Curable composition, cured product, organic electroluminescent display element, and method for sealing organic electroluminescent element part

Abstract

Disclosed is a curable composition for use in sealing of an organic electroluminescent element part. The curable composition contains one or more compounds A that are represented by general formula (1) and have a point group of Cs or C2v, and a (meth)acrylic acid ester compound that has a molecular weight of 500 or less. At least one of the compounds A is a compound in which at least one of Ra to Rh is a (meth)acryloyl thioxy group. Also disclosed are: a cured product which is obtained from this composition; an OLED display element; and a method for sealing an OLED element part. In the formula, Ra to Rh each represent a hydrogen atom, an alkylsulfanyl group having 1 to 10 carbon atoms, or a (meth)acryloyl thioxy group.

Description

Curable composition, cured product, organic electroluminescent display element, and method for sealing organic electroluminescent element portion

[0001] The present invention relates to a curable composition, a cured product, an organic electroluminescent display element, and a method for sealing an organic electroluminescent element portion.

[0002] In recent years, demand for optical components requiring a high refractive index has increased, and the use of resins exhibiting a high refractive index (high refractive index resins) as materials for such optical components has been investigated. High refractive index resins can be obtained by polymerizing monomers exhibiting a high refractive index (high refractive index monomers). Known examples of high refractive index monomers include aromatic ring skeleton-containing monomers such as benzene rings and naphthalene rings. However, naphthalene skeleton-containing monomers have high crystallinity due to the naphthalene skeleton, which limits their ease of handling. To address this issue, for example, Patent Document 1 describes 1,6-naphthalenedithiol and its derivatives, which combine a high refractive index with high solubility (compatibility). Patent Document 2 also describes a curable composition containing p-thiophenylbenzyl acrylate represented by Formula I, a specific multifunctional (meth)acrylate, and a photoinitiator, where the resulting cured product has a high refractive index, is optically transparent, and is thermally stable. Patent Document 2 describes that an optical member exhibiting a high refractive index is required as a sealing material for an organic electroluminescence element portion (OLED element portion).

[0003] International Publication No. 2023 / 058449 Special Publication No. 2021-523281

[0004] As described in Patent Document 2, optical components used as encapsulating materials for OLED elements are required to have a high refractive index. That is, in thin-film encapsulation techniques for OLED elements, a barrier layer is provided to prevent the permeation of water vapor, oxygen gas, and the like to prevent degradation of the OLED element due to these factors. Because the inorganic barrier layer used as a barrier layer exhibits a high refractive index, a high refractive index is also required for the encapsulating material used adjacent to the inorganic barrier layer to reduce interfacial reflections due to differences in refractive index between adjacent layers. One known thin-film encapsulation technique for OLED elements involves printing a curable composition containing a high-refractive-index monomer using an inkjet device to form a coating film, and then curing the resulting coating film to form a thin-film (cured film) encapsulant (the inkjet method). This inkjet method requires low viscosity in order to form a coating film with a uniform thickness (e.g., ease of handling). However, although aromatic ring skeleton-containing monomers are expected to have a high refractive index, they often exhibit high viscosity, and therefore it is necessary to achieve both a high refractive index and low viscosity at a high level. Furthermore, because aromatic ring skeleton-containing monomers have high crystallinity, microcrystals of the aromatic ring skeleton-containing monomer may be generated during droplet ejection in the process of forming a coating film by the inkjet method, which may result in a large number of point-like defects in the obtained thin film (cured film). Therefore, from the viewpoint of suppressing deterioration of the OLED element portion and from the viewpoint of uniform deposition of an inorganic barrier layer on the obtained thin film, it is also required that point-like defects in the film be suppressed (hereinafter referred to as "thin film printability").

[0005] The above-mentioned Patent Document 1 describes that crystalline 1,6-naphthalenedithiol and its derivatives have superior solubility in organic solvents, copolymerization components, etc., and compatibility with polymers and resins, compared to naphthalene disubstituted compounds other than those at the 1,6-position. However, there is no description of the application of compositions containing 1,6-naphthalenedithiol or its derivatives to thin-film encapsulation technology for OLED element parts. Furthermore, it has been found that the curable composition described in the above-mentioned Patent Document 2 generates an unacceptable level of point-like defects in the thin film obtained by the inkjet method, and the refractive index of the cured product and the low viscosity of the composition are not sufficiently compatible.

[0006] An object of the present invention is to provide a curable composition that has excellent thin-film printability, low viscosity before the curing reaction, and can achieve a high refractive index in the resulting cured product, and is suitable for use in sealing organic electroluminescent device components. Another object of the present invention is to provide a cured product obtained from the curable composition, and an organic electroluminescent display device containing the cured product. Another object of the present invention is to provide a method for sealing organic electroluminescent device components.

[0007] The above-mentioned problems of the present invention have been solved by the following means: <1> A curable composition for use in sealing an organic electroluminescence element, the curable composition being represented by the following general formula (1) and belonging to the point group C ｓ or C ２ｖ and a (meth)acrylic acid ester compound having a molecular weight of 500 or less, wherein at least one of the compounds A is ａ ~R ｈ A curable composition, wherein at least one of the above is a compound having a (meth)acryloylthioxy group. In the above formula, R ａ ~R ｈ represents a hydrogen atom, an alkylsulfanyl group having 1 to 10 carbon atoms, or a (meth)acryloylthioxy group. <2> The curable composition according to <1>, which contains two or more types of the compound A. <3> The curable composition according to <2>, which contains three or more types of the compound A. <4> All point groups of the compound A are Cｓ <5> The curable composition according to any one of <2> to <4>, wherein the content of each compound A is 10% by mass or more relative to 100% by mass of the total amount of the compounds A. <6> The curable composition according to any one of <1> to <5>, wherein the minimum viscosity in a temperature range of 25 to 50°C is 20 cP or less, and the refractive index of a cured product obtained from the curable composition at 25°C and a wavelength of 589 nm is 1.550 or more. <7> A cured product obtained from the curable composition according to any one of <1> to <6>. <8> An organic electroluminescent display element comprising a sealing film made of the cured product according to <7>, a barrier layer, and an organic electroluminescent element element. <9> A method for sealing an organic electroluminescent element element, comprising sealing the organic electroluminescent element element with a cured product obtained from the curable composition according to any one of <1> to <6>.

[0008] In the present invention, when there are multiple substituents or linking groups, etc., represented by a specific symbol or formula (hereinafter referred to as substituents, etc.), or when multiple substituents, etc. are specified simultaneously, unless otherwise specified, the respective substituents, etc. may be the same or different from each other (regardless of the presence or absence of the expression "independently," the respective substituents, etc. may be the same or different from each other). This also applies to the specification of the number of substituents, etc. Furthermore, when multiple substituents, etc., are adjacent to each other (especially when they are adjacent), they may be linked to each other to form a ring, unless otherwise specified. Furthermore, unless otherwise specified, rings, such as alicyclic rings, aromatic rings, and heterocyclic rings, may be further condensed to form a fused ring. In the present invention, unless otherwise specified, with respect to double bonds, when E- and Z-configurations exist in a molecule, they may be either one of them, or a mixture thereof. Furthermore, in the present invention, unless otherwise specified, when a compound has one or more asymmetric carbons, the stereochemistry of such asymmetric carbons can each independently be either an (R) or (S) configuration. As a result, the compound may be a mixture of stereoisomers such as optical isomers or diastereoisomers, or may be a racemate. However, when counting the types of compound A, the types of structural isomers are counted, and stereoisomers are not counted as different types. Furthermore, in the present invention, the expressions for compounds and monomers include those in which a part of the structure has been changed, as long as the effects of the present invention are not impaired. In the present invention, for substituents (similar to linking groups and rings) that are not specified as substituted or unsubstituted, it means that the group may have any substituent, as long as the desired effects are not impaired. For example, when referring to an "alkyl group," it means that both an unsubstituted alkyl group and a substituted alkyl group are included. For example, R in general formula (1) ａ ~R ｈThe alkyl group in the alkylsulfanyl group having 1 to 10 carbon atoms, which can be represented by the formula (I), may have a substituent, as described below. In the present invention, when the number of carbon atoms of a certain group is specified, this number of carbon atoms means the number of carbon atoms of the entire group, unless otherwise specified in the present invention or this specification. In other words, when this group further has a substituent, it means the total number of carbon atoms including the substituent.

