KR102917801B1 - Composition, curing agent and organic EL display device - Google Patents

Abstract

A composition containing 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 amount of 600 mJ/cm2 and left to stand at 80°C for 30 minutes, the depth of curing is 100 μm or more.

Description

Composition, curing agent and organic EL display device

The present invention relates to a composition, a cured product, and an organic EL display device.

Recently, research is being conducted on organic optical devices using organic thin-film elements such as organic electroluminescent (organic EL) display elements and organic thin-film solar cell elements.

Organic EL display devices have a thin film structure in which an organic light-emitting material layer is sandwiched between a pair of opposing electrodes. Electrons are injected into the organic light-emitting material layer from one electrode, while holes are simultaneously injected from the other electrode. As a result, the electrons and holes combine within the organic light-emitting material layer to emit light. Compared to liquid crystal displays and other devices that require a backlight, organic EL display devices have the advantages of superior visibility, the ability to be thinner, and the ability to be driven by low-voltage DC.

However, these organic EL displays have the problem that their luminescent properties deteriorate rapidly when the organic light-emitting material layer or electrodes are exposed to the outside air, shortening their lifespan. Therefore, in order to increase the stability and durability of organic EL displays, sealing technology that blocks the organic light-emitting material layer or electrodes from moisture and oxygen in the air has become essential.

For example, Patent Document 1 discloses a method of filling a photocurable sealant between organic EL display substrates and sealing them by irradiating light, in a top-emitting organic EL display device, etc.

[Patent Document 1] Japanese Patent Publication No. 2001-357973

Recently, with the increase in the size of organic EL displays (especially organic EL televisions), there is a demand for sealants that can realize higher moisture resistance and long-term reliability.

The present invention has been made in consideration of the above circumstances, and 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 an organic EL display device comprising a cured product of the composition and a sealing structure formed using the composition.

The present invention relates to, for example, the following <1> to <18>.

<1> A composition containing 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 the composition is irradiated with light having a wavelength of 365 nm and an irradiation amount of 600 mJ/cm2, and has a curing depth of 100 μm or more when left to stand at 80°C for 30 minutes.

<2> The composition described in <1>, wherein the polymerizable compound has at least one polymerizable group selected from the group consisting of carbon-carbon double bonds and cyclic ethers.

<3> The composition described in <1> or <2>, wherein the inorganic fine particles are inorganic fine particles having a refractive index n ₂ such that the absolute value of the difference (|n ₁ -n ₂ |) between the inorganic fine particles and the refractive index n ₁ of the polymer of the polymerizable compound is 0.5 or less.

<4> A composition according to any one of <1> to <3>, wherein the refractive index n ₂ of the above-mentioned inorganic fine particles is 1.4 or more.

<5> A composition according to any one of <1> to <4>, wherein the average circularity of the inorganic fine particles is 0.7 or more and 1.0 or less.

<6> A composition according to any one of <1> to <5>, wherein the inorganic fine particles comprise at least one selected from the group consisting of spherical silica and spherical alumina.

<7> A composition according to any one of <1> to <6>, wherein the sum of the total light transmittance T ₀ (%) and the total light reflectance R ₀ (%) per 100㎛ of thickness (T ₀ + R ₀ ) is 50% or more.

<8> A composition according to any one of <1> to <7>, wherein the photopolymerization initiator comprises 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.]

<9> A composition according to any one of <1> to <8>, further containing a photosensitizer represented by the following formula (2).

[In formula (2), R ² represents an alkyl group that may have a substituent. Multiple R ^2s may be the same or different.]

<10> A composition according to any one of <1> to <9> for forming a cured body having a moisture permeability of 100 g/(㎡·24 hours) or less per 100 ㎛ of thickness measured under conditions of a temperature of 85°C and a relative humidity of 85% in accordance with JIS Z0208.

<11> A composition according to any one of <1> to <10> for forming a cured body having an absorption rate of 3% or less at a temperature of 85°C and a relative humidity of 85% for 24 hours.

<12> A composition according to any one of <1> to <11>, which is a sealant for an organic EL display device.

<13> A composition according to any one of <1> to <12>, which is a sealant for forming a dam using a dam-fill method.

<14> A composition containing a polymerizable compound, inorganic fine particles having a refractive index n ₂ such that the absolute value of the difference (|n ₁ -n ₂ |) between the polymerizable compound and the refractive index n ₁ of the polymer 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 with respect 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.

<15> A cured product of the composition described in any one of <1> to <14>.

<16> An organic EL display device comprising a sealing structure including an organic EL display element, a dam for sealing the organic EL display element, and a filler, wherein the dam includes a cured material as described in <15>.

<17> An organic EL display device described in <16>, which is an organic EL television.

According to the present invention, a composition capable of forming a sealant with excellent moisture resistance and long-term reliability is provided. Furthermore, according to the present invention, an organic EL display device comprising a cured product of the composition and a sealing structure formed using the composition is provided.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The composition of the present embodiment contains a polymerizable compound, inorganic fine particles, and a photopolymerization initiator. In the composition of the present embodiment, the content of the inorganic fine particles is 30% by volume or more. The composition of the present embodiment has a curing depth of 100 μm or more when subjected to light irradiation at a wavelength of 365 nm and an irradiation dose of 600 mJ/cm2 and left to stand at 80°C for 30 minutes.

The composition of the present embodiment can form a sealant with excellent moisture resistance and long-term reliability. Therefore, the composition of the present embodiment can be preferably used as a sealant (preferably a sealant for organic EL display elements, and particularly preferably a sealant for organic EL televisions). Furthermore, the composition of the present embodiment can be particularly preferably used as a sealant for forming a dam in a dam-fill method (a sealing structure composed of a dam and a filler).

The reason why the composition of the present embodiment exhibits the above-described effect is not necessarily limited, but is thought to be as follows. According to the composition of the present embodiment, a cured product containing a large amount of inorganic fine particles having lower moisture permeability than the resin material is formed. Furthermore, when the content of inorganic fine particles in the composition is increased, the inorganic fine particles tend to inhibit light irradiation, thereby increasing the amount of unreacted monomer (unreacted polymerizable compound) in the cured product. However, in the present embodiment, since it has the above-described depth of curing, the unreacted monomer is sufficiently reduced by light irradiation during sealing, and the deterioration of moisture resistance and reliability due to the unreacted monomer is suppressed. In other words, in the present embodiment, it is thought that excellent moisture resistance and long-term reliability are realized by formulating a composition having a predetermined depth of curing while blending sufficient inorganic fine particles.

In the present embodiment, the polymerizable compound may be referred to as a compound having a polymerizable group. One type of the polymerizable compound may be used alone, or two or more types may be used in combination.

As a polymerizable compound, it is preferable to have at least one polymerizable group selected from the group consisting of carbon-carbon double bonds and cyclic ethers.

The carbon-carbon double bond may be a carbon-carbon double bond having radical polymerization or cationic polymerization. Examples of compounds having a carbon-carbon double bond include compounds having polymerizable groups such as a (meth)acryloyl group, a vinyl group, an allyl group, a vinyl ether group, and a vinyl ester group. Among these, compounds having a (meth)acryloyl group ((meth)acrylate compounds) are preferred.

Examples of (meth)acrylate compounds include monofunctional (meth)acrylates having one (meth)acryloyl group, polyfunctional (meth)acrylates having two or more (meth)acryloyl groups, etc.

Examples of monofunctional (meth)acrylates include alkyl (meth)acrylates (e.g., ethyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, etc.), benzyl (meth)acrylate, ethoxylated-o-phenylphenol (meth)acrylate, etc.

