Active energy ray-curable composition and optical article or optical sheet

Abstract

According to the present invention, it is possible to provide an active energy ray-curable composition and an optical article or an optical sheet, which have good light resistance and a high refractive index. An active energy ray-curable composition according to the present invention contains inorganic fine particles (A), a dispersant (B), and a (meth)acrylate (C) having an aliphatic cyclic structure. A cured product of the active energy ray-curable composition has a film refractive index of 1.60-1.75.

Description

Active energy ray-curable composition, optical article or optical sheet

[0001] The present invention relates to an active energy ray-curable composition, an optical article, or an optical sheet. This application claims priority to Japanese Patent Application No. 2023-195945, filed on November 17, 2023, the contents of which are incorporated herein by reference.

[0002] In recent years, optical sheets with functions such as improving brightness and widening the viewing angle have been used in displays such as liquid crystal display devices. Furthermore, optical sheets and optical articles are used in head-mounted displays (HMDs) and smart glasses, which are worn on the user's head, to realize systems such as virtual reality (VR), augmented reality (AR), and mixed reality (MR). Such optical sheets and optical articles typically have a substrate and an optical functional layer on the substrate that has a fine uneven structure. The uneven surface modulates light through geometrical optics and wave optics, such as refraction and diffraction, to achieve the desired function. Materials used in the optical functional layer are required to have a high refractive index. To address this, methods have been proposed in which a (meth)acrylate with a high refractive index is used or organic or inorganic fine particles with a high refractive index are added (for example, Patent Documents 1 to 3).

[0003] International Publication No. 2020 / 250721 Japanese Patent Application Laid-Open No. 2013-249439 Japanese Patent Application Laid-Open No. 2010-85539

[0004] However, these optical sheets have problems such as insufficient light resistance, thinning of the film due to light exposure, yellowing, etc. Therefore, there has been a demand for materials that have good light resistance and a high refractive index.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an active energy ray-curable composition, an optical article, or an optical sheet that has good light resistance and a high refractive index.

[0006] The present invention has been filed based on the discovery that a high refractive index and good light resistance can be achieved by setting the content of monofunctional (meth)acrylate in a specific range in a (meth)acrylate compound and incorporating a certain amount of inorganic fine particles. The present disclosure includes the following embodiments. [1] An active energy ray-curable composition containing inorganic fine particles (A), a dispersant (B), and a (meth)acrylate (C) having an alicyclic structure, wherein the film refractive index of a cured product of the active energy ray-curable composition is 1.60 to 1.75. [2] The active energy ray-curable composition according to [1], wherein the inorganic fine particles (A) are at least one selected from the group consisting of zirconia, titania, niobium oxide, and barium titanate. [3] The active energy ray-curable composition according to [1] or [2], wherein the (meth)acrylate (C) having an alicyclic structure is a compound having at least one selected from the group consisting of structures represented by the following general formulas (1) and (2): (General formula (1), (2), (3), middle, R １ , R ２ , R ５ , R ７ are each independently a hydrogen atom or a methyl group. ３ , R ４ are each independently a direct bond methylene group or an ethylene oxide chain having 4 or less repeating units. ６ , R ８ is a directly bonded oxygen atom or an ethylene oxide chain having 4 or less repeating units.) [4] The active energy ray-curable composition according to any one of [1] to [3], further comprising a photopolymerization initiator (D). [5] An optical article or optical sheet comprising a cured product pattern of the active energy ray-curable composition according to [4]. [6] The optical article or optical sheet according to [5], wherein the line width of the cured product pattern is 50 μm or less.

[0007] According to the present invention, it is possible to provide an active energy ray-curable composition, an optical article, or an optical sheet that has good light resistance and a high refractive index.

[0008] The present invention will be described in more detail below, but the present invention is not limited to the following embodiments.

[0009] The symbol "to" means greater than or equal to the value before it and less than or equal to the value after it. "(Meth)acrylic" is a general term for acrylic and methacrylic, and "(meth)acrylate" is a general term for acrylate compounds and methacrylate compounds.

[0010] (Active Energy Ray-Curable Composition) The active energy ray-curable composition according to this embodiment contains inorganic fine particles (A), a dispersant (B), and a (meth)acrylate having an aliphatic cyclic structure (C), and the film refractive index of a cured product of the active energy ray-curable composition is 1.60 to 1.75.

[0011] [Inorganic fine particles (A)] The inorganic fine particles (A) (sometimes referred to as "component (A)") according to this embodiment are preferably one or more selected from the group consisting of zirconia, niobium oxide, niobium oxide, silica, barium sulfate, zinc oxide, barium titanate, cerium oxide, alumina, and titania (titanium oxide). Among these, one or more selected from the group consisting of zirconia, niobium oxide, barium titanate, and titania (titanium oxide) are more preferred. The crystalline structure of the inorganic fine particles (A) according to this embodiment is not particularly limited, but for example, when the inorganic fine particles (A) are zirconia, a monoclinic system is preferred because it provides excellent dispersion stability and a cured product with high light transmittance and refractive index.

[0012] The inorganic fine particles (A) according to the present embodiment may be any known particles, and the particle shape is not particularly limited, but may be, for example, spherical, hollow, porous, rod-like, plate-like, fibrous, or amorphous. Among these, spherical particles are preferred because they have excellent dispersion stability and can give a cured product with high light transmittance and refractive index.