[0009] In the present invention, when describing physical properties and the like by showing a numerical range, if the upper and lower limits of the numerical range are described separately, any of the upper and lower limits can be appropriately combined to form a specific numerical range. On the other hand, when describing multiple numerical ranges represented using "to", the upper and lower limits forming the numerical range are not limited to the combination of the specific upper and lower limits written before and after "to" as a specific numerical range, and can be any numerical range obtained by appropriately combining the upper and lower limits of each numerical range. Note that in the present invention, a numerical range represented using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits. In the curable composition of the present invention, each component may be used alone or in combination of two or more types, unless otherwise specified. The same applies to the cured product and organic electroluminescent display element obtained from the curable composition of the present invention.

[0010] In the present invention, "(meth)acrylate" refers to either or both of acrylate and methacrylate, "(meth)acrylic acid" refers to either or both of acrylic acid and methacrylic acid, and "(meth)acryloyl" refers to either or both of acryloyl and methacryloyl. Monomers in the present invention are distinguished from oligomers and polymers based on molecular weight, and compounds having a weight-average molecular weight of 1,000 or less are called monomers.

[0011] The curable composition of the present invention exhibits excellent thin film printability, making it possible to obtain a cured product that is less likely to produce point defects in the film. Moreover, the curable composition has low viscosity and excellent handleability, while also achieving a high refractive index for the resulting cured product. The cured product of the present invention and the cured product contained in the organic electroluminescent display element of the present invention can exhibit a high refractive index. According to the method for sealing an organic electroluminescent element portion of the present invention, point defects in the film are suppressed, and the organic electroluminescent element portion can be sealed with a thin film that exhibits a high refractive index.

[0012] [Curable Composition] The curable composition of the present invention is a curable composition for use in sealing an organic electroluminescence element, and is represented by the following general formula (1) and the point group is C ｓ or C ２ｖ and a (meth)acrylic acid ester compound having a molecular weight of 500 or less, wherein at least one of the compounds A is ａ ~R ｈ and at least one of the above is a (meth)acryloylthioxy group.

[0013] In the present invention, the curable composition means a composition that has curability and can give a cured product (resin) by a curing reaction.

[0014] The compound A contained in the curable composition of the present invention is a compound represented by the general formula (1) below, which has a substituent R on a naphthalene ring. ａ ~R ｈ Among naphthalene compounds which may have an alkylsulfanyl group or a (meth)acryloylthioxy group having 1 to 10 carbon atoms as the alkyl group, ｓ or C ２ｖ In the curable composition of the present invention, at least one of the compounds A is a substituted naphthalene compound having a substituent R on the naphthalene ring. ａ ~R ｈThe curable composition of the present invention contains one or more substituted naphthalene compounds (compounds A) having the above-described specific chemical structure and specific point group in combination with a (meth)acrylic acid ester compound having a molecular weight of 500 or less. Although all of the compounds A exhibit high crystallinity, excellent thin-film printability is achieved when a thin-film cured product having a thickness of several micrometers to several tens of micrometers is produced, with almost no point-like defects. Furthermore, the curable composition has a low viscosity, and the resulting cured product can achieve a high refractive index.

[0015] The point group that the compound represented by the general formula (1) described later can take is C ｓ or C ２ｖ , and unsubstituted naphthalene adopts D ２ｈ Besides, C ２ｈ Here, C ２ｖ is C ２ It has a rotation axis and a vertical mirror plane, and C ２ｈ is C ２ Since it has a rotation axis and a horizontal plane of symmetry, C ２ｖ and C ２ｈ However, among the compounds represented by the general formula (1) described below, C ２ｈ When the ink contains C, thin film printability is poor and low viscosity cannot be achieved. ｓ and C ２ｖ It has been found that, for the first time, excellent thin-film printability and low viscosity can be achieved by combining at least one selected from the following compounds with a (meth)acrylic acid ester compound having a molecular weight of 500 or less.

[0016] The components contained in the curable composition of the present invention will be described below in order.

[0017] <Compound A> The compound A is represented by the following general formula (1) and has a point group C ｓ or C ２ｖ It is a compound in which

[0018] (Compound represented by general formula (1)) In the above formula, R ａ~R ｈ represents a hydrogen atom, an alkylsulfanyl group having 1 to 10 carbon atoms, or a (meth)acryloylthioxy group.

[0019] R ａ ~R ｈ The alkyl group in the alkylsulfanyl group (alkyl group -S-) having 1 to 10 carbon atoms, which can be taken as R, may be either linear or branched, and the number of carbon atoms in the alkyl group may be 1 to 10, preferably 1 to 7, more preferably 1 to 5, and even more preferably 1 to 3. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a 1-methylbutyl group, a 3-methylbutyl group, a hexyl group, a 1-methylpentyl group, a 4-methylpentyl group, a heptyl group, a 1-methylhexyl group, a 5-methylhexyl group, a 2-ethylhexyl group, an octyl group, a 1-methylheptyl group, a nonyl group, a 1-methyloctyl group, a nonyl group, and a decyl group, and a methyl group or an ethyl group is preferred. R ａ ~R ｈ The alkyl group in the alkylsulfanyl group having 1 to 10 carbon atoms which can be taken as R may have a substituent, and examples of the alkyl group having such a substituent include a halogenated alkyl group and a hydroxyalkyl group. Examples of the halogen atom constituting the halogenated alkyl group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R ａ ~R ｈ The alkylsulfanyl group having 1 to 10 carbon atoms that can be taken as the alkylsulfanyl group is preferably a methylsulfanyl group or an ethylsulfanyl group.

[0020] R ａ ~R ｈ Among the (meth)acryloylthioxy groups that can be taken as above, the acryloylthioxy group is a group represented by the following formula (Pol-1), and the methacryloylthioxy group is a group represented by the following formula (Pol-2). In the following formulas, * indicates a bond.

[0021]

[0022] R ａ~R ｈ Among the eight groups, the number of groups that are alkylsulfanyl groups or (meth)acryloylthioxy groups having 1 to 10 carbon atoms is determined based on the point group of the compound represented by the general formula (1) being C ｓ or C ２ｖ As long as R ａ ~R ｈ Among the eight groups, the number of groups that are (meth)acryloylthioxy groups is, for example, preferably 0 to 4, and more preferably 0 to 3, from the viewpoint of obtaining a good cured product. However, at least one of the compounds A contained in the curable composition of the present invention is ａ ~R ｈ and at least one of the above is a (meth)acryloylthioxy group.