Examples of multifunctional (meth)acrylates include alkanediol di(meth)acrylates (e.g., 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, etc.), tricyclodecane dimethanol di(meth)acrylate, etc.

The cyclic ether can be any cyclic ether with cationic polymerization. Examples of compounds containing cyclic ether include epoxy compounds and oxetane compounds.

Examples of epoxy compounds include alicyclic compounds having an epoxy group (alicyclic epoxy compounds), aromatic compounds having an epoxy group (aromatic epoxy compounds), and acyclic compounds having an epoxy group (acyclic epoxy compounds). One or more of these compounds may be selected and used.

Examples of the alicyclic epoxy compound include a compound obtained by epoxidizing a compound having at least one cycloalkene ring (e.g., a cyclohexene ring, a cyclopentene ring, a pinene ring, etc.) with a suitable oxidizing agent such as hydrogen peroxide or a peracid, or a derivative thereof. In addition, examples of the alicyclic epoxy compound include a hydrogenated epoxy compound obtained by hydrogenating an aromatic epoxy compound (e.g., a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, etc.).

Examples of alicyclic epoxy compounds include 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylalkyl(meth)acrylate (e.g., 3,4-epoxycyclohexylmethyl(meth)acrylate, etc.), (3,3',4,4'-diepoxy)bicyclohexyl, hydrogenated bisphenol A type epoxy resin, and hydrogenated bisphenol F type epoxy resin.

Among the alicyclic epoxy compounds, an alicyclic epoxy compound having a 1,2-epoxycyclohexane structure is preferred. Among the alicyclic epoxy compounds having a 1,2-epoxycyclohexane structure, a compound represented by the following formula (A1-1) is preferred.

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

The connecting group is preferably a divalent hydrocarbon group, a carbonyl group, an ether bond, an ester bond, a carbonate group, an amide bond, or a group in which multiple of these are connected.

X is preferably a linking group. As the linking group, a group having an ester bond is preferable. As a compound having a group having an ester bond as the linking group, an example thereof is 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

The molecular weight of the alicyclic epoxy compound is preferably 1000 or less, more preferably 450 or less, even more preferably 400 or less, still more preferably 300 or less, and particularly preferably 100 to 280, from the viewpoint of further improving the moisture resistance of the cured product and further improving the storage stability of the composition. That is, the molecular weight of the alicyclic epoxy compound may be, for example, 100 to 1000, 100 to 450, 100 to 400, 100 to 300, or 100 to 280.

When the alicyclic epoxy compound has a molecular weight distribution, it is preferable that the number average molecular weight of the alicyclic epoxy compound is within the above range. In addition, in this specification, the number average molecular weight represents a value converted to polystyrene measured by gel permeation chromatography (GPC) under the following measurement conditions.

ㆍSolvent (mobile phase): THF

Degassing device: ERC-3310 manufactured by ERMA

Pump: PU-980 manufactured by Nippon Kogakusha

ㆍFlow rate: 1.0ml/min

ㆍAuto sampler: AS-8020 manufactured by Dososa

Column oven: L-5030 manufactured by Hitachi, Ltd.

ㆍSet temperature: 40℃

ㆍColumn configuration: 2 TSK guard columns MP(×L) 6.0mmID×4.0cm manufactured by Tosoh Corporation, and 2 TSK-GELMULTIPORE HXL-M 7.8mmID×30.0cm manufactured by Tosoh Corporation, total of 4

Detector: RI Hitachi L-3350

ㆍData processing: SIC480 data station

Any of monomers, oligomers, or polymers can be used as the aromatic epoxy compound, and examples thereof 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 ethers, and modified products thereof.

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

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 alkyl group having 1 to 5 carbon atoms which may have a substituent. n may be 0.1 or more.

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, but are preferably the same.

It is preferable that the aromatic epoxy compound having a bisphenol structure is at least one selected from the group consisting of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

The molecular weight of the aromatic epoxy compound is preferably 100 to 5000, more preferably 150 to 1000, and even more preferably 200 to 450, from the viewpoint of further improving the moisture resistance of the cured product. That is, the molecular weight of the aromatic epoxy compound may be, for example, 100 to 5000, 100 to 1000, 100 to 450, 150 to 5000, 150 to 1000, 150 to 450, 200 to 5000, 200 to 1000, or 200 to 450.

When the aromatic epoxy compound has a molecular weight distribution, it is preferable that the number average molecular weight of the aromatic epoxy compound is within the above range. In addition, in this specification, the number average molecular weight refers to a polystyrene equivalent value measured under the above-described measurement conditions by gel permeation chromatography (GPC).

Examples of acyclic 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 polyhydric alcohols (e.g., di- or triglycidyl ethers of glycerin or its alkylene oxide adducts, etc.), diglycidyl ethers of polyalkylene glycols (e.g., diglycidyl ethers of polyethylene glycol or its alkylene oxide adducts, diglycidyl ethers of polypropylene glycol or its alkylene oxide adducts, etc.). Here, examples of alkylene oxides include ethylene oxide and propylene oxide.

Examples of oxetane compounds include, but are not particularly limited to, 3-ethyl-3-hydroxymethyloxetane (product name: Alonoxetane OXT-101, manufactured by Doah Synthetic Co., Ltd., etc.), 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene (same as OXT-121, etc.), 3-ethyl-3-(phenoxymethyl)oxetane (same as OXT-211, etc.), di(1-ethyl-(3-oxetanyl))methyl ether (same as OXT-221, etc.), 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane (same as OXT-212, etc.). An oxetane compound refers to a compound having one or more oxetane rings in the molecule.

As polymerizable compounds, compounds having both carbon-carbon double bonds and cyclic ethers can be used. Examples of polymerizable compounds having carbon-carbon double bonds and cyclic ethers include glycidyl (meth)acrylate, epoxycyclohexyl (meth)acrylate, 3-ethyloxetan-3-ylmethyl (meth)acrylate, epoxy-4-vinylcyclohexane, and 3-ethyloxetan-3-ylmethylvinyl ether.

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

The photocationic polymerization initiator is not particularly limited and includes, for example, arylsulfonium salt derivatives (for example, Cyracure UVI-6990 and Cyracure UVI-6974 manufactured by Dow Chemical Company, Adeka Optomer SP-150, Adeka Optomer SP-152, Adeka Optomer SP-170 and Adeka Optomer SP-172 manufactured by Adeka Corporation, CPI-100P, CPI-101A, CPI-200K, CPI-210S, CPI-310B, CPI-310FG, CPI-400S. LW-S1 manufactured by San-Apro Corporation, Chiba Cure 1190 manufactured by Double Bond Corporation, etc.), aryliodonium salt derivatives (for example, Irgacure 250 manufactured by Chiba Specialty Chemicals, Rhodia Japan, etc.) Examples thereof include acid generators such as RP-2074), allene-ion complex derivatives, diazonium salt derivatives, triazine-based initiators, and other halogenated compounds.

As a photo-cationic polymerization initiator, an onium salt represented by formula (B-1) can be mentioned, for example.

[In formula (B-1),

A represents an element of group VIA to VIIA with valence m,

m represents 1 to 2,

p represents 0 to 3,

R represents the organic group bonded to A,

D is the following formula (B-1-1):

A divalent group represented by (Formula (B-1-1) in which E represents a divalent group, G represents -O-, -S-, -SO-, -SO ₂ -, -NH-, -NR'-, -CO-, -COO-, -CONH-, an alkylene or phenylene group having 1 to 3 carbon atoms (R' represents an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms), a represents 0 to 5. a+1 E and a G may be the same or different), and X ^- is a counterion of onium.)

