JP7599145B2 - Ultraviolet-curable resin composition, optical component, method for manufacturing optical component, light-emitting device, and method for manufacturing light-emitting device - Google Patents

Description

The present invention relates to an ultraviolet-curable resin composition, an optical component, a method for manufacturing an optical component, a light-emitting device, and a method for manufacturing a light-emitting device, and more specifically to an ultraviolet-curable resin composition that can be molded by an inkjet method, an optical component made from the ultraviolet-curable resin composition, a method for manufacturing an optical component using the ultraviolet-curable resin composition, a light-emitting device including the optical component, and a method for manufacturing a light-emitting device using the ultraviolet-curable resin composition.

Light-emitting devices such as organic electroluminescence (EL) devices are used in lighting, displays, and other applications, and are expected to become more widespread in the future.

A light-emitting device is configured, for example, by placing a light-emitting element on a support substrate and placing a transparent substrate opposite the support substrate. In this case, the light emitted by the light-emitting element passes through the transparent substrate and is emitted to the outside.

When light-emitting elements such as organic EL elements deteriorate due to moisture, dark spots, which are areas that do not emit light, may appear. For this reason, the light-emitting elements are covered with a transparent sealant and a passivation layer made of a nitrogen compound to prevent moisture from entering the light-emitting elements from the outside (see Patent Document 1).

JP 2014-186850 A

In response to the trend toward thinner light-emitting devices, the inventors attempted to make the encapsulant thinner when producing the encapsulant on the passivation layer, but discovered a problem in that the thinner the encapsulant, the worse the flatness and smoothness of the encapsulant's surface became. If the flatness and smoothness of the encapsulant surface deteriorates, the light-emitting performance of the light-emitting device will deteriorate.

The object of the present invention is to provide an ultraviolet-curable resin composition that tends to produce a flat and smooth cured film when cured on an inorganic material, an optical component produced from the ultraviolet-curable resin composition, a method for producing an optical component using the ultraviolet-curable resin composition, a light-emitting device including an optical component, and a method for producing a light-emitting device using the ultraviolet-curable resin composition.

The ultraviolet-curable resin composition according to one embodiment of the present invention contains a photopolymerizable compound (A) and a photopolymerization initiator (B). The photopolymerizable compound (A) contains a water-soluble compound (C), and the percentage of the water-soluble compound (C) relative to the ultraviolet-curable resin composition is 10 mass% or more. The viscosity of the ultraviolet-curable resin composition at 25°C is 30 mPa·s or less.

An optical component according to one aspect of the present invention includes a cured product of the ultraviolet-curable resin composition.

A method for producing an optical component according to one aspect of the present invention includes molding the ultraviolet-curable resin composition by an inkjet method, and then irradiating the ultraviolet-curable resin composition with ultraviolet light to cure it.

The light-emitting device according to one aspect of the present invention includes a light source and an optical component that transmits light emitted by the light source. The optical component includes a cured product of the ultraviolet-curable resin composition.

A method for manufacturing a light-emitting device according to one aspect of the present invention is a method for manufacturing a light-emitting device including a light source and an optical component that transmits light emitted by the light source. The method includes manufacturing the optical component by the method for manufacturing the optical component.

According to one aspect of the present invention, there are obtained an ultraviolet-curable resin composition that is likely to become flat and smooth when formed into a film on an inorganic material, an optical component made from the ultraviolet-curable resin composition, a method for manufacturing an optical component using the ultraviolet-curable resin composition, a light-emitting device including an optical component, and a method for manufacturing a light-emitting device using the ultraviolet-curable resin composition.

1 is a schematic cross-sectional view showing an example of a light-emitting device according to an embodiment of the present invention.

One embodiment of the present invention is described below.

The ultraviolet-curable resin composition according to this embodiment (hereinafter also referred to as composition (X)) contains a photopolymerizable compound (A) and a photopolymerization initiator (B). The photopolymerizable compound (A) contains a water-soluble compound (C). The percentage of the water-soluble compound (C) in composition (X) is 10 mass% or more. The viscosity of composition (X) at 25°C is 30 mPa·s or less.

The water-soluble compound (C) is a compound that is photopolymerizable and water-soluble. A water-soluble compound is a compound that, when mixed with an equal volume of pure water at 20°C under 1 atmosphere to prepare a mixed liquid, and the mixed liquid is gently stirred and then allowed to stand, the mixed liquid maintains a uniform appearance even after the flow of the mixed liquid has subsided.

According to this embodiment, the affinity between the composition (X) and an inorganic material such as silicon nitride can be increased by the water-soluble compound (C), and the viscosity of the composition (X) is 30 mPa·s or less, so that the fluidity of the composition (X) can be increased. Therefore, when the composition (X) is applied onto an inorganic material such as silicon nitride to form a coating film, the surfaces of the coating film and the cured film obtained by curing this coating film tend to be flat and smooth. Therefore, when a cured film is produced from the composition (X) on an inorganic material, even if the surface of the inorganic material has irregularities and the thickness of the cured film is small, the cured film tends to be flat and smooth.

The percentage of the water-soluble compound (C) relative to the composition (X) is preferably 10% by mass or more, and even more preferably 15% by mass or more. The percentage of the water-soluble compound (C) relative to the composition (X) is preferably 50% by mass or less. In this case, outgassing due to the volatilization of the water-soluble compound (C) from the composition (X) and the cured product is suppressed. The percentage of the water-soluble compound (C) is more preferably 40% by mass or less, and even more preferably 30% by mass or less.

Optical components can be manufactured from composition (X), and light-emitting devices equipped with optical components can also be manufactured. Note that the use of composition (X) is not limited to the manufacture of optical components, and composition (X) can be used in a variety of applications that utilize the properties of composition (X).

It is preferable that the composition (X) is molded by the inkjet method. In this case, it is easy to produce a cured product of the composition (X) with good positional accuracy. In addition, compared with molding by a printing method involving contact such as a screen printing method, when the composition (X) is molded by the inkjet method, foreign matter is less likely to be mixed into the composition (X) and its cured product, and therefore the yield in manufacturing optical parts is less likely to deteriorate. In this embodiment, as described above, the viscosity of the composition (X) at 25°C is 30 mPa·s or less, so that the composition (X) is easily molded by the inkjet method. It is more preferable that this viscosity is 25 mPa·s or less, even more preferable that it is 20 mPa·s or less, and particularly preferable that it is 15 mPa·s or less. It is also preferable that this viscosity is 1 mPa·s or more, and it is also preferable that it is 5 mPa·s or more.

Such a low viscosity of composition (X) can be achieved by the composition of composition (X) described in detail below. The method and conditions for measuring the viscosity are described in detail in the Examples section below.

It is preferable that the outgassing rate generated when the cured product of composition (X) is heated at 100°C for 30 minutes is 200 ppm or less. In this case, outgassing is unlikely to occur from the cured product. Therefore, it is possible to make it difficult for gaps due to outgassing to occur in a light-emitting device equipped with an optical component containing the cured product. This makes it difficult for water and oxygen to reach the light-emitting element through the gap, making it difficult for the light-emitting element to deteriorate due to water and oxygen. It is more preferable that the outgassing rate is 100 ppm or less, and even more preferable that it is 50 ppm or less. The method and conditions for measuring the outgassing rate will be explained in detail in the Examples section below.

It is preferable that the composition (X) does not contain a solvent or the content of the solvent is 1% by mass or less. In this case, outgassing derived from the solvent is unlikely to occur from the composition (X) and the cured product of the composition (X). In addition, a drying process for removing the solvent from the composition (X) and the cured product during the production of the optical components and the light-emitting device can be eliminated. There may be a drying process for removing the solvent from at least one of the composition (X) and the cured product, but in this case, it is possible to reduce at least one of the heating temperature and the heating time in the drying process. Therefore, outgassing can be unlikely to occur from the optical components without reducing the manufacturing efficiency of the optical components and the light-emitting device. Furthermore, when the composition (X) is molded, especially by the inkjet method, the thickness is unlikely to decrease due to the evaporation of the solvent from the composition (X) after molding, and therefore the thickness of the optical components is unlikely to decrease. Therefore, the thickness of the optical components can be secured as large as possible while molding by the inkjet method. The content of the solvent is more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, and particularly preferably 0.1% by mass or less. It is particularly preferred that composition (X) does not contain a solvent or contains only a solvent that is unavoidably mixed in.

The glass transition temperature of the cured product of the composition (X) is preferably 80°C or higher. That is, the composition (X) preferably has the property of becoming a cured product with a glass transition temperature of 80°C or higher when cured. In this case, the cured product can have good heat resistance. Therefore, for example, when the cured product is subjected to a process involving a temperature increase, the cured product is less likely to deteriorate. Therefore, for example, when a layer of an inorganic material (e.g., a passivation layer 6) that overlaps an optical component is produced by a deposition method such as a plasma CVD method, the optical component is less likely to deteriorate even if the optical component is heated. In addition, by increasing the heat resistance, the optical component can be adapted to an in-vehicle application that has strict requirements for heat resistance. The glass transition temperature of the cured product is more preferably 100°C or higher, and even more preferably 120°C or higher. This glass transition temperature of the cured product can be achieved by the composition of the composition (X) described in detail below.

