TWI898129B - Composition, cured body, and organic el display device - Google Patents

Abstract

A composition containing a polymerizable compound, inorganic microparticles, and a photopolymerization initiator, wherein the inorganic microparticle content of the composition is at least 30% by volume, and the cured depth upon irradiation with light having a wavelength of 365 nm at an irradiation dose of 600 mJ/cm ², and subsequent standing at 80°C for 30 minutes, is at least 100 µm.

Description

Composition, hardened body and organic electroluminescent display device

The present invention relates to a composition, a hardened body and an organic electroluminescent display device.

In recent years, research on organic optical devices using organic thin film elements such as organic electroluminescent (organic EL) display elements and organic thin film solar cell elements has been progressing.

Organic EL displays consist of a thin-film structure with an organic luminescent material layer sandwiched between a pair of facing electrodes. Electrons are injected into this layer from one electrode, while holes are injected from the other. The electrons and holes combine within the layer, generating spontaneous light. Compared to liquid crystal displays (LCDs), which require backlights, organic EL displays offer improved visibility, thinner dimensions, and the ability to be driven by low-voltage DC power.

However, if the organic luminescent material layer and electrodes of such organic EL display devices are exposed to the outside world, their luminescence properties will be significantly degraded and their lifespan will be shortened. Therefore, to improve the stability and durability of organic EL display devices, organic EL display devices require sealing technology to protect the organic luminescent material layer and electrodes from moisture and oxygen in the atmosphere.

For example, Patent Document 1 discloses a method for sealing a top-emitting organic electroluminescent display device by filling a space between organic electroluminescent display device substrates with a photocurable sealant and then irradiating the space with light. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-357973

(The problem to be solved)

In recent years, with the increasing size of organic electroluminescent display devices (especially organic electroluminescent televisions), there has been a demand for sealing materials that can achieve higher moisture resistance and long-term reliability.

In view of the above circumstances, the present invention aims to provide a composition capable of forming a sealant with excellent moisture resistance and long-term reliability. Furthermore, the present invention aims to provide a cured product of the composition and an organic electroluminescent display device having a seal structure formed using the composition. (Means of Solution)

The present invention relates, for example, to the following <1> to <18>. <1> A composition comprising a polymerizable compound, inorganic fine particles, and a photopolymerization initiator, wherein the content of the inorganic fine particles is 30% by volume or more, and when irradiated with light having a wavelength of 365 nm and an irradiation dose of 600 mJ/ ^cm2 and left to stand at 80°C for 30 minutes, the cured depth is 100 μm or more. <2> The composition according to <1>, wherein the polymerizable compound has at least one polymerizable group selected from the group consisting of a carbon-carbon double bond and a cyclic ether. <3> The composition according to <1> or <2>, wherein the inorganic fine particles have a refractive index _n2 such that the absolute value of the difference (| _n1 - _n2 |) between the refractive index n1 of the polymer of the polymerizable compound and the refractive index _n2 is 0.5 or less. <4> The composition of any one of <1> to <3>, wherein the refractive index _n2 of the inorganic fine particles is 1.4 or greater. <5> The composition of any one of <1> to <4>, wherein the average circularity of the inorganic fine particles is 0.7 or greater and 1.0 or less. <6> The composition of any one of <1> to <5>, wherein the inorganic fine particles contain at least one selected from the group consisting of spherical silica and spherical alumina. <7> The composition of any one of <1> to <6>, wherein the sum ( _T0 + _R0 ) of the total light transmittance _T0 (%) and the total light reflectance _R0 (%) at a thickness of 100 μm is 50% or greater. <8> The composition of any one of <1> to <7>, wherein the photopolymerization initiator contains a compound represented by the following formula (1): [Chemical 1] In formula (1), R ¹ represents a hydrogen atom, an alkyl group which may be substituted, or an aryl group which may be substituted, and X ^- represents a monovalent anion. A plurality of R ¹ groups may be the same or different. <9> The composition according to any one of <1> to <8> further comprises a photosensitizer represented by the following formula (2): [Chemical 2] In formula (2), R ² represents an alkyl group which may be substituted; multiple R ² groups may be the same or different. <10> The composition according to any one of <1> to <9> is used to form a cured product having a moisture permeability of 100 g/(m ² ･24 hours) or less per 100 μm thickness, as measured at a temperature of 85°C and a relative humidity of 85% in accordance with JIS Z0208. <11> The composition according to any one of <1> to <10> is used to form a cured product having a water absorption of 3% or less per 24 hours at a temperature of 85°C and a relative humidity of 85%. <12> The composition according to any one of <1> to <11> is a sealant for an organic electroluminescent display device. <13> The composition according to any one of <1> to <12>, which is a sealant for forming a dam using a dam-filling method. <14> A composition comprising: a polymerizable compound; inorganic fine particles having a refractive index _n2 such that the absolute value of the difference between the refractive index _n1 of a polymer of the polymerizable compound (| _n1 - _n2 |) is 0.5 or less; and a photopolymerization initiator, wherein the content of the inorganic fine particles is 30% by volume or more, the content of the photopolymerization initiator is 0.3 parts by mass or more per 100 parts by mass of the polymerizable compound, and the average circularity of the inorganic fine particles is 0.7 or more and 1.0 or less. <15> A cured article, which is the cured article of the composition according to any one of <1> to <14>. <16> An organic electroluminescent display device comprising: an organic electroluminescent display element; and a sealing structure comprising a dam and a filler for sealing the organic electroluminescent display element, wherein the dam comprises the hardened body described in <15>. <17> The organic electroluminescent display device described in <16> is an organic electroluminescent television. (Effects of the Invention)

The present invention provides a composition capable of forming a sealant with excellent moisture resistance and long-term reliability. Furthermore, the present invention provides an organic electroluminescent display device having a cured product of the composition and a seal structure formed using the composition.

The following is a detailed description of the preferred embodiments of the present invention.

The composition of this embodiment comprises a polymerizable compound, inorganic particles, and a photopolymerization initiator. The inorganic particles comprise at least 30% by volume. When irradiated with light at a wavelength of 365 nm and a dose of 600 mJ/ ^cm² at 80°C for 30 minutes, the cured composition exhibits a depth of at least 100 μm.

The composition of this embodiment can form a sealant with excellent moisture resistance and long-term reliability. Therefore, the composition of this embodiment is ideally suited for use as a sealant (preferably a sealant for organic electroluminescent display devices, and particularly preferably a sealant for organic electroluminescent televisions). Furthermore, the composition of this embodiment is particularly suitable for use as a dam-forming sealant for forming dams in a dam-and-fill method (a sealing structure composed of a dam and a filler).

The reason why the composition according to this embodiment can achieve the above-mentioned effect is not fixed, but it is believed to be as follows. The composition according to this embodiment forms a hardened body containing a large amount of inorganic particles with low moisture permeability compared to resin materials. In addition, if the content of inorganic particles in the composition is high, light irradiation will be hindered by the inorganic particles, and the amount of unreacted monomers (unreacted polymerizable compounds) in the hardened body tends to increase. However, since this embodiment has the above-mentioned curing depth, light irradiation during sealing can sufficiently reduce unreacted monomers, which can suppress the reduction in moisture resistance and reliability caused by unreacted monomers. In other words, it is believed that this embodiment can achieve excellent moisture resistance and long-term reliability by making a composition that is sufficiently mixed with inorganic particles and has a predetermined curing depth.

In this embodiment, the polymerizable compound can be referred to as a compound having a polymerizable group. The polymerizable compound can be used alone or in combination of two or more.

The polymerizable compound preferably has at least one polymerizable group selected from the group consisting of a carbon-carbon double bond and a cyclic ether.

The carbon-carbon double bond can be any free-radical or cationic-polymerizable carbon-carbon double bond. Examples of compounds having carbon-carbon double bonds include compounds having polymerizable groups such as (meth)acryloyl, vinyl, allyl, vinyl ether, and vinyl ester groups. Among these, compounds having (meth)acryloyl groups ((meth)acrylate compounds) are preferred.

The (meth)acrylate compound includes, for example, a monofunctional (meth)acrylate having one (meth)acryloyl group and a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups.

Monofunctional (meth)acrylates, such as alkyl (meth)acrylates (such as ethyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, etc.), benzyl (meth)acrylate, ethoxylated o-phenylphenol (meth)acrylate, etc.

Polyfunctional (meth)acrylates include, for example, alkanediol di(meth)acrylates (such as 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, and 1,12-dodecanediol di(meth)acrylate), tricyclodecanedimethanol di(meth)acrylate, and the like.

The cyclic ether may be any cyclic ether that is cationic polymerizable. Examples of compounds having cyclic ethers include epoxy compounds and oxycyclobutane compounds.

Epoxy compounds include, for example, alicyclic compounds having an epoxy group (alicyclic epoxy compounds), aromatic compounds having an epoxy group (aromatic epoxy compounds), and non-epoxy compounds having an epoxy group (non-epoxy epoxy compounds). More than one of these compounds may be used.

Alicyclic epoxy compounds include, for example, compounds obtained by epoxidizing a compound having at least one cycloalkene ring (e.g., cyclohexene, cyclopentene, or pinene) with a suitable oxidizing agent such as hydrogen peroxide or peracid, or derivatives thereof. Alicyclic epoxy compounds also include, for example, hydroepoxides obtained by hydrogenating aromatic epoxy compounds (e.g., bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, etc.).

