition The types and abbreviations of the [A1] compound, [A2] compound, [A3] compound, [B] radical polymerization initiator, [C] polymerization inhibitor, and [D] surfactant used in preparing the curable composition are shown below. <[A1] Compound> (A1-1): Phenyldivinylphosphine oxide (compound obtained in Synthesis Example 1) (A1-2): Diethyl vinylphosphonate (Tokyo Chemical Industry Co., Ltd.) (A1-3): Trivinylphosphine oxide (compound obtained in Synthesis Example 2) (A1-4): Bis(vinylsulfonyl)methane (Tokyo Chemical Industry Co., Ltd.) (A1-5): Vinyl phenyl sulfoxide (Tokyo Chemical Industry Co., Ltd.) <[A2] Compound> (A2-1): Bis(4-vinylthiophenyl) sulfide (Sumitomo Seika Chemicals) (A2-2): 2,5-divinylmercapto-1,3,4-thiadiazole (compound obtained in Synthesis Example 3) <[A3] Compound> (A3-1): Acrylic monomer, product name "Light Acrylate POB-A" (manufactured by Kyoeisha Chemical Co., Ltd.) (A3-2): Neopentyl glycol diacrylate, trade name "A-NPG" (manufactured by Shin-Nakamura Chemical Co., Ltd.) (A3-3): Acrylic monomer, product name "Light Acrylate NMT-A" (manufactured by Kyoeisha Chemical Co., Ltd.) <[B] Radical polymerization initiator> (B-1): Photoradical polymerization initiator, product name "TR-PBG-345" (manufactured by TRONLY) (B-2): Photoradical polymerization initiator, product name "Omnirad TPO" <[C] Polymerization inhibitor> (C-1): N-nitroso-N-phenylhydroxylamine aluminum (C-2): 2,5-di-t-butylhydroquinone <[D] Surfactant> (D-1): Silicone surfactant, trade name "DOWSIL™ SH8400" (manufactured by Dow Corning Toray Co., Ltd.) (D-2): Silicone surfactant, trade name "PAINTAD19" (manufactured by Dow Corning Toray Co., Ltd.)

[0086] [Example 1] 30 parts by mass of compound (A1-1), 70 parts by mass of compound (A2-1), 3 parts by mass of radical polymerization initiator (B-1), 0.5 parts by mass of polymerization inhibitor (C-1), and 0.5 parts by mass of surfactant (D-1) were added, mixed and stirred, and then filtered using a 0.2 μm filter to prepare curable composition (T-1).

[0087] [Examples 2 to 10, Comparative Examples 1 to 4] Curable compositions of Examples 2 to 10 and Comparative Examples 1 to 4 were prepared in the same manner as in Example 1, except that the types and amounts (parts by mass) of each component shown in Table 1 were used.

[0088]

Table 1

[0089] 3. Evaluation For the curable compositions of Examples 1 to 10 and Comparative Examples 1 to 4, the viscosity was measured and the coating unevenness by inkjet coating (IJ coating) was evaluated. Further, a cured film was formed using the curable compositions of Examples 1 to 10 and Comparative Examples 1 to 4, and the following items were evaluated by the method described below. The evaluation results are shown in Table 2. In Table 2, "-" indicates that the evaluation was not performed.

[0090] <Measurement of Viscosity> Using an E-type viscometer (RE-85L manufactured by Toki Sangyo Co., Ltd.), the viscosity (mPa·s) of the curable composition at 25°C and 20 rpm was measured.

[0091] <Evaluation of IJ Coating Unevenness> SiNx was formed on a glass substrate with a film thickness of 100 nm to prepare a substrate for evaluation. With respect to this evaluation substrate, inkjet ejection of the curable composition was performed from an inkjet head of a piezo-type inkjet printer at a pitch of 50 μm × 50 μm to prepare a coating film of 10 cm square. Further, after 5 minutes, ultraviolet irradiation was performed using a 395 nm LED lamp with an exposure amount of 3000 mJ / cm 2 to cure the coating film. At that time, the voltage conditions of the inkjet head were changed so that the film thickness of the cured film became 8 μm, and the amount of one drop of the ejected ink dot was adjusted. The obtained cured film was observed visually and with a microscope (100 times magnification), and the evaluation of IJ coating unevenness was performed according to the following criteria. ◎: No coating unevenness is observed visually and with a microscope. ○: Coating unevenness is observed with a microscope, but not visually. △: Coating unevenness due to partial film thickness change is observed visually. ×: Uncoated areas are observed visually.