[0013] <Zirconia Nanoparticles> The inorganic fine particles (A) according to this embodiment are preferably zirconia nanoparticles. Conventional zirconia nanoparticles can be used. The particle shape is not particularly limited, but examples include spherical, hollow, porous, rod-like, and fibrous shapes. Of these, spherical shapes are preferred. The average primary particle diameter of the zirconia nanoparticles according to this embodiment is preferably 1 to 50 nm, more preferably 1 to 30 nm. Furthermore, the crystal structure is not particularly limited, but a monoclinic system is preferred. The average primary particle diameter in this embodiment can be measured by directly measuring the size of primary particles from electron micrographs using a transmission electron microscope (TEM). For example, the measurement method involves measuring the minor axis diameter and major axis diameter of each primary particle of the inorganic fine particles and averaging the measured values ​​to determine the average primary particle diameter of the primary particles. Specific examples of zirconia nanoparticles according to this embodiment include UEP-100 (average primary particle diameter: 11 nm) manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd. and PCS (average primary particle diameter: 20 nm) manufactured by Nippon Denko Corporation.

[0014] The content of the inorganic fine particles (A) in the active energy ray-curable composition of this embodiment is preferably 20 to 90 mass %, more preferably 30 to 80 mass %, and more preferably 40 to 70 mass % of the active ingredient. By setting it within these ranges, both good light resistance and a high refractive index can be achieved.

[0015] [Dispersant (B)] The dispersant (B) (sometimes referred to as "component (B)") contained in the active energy ray-curable composition of the present embodiment essentially contains a phosphate ester compound (b1) having at least one (meth)acryloyl group and at least one polyester chain, and a hydroxyl group-containing compound (b2) having a molecular weight of not more than 250. It is preferable that the dispersant (B) contains the phosphate ester compound (b1) containing the above-mentioned phosphate ester.

[0016] <Phosphate Ester Compound (b1)> The phosphate ester compound (b1) according to this embodiment is not particularly limited, and examples thereof include compounds having a polyester chain, such as DISPERBYK-110 and DISPERBYK-111 (manufactured by BYK Japan KK).

[0017] The phosphate ester compound (b1) is not particularly limited as long as it has at least one (meth)acryloyl group and at least one polyester chain. Examples of compounds having a (meth)acryloyl group include compounds represented by the following structural formula (4), which are preferred because they give an inorganic fine particle dispersion having excellent dispersion stability, and a curable composition containing the compound has light resistance and can form a cured coating film having high refractive index performance.

[0018] (In the formula R ９ is a hydrogen atom or a methyl group, and R １０ is an alkylene chain having 2 to 4 carbon atoms, x is an integer of 4 to 10, y is an integer of 1 or more, and n is an integer of 1 to 3.

[0019] In the phosphate ester compound represented by the structural formula (4), x is preferably 4 or 5, and y is preferably an integer from 1 to 7, because the resulting active energy ray-curable composition can form a cured coating film having high refractive index performance and light resistance. Furthermore, the dispersant (B) represented by the structural formula (4) may be a mixture in which n is 1, 2, and / or 3.

[0020] <Hydroxyl Group-Containing Compound (b2)> As the hydroxyl group-containing compound (b2), one having a molecular weight of 250 or less is used.

[0021] Examples of the hydroxyl group-containing compound (b2) include methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, sec-butanol, tert-butanol, heptanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, allyl alcohol, cyclohexanol, terpineol, terpineol, dihydroterpineol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monobutyl ether.

[0022] Examples of the hydroxyl group-containing compound (b2) that can be used include hydroxyl group-containing (meth)acrylate compounds such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trimethylolpropane (meth)acrylate, and pentaerythritol acrylate; (poly)oxyalkylene-modified compounds in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain has been introduced into the molecular structure of the hydroxyl group-containing (meth)acrylate compound; and lactone-modified compounds in which a (poly)lactone structure has been introduced into the molecular structure of the hydroxyl group-containing (meth)acrylate compound.

[0023] Among these, lactone-modified compounds in which a (poly)lactone structure is introduced into the molecular structure of a hydroxyl group-containing (meth)acrylate compound are preferred, because the resulting inorganic fine particle dispersion has excellent dispersion stability, and the curable composition containing the compound has low viscosity and can form a cured coating film having high refractive index performance and excellent bleed-out resistance. Furthermore, these hydroxyl group-containing compounds (b2) can be used alone or in combination of two or more.

[0024] The amount of the hydroxyl group-containing compound (b2) used is preferably in the range of 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the phosphate ester compound (b1), because the resulting inorganic fine particle dispersion has excellent dispersion stability, and the curable composition containing the compound has low viscosity and can form a cured coating film having high refractive index performance and excellent bleed-out resistance.

[0025] The dispersant (B) may be used in combination with other dispersants, if necessary.

[0026] Examples of the other dispersants include anionic dispersants having an acid group, such as carboxylic acid, sulfuric acid, sulfonic acid, and salts of these acid compounds. These other dispersants can be used alone or in combination of two or more.

[0027] The content of the dispersant (B) in the active energy ray-curable composition is more preferably in the range of 5 to 40 parts by mass, and even more preferably in the range of 10 to 25 parts by mass, per 100 parts by mass of zirconia, because a cured coating film having high refractive index performance and excellent light resistance can be formed.