When 20 mg of composition (X) is heated at 100°C for 30 minutes using a thermogravimetric analyzer, the volatility is preferably 40% or less. The volatility of composition (X) is defined as the percentage of the weight loss of composition (X) after treatment (the difference between the weight of composition (X) before treatment and the weight of composition (X) after treatment) relative to the weight of composition (X) before treatment. In this case, the low volatility of composition (X) can improve the storage stability of composition (X). In addition, outgassing is less likely to occur from the cured product of composition (X) and optical components. Therefore, voids due to outgassing are even less likely to occur in the light-emitting device. The volatility of composition (X) can be determined by heating 20 mg of composition (X) at 100°C for 30 minutes using a thermogravimetric analyzer and calculating the weight loss after treatment relative to the weight before treatment. When 20 mg of composition (X) is heated at 100°C for 30 minutes using a thermogravimetric analyzer, the volatility is preferably 30% or less, and even more preferably 20% or less. The lower limit of the volatility of composition (X) is not particularly limited, but may be, for example, 0.1% or more.

The components contained in composition (X) are described in more detail below.

The photopolymerizable compound (A) is a compound that can undergo a polymerization reaction when irradiated with ultraviolet light. The photopolymerizable compound (A) contains at least one component selected from the group consisting of, for example, a monomer, an oligomer, and a prepolymer.

The photopolymerizable compound (A) contains, for example, at least one of a radically polymerizable compound (A1) and a cationic polymerizable compound (A2). When the photopolymerizable compound (A) contains a radically polymerizable compound (A1), the photopolymerization initiator (B) preferably contains a photoradical polymerization initiator (B1). When the photopolymerizable compound (A) contains a cationic polymerizable compound (A2), the photopolymerization initiator (B) preferably contains a photocationic polymerization initiator (B2) (cationic curing catalyst).

When the photopolymerizable compound (A) contains a radically polymerizable compound (A1), the radically polymerizable compound (A1) preferably contains an acrylic compound (Y). The acrylic compound (Y) has one or more (meth)acryloyl groups in one molecule.

The acrylic compound (Y) preferably contains a polyfunctional acrylic compound (Y1) having two or more radically polymerizable functional groups, including a (meth)acryloyl group, in one molecule. In this case, the polyfunctional acrylic compound (Y1) can increase the glass transition temperature of the cured product, and therefore the heat resistance of the cured product can be improved. The percentage of the polyfunctional acrylic compound (Y1) is preferably 50% by mass or more and 100% by mass or less with respect to the total acrylic compound (Y). The acrylic compound (Y) may contain only the polyfunctional acrylic compound (Y1).

The polyfunctional acrylic compound (Y1) may contain a compound (Y11) having a structure shown in the following formula (200):

CH ₂ =CR ¹ -COO-(R ³ -O)n-CO-CR ² =CH ₂ ... (200)
In formula (200), each of R ¹ and R ² is a hydrogen atom or a methyl group, n is an integer of 1 or more, and R ³ is an alkylene group having 1 or more carbon atoms. When n is 2 or more, The ^R3 may be the same or different. The percentage of the compound (Y11) relative to the acrylic compound (Y) is preferably 50% by mass or more. In this case, the affinity of the cured product for water is The percentage of the compound (Y11) relative to the acrylic compound (Y) is, for example, 100% by mass or less, or 95% by mass or less, and preferably 80% by mass or less. For example, the composition contains at least one compound selected from the group consisting of alkylene glycol di(meth)acrylate, polyalkylene glycol di(meth)acrylate, and alkylene oxide-modified alkylene glycol di(meth)acrylate.

It is particularly preferred that the polyfunctional acrylic compound (Y1) contains polyalkylene glycol di(meth)acrylate. Since polyalkylene glycol di(meth)acrylate has low viscosity and is not easily volatile, it can contribute to lowering the viscosity of the composition (X), improving the storage stability of the composition (X), and reducing outgassing from the cured product. The percentage of polyalkylene glycol di(meth)acrylate to the acrylic compound (Y) is preferably 40% by mass or more and 80% by mass or less.

The polyfunctional acrylic compound (Y1) may contain a compound having three or more radically polymerizable functional groups, including a (meth)acryloyl group, in one molecule. In this case, the polyfunctional acrylic compound (Y1) may contain at least one selected from the group consisting of, for example, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and pentaerythritol tetra(meth)acrylate. In this case, the glass transition temperature of the cured product can be particularly increased, and therefore the heat resistance of the cured product can be particularly increased. It is preferable that the polyfunctional acrylic compound (Y1) contains, in particular, pentaerythritol tetra(meth)acrylate. The percentage of pentaerythritol tetra(meth)acrylate relative to the acrylic compound (Y) is preferably 0.5% by mass or more and 10% by mass or less.

It is also preferable that the acrylic compound (Y) contains a monofunctional acrylic compound (Y2) in which the radically polymerizable functional group in one molecule is only one (meth)acryloyl group. The monofunctional acrylic compound (Y2) can suppress shrinkage during curing of the composition (X). The amount of the monofunctional acrylic compound (Y2) relative to the total amount of the acrylic compound (Y) is preferably more than 0 mass% and not more than 50 mass%.

Examples of the monofunctional acrylic compound (Y2) include tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, 3-methoxybutyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydixylethyl acrylate, ethyl diglycol acrylate, cyclic triacrylate, ethyl ... trimethylolpropane formal monoacrylate, imide acrylate, isoamyl acrylate, ethoxylated succinic acid acrylate, trifluoroethyl acrylate, ω-carboxypolycaprolactone monoacrylate, cyclohexyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, stearyl acrylate, diethylene glycol monobutyl ether acrylate, lauryl acrylate, isodecyl acrylate, 3,3,5-trimethylcyclohexanol acrylate, isooctyl acrylate, octyl/decyl acrylate, tridecyl acrylate, caprolactone acrylate acrylate, ethoxylated (4) nonylphenol acrylate, methoxypolyethylene glycol (350) monoacrylate, methoxypolyethylene glycol (550) monoacrylate, phenoxyethyl acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl acrylate, methylphenoxyethyl acrylate, 4-t-butylcyclohexyl acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, tribromophenyl acrylate, ethoxylated tribromophenyl acrylate, 2-furfuryl acrylate, It contains at least one compound selected from the group consisting of phenoxyethyl acrylate, ethylene oxide adduct of 2-phenoxyethyl acrylate, propylene oxide adduct of 2-phenoxyethyl acrylate, acryloylmorpholine, morpholin-4-yl acrylate, dicyclopentanyl acrylate, phenoxydiethylene glycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 1,4-cyclohexanedimethanol monoacrylate, 3-methacryloyloxymethylcyclohexene oxide, and 3-acryloyloxymethylcyclohexene oxide.

The acrylic compound (Y) may contain a compound represented by the following formula (100). In this case, the reactivity of the composition (X) can be increased, and the adhesion between the cured product and the inorganic material can be improved.

In formula (100), R ⁰ is H or a methyl group. X is a single bond or a divalent hydrocarbon group. Each of R ¹ to R ¹¹ is H, an alkyl group or -R ¹² -OH, R ¹² is an alkylene group, and at least one of R ¹ to R ¹¹ is an alkyl group or -R ¹² -OH. R ¹ to R ¹¹ are not chemically bonded to each other.

The radically polymerizable compound (A1) may contain a radically polymerizable compound (Z) other than the acrylic compound (Y). The amount of the radically polymerizable compound (Z) relative to the total amount of the acrylic compound (Y) and the polymerizable compound (Z) is, for example, 10 mass% or less.

When the photopolymerizable compound (A) contains a radically polymerizable compound (A1), the radically polymerizable compound (A1) may contain a radically polymerizable water-soluble compound (C1) which is at least a part of the water-soluble compound (C). The water-soluble compound (C1) includes at least one selected from the group consisting of, for example, HO-250(N), 130MA, EG, and HOA(N) of the Light Ester Series manufactured by Kyoeisha Chemical Co., Ltd., 130A and 3EG-A of the Light Acrylate Series, and methacrylic acid manufactured by Mitsubishi Chemical Corporation.

The photoradical polymerization initiator (B1) is not particularly limited as long as it is a compound that generates radical species when irradiated with ultraviolet light. The photoradical polymerization initiator (B1) contains at least one compound selected from the group consisting of, for example, aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, oxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds.

The percentage of the photoradical polymerization initiator (B1) relative to the radically polymerizable compound (A1) is preferably 6% by mass or more. This percentage is more preferably 7% by mass or more, and even more preferably 8% by mass or more. This percentage is, for example, 30% by mass or less, preferably 20% by mass or less, and even more preferably 18% by mass or less.

The photoradical polymerization initiator (B1) may contain a sensitizer as part of the photoradical polymerization initiator (B1). The sensitizer may contain at least one compound selected from the group consisting of, for example, 9,10-dibutoxyanthracene, 9-hydroxymethylanthracene, thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, anthraquinone, 1,2-dihydroxyanthraquinone, 2-ethylanthraquinone, 1,4-diethoxynaphthalene, p-dimethylaminoacetophenone, p-diethylaminoacetophenone, p-dimethylaminobenzophenone, p-diethylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, p-dimethylaminobenzaldehyde, and p-diethylaminobenzaldehyde. However, the components that the sensitizer may contain are not limited to those mentioned above. The content of the sensitizer in composition (X) is, for example, 0.1 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the solid content of composition (X).