The onium ion of formula (B-1) is not particularly limited and includes, for example, 4-(phenylthio)phenyldiphenylsulfonium, bis[4-(diphenylsulfonio)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]sulfonio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)sulfonio]phenyl}sulfide, 4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, Examples thereof include 2-[(di-p-tolyl)sulfonio]thioxanthone, 2-[(diphenyl)sulfonio]thioxanthone, 4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 5-(4-methoxyphenyl)thianthrenium, 5-phenylthiaanthrenium, diphenylphenacylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, and octadecylmethylphenacylsulfonium.

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, and these may have a substituent. As a substituent, for example, at least one selected from the group consisting of an alkyl group, a hydroxy 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 alkyleneoxy group, an amino group, a cyano group, a nitro group, and a halogen can be mentioned.

The number of R is m+p(m-1)+1, and they may be the same or different. In addition, two or more R 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 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 aryl groups having 6 to 30 carbon atoms include monocyclic aryl groups such as a phenyl group, and condensed polycyclic aryl groups such as a naphthyl group, anthracenyl group, phenanthrenyl group, pyrenyl group, chrysenyl group, naphthacenyl group, benzanthracenyl group, anthraquinolyl group, fluorenyl group, naphthoquinone group, and anthraquinone group.

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 may have at least one substituent. Examples of the substituent include straight-chain alkyl groups having 1 to 18 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, and oxadecyl;

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 group;

A straight-chain or branched alkoxy group having 1 to 18 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, decyloxy, and dodecyloxy;

A straight-chain or branched alkylcarbonyl group having 2 to 18 carbon atoms, such as acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, octanoyl, decanoyl, dodecanoyl, and octadecanoyl;

Arylcarbonyl group having 7 to 11 carbon atoms, such as benzoyl and naphthoyl;

A straight-chain or branched alkoxycarbonyl group having 2 to 19 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, octyloxycarbonyl, tetradecyloxycarbonyl, or octadecyloxycarbonyl;

Aryloxycarbonyl group having 7 to 11 carbon atoms, such as phenoxycarbonyl and naphthoxycarbonyl;

Arylthiocarbonyl group having 7 to 11 carbon atoms, such as phenylthiocarbonyl and naphthoxycarbonyl;

A straight-chain or branched acyloxy group having 2 to 19 carbon atoms, such as acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, or 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)phenyl]phenylthio, 4-(phenylthio)phenylthio, Arylthio groups having 6 to 20 carbon atoms, such as 4-benzoylphenylthio, 4-benzoyl-2-chlorophenylthio, 4-benzoyl-3-chlorophenylthio, 4-benzoyl-3-methylthiophenylthio, 4-benzoyl-2-methylthiophenylthio, 4-(4-methylthiobenzoyl)phenylthio, 4-(2-methylthiobenzoyl)phenylthio, 4-(p-methylbenzoyl)phenylthio, 4-(p-ethylbenzoyl)phenylthio 4-(p-isopropylbenzoyl)phenylthio, and 4-(p-tert-butylbenzoyl)phenylthio;

A straight-chain or branched alkylthio group having 1 to 18 carbon atoms, such as methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, sec-butylthio, tert-butylthio, pentylthio, isopentylthio, neopentylthio, tert-pentylthio, octylthio, decylthio, or dodecylthio;

Aryl groups having 6 to 10 carbon atoms, such as phenyl, tolyl, dimethylphenyl, and naphthyl;

Heterocyclic groups having 4 to 20 carbon atoms, such as thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, quinolyl, isoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thianthrenyl, phenoxazinyl, phenoxathiinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, thioxanthonyl, and dibenzofuranyl;

Aryloxy group having 6 to 10 carbon atoms, such as phenoxy and naphthyloxy;

A straight-chain or branched alkylsulfinyl group having 1 to 18 carbon atoms, such as methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, butylsulfinyl, sec-butylsulfinyl, tert-butylsulfinyl, pentylsulfinyl, isopentylsulfinyl, neopentylsulfinyl, tert-pentylsulfinyl, and octylsulfinyl;

Arylsulfinyl group having 6 to 10 carbon atoms, such as phenylsulfinyl, tolylsulfinyl, and naphthylsulfinyl;

A straight-chain or branched alkylsulfonyl group having 1 to 18 carbon atoms, such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, tert-pentylsulfonyl, and octylsulfonyl;

Arylsulfonyl group having 6 to 10 carbon atoms, such as phenylsulfonyl, tolylsulfonyl (tosyl group), and naphthylsulfonyl;

Formula (B-1-2):

An alkyleneoxy group represented by (Q represents a hydrogen atom or a methyl group, and k represents an integer from 1 to 5);

Unsubstituted amino group;

An amino group mono- or disubstituted with an alkyl group having 1 to 5 carbon atoms and/or an aryl group having 6 to 10 carbon atoms;

cyano group;

Nitro;

Examples include 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.

Preferred onium ions [A ⁺ ] in formula (B-1) are sulfonium, iodonium, and selenium, but representative examples include the following.

As sulfonium ions, triphenylsulfonium, tri-p-tolylsulfonium, tri-o-tolylsulfonium, tris(4-methoxyphenyl)sulfonium, 1-naphthyldiphenylsulfonium, 2-naphthyldiphenylsulfonium, tris(4-fluorophenyl)sulfonium, tri-1-naphthylsulfonium, tri-2-naphthylsulfonium, tris(4-hydroxyphenyl)sulfonium, 4-(phenylthio)phenyldiphenylsulfonium, 4-(p-tolylthio)phenyldi-p-tolylsulfonium, 4-(4-methoxyphenylthio)phenylbis(4-methoxyphenyl)sulfonium, 4-(phenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(phenylthio)phenylbis(4-methoxyphenyl)sulfonium, 4-(Phenylthio)phenyldi-p-tolylsulfonium, bis[4-(diphenylsulfonio)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]sulfonio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)sulfonio]phenyl}sulfide, bis{4-[bis(4-methylphenyl)sulfonio]phenyl}sulfide, bis{4-[bis(4-methoxyphenyl)sulfonio]phenyl}sulfide, 4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoyl-2-chlorophenylthio)phenyldiphenylsulfonium, 4-(4-benzoylphenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 7-Isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium, 7-Isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, 2-[(di-p-tolyl)sulfonio]thioxanthone, 2-[(diphenyl)sulfonio]thioxanthone, 4-[4-(4-t-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium, 4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldiphenylsulfonium, 4-[4-(benzoylphenylthio)]phenyldi-p-tolylsulfonium, 4-[4-(benzoylphenylthio)]phenyldiphenylsulfonium, 5-(4-methoxyphenyl)thianthrenium, Triarylsulfoniums such as 5-phenylthiuanthreonium, 5-tolylthiuanthreonium, 5-(4-ethoxyphenyl)thiuanthreonium, and 5-(2,4,6-trimethylphenyl)thiuanthreonium;

Diarylsulfoniums such as diphenylphenacylsulfonium, diphenyl4-nitrophenacylsulfonium, diphenylbenzylsulfonium, and diphenylmethylsulfonium;

Monoarylsulfoniums such as phenylmethylbenzylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 4-methoxyphenylmethylbenzylsulfonium, 4-acetocarbonyloxyphenylmethylbenzylsulfonium, 2-naphthylmethylbenzylsulfonium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylsulfonium, phenylmethylphenacylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, 4-methoxyphenylmethylphenacylsulfonium, 4-acetocarbonyloxyphenylmethylphenacylsulfonium, 2-naphthylmethylphenacylsulfonium, 2-naphthyloctadecylphenacylsulfonium, and 9-anthracenylmethylphenacylsulfonium;

Trialkylsulfoniums such as dimethylphenacylsulfonium, phenacyltetrahydrothiophenium, dimethylbenzylsulfonium, benzyltetrahydrothiophenium, and octadecylmethylphenacylsulfonium; etc.