[0023] (Point Group) The compound A is represented by the general formula (1) and has a point group C ｓ or C ２ｖ The point group of the compound A is C ｓ In addition, the compound represented by the general formula (1) is preferably ａ ~R ｈ The structure includes unsubstituted naphthalene, where is a hydrogen atom. However, unsubstituted naphthalene has a point group of D ２ｈ Therefore, it is not included in the above-mentioned compound A. Therefore, the above-mentioned compound A is a substituted naphthalene compound having at least one alkylsulfanyl group or (meth)acryloylthioxy group having 1 to 10 carbon atoms as a substituent.

[0024] In the compound A, a monosubstituted compound having one substituent (hereinafter referred to as "substituent A") selected from an alkylsulfanyl group having 1 to 10 carbon atoms and a (meth)acryloylthioxy group, the position where the substituent A is present is R ａ and R ｂ In the case of a disubstituted compound having two substituents A among the compound A, the position where the substituent A is present may be any of R ａ and R ｂ , Rａ and R ｃ , R ａ and R ｄ , R ａ and R ｆ , R ａ and R ｇ , R ａ and R ｈ , R ｂ and R ｃ , or R ｂ and R ｇ In the compound A, in a tri-substituted compound having three substituents A, the position where the substituent A is present is preferably R ａ , R ｃ and R ｆ The combination of R ａ , R ｃ and R ｇ or a combination of R ｂ , R ｃ and R ｇ In the compound A, in a tetrasubstituted compound having four substituents A, the position where the substituent A is present is preferably a combination of R ａ , R ｃ , R ｆ and R ｇ or a combination of R ａ , R ｃ , R ｆ and R ｈ The combination is preferred.

[0025] Preferred specific examples of Compound A are listed below, but the present invention is not limited to these compounds. In the following, Me means a methyl group, and * means a bond. In addition, point groups are written in parentheses below the compound numbers.

[0026]

[0027]

[0028] The molecular weight of the compound A is preferably 174 to 820, more preferably 174 to 670, and even more preferably 174 to 530.

[0029] The compound A can be synthesized by a conventional method. For example, it can be synthesized with reference to the synthesis methods described in JP-A-2013-155118 (Sumitomo Seika Chemicals) and JP-A-3-170456 (Sumitomo Seika Chemicals). Furthermore, it can be synthesized with reference to the methods described in the examples, as appropriate.

[0030] The curable composition of the present invention contains one or more of the above-mentioned compounds A. As shown in the examples below, the above-mentioned compounds A are compounds with very high crystallinity when used alone, but when the curable composition of the present invention contains two or more of the above-mentioned compounds A, it is preferable because the thin film printability can be further improved. In particular, it is preferable that the curable composition of the present invention contains three or more of the above-mentioned compounds A from the viewpoint of further improving the thin film printability. When the curable composition of the present invention contains two or more of the above-mentioned compounds A, there are no particular restrictions on the combination of two or more (preferably three or more) of the above-mentioned compounds A contained in the curable composition of the present invention, and for example, ｓ There may be two or more types of compound A, and the point group is C ２ｖ There may be two or more types of compound A, and the point group is C ｓ and one or more compounds A having a point group C ２ｖ From the viewpoint of further improving thin film printability, the point groups of the compound A contained in the curable composition of the present invention may be such that all of the point groups of the compound A are C ｓ When the curable composition of the present invention contains two or more of the compounds A, the content of each compound A in 100% by mass of the total of the compounds A (meaning "the sum of all of the compounds A contained in the curable composition of the present invention") is not particularly limited, and can be, for example, 5% by mass or more for each, preferably 7% by mass or more for each, and from the viewpoint of further improving thin film printability, more preferably 10% by mass or more for each. The upper limit is determined appropriately depending on how many types of compounds A are contained in the curable composition of the present invention, so that the lower limit of each compound A is 10% by mass or more.

[0031] Examples of the compound A contained in the curable composition of the present invention include R ａ and R ｆ a disubstituted compound having two substituents A in R ｂ and R ｇ Disubstituted compounds having two substituents A in R ａ , R ｃ and R ｆ In addition, in the combination of these two or more types, R ａ and R ｆ a combination of two or more disubstituted compounds having two substituents A in R ｂ and R ｇ a combination of two or more disubstituted compounds having two substituents A in R ａ , R ｃ and R ｆ Also included is a combination of two or more tri-substituted compounds each having three substituents A in R ａ and R ｆ a combination of two or more disubstituted compounds having two substituents A in R ｂ and R ｇ a combination of two or more disubstituted compounds having two substituents A in R ａ and R ｆ A disubstituted compound having two substituents A in R ｂ and R ｇ and a disubstituted compound having two substituents A in R ａ and R ｆ A disubstituted compound having two substituents A in R ｂ and R ｇ and at least one disubstituted compound having two substituents A in R ａ , R ｃ and R ｆ and a tri-substituted compound having three substituents A. In the descriptions of these preferred compounds A to more preferred compounds A, the descriptions of the substituents, point groups and content in general formula (1) above can be preferably applied to the substituents, point groups and content in general formula (1), respectively.

[0032] The total content of the compound A in the curable composition of the present invention can be, for example, 25 to 99 mass%, preferably 30 to 97 mass%, more preferably 35 to 95 mass%, still more preferably 45 to 95 mass%, and particularly preferably 50 to 93 mass%.

[0033] <(Meth)acrylic acid ester compound> The curable composition of the present invention contains a (meth)acrylic acid ester compound having a molecular weight of 500 or less (excluding the above-mentioned compound A; hereinafter, also simply referred to as "(meth)acrylic acid ester compound B"). In addition to the above-mentioned (meth)acrylic acid ester compound B, the curable composition of the present invention may also contain a (meth)acrylic acid ester compound having a molecular weight of more than 500 (excluding the above-mentioned compound A; hereinafter, also simply referred to as "(meth)acrylic acid ester compound C"). Examples of the (meth)acrylic acid ester compound include monofunctional mono(meth)acrylic acid ester compounds, difunctional di(meth)acrylic acid ester compounds, and trifunctional or higher polyfunctional (meth)acrylic acid ester compounds, depending on the number of functional (meth)acryloyl groups. Specific examples of (meth)acrylic acid ester compounds are described below. Note that the following specific examples of (meth)acrylic acid ester compounds are classified as (meth)acrylic acid ester compounds B or (meth)acrylic acid ester compounds C, depending on whether they have a molecular weight of 500 or less or more than 500.

[0034] Specific examples of the mono(meth)acrylic acid ester compound include tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 1-ethoxyethyl (meth)acrylate, butadiene, ethoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethyl diglycol (meth)acrylate, cyclic trimethylolpropane formal mono(meth)acrylate, imide (meth)acrylate, isoamyl (meth)acrylate, ethoxylated succinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, ω-carboxypolycaprolactone mono(meth)acrylate, cyclohexyl (meth)acrylate acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, caprolactone (meth)acrylate, methoxypolyethylene glycol (350) mono(meth)acrylate, methoxypolyethylene glycol (550) mono(meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate , tribromophenyl (meth)acrylate, ethoxylated tribromophenyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, an ethylene oxide adduct of 2-phenoxyethyl (meth)acrylate, a propylene oxide adduct of 2-phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and 3-(meth)acryloyloxymethyl cyclohexene oxide.Specific product names and sources of the mono(meth)acrylic acid ester compounds include ethoxylated orthophenylphenol acrylate (NK Ester A-LEN-10, manufactured by Shin-Nakamura Chemical Co., Ltd.) and m-phenoxybenzyl acrylate (Light Acrylate POB-A, manufactured by Kyoeisha Chemical Co., Ltd.).