The composition (X) may contain a polymerization accelerator in addition to the photoradical polymerization initiator (B1). The polymerization accelerator contains, for example, an amine compound such as ethyl p-dimethylaminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, methyl p-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, or butoxyethyl p-dimethylaminobenzoate. Note that the components that the polymerization accelerator may contain are not limited to those mentioned above.

When the photopolymerizable compound (A) contains a cationic polymerizable compound (A2), the cationic polymerizable compound (A2) contains, for example, at least one of a polyfunctional cationic polymerizable compound (W1) and a monofunctional cationic polymerizable compound (W2).

The polyfunctional cationic polymerizable compound (W1) can contain either or both of a polyfunctional cationic polymerizable compound (W11) that does not have a siloxane skeleton and a polyfunctional cationic polymerizable compound (W12) that has a siloxane skeleton.

The polyfunctional cationic polymerizable compound (W11) does not have a siloxane skeleton and has two or more cationic polymerizable functional groups per molecule. The number of cationic polymerizable functional groups per molecule of the polyfunctional cationic polymerizable compound (W11) is preferably 2 to 4, and more preferably 2 to 3.

The cationic polymerizable functional group is, for example, at least one group selected from the group consisting of a cyclic ether group and a vinyl ether group. The cyclic ether group is, for example, at least one of an epoxy group and an oxetane group.

The polyfunctional cationic polymerizable compound (W11) contains at least one compound selected from the group consisting of, for example, polyfunctional alicyclic epoxy compounds, polyfunctional heterocyclic epoxy compounds, polyfunctional oxetane compounds, alkylene glycol diglycidyl ethers, and alkylene glycol monovinyl monoglycidyl ethers.

The polyfunctional alicyclic epoxy compound contains, for example, one or both of the compounds shown in the following formula (1) and the compounds shown in the following formula (20).

In formula (1), each of R ¹ to R ¹⁸ is independently a hydrogen atom, a halogen atom, or a hydrocarbon group. The number of carbon atoms in the hydrocarbon group is preferably within the range of 1 to 20. The hydrocarbon group is, for example, an alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, or a propyl group; an alkenyl group having 2 to 20 carbon atoms, such as a vinyl group or an allyl group; or an alkylidene group having 2 to 20 carbon atoms, such as an ethylidene group or a propylidene group. The hydrocarbon group may contain an oxygen atom or a halogen atom. Each of R ¹ to R ¹⁸ is independently preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

In formula (1), X is a single bond or a divalent organic group, and the organic group is, for example, --CO--O--CH ₂ --.

Examples of the compound represented by formula (1) include the compound represented by formula (1a) below and the compound represented by formula (1b) below.

In formula (20), each of R ¹ to R ¹² is independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms. The halogen atom is, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. The hydrocarbon group having 1 to 20 carbon atoms is, for example, an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, or a propyl group; an alkenyl group having 2 to 20 carbon atoms such as a vinyl group or an allyl group; or an alkylidene group having 2 to 20 carbon atoms such as an ethylidene group or a propylidene group. The hydrocarbon group having 1 to 20 carbon atoms may contain an oxygen atom or a halogen atom.

Each of R ¹ to R ¹² independently is preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

An example of the compound represented by formula (20) includes the tetrahydroindene diepoxide represented by the following formula (20a):

The polyfunctional heterocyclic epoxy compound contains, for example, a trifunctional epoxy compound as shown in the following formula (2).

The polyfunctional oxetane compound contains, for example, a bifunctional oxetane compound as shown in the following formula (3).

The alkylene glycol diglycidyl ether contains at least one compound selected from the group consisting of compounds represented by the following formulas (4) to (7).

The alkylene glycol monovinyl monoglycidyl ether contains, for example, the compound shown in formula (8) below.

More specifically, the polyfunctional cationic polymerizable compound (W11) can contain at least one component selected from the group consisting of, for example, CELLOXIDE 2021P and CELLOXIDE 8010 manufactured by Daicel, TEPIC-VL manufactured by Nissan Chemical, OXT-221 manufactured by Toagosei, and 1,3-PD-DEP, 1,4-BG-DEP, 1,6-HD-DEP, NPG-DEP, and butylene glycol monovinyl monoglycidyl ether manufactured by Yokkaichi Chemical.

It is also preferable that the polyfunctional cationically polymerizable compound (W11) contains a polyfunctional alicyclic epoxy compound. In this case, the composition (X) can have particularly high cationic polymerization reactivity.

It is particularly preferable that the polyfunctional alicyclic epoxy compound contains either one or both of the compounds shown in formula (1) and the compounds shown in formula (20). In this case, composition (X) can have higher cationic polymerization reactivity.

When the polyfunctional alicyclic epoxy compound contains a compound represented by formula (1), the compound represented by formula (1) preferably contains a compound represented by formula (1a). In this case, composition (X) can have a higher cationic polymerization reactivity and a particularly low viscosity.

In addition, since the compound shown in formula (20) has a low viscosity, when the compound shown in formula (20) is contained, the composition (X) can have good ultraviolet curing properties and a particularly low viscosity. Furthermore, the compound shown in formula (20) has a low viscosity but is difficult to volatilize. Therefore, even if the composition (X) contains the compound shown in formula (20), the composition (X) is unlikely to undergo a change in composition due to the volatilization of the compound shown in formula (20). Therefore, by containing the compound shown in formula (20), the viscosity of the composition (X) can be reduced without impairing storage stability.

The compound shown in formula (20) can be synthesized, for example, by oxidizing a cyclic olefin compound having a tetrahydroindene skeleton using an oxidizing agent.

The compound shown in formula (20) may contain four stereoisomers based on the stereoconfiguration of the two epoxy rings. The compound shown in formula (20) may contain any of the four stereoisomers. That is, the compound shown in formula (20) may contain at least one component selected from the group consisting of the four stereoisomers. In the compound shown in formula (20), the total percentage of the exo-endo isomer and the endo-endo isomer among the four stereoisomers is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total epoxy compound (A1). In this case, the heat resistance of the cured product can be improved. The percentage of a specific stereoisomer in the compound shown in formula (20) can be determined based on the peak area ratio appearing in a chromatogram obtained by gas chromatography.

In order to reduce the amount of exo-endo and endo-endo isomers in the compound represented by formula (20), appropriate methods can be applied, such as a method of subjecting the compound represented by formula (20) to precision distillation or a method of applying column chromatography using silica gel or the like as a packing material.

When the composition (X) contains a polyfunctional cationic polymerizable compound (W11), the percentage of the polyfunctional cationic polymerizable compound (W11) relative to the total amount of the resin components is preferably 5% by mass or more and 95% by mass or less. The resin components refer to compounds having cationic polymerizability in the composition (X), and include the polyfunctional cationic polymerizable compound (W1) and the monofunctional cationic polymerizable compound (W2). If the percentage of the polyfunctional cationic polymerizable compound (W11) is 5% by mass or more, the composition (X) can have particularly excellent reactivity during the photocationic polymerization reaction, and the cured product can have high strength (hardness). In addition, if the percentage of the polyfunctional cationic polymerizable compound (W11) is 95% by mass or less, when the composition (X) contains a moisture absorbent (D), the moisture absorbent (D) can be easily dispersed particularly uniformly in the composition (X). The percentage of this polyfunctional cationic polymerizable compound (W11) is more preferably 12% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, and particularly preferably 25% by mass or more. The percentage of this polyfunctional cationic polymerizable compound (W11) is more preferably 85% by mass or less, and even more preferably 60% by mass or less. For example, the percentage of the polyfunctional cationic polymerizable compound (W11) is preferably within the range of 20 to 60% by mass.

When the polyfunctional cationic polymerizable compound (W11) contains a polyfunctional alicyclic epoxy compound, the polyfunctional alicyclic epoxy compound may be a part or the whole of the polyfunctional cationic polymerizable compound (W11). The percentage of the polyfunctional alicyclic epoxy compound relative to the polyfunctional cationic polymerizable compound (W11) is preferably 15% by mass or more and 100% by mass or less. When this percentage is 15% by mass or more, the polyfunctional alicyclic epoxy compound can particularly contribute to improving the ultraviolet curing property of the composition (X).

The polyfunctional cationic polymerizable compound (W12) has a siloxane skeleton and two or more cationic polymerizable functional groups per molecule. The number of cationic polymerizable functional groups per molecule of the polyfunctional cationic polymerizable compound (W12) is preferably 2 to 6, more preferably 2 to 4. The polyfunctional cationic polymerizable compound (W12) can contribute to improving the cationic polymerization reactivity of the composition (X) and can also contribute to improving the heat discoloration resistance of the cured product and optical components. The polyfunctional cationic polymerizable compound (W12) can also contribute to lowering the elastic modulus of the cured product and optical components. When the composition (X) contains a moisture absorbent, the polyfunctional cationic polymerizable compound (W12) can also contribute to improving the dispersibility of the moisture absorbent in the composition (X) and the cured product.