[0028] [(Meth)acrylate (C) Having an Aliphatic Cyclic Structure] The (meth)acrylate (C) having an aliphatic cyclic structure according to this embodiment (sometimes referred to as "the (meth)acrylate (C) according to this embodiment) or "component (C)") includes compounds having at least one structure selected from the group consisting of structures represented by the following general formulas (1) and (2).

[0029]

[0030] (General formula (1), (2), (3), middle, R １ , R ２ , R ５ , R ７ are each independently a hydrogen atom or a methyl group. ３ , R ４ are each independently a direct bond methylene group or an ethylene oxide chain having 4 or less repeating units. ６ , R ８ is a directly bonded oxygen atom or an ethylene oxide chain of 4 or less repeating units.

[0031] <(Meth)acrylate (C1)> The (meth)acrylate (C) having the structure represented by the above general formula (1) (hereinafter, sometimes referred to as (meth)acrylate (C1)) is a (meth)acrylate having the structure represented by the above general formula (1), wherein R １ , R ２ are preferably each independently a hydrogen atom or a methyl group. ３ , R ４ are each preferably independently a methylene group or an ethylene oxide group having 4 or less repeating units, and more preferably a methylene group or an ethylene oxide group having 2 or less repeating units.

[0032] Examples of the (meth)acrylate (C1) according to this embodiment include tricyclodecane dimethanol diacrylate and tricyclodecane dimethanol dimethacrylate.

[0033] <(Meth)acrylate (C2)> The (meth)acrylate (C) having the structure represented by the above general formula (2) (hereinafter, sometimes referred to as (meth)acrylate (C2)) is a (meth)acrylate (C) having the structure represented by the above general formula (2), ５ is preferably a hydrogen atom or a methyl group. ６ is preferably a directly bonded oxygen atom or an ethylene oxide chain having 4 or fewer repeating units, and more preferably a directly bonded oxygen atom or an ethylene oxide chain having 2 or fewer repeating units.

[0034] Examples of the (meth)acrylate (C2) according to this embodiment include dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyl methacrylate, and dicyclopentenyloxyethyl methacrylate.

[0035] <(Meth)acrylate (C3)> The (meth)acrylate (C) having the structure represented by the above general formula (3) (hereinafter, sometimes referred to as (meth)acrylate (C3)) is a (meth)acrylate (C) having the structure represented by the above general formula (3), ７ is preferably a hydrogen atom or a methyl group. ８ is preferably a directly bonded oxygen atom or an ethylene oxide chain having 4 or fewer repeating units, and more preferably a directly bonded oxygen atom or an ethylene oxide chain having 2 or fewer repeating units.

[0036] Examples of the (meth)acrylate (C3) according to this embodiment include dicyclopentanyl acrylate, dicyclopentanyloxyethyl acrylate, dicyclopentanyl methacrylate, and dicyclopentanyloxyethyl methacrylate.

[0037] The content of the (meth)acrylate (C) according to this embodiment in the active energy ray-curable composition according to this embodiment is preferably 5 to 80 mass %, more preferably 15 to 70 mass %, and more preferably 20 to 60 mass % of the active ingredient. This is because when the content of the (meth)acrylate (C) according to this embodiment is in the above range, the composition has good light resistance and a high refractive index.

[0038] The (meth)acrylate (C) according to this embodiment does not include a dispersant (B) having a (meth)acryloyl group, or a silane coupling agent (E) having a (meth)acryloyl group or a (meth)acryloyloxy group.

[0039] [Photopolymerization initiator (D)] The active energy ray-curable composition according to this embodiment may further contain a photopolymerization initiator (D). The photopolymerization initiator (D) according to this embodiment (sometimes referred to as "component (D)") is not particularly limited as long as it has the function of initiating polymerization of the (meth)acryloyl group of the (meth)acrylate (C) according to this embodiment or the like upon photoexcitation, and examples thereof include an intramolecular bond cleavage type photopolymerization initiator (D) and an intramolecular hydrogen abstraction type photopolymerization initiator (D). For example, a monocarbonyl compound, a dicarbonyl compound, an acetophenone compound, a benzoin ether compound, an acylphosphine oxide compound, an aminocarbonyl compound, etc. can be used.

[0040] Examples of the intramolecular bond cleavage type photopolymerization initiator (D) include acetophenone-based initiators such as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone; benzoins such as benzoin methyl ether and benzoin isopropyl ether; acylphosphine oxide-based initiators such as 2,4,6-trimethylbenzoin diphenylphosphine oxide; and benzyl and methylphenyl glyoxyesters.

[0041] The intramolecular hydrogen abstraction type photopolymerization initiator (D) may be, for example, a benzophenone, o-benzoylmethylbenzoate-4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, or 3,3'-dimethyl-4-methoxybenzophenone. thioxanthone-based compounds such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone; aminobenzophenone-based compounds such as Michler's ketone and 4,4'-diethylaminobenzophenone; 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone, Ueda Susume, Nishida Monthly Report, etc. The photopolymerization initiator (D) is preferably Runtecure-1104 or Omnirad-819, and these may be used in combination.