[0035] Specific examples of the di(meth)acrylic acid ester compound include di(meth)acrylates of diols and di(meth)acrylates of (poly)alkylene glycols. Specific product names and sources of di(meth)acrylic acid ester compounds include 1,6-hexanediol diacrylate (NK Ester A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,6HX-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,9-nonanediol diacrylate (NK Ester A-NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,9ND-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,10-decanediol diacrylate (NK Ester A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), neopentyl glycol diacrylate (NK Ester A-NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate NP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethylene glycol diacrylate (SR206NS, manufactured by Arkema), polyethylene glycol diacrylate (NK Ester A-400, Shin-Nakamura Chemical Co., Ltd.), polypropylene glycol diacrylate (NK Ester APG-400, Shin-Nakamura Chemical Co., Ltd.), 1,3-butanediol dimethacrylate (NK Ester BG, Shin-Nakamura Chemical Co., Ltd.), 1,4-butanediol dimethacrylate (NK Ester BD, Shin-Nakamura Chemical Co., Ltd.), 1,6-hexanediol dimethacrylate (NK Ester HD-N, Shin-Nakamura Chemical Co., Ltd.), 1,9-nonanediol dimethacrylate (NK Ester NOD-N, Shin-Nakamura Chemical Co., Ltd.), 1,10-decanediol dimethacrylate (NK Ester DOD-N, Shin-Nakamura Chemical Co., Ltd.), 1,12-dodecanediol dimethacrylate (SR262, Sartomer), neopentyl glycol dimethacrylate (NK Ester NPG, Shin-Nakamura Chemical Co., Ltd.), and the like.

[0036] Specific product names and sources of polyfunctional (meth)acrylic acid ester compounds include trifunctional (meth)acrylic acid ester compounds such as trimethylolpropane triacrylate (NK Ester A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate TMP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethoxylated trimethylolpropane triacrylate (NK Ester A-TMPT-EO, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated glycerin triacrylate (NK Ester A-GLY-6E, manufactured by Shin-Nakamura Chemical Co., Ltd.), and propoxylated glycerin triacrylate (NK Ester A-GLY-3P, manufactured by Shin-Nakamura Chemical Co., Ltd.); Examples of suitable (meth)acrylic acid ester compounds include tetrafunctional (meth)acrylic acid ester compounds such as pentaerythritol tetraacrylate (NK Ester A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated pentaerythritol tetraacrylate (NK Ester ATM-4E, manufactured by Shin-Nakamura Chemical Co., Ltd.), and ditrimethylolpropane tetraacrylate (NK Ester AD-TMP-L, manufactured by Shin-Nakamura Chemical Co., Ltd.); pentafunctional (meth)acrylic acid ester compounds such as dipentaerythritol pentaacrylate (M-402, manufactured by Toagosei Co., Ltd.); and hexafunctional (meth)acrylic acid ester compounds such as dipentaerythritol hexaacrylate (GM66G0H, manufactured by Kokusei Chemical Co., Ltd.).

[0037] The (meth)acrylic acid ester compound B is preferably a mono(meth)acrylic acid ester compound or a di(meth)acrylic acid ester compound.

[0038] The molecular weight of the (meth)acrylic acid ester compound B is 500 or less. By containing the (meth)acrylic acid ester compound B having a molecular weight of 500 or less in combination with the compound A, the curable composition of the present invention can achieve excellent thin film printability and a high refractive index while adjusting the viscosity of the composition to a low viscosity. The molecular weight of the (meth)acrylic acid ester compound B is preferably 130 to 500, more preferably 140 to 480. Furthermore, the molecular weight of the (meth)acrylic acid ester compound C is preferably more than 500 and 700 or less.

[0039] There is no particular limitation on the method for obtaining the (meth)acrylic acid ester compound, and the compound may be commercially available or synthesized by a conventional method.

[0040] The content of the (meth)acrylic acid ester compound B in the curable composition of the present invention can be, for example, 1 to 75 mass%, preferably 3 to 70 mass%, more preferably 5 to 65 mass%, even more preferably 5 to 55 mass%, and particularly preferably 7 to 50 mass%.

[0041] In the curable composition of the present invention, the content ratio of the compound A to the (meth)acrylic acid ester compound B (i.e., compound A:(meth)acrylic acid ester compound B, hereinafter referred to as A:B) can be, on a mass basis, A:B=25-99:1-75, preferably A:B=30-97:3-70, more preferably A:B=35-95:5-65, still more preferably A:B=45-95:5-55, and particularly preferably A:B=50-93:7-50.

[0042] The curable composition of the present invention may contain one type or two or more types of (meth)acrylic acid ester compounds B. When two or more types of (meth)acrylic acid ester compounds B are contained, the total content thereof is preferably within the above range.

[0043] When the curable composition of the present invention contains a (meth)acrylic acid ester compound C, the content of the (meth)acrylic acid ester compounds C (when two or more types are contained, the total content) is not particularly limited and can be appropriately adjusted, and can be, for example, 0.1 to 30 mass%.

[0044] The effective composition of the present invention is a compound represented by the above-mentioned general formula (1), and the point group is C ２ｈThe curable composition of the present invention may further contain a compound (hereinafter referred to as compound D) represented by the formula: within a range that does not impair the effects of the present invention. In this case, the total content of compound A in the curable composition of the present invention described above shall be read as the total content of compound A and compound D. However, the proportion of the content of compound D in the total content (100% by mass) of compound A and compound D is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 10% by mass or less, and particularly preferably 3% by mass or less.

[0045] <Other Components> The curable composition of the present invention may further contain other components in addition to the above-described compound A, (meth)acrylic acid ester compound B, and optionally contained (meth)acrylic acid ester compound C. Examples of other components include a photoradical polymerization initiator.

[0046] (Photoradical polymerization initiator) The curable composition of the present invention preferably contains a photoradical polymerization initiator. The curable composition of the present invention can obtain a cured product exhibiting a high refractive index by photopolymerization due to the action of the photoradical polymerization initiator. As the photoradical polymerization initiator, compounds commonly used as photoradical polymerization initiators can be used appropriately depending on the conditions of the photopolymerization (photocuring) step described below, and specifically the following compounds can be used. For example, 1,2-diphenylethanedione, methylphenyl glyoxylate; α-acylphosphine compounds such as bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,4,4-trimethylpentylphosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and ethylphenyl(2,4,6-trimethylbenzoyl)phosphinate (also known as (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide). α-hydroxyketone compounds such as 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methylpropan-1-one; benzyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethan-1-one; α-aminoketone compounds such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone;Examples of oxime ester compounds include 1-[4-(phenylthio)phenyl]octane-1,2-dione 2-(O-benzoyloxime) (available from BASF Japan under the trade name Irgacure OXE01), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone O-acetyloxime (available from BASF Japan under the trade name Irgacure OXE02), Irgacure OXE03 and Irgacure OXE04 (all trade names, available from BASF Japan), and ADEKA ARCLES N-1919T, ADEKA ARCLES NCI-831E, ADEKA ARCLES NCI-930 and ADEKA ARCLES NCI-730 (all trade names, available from ADEKA).