Among these onium ions, at least one composed of a sulfonium ion and an iodonium ion is preferable, and a sulfonium ion is more preferable. As sulfonium ions, triphenylsulfonium, tri-p-tolylsulfonium, 4-(phenylthio)phenyldiphenylsulfonium, bis[4-(diphenylsulfonio)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]sulfonio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)sulfonio]phenyl}sulfide, 4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, At least one selected from the group consisting of 2-[(di-p-tolyl)sulfonio]thioxanthone, 2-[(diphenyl)sulfonio]thioxanthone, 4-[4-(4-tert)-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium, 4-[4-(benzoylphenylthio)]phenyldiphenylsulfonium, 5-(4-methoxyphenyl)thianthrenium, 5-phenylthiaanthrenium, diphenylphenacylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, and octadecylmethylphenacylsulfonium is preferred.

In formula (B-1), X ^- is a counterion. The number of counterions is p + 1 per molecule. The counterion is not particularly limited, but may include halides such as boron compounds, phosphorus compounds, antimony compounds, arsenic compounds, alkylsulfonic acid compounds, methide compounds, etc. As X ^{- ,} for example, halogen ions such as F ^- , Cl ^- , Br ^- , I ^- ; OH ^- ; ClO ₄ ^- ; sulfonic acid ions such as FSO ₃ ^- , ClSO ₃ ^- , CH ₃ SO ₃ - , C ₆ H ₅ SO ₃ ^- , CF ₃ SO ₃ ^- ; sulfate ions such as HSO ₄ ^- , SO ₄ ^2- ; carbonate ions such as HCO ₃ ^- , CO ₃ ^2- ; phosphate ions such as H ₂ PO ₄ ^- , HPO ₄ ^2- , PO ₄ ^3- ; Examples include fluorophosphate ions such as PF ₆ ^- , PF ₅ OH ^- , and fluorinated alkylfluorophosphate ions; boric acid ions such as BF ₄ ^- , B(C ₆ F ₅ ) ₄ ^- , and B(C ₆ H ₄ CF ₃ ) ₄ ^- ; AlCl ₄ ^- ; and BiF ₆ ^- . In addition, examples include fluoroantimonic acid ions such as SbF ₆ ^- , SbF ₅ OH ^{- ,} and fluoroarsenic acid ions such as AsF ₆ ^- , AsF ₅ OH ^- .

Examples of the fluorinated alkylfluorophosphate ion include fluorinated alkylfluorophosphate ions represented by formula (B-1-3), etc.

[(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, and is 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 alkylfluorophosphate ion represented by formula (B-1-3), Rf represents an alkyl group substituted with a fluorine atom, and the preferred number of carbon atoms is 1 to 8, and more preferred number of carbon atoms is 1 to 4. Examples of the alkyl group include straight-chain 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 CF ₃ , CF ₃ CF ₂ , (CF ₃ ) ₂ CF, CF ₃ CF ₂ CF ₂ , CF ₃ CF ₂ CF _{2 ,} (CF ₃ ) ₂ CFCF ₂ , CF ₃ CF ₂ (CF ₃ )CF, (CF ₃ ) ₃ C, etc.

Specific examples of preferred fluorinated alkylfluorophosphate 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 ) ₃ PF ₃ ] ^- , [( _{CF 3 ) 2} CFCF _{2 ) 2} PF ₄ ] ^- and [(CF ₃ CF ₂ CF ₂ CF ₂ ) ₃ PF ₃ ] ^- can be mentioned.

The photocationic polymerization initiator may be dissolved in a solvent in advance to facilitate mixing with the polymerizable compound. Examples of such solvents include carbonates such as propylene carbonate, ethylene carbonate, 1,2-butylene carbonate, dimethyl carbonate, and diethyl carbonate.

As a photo-cationic polymerization initiator, a compound represented by the chemical formula (1) is preferable. Examples of the compound represented by the chemical formula (1) include triarylsulfonium tris(pentafluorophenyl)borate, triarylsulfonium hexafluoroantimonate, and triarylsulfonium hexafluorophosphate.

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.

As the alkyl group in R ¹ , the same group as the alkyl group having 1 to 30 carbon atoms in R can be exemplified. In addition, as the aryl group in R ¹ , the same group as the aryl group having 6 to 30 carbon atoms in R can be exemplified.

X ^- The same can be exemplified 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.

There is no particular limitation on the photo-radical polymerization initiator, but

Benzophenone and its derivatives;

Benzyl and its derivatives;

Anthraquinone and its derivatives;

Benzoin-type photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, and benzyl dimethyl ketal;

Acetophenone type photopolymerization initiators such as diethoxyacetophenone and 4-tert-butyltrichloroacetophenone;

2-Dimethylaminoethylbenzoate;

p-dimethylaminoethylbenzoate;

diphenyl disulfide;

Thioxanthone and its derivatives;

Camphorquinone-type photopolymerization initiators such as camphorquinone, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-bromoethyl ester, 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-methyl ester, and 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid chloride;

α-Aminoalkylphenone type photopolymerization initiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, etc.;

Acylphosphine oxide type photopolymerization initiators such as benzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, benzoyldiethoxyphosphine oxide, 2,4,6-trimethylbenzoyldimethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiethoxyphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide;

Phenyl-glyoxylic acid-methyl ester;

Oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester;

Oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester; etc.

The content of the photopolymerization initiator is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, still more preferably 0.3 parts by mass or more, and still more preferably 0.5 parts by mass or more, per 100 parts by mass of the polymerizable compound. This further improves curability. Furthermore, the content of the polymerization initiator is preferably 5 parts by mass or less, and still more preferably 3 parts by mass or less, per 100 parts by mass of the polymerizable compound. This makes it possible to form a sealant with excellent reliability for long-term storage. That is, the content of the photopolymerization initiator may 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, per 100 parts by mass of the polymerizable compound.

As the inorganic fine particles, crystalline silica, amorphous silica, alumina, magnesia, zirconia, talc, mica, clay, kaolin, rutile type titanium dioxide, anatase type titanium dioxide, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, aluminum hydroxide, magnesium hydroxide, etc. can be used. As the inorganic fine particles, spherical inorganic fine particles such as spherical silica, spherical alumina, spherical magnesia, and spherical zirconia can be suitably used. If the inorganic fine particles are spherical, the irradiation light is diffusely reflected at the interface between the polymerizable compound in the composition and the inorganic fine particles, making it easier for the irradiation light to reach deep into the composition, and thus tends to more easily satisfy the above-described suitable curing depth.

The average circularity (roundness) of the inorganic fine 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 diffuse reflection effect. The average circularity of the inorganic fine particles may be 1.0 or less.

In addition, the average circularity of the inorganic fine particles in this specification is the average value calculated by measuring the projected area and perimeter length of the primary particles of the inorganic fine particles observed by microscopic observation and using the following formula.

Average circularity = 4 × π × (projected area) / (perimeter) ²

It is preferable that the inorganic fine particles have a refractive index close to that of the polymerizable compound. The absolute value of the difference between the refractive index n ₁ of the polymer of the polymerizable compound and the refractive index n ₂ of the inorganic fine particles (|n ₁ -n ₂ |) may 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, still more preferably 0.25 or less, and may also be 0.2 or less, 0.15 or less, or 0.1 or less. Since the inorganic fine particles have a refractive index close to that of the polymerizable compound, reflection of irradiation light is less likely to occur at the interface between the inorganic fine particles and the polymerizable compound, making it easier for irradiation light to reach deep into the composition, and thus tends to more easily satisfy the above-described suitable curing depth.