Examples of aliphatic epoxy compounds include: 3',4'-epoxyepoxyhexylmethyl 3,4-epoxyepoxyhexanecarboxylate, 3,4-epoxyepoxyhexylalkyl (meth)acrylates (e.g., 3,4-epoxyepoxyhexylmethyl (meth)acrylate), (3,3',4,4'-dicyclohexyl)biscyclohexyl, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, and the like.

Among the alicyclic epoxy compounds, those having a 1,2-epoxyhexane structure are preferred. Among the alicyclic epoxy compounds having a 1,2-epoxyhexane structure, the compound represented by the following formula (A1-1) is preferred. [Chemical 3]

In formula (A1-1), X represents a single bond or a linking group (a divalent group having one or more atoms).

The linking group is preferably a divalent alkyl group, a carbonyl group, an ether bond, an ester bond, a carbonate group, an amide bond, or a group formed by linking a plurality of these groups.

X is preferably a linking group. The linking group is preferably a group having an ester bond. Examples of compounds having a group having an ester bond as a linking group include: 3',4'-epoxyhexylmethyl 3,4-epoxyhexanecarboxylate.

Regarding the molecular weight of the aliphatic epoxy compound, from the perspective of improving the moisture resistance of the cured product and the storage stability of the composition, it is preferably 1000 or less, more preferably 450 or less, even more preferably 400 or less, even more preferably 300 or less, and particularly preferably 100-280. Specifically, the molecular weight of the aliphatic epoxy compound may be, for example, 100-1000, 100-450, 100-400, 100-300, or 100-280.

When the alicyclic epoxy compound has a molecular weight distribution, the number average molecular weight of the alicyclic epoxy compound is preferably within the above range. In this specification, the number average molecular weight represents the polystyrene-equivalent value measured by gel permeation chromatography (GPC) under the following measurement conditions. Solvent (mobile phase): THF Degassing device: ERC-3310, manufactured by ERMA Pump: PU-980, manufactured by JASCO Corporation Flow rate: 1.0 ml/min Autosampler: AS-8020, manufactured by Tosoh Corporation Column oven: L-5030, manufactured by Hitachi, Ltd. Set temperature: 40°C Column configuration: 2 Tosoh TSK guardcolumn MP (×L) 6.0 mm ID × 4.0 cm, and 2 Tosoh TSK-GELMULTIPORE HXL-M 7.8 mm ID × 30.0 cm, for a total of 4 columns Detector: RI, L-3350, manufactured by Hitachi, Ltd. Data processing system: SIC480 data station

Aromatic epoxy compounds may be used in the form of monomers, oligomers, or polymers. Examples include brominated bisphenol A type epoxy resins such as tetrabromobisphenol A diglycidyl ether, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, fluorene type epoxy resins, novolac phenol type epoxy resins, cresol novolac type epoxy resins, phenyl glycidyl ether, and modified products thereof.

The aromatic epoxy compound is preferably an aromatic epoxy compound having a bisphenol structure. Among the aromatic epoxy compounds having a bisphenol structure, the compound represented by the following formula (A2-1) is preferred.

[Chemistry 4]

In formula (A2-1), n represents 0 to 30, and R ²¹ , R ²² , R ²³ and R ²⁴ each independently represent a hydrogen atom or an optionally substituted alkyl group having 1 to 5 carbon atoms. n may be 0.1 or greater.

R ²¹ , R ²² , R ²³ and R ²⁴ are preferably hydrogen atoms or methyl groups. R ²¹ , R ²² , R ²³ and R ²⁴ may be the same or different, and are preferably the same.

The aromatic epoxy compound having a bisphenol structure is preferably at least one selected from the group consisting of bisphenol A epoxy resin and bisphenol F epoxy resin.

Regarding the molecular weight of the aromatic epoxy compound, from the perspective of improving the moisture resistance of the cured product, 100-5000 is ideal, 150-1000 is more preferred, and 200-450 is even more preferred. Specifically, the molecular weight of the aromatic epoxy compound may be, for example, 100-5000, 100-1000, 100-450, 150-5000, 150-1000, 150-450, 200-5000, 200-1000, or 200-450.

When the aromatic epoxy compound has a molecular weight distribution, the number average molecular weight of the aromatic epoxy compound is preferably within the above range. In this specification, the number average molecular weight represents the polystyrene-equivalent value measured by gel permeation chromatography (GPC) under the above-mentioned measurement conditions.

Non-epoxy epoxy compounds include: diglycidyl ethers of alkylene glycols (e.g., ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, etc.), polyglycidyl ethers of polyols (e.g., di- or triglycidyl ethers of glycerol or its epoxy adducts), and diglycidyl ethers of polyalkylene glycols (e.g., diglycidyl ethers of polyethylene glycol or its epoxy adducts, diglycidyl ethers of polypropylene glycol or its epoxy adducts). Examples of the alkylene oxide include ethylene oxide and propylene oxide.

Oxycyclobutane compounds are not particularly limited, and examples thereof include 3-ethyl-3-hydroxymethyloxycyclobutane (manufactured by Toagosei Co., Ltd., trade name ARON OXETANE OXT-101, etc.), 1,4-bis[(3-ethyl-3-oxycyclobutane)methoxymethyl]benzene (such as OXT-121, etc.), 3-ethyl-3-(phenoxymethyl)oxycyclobutane (such as OXT-211, etc.), di(1-ethyl-(3-oxycyclobutane))methyl ether (such as OXT-221, etc.), and 3-ethyl-3-(2-ethylhexyloxymethyl)oxycyclobutane (such as OXT-212, etc.). Oxycyclobutane compounds refer to compounds having one or more oxycyclobutane rings in the molecule.

Polymerizable compounds having both a carbon-carbon double bond and a cyclic ether can also be used. Examples of polymerizable compounds having both a carbon-carbon double bond and a cyclic ether include glycidyl (meth)acrylate, glycidyl (meth)acrylate, 3-ethyloxycyclobutane-3-ylmethyl (meth)acrylate, 4-vinylcyclohexane oxide, and 3-ethyloxycyclobutane-3-ylmethyl vinyl ether.

Examples of photopolymerization initiators include photocationic polymerization initiators, photoradical polymerization initiators, and photoanionic polymerization initiators. When the composition of this embodiment contains a polymerizable compound having a carbon-carbon double bond, the photopolymerization initiator preferably contains a photoradical polymerization initiator. Furthermore, when the composition of this embodiment contains a polymerizable compound having a cyclic ether, the photopolymerization initiator preferably contains a photocationic polymerization initiator.

The photocatalytic polymerization initiator is not particularly limited, and examples thereof include aryl codon salt derivatives (e.g., CYRACURE UVI-6990, CYRACURE UVI-6974 manufactured by Dow Chemical Company, ADEKA OPTOMER SP-150, ADEKA OPTOMER SP-152, ADEKA OPTOMER SP-170, ADEKA OPTOMER SP-172 manufactured by ADEKA, CPI-100P, CPI-101A, CPI-200K, CPI-210S, CPI-310B, CPI-310FG, CPI-400S, LW-S1 manufactured by San-apro, CHIVACURE 1190 manufactured by Double Bond Chemical Company, etc.), aryl iodonium salt derivatives (e.g., Irgacure 250, RHODIA manufactured by Ciba Specialty Chemicals, etc.), and aryl iodonium salt derivatives (e.g., Irgacure 250, RHODIA manufactured by Ciba Specialty Chemicals, etc.). JAPAN Co., Ltd., RP-2074), aromatic hydrocarbon-ion complex derivatives, diazonium salt derivatives, tribasic initiators, and other acid generators such as halides.

Photocatalytic polymerization initiator, for example, an onium salt represented by formula (B-1). [Chemistry 5] In formula (B-1), A represents an element of Group VIA to Group VIIA with an atomic valence of m, m represents 1 to 2, p represents 0 to 3, R represents an organic group bonded to A, and D is a divalent group represented by the following formula (B-1-1): [Chemistry 6] In formula (B-1-1), E represents a divalent group, G represents -O-, -S-, -SO-, _-SO2- , -NH-, -NR'-, -CO-, -COO-, -CONH-, an alkylene group having 1 to 3 carbon atoms, or a phenylene group (R' represents an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms), and a represents 0 to 5. a+1 E and a G may be the same or different. X- ^is a counter ion to the onium ion.

The onium ion of formula (B-1) is not particularly limited, and examples thereof include 4-(phenylthio)phenyldiphenylcopperium, bis[4-(diphenyldihydrothio)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]dihydrothio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)dihydrothio]phenyl}sulfide, 4-(4-benzyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)copperium, 4-(4-benzylphenylthio)phenyldiphenylcopperium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylcopperium, 7-isopropyl-9-oxo- 10-thia-9,10-dihydroanthracen-2-yldiphenylcopperium, 2-[(di-p-tolyl)dihydrothio]thioxanthone, 2-[(diphenyl)dihydrothio]thioxanthone, 4-[4-(4-tert-butylbenzyl)phenylthio]phenyldi-p-tolylcopperium, 4-(4-benzylphenylthio)phenyldiphenylcopperium, 5-(4-methoxyphenyl)thianthrenium, 5-phenylthianthrenium, diphenylbenzylmethylcopperium, 4-hydroxyphenylmethylbenzylcopperium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylcopperium, 4-hydroxyphenylmethylbenzylmethylcopperium, octadecylmethylbenzylmethylcopperium, etc.