[0042] Commercially available products of the photopolymerization initiator (D) include, for example, "Omnirad-1173", "Omnirad-184", "Omnirad-127", "Omnirad-2959", "Omnirad-369", "Omnirad-379", "Omnirad-907", "Omnirad-4265", "Omnirad-1000", "Omnirad-651", "Omnirad-TPO", "Omnirad-819", "Omnirad-2022", "Omnirad-2100", "Omnirad-754", "Omnirad-784", "Omnirad-500", "Omnirad-81", and "Omnirad 4-MBZ”, “Omnirad 1314”, “Esacure KT55”, “Esacure TZT”, “Eascure ONE”, “LFC4563”, Omnipol BP, Omnipol ASA, Omnipol 910, Omnipol TP (manufactured by IGM), "Kayacure-DETX", "Kayacure-MBP", "Kayacure-DMBI", "Kayacure-EPA", "Kayacure-OA" (manufactured by Nippon Kayaku Co., Ltd.), "Baicure-10", "Baicure-55" (manufactured by Stauffer Chemical Co., Ltd.), "Trigonal P1" (manufactured by Akzo Chemicals), "Sandray 1000" (manufactured by Sandoz), "Deep" (manufactured by Upjohn Chemical), "Quantacure-PDO", "Quantacure-ITX", "Quantacure-EPD" (manufactured by Ward-Blenkinsop), "Runtecure-1104" (manufactured by Runtec), "Darocur MBF" (manufactured by BASF), and the like. These photopolymerization initiators can be used alone or in combination of two or more.

[0043] The photopolymerization initiator (D) is not limited to the above compounds and may be any compound capable of initiating polymerization by ultraviolet light. These photopolymerization initiators (D) may be used singly or in combination of two or more. The amount of the photopolymerization initiator (D) used is not particularly limited, but is preferably used in the range of 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the solids (non-volatile content) of the active energy ray-curable composition of this embodiment. A known organic amine or the like may also be added as a sensitizer. Furthermore, in addition to the radical polymerization initiator, a cationic polymerization initiator may also be used in combination. The solids (non-volatile content) mass of the composition refers to the total mass of all components of the composition excluding the solvent contained in the active energy ray-curable composition of this embodiment.

[0044] [Silane Coupling Agent (E)] The active energy ray-curable composition of the present embodiment may further contain a silane coupling agent (E) (sometimes referred to as "component (E)"). Examples of the silane coupling agent (E) according to the present embodiment include (meth)acryloyloxy-based silane coupling agents such as 3-(meth)acryloyloxypropyltrimethylsilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, and 3-(meth)acryloyloxypropyltriethoxysilane; vinyl-based silane coupling agents such as allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane, trichlorovinylsilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(2-methoxyethoxy)silane; Epoxy-based silane coupling agents such as diethoxy(glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; styrene-based silane coupling agents such as p-styryltrimethoxysilane; amino-based silane coupling agents such as N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane; ureido-based silane coupling agents such as 3-ureidopropyltriethoxysilane; Chloropropyl-based silane coupling agents such as 3-chloropropyltrimethoxysilane; mercapto-based silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane;Examples of suitable silane coupling agents include sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide; isocyanate-based silane coupling agents such as 3-isocyanatepropyltriethoxysilane; and aluminum-based silane coupling agents such as acetoalkoxyaluminum diisopropylate. These silane coupling agents (E) can be used alone or in combination of two or more. Among these, 3-(meth)acryloyloxypropyltrimethoxysilane is preferred due to its good compatibility with the acrylate compound (B). The amount of silane coupling agent (E) used in this embodiment is preferably in the range of 10 to 30 parts by mass per 100 parts by mass of the inorganic fine particles (A), as this allows the resulting active energy ray-curable composition to have excellent dispersion stability and to form a cured coating film that is light-resistant and has a high refractive index.

[0045] [Other (meth)acrylates (F)] The active energy ray-curable composition according to this embodiment may contain, for example, the following monofunctional (meth)acrylate or polyfunctional (meth)acrylate (F) (sometimes referred to as "component (F)") that does not belong to the (meth)acrylate (C) according to this embodiment.

[0046] <Monofunctional (meth)acrylate> The monofunctional (meth)acrylate is a monofunctional (meth)acrylate having one active energy ray-curable group, and may be a chain aliphatic, cyclic alicyclic, or aromatic (meth)acrylate containing a heteroatom such as a halogen atom, a sulfur atom, an oxygen atom, or a nitrogen atom. For example, the monofunctional (meth)acrylates described in Patent Document 1 can be used.

[0047] Examples of the monofunctional (meth)acrylate include aromatic mono(meth)acrylate compounds, aliphatic mono(meth)acrylate compounds, alicyclic mono(meth)acrylate compounds, heterocyclic mono(meth)acrylate compounds, and hydroxyl group-containing mono(meth)acrylate compounds. Examples of the monofunctional (meth)acrylate include polyoxyalkylene-modified mono(meth)acrylate compounds in which a polyoxyalkylene chain such as a polyoxyethylene chain, a polyoxypropylene chain, or a polyoxytetramethylene chain is introduced into the molecular structure of the various mono(meth)acrylate compounds; and lactone-modified mono(meth)acrylate compounds in which a (poly)lactone-derived structure is introduced into the molecular structure of the various mono(meth)acrylate compounds.