In addition, in this specification, the refractive index n ₂ of the inorganic fine particles is a value calculated using the following equation, by measuring the refractive index n' of a mixture in which a liquid having a known refractive index n is used as a standard sample, and inorganic fine particles are dispersed in the standard sample at a predetermined volume fraction v using a refractometer.

n ₂ =(n'-n)/v+n

When the composition of the present embodiment includes multiple types of inorganic fine particles, it is preferable that |n 1 -n 2 | of the inorganic fine particles having the highest content (for example, 50 vol% or more, 60 vol% or more, 70 vol% or more, 80 vol% or more, or 90 vol% or more based on the total amount of inorganic fine particles) is within the above range, and it is more preferable that |n _{1 -n 2 |} of all inorganic fine particles is 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 more, preferably 1.4 or more. In addition, 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, still more preferably 1.6 or less, and may be 1.5 or less. The refractive index n ₂ of the inorganic fine particles is measured, for example, by an Abbe refractometer. That is, the refractive index n ₂ of the inorganic fine particles may be, for example, 1.3 to 2.5, 1.3 to 2.3, 1.3 to 2.0, 1.3 to 1.8, 1.3 to 1.6, 1.3 to 1.5, 1.4 to 2.5, 1.4 to 2.3, 1.4 to 2.0, 1.4 to 1.8, 1.4 to 1.6 or 1.4 to 1.5.

The average particle size of the inorganic fine particles may be, for example, 0.1 μm or more, preferably 0.5 μm or more, and more preferably 1 μm or more. When the average particle size of the inorganic fine particles is large, the effect of inhibiting moisture penetration in the cured body is more easily obtained. In addition, the average particle size of the inorganic fine particles may be, for example, 50 μm or less, preferably 30 μm or less, and more preferably 10 μm or less. When the average particle size of the inorganic fine particles is small, it is difficult for the inorganic fine particles to be separated from the composition, making it easier to obtain a more uniform cured body, which tends to further improve long-term reliability. That is, the average particle size of the inorganic fine particles may be, for example, 0.1 to 50 μm, 0.1 to 30 μm, 0.1 to 10 μm, 0.5 to 50 μm, 0.5 to 30 μm, 0.5 to 10 μm, 1 to 50 μm, 1 to 30 μm, or 1 to 10 μm.

In addition, the average particle diameter of the inorganic fine particles in this specification represents a value measured by laser diffraction/scattering using a microtrack particle size distribution device.

The content of inorganic fine particles is 30 vol% or more, preferably 32 vol% or more, more preferably 35 vol% or more, and may also be 40 vol% or more or 45 vol% or more. By increasing the content of inorganic fine particles while maintaining a sufficient depth of curing, the moisture permeability of the cured body tends to decrease further. The upper limit of the content of inorganic fine particles is not particularly limited as long as the above-described depth of curing can be maintained. The content of inorganic fine particles may be, for example, 80 vol% or less, preferably 70 vol% or less, more preferably 65 vol% or less, and may also be 60 vol% or less, 55 vol% or less, or 50 vol% or less. By decreasing the content of inorganic fine particles, the above-described depth of curing tends to be more easily satisfied. That is, the content of inorganic fine particles is, for example, 30 to 80 vol%, 30 to 70 vol%, 30 to 65 vol%, 30 to 60 vol%, 30 to 55 vol%, 30 to 50 vol%, 32 to 80 vol%, 32 to 70 vol%, 32 to 65 vol%, 32 to 60 vol%, 32 to 55 vol%, 32 to 50 vol%, 35 to 80 vol%, 35 to 70 vol%, 35 to 65 vol%, 35 to 60 vol%, 35 to 55 vol%, 35 to 50 vol%, 40 to 80 vol%, 40 to 70 vol%, 40 to 65 vol%, It may be 40 to 60 vol%, 40 to 55 vol%, 40 to 50 vol%, 45 to 80 vol%, 45 to 70 vol%, 45 to 65 vol%, 45 to 60 vol%, 45 to 55 vol% or 45 to 50 vol%.

The composition of the present embodiment may further comprise a photosensitizer. The photosensitizer refers to a compound that can absorb energy rays and efficiently generate reactive species (e.g., cations generated from a photo-cationic polymerization initiator, radicals generated from a photo-radical polymerization initiator) from a polymerization initiator.

The photosensitizer is not particularly limited, and examples thereof include benzophenone derivatives, phenothiazine derivatives, phenylketone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, naphthacene derivatives, chrysene derivatives, perylene derivatives, pentacene derivatives, acridine derivatives, benzothiazole derivatives, benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, anthraquinone derivatives, xanthene derivatives, xanthone derivatives, thioxanthene derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, azine derivatives, thiazine derivatives, oxazine derivatives, indoline derivatives, azulene derivatives, triallylmethane derivatives, phthalocyanine derivatives, spiropyran derivatives, spiroxazine derivatives, thiosspiropyran derivatives, and organic ruthenium complexes. 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 preferable, and anthracene derivatives are more preferable. Among the anthracene derivatives, 9,10-dibutoxyanthracene is preferable. The photosensitizer may be used alone or in combination of two or more.

Suitable photosensitizers include, for example, photosensitizers represented by the following formula (2). Photosensitizers represented by the following formula (2) include, for example, dibutoxyanthracene.

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

The number of carbon atoms in the alkyl group of R ² may be, for example, 1 to 10, preferably 2 to 8, and more preferably 2 to 6. That is, the number of carbon atoms in the alkyl group of R ² may 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 the present embodiment includes a photosensitizer, the content of the photosensitizer may be, for example, 0.01 parts by mass or more, or 0.05 parts by mass or more, relative to 100 parts by mass of the polymerizable compound. In addition, from the viewpoint of storage stability, the content of the photosensitizer may be, for example, 5 parts by mass or less, or preferably 3 parts by mass or less, relative to 100 parts by mass of the polymerizable compound. That is, the content of the photosensitizer may 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 the present embodiment may further include other components in addition to those mentioned above. Examples of these other components include, without limitation, known additives used in the field of sealants. Examples of these other components include silane coupling agents, antioxidants, resin particles, metal deactivators, fillers, stabilizers, neutralizers, lubricants, antibacterial agents, and the like.

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

The method for producing the composition of the present embodiment is not particularly limited, and the above-described components may be mixed by a mixing method having a stirring ability that sufficiently mixes the above-described components. Examples of the mixing method include a method of stirring by applying rotational force to a stirrer such as a stirring blade, screw, or magnetic stirrer; a method of stirring by rotating a container such as a tumbler mixer or a planetary stirrer; a method of stirring by utilizing the shear force of a stirring ball such as a bismill; a method of stirring by utilizing the compressive force of a roll mill; a method of stirring by utilizing the vibrational force of a shaker or the like; a method of stirring by utilizing the turbulence of the mixture itself such as a vortex mixer; a method of stirring by utilizing ultrasonic waves such as an ultrasonic stirrer; and a method of using a known disperser. Among these, a method of stirring by rotating a container such as a planetary stirrer is preferable from the viewpoint of sufficiently and safely mixing the above-described components and minimizing impurities in the stirrer or the like. A method of stirring by rotating a container includes a method using a vacuum autorotational revolution mixer.