[0047] Among these, in the present invention, as the photoradical polymerization initiator, 1-hydroxycyclohexyl phenyl ketone (available from BASF Japan Ltd. under the trade name of Irgacure 184), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (available from BASF Japan Ltd. under the trade name of Irgacure 819), (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (available from BASF Japan Ltd. under the trade name of Irgacure TPO), 2,2-dimethoxy-1,2-diphenylethane-1,2-diol, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (available from BASF Japan Ltd. under the trade name of Irgacure TPO), ... 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, ethylphenyl(2,4,6-trimethylbenzoyl)phosphinate (available from BASF Japan as Irgacure TPO-L (trade name) or from ADEKA Corporation as Adeka Arcles NCI-831E (trade name)) can be preferably used. The photoradical polymerization initiator may contain one type, or two or more types.

[0048] When a photoradical polymerization initiator is contained, the content of the photoradical polymerization initiator in the curable composition of the present invention is preferably 0.1 to 10.0 mass%, more preferably 0.5 to 7.0 mass%, and even more preferably 0.7 to 5.0 mass%.

[0049] As long as it does not deviate from the spirit of the present invention, the curable composition of the present invention may contain polymers or monomers other than the above-mentioned components, leveling agents (surface conditioners), dispersants, plasticizers, heat stabilizers, release agents, solvents, etc. Examples of leveling agents include silicone surfactants, fluorine surfactants, and acrylic surfactants described in paragraphs 0044 to 0046 of JP-A No. 2024-500396. When a leveling agent is contained, the content of the leveling agent in the curable composition of the present invention is preferably 0.1 to 1 mass%.

[0050] The minimum viscosity of the curable composition of the present invention in a temperature range of 25 to 50°C is preferably 40 mPa·s or less, more preferably 20 mPa·s or less, from the viewpoints of improving handleability when forming a cured product, particularly realizing inkjettable physical properties and improving coating properties (liquid spreadability after inkjetting), and forming a higher quality cured product. There is no particular restriction on the lower limit, but a viscosity of 1 mPa·s or more is practical. Note that 1 cP is 1 mPa·s. The minimum viscosity of the curable composition in a temperature range of 25 to 50°C can be measured using a rheometer (for example, trade name: HAAKE RheoStress 6000, manufactured by Thermo Fisher Scientific) at a shear rate of 10 s －１ The viscosity is the minimum value measured in the temperature range of 25 to 50°C under the conditions above.

[0051] The curable composition of the present invention can be used to produce a cured product that is required to have a high refractive index. In particular, the curable composition of the present invention has low viscosity and excellent thin-film printability, and is therefore used as a material for sealing organic electroluminescence (OLED) element parts, preferably as a material for thin-film sealing of OLED element parts, and is preferably used to produce a cured product that exhibits a high refractive index.

[0052] [Method for Preparing Curable Composition] The method for preparing the curable composition of the present invention is not particularly limited, as long as the curable composition of the present invention contains one or more of the compounds A and the (meth)acrylic acid ester compound B. For example, the curable composition is preferably prepared by mixing one or more of the compounds A with the (meth)acrylic acid ester compound B. Furthermore, mixing of one or more of the compounds A with the (meth)acrylic acid ester compound B may be carried out in the presence of an organic solvent. For example, a mixed solution of one or more of the compounds A and the (meth)acrylic acid ester compound B can be prepared by stirring and mixing one or more of the compounds A with the (meth)acrylic acid ester compound B in the presence of an organic solvent, and then removing the organic solvent from the resulting mixed solution. The organic solvent is preferably one in which one or more of the compounds A and the (meth)acrylic acid ester compound B are soluble. Examples of the organic solvent include hydrocarbon solvents such as aromatic hydrocarbon solvents such as toluene, halogenated hydrocarbon solvents such as chlorinated hydrocarbon solvents such as methylene chloride and chloroform, alcohol solvents such as methanol, ether solvents such as cyclic ether solvents such as tetrahydrofuran, epihalohydrin solvents such as epichlorohydrin, glycol ether acetate solvents such as (poly)alkylene glycol monoalkyl ether acetate, ester solvents such as ethyl acetate, amide solvents such as N,N-dimethylformamide, and urea solvents. The organic solvent can be removed by a conventional method, for example, by distillation under heating and / or reduced pressure. Components other than the compound A and the (meth)acrylic acid ester compound B may be added at the stage of mixing the one or more compounds A and the (meth)acrylic acid ester compound B, or may be added separately and mixed after preparing a mixed solution of the one or more compounds A and the (meth)acrylic acid ester compound B. For example, it is preferable to mix the above-mentioned (meth)acrylic acid ester compound C simultaneously with the above-mentioned compound A, and it is preferable to prepare a mixed solution of the above-mentioned compound A and the above-mentioned (meth)acrylic acid ester compound B, and then add and mix the photoradical polymerization initiator separately.

[0053] [Cured Product] The cured product of the present invention is a cured product obtained from the curable composition of the present invention, and is a cured product obtained from the curable composition of the present invention. ａ ~R ｈ and a cured product obtained by curing a curable composition containing the compound A and the (meth)acrylic acid ester compound B, wherein at least one of the groups is a (meth)acryloylthioxy group. The cured product of the present invention is obtained by proceeding with a polymerization reaction of a monomer containing the compound A and the (meth)acrylic acid ester compound B, and curing the monomer. The cured product of the present invention may contain unreacted monomers (e.g., the compound A, the (meth)acrylic acid ester compound B), etc. As described above, the cured product of the present invention can exhibit a high refractive index.

[0054] The refractive index of the cured product of the present invention can be evaluated using the refractive index (nD) at 25°C and a wavelength of 589 nm (also referred to simply as the "refractive index nD of the cured product" in the present invention). The refractive index nD of the cured product of the present invention is preferably 1.550 or greater, more preferably 1.600 or greater, and even more preferably 1.650 or greater. There is no particular upper limit to the refractive index nD of the cured product of the present invention, and a practical upper limit is 1.800 or less. The refractive index nD of the cured product is a value measured using an Abbe refractometer (e.g., manufactured by Atago Co., Ltd., product name: Multi-wavelength Abbe refractometer DR-M2 or DR-M4). Specifically, a measurement sample (cured product) can be prepared and measured according to the description of the Examples below. When forming the cured product, a heating step may be employed instead of the ultraviolet irradiation step described in the Examples below, or both a heating step and an ultraviolet irradiation step may be employed. In addition, JIS B 7090:1999 Optics and optical instruments - Reference wavelengths (ISO 7944:1998 Optics and optical instruments - Reference wavelengths) can be referred to as appropriate.

[0055] The transmittance of the cured product of the present invention is preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more over the entire visible light wavelength range of 360 to 830 nm. The upper limit of the transmittance of the cured product of the present invention is not particularly limited, but practically 99% or less. The transmittance of the cured product is the value of external transmittance, including surface reflection, measured for a 150 μm thick cured product using an ultraviolet-visible spectrophotometer (for example, UV-2600 (trade name), manufactured by Shimadzu Corporation).

[0056] The shape and thickness of the cured product of the present invention can be appropriately adjusted depending on the shape to which the cured product of the present invention is to be applied. For example, the thickness of the cured product of the present invention can be preferably determined in accordance with the description of the thickness of the thin film of the cured product in the OLED display element of the present invention described below. In other words, the cured product of the present invention is preferably a thin film.

[0057] [Method for producing a cured product] The cured product of the present invention can be produced by a method including a step of photocuring the curable composition described above. When photocuring, it is preferable to include the above-mentioned photoradical polymerization initiator in the curable composition. Regarding the photocuring conditions, the description regarding the photocuring conditions for an organic electroluminescence display element described below can be preferably applied. In the method for producing a cured product of the present invention, it is preferable to form a coating film (preferably an inkjet coating film) using the curable composition of the present invention, and then photocuring the film to obtain a cured product.