[0048] Examples of the aromatic mono(meth)acrylate compound include benzyl(meth)acrylate, phenyl(meth)acrylate, phenoxy(meth)acrylate, phenoxyethyl(meth)acrylate, phenoxyethoxyethyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, phenoxybenzyl(meth)acrylate, biphenylmethyl(meth)acrylate, benzylbenzyl(meth)acrylate, phenylphenoxyethyl(meth)acrylate, phenylphenol(EO)n(meth)acrylate, and phenol(EO)n(meth)acrylate.

[0049] Examples of the aliphatic mono(meth)acrylate compound include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, tert-butyl(meth)acrylate, n-pentyl(meth)acrylate, n-hexyl(meth)acrylate, n-octyl(meth)acrylate, isooctyl(meth)acrylate, and 2-ethylhexyl(meth)acrylate. Examples of the alicyclic mono(meth)acrylate compounds include cyclohexyl (meth)acrylate, adamantyl mono(meth)acrylate, cyclohexylmethyl (meth)acrylate, cyclohexylethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. Examples of the heterocyclic mono(meth)acrylate compounds include glycidyl (meth)acrylate and tetrahydrofurfuryl acrylate. Examples of the hydroxyl group-containing mono(meth)acrylate compounds include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. Examples of the lactone-modified mono(meth)acrylate compounds include caprolactone-modified tetrahydrofurfuryl (meth)acrylate.

[0050] The monofunctional (meth)acrylates may be used alone or in combination of two or more.

[0051] <Polyfunctional (meth)acrylate>

[0052] The polyfunctional (meth)acrylate is preferably a polyfunctional (meth)acrylate having three or more active energy ray-curable groups, and may be a chain aliphatic, cyclic alicyclic, or aromatic (meth)acrylate containing a heteroatom such as a halogen atom, a sulfur atom, an oxygen atom, or a nitrogen atom, and for example, the polyfunctional (meth)acrylate described in Patent Document 1 can be used.

[0053] Examples of the polyfunctional (meth)acrylate include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, tetrabutylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, glycerol di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, caprolactone-modified neopentyl glycol hydroxypivalate di(meth)acrylate, tetrabromobisphenol A di(meth)acrylate, hydropivalaldehyde-modified trimethylolpropane di(meth)acrylate, bisphenol fluorene di(meth)acrylate, bisphenol fluorene (EO) ｎ Di(meth)acrylate, bisphenol A (EO) ｎ Di(meth)acrylate, trimethylolpropane (EO) ｎ tri(meth)acrylate, 1,4-cyclohexanedimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerol tri(meth)acrylate, alkyl-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetra(meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate, and other polyfunctional (meth)acrylates.

[0054] These polyfunctional (meth)acrylates can be used alone or in combination of two or more. Among these, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, a reaction product of pentaerythritol and acrylic acid, a reaction product of dipentaerythritol and acrylic acid, and the like are preferred, since they can give (meth)acrylic resins excellent in drying properties, ink fluidity, and suitability for high-speed printing.

[0055] <Other additives>

[0056] The composition of the present invention may contain other additives as needed. Examples of the other additives include photosensitizers, ultraviolet absorbers, antioxidants, silicone-based additives, fluorine-based additives, rheology control agents, defoamers, antistatic agents, and antifogging agents. When these other additives are added, the amount added is preferably in the range of 0.01 to 40% by mass in the composition of the present invention.

[0057] Examples of the photosensitizer include amine compounds such as aliphatic amines and aromatic amines, urea compounds such as o-tolylthiourea, and sulfur compounds such as sodium diethyldithiophosphate and s-benzylisothiuronium-p-toluenesulfonate. These photosensitizers can be used alone or in combination of two or more. When these photosensitizers are added, the amount added is preferably in the range of 0.01 to 10% by mass in the composition. Adding a photosensitizer can improve curability.

[0058] [Solvent] The active energy ray-curable composition of this embodiment may contain a solvent. The solvent is not particularly limited, and various known organic solvents can be used. Specific examples include cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, acetone, acetylacetone, toluene, xylene, n-butanol, isobutanol, tert-butanol, n-propanol, isopropanol, ethanol, methanol, 3-methoxy-1-butanol, 3-methoxy-2-butanol, ethylene glycol monomethyl ether, ethylene glycol mono-n-butyl ether, 2-ethoxyethanol, 1-methoxy-2-propanol, diacetone alcohol, ethyl lactate, butyl lactate, propylene glycol monomethyl ether, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 2-ethoxyethyl acetate, butyl acetate, isoamyl acetate, dimethyl adipate, dimethyl succinate, dimethyl glutarate, tetrahydrofuran, and methylpyrrolidone. Of these, methyl ethyl ketone is preferred. Two or more of these organic solvents may be used in combination. The active energy ray-curable composition of this embodiment may contain, for example, the solvent used when synthesizing each resin. The active energy ray-curable composition of this embodiment may be prepared by mixing inorganic fine particles (A), a solvent, and optional components to prepare an inorganic fine particle (A) dispersion, and then mixing this with the (meth)acrylate (C) according to this embodiment and, if necessary, the photopolymerization initiator (D). When the active energy ray-curable composition of this embodiment contains a solvent, the content of the solvent in the active energy ray-curable composition is preferably 0.1 to 5 mass %, more preferably 0.3 to 3 mass %.