R is an organic group bonded to A. R represents, for example, an aryl group having 6 to 30 carbon atoms, a heterocyclic group having 4 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or an alkynyl group having 2 to 30 carbon atoms, which may also have a substituent. The substituent is, for example, at least one selected from the group consisting of an alkyl group, a hydroxyl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxylene group, an amino group, a cyano group, a nitro group, and a halogen group.

The number of R is m+p(m-1)+1, and they may be the same or different. Furthermore, two or more Rs may be bonded to each other directly or through -O-, -S-, -SO-, -SO ₂ -, -NH-, -NR'-, -CO-, -COO-, -CONH-, an alkylene group having 1 to 3 carbon atoms, or a phenylene group to form a ring structure containing the element A. Here, R' is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms.

Examples of the aryl group having 6 to 30 carbon atoms include monocyclic aryl groups such as phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, and condensed polycyclic aromatic groups such as chrysenyl, fused tetraphenyl, benzanthryl, anthraquinolyl, fluorenyl, naphthoquinone and anthraquinone.

The aryl group having 6 to 30 carbon atoms, the heterocyclic group having 4 to 30 carbon atoms, the alkyl group having 1 to 30 carbon atoms, the alkenyl group having 2 to 30 carbon atoms, or the alkynyl group having 2 to 30 carbon atoms may have at least one substituent. Examples of substituents include: linear alkyl groups having 1 to 18 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl; branched alkyl groups having 1 to 18 carbon atoms, such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, and isohexyl; cycloalkyl groups having 3 to 18 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; hydroxyl groups; linear or branched alkoxy groups having 1 to 18 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, decyloxy, and dodecyl; linear or branched alkylcarbonyl groups having 2 to 18 carbon atoms, such as acetyl, propionyl, butyryl, 2-methylpropionyl, heptyl, 2-methylbutyryl, 3-methylbutyryl, octyl, decyl, dodecyl, and octadecyl; arylcarbonyl groups having 7 to 11 carbon atoms, such as benzyl and naphthyl; linear or branched alkoxycarbonyl groups having 2 to 19 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, octyloxycarbonyl, tetradecyloxycarbonyl, and octadecyloxycarbonyl; aryloxycarbonyl groups having 7 to 11 carbon atoms, such as phenoxycarbonyl and naphthyloxycarbonyl; Arylthiocarbonyl groups having 7 to 11 carbon atoms, such as phenylthiocarbonyl and naphthylthiocarbonyl; linear or branched acyloxy groups having 2 to 19 carbon atoms, such as acetyloxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, and octadecylcarbonyloxy; phenylthio, 2-methylphenylthio, 3-methylphenylthio, 4-methylphenylthio, 2-chlorophenylthio, 3-chlorophenylthio, 4-chlorophenylthio, 2-bromophenylthio, 3-bromophenylthio, 4-bromophenylthio, 2-fluorophenylthio, 3-fluorophenylthio, 4-fluorophenylthio, 2-hydroxyphenylthio, 4-hydroxyphenylthio, 2-methoxyphenylthio, 4-methoxyphenylthio, 1-naphthylthio, 2-naphthylthio, 4-[4-(phenylthio)benzoyl]phenylthio, 4-[4-(phenylthio)phenoxy]phenylthio, 4-[4-(phenylthio)phenylthio] arylthio groups having 6 to 20 carbon atoms, such as phenylthio, 4-(phenylthio)phenylthio, 4-benzylphenylthio, 4-benzyl-2-chlorophenylthio, 4-benzyl-3-chlorophenylthio, 4-benzyl-3-methylthiophenylthio, 4-benzyl-2-methylthiophenylthio, 4-(4-methylthiobenzyl)phenylthio, 4-(2-methylthiobenzyl)phenylthio, 4-(p-methylbenzyl)phenylthio, 4-(p-ethylbenzyl)phenylthio, 4-(p-isopropylbenzyl)phenylthio, and 4-(p-tert-butylbenzyl)phenylthio; Straight-chain or branched alkylthio groups having 1 to 18 carbon atoms, such as methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, sec-butylthio, t-butylthio, pentylthio, isopentylthio, neopentylthio, t-pentylthio, octylthio, decylthio, and dodecylthio; aryl groups having 6 to 10 carbon atoms, such as phenyl, tolyl, dimethylphenyl, and naphthyl; thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidinyl, pyrrolyl, indolyl, benzofuranyl, benzothiophenyl, quinolyl, isoquinolyl, quinolinyl, quinazolinyl, carbazolyl, acridinyl, phenanthr ... heterocyclic groups having 4 to 20 carbon atoms, such as benzothiol, thienyl, phenanthroline, phenoxathiinyl, thiazolyl, isothiozyl, dibenzothiophenyl, xanthonyl, thioxanthonyl, and dibenzofuranyl; Aryloxy groups having 6 to 10 carbon atoms, such as phenoxy and naphthyloxy; linear or branched alkylsulfinyl groups having 1 to 18 carbon atoms, such as methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, butylsulfinyl, isobutylsulfinyl, sec-butylsulfinyl, t-butylsulfinyl, pentylsulfinyl, isopentylsulfinyl, neopentylsulfinyl, t-pentylsulfinyl, and octylsulfinyl; arylsulfinyl groups having 6 to 10 carbon atoms, such as phenylsulfinyl, tolylsulfinyl, and naphthylsulfinyl; a linear or branched alkylsulfonyl group having 1 to 18 carbon atoms, such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, t-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, t-pentylsulfonyl, and octylsulfonyl; an arylsulfonyl group having 6 to 10 carbon atoms, such as phenylsulfonyl, tolylsulfonyl (toluenesulfonyl), and naphthylsulfonyl; Formula (B-1-2): [Chemical 7] an alkylene group (Q represents a hydrogen atom or a methyl group, and k represents an integer from 1 to 5); an unsubstituted amino group; an amino group mono- or di-substituted with an alkyl group having 1 to 5 carbon atoms and/or an aryl group having 6 to 10 carbon atoms; a cyano group; a nitro group; halogens such as fluorine, chlorine, bromine, and iodine;

In formula (B-1), p represents the number of repeating units of the [DA ⁺ R _m-1 ] bond, and is preferably an integer from 0 to 3.

The onium ion [A ⁺ ] in formula (B-1) is preferably columbium, iodonium, or selenonium, and representative examples are listed below.

Copper ions include triphenylcopperium, tri-p-tolylcopperium, tri-o-tolylcopperium, tris(4-methoxyphenyl)copperium, 1-naphthyldiphenylcopperium, 2-naphthyldiphenylcopperium, tris(4-fluorophenyl)copperium, tri-1-naphthylcopperium, tri-2-naphthylcopperium, tris(4-hydroxyphenyl)copperium, 4-(phenylthio)phenyldiphenylcopperium, 4-(p-tolylthio)phenyldi-p-tolylcopperium, 4-(4-methoxyphenylthio)phenylbis(4-methoxyphenyl)copperium, 4-(phenylthio)phenylbis(4-fluorophenyl)copperium, 4-(phenylthio)phenyl Bis(4-methoxyphenyl)copperdihydrogensulfonyl)phenyl]sulfide, 4-(phenylthio)phenyldi-p-tolylcopperdihydrogensulfonyl)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]dihydrosulfonyl}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)dihydrosulfonyl]phenyl}sulfide, bis{4-[bis(4-methylphenyl)dihydrosulfonyl]phenyl}sulfide, bis{4-[bis(4-methoxyphenyl)dihydrosulfonyl]phenyl}sulfide, 4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenylthio)phenyl 4-(4-Benzylphenylthio)phenyldiphenylcopperium, 4-(4-Benzylphenylthio)phenylbis(4-fluorophenyl)copperium, 4-(4-Benzylphenylthio)phenyldiphenylcopperium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylcopperium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylcopperium, 2-[(di-p-tolyl)dihydrothio]thioxanthone, 2-[(diphenyl)dihydrothio]thioxanthone Triaryl coroniums such as xanthone, 4-[4-(4-tert-butylbenzyl)phenylthio]phenyl di-p-tolyl coronium, 4-[4-(4-tert-butylbenzyl)phenylthio]phenyl diphenyl coronium, 4-[4-(benzylphenylthio)]phenyl di-p-tolyl coronium, 4-[4-(benzylphenylthio)]phenyl diphenyl coronium, 5-(4-methoxyphenyl)thianthrenium, 5-phenylthianthrenium, 5-tolylthianthrenium, 5-(4-ethoxyphenyl)thianthrenium, and 5-(2,4,6-trimethylphenyl)thianthrenium; Diaryl coroniums such as diphenylbenzylmethyl coronium, diphenyl-4-nitrobenzylmethyl coronium, diphenylbenzyl coronium, and diphenylmethyl coronium; Monoaryl coroniums such as phenylmethylbenzyl coronium, 4-hydroxyphenylmethylbenzyl coronium, 4-methoxyphenylmethylbenzyl coronium, 4-acetylcarbonyloxyphenylmethylbenzyl coronium, 2-naphthylmethylbenzyl coronium, 2-naphthylmethyl (1-ethoxycarbonyl)ethyl coronium, phenylmethylbenzylmethyl coronium, 4-hydroxyphenylmethylbenzylmethyl coronium, 4-methoxyphenylmethylbenzylmethyl coronium, 4-acetylcarbonyloxyphenylmethylbenzylmethyl coronium, 2-naphthylmethylbenzylmethyl coronium, 2-naphthyloctadecylbenzylmethyl coronium, and 9-anthrylmethylbenzylmethyl coronium; Trialkyl coroniums such as dimethyl benzylmethyl coronium, benzylmethyl tetrahydrothiophenium salt, dimethyl benzyl coronium, benzyl tetrahydrothiophenium salt, octadecylmethyl benzylmethyl coronium, etc.