By curing the composition of the present embodiment, a cured product comprising a polymer of a polymerizable compound and inorganic fine particles can be obtained. The cured product has low moisture permeability and can be suitably used as a sealant (particularly, a sealant for an organic EL display element, a dam in a dam-fill sealing structure).

The composition of the present embodiment can be cured, for example, by irradiation with energy rays. As the energy rays, ultraviolet light and visible light are preferably used from the viewpoints of reaction efficiency and safety. The light source used for curing the composition of the present embodiment is not particularly limited, but may include a halogen lamp, a metal halide lamp, a high-power metal halide lamp (containing indium, etc.), a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a xenon excimer lamp, a xenon flash lamp, a light-emitting diode (hereinafter referred to as “LED”), and the like. In addition, natural light (sunlight) can also be a reaction initiation light source. Among these light sources, an LED light source is preferable because it can selectively irradiate a target wavelength.

The wavelength of the light source is not particularly limited, and the light source is appropriately selected depending on the reaction wavelength of the polymerization initiator, etc. From the viewpoint of reactivity efficiency, the wavelength can be 400 nm or less, preferably 395 nm or less, more preferably 385 nm or less, and even more preferably 365 nm or less. Furthermore, from the viewpoint of curing depth efficiency, the wavelength can be 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 light source may be, for example, 300 to 400 nm, 300 to 395 nm, 300 to 385 nm, 300 to 365 nm, 320 to 400 nm, 320 to 395 nm, 320 to 385 nm, 320 to 365 nm, 340 to 400 nm, 340 to 395 nm, 340 to 385 nm, 340 to 365 nm, 365 to 400 nm, 365 to 395 nm or 365 to 385 nm.

The irradiation method using the above light source may be direct irradiation or focused irradiation using a reflector, fiber, etc. In addition, irradiation using a low wavelength cut filter, a heat ray cut filter, a cold mirror, etc. may also be used.

The irradiance of the above light source may be appropriately selected depending on the thickness of the composition. For example, the irradiance for a composition having a thickness of 100 μm is preferably 600 mJ/cm2 or more, and more preferably 1000 mJ/cm2 or more. Furthermore, for a composition having a thickness of less than 100 μm, the irradiance may be appropriately adjusted depending on the thickness (e.g., proportionally to the thickness).

In curing the composition of the present embodiment, post-heating treatment may be performed after light irradiation to promote curing. The temperature of the post-heating is preferably 150°C or lower, more preferably 100°C or lower, and may be 90°C or lower or 80°C or lower, from the viewpoint of avoiding influence on the organic EL display element. The temperature of the post-heating is preferably 40°C or higher, and may be 50°C or higher, 60°C or higher, 70°C or higher, or 80°C or higher. That is, the temperature of the post-heating may be, for example, 40 to 150°C, 40 to 100°C, 40 to 90°C, 40 to 80°C, 50 to 150°C, 50 to 100°C, 50 to 90°C, 50 to 80°C, 60 to 150°C, 60 to 100°C, 60 to 90°C, 60 to 80°C, 70 to 150°C, 70 to 100°C, 70 to 90°C, or 70 to 80°C. In addition, the time of the post-treatment is preferably 120 minutes or less, more preferably 60 minutes or less, and even more preferably 30 minutes or less from the viewpoint of avoiding influence on the organic EL display element. The post-processing time may be 5 minutes or more, 10 minutes or more, preferably 20 minutes or more, and more preferably 30 minutes or more. That is, the post-processing time may be, for example, 5 to 120 minutes, 5 to 60 minutes, 5 to 30 minutes, 10 to 120 minutes, 10 to 60 minutes, 10 to 30 minutes, 20 to 120 minutes, 20 to 60 minutes, 20 to 30 minutes, 30 to 120 minutes, or 30 to 60 minutes.

The composition of the present embodiment can also be used as an adhesive. The composition of the present embodiment can be suitably used for bonding, for example, packages such as organic EL display elements.

As a method for bonding two members using the composition of the present embodiment, a method including, for example, a step of applying the composition to the entire surface or a portion of a first member, a step of irradiating the composition applied onto the first member with light, and a step of bonding the first member and the second member via the composition until the composition that has been irradiated with light is cured. According to this method, the second member can be bonded onto the first member without being exposed to light or heat. Therefore, the method can be suitably used for bonding a back plate and an organic EL display element.

As a method for manufacturing an organic EL display device using the composition of the present embodiment, for example, a manufacturing method including a step of applying the composition onto a back plate, a step of irradiating light onto the composition applied onto the back plate, and a step of blocking the light and bonding the back plate and a substrate forming the organic EL display element via the composition can be exemplified. According to this method, the organic EL display element can be sealed without being exposed to light or heat.

In addition, as a method for manufacturing an organic EL display device using the composition of the present embodiment, a manufacturing method including, for example, a step of applying the composition to one substrate, a step of bonding one substrate and another substrate using the composition, and a step of curing the composition by irradiating light to the composition between the substrates may also be mentioned.

The composition of the present embodiment has a curing depth of 100 μm or more 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 curing depth is preferably 120 μm or more, more preferably 140 μm or more, even more preferably 160 μm or more, and still more preferably 180 μm or more, and may also be 200 μm or more, 250 μm or more, 300 μm or more, 350 μm or more, 400 μm or more, 450 μm or more, or 500 μm. When the value of the curing depth is large, the deterioration of moisture resistance and reliability due to the residue of unreacted monomer is suppressed, and better moisture resistance and long-term reliability tend to be realized. The upper limit of the curing depth is not particularly limited. The curing depth may be, for example, 1000 μm or less, preferably 800 μm or less, and more preferably 700 μm or less. That is, the above-mentioned hardening depth is, for example, 100 to 1000 μm, 100 to 800 μm, 100 to 700 μm, 120 to 1000 μm, 120 to 800 μm, 120 to 700 μm, 140 to 1000 μm, 140 to 800 μm, 140 to 700 μm, 160 to 1000 μm, 160 to 800 μm, 160 to 700 μm, 180 to 1000 μm, 180 to 800 μm, 180 to 700 μm, 200 to 1000 μm, 200 to 800 μm, 200 to 700 μm, 250 to 1000 μm, 250 to 800 μm, 250 to It may be 700㎛, 300 ~ 1000㎛, 300 ~ 800㎛, 300 ~ 700㎛, 350 ~ 1000㎛, 350 ~ 800㎛, 350 ~ 700㎛, 400 ~ 1000㎛, 400 ~ 800㎛, 400 ~ 700㎛, 450 ~ 1000㎛, 450 ~ 800㎛, 450 ~ 800㎛, 450 ~ 700㎛, 500 ~ 1000㎛, 500 ~ 800㎛, or 500 ~ 700㎛.

The composition of the present embodiment may have the types and contents of each component appropriately adjusted so that the curing depth falls within the above range.

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

In the composition of the present embodiment, the type and content of each component may be appropriately adjusted so that the specific gravity of the cured body is within the above range.

In the cured product of the present embodiment, the glass transition temperature of the polymer of the polymerizable compound may 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 may be, for example, 250°C or lower.

In addition, in this specification, the glass transition temperature (Tg) of a polymer represents a value obtained from a dynamic viscoelastic spectrum. In a dynamic viscoelastic spectrum, for a polymer that is solid at a certain temperature, when stress and strain are applied at that temperature and then heated at a constant temperature increase rate, the temperature at which the peak top of the loss tangent (hereinafter abbreviated as tanδ) appears along with a decrease in the storage modulus can be defined as the glass transition temperature.