[0059] [Method for Preparing Active Energy Ray-Curable Composition] The method for preparing the active energy ray-curable composition of this embodiment is not particularly limited. For example, a method can be mentioned in which a dispersion of inorganic fine particles (A) is obtained, and then the dispersion of inorganic fine particles (A) is mixed with the (meth)acrylate (C) according to this embodiment, and if necessary, the photoinitiator, other (meth)acrylates, and various other additives. The method for producing the active energy ray-curable composition of this embodiment preferably includes the steps of: preparing a dispersion of inorganic fine particles (A); and mixing the dispersion of inorganic fine particles (A) with the (meth)acrylate (C) according to this embodiment, and if necessary, the photoinitiator, other (meth)acrylates, and various other additives. The mixing method is not particularly limited, and can be, for example, a method using a media-type wet disperser.

[0060] In addition, in the step of preparing a dispersion of inorganic fine particles (A), at least a portion of the (meth)acrylate (C) according to the present embodiment, or at least a portion of the other (meth)acrylates as needed, may be added.

[0061] <Inorganic Fine Particle (A) Dispersion> The inorganic fine particle (A) dispersion according to this embodiment preferably contains, for example, the inorganic fine particles (A), the solvent, and the dispersant (B) as the additive. The inorganic fine particle (A) dispersion according to this embodiment may further contain at least a portion of the (meth)acrylate (C) according to this embodiment, or, if necessary, at least a portion of the other (meth)acrylates. The dispersant (B) preferably has an acid value in the range of 50 to 300 mgKOH / g. Generally, the dispersant (B) easily causes aggregation of inorganic nanoparticles in the system due to interactions between the inorganic fine particles (A) and other resin components contained in the active energy ray-curable composition of this embodiment, resulting in reduced storage stability of the active energy ray-curable composition and reduced transparency of the cured coating film. By using a dispersant (B) with an acid value in the range of 50 to 300 mgKOH / g, a curable composition with excellent stability over time can be obtained, and the cured product will not only have a high refractive index but also excellent light transmittance and scratch resistance. The dispersion of inorganic fine particles (A) according to this embodiment preferably further contains the silane coupling agent (E) as the additive. Functional groups can be introduced onto the surfaces of the inorganic fine particles (A) using the various silane coupling agents (E) described above.

[0062] The method for producing the inorganic fine particle (A) dispersion according to this embodiment is not particularly limited, and examples thereof include a method for producing the dispersion by dispersing raw materials containing the inorganic fine particles (A), the dispersant (B), and, if necessary, the silane coupling agent (E) using a media-type wet disperser.

[0063] The media-type wet disperser used in the production method can be any known one without any limitation, and examples thereof include a bead mill (Star Mill LMZ-015 manufactured by Ashizawa Fine Tech Co., Ltd., Ultra Apex Mill UAM-015 manufactured by Kotobuki Industries Co., Ltd., etc.).

[0064] The media used in the disperser are not particularly limited as long as they are commonly known beads, but preferred examples include zirconia, alumina, silica, glass, silicon carbide, and silicon nitride. The average particle size of the media is preferably 50 to 500 μm, and more preferably 50 to 200 μm. If the particle size is 50 μm or more, the impact force on the raw material powder is appropriate, and dispersion does not require an excessive amount of time. On the other hand, if the particle size of the media is 500 μm or less, the impact force on the raw material powder is appropriate, and therefore an increase in the surface energy of the dispersed particles can be suppressed, and reagglomeration can be prevented.

[0065] Alternatively, the dispersion process time can be shortened by a two-stage method in which large-particle-size media with a large impact force are used in the initial stage of grinding the raw material powder, and then small-particle-size media that are less likely to re-agglomerate are used after the particle size of the dispersed particles has become smaller.

[0066] Furthermore, it is desirable to use media that has been sufficiently polished in order to prevent a decrease in the light transmittance of the resulting dispersion.

[0067] In the production method using the media-type wet disperser, the order in which the raw materials are charged into the disperser is not particularly limited, but by supplying at least the dispersant (B) last, a curable composition excellent in dispersion stability can be obtained using a small amount of dispersant (B). More specifically, a method in which the raw materials other than the dispersant (B) are charged first, and then mixing or pre-dispersion or the like is performed, and then the dispersant (B) is charged last and the main dispersion step is performed can be mentioned.

[0068] After dispersion is complete, various additives may be added depending on the intended use, or volatile components may be removed by distillation, thereby obtaining the curable composition of the present invention.

[0069] Furthermore, the particle diameter (referred to as the average particle diameter) of the inorganic fine particles (A) in the inorganic fine particle (A) dispersion is larger than the average primary particle diameter of the inorganic fine particles (A) that are the raw material for the inorganic fine particle (A) dispersion, because the inorganic fine particles (A) are partially aggregated in the dispersion. Therefore, the average particle diameter of the inorganic fine particles (A) in the inorganic fine particle (A) dispersion is preferably 100 nm or less, and more preferably in the range of 20 to 100 nm, in order to provide a cured product having a high refractive index and excellent light transmittance.

[0070] [Characteristics of Active Energy Ray-Curable Composition] After curing, the active energy ray-curable composition of the present embodiment gives a cured product, which will be described later, that has good light resistance and a high refractive index.