Among the onium ions, at least one type consisting of coronium ions and iodine ions is preferred, with coronium ions being more preferred. The coronium ion is preferably triphenylcoronium, tri-p-tolylcoronium, 4-(phenylthio)phenyldiphenylcoronium, bis[4-(diphenyldihydrothio)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]dihydrothio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)dihydrothio]phenyl}sulfide, 4-(4-benzyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)coronium, 4-(4-benzylphenylthio)phenyldiphenylcoronium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylcoronium, 7-isopropyl-9-oxo-10- Preferred are at least one of 9,10-dihydroanthracen-2-yldiphenylcathionium, 2-[(di-p-tolyl)dihydrothio]thioxanthone, 2-[(diphenyl)dihydrothio]thioxanthone, 4-[4-(4-tert-butylbenzyl)phenylthio]phenyldi-p-tolylcathionium, 4-[4-(benzylphenylthio)]phenyldiphenylcathionium, 5-(4-methoxyphenyl)thianthrenium, 5-phenylthianthrenium, diphenylbenzylmethylcathionium, 4-hydroxyphenylmethylbenzylcathionium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylcathionium, 4-hydroxyphenylmethylbenzylmethylcathionium, and octadecylmethylbenzylmethylcathionium.

In formula (B-1), ^X- is a counter ion. The number of counter ions per molecule is p+1. The counter ion is not particularly limited, and examples thereof include boron compounds, phosphorus compounds, antimony compounds, arsenic compounds, halides such as alkylsulfonic acid compounds, and methyl compounds. X ^- , for example: halogen ions such as F ^- , Cl ^- , Br ^- , and I ^- ; OH ^- ; ClO ₄ ^- ; sulfonic acid ions such as FSO ₃ ^- , ClSO ₃ ^- , CH ₃ SO ₃ ^- , C ₆ H ₅ SO ₃ ^- , and CF ₃ SO ₃ ^- ; sulfuric acid ions such as HSO ₄ ^- , SO ₄ ^{2- ,} and the like; carbonate ions such as HCO ₃ ^- , CO ₃ ^2- , and the like; phosphate ions such as H ₂ PO ₄ ^- , HPO ₄ ^2- , and PO ₄ ^3- ; fluorophosphate ions such as PF ₆ ^- , PF ₅ OH ^- , and fluorinated alkyl fluorophosphate ions; BF ₄ ^- , B(C ₆ F ₅ ) ₄ ^- , and B(C ₆ H ₄ CF ₃ ) ₄ ^- and other borate ions; AlCl ₄ ^- ; BiF ₆ ^- , etc. Fluoroantimonate ions such as SbF ₆ ^- and SbF ₅ OH ^- , and fluoroarsenate ions such as AsF ₆ ^- and AsF ₅ OH ^- can also be cited.

Examples of the fluorinated alkyl fluorophosphate ion include fluorinated alkyl fluorophosphate ions represented by formula (B-1-3). [(Rf) _b PF _6-b ] ^- (B-1-3)

In formula (B-1-3), Rf represents an alkyl group substituted with a fluorine atom. The number b of Rf is 1 to 5, preferably an integer. The b Rfs may be the same or different. The number b of Rf is more preferably 2 to 4, and most preferably 2 to 3.

In the fluorinated alkyl fluorophosphate ion represented by formula (B-1-3), Rf represents a fluorine-substituted alkyl group, preferably having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms. Examples of the alkyl group include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and octyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, and tert-butyl; and cycloalkyl groups such as _{cyclopropyl ,} cyclobutyl, _cyclopentyl , _and cyclohexyl. Specific examples of Rf include _{CF3 , CF3CF2} , ( _CF3 ) _{2CF , CF3CF2CF2} , _CF3CF2CF2CF2 , (CF3) _{2CFCF2 , CF3CF2 (CF3 ) CF} , and ( _CF3 ) _3C .

Specific examples of ideal fluorinated alkyl fluorophosphoric acid anions include [(CF ₃ CF ₂ ) ₂ PF ₄ ] ^- , [(CF ₃ CF ₂ ) ₃ PF ₃ ] ^- , [((CF ₃ ) ₂ CF) ₂ PF ₄ ] ^- , [((CF ₃ ) ₂ CF) ₃ PF ₃ ] ^- , [(CF ₃ CF ₂ CF ₂ ) ₂ PF ₄ ] ^- , [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ^- , [((CF ₃ ) ₂ CFCF ₂ ) ₂ PF ₄ ] ^- , [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ^- , [ ₍ CF ₃ CF ₂ CF ₂ ) ₂ PF ₄ ] ^- and [(CF ₃ CF ₂ CF ₂ CF ₂ ) ₃ PF ₃ ] ^- etc.

For photocatalytic polymerization initiators, those pre-dissolved in solvents can be used to facilitate mixing with the polymerizable compound. Examples of solvents include carbonates such as propylene carbonate, ethyl carbonate, 1,2-butyl carbonate, dimethyl carbonate, and diethyl carbonate.

The photocatalytic polymerization initiator is preferably a compound represented by formula (1). Examples of the compound represented by formula (1) include triaryl coronium tris(pentafluorophenyl)borate, triaryl coronium hexafluoroantimonate, and triaryl coronium hexafluorophosphate. [Chemistry 8]

In formula (1), R ¹ represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, and X ^- represents a monovalent anion. Plural R ^1s may be the same or different.

Examples of the alkyl group in R ¹ include the same ones as the alkyl group having 1 to 30 carbon atoms in R 1 . Examples of the aryl group in R ¹ include the same ones as the aryl group having 6 to 30 carbon atoms in R 1 .

X ^- may be enumerated as above.

R ¹ is preferably an alkyl group which may have a substituent or an aryl group which may have a substituent, and more preferably an aryl group which may have a substituent.

The photoradical polymerization initiator is not particularly limited, and examples thereof include: Diphenyl ketone and its derivatives; Diphenylethanedione and its derivatives; Anthraquinone and its derivatives; Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, benzyl dimethyl ketal and other benzoin-type photopolymerization initiators; Acetophenone-type photopolymerization initiators such as diethoxyacetophenone and 4-tert-butyltrichloroacetophenone; 2-Dimethylaminoethyl benzoate; P-dimethylaminoethyl benzoate; Diphenyl disulfide; Thioxanthone and its derivatives; Camphorquinone-type photopolymerization initiators such as 7,7-dimethyl-2,3-dioxybiscyclo[2.2.1]heptane-1-carboxylic acid, 7,7-dimethyl-2,3-dioxybiscyclo[2.2.1]heptane-1-carboxylic-2-bromoethyl ester, 7,7-dimethyl-2,3-dioxybiscyclo[2.2.1]heptane-1-carboxylic-2-methyl ester, and 7,7-dimethyl-2,3-dioxybiscyclo[2.2.1]heptane-1-carboxylic acid chloride; α-Aminoalkylphenone-type photopolymerization initiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-thiazolinopropan-1-one and 2-benzyl-2-dimethylamino-1-(4-thiazolinophenyl)-butan-1-one; Acylphosphine oxide-type photopolymerization initiators such as benzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzyldiphenylphosphine oxide, benzoyldiethoxyphosphine oxide, 2,4,6-trimethylbenzyldimethoxyphenylphosphine oxide, 2,4,6-trimethylbenzyldiethoxyphenylphosphine oxide, and bis(2,4,6-trimethylbenzyl)phenylphosphine oxide; Methyl phenyl-glyoxylate; Oxyphenyl-acetic acid 2-[2-hydroxy-2-phenyl-acetyloxy-ethoxy]-ethyl ester; Oxyphenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, etc.

The content of the photopolymerization initiator is preferably 0.01 parts by mass or more relative to 100 parts by mass of the polymerizable compound, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more. This further enhances the curability. Furthermore, the content of the polymerization initiator is preferably 5 parts by mass or less relative to 100 parts by mass of the polymerizable compound, and even more preferably 3 parts by mass or less. This allows for the formation of a sealant with improved reliability for long-term storage. That is, the content of the photopolymerization initiator relative to 100 parts by mass of the polymerizable compound can be, for example, 0.01 to 5 parts by mass, 0.01 to 3 parts by mass, 0.1 to 5 parts by mass, 0.1 to 3 parts by mass, 0.3 to 5 parts by mass, 0.3 to 3 parts by mass, 0.5 to 5 parts by mass, or 0.5 to 3 parts by mass.