In the composition of the present embodiment, the types and contents of each component may be appropriately adjusted so that the glass transition temperature of the polymer is within the above range.

The viscosity of the composition of the present embodiment is, for example, 0.1 Pa·s or more, preferably 1 Pa·s or more, more preferably 10 Pa·s or more, and even more preferably 100 Pa·s or more. When the viscosity of the composition is high, the flow is reduced during curing of the composition, and it is easy to obtain a cured body with stable dimensions. The viscosity of the composition of the present embodiment is, for example, 10,000 Pa·s or less, and preferably 1,000 Pa·s or less. When the viscosity of the composition is low, processing and handling of the composition become easy. That is, the viscosity of the composition of the present embodiment may be 0.1 to 10,000 Pa·s, 0.1 to 1,000 Pa·s, 1 to 10,000 Pa·s, 1 to 1,000 Pa·s, 10 to 10,000 Pa·s, 10 to 1,000 Pa·s, 100 to 10,000 Pa·s, or 100 to 1,000 Pa·s. In addition, the viscosity is in accordance with JIS K5600 2-3 method and represents a value measured at 23°C using a cone-plate viscometer method.

The cured product of the present embodiment preferably has a moisture permeability per 100 μm of thickness measured under conditions of a temperature of 85°C and a relative humidity of 85% in accordance with JIS Z0208 of 150 g/(㎡·24 hours) or less, more preferably 130 g/(㎡·24 hours) or less, still more preferably 100 g/(㎡·24 hours) or less, still more preferably 80 g/(㎡·24 hours) or less, and may be 60 g/(㎡·24 hours) or less, or 50 g/(㎡·24 hours) or less. In addition, the above moisture permeability can also be referred to as a moisture permeability (g/m ² ) at a thickness of 100 μm measured by exposing for 24 hours in an environment of 85°C and 85% RH in accordance with JIS Z 0208:1976. The above moisture permeability may be, for example, 0.01 (g/m ² ·24 hours) or more, 0.1 (g/m ² ·24 hours) or more, 1 (g/m ² ·24 hours) or more, or 5 (g/㎡ ·24 hours) or more. That is, the moisture permeability is, for example, 0.01 to 150g/(㎡·24 hours), 0.01 to 130g/(㎡·24 hours), 0.01 to 100g/(㎡·24 hours), 0.01 to 80g/(㎡·24 hours), 0.01 to 60g/(㎡·24 hours), 0.01 to 50g/(㎡·24 hours), 0.1 to 150g/(㎡·24 hours), 0.1 to 130g/(㎡·24 hours), 0.1 to 100g/(㎡·24 hours), 0.1 to 80g/(㎡·24 hours), 0.1 to 60g/(㎡·24 hours), 0.1 to 50g/(㎡·24 hours), 1 to 150g/(㎡·24 hours), It may be 1 to 130g/(㎡·24 hours), 1 to 100g/(㎡·24 hours), 1 to 80g/(㎡·24 hours), 1 to 60g/(㎡·24 hours), 1 to 50g/(㎡·24 hours), 5 to 150g/(m2·24 hours), 5 to 130g/(㎡·24 hours), 5 to 100g/(㎡·24 hours), 5 to 80g/(㎡·24 hours), 5 to 60g/(㎡·24 hours), or 5 to 50g/(㎡·24 hours).

In the composition of the present embodiment, the types and contents of each component may be appropriately adjusted so that the moisture permeability of the cured body is within the above range.

The cured product of the present embodiment may have an absorption rate of, for example, 15% or less at a temperature of 85°C and a relative humidity of 85% for 24 hours, preferably 10% or less, more preferably 5% or less, even more preferably 3% or less, and may also have an absorption rate of 2% or less, 1.5% or less, or 1% or less. As a result, the deterioration of moisture resistance and reliability due to the residual moisture in the cured product is suppressed, and there is a tendency for better moisture resistance and long-term reliability to be realized.

In the composition of the present embodiment, the types and contents of each component may be appropriately adjusted so that the absorption rate of the cured body is within the above range.

Above, the preferred embodiments of the present invention have been described, but the present invention is not limited to the above embodiments.

For example, the present invention may relate to a method for manufacturing an organic electroluminescent display device having a dam-fill sealing structure, including a process of forming a dam by applying and curing the composition.

In addition, the present invention relates to an organic EL display device having a dam-fill sealing structure including a dam and a fill, wherein the dam may include a cured product of the above-described composition.

In addition, the dam-fill sealing structure may be a known dam-fill sealing structure, and the fill may be a known fill. In addition, the configuration of the organic EL display device other than the dam-fill sealing structure may be the same as that of a known organic EL display device.

The above organic EL display element may be an organic EL television. According to the present invention, a sealant capable of realizing sufficient moisture resistance and long-term reliability can be provided for an organic EL television with a significant increase in size.

[Example]

Hereinafter, the present invention will be described in more detail by examples, 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.

In the examples and comparative examples, the following compounds were used.

(A) polymeric compound

(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, specific gravity: 1.7, refractive index: 1.60, molecular weight 972)

(A-4) 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate ("Celloxide 2021" manufactured by Daicel 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) Triarylsulfonium tris(pentafluorophenyl)borate (CPI-310B manufactured by San-Apro)

(B-2) Benzyl dimethyl ketal ("Irgacure TPO" manufactured by BASF)

(C) Inorganic particulate matter

(C-1) Spherical silica (manufactured by Denka Corporation, “FB-5SDC”, average particle size: 4 ㎛, circularity: 0.9, refractive index: 1.44, specific gravity 2.1)

(C-2) Spherical alumina (Denka Corporation "DAW-05", average particle size: 5 ㎛, roundness: 0.95, refractive index: 1.77, specific gravity 3.9)

(C-3) Plate-shaped talc (Matsumura Sangyo "High Filler #17", average particle size: 12 ㎛, roundness: 0.5, refractive index: 1.57, specific gravity 2.7)

(C-4) Rutile titanium dioxide (Ishihara Sangyo "CR-EL", average particle size: 0.25 ㎛, roundness: 0.7, refractive index: 2.13, specific gravity 4.2)

(D) Photosensitizer

(D-1) Dibutoxyanthracene (Kawasaki Kasei Industries, Ltd. "Anthracure UVS-1331")

(Examples 1 to 7 and Comparative Examples 1 to 4)

The raw materials shown in Tables 1 to 3 were weighed in the proportions shown in Tables 1 to 3, and mixed at 600 rpm for 5 minutes using a vacuum rotating orbital mixer (EMI "UFO-S3") to prepare compositions of examples and comparative examples. Furthermore, the mixing ratio is expressed in parts by mass. Furthermore, the content of inorganic fine particles is expressed as a volume percentage by calculating the volume ratio from the specific gravity.

The following values were obtained for each composition of the examples and comparative examples. The results are shown in Tables 1 to 3.

<Refractive index of polymer of polymerizable compound>

Polymerizable compounds and polymerization initiators were weighed in the proportions shown in Tables 1 to 3, and stirred and mixed at 2000 rpm for 5 minutes using a rotating rotational mixer (Sinkie "AR-250") to obtain a mixture. Next, the mixture was applied to a thickness of 100 μm on a polyethylene terephthalate film, irradiated with ultraviolet light at an irradiance of 600 mJ/cm2 using an LED light source having a wavelength of 365 nm, and allowed to stand at 80°C for 30 minutes. Thereafter, the polyethylene terephthalate film was peeled off to obtain a measurement sample. The refractive index of the obtained measurement sample was measured using an Abbe refractometer (Atago "DR-M2").