[0071] (Cured Product) The cured product of this embodiment is a cured product of the active energy ray-curable composition of this embodiment described above. The cured product of this embodiment can be used in various applications, such as optical lenses, optical films, antireflection materials, thin-film encapsulating materials, optical pressure-sensitive adhesives, optical adhesives, and diffusion microlenses. The shape of the cured product of this embodiment is not particularly limited, and can be selected depending on the application, such as a flat sheet with a smooth surface, a sheet with a fine uneven structure, or a sheet with a curved surface like a concave or convex lens. The cured product of this embodiment can be thinned when used in optical lenses. In optical films, the difference in refractive index between the transparent electrode and the cured product can be reduced to make the transparent electrode less noticeable, and can be combined with a low refractive index layer to impart antireflection functionality. In LED encapsulants, the refractive index (589 nm) at 25°C is preferably 1.60 to 1.80, more preferably 1.65 to 1.77, from the viewpoint of balancing light extraction efficiency from the light-emitting element and light resistance. A refractive index of 1.68 to 1.75 is even more preferable.

[0072] [Method for Producing Cured Product] The method for producing the cured product of this embodiment is not particularly limited, and may include, for example, a coating step of coating the active energy ray-curable composition of this embodiment onto a substrate such as a transparent film, and a curing step of irradiating the film of the active energy ray-curable composition obtained in the coating step with active energy rays to cure it. As a method for coating the substrate such as a transparent film, a known method can be used, and for example, a method using a rod or wire bar, or various coating methods such as microgravure, gravure, die, curtain, lip, slot, or spin can be used.

[0073] The active energy rays can be used without any particular limitation as long as they are active energy rays that cause curing of the curable composition of the present invention, but it is particularly preferable to use ultraviolet rays.

[0074] Sources of ultraviolet rays include fluorescent chemical lamps, black lights, low-pressure, high-pressure, and ultra-high-pressure mercury lamps, metal halide lamps, and sunlight. For example, an 80 W high-pressure mercury lamp can be used. The irradiation intensity of the ultraviolet rays can be kept constant throughout, or the intensity can be changed during curing to finely adjust the physical properties after curing. For example, when an 80 W high-pressure mercury lamp is used in a nitrogen atmosphere, the ultraviolet rays can be irradiated at 0.5 to 3.0 kJ / m ２ It can be irradiated with an energy value of

[0075] In addition to ultraviolet rays, other active energy rays that can be used include visible light and electron beams.

[0076] (Optical Article or Optical Sheet) The optical article or optical sheet of this embodiment can be formed using the cured product of this embodiment described above. The optical article or optical sheet of this embodiment may include, for example, a substrate and the cured product according to this embodiment formed on the substrate. The optical article or optical sheet of this embodiment may include, for example, a pattern of the cured product of the active energy ray-curable composition of this embodiment. The line width of the cured product pattern may be 50 μm or less. The optical article or optical sheet of this embodiment may include, for example, a fine pattern layer such as a fine uneven structure that is the cured product of the active energy ray-curable composition of this embodiment, and a transparent substrate. Furthermore, the fine pattern layer such as the fine uneven structure may have a fine uneven structure of, for example, 50 nm to 500 μm, 100 nm to 100 μm, or more preferably 200 nm to 50 μm on its surface, depending on the application of the optical article or optical sheet. Furthermore, the cured product of the active energy ray-curable composition in the optical article or optical sheet of this embodiment may have a smooth surface without a fine uneven structure. The shape can be selected appropriately depending on the application.

[0077] Examples of the optical sheet include a polarizing film, a retardation film, an antireflection film, a brightness enhancement film (such as a prism sheet or a microlens sheet), a light diffusion film, and a hard coat film. Examples of the optical article include a microlens, a microlens array, a Fresnel lens, a diffractive optical element, and a light guide plate.

[0078] Examples of optical articles that can be used include lenses and lens arrays such as light extraction layers for OLED displays, lenticular lenses for spatial displays, microlens arrays for in-vehicle HMDs (Head Mounted Displays), focusing lenses for CCD and CMOS sensors, and camera lenses for mobile devices. These microlenses and microlens arrays can bend light by adjusting the refractive index, lens shape, and lens size. Furthermore, they can also be used in diffraction elements and light guide plates provided in display units that realize augmented reality (AR), mixed reality (MR), or virtual reality (VR). These diffraction elements and light guide plates essentially have a pattern layer containing a lattice-shaped nanopattern capable of diffracting light formed on a substrate. Examples of the shape of the pattern structure include rectangular, blazed, and slant shapes. The pattern structure may have a period of, for example, 100 nm or more and 50 μm or less. The composition of this example has a high refractive index, which improves the total internal reflectance of light passing through the waveguide, thereby reducing optical loss and improving the angle at which light can enter and exit the light guide, thereby enabling an improvement in the field of view (FOV). The lenses, lens arrays, diffraction elements, light guide plates, etc. are formed by applying a photocurable resin composition to a substrate and imprinting it using a mold having a surface with various pattern shapes. The formed pattern structure can be used as a sheet, or it can be cut out and used as a single pattern. Methods for applying the photocurable resin composition to a substrate include spin coating, spraying, inkjet printing, (micro)gravure coating, die coater coating, roll coating, and rotary coating.