Inorganic particles that can be used include crystalline silica, amorphous silica, aluminum oxide, magnesium oxide, zirconium oxide, talc, mica, clay, kaolin, rutile titanium oxide, ferrous titanium oxide, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, aluminum hydroxide, and magnesium hydroxide. Spherical inorganic particles, such as spherical silica, spherical aluminum oxide, spherical magnesium oxide, and spherical zirconium oxide, are preferred. Spherical inorganic particles allow for random reflection of irradiation light at the interface between the polymerizable compound and the inorganic particles in the composition, allowing the irradiation light to more easily reach deeper into the composition, tending to achieve the desired curing depth as described above.

The average circularity (true roundness) of the inorganic particles is preferably 0.7 or greater, more preferably 0.8 or greater, and even more preferably 0.85 or greater. This tends to more significantly achieve the aforementioned effect of random reflection. The average circularity of the inorganic particles can be 1.0 or less.

In this specification, the average circularity of inorganic particles is calculated by measuring the projected area and circumference of primary particles of inorganic particles observed under a microscope using the following formula and averaging the calculated values. Average circularity = 4 × π × (projected area) / (circumference) ²

The inorganic particles preferably have a refractive index close to that of the polymerizable compound. The absolute value of the difference between the refractive index _n1 of the polymerizable compound and the refractive index _n2 of the inorganic particles (| _n1 - _n2 |) can be, for example, 0.6 or less, preferably 0.5 or less, more preferably 0.4 or less, even more preferably 0.3 or less, and even more preferably 0.25 or less, 0.2 or less, 0.15 or less, or 0.1 or less. By having a refractive index close to that of the polymerizable compound, the irradiated light is less likely to be reflected at the interface between the inorganic particles and the polymerizable compound, allowing the irradiated light to more easily reach deeper into the composition, which tends to more easily achieve the desired curing depth described above.

In this specification, the refractive index n ₂ of inorganic particles is calculated using the following formula: n ₂ = (n'-n)/v+n

When the composition of this embodiment contains multiple types of inorganic particles, the |n 1 -n 2 | of the inorganic particles with the highest content (e.g., 50 volume % or more, 60 volume % or more, 70 volume % or more, 80 volume % or more, or 90 volume % or more of the total amount of inorganic particles) is preferably within the above range. The |n _{1 -n 2 |} of all inorganic particles is even more preferably within the above range.

The refractive index n ₂ of the inorganic fine particles is not particularly limited, and is, for example, 1.3 or greater, preferably 1.4 or greater. Furthermore, the refractive index n ₂ of the inorganic fine particles is, for example, 2.5 or less, preferably 2.3 or less, more preferably 2.0 or less, even more preferably 1.8 or less, and even more preferably 1.6 or less. It may also be 1.5 or less. The refractive index n ₂ of the inorganic fine particles can be measured, for example, using an Abbe refractometer. Specifically, the refractive index n ₂ of the inorganic fine particles can be, for example, 1.3-2.5, 1.3-2.3, 1.3-2.0, 1.3-1.8, 1.3-1.6, 1.3-1.5, 1.4-2.5, 1.4-2.3, 1.4-2.0, 1.4-1.8, 1.4-1.6, or 1.4-1.5.

The average particle size of the inorganic particles can be, for example, 0.1 μm or greater, preferably 0.5 μm or greater, and more preferably 1 μm or greater. A larger average particle size of the inorganic particles tends to prevent water from penetrating the cured product. Alternatively, the average particle size of the inorganic particles can be, for example, 50 μm or less, preferably 30 μm or less, and more preferably 10 μm or less. A smaller average particle size of the inorganic particles makes it less likely that the inorganic particles will separate within the composition, resulting in a more uniform cured product and a tendency to improve long-term reliability. That is, the average particle size of the inorganic microparticles may be, for example, 0.1-50 μm, 0.1-30 μm, 0.1-10 μm, 0.5-50 μm, 0.5-30 μm, 0.5-10 μm, 1-50 μm, 1-30 μm, or 1-10 μm.

In this specification, the average particle size of inorganic fine particles represents the value measured by the laser diffraction scattering method using a MICROTRAC particle size distribution device.

The content of inorganic particles is 30% by volume or more, preferably 32% by volume or more, more preferably 35% by volume or more, and may be 40% by volume or more, or 45% by volume or more. By maintaining a sufficient hardening depth and increasing the content of inorganic particles, the moisture permeability of the hardened body tends to be lower. There is no particular upper limit on the content of inorganic particles as long as the aforementioned hardening depth can be maintained. The content of inorganic particles may be, for example, 80% by volume or less, preferably 70% by volume or less, more preferably 65% by volume or less, and may be 60% by volume or less, 55% by volume or less, or 50% by volume or less. By reducing the content of inorganic particles, it is easier to meet the aforementioned hardening depth. That is, the content of inorganic particles can be, for example: 30-80 volume%, 30-70 volume%, 30-65 volume%, 30-60 volume%, 30-55 volume%, 30-50 volume%, 32-80 volume%, 32-70 volume%, 32-65 volume%, 32-60 volume%, 32-55 volume%, 32-50 volume%, 35-80 volume%, 35-70 volume%, 3 5-65 volume%, 35-60 volume%, 35-55 volume%, 35-50 volume%, 40-80 volume%, 40-70 volume%, 40-65 volume%, 40-60 volume%, 40-55 volume%, 40-50 volume%, 45-80 volume%, 45-70 volume%, 45-65 volume%, 45-60 volume%, 45-55 volume% or 45-50 volume%.

The composition of this embodiment may further contain a photosensitizer. A photosensitizer is a compound that absorbs energy radiation and efficiently generates reactive species (e.g., cations generated from a photocationic polymerization initiator, free radicals generated from a photoradical polymerization initiator) from a polymerization initiator.

The photosensitizer is not particularly limited, and examples thereof include diphenyl ketone derivatives, phenanthrene derivatives, phenyl ketone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetraphenylene derivatives, derivatives, perylene derivatives, pentacene derivatives, acridine derivatives, benzothiazole derivatives, benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, anthraquinone derivatives, derivatives, xanthone derivatives, thiothionyl Derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, azinium derivatives, thioxanthone derivatives, thioxanthone derivatives, indoline derivatives, azulene derivatives, triallylmethane derivatives, phthalocyanine derivatives, spiropyran derivatives, spiropyran derivatives, thiospiropyran derivatives, and organic ruthenium complexes are also preferred. Among these, phenyl ketone derivatives such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one and anthracene derivatives such as 9,10-dibutoxyanthracene are preferred, and anthracene derivatives are even more preferred. Among anthracene derivatives, 9,10-dibutoxyanthracene is particularly preferred. The photosensitizer may be used alone or in combination of two or more.

An ideal photosensitizer is, for example, a photosensitizer represented by the following formula (2). A photosensitizer represented by the following formula (2) is, for example, dibutoxyanthracene. [Chemistry 9]

In formula (2), R ² represents an alkyl group which may have a substituent.

The carbon number of the alkyl group of R ² can be, for example, 1 to 10, preferably 2 to 8, and more preferably 2 to 6. That is, the carbon number of the alkyl group of R ² can be, for example, 1 to 10, 1 to 8, 1 to 6, 2 to 10, 2 to 8, or 2 to 6.

When the composition of this embodiment contains a photosensitizer, the content of the photosensitizer can be, for example, 0.01 parts by mass or greater, or 0.05 parts by mass or greater, relative to 100 parts by mass of the polymerizable compound. Furthermore, considering storage stability, the content of the photosensitizer can be, for example, 5 parts by mass or less, preferably 3 parts by mass or less, relative to 100 parts by mass of the polymerizable compound. Specifically, the content of the photosensitizer can be, for example, 0.01 to 5 parts by mass, 0.01 to 3 parts by mass, 0.05 to 5 parts by mass, or 0.05 to 3 parts by mass relative to 100 parts by mass of the polymerizable compound.

The composition of this embodiment may also contain other ingredients besides those listed above. Other ingredients, such as known additives used in the sealant field, may be used without particular limitation. Other ingredients include, for example, silane coupling agents, antioxidants, resin particles, metal passivating agents, fillers, stabilizers, neutralizers, lubricants, and antimicrobial agents.

The content of other components is not particularly limited, and may be, for example, 10% by mass or less, 5% by mass or less, or 1% by mass or less based on the total amount of the composition.

The method for producing the composition of this embodiment is not particularly limited; the components may be mixed using a mixing method that provides sufficient stirring to thoroughly mix the components. Examples of such mixing methods include methods using a known disperser that imparts rotational force to a stirrer such as a stirring blade, screw, or magnetic stirrer; methods using a rotating container such as a roller mixer or planetary mixer; methods using shear force generated by stirring balls such as a bead mill; methods using compression such as a roller mill; methods using vibration such as a vibrator; methods using turbulence in the mixture such as a vortex mixer; and methods using ultrasonic waves such as an ultrasonic mixer. Among these methods, stirring using a rotating container, such as a planetary mixer, is preferred from the perspective of thoroughly and safely mixing the components and minimizing impurities from the agitator. Examples of stirring methods using rotating containers include vacuum rotation and revolving mixers.