It is preferable that the polyfunctional cationic polymerizable compound (W12) is liquid at 25°C. In particular, it is preferable that the viscosity of the polyfunctional cationic polymerizable compound (W12) at 25°C is in the range of 10 to 300 mPa·s. In this case, the increase in viscosity of the composition (X) can be suppressed.

The cationically polymerizable functional group possessed by the polyfunctional cationically polymerizable compound (W12) is, for example, at least one group selected from the group consisting of an epoxy group, an oxetane group, and a vinyl ether group.

The siloxane skeleton of the polyfunctional cationically polymerizable compound (W12) may be linear, branched, or cyclic. The number of Si atoms in the siloxane skeleton is preferably within the range of 2 to 14. In this case, the composition (X) can have a particularly low viscosity. The number of Si atoms is more preferably within the range of 2 to 10, even more preferably within the range of 2 to 7, and particularly preferably within the range of 3 to 6.

The polyfunctional cationic polymerizable compound (W12) contains, for example, at least one of a compound shown in formula (10) and a compound shown in formula (11).

In each of formulas (10) and (11), R is a single bond or a divalent organic group, and is preferably an alkylene group. Y is a siloxane skeleton, which may be linear, branched, or cyclic, and the number of Si atoms is preferably within the range of 2 to 14, more preferably within the range of 2 to 10, even more preferably within the range of 2 to 7, and particularly preferably within the range of 3 to 6. n is an integer of 2 or more, and is preferably within the range of 2 to 4.

More specifically, for example, the polyfunctional cationic polymerizable compound (W12) contains a compound shown in the following formula (10a):

In formula (10a), R is a single bond or a divalent organic group, and is preferably an alkylene group having 1 to 4 carbon atoms. In formula (10a), n is an integer of 0 or more. n is preferably in the range of 0 to 12, more preferably in the range of 0 to 8, even more preferably in the range of 0 to 5, and particularly preferably in the range of 1 to 4.

The compound represented by formula (10a) preferably contains a compound represented by the following formula (30). In other words, the polyfunctional cationic polymerizable compound (W12) preferably contains a compound represented by the following formula (30).

More specifically, the polyfunctional cationic polymerizable compound (W12) preferably contains at least one component selected from the group consisting of, for example, product numbers X-40-2669, X-40-2670, X-40-2715, X-40-2732, X-22-169AS, X-22-169B, X-22-2046, X-22-343, X-22-163, and X-22-163B manufactured by Shin-Etsu Chemical Co., Ltd.

The polyfunctional cationic polymerizable compound (W12) preferably has an alicyclic epoxy structure, and it is particularly preferred if the polyfunctional cationic polymerizable compound (W12) contains a compound represented by formula (10a). The compound represented by formula (10a) can particularly contribute to improving the cationic polymerization reactivity and reducing the viscosity of the composition (X), and can also particularly contribute to improving the heat discoloration resistance and reducing the elastic modulus of the cured product and optical components. When the composition (X) contains a moisture absorbent (D), it can also particularly contribute to improving the dispersibility of the moisture absorbent (D) in the composition (X).

When the composition (X) contains a polyfunctional cationic polymerizable compound (W12), the percentage of the polyfunctional cationic polymerizable compound (W12) relative to the total amount of the resin components is preferably 5% by mass or more and 95% by mass or less. In this case, when the composition (X) contains a moisture absorbent (D), the dispersibility of the moisture absorbent (D) in the composition (X) and in the cured product is particularly improved, and the composition (X) can have a particularly high photocationic polymerization reactivity.

The monofunctional cationically polymerizable compound (W2) has only one cationically polymerizable functional group per molecule. The cationically polymerizable functional group is, for example, at least one group selected from the group consisting of an epoxy group, an oxetane group, and a vinyl ether group.

The viscosity of the monofunctional cationic polymerizable compound (W2) at 25°C is preferably 8 mPa·s or less. In this case, even if the composition (X) does not contain a solvent, the monofunctional cationic polymerizable compound (W2) can reduce the viscosity of the composition (X). In particular, the viscosity of the monofunctional cationic polymerizable compound (W2) at 25°C is preferably within the range of 0.1 to 8 mPa·s.

The monofunctional cationic polymerizable compound (W2) may contain, for example, at least one compound selected from the group consisting of the compounds shown in the following formulas (12) to (17) and limonene oxide.

The percentage of the monofunctional cationic polymerizable compound (W2) relative to the total amount of the resin components is preferably 5% by mass or more and 50% by mass or less. If the percentage of the monofunctional cationic polymerizable compound (W2) is 5% by mass or more, the viscosity of the composition (X) can be particularly reduced. Furthermore, if the percentage of the monofunctional cationic polymerizable compound (W2) is 50% by mass or less, the composition (X) can have particularly excellent reactivity during the photocationic polymerization reaction, and the cured product can have high strength (hardness). The percentage of this monofunctional cationic polymerizable compound (W2) is more preferably 10% by mass or more, and even more preferably 15% by mass or more. Furthermore, the percentage of this monofunctional cationic polymerizable compound (W2) is more preferably 40% by mass or less, even more preferably 35% by mass or less, and particularly preferably 30% by mass or less. If the percentage of the monofunctional cationic polymerizable compound (W2) is particularly 35% by mass or less, the amount of volatilization of the components in the composition (X) during storage of the composition (X) can be effectively reduced, and therefore the properties of the composition (X) are less likely to be impaired even if the composition (X) is stored for a long period of time. Furthermore, the occurrence of tack in the cured product can be particularly suppressed. For example, it is preferable that the percentage of the monofunctional cationic polymerizable compound (W2) is within the range of 10 to 35% by mass.

In particular, when the composition (X) contains a polyfunctional cationic polymerizable compound (W11) and a polyfunctional cationic polymerizable compound (W12), the percentage of the polyfunctional cationic polymerizable compound (W11) is preferably 30% by mass or more and 60% by mass or less, the percentage of the polyfunctional cationic polymerizable compound (W12) is preferably 15% by mass or more and 30% by mass or less, and the percentage of the monofunctional cationic polymerizable compound (W2) is preferably 15% by mass or more and 40% by mass or less, based on the total amount of the resin components. In this case, the composition (X) can achieve a good balance of good storage stability, low viscosity, and good cationic polymerization reactivity, and further achieve a good balance of excellent transparency, excellent moisture absorption, and high refractive index of the cured product.

If the cationic polymerizable compound (A2) contains a compound shown in formula (3) and a compound shown in formula (16), by adjusting the ratio of the two, it is possible to appropriately adjust the ease with which the curing reaction proceeds when preparing a photocured product from composition (X), while achieving a low viscosity and improved storage stability of composition (X).

The amount of the compound shown in formula (16) is appropriately adjusted so that composition (X) has the above-mentioned properties. For example, the amount of the compound shown in formula (16) is preferably 10% by mass or more and 40% by mass or less with respect to the total amount of the resin components.

The cationic polymerizable compound (A2) preferably contains a compound (f1) represented by the following formula (30) (hereinafter also referred to as aromatic epoxy compound (f1)).

In formula (30), X is at least one selected from the group consisting of halogen, H, a hydrocarbon group, and an alkylene glycol group, and when there are multiple Xs in one molecule, they may be the same or different. The hydrocarbon group is, for example, an alkyl group or an aryl group. When X is a hydrocarbon group, the number of carbon atoms of X is, for example, in the range of 1 to 10. R is a single bond or a divalent organic group. When R is a divalent organic group, the divalent organic group is, for example, an alkylene group, an oxyalkylene group, a carbonyloxyalkylene group (for example, -CO-O-CH ₂ -), or a -C(Ph) ₂ -O-CH ₂ - group. Y is H or a monovalent organic group. When Y is a monovalent organic group, the monovalent organic group is, for example, an alkyl group or an aryl group.

When the cationic polymerizable compound (A2) contains an aromatic epoxy compound (f1), the aromatic epoxy compound (f1) has a low viscosity, so that the aromatic epoxy compound (f1) tends to reduce the viscosity of the composition (X). In addition, the aromatic epoxy compound (f1) is not easily volatilized, so that even if the composition (X) is stored, the composition (X) is not easily changed in composition due to the volatilization of the aromatic epoxy compound (f1). Therefore, the aromatic epoxy compound (f1) tends to increase the storage stability of the composition (X). In addition, since the aromatic epoxy compound (f1) has high reactivity, unreacted components are not easily left in the cured product, so that outgassing is not easily generated from the cured product. Furthermore, the aromatic epoxy compound (f1) tends to increase the glass transition temperature of the cured product, so that the heat resistance of the cured product is easily increased.

In addition, the aromatic epoxy compound (f1) is less likely to produce defective droplets called satellites when the composition (X) is ejected by an inkjet method.

It is preferable that R in formula (30) is a single bond or an alkylene group. When n in formula (30) is 2 or 3, it is preferable that at least one of the multiple R in formula (30) is a single bond or an alkylene group. In these cases, the reactivity of the aromatic epoxy compound (f1) tends to be high, and therefore the curability of composition (X) tends to be high when composition (X) is irradiated with ultraviolet light.