[0092] <Evaluation of Curability> The curable composition was applied to a glass substrate to form a coating film, which was then irradiated with light from a 395 nm LED lamp, and the curability was evaluated until tackiness disappeared while changing the exposure dose. ◎ : 1J / m 2 No tack due to exposure to light less than ○: 1 J / m 2 More than 3J / m 2 No tack due to exposure to light less than △: 3J / m 2 More than 5J / m 2 No tack due to exposure to light less than ×: 5 J / m required for curing until tack disappears 2 More than 10 ...

[0093] <Refractive index measurement> The curable composition was applied to a 4-inch silicon wafer by spin coating, and then irradiated with light from a 395 nm LED lamp until the tack disappeared, yielding a cured film. The refractive index of this cured film was measured using a Model 201 (manufactured by Metricon) by the prism coupler method at a measurement wavelength of 635.8 nm.

[0094] <Evaluation of storage stability> 10 mL of the curable composition was placed in a screw tube and stored at 40° C. in the dark for 7 days. The viscosity increase rate before and after storage was calculated using formula (I) and evaluated according to the following criteria. Viscosity increase rate (%) = [viscosity after storage / viscosity before storage] x 100 ... (I) ○: 100% or more but less than 105% △: 105% or more but less than 110% ×: 110% or more

[0095] <Fabrication of organic EL elements> Several array substrates were prepared, each of which had a glass substrate ("OA-10" manufactured by Nippon Electric Glass Co., Ltd.) on which ITO transparent electrodes were formed in an array, and a 3 μm-thick planarizing layer with contact holes that exposed only a portion of the ITO transparent electrodes formed in an array. An Al film with a thickness of 100 nm was formed on the planarization layer by DC sputtering using an Al target. An ITO film with a thickness of 20 nm was formed on the Al film by DC magnetron reactive sputtering using an ITO target. In this way, a substrate with an anode layer consisting of an Al film and an ITO film was used. A resist material (the composition of Example 1 described in Japanese Patent No. 6303588) was used to form a coating film on the anode layer, and a series of treatments including exposure, development, washing with running water, air drying, and heat treatment were carried out to form a pixel-defining layer having a part of the anode layer as an opening region. The substrate on which the anode and pixel defining layer were formed was moved to a vacuum deposition chamber, which was then evacuated to 1E-4 Pa. After that, a film of molybdenum oxide (MoOx), which has hole injection properties, was formed on the substrate by resistance heating deposition using a deposition mask with a predetermined pattern at a deposition rate of 0.004 to 0.005 nm / sec, thereby forming a hole injection layer with a thickness of 1 nm. Using a deposition mask with a predetermined pattern, a hole-transporting layer of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (α-NPD) was deposited on the hole-injection layer by resistance heating deposition under the same exhaust conditions as for the hole-injection layer, forming a hole-transport layer with a thickness of 35 nm. The deposition rate was 0.2-0.3 nm / sec. Using a deposition mask with a predetermined pattern, a green light-emitting material, tris(8-quinolinolato)aluminum, was deposited on the hole-transporting layer by resistance heating deposition under the same conditions as for the hole-transporting layer, forming a 35 nm thick organic light-emitting layer at a deposition rate of 0.5 nm / sec or less. A 0.8 nm thick electron injection layer was formed on the organic light-emitting layer by resistive heating deposition of lithium fluoride under the same exhaust conditions as for the hole injection layer. The deposition rate was 0.004 nm / sec or less. Next, magnesium (Mg) and silver (Ag) were deposited on the electron injection layer by resistance heating evaporation under the same exhaust conditions as for the hole injection layer, forming a 5 nm thick first cathode layer at a deposition rate of 0.5 nm / sec or less. Subsequently, the substrate was transferred to another film-forming chamber (sputtering chamber), and a second cathode layer having a thickness of 100 nm was formed on the first cathode layer by RF sputtering using an ITO target, thereby obtaining an organic EL element for evaluation.