By curing the composition of this embodiment, a cured product containing a polymer of a polymerizable compound and inorganic particles can be obtained. This cured product has low moisture permeability and is suitable for use as a sealant (particularly a sealant for organic electroluminescent display devices and a dam in a dam-fill seal structure).

The composition of the present embodiment can be cured by irradiation with energy rays, for example. As for energy rays, ultraviolet light and visible light are suitable from the viewpoint of reaction efficiency and safety. The light source used in the curing of the composition of the present embodiment is not particularly limited, and examples include halogen lamps, metal halide lamps, high-power metal halide lamps (containing indium, etc.), low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, xenon excimer lamps, xenon flash lamps, light-emitting diodes (hereinafter referred to as LEDs), etc. In addition, natural light (sunlight) can also serve as a reaction start light source. Among these light sources, LED light sources are preferred from the viewpoint of being able to selectively irradiate the target wavelength.

The wavelength of the light source is not particularly limited and can be appropriately selected based on the reaction wavelength of the polymerization initiator. To improve reactivity, the wavelength can be set to 400 nm or less, preferably 395 nm or less, more preferably 385 nm or less, and even more preferably 365 nm or less. To improve curing depth, the wavelength can be set to 300 nm or more, preferably 320 nm or more, more preferably 340 nm or more, and even more preferably 365 nm or more. That is, the wavelength of the above-mentioned light source can be, for example: 300-400nm, 300-395nm, 300-385nm, 300-365nm, 320-400nm, 320-395nm, 320-385nm, 320-365nm, 340-400nm, 340-395nm, 340-385nm, 340-365nm, 365-400nm, 365-395nm or 365-385nm.

The above-mentioned method of irradiating with a light source may be direct irradiation or focused irradiation using a reflector, fiber, etc. Furthermore, irradiation using a low-wavelength cutoff filter, a heat-ray cutoff filter, a cold mirror, etc. is also possible.

The irradiation dose of the aforementioned light source can also be appropriately selected based on the thickness of the composition. For example, for a composition with a thickness of 100 μm, the irradiation dose is preferably 600 mJ/ ^cm² or greater, and more preferably 1000 mJ/ ^cm² or greater. Furthermore, for compositions with a thickness less than 100 μm, the irradiation dose can also be appropriately adjusted based on the thickness (e.g., proportional to the thickness).

During curing of the composition of this embodiment, a post-heating treatment may be performed after light irradiation to accelerate curing. To avoid adverse effects on the organic electroluminescent display element, the post-heating temperature is preferably 150°C or lower, more preferably 100°C or lower, and may also be 90°C or lower or 80°C or lower. The post-heating temperature is preferably 40°C or higher, but may also be 50°C or higher, 60°C or higher, 70°C or higher, or 80°C or higher. Specifically, the post-heating temperature may be, for example, 40-150°C, 40-100°C, 40-90°C, 40-80°C, 50-150°C, 50-100°C, 50-90°C, 50-80°C, 60-150°C, 60-100°C, 60-90°C, 60-80°C, 70-150°C, 70-100°C, 70-90°C, or 70-80°C. Furthermore, to avoid adverse effects on the organic electroluminescent display element, the post-treatment time is preferably 120 minutes or less, more preferably 60 minutes or less, and even more preferably 30 minutes or less. The post-treatment time may be 5 minutes or longer, 10 minutes or longer, 20 minutes or longer, and even more preferably 30 minutes or longer. That is, the post-treatment time may be, for example, 5-120 minutes, 5-60 minutes, 5-30 minutes, 10-120 minutes, 10-60 minutes, 10-30 minutes, 20-120 minutes, 20-60 minutes, 20-30 minutes, 30-120 minutes, or 30-60 minutes.

The composition of this embodiment can also be used as an adhesive. The composition of this embodiment can be preferably used for bonding packages such as organic electroluminescent display devices.

A method for bonding two components using the composition of this embodiment includes, for example, the following steps: applying the composition to the entirety or a portion of a first component; irradiating the composition applied to the first component with light; and, while the irradiated composition hardens, bonding the first component to the second component via the intervening composition. This method allows the second component to be bonded to the first component without being exposed to light or heat. Therefore, this method is ideal for bonding back panels to organic electroluminescent display devices.

A method for manufacturing an organic electroluminescent display device using the composition of this embodiment includes, for example, the following steps: applying the composition to a back panel; irradiating the composition applied to the back panel with light; and shielding the light and bonding the back panel to a substrate on which the organic electroluminescent display element is formed, through the composition. This method allows the organic electroluminescent display element to be sealed without being exposed to light or heat.

Furthermore, a method for manufacturing an organic electroluminescent display device using the composition of this embodiment may include, for example, the following steps: coating the composition on one substrate; bonding one substrate to another substrate via the composition; and irradiating the composition between the substrates with light to cure the composition.

The composition of this embodiment, when irradiated with light having a wavelength of 365 nm and ^an irradiation dose of 600 mJ/cm² and left at 80°C for 30 minutes, exhibits a hardening depth of 100 μm or greater. The hardening depth is preferably 120 μm or greater, more preferably 140 μm or greater, even more preferably 160 μm or greater, and even more preferably 180 μm or greater. It may also be 200 μm or greater, 250 μm or greater, 300 μm or greater, 350 μm or greater, 400 μm or greater, 450 μm or greater, or 500 μm or greater. A greater hardening depth suppresses the degradation of moisture resistance and reliability caused by residual unreacted monomer, tending to achieve superior moisture resistance and long-term reliability. There is no particular upper limit to the hardening depth. The hardening depth may be, for example, 1000 μm or less, preferably 800 μm or less, and more preferably 700 μm or less. That is, the hardening depth may be, for example, 100-1000 μm, 100-800 μm, 100-700 μm, 120-1000 μm, 120-800 μm, 120-700 μm, 140-1000 μm, 140-800 μm, 140-700 μm, 160-1000 μm, 160-800 μm, 160-700 μm, 180-1000 μm, 180-800 μm, 180-700 μm, 200-1000 μm, 200-800 μm, 200-1000 μm, 200-800 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200-2000 μm, 200 0～700μm, 250～1000μm, 250～800μm, 250～700μm, 300～1000μm, 300～800μm, 300～700μm, 350～1000μm, 350～800μm, 350～70 0μm, 400～1000μm, 400～800μm, 400～700μm, 450～1000μm, 450～800μm, 450～700μm, 500～1000μm, 500～800μm or 500～700μm.

The composition of this embodiment can be adjusted appropriately in terms of the type and content of each component to achieve a curing depth within the above range.

The specific gravity of the cured product of the composition of this embodiment (hereinafter also simply referred to as the cured product of this embodiment) is, for example, 1.3 or greater, preferably 1.5 or greater, and more preferably 1.7 or greater. Furthermore, the specific gravity of the cured product of this embodiment can be, for example, 5.0 or less, preferably 3.0 or less. That is, the specific gravity of the cured product of this embodiment can be, for example, 1.3 to 5.0, 1.3 to 3.0, 1.5 to 5.0, 1.5 to 3.0, 1.7 to 5.0, or 1.7 to 3.0. Furthermore, the specific gravity of the cured product represents a value measured in accordance with JIS K7112 method B using 23°C water as the immersion liquid.

The composition of this embodiment can appropriately adjust the types and contents of the various components to ensure that the specific gravity of the hardened body falls within the above range.

In the cured body of this embodiment, the glass transition temperature of the polymer of the polymerizable compound can be, for example, 80°C or higher, preferably 85°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher. The glass transition temperature of the polymer of the polymerizable compound can be, for example, 250°C or lower.

In this specification, the glass transition temperature (Tg) of a polymer is a value obtained from dynamic viscoelasticity spectroscopy. The glass transition temperature is defined as the temperature at which the storage modulus decreases and the peak of the loss tangent (hereinafter referred to as tanδ) is observed in the dynamic viscoelasticity spectrum when a solid polymer is subjected to a stress and strain at a certain temperature and then heated at a certain heating rate.

The composition of this embodiment can appropriately adjust the types and contents of the various components to bring the glass transition temperature of the polymer into the above range.

The viscosity of the composition of this embodiment is, for example, 0.1 Pa·s or greater, preferably 1 Pa·s or greater, more preferably 10 Pa·s or greater, and even more preferably 100 Pa·s or greater. A high viscosity of the composition reduces flow during curing, making it easier to obtain a cured product with stable dimensions. The viscosity of the composition of this embodiment is, for example, 10,000 Pa·s or less, preferably 1,000 Pa·s or less. A low viscosity facilitates processing and handling of the composition. In other words, the viscosity of the composition of this embodiment can be 0.1-10,000 Pa·s, 0.1-1,000 Pa·s, 1-10,000 Pa·s, 1-1,000 Pa·s, 10-10,000 Pa·s, 10-1,000 Pa·s, 100-10,000 Pa·s, or 100-1,000 Pa·s. Viscosity refers to the value measured at 23°C using a tapered plate viscometer in accordance with JIS K5600 2-3.