The aromatic epoxy compound (f1) preferably contains at least one compound selected from the group consisting of the compounds represented by the following formulas (301) to (318):

In particular, it is preferable that the aromatic epoxy compound (f1) contains at least one component selected from the group consisting of the compounds represented by the formulas (301) to (305), (312), (314) and (318). These compounds tend to have high reactivity because at least one epoxy group (oxirane) in the compound is bonded to a benzene ring via a single bond or an alkylene group, and therefore tend to enhance the curability of the composition (X).

The percentage of the aromatic epoxy compound (f1) relative to the total amount of the cationic polymerizable compound (A2) is preferably 5% by mass or more. In this case, the above-mentioned effect of the aromatic epoxy compound (f1) is particularly likely to be obtained. This percentage is also preferably 95% by mass or less. In this case, the storage properties of the composition (X) tend to be good. This percentage is more preferably 10% by mass or more and 90% by mass or less, and even more preferably 20% by mass or more and 85% by mass or less.

The cationic polymerizable compound (A2) may contain a compound (f2) having an oxyalkylene skeleton. The oxyalkylene skeleton is a linear skeleton consisting of one or more linear oxyalkylene units.

When the cationic polymerizable compound (A2) contains the compound (f2), the compound (f2) has a low viscosity, and therefore the compound (f2) tends to reduce the viscosity of the composition (X). In addition, the compound (f2) is not easily volatilized, and therefore, even when the composition (X) is stored, the composition (X) is not easily changed in composition due to the volatilization of the aromatic epoxy compound (f1). Therefore, the compound (f2) tends to increase the storage stability of the composition (X).

In addition, compound (f2) is less likely to produce defective droplets called satellites when composition (X) is discharged by the inkjet method. Furthermore, compound (f2) can make it difficult for satellites to be produced even if the speed of droplets discharged by the inkjet method is increased. Therefore, although it depends on the inkjet conditions, it is possible to make the discharge speed of droplets by the inkjet method 4 m/s or more without producing satellites, for example. If the droplet speed can be increased, the trajectory of the droplets is less susceptible to disturbances, so that the dimensional accuracy of the cured product produced from composition (X) can be improved. Furthermore, compound (f2) can increase the storage stability of composition (X) as described above, so that the characteristic of composition (X) of being less likely to produce satellites is easily maintained even if composition (X) is stored for a long period of time.

It is particularly preferable that the oxyalkylene skeleton contains a structure of "-C-C-O-", i.e., an oxymethylene unit. In this case, satellites are particularly unlikely to occur, and even if the driving frequency is changed when ejecting composition (X) by an inkjet method, satellites are unlikely to occur. In addition, compound (f2) is less likely to volatilize and is more likely to have a lower viscosity, and furthermore, the affinity (wettability) of composition (X) to inorganic materials is likely to be increased.

The number of oxyalkylene units in the oxyalkylene skeleton of compound (f2) is preferably 1 or more and 8 or less. In this case, compound (f2) tends to have a lower viscosity, making it particularly unlikely for satellites to form, and the crosslink density of the cured product tends to be high, making the glass transition temperature of the cured product particularly high. The number of oxyalkylene units is more preferably 1 or more and 6 or less, and even more preferably 1 or more and 4 or less.

In addition, the oxyalkylene unit in the oxyalkylene skeleton of compound (f2) may have a substituent other than hydrogen bonded thereto. For example, the oxymethylene unit contained in the oxyalkylene skeleton may have the structure "-CH(CH ₃ )-CH ₂ -O-".

The percentage of compound (f2) is preferably 10% by mass or more relative to the cationically polymerizable compound (A2). In this case, the inkjet properties are good and the wettability to the substrate is good. It is also preferable that this percentage is 70% by mass or less. In this case, the glass transition temperature can be sufficiently increased. This percentage is more preferably 15% by mass or more and 60% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less.

Compound (f2) contains at least one compound selected from, for example, compound (f21) having an oxyalkylene skeleton and an epoxy group, and compound (f22) having an oxyalkylene group and an oxetane group.

Compound (f21) contains at least one compound selected from the group consisting of the compound shown in formula (1b), the compound shown in formula (4), the compound shown in formula (5), the compound shown in formula (6), the compound shown in formula (7), the compound shown in formula (8), the compound shown in formula (13), and the compound shown in formula (14). Note that the components that compound (f21) can contain are not limited to the above.

Compound (f22) contains at least one compound selected from the group consisting of compounds shown in formula (3), compounds shown in formula (12), compounds shown in formula (16), and compounds shown in formula (17). Note that the components that compound (f22) may contain are not limited to the above.

The cationic polymerizable compound (A2) preferably contains a cyclic ether compound. The epoxy compound contains at least one compound that has a cyclic ether group among the compounds that can be contained in the cationic polymerizable compound (A2) described above.

The cyclic ether compound contains, for example, at least one of an epoxy compound and an oxetane compound. The epoxy compound contains, for example, at least one compound among the compounds having an epoxy group among the compounds that can be included in the above-mentioned cationic polymerizable compound (A2). The oxetane compound contains, for example, at least one compound among the compounds having an oxetane group among the compounds that can be included in the above-mentioned cationic polymerizable compound (A2).

When the cyclic ether compound contains an epoxy compound, the curing reaction is likely to proceed quickly when the composition (X) is irradiated with ultraviolet light, and the curability of the composition (X) is likely to be increased. The percentage of the epoxy compound relative to the total amount of the cationic polymerizable compound (A2) is preferably 20% by mass or more. In addition, the percentage of this epoxy compound is preferably 60% by mass or less.

In addition, when the cyclic ether compound contains an oxetane compound, the rapid progress of the reaction when the composition (X) is irradiated with ultraviolet light can be suppressed, making the cured product less likely to turn yellow or become cloudy, and the reaction can be allowed to proceed sufficiently to make it less likely that outgas will be generated from the cured product. The percentage of the oxetane compound relative to the total amount of the cationically polymerizable compound (A2) is preferably 40% by mass or more. In addition, this percentage is preferably 80% by mass or less.

When the composition (X) contains a cyclic ether compound, the cyclic ether compound may contain a water-soluble compound (C2) having a cyclic ether group that is at least a part of the water-soluble compound (C). The cyclic ether compound is inherently likely to impair the affinity between the composition (X) and the inorganic material, and therefore likely to impair the flatness and smoothness of the coating film and the cured product formed on the inorganic material. However, when the cyclic ether compound contains the water-soluble compound (C2), the surfaces of the coating film and the cured product tend to be flat and smooth even if the composition (X) contains a cyclic ether compound. The water-soluble compound (C2) contains, for example, at least one of a water-soluble epoxy compound (C21) and a water-soluble oxetane compound (C22).

The water-soluble epoxy compound (C21) includes at least one selected from the group consisting of, for example, EX-145, EX-171, EX-810, and EX-920 manufactured by Nagase ChemteX Corporation, SR-PG, SR-EGM, and SR-2EG manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., A-EP, DY-BP, and Epogosey BD (D) manufactured by Yokkaichi Synthetic Co., Ltd., and Epolight 40E, Epolight 100E, Epolight 200E, and Epolight 400E manufactured by Kyoeisha Chemical Co., Ltd.

The water-soluble oxetane compound (C22) includes at least one selected from the group consisting of, for example, OXT-101 manufactured by Toa Gosei Co., Ltd., EXO and HBOX manufactured by Ube Industries, Ltd., and AL-OX manufactured by Yokkaichi Gosei Co., Ltd.

When the composition (X) contains the cationic polymerizable compound (A2), it is preferable that the composition (X) further contains a sensitizer. In this case, the composition (X) can have particularly high cationic polymerization reactivity. The sensitizer contains, for example, either one or both of 9,10-dibutoxyanthracene and 9,10-diethoxyanthracene. The percentage of the sensitizer relative to the cationic polymerizable compound (A2) is preferably in the range of more than 0 mass% and not more than 1 mass%. In this case, the sensitizer is less likely to inhibit the transparency of the cured product, and therefore the cured product can have good transparency.

When the composition (X) contains a cationic polymerizable compound (A2), the photopolymerization initiator (B) preferably contains a cationic photopolymerization initiator (B2). The cationic photopolymerization initiator (B2) is not particularly limited as long as it is a catalyst that generates a protonic acid or a Lewis acid upon irradiation with light. The cationic photopolymerization initiator (B2) can contain at least one of an ionic photoacid-generating cationic curing catalyst and a nonionic photoacid-generating cationic curing catalyst.

The ionic photoacid generating cationic curing catalyst can contain at least one of onium salts and organometallic complexes. Examples of onium salts include aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts. Examples of organometallic complexes include iron-arene complexes, titanocene complexes, and arylsilanol-aluminum complexes. The ionic photoacid generating cationic curing catalyst can contain at least one of these components.

The non-ionic photoacid generating cationic curing catalyst may contain at least one component selected from the group consisting of, for example, nitrobenzyl esters, sulfonic acid derivatives, phosphate esters, phenolsulfonic acid esters, diazonaphthoquinones, and N-hydroxyimide phosphonates. Note that the components that the non-ionic photoacid generating cationic curing catalyst may contain are not limited to the above.