[0058] [Uses of Cured Product] The cured product of the present invention can be used for a variety of purposes, and because it exhibits a high refractive index, it can be preferably used as an optical material. In particular, because the curable composition of the present invention used to obtain the cured product of the present invention exhibits low viscosity and excellent thin film printability, it is possible to prepare a thin film cured product having a thickness of about several micrometers to several tens of micrometers using a technique using an inkjet device, etc. Therefore, it can be preferably used as a thin film sealing film for sealing OLED element parts, etc.

[0059] [Organic Electroluminescent Display Element (OLED Display Element)] The OLED display element of the present invention comprises a sealing film made of the cured product of the present invention, a barrier layer, and an OLED element portion. In the OLED display element of the present invention, the sealing film made of the cured product of the present invention functions as a thin-film encapsulant in the OLED display element. In the diffractive optical element of the present invention, the thickness of the sealing film is preferably 1 to 100 μm, more preferably 2 to 50 μm. The barrier layer in the OLED display element of the present invention can be any barrier layer commonly used in OLED display elements, without particular limitation, to suppress deterioration of the OLED element portion due to water vapor, oxygen gas, etc. It may be made of either an organic or inorganic material, and may be a single layer or multiple layers, or a layer made of a composite of an organic material and an inorganic material. Since the sealing film made of the cured product of the present invention exhibits a high refractive index, a barrier layer with a high refractive index is used to suppress interfacial reflection at the interface with the barrier layer. A high refractive index barrier layer means that the refractive index (nD) at a wavelength of 589 nm is 1.70 to 2.00. The refractive index (nD) at a wavelength of 589 nm is a value measured by the same method as the refractive index nD of the cured product of the present invention described above. In the organic light-emitting display element of the present invention, it is preferable to adjust the difference between the refractive index (nD) at a wavelength of 589 nm of the sealing layer made of the cured product of the present invention and the refractive index (nD) at a wavelength of 589 nm of the barrier layer to, for example, 0.30 or less. The OLED display unit in the OLED display element of the present invention refers to a laminate sandwiched between a cathode and an anode and responsible for the light-emitting mechanism, and typically has a structure in which a cathode (metal electrode), an electron injection layer, an electron transport layer, a hole blocking layer, a light-emitting layer, a hole transport layer, a hole injection layer, and an anode (transparent electrode) are laminated. Note that the OLED display unit is not limited to this structure, and any OLED display unit commonly used in OLED display elements can be used without particular limitation. In the OLED display element of the present invention, the arrangement and configuration of the sealing film made of the cured product of the present invention, the barrier layer, and the OLED element unit, as well as the size and shape of each component, are also not particularly limited.The arrangement and configuration of the thin-film encapsulant, barrier layer, and OLED element portion, as well as the size and shape of each component, commonly used in OLED display elements, can be applied. Specific examples include an OLED display element comprising an OLED element portion, an inorganic barrier layer, a sealing film made of the cured product of the present invention, and an inorganic barrier layer laminated in this order, and a touch sensor is disposed on the inorganic barrier layer side of the surface of this OLED display element for use. The sealing film made of the cured product of the present invention and the inorganic barrier layer may be repeatedly laminated. Regarding the laminate configuration of the OLED display element and components other than the sealing film made of the cured product of the present invention, such as the inorganic barrier layer, see, for example, the corresponding descriptions in paragraphs

[0060] to

[0074] of JP-A No. 2024-500396, which relate to organic electronic devices, and can be applied to the present invention.

[0060] [Method for sealing organic light-emitting element] The form of the OLED element is not particularly limited as long as the cured product obtained from the curable composition of the present invention functions as a sealing film. The method for sealing the OLED element may include sealing the OLED element with a cured product obtained from the curable composition of the present invention. For example, a method is preferred in which the curable composition of the present invention is formed into a film by a method using an inkjet device (inkjet method) and cured to seal the OLED element. Thin film sealing techniques using the inkjet method can be applied to the present invention by referring to, for example, the descriptions in JP-A-2024-500396 and JP-A-2023-156307.

[0061] The photocuring conditions are preferably as follows: The light used for irradiation to cure the curable composition is preferably ultraviolet light or visible light, and more preferably ultraviolet light. For example, a metal halide lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a germicidal lamp, a xenon lamp, an LED (Light Emitting Diode) light source lamp, or the like is preferably used. The illuminance of the ultraviolet light used for irradiation to cure the curable composition is 1 to 100 mW / cm. ２ is preferred, and 1 to 75 mW / cm ２ More preferably, 5 to 50 mW / cm２ It is more preferable that the ultraviolet light be irradiated multiple times with different illuminances. The exposure dose of the ultraviolet light is 0.4 to 10 J / cm. ２ is preferred, and 0.5 to 5 J / cm ２ More preferably, 1 to 3 J / cm ２ The atmosphere during light irradiation is preferably air or an inert gas-substituted atmosphere, and more preferably an atmosphere in which air has been substituted with nitrogen until the oxygen concentration becomes 1% or less.

[0062] The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In the following, room temperature means 25°C unless otherwise specified. All steps from preparation of the curable composition to production of the cured product or evaluation tests were carried out in an environment using yellow light as illumination.

[0063] [Synthesis Example] Compound A and a comparative compound were synthesized as follows.

[0064] [Synthesis Example 1: Synthesis of Compound (A-4)]

[0065] While mixing 5.00 g (26.0 mmol) of 1,6-naphthalenedithiol and 60 mL of N,N-dimethylacetamide (DMAc), the mixture was cooled to an internal temperature (liquid temperature) of 0°C. 6.93 g (54.6 mmol) of 3-chloropropionyl chloride (3CPC) was added dropwise so that the liquid temperature did not exceed 7°C, and the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, the mixture was cooled to 0°C and triethylamine (Et ３11.05 g (109.2 mmol) of ethyl acetate (N) was added dropwise so that the liquid temperature did not exceed 7°C, and then the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, 150 mL of ethyl acetate and 150 mL of 1N hydrochloric acid were added, followed by washing and separation. Next, 80 mL of a 5% aqueous solution of sodium bicarbonate was added, followed by stirring, washing and separation. An oily composition was obtained by dehydration with magnesium sulfate, filtration, and concentration, and then purified by column chromatography using hexane and ethyl acetate to obtain 6.3 g of compound (A-4). Yield: 81%. Compound (A-4) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 2H), 6.3-6.6 (m, 4H), 7.6-7.7 (m, 2H), 7.78 (d, 1H), 7.96 (d, 1H), 8.05 (s, 1H), 8.21 (d, 1H)

[0066] Synthesis Example 2: Synthesis of Compound (A-8) Compound (A-8) described below was synthesized in the same manner as in Synthesis Example 1, except that 1,6-naphthalenedithiol was replaced with 2,7-naphthalenedithiol. Yield: 80%. Compound (A-8) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 2H), 6.3-6.6 (m, 4H), 7.5-7.6 (m, 2H), 7.92 (d, 2H), 7.98 (s, 2H)

[0067] [Synthesis Example 3: Synthesis of compound (A-9)]