The moisture permeability of the cured article of this embodiment, measured at a temperature of 85°C and a relative humidity of 85% in accordance with JIS Z0208, is preferably 150 g/(m ² ･24 hours) or less, more preferably 130 g/(m ² ･24 hours) or less, even more preferably 100 g/(m ² ･24 hours) or less, and even more preferably 80 g/(m ² ･24 hours) or less. It may be 60 g/(m ² ･24 hours) or less, and may be 50 g/(m ² ･24 hours) or less. The above-mentioned moisture permeability can also be referred to as the moisture permeability (g/m ² ) at a thickness of 100 μm, measured in an environment of 85°C and 85% RH for 24 hours in accordance with JIS Z 0208:1976. The above-mentioned moisture permeability may be, for example, 0.01 (g/m ² · 24 hours) or greater, 0.1 (g/m ² · 24 hours) or greater, 1 (g/m ² · 24 hours) or greater, or 5 (g/m ² · 24 hours) or greater. That is, the moisture permeability may be, for example, 0.01-150 g/(m ² ･24 hours), 0.01-130 g/(m ² ･24 hours), 0.01-100 g/(m ² ･24 hours), 0.01-80 g/(m ² ･24 hours), 0.01-60 g/(m ² ･24 hours), 0.01-50 g/(m ² ･24 hours), 0.1-150 g/(m ² ･24 hours), 0.1-130 g/(m ² ･24 hours), 0.1-100 g/(m ^{2 ･24 hours), 0.1-80 g/(m 2} ･24 hours), 0.1-60 g/(m ² ･24 hours), 0.1-50 g/(m ² ･24 hours), ² ･24 hours), 1-150g/(m ² ･24 hours), 1-130g/(m ² ･24 hours), 1-100g/(m ² ･24 hours), 1-80g/(m ² ･24 hours), 1-60g/(m ² ･24 hours), 1-50g/(m ² ･24 hours), 5-150g/(m ² ･24 hours), 5-130g/(m 2 ･24 hours), 5-100g/(m ² ･24 hours), 5-80g ^{/(m 2 ･24 hours), 5-60g/(m 2 ･ 24} hours), or 5-50g/(m ² ･24 hours).

The composition of this embodiment can appropriately adjust the types and contents of the various components to ensure that the moisture permeability of the cured product falls within the above range.

The water absorption rate of the cured body of this embodiment, under conditions of a temperature of 85°C and a relative humidity of 85% for 24 hours, can be, for example, 15% or less, preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. It can also be 2% or less, 1.5% or less, or 1% or less. This suppresses the degradation of moisture resistance and reliability caused by residual moisture in the cured body, tending to achieve superior moisture resistance and long-term reliability.

The composition of this embodiment can appropriately adjust the types and contents of the various components to ensure that the water absorption rate of the cured product falls within the above range.

The above description is based on the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments.

For example, the present invention may also relate to a method for manufacturing an organic electroluminescent display device having a dam-filling and sealing structure, comprising the steps of coating and curing the above-mentioned composition to form a dam.

Furthermore, the present invention may also relate to an organic electroluminescent display device having a bank-filled sealing structure composed of a bank and a filler. In this case, the bank may also contain a cured product of the above-mentioned composition.

Furthermore, the dam-fill sealing structure can be a known dam-fill sealing structure, and the filler can also be a known filler. Furthermore, the components of the organic electroluminescent display device other than the dam-fill sealing structure can also be the same as those of the known organic electroluminescent display device.

The organic electroluminescent display element can also be an organic electroluminescent television. The present invention provides a sealant that achieves sufficient moisture resistance and long-term reliability in significantly larger organic electroluminescent televisions. [Examples]

The following examples illustrate the present invention in more detail, but the present invention is not limited to these examples. Unless otherwise specified, the examples were tested at 23°C and a relative humidity of 50% by mass.

The following compounds were used in the Examples and Comparative Examples.

(A) Polymerizable Compounds (A-1) Glycidyl methacrylate ("LIGHT ESTER G" manufactured by Kyoeisha Chemical Co., Ltd., specific gravity: 1.1, refractive index: 1.45, molecular weight 142) (A-2) Neopentyl glycol diglycidyl ether ("ED523T" manufactured by ADEKA, specific gravity: 1.1, refractive index: 1.48, molecular weight 216) (A-3) Tetrabromobisphenol A diglycidyl ether ("EPICLON 152" manufactured by DIC Corporation, specific gravity: 1.7, refractive index: 1.60, molecular weight 972) (A-4) 3',4'-Epoxyepoxyhexylmethyl-3,4-epoxyepoxyhexanecarboxylate ("CELLOXIDE 2021" manufactured by Daicell Chemical Co., Ltd., specific gravity: 1.2, refractive index: 1.52, molecular weight 252) (A-5) 1,10-Decanediol dimethacrylate ("NK Ester DOD-N" manufactured by Shin-Nakamura Chemical Co., Ltd., specific gravity: 1.0, refractive index: 1.46)

(B) Polymerization Initiator (B-1) Triarylthium tris(pentafluorophenyl)borate ("CPI-310B" manufactured by San-apro) (B-2) Benzyl dimethyl ketal ("Irgacure TPO" manufactured by BASF)

(C) Inorganic fine particles (C-1) Spherical silica (Denka Corporation "FB-5SDC", average particle size: 4 μm, circularity: 0.9, refractive index: 1.44, specific gravity 2.1) (C-2) Spherical alumina (Denka Corporation "DAW-05", average particle size: 5 μm, circularity: 0.95, refractive index: 1.77, specific gravity 3.9) (C-3) Plate-shaped talc (Matsumura Corporation "HIFFLER #17", average particle size: 12 μm, circularity: 0.5, refractive index: 1.57, specific gravity 2.7) (C-4) Rutile titanium oxide (Ishihara Corporation "CR-EL", average particle size: 0.25 μm, circularity: 0.7, refractive index: 2.13, specific gravity 4.2)

(D) Photosensitizer (D-1) Dibutoxyanthracene (Kawasaki Chemical Industries, Ltd., "ANTHRACURE UVS-1331")

(Examples 1-7 and Comparative Examples 1-4) The raw materials listed in Tables 1-3 were weighed in the proportions shown and stirred for 5 minutes at 600 rpm in a vacuum rotary mixer (EME "UFO-S3") to prepare the compositions of the Examples and Comparative Examples. The blending ratios are expressed in parts by mass. The content of inorganic fine particles was expressed as volume % by volume, calculated from the specific gravity.

The following values were determined for each composition in the Examples and Comparative Examples. The results are shown in Tables 1 to 3.

<Refractive Index of Polymers of Polymerizable Compounds> A polymerizable compound and polymerization initiator were weighed in the proportions shown in Tables 1-3 and stirred at 2000 rpm for 5 minutes using a THINKY AR-250 mixer to obtain a mixture. The mixture was then coated onto a polyethylene terephthalate film to a thickness of 100 μm and irradiated with ultraviolet light at a dose of 600 mJ/ ^cm² using a 365 nm LED light source. The film was then left to stand at 80°C for 30 minutes. The polyethylene terephthalate film was then peeled off to obtain a test sample. The refractive index of the obtained test sample was measured using an Abbe refractometer (ATAGO DR-M2).

<Cure Depth> The composition was filled into a urethane tube with an inner diameter of 4mm and a depth of 8mm, the sides and bottom of which were coated with aluminum foil. The tube was then irradiated with UV light at a dose of 600mJ/ ^cm² from above using a 365nm LED light source on an 80°C hot plate. After irradiation, the tube was left to stand at 80°C for 30 minutes. The uncured portion at the bottom of the tube was wiped off with a gauze soaked in ethanol, and the thickness of the remaining cured portion was measured using a micrometer (Mitsutoyo Co., Ltd.).

<Total Light Transmittance and Total Light Reflectance> The composition was coated on glass to a thickness of 100 μm, and then glass was layered on top, creating a three-layer structure of glass/composition/glass. After baseline calibration using two uncoated sheets of glass, the total light transmittance and total light reflectance of the three-layer structure were measured using a haze meter (Nippon Denshoku "NDH-8000").

<Preparation of the Cured Body> The composition was applied to a polyethylene terephthalate film to a thickness of 100 μm. The film was then irradiated with ultraviolet light at a dose of 600 mJ/ ^cm² from a 365 nm LED light source and allowed to stand at 80°C for 30 minutes. The polyethylene terephthalate film was then peeled off to obtain the cured body.

<Refractive Index Difference> Using the refractive index n ₁ of the polymer of the polymerizable compound and the refractive index n ₂ of the inorganic fine particles determined by the above method, the refractive index difference was calculated using the following formula. However, when the composition contains multiple inorganic fine particles, |n ₁ - n ₂ | is calculated for each inorganic fine particle, and the maximum value is reported in the table. Refractive Index Difference = |n ₁ - _{n 2} |. Furthermore, in Example 6, the maximum value of |n ₁ - n ₂ | is 0.57, but inorganic fine particles with |n ₁ - _{n 2} | of 0.5 or less ((C-1) spherical silica) account for the majority of the inorganic fine particles.

<Specific Gravity of Hardened Parts> The specific gravity of hardened parts was measured using a Mettler-Toledo specific gravity measurement kit. The measurement atmosphere was set at 23°C.

Moisture Permeability The moisture permeability of the cured product was measured at 85°C, 85% RH, and for 24 hours. All other conditions were determined using the moisture cup method in accordance with JIS Z 0208.