More specific examples of the compound that can contain the photocationic polymerization initiator (B2) include Midori Chemical's DPI series (105, 106, 109, 201, etc.), BI-105, MPI series (103, 105, 106, 109, etc.), BBI series (101, 102, 103, 105, 106, 109, 110, 200, 210, 300, 301, etc.), TSP series (102, 103, 105, 106, 109, 200, 300, 1000, etc.), HDS-109, MDS series (103, 105, 109, 203, 205, 209, etc.), BDS-109, MNPS-109, and DTS series (102, 103, 105 , 200, etc.), NDS series (103, 105, 155, 165, etc.), DAM series (101, 102, 103, 105, 201, etc.), SI series (105, 106, etc.), PI-106, NDI series (105, 106, 109, 1001, 1004, etc.), PAI series (01, 101, 106, 1001, 1002, 1003, 1004, etc.), MBZ-101, PYR-100, NB series (101, 201, etc.), NAI series (100, 1002, 1003, 1004, 101, 105, 106, 109, etc.), TAZ series (100, 101, 102, 103, 104, 107, 10
8, 109, 110, 113, 114, 118, 122, 123, 203, 204, etc.), NBC-101, ANC-101, TPS-Acetate, DTS-Acetate, Di-Boc Bisphinol A, tert-Butyl lithocholate, tert-Butyl deoxycholate, tert-Butyl cholate, BX, BC-2, MPI-103, BDS-105, TPS-103, NAT-103, BMS-105, and TMS-105;
Cyracure UVI-6970, Cyracure UVI-6974, Cyracure UVI-6990, and Cyracure UVI-950 manufactured by Union Carbide Corporation, USA;
Irgacure 250, Irgacure 261, and Irgacure 264 manufactured by BASF;
Ciba-Geigy CG-24-61;
ADEKA OPTOMER SP-150, ADEKA OPTOMER SP-151, ADEKA OPTOMER SP-170, and ADEKA OPTOMER SP-171 manufactured by ADEKA Corporation;
DAICAT II manufactured by Daicel Corporation;
UVAC1590 and UVAC1591 manufactured by Daicel-Cytec Co., Ltd.;
CI-2064, CI-2639, CI-2624, CI-2481, CI-2734, CI-2855, CI-2823, CI-2758, and CIT-1682 manufactured by Nippon Soda Co., Ltd.;
PI-2074, tetrakis(pentafluorophenyl)borate toluylcumyl iodonium salt from Rhodia;
FFC509 manufactured by 3M;
CD-1010, CD-1011 and CD-1012 manufactured by Sartomer Corporation, USA;
CPI-100P, CPI-101A, CPI-110P, CPI-110A, and CPI-210S manufactured by San-Apro Ltd., and UVI-6992 and UVI-6976 manufactured by The Dow Chemical Company. The photocationic polymerization initiator (B2) can contain at least one compound selected from the group consisting of these compounds.

The percentage of the photocationic polymerization initiator (B2) relative to the cationic polymerizable compound (A2) is preferably 1% by mass or more and 4% by mass or less. When this percentage is 1% by mass or more, the composition (X) can have particularly good cationic polymerization reactivity. Furthermore, when this percentage is 4% by mass or less, the composition (X) can have good storage stability, and since it does not contain an excess of the photocationic polymerization initiator (B2), it is possible to reduce production costs.

The composition (X) may further contain a moisture absorbent (D). When the composition (X) contains the moisture absorbent (D), the cured product of the composition (X) can have moisture absorption properties. Therefore, the encapsulant 5 containing the cured product can further prevent moisture from penetrating into the light emitting element 4 in the light emitting device 1. The average particle size of the moisture absorbent (D) is preferably 200 nm or less. In this case, the cured product can have high transparency.

The moisture absorbent (D) is preferably an inorganic particle having moisture absorbing properties, and preferably contains at least one component selected from the group consisting of zeolite particles, silica gel particles, calcium chloride particles, and titanium oxide nanotube particles. It is particularly preferable that the moisture absorbent (D) contains zeolite particles.

Zeolite particles with an average particle size of 200 nm or less can be produced, for example, by crushing general industrial zeolite. When producing zeolite particles, the zeolite may be crushed and then crystallized by hydrothermal synthesis or the like, in which case the zeolite particles can have particularly high hygroscopicity. Examples of methods for producing such zeolite particles are disclosed in JP 2016-69266 A, JP 2013-049602 A, and the like.

The zeolite particles preferably contain sodium ions. For this reason, the zeolite particles are preferably made from at least one type selected from the group consisting of A-type zeolite, X-type zeolite, and Y-type zeolite. It is particularly preferable that the zeolite particles are made from 4A-type zeolite among A-type zeolites. In these cases, the zeolite particles have a crystal structure suitable for adsorbing moisture.

The pH of the zeolite particles is preferably 7 or more and 10 or less. When the pH of the zeolite particles is 7 or more, the crystals of the zeolite particles are less likely to be destroyed, and therefore the cured product of the composition (X) containing the zeolite particles can have particularly high moisture absorption. When the pH of the zeolite particles is 10 or less, the zeolite particles are less likely to inhibit the curing of the composition (X) when it is cured. The pH of the zeolite particles is a value obtained by heating a dispersion obtained by adding 0.05 g of zeolite particles to 99.95 g of ion-exchanged water at 90°C for 24 hours, and then measuring the pH of the supernatant of the dispersion with a pH meter. As the pH meter, for example, a compact pH meter <LAQUAtwin> B-711 manufactured by Horiba, Ltd. can be used.

The average particle size of the moisture absorbent (D) is preferably 10 nm or more and 200 nm or less. If the average particle size is 200 nm or less, the cured product can have particularly high transparency. If the average particle size is 10 nm or more, the moisture absorbent (D) can maintain good moisture absorption. Note that this average particle size is the median diameter calculated from the measurement results by dynamic light scattering, that is, the cumulative 50% diameter (D50). Note that the Nanotrac Wave series from Microtrac Bell Co., Ltd. can be used as a measuring device.

The average particle size of the moisture absorbent (D) is preferably 150 nm or less, more preferably 100 nm or less, and particularly preferably 70 nm or less. The average particle size of the moisture absorbent (D) is preferably 20 nm or more, and more preferably 50 nm or more. In this case, the cured product can have particularly good transparency and moisture absorption.

It is also preferable that the cumulative 90% diameter (D90) of the moisture absorbent (D) is 100 nm or less. In this case, the cured product can have particularly high transparency.

When the composition (X) contains the moisture absorbent (D), the percentage of the moisture absorbent (D) relative to the total amount of the composition (X) is preferably 1% by mass or more and 20% by mass or less. If the percentage of the moisture absorbent (D) is 1% by mass or more, the cured product can have particularly high moisture absorption. If the percentage of the moisture absorbent (D) is 20% by mass or less, the viscosity of the composition (X) can be particularly reduced, and the composition (X) can have a sufficiently low viscosity to be applicable by the inkjet method. The percentage of the moisture absorbent (D) is more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The percentage of the moisture absorbent (D) is more preferably 15% by mass or less, and particularly preferably 13% by mass or less.

The composition (X) may further contain an inorganic filler other than the moisture absorbent (D). For example, the composition (X) may contain nano-sized high refractive index particles. Examples of high refractive index particles include zirconia particles. When the composition (X) contains high refractive index particles, the refractive index of the cured product can be increased while maintaining good transparency of the cured product. Therefore, when the cured product is applied to an optical component, the extraction efficiency of light that passes through the optical component and is emitted to the outside can be improved. The average particle size of the high refractive index particles is preferably within the range of 5 to 30 nm, and more preferably within the range of 10 to 20 nm.

The percentage of high refractive index particles in composition (X) is appropriately designed so that the cured product has the desired refractive index. In particular, it is preferable that the high refractive index particles are contained in composition (X) so that the refractive index of the cured product is in the range of 1.45 or more and less than 1.55. In this case, the light extraction efficiency of the light emitting device 1 is particularly improved.

When composition (X) contains moisture absorbent (D), composition (X) preferably further contains dispersant (E). In this case, dispersant (E) can improve the dispersibility of moisture absorbent (D) in composition (X). Therefore, composition (X) is less likely to experience an increase in viscosity and a decrease in storage stability due to moisture absorbent (D).

The dispersant (E) is a surfactant that can be adsorbed to particles. The dispersant (E) has an adsorption group (generally also called an anchor) that can be adsorbed to particles, and a molecular skeleton (generally also called a tail) that attaches to the particles by adsorbing the adsorption group to the particles. The dispersant (E) contains at least one component selected from the group consisting of, for example, an acrylic dispersant whose tail is an acrylic molecular chain, a urethane dispersant whose tail is a urethane molecular chain, and a polyester dispersant whose tail is a polyester molecular chain. The adsorption group includes, for example, at least one of a basic polar functional group and an acidic polar functional group. The basic polar functional group includes, for example, at least one group selected from the group consisting of an amino group, an imino group, an amide group, an imide group, and a nitrogen-containing heterocyclic group. The acidic polar functional group includes, for example, at least one group selected from the group consisting of a carboxyl group and a phosphate group. The dispersant (E) can contain at least one compound selected from the group consisting of, for example, the Solsperse series manufactured by Nippon Louvre Resol Co., Ltd., the DISPERBYK series manufactured by BYK Japan Co., Ltd., and the AJISPER series manufactured by Ajinomoto Fine-Techno Co., Ltd.