[0096] <Formation of thin film sealing layer> A thin film sealing layer was formed on the organic EL device obtained above by the following procedure. The organic EL device was transferred to a film formation chamber (sputtering chamber), and an inorganic sealing layer (SiNx film) with a thickness of 100 nm was formed on the cathode layer by RF sputtering using a SiNx target. Next, the organic EL device was transferred to a glove box substituted with N2, and each of the curable compositions of Examples 1 to 11 and Comparative Examples 1 to 4 was ejected in a predetermined pattern using a piezo-type inkjet printer. Next, a UniJet E110ZHD 395 nm LED lamp manufactured by Ushio Inc. was used to eject the curable compositions in a predetermined pattern at an exposure dose of 3000 mJ / cm2. 2 The curable composition was cured by irradiating light at 1000 .mu.m to form an organic sealing layer having a thickness of 10 μm. The organic EL device was transferred to a film formation chamber (sputtering chamber), and an inorganic sealing layer (SiNx film) having a thickness of 100 nm was formed on the organic sealing layer by RF sputtering using a SiNx target.

[0097] <Reliability of organic EL elements> The organic EL element with the thin film encapsulation layer formed was stored under 85°C, 85% humidity and heat conditions for 100 hours, and then the forward current was measured at 10 mA / cm. 2 A current was applied and the light emission appearance (dark spots) was observed. Based on the light emission appearance, the reliability of the organic EL device was evaluated according to the following criteria. ◎: The area ratio of the non-illuminated area is 0% or more and less than 5% ○: The area ratio of the non-illuminated area is 5% or more and less than 20% △: The area ratio of the non-illuminated area is 20% or more

[0098] [Table 2]

[0099] As shown in Table 2, the curable compositions of Examples 1 to 10 had a low viscosity of 20 mPa·s or less, and showed little coating unevenness when applied to a substrate by inkjet coating. 2 The tackiness disappeared upon exposure to light for less than 100 seconds, and the curing properties were excellent. Furthermore, the cured films formed from the curable compositions of Examples 1 to 10 exhibited a high refractive index of 1.60 or more, and the occurrence of dark spots was suppressed even when stored for long periods under high-temperature, high-humidity conditions, resulting in high reliability of the organic EL device. Among these, the cured films obtained in Examples 1 to 5 and 7 to 10 exhibited a refractive index of 1.65 or more, which was particularly high.

[0100] In contrast, the curable compositions of Comparative Examples 1 to 4 were inferior in curability to Examples 1 to 10. In particular, Comparative Examples 1 and 4, which contained the compound [A2] as the polymerizable compound but did not contain the compound [A1] and the compound [A3], were rated as "x" for curability and also rated as "x" for device reliability. Furthermore, Comparative Example 2, which contained the compound [A2] and the compound [A3] as the polymerizable compound but did not contain the compound [A1], was rated as "○" for curability but rated as "△" for device reliability, and was inferior to Examples 1 to 10. The curable composition of Comparative Example 3 was solid, so a cured film could not be formed by inkjet coating.

Claims

1. [A1] an ethylenically unsaturated group and a compound represented by the following formula (1): 【Chemistry 1】 (In formula (1), X １ is an oxygen atom, a sulfur atom, or a selenium atom. "*" represents a bond.) groups represented by -S(=O)- and -S(=O) ２ - a compound having at least one group [F1] selected from the group consisting of -, wherein the group [F1] has a partial structure adjacent to the carbon-carbon unsaturated bond in the ethylenically unsaturated group, [A2] A compound having an ethylenically unsaturated group and a thioether group, wherein the thioether group has a partial structure adjacent to a carbon-carbon unsaturated bond in the ethylenically unsaturated group, and [B] a radical polymerization initiator, Including, A curable composition, wherein the total number (NA) of ethylenically unsaturated groups contained in the compound [A1] and the total number (NB) of ethylenically unsaturated groups contained in the compound [A2] contained in the composition is, in molar ratio, (NA):(NB)=1:0.5 to 1:1.

5.