Moisture Absorption Rate (Water Absorption Rate) The hardened material was placed in a 23°C, 50% RH environment for 24 hours, then humidified in an 85°C, 85% RH environment for 24 hours. The material was then cooled to 23°C, 50% RH for 1 hour. The moisture content (%) was then measured using the Karl Fischer method. This value is defined as the moisture absorption rate.

Next, side sealing substrates were fabricated using the following methods for each composition of the Examples and Comparative Examples. The curing state of the sealing material was evaluated and reliability tests were performed. The results are shown in Tables 1-3.

<Preparation of the Side Sealing Substrate> Using a tabletop coater (SHOTmini, manufactured by Musashi Engineering Co., Ltd.) with a 0.2 mm diameter nozzle, 4 mL of the composition was applied to a 30 mm square of alkali-free glass, forming a square approximately 17 mm square. This formed the first glass substrate. Next, a 13 mm square glass substrate (manufactured by Q-Lights) with a 0.2 μm thick layer of metallic calcium vapor-deposited was prepared as the second glass substrate. The first and second glass substrates were then bonded together. The first and second glass substrates were aligned so that the composition on the first glass substrate surrounded the metallic calcium on the second glass substrate. After irradiating the first glass substrate with ultraviolet light at a wavelength of 365 nm and a dose of 600 mJ/ ^cm² , the substrate was pressed using a vacuum press at 40°C and a load of 0.1 MPa. The substrate was then heated in an oven at 80°C for 30 minutes, resulting in a side-sealed substrate sealed with a sealant made from the cured composition.

<Evaluation of Curing Status> Visually inspect the side sealant substrate. A rating is given if there are no uncured areas of the sealant material. A rating is given if uncured areas are observed.

<Reliability Test> The side-sealed substrate was placed in an 85°C, 85% RH atmosphere. The time required for the black metal calcium layer to completely turn white due to reaction with water was measured.

[Table 1] Example 1 Example 2 Example 3 Example 4 Polymerizable compound (parts by mass) (A-1) 80 - - - (A-2) - 80 - - (A-3) - - 60 60 (A-4) 10 20 40 40 (A-5) 10 - - - Polymerization initiator (parts by mass) (B-1) 0.5 1 0.5 1 (B-2) 0.5 - - - Inorganic particles (mass) (C-1) 120 180 - 240 (C-2) - - 300 60 (C-3) - - - - (C-4) - - - - Photosensitizer (mass) (D-1) - - 0.5 - Inorganic particle content (volume %) 55 65 73 76 Refractive index of polymer of polymerizable compound (n ₁ ) 1.46 1.49 1.56 1.56 Refractive index difference (|n ₁ -n ₂ |) (maximum value) 0.02 0.05 0.21 0.21 Total light transmittance (T ₀ (%)) 60 42 53 58 Total light reflectance (R ₀ (%)) 39 43 25 twenty two T ₀ +R ₀ 99 85 78 80 Hardening depth (μm) 800 520 280 190 Specific gravity of hardened body 1.5 1.6 2.7 2.1 Moisture permeability (g/m ² ･24h) 74 47 twenty two 9 Moisture absorption rate (%) 1.3 0.5 0.8 1.8 Curing state of sealing substrate A A A A Reliability test of sealing substrate (hr) 864 1008 1200 1344

[Table 2] Example 5 Example 6 Example 7 Polymerizable compound (parts by mass) (A-1) - - - (A-2) - - - (A-3) 60 60 - (A-4) 40 40 - (A-5) - - 100 Polymerization initiator (parts by mass) (B-1) 1 1 - (B-2) - - 0.5 Inorganic particles (mass) (C-1) 40 120 100 (C-2) - - 100 (C-3) 40 - - (C-4) - 40 - Photosensitizer (mass) (D-1) - - 0.1 Inorganic particle content (volume %) 42 62 65 Refractive index of polymer of polymerizable compound (n ₁ ) 1.56 1.56 1.46 Refractive index difference (|n ₁ -n ₂ |) (maximum value) 0.01 0.57 0.31 Total light transmittance (T ₀ (%)) 61 5 50 Total light reflectance (R ₀ (%)) 35 93 15 T ₀ +R ₀ 96 98 65 Hardening depth (μm) 630 170 120 Specific gravity of hardened body 1.8 2.0 1.8 Moisture permeability (g/m ² ･24h) 96 83 98 Moisture absorption rate (%) 3.6 12.2 2.2 Curing state of sealing substrate A A A Reliability test of sealing substrate (hr) 600 840 576

[Table 3] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Polymerizable compound (parts by mass) (A-1) 80 - - - (A-2) - 80 - - (A-3) - - 60 - (A-4) 10 20 40 - (A-5) 10 - - 100 Polymerization initiator (parts by mass) (B-1) - 1 1 - (B-2) 1 - - 0.1 Inorganic particles (mass) (C-1) - - - 100 (C-2) - - - 100 (C-3) - 40 - - (C-4) - - 160 - Photosensitizer (mass) (D-1) - - - - Inorganic particle content (volume %) 0 27 54 65 Refractive index of polymer of polymerizable compound (n ₁ ) 1.46 1.49 1.56 1.46 Refractive index difference (|n ₁ -n ₂ |) (maximum value) - 0.08 0.57 0.31 Total light transmittance (T ₀ (%)) 100 79 0 50 Total light reflectance (R ₀ (%)) 0 16 37 15 T ₀ +R ₀ 100 95 37 65 Hardening depth (μm) >1000 240 20 40 Specific gravity of hardened body 1.1 1.3 2.5 1.8 Moisture permeability (g/m ² ･24h) 528 183 399 280 Moisture absorption rate (%) 0.8 1.2 32.5 19.5 Curing state of sealing substrate A A C C Reliability test of sealing substrate (hr) 120 312 72 168

Claims (16)

A composition comprising: a polymerizable compound comprising at least one selected from the group consisting of alicyclic epoxy compounds and non-epoxy compounds; inorganic fine particles comprising at least one selected from the group consisting of spherical silica, spherical alumina, spherical magnesium oxide, and spherical zirconium oxide; and a photopolymerization initiator, wherein the content of the inorganic fine particles is at least 30% by volume. The composition is filled into a urethane tube having an inner diameter of 4 mm and a depth of 8 mm, the sides and bottom of which are coated with aluminum foil. The tube is then irradiated with ultraviolet light having a wavelength of 600 mJ/ ^cm² from the top of the tube on a hot plate at 80°C. The cured film is left at 80°C for 30 minutes, and the cured film has a depth of at least 100 μm. The composition of claim 1, wherein the inorganic fine particles have a refractive index n ₂ such that the absolute value of the difference between the refractive index n ₁ of the polymer of the polymerizable compound (|n ₁ - n ₂ |) is 0.5 or less. The composition of claim 1 or 2, wherein the refractive index _n2 of the inorganic fine particles is greater than 1.4. The composition of claim 1 or 2, wherein the average circularity of the inorganic fine particles is not less than 0.7 and not more than 1.0. The composition of claim 1 or 2, wherein the inorganic fine particles contain at least one selected from the group consisting of spherical silica and spherical alumina. The composition of claim 1 or 2, wherein the sum of the total light transmittance T ₀ (%) and the total light reflectance R ₀ (%) (T ₀ +R ₀ ) at a thickness of 100 μm is 50% or more. The composition of claim 1 or 2, wherein the photopolymerization initiator contains a compound represented by the following formula (1): In formula (1), R ¹ represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, and X ⁻ represents a monovalent anion. Multiple R ^1s may be the same or different.   The composition of claim 1 or 2 further contains a photosensitizer represented by the following formula (2): In formula (2), R ² represents an alkyl group which may have a substituent; multiple R ² groups may be the same or different. The composition of claim 1 or 2 is a composition for forming a cured product having a moisture permeability of not more than 100 g/(m ² ･24 hours) per 100 μm thickness, as measured at a temperature of 85°C and a relative humidity of 85% in accordance with JIS Z0208. The composition of claim 1 or 2 is a composition for forming a hardened body having a water absorption rate of 3% or less after 24 hours at a temperature of 85°C and a relative humidity of 85%. The composition of claim 1 or 2 is a sealant for an organic electroluminescent display device. The composition of claim 1 or 2 is a sealant for forming a cofferdam in a cofferdam filling method. A composition comprises: a polymerizable compound comprising at least one selected from the group consisting of alicyclic epoxy compounds and non-epoxy compounds; inorganic fine particles having a refractive index n ₂ such that the absolute value of the difference between the refractive index n ₁ of a polymer of the polymerizable compound (|n ₁ - n ₂ |) is 0.5 or less, and at least one selected from the group consisting of spherical silica, spherical alumina, spherical magnesium oxide, and spherical zirconium oxide; and a photopolymerization initiator, wherein the content of the inorganic fine particles is 30 volume % or more, the content of the photopolymerization initiator is 0.3 parts by mass or more relative to 100 parts by mass of the polymerizable compound, and the average circularity of the inorganic fine particles is 0.7 or more and 1.0 or less. A hardened body, which is a hardened body of the composition according to any one of claims 1 to 13. An organic electroluminescent display device comprises: an organic electroluminescent display element; and a sealing structure comprising a dam and a filler for sealing the organic electroluminescent display element, wherein the dam contains the hardened body according to claim 14. The organic electroluminescent display device of claim 15 is an organic electroluminescent television.