When the composition (X) contains a moisture absorbent (D), the amount of dispersant (E) per 100 parts by mass of the moisture absorbent (D) is preferably 5 parts by mass or more and 60 parts by mass or less. When the amount of dispersant (E) is 5 parts by mass or more, the function of the dispersant (E) can be effectively expressed, and when the amount is 60 parts by mass or less, free molecules of the dispersant (E) in the cured product can be prevented from inhibiting the adhesion between the cured product and the inorganic material member. In addition, the amount of dispersant (E) is more preferably 15 parts by mass or more, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

The structure of the light-emitting device 1 will be described. The light-emitting device 1 includes a light source and an optical component that transmits the light emitted by the light source. For example, the light-emitting device 1 includes a light-emitting element 4, and a sealant 5 and a passivation layer 6 that cover the light-emitting element 4. In this case, the light-emitting element 4 is the light source, the sealant 5 is the optical component, and the passivation layer 6 is an inorganic layer such as a silicon nitride film. The sealant 5 and the passivation layer 6 overlap each other.

The light-emitting element 4 includes, for example, a light-emitting diode. The light-emitting diode includes, for example, at least one of an organic EL element (organic light-emitting diode) and a micro light-emitting diode. When the light-emitting element 4 includes an organic light-emitting diode, the light-emitting device 1 including the light-emitting element 4 is, for example, an organic EL display. When the light-emitting element 4 includes a micro light-emitting diode, the light-emitting device 1 including the light-emitting element 4 is, for example, a micro LED display. Note that EL is an abbreviation for electroluminescence.

An example of the structure of the light-emitting device 1 will be described with reference to FIG. 1. This light-emitting device 1 is a top-emission type. The light-emitting device 1 includes a support substrate 2, a transparent substrate 3 that faces the support substrate 2 with a gap therebetween, a light-emitting element 4 on the surface of the support substrate 2 that faces the transparent substrate 3, and a passivation layer 6 and a sealing material 5 that cover the light-emitting element 4.

The support substrate 2 is made of, for example, but not limited to, a resin material. The transparent substrate 3 is made of a material having light transmissivity. The transparent substrate 3 is, for example, a glass substrate or a transparent resin substrate. The light-emitting element 4 includes, for example, a pair of electrodes 41, 43 and an organic light-emitting layer 42 between the electrodes 41, 43. The organic light-emitting layer 42 includes, for example, a hole injection layer 421, a hole transport layer 422, an organic light-emitting layer 423, and an electron transport layer 424, and these layers are stacked in the above order.

The light-emitting device 1 includes a plurality of light-emitting elements 4, which form an array 9 (hereinafter referred to as element array 9) on a support substrate 2. The element array 9 also includes a partition 7. The partition 7 is on the support substrate 2 and separates two adjacent light-emitting elements 4. The partition 7 is fabricated, for example, by forming a photosensitive resin material using a photolithography method. The element array 9 also includes connection wiring 8 that electrically connects the electrodes 43 and the electron transport layers 424 of adjacent light-emitting elements 4. The connection wiring 8 is provided on the partition 7.

The passivation layer 6 is preferably a silicon nitride film or a silicon oxide film, and is particularly preferably a silicon nitride film. In the example shown in FIG. 1, the passivation layer 6 includes a first passivation layer 61 and a second passivation layer 62. The first passivation layer 61 covers the element array 9 in a state where it is in direct contact with the element array 9, thereby covering the light-emitting element 4. The second passivation layer 62 is disposed on the opposite side of the element array 9 with respect to the first passivation layer 61, and a gap is provided between the second passivation layer 62 and the first passivation layer 61. The sealant 5 is filled between the first passivation layer 61 and the second passivation layer 62. That is, the first passivation layer 61 is interposed between the light-emitting element 4 and the sealant 5 covering the light-emitting element 4.

Furthermore, a second sealing material 52 is filled between the second passivation layer 62 and the transparent substrate 3. The second sealing material 52 is made of, for example, a transparent resin material. The material of the second sealing material 52 is not particularly limited. The material of the second sealing material 52 may be the same as or different from the sealing material 5.

A method for producing the encapsulant 5 using composition (X) and a method for producing the light emitting device 1 will be described.

In this embodiment, it is preferable to produce the sealant 5 by molding the composition (X) by the inkjet method and then irradiating the composition (X) with ultraviolet light to harden it. In this embodiment, the composition (X) can be applied and molded by the inkjet method. As described above, in this embodiment, the percentage of oxygen in the composition (X) is 75 mass % or less, so that defects are unlikely to occur when the composition (X) is molded by the inkjet method.

More specifically, for example, first, the support substrate 2 is prepared. On one surface of the support substrate 2, the partition walls 7 are fabricated, for example, by photolithography using a photosensitive resin material. Next, a plurality of light-emitting elements 4 are provided on one surface of the support substrate 2. The light-emitting elements 4 can be fabricated by an appropriate method such as a vapor deposition method or a coating method. In particular, it is preferable to fabricate the light-emitting elements 4 by a coating method such as an inkjet method. In this way, an element array 9 is fabricated on the support substrate 2. The tops of the partition walls 7 protrude beyond the surfaces of the light-emitting elements 4, and the dimension from the surface of the light-emitting elements 4 to the tops of the partition walls 7 is, for example, 0.1 μm or more and 1.5 μm or less. The distance between adjacent partition walls 7 is, for example, 30 μm or more and 150 μm or less.

Next, a first passivation layer 61 is provided on the element array 9. The first passivation layer 61 can be produced by a deposition method such as a plasma CVD method.

The first passivation layer 61 is formed to cover the multiple light-emitting elements 4 and the partition walls 7. As described above, the tops of the partition walls 7 protrude beyond the surfaces of the light-emitting elements 4, so that the surface of the first passivation layer 61 has irregularities that follow the shape of the partition walls 7.

Next, the composition (X) is applied onto the first passivation layer 61 by, for example, an inkjet method to form a coating film. If the inkjet method is used for both the formation of the light-emitting element 4 and the application of the composition (X), the manufacturing efficiency of the light-emitting device 1 can be particularly improved.

As described above, in this embodiment, composition (X) contains 10 mass % or more of water-soluble compound (C) and has a viscosity of 30 mPa·s or less. Therefore, even if a coating film of composition (X) is formed on the first passivation layer 61, which is a silicon nitride film or the like, and the surface of the first passivation layer 61 has irregularities, the surface of the coating film is likely to be flat and smooth.

The coating film of composition (X) is cured by irradiating it with ultraviolet light. This produces a sealant 5, which is a cured film of composition (X). The surface of this sealant 5 tends to be flat and smooth.

Next, a second passivation layer 62 is provided on the sealing material 5. The second passivation layer 62 can be produced by a deposition method such as plasma CVD.

Next, an ultraviolet-curable resin material is applied to one surface of the support substrate 2 so as to cover the second passivation layer 62, and then the transparent substrate 3 is placed on top of this resin material. The transparent substrate 3 is, for example, a glass substrate or a transparent resin substrate.

Next, ultraviolet light is applied from the outside toward the transparent substrate 3. The ultraviolet light passes through the transparent substrate 3 and reaches the ultraviolet-curable resin material. This causes the ultraviolet-curable resin material to harden, producing the second sealing material 52.

The thickness of the sealing material 5 is, for example, 50 μm or less. In this case, by thinning the sealing material 5, the light emitting device 1 can be thinned, and a flexible light emitting device 1 can be obtained. In addition, in this embodiment, the surface of the sealing material 5 is likely to be flat and smooth, so that even if the thickness of the sealing material 5 is 15 μm or less, a sealing material 5 having a flat and smooth surface is likely to be obtained. It is more preferable that the thickness of the sealing material is 10 μm or less, and even more preferable that the thickness is 5 μm or less. In addition, in order to effectively suppress moisture to the light emitting element 4 by the sealing material 5, it is preferable that the thickness of the sealing material 5 is 1 μm or more, and more preferably 2 μm or more.

The thickness of the passivation layer 6 overlapping the sealing material 5 is, for example, 0.1 μm or more and 2 μm or less. When the passivation layer 6 includes the first passivation layer 61 and the second passivation layer 62 as described above, it is preferable that the thickness of each of the first passivation layer 61 and the second passivation layer 62 is 0.1 μm or more and 2 μm or less.

The use of the composition (X) according to this embodiment is not limited to the preparation of the encapsulant 5 for the light-emitting element 4. The composition (X) can be used to prepare various optical components that transmit light emitted by a light source. For example, the optical component may be a color resist. That is, for example, a phosphor may be contained in the composition (X), and a color resist in a color filter may be prepared on an inorganic material from this composition (X). This color filter can be provided in a display device such as an organic EL display or a micro LED display, which is a light-emitting device.