2. The curable composition of claim 1 , which is for inkjet application.

3. The curable composition according to claim 1 or 2, which is a sealant for an organic EL device.

4. [A1] an ethylenically unsaturated group and a compound represented by the following formula (1): 【Chemistry 2】 (In formula (1), X １ is an oxygen atom, a sulfur atom, or a selenium atom. "*" represents a bond.) groups represented by -S(=O)- and -S(=O) ２ - a compound having at least one group [F1] selected from the group consisting of -, wherein the group [F1] has a partial structure adjacent to the carbon-carbon unsaturated bond in the ethylenically unsaturated group, [A2] A compound having an ethylenically unsaturated group and a thioether group, wherein the thioether group has a partial structure adjacent to a carbon-carbon unsaturated bond in the ethylenically unsaturated group, and [B] a radical polymerization initiator, and a curable composition for inkjet application.

5. [A1] an ethylenically unsaturated group and a compound represented by the following formula (1): 【Transformation 3】 (In formula (1), X １ is an oxygen atom, a sulfur atom, or a selenium atom. "*" represents a bond.) groups represented by -S(=O)- and -S(=O) ２ - a compound having at least one group [F1] selected from the group consisting of -, wherein the group [F1] has a partial structure adjacent to the carbon-carbon unsaturated bond in the ethylenically unsaturated group, [A2] A compound having an ethylenically unsaturated group and a thioether group, wherein the thioether group has a partial structure adjacent to a carbon-carbon unsaturated bond in the ethylenically unsaturated group, and [B] a radical polymerization initiator, The curable composition is a sealant for an organic EL device.

6. The curable composition according to any one of claims 1 to 5, wherein the compound [A1] is at least one selected from the group consisting of compounds represented by the following formula (3-1) and compounds represented by the following formula (3-2): 【Chemistry 4】 (In formula (3-1), R １ is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms. １ is an oxygen atom, a sulfur atom, or a selenium atom. ２ is a monovalent organic group having 1 to 20 carbon atoms. r is an integer of 1 to 3. When r is 2 or 3, multiple R １ are the same or different, and when r is 1, a plurality of R ２ are the same or different. In formula (3-2), R １ is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms. １ is -S(=O)- or -S(=O) ２ - is. R ３ is a t-valent organic group having 1 to 20 carbon atoms. t is an integer of 1 to 4. When t is 2 or more, multiple R １ are the same or different, and multiple Y １ are the same or different.)

7. The curable composition according to any one of claims 1 to 6, having a viscosity measured using an E-type viscometer at 25°C and 20 rpm in the range of 1.0 to 40.0 mPa·s.

8. The curable composition according to any one of claims 1 to 7, wherein the compound [A2] has an aromatic ring and a partial structure in which a thioether group adjacent to a carbon-carbon unsaturated bond in an ethylenically unsaturated group is bonded to the aromatic ring.

9. The curable composition according to any one of claims 1 to 8, wherein the compound [A2] is at least one selected from the group consisting of a compound represented by the following formula (7-1), a compound represented by the following formula (7-2), a compound represented by the following formula (7-3), a compound represented by the following formula (7-4), and a compound represented by the following formula (7-5): 【Transformation 5】 (In formulas (7-1) to (7-5), R １２ and R １３ are each independently a halogen atom or an alkyl group having 1 to 6 carbon atoms. １４ , R １５ and R １６ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms. a1 and a2 are each independently an integer of 0 to 4. a3 and a5 are each independently an integer of 0 to 5. a4 and a6 are each independently an integer of 0 to 7, provided that a3+a5≦5 and a4+a6≦7 are satisfied. R １２ When there are a plurality of R １２ are the same or different, R １３ When there are a plurality of R １３ are the same or different, R １５ When there are a plurality of R １５ are the same or different.)

10. The curable composition according to any one of claims 1 to 9, wherein the content of the organic solvent is 0% by mass or more and 3% by mass or less.

11. A cured film formed from the curable composition according to any one of claims 1 to 10.

12. An organic EL device having a light-emitting layer sealed with the cured film according to claim 11.

13. A method for producing an organic EL element, comprising the steps of applying the curable composition according to any one of claims 1 to 10 to a surface of a substrate on which an organic light-emitting layer has been formed, and curing the curable composition by irradiating with radiation, thereby forming a sealing structure.

14. The method for producing an organic EL element according to claim 13 , wherein the curable composition is applied to the surface on which the light-emitting layer is to be formed by inkjet coating.

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