[0068] While mixing 5.00 g (22.3 mmol) of 1,3,6-naphthalene trithiol and 75 mL of N,N-dimethylacetamide (DMAc), the mixture was cooled to an internal temperature (liquid temperature) of 0°C. 8.77 g (69.1 mmol) of 3-chloropropionyl chloride (3CPC) was added dropwise so that the liquid temperature did not exceed 7°C, and the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, the mixture was cooled to 0°C and triethylamine (Et ３13.98 g (138.2 mmol) of ethyl acetate (N) was added dropwise so that the liquid temperature did not exceed 7°C, and then the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, 150 mL of ethyl acetate and 150 mL of 1N hydrochloric acid were added, followed by washing and separation. Next, 80 mL of a 5% aqueous solution of sodium bicarbonate was added, followed by stirring, washing and separation. An oily composition was obtained by dehydration with magnesium sulfate, filtration, and concentration, and then purified by column chromatography using hexane and ethyl acetate to obtain 6.2 g of compound (A-9). Yield: 72%. Compound (A-9) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 3H), 6.3-6.6 (m, 6H), 7.6-7.7 (m, 1H), 7.80 (s, 1H), 8.01 (s, 1H), 8.07 (s, 1H), 8.20 (d, 1H)

[0069] Synthesis Example 4: Synthesis of Compounds (A-38) and (A-46)

[0070] <Synthesis of Compounds (A-38A) and (A-46A)> Under a nitrogen atmosphere, 10 g (52.0 mmol) of 1,6-naphthalenedithiol, 4.68 g (52.0 mmol) of dimethyl carbonate (DMC), and 30 mL of N,N-dimethylacetamide (DMAc) were mixed, and then 8.62 g (52.0 mmol) of potassium carbonate was added and the mixture was heated to an internal temperature (liquid temperature) of 50°C. After stirring for 3 hours, 100 mL of ethyl acetate and 100 mL of 2N hydrochloric acid were added, followed by washing and separation. Next, 100 mL of 2N hydrochloric acid was added again, followed by washing and separation. 100 mL of a 15% aqueous sodium chloride solution was added, followed by stirring, followed by washing and separation. After dehydration with magnesium sulfate, filtration, and concentration, 14 g of an oily composition containing Compound (A-38A) and Compound (A-46A) was obtained. Yield: 90%.

[0071] <Synthesis of Compounds (A-38) and (A-46)> 14.0 g (67.8 mmol) of a mixture containing the above-mentioned compound (A-38A) and compound (A-46A) and 3 mL of N,N-dimethylacetamide (DMAc) were mixed and cooled to an internal temperature (liquid temperature) of 0°C. 9.91 g (78.0 mmol) of 3-chloropropionyl chloride (3CPC) was added dropwise so that the liquid temperature did not exceed 7°C, and then the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, the mixture was cooled to 0°C, and triethylamine (Et ３ 16.5 g (163 mmol) of ethyl acetate (N) was added dropwise so that the liquid temperature did not exceed 7°C, and then the mixture was heated so that the internal temperature (liquid temperature) reached 25°C. After stirring for 1 hour, 56 mL of ethyl acetate and 98 mL of 1N hydrochloric acid were added, followed by washing and separation. Next, 56 mL of 1N hydrochloric acid was added again, followed by washing and separation. Next, 56 mL of a 5% aqueous solution of sodium bicarbonate was added, followed by stirring, followed by washing and separation. After dehydration with magnesium sulfate, filtration, and concentration, the mixture was purified by column chromatography, and compound (A-38) and compound (A-46) were isolated, respectively. Compound (A-38): Yield 20%, Compound (A-46): Yield 25%. Compound (A-38) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 2.58 (s, 3H), 5.8-5.9 (m, 1H), 6.3-6.6 (m, 2H), 7.4-7.6 (m, 2H), 7.6-7.7 (m, 2H), 7.85 (d, 1H), 8.03 (d, 1H) Compound (A-46) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 2.58 (s, 3H), 5.8-5.9 (m, 1H), 6.3-6.6 (m, 2H), 7.4-7.6 (m, 3H), 7.6-7.7 (m, 1H), 7.98 (s, 1H), 8.33 (d, 1H)

[0072] All of the compounds obtained in the above synthesis examples were crystalline.

[0073] <Synthesis of Comparative Compounds> [Synthesis of Comparative Compound 1: Synthesis of Comparative Compound (C-1)]

[0074] Comparative compound (C-1) was synthesized (yield 77%) in the same manner as in Synthesis Example 1, except that 1,6-naphthalenedithiol was replaced with 2,6-naphthalenedithiol. １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 2H), 6.3-6.6 (m, 4H), 7.53 (d, 2H), 7.88 (d, 2H), 8.01 (s, 2H)

[0075] [Synthesis of Comparative Compound 2: Synthesis of PTPBA and BADS] The comparative compounds PTPBA and BADS described below were synthesized with reference to the synthesis of PTPBA and BADS described in the Examples section of JP-A No. 2021-523281.

[0076] The compound (A-30) used was 16DMNDSH (trade name) manufactured by Sugai Chemical Industry Co., Ltd. The naphthothiol raw material was also obtained from Sugai Chemical Industry Co., Ltd.

[0077] [Preparation of Curable Compositions] Compound A and / or a comparative compound as the main monomer and (meth)acrylic acid ester compound B as another monomer were mixed to obtain the compositions shown in Tables 1-1 and 1-2 below (collectively referred to as "Table 1"), dissolved in ethyl acetate, and then concentrated at 60°C under a reduced pressure of 40 hPa until the ethyl acetate was completely removed. A photoradical polymerization initiator (referred to as "photopolymerization initiator" in Table 1) and BYK-302 (trade name, silicone surface conditioner, manufactured by BYK Japan) as a leveling agent were added to the resulting concentrate, and the mixture was stirred to homogenize while heating to 60°C to prepare curable compositions. Curable Compositions Nos. 101 to 116 are curable compositions of the present invention, and Curable Composition No. c11 is a curable composition for comparison.

[0078] The refractive index, thin film printability, and viscosity of the curable compositions were evaluated as follows. The results are shown in Table 1.

[0079] [Preparation of Cured Product] The curable composition prepared above was sandwiched between hydrophobized glass plates so that the film thickness of the cured product would be 150 μm, and the cured product was irradiated with nitrogen (N ) using a UV irradiation device (EXECURE 3000 (trade name), manufactured by HOYA CANDEO OPTRONICS) to an oxygen concentration of 1% or less. ２ ) In a substituted atmosphere, the cumulative light dose was 1.2 J / cm ２ , illuminance 5mW / cm ２ After irradiating with UV (ultraviolet rays) under the conditions of

[0049] , the film was peeled off from the glass plate to prepare a cured product. The transmittance values ​​of the cured products of the curable compositions Nos. 101 to 116 prepared above, each having a film thickness of 150 μm, measured by the above-described measurement method, were all 85% or higher over the entire visible light wavelength range of 360 to 830 nm.