<Depth of hardening>

The composition was filled into a 4 mm inner diameter, 8 mm deep urethane tube covered on the sides and bottom with aluminum foil, and irradiated with ultraviolet light at an irradiance of 600 mJ/cm2 from the top of the tube on a hot plate at 80°C using an LED light source with a wavelength of 365 nm. After irradiation, the tube was left to stand at 80°C for 30 minutes, and the uncured portion at the bottom of the tube was wiped with gauze soaked in ethanol, and the thickness of the remaining cured portion was measured with a micrometer (manufactured by Mitutoyo Corporation).

<Total light transmittance, total light reflectance>

The composition was applied to a thickness of 100 μm on glass, and additional glass was overlapped on top to form a three-layer structure of glass/composition/glass. After performing base correction using two uncoated pieces of glass with a haze meter (Nippon Denshoku "NDH-8000"), the total light transmittance and total light reflectance were measured for the sample with the three-layer structure.

<Production of hardened body>

The composition was applied to a thickness of 100 μm on a polyethylene terephthalate film. Subsequently, the film was irradiated with ultraviolet light at a dose of 600 mJ/cm2 using an LED light source with a wavelength of 365 nm, and then left to stand at 80°C for 30 minutes. Thereafter, the polyethylene terephthalate film was peeled off to obtain a cured product.

<Difference in refractive index>

The refractive index n ₁ of the polymer of the polymerizable compound obtained by the above-described method and the refractive index n ₂ of the inorganic fine particles were used to calculate the value from the following equation. However, when the composition includes multiple inorganic fine particles, |n ₁ -n ₂ | was calculated for each inorganic fine particle, and the maximum value was recorded in the table.

Difference in refractive index = |n ₁ -n ₂ |

In addition, in Example 6, the maximum value of |n ₁ -n ₂ | is 0.57, but inorganic fine particles ((C-1) spherical silica) having |n ₁ -n ₂ | of 0.5 or less account for the majority of the inorganic fine particles.

<Specific gravity of hardened body>

The specific gravity of the cured product was measured using a Mettler Toledo specific gravity measurement kit. The measurement atmosphere was 23°C.

<Moisture permeability>

The moisture permeability of the cured product was measured according to the moisture permeability cup method of JIS Z 0208, except that the test conditions were 85°C, 85% RH, and the time was 24 hours.

<Moisture absorption rate>

After the cured product was left to stand for 24 hours in an atmosphere of 23℃ and 50% RH, it was humidified for 24 hours in an atmosphere of 85℃ and 85% RH, and then cooled again to 23℃ and 50% RH for 1 hour. The moisture content (%) was measured using the Curl Fischer method, and this value was taken as the moisture absorption rate.

Next, for each composition of the examples and comparative examples, side sealing substrates were manufactured using the following method, and the curing state of the sealing material was evaluated and reliability tests were performed. The results are shown in Tables 1 to 3.

<Manufacturing of side sealing substrate>

A 4 mL composition was applied to a 30 mm square alkali-free glass substrate using a tabletop applicator (SHOTmini manufactured by Musashi Engineering Co., Ltd.) with a nozzle diameter of 0.2 mmφ to form a square shape of approximately 17 mm square, thereby producing a first glass substrate. Next, a glass substrate (manufactured by Q-Lights Co., Ltd.) on which metallic calcium was deposited to a thickness of 0.2 μm over a 13 mm square area was prepared as a second glass substrate, and the first and second glass substrates were bonded together. At this time, the positions of 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. Thereafter, the first glass substrate was irradiated with ultraviolet light having a wavelength of 365 nm and an irradiance of 600 mJ/cm2, and then pressed using a vacuum press at a temperature of 40°C and a load of 0.1 MPa. Next, a side-sealed substrate was obtained by sealing the side with a sealant made of a cured product of the composition by heating in an oven at 80°C for 30 minutes.

<Assessment of hardening status>

The side sealing substrate was visually inspected, and a case in which there was no uncured part in the sealing material was evaluated as A, and a case in which an uncured part was recognized in the sealing material was evaluated as C.

Reliability Test

The side sealing substrate was placed in an atmosphere of 85°C and 85% RH. The time until the black metallic calcium layer completely turned white due to the reaction with water was measured.

Claims (17)

A polymerizable compound comprising at least one selected from the group consisting of an alicyclic epoxy compound and an acyclic epoxy compound, at least one inorganic fine particle selected from the group consisting of spherical silica, spherical alumina, spherical magnesia, and spherical zirconia, and a photopolymerization initiator,
The content of the above inorganic fine particles is 30% by volume or more,
A composition having a curing depth of 100㎛ or more when filled into a urethane tube having an inner diameter of 4mm and a depth of 8mm, the sides and bottom of which are covered with aluminum foil, and irradiated with ultraviolet light at an irradiance of 600mJ/cm2 from the top of the tube on a hot plate at 80℃ using an LED light source having a wavelength of 365nm, and left to stand at 80℃ for 30 minutes. A composition according to claim 1, wherein the inorganic fine particles are inorganic fine particles having a refractive index n ₂ such that the absolute value of the difference (|n ₁ -n ₂ |) between the inorganic fine particles and the refractive index n ₁ of the polymer of the polymerizable compound is 0.5 or less. A composition according to claim 1, wherein the refractive index n ₂ of the inorganic fine particles is 1.4 or more. A composition according to claim 1, wherein the average circularity of the inorganic fine particles is 0.7 or more and 1.0 or less. A composition according to claim 1, wherein the inorganic fine particles comprise at least one selected from the group consisting of spherical silica and spherical alumina. A composition according to claim 1, wherein the sum of the total light transmittance T ₀ (%) and the total light reflectance R ₀ (%) per 100㎛ of thickness (T ₀ + R ₀ ) is 50% or more. A composition according to claim 1, wherein the photopolymerization initiator comprises a compound represented by the following chemical formula (1).
[Chemical 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.] A composition according to claim 1, further comprising a photosensitizer represented by the following formula (2).
[Chemical Formula 2]

[In formula (2), R ² represents an alkyl group that may have a substituent. Multiple R ^2s may be the same or different.] A composition according to claim 1, which is a composition for forming a cured body having a moisture permeability of 100 g/(㎡·24 hours) or less per 100 μm of thickness measured under conditions of a temperature of 85°C and a relative humidity of 85% in accordance with JIS Z0208. A composition according to claim 1, which is a composition for forming a cured body having an absorption rate of 3% or less at a temperature of 85°C, a relative humidity of 85%, and 24 hours. A composition according to claim 1, which is a sealant for an organic EL display device. A composition according to claim 1, which is a sealant for forming a dam in a dam-fill type. A polymerizable compound comprising at least one selected from the group consisting of an alicyclic epoxy compound and an acyclic epoxy compound,
At least _{one inorganic fine particle selected from the group consisting of spherical silica, spherical alumina, spherical magnesia and spherical zirconia, having a refractive index n 2 such} that the absolute value of the difference (|n ₁ -n ₂ |) between the refractive index n 1 of the polymer of the above polymerizable compound is 0.5 or less,
Contains a photopolymerization initiator,
The content of the above inorganic fine particles is 30% by volume or more,
The content of the photopolymerization initiator is 0.3 parts by mass or more with respect to 100 parts by mass of the polymerizable compound,
A composition in which the average circularity of the above-mentioned inorganic fine particles is 0.7 or more and 1.0 or less. A cured product of the composition according to any one of claims 1 to 13. Organic EL display elements,
It has a sealing structure made of a dam and a filler that seals the above organic EL display element,
An organic EL display device comprising the cured material described in claim 14. An organic EL display device, which is an organic EL television, according to claim 15. delete