1. Preparation of Compositions Compositions of the examples and comparative examples were prepared by mixing the components shown in the table below.

The details of the components shown in the table are as follows: The viscosity of each component was measured using a rheometer (manufactured by Anton Paar Japan, model DHR-2) at a temperature of 25° C. and a shear rate of 1000 s ^-1 .
- Epoxy compound 1: water-insoluble, compound name tetrahydroindene diepoxide, manufactured by ENEOS Corporation, product name THI-DE, viscosity 20 mPa·s.
- Epoxy compound 2: Water-soluble, 1,4-butanediol diglycidyl ether, manufactured by Yokkaichi Synthetic Co., Ltd., product name Epogosei BD (D), viscosity 8.4 mPa·s.
- Epoxy compound 3: Water-soluble, ethylene glycol diglycidyl ether, manufactured by Kyoeisha Chemical Co., Ltd., product name Epolite 400E, viscosity 85 mPa·s.
-Oxetane compound 1: water-insoluble, 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (compound represented by formula (3)), manufactured by Toagosei Co., Ltd., product number OXT-221, viscosity 10 mPa·s.
-Oxetane compound 2: Water-soluble, 3-ethyl-3-hydroxymethyloxetane (oxetane alcohol), manufactured by Toagosei Co., Ltd., product number OXT-101, viscosity 19.5 mPa·s.
-Oxetane compound 3: Water-soluble, (3-ethyl-3-(4-hydroxybutyloxymethyl)oxetane, manufactured by Ube Industries, Ltd., product number ETERNACOLL (registered trademark) HBOX, viscosity 29 mPa·s.
Photopolymerization initiator: triarylsulfonium salt-based photoacid generator, San-Apro Ltd., product number CPI-210S.
Sensitizer: Manufactured by Kawasaki Chemical Industries, Ltd., product name: Anthracure (registered trademark) UVS1331.
Leveling agent: phenyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., product name KBM-103.

2. Evaluation Tests The following evaluation tests were carried out on the Examples and Comparative Examples. The results are shown in the Table.

(1) Flatness/Smoothness (Urokomura)
A photosensitive polyimide resin (manufactured by Toray, product name Photoneece DL-1000) was applied onto a glass substrate and then heated at 120° C. for 3 minutes using a hot plate to prepare a prebaked film. The thickness was measured using a spectrophotometer (U-4100) manufactured by High Technology and found to be 2 μm. The prebaked film was exposed to light through a photomask and then developed with a developer (a 2.38% by weight solution of tetramethylammonium hydroxide). ) for 60 seconds, and then heated in a clean oven at 250° C. for 60 minutes. As a result, partition walls (black matrix) with a height of 0.5 μm arranged in a lattice pattern were formed on the glass substrate. The opening surrounded by the partition has a planar dimension of 70 μm×250 μm.

A silicon nitride film 500 nm thick was formed over the entire surface of the glass substrate on which the partition walls were formed, covering the partition walls.

The composition was placed in the cartridge of an inkjet printer (FUJIFILM Corporation, Material Printer MP2831), and after confirming that the composition in the cartridge could be ejected from the nozzle of the inkjet printer, droplets of the composition were ejected from the nozzle at 600 dpi to produce a coating film with a maximum thickness of 5 μm.

Five minutes after the coating film was prepared, the coating film was photocured by irradiating it with light in dry air using an LED-UV irradiator manufactured by CCS Inc. under conditions of a peak wavelength of 395 nm, an output of 100 mW/ ^cm2 , and an accumulated light quantity of 1,500 mJ/ ^cm2 , to prepare an encapsulant.

The coating was observed 5 minutes after it was made and immediately before it was irradiated with light. If the surface of the coating was flat, it was rated as "A."

If the coating was not rated as "A", the coating was left for 20 minutes without being exposed to light after preparation as described above, and then the coating was observed. If the surface of the coating was flat, it was rated as "B", and if the surface of the coating was wavy, it was rated as "C".

(2) Viscosity The viscosity of the composition was measured using a rheometer (Model DHR-2, manufactured by Anton Paar Japan) at a temperature of 25° C. and a shear rate of 1000 s ⁻¹ .

(3) Transmittance A coating film having a thickness of 10 μm was prepared by applying the composition, and this coating film was irradiated with ultraviolet light at an irradiation intensity of 3 W/ ^cm2 for 5.3 seconds under atmospheric conditions using an LED-UV irradiator (model number E075IIHD, peak wavelength 395 nm) manufactured by Ushio Inc., and then heated at 100° C. for 5 minutes to prepare a film. The total light transmittance of this film was measured according to JIS K7361-1.

(4) Inkjet properties The composition was placed in the cartridge of an inkjet printer (Model DMP2831, manufactured by Fujifilm), and droplets of the composition were ejected from the nozzle of the inkjet printer under conditions of a temperature of 30° C. and a frequency of 1 kHz. The droplets were observed with a high-speed camera, and were rated as "A" when neither mist nor satellites were observed, and "B" when at least one of mist and satellites was observed.

(5) Glass Transition Temperature A coating film was prepared by coating the composition, and the coating film was photocured by irradiating the coating film with ultraviolet light under an atmospheric condition at an irradiation intensity of 5 W/ ^cm2 and an accumulated light quantity of 5000 mJ/ ^cm2 using a Unijet E075IIHD (peak wavelength 395 nm) manufactured by Ushio Inc., to prepare a film having a thickness of 200 μm. The glass transition temperature of a sample cut out from the film was measured using a viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Corporation, model number DMA7100).

(6) Outgassing Evaluation The outgassing when the cured product of the composition was heated was sampled by the headspace method and measured by gas chromatography. In detail, 100 mg of the composition was first placed in a headspace vial with a volume of 22 mL. Next, the composition was cured by irradiating the composition with ultraviolet light under atmospheric conditions at an irradiation intensity of 5 W/cm ² and an accumulated light quantity of 1500 mJ/cm ² using a Unijet E075IIHD (peak wavelength 395 nm) manufactured by Ushio Electric Co., Ltd., and then the vial was sealed. Next, the composition was heated at 100° C. for 30 minutes, and then the gas phase portion in the vial was introduced into a gas chromatograph for analysis. As a result, the concentration of the outgassing generated from the composition was specified based on the peak area of the obtained gas chromatogram. The concentration of the outgassing is the volume fraction of the outgassing in the gas phase of the vial relative to the volume of the vial (22 mL).

The outgassing concentration was determined using toluene as the reference substance. Specifically, two reference samples with toluene concentrations of 1000 ppm and 100 ppm were prepared by volatilizing toluene in a vial. Each reference sample was introduced into a gas chromatograph for analysis. From the peak areas of the two chromatograms obtained in this way, the relationship between peak area and concentration was determined, and the above-mentioned outgassing concentration was determined based on these results.

As a result, outgassing concentrations (volume fraction) of 50 ppm or less were rated as "A," those between 50 ppm and 100 ppm or less were rated as "B," those between 100 ppm and 200 ppm or less were rated as "C," and those over 200 ppm were rated as "D."

Claims (10)

The ultraviolet-curable resin composition contains a photopolymerizable compound (A), a photopolymerization initiator (B), and a sensitizer,
the photopolymerizable compound (A) contains a water-soluble compound (C), and the percentage of the water-soluble compound (C) relative to the ultraviolet-curable resin composition is 10 mass% or more;
The viscosity at 25°C is 30 mPa·s or less,
The photopolymerizable compound (A) contains a cationic polymerizable compound (A2),
The cationically polymerizable compound (A2) contains a cyclic ether compound,
The cyclic ether compound contains an epoxy compound and an oxetane compound,
The epoxy compound contains a water-soluble epoxy compound (C21),
the percentage of the water-soluble epoxy compound (C21) relative to the oxetane compound is 10/60 mass% or more and 50 mass% or less;
The sensitizer contains either one or both of 9,10-dibutoxyanthracene and 9,10-diethoxyanthracene.
UV curable resin composition. The percentage of the water-soluble compound (C) relative to the photopolymerizable compound (A) is 50 mass% or less.
The ultraviolet-curable resin composition according to claim 1 . To produce an optical component that transmits light emitted by a light source,
The ultraviolet-curable resin composition according to claim 1 or 2. Formed by the inkjet method,
The ultraviolet-curable resin composition according to claim 1 . A cured product of the ultraviolet-curable resin composition according to any one of claims 1 to 4.
Optical components. The method includes molding the ultraviolet-curable resin composition according to any one of claims 1 to 4 by an inkjet method, and then irradiating the ultraviolet-curable resin composition with ultraviolet light to cure the composition.
A method for manufacturing optical components. Fabricating the optical component on a silicon nitride film;
The method for producing the optical component according to claim 6 . A light source and an optical component that transmits light emitted by the light source, the optical component including a cured product of the ultraviolet-curable resin composition according to any one of claims 1 to 4.
Light emitting device. Further comprising a silicon nitride membrane;
the optical component overlies the silicon nitride membrane;
The light emitting device according to claim 8. A method for manufacturing a light emitting device including a light source and an optical component that transmits light emitted by the light source, comprising the steps of:
The optical component is manufactured by the method according to claim 6 or 7.
A method for manufacturing a light emitting device.

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