[0080] [Evaluation 1: Refractive Index Measurement] Using the cured products prepared under the above conditions, the refractive index at a wavelength of 589 nm (refractive index nD of the cured product) was measured at 25°C using a multi-wavelength Abbe refractometer DR-M2 or DR-M4 (trade name, manufactured by Atago Co., Ltd.), and evaluated according to the following criteria: - Evaluation criteria for refractive index nD of cured product - A: 1.650≦nD B: 1.600≦nD<1.650 C: 1.550≦nD<1.600 D: nD<1.550

[0081] [Evaluation 2: Thin Film Printability] The curable composition prepared above was introduced into an inkjet cartridge DMC-11610 (trade name, manufactured by Fujifilm Dimatix Corporation). This inkjet cartridge was set in an inkjet device Material Printer DMP-2831 (trade name, manufactured by Fujifilm Dimatix Corporation). After adjusting the discharge state, the composition was applied to a SiN substrate with a coating thickness of 5 μm and a size of 8 mm length x 22 mm width. The resulting coating film was left at room temperature (25°C) for 1 minute, and then exposed to nitrogen (N ) using a UV irradiation device (EXECURE 3000 (trade name), manufactured by HOYA CANDEO OPTRONICS Corporation) to an oxygen concentration of 1% or less. ２ ) In a substituted atmosphere, the cumulative light dose was 1.2 J / cm ２ , illuminance 5mW / cm ２The cured coating film (sample) was observed under a microscope at a magnification of 20x over an area of ​​6mm length x 18mm width to check for spot defects in the sample, and the thin film printability was evaluated according to the following criteria. The spot defects in the sample are microcrystals generated during the inkjet ejection process, and are presumed to be due to the high crystallinity of Compound A and the comparative compound. - Evaluation criteria for thin film printability - A: No spot defects were observed in the sample. B: One spot defect was observed in the sample. C: Two to three spot defects were observed in the sample. D: Four to five spot defects were observed in the sample. E: Six to eight spot defects were observed in the sample. F: Nine to eleven spot defects were observed in the sample. G: 12 or more spot defects were observed in the sample.

[0082] [Evaluation 3: Viscosity Measurement] Using a rheometer (product name: HAAKE RheoStress 6000, manufactured by Thermo Fisher Scientific), the curable composition prepared above was subjected to viscosity measurement at a shear rate of 10 s －１ , the viscosity η at 25°C to 50°C was measured, and the lowest viscosity η ｍｉｎ The viscosity was evaluated according to the following criteria: 1 cP is 1 mPa·s. Viscosity evaluation criteria: A: η ｍｉｎ ≦20cP B:20cP<η ｍｉｎ ≦40cP C:40cP<η ｍｉｎ

[0083]

[0084]

[0085] The wt% blending amount of each component listed in the Component column means % by mass. Furthermore, the component ratio listed in the Main Monomer column means the content ratio of each compound constituting the main monomer, and wt% means % by mass. If the main monomer is a mixture of two or more compounds, the content ratio of each compound is listed in the order of the compounds listed in the Type column. For example, in No. 105, the main monomer is composed of 33.4 wt% A-4, 33.3 wt% A-8, and 33.3 wt% A-9. Note that a "-" in the Main Monomer component ratio column indicates that there is only one main monomer and the content ratio of the mixture is not listed.

[0086] The components in the table are as follows: Main monomer: Compound A or a comparative compound shown below. In the structural formulas below, the point group is also shown below the number of each compound.

[0087] (Compound A)

[0088] (Comparative Compound)

[0089] Comparative compound (C-1) has a point group C ｓ But C ２ｖ The comparative compounds BADS and PTPBA do not contain a naphthalene ring and are not compounds represented by general formula (1), and therefore are not Compound A as defined in the present invention. The comparative compound PTPBA (p-thiophenylbenzyl acrylate) corresponds to the acrylate of formula I described in JP-T-2021-523281, and the comparative compound BADS (4,4'-bis[(acryloyloxyethylthio)diphenyl sulfide]) corresponds to the polyfunctional (meth)acrylate of formula VII described in JP-T-2021-523281.

[0090] (Other Monomers) 1,12-DDDMA: 1,12-dodecanediol dimethacrylate

[0091] (Leveling agent) BYK-302: Trade name, manufactured by BYK Japan, silicone-based surface conditioner

[0092] (Photopolymerization initiator) IrgTPO: Irgacure TPO (trade name, manufactured by BASF Japan Ltd., available as Omnirad TPO H (trade name, manufactured by IGM Resins B.V.)), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide

[0093] The results in Table 1 reveal the following. Comparative curable composition No. c11 is not a curable composition of the present invention in that it contains comparative compounds BADS and PTPBA, ​​which are not compound A. This comparative curable composition No. c11 had 12 or more point-like defects in the cured thin film, exhibiting poor thin-film printability. Furthermore, the minimum viscosity at 20 to 50°C was high, exceeding 40 cP, failing to achieve a low viscosity of the composition. In contrast, curable compositions Nos. 101 to 116 of the present invention had low minimum viscosities of the composition (liquid) at 20 to 50°C, of ​​40 cP or less, and the resulting cured products all had high and excellent refractive indices nD of 1.550 or more, and also had excellent thin-film printability. Furthermore, curable composition Nos. 101 to 116 of the present invention, which contained the same blending ratio of compound A and (meth)acrylic acid ester compound B, exhibited excellent thin-film printability. Considering the curable compositions Nos. 101 to 108 and 112 to 116, curable compositions Nos. 103 to 108 and 112 to 115 containing two or more compounds A showed better thin-film printability, and curable compositions Nos. 105 to 108, 112 and 113 containing three or more compounds A showed even better thin-film printability. Furthermore, when comparing curable compositions Nos. 103, 104, 114 and 115 containing two compounds A and curable compositions Nos. 105 to 108, 112 and 113 containing three or more compounds A, all point groups of compound A were C ｓ or when the content of each compound A relative to 100 mass% of the total amount of compound A was 10 mass% or more, particularly excellent thin-film printability was exhibited (see Curable Compositions Nos. 103 and 114 compared to Curable Compositions Nos. 103, 104, 114, and 115, and Curable Compositions Nos. 106 to 108 and 112 compared to Curable Compositions Nos. 105 to 108, 112, and 113, respectively).

[0094] While the present invention has been described in connection with embodiments thereof, we do not intend to limit our invention to any of the details of the description unless otherwise specified, and believe that the claims should be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

[0095] This application claims priority based on Japanese Patent Application No. 2024-105756, filed on June 28, 2024, the contents of which are incorporated herein by reference as part of the present specification.

Claims

1. A curable composition for use in sealing an organic electroluminescence element, wherein the curable composition is represented by the following general formula (1) and the point group is C ｓ or C ２ｖ and a (meth)acrylic acid ester compound having a molecular weight of 500 or less, wherein at least one of the compounds A is ａ ~R ｈ A curable composition, wherein at least one of the above is a compound having a (meth)acryloylthioxy group. In the above formula, R ａ ~R ｈ represents a hydrogen atom, an alkylsulfanyl group having 1 to 10 carbon atoms, or a (meth)acryloylthioxy group.

2. The curable composition according to claim 1, comprising two or more types of compound A.

3. The curable composition according to claim 2, which contains three or more types of compound A.

4. All point groups of the compound A are C ｓ The curable composition of claim 2, wherein 5. The curable composition according to claim 2, wherein the content of each compound A is 10% by mass or more relative to a total of 100% by mass of the compounds A.

6. The curable composition according to claim 1, wherein the minimum viscosity within a temperature range of 25 to 50°C is 20 cP or less, and the refractive index of a cured product obtained from the curable composition at 25°C and a wavelength of 589 nm is 1.550 or more.

7. A cured product obtained from the curable composition according to any one of claims 1 to 6.

8. An organic electroluminescence display device comprising a sealing film made of the cured product according to claim 7, a barrier layer, and an organic electroluminescence device section.

9. A method for sealing an organic electroluminescence element part, comprising sealing the organic electroluminescence element part with a cured product obtained from the curable composition according to any one of claims 1 to 6.

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