[0079] [Substrate] Examples of the substrate according to this embodiment include polyethylene terephthalate (PET), triacetyl cellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), polycarbonate, vinyl chloride, polymethacrylimide, polyimide, polyester, acrylic substrates mainly composed of polymethyl methacrylate (PMMA), glass, and silicon wafers. The film thickness of the substrate according to this embodiment is preferably 1 to 300 μm, and more preferably 5 to 100 μm. Specific examples of the substrate according to this embodiment include the 125 μm polyethylene terephthalate (PET) substrate (product name: A4300, manufactured by Toyobo Co., Ltd.) used in the examples.

[0080] When the substrate is transparent, a transparent substrate used in a conventional optical sheet such as a prism sheet can be used. For example, the transparent substrate described in Patent Document 2 can be used. The transparent substrate may be a resin substrate or a glass substrate. Preferred transparent resin substrates include acrylic resin, polycarbonate resin, vinyl chloride resin, polymethacrylimide resin, polyimide resin, polyester resin, cycloolefin polymer (COP) resin, cycloolefin copolymer (COC) resin, and cellulose triacetate (TAC) resin.

[0081] The transparent substrate may be in a long shape or in a sheet shape of a predetermined size. The thickness of the transparent substrate is usually preferably 50 to 500 μm, but is not limited thereto. The light transmittance of the transparent substrate is ideally 100% for installation in front of a display, and preferably 85% or more. The surface of the transparent substrate may be subjected to a conventionally known matte treatment (formation of light-diffusing micro-irregularities), antistatic treatment, antireflection treatment, or the like, as necessary. Furthermore, a matte treatment, antistatic treatment, antireflection treatment, or the like may be applied between the transparent resin and the substrate, or these treatments may be used in any combination.

[0082] [Method for producing optical article or optical sheet] The method for producing the optical article or optical sheet of this embodiment is not particularly limited, and includes, for example, the steps of applying the active energy ray-curable composition of this embodiment to the substrate and irradiating with active energy rays such as ultraviolet rays to form a cured coating film. A method for producing a laminate of this embodiment, for example, includes the steps of applying the active energy ray-curable composition of this embodiment to a triacetyl cellulose substrate film (TAC substrate film) having a thickness of 40 to 100 μm and irradiating the substrate with ultraviolet rays at 0.5 to 3.0 kJ / m using a 60 to 100 W high-pressure mercury lamp under a nitrogen atmosphere. ２ and forming a cured coating film having a thickness of 5 to 20 μm on the TAC substrate film.

[0083] As a method for producing the optical sheet of this embodiment, for example, as shown in Figure 2 of Patent Document (JP 2009-37204 A), the above composition is placed in a mold having a fine pattern shape such as a desired fine uneven structure, a transparent substrate layer is superimposed thereon, the transparent substrate layer is pressed onto the composition using a laminator or the like, and the composition is cured with ultraviolet light or the like to form a fine pattern shape such as a fine uneven structure. Next, the mold having the fine pattern shape is peeled or removed, thereby obtaining an optical sheet having an optical function-exhibiting portion having the desired fine pattern shape on the transparent substrate layer.

[0084] <Prism Sheet> A specific example of the optical article or optical sheet of this embodiment is a prism part or prism sheet. The prism part or prism sheet has, for example, a microrelief structure layer that is a cured product of the active energy ray-curable composition of this embodiment, and a transparent substrate. The microrelief structure layer has a microrelief structure with a period P of 10 to 100 μm on its surface. The thickness of the microrelief structure layer is, for example, 5 μm to 100 μm.

[0085] Usually, since the (meth)acrylate (C) according to the present embodiment is not contained, the light resistance of the cured product tends to be poor. In light of this tendency, in the present invention, when the (meth)acrylate (C) according to the present embodiment is blended with the inorganic fine particles (A), the structure of the (meth)acrylate (C) has a molecular bond that is difficult to photodecompose, and therefore the light resistance is improved.

[0086] As described above, configurations that provide greater effects and the mechanisms by which these effects are thought to be manifested have been explained, but the present invention is not limited to these configurations, and the problems of the present invention can also be solved with compositions that do not contain a silane coupling agent or a phosphate ester-based dispersant, or compositions that do not contain a specific compound as a monofunctional (meth)acrylate.

[0087] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. (Raw Materials) "Inorganic Fine Particles (A)": Zirconia nanoparticles, UEP-100 (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) "Dispersant (B)" (phosphate ester compound): (a compound represented by the following structural formula (4)

[0088]

[0089] (In the formula, R １ is a methyl group, and R ２ is an ethylene chain having 2 carbon atoms, x is 5, y is 1 to 7 (average value), and n is an integer of 1 to 3.

[0090] "Silane coupling agent (E)": KBM-503 (manufactured by Shin-Etsu Chemical Co., Ltd., 3-(trimethoxysilyl)propyl methacrylate)

[0091] "Other (meth)acrylate compounds (F)": Phenol (EO) acrylate Bisphenol A (EO) 10 Dimethacrylate 3-phenoxybenzene acrylate

[0092] "Photopolymerization initiator (D)": 2,4,6-trimethylbenzoyldiphenylphosphine oxide, trade name: Runtecure 1108 (manufactured by Runtec Chemical Co., Ltd.)

[0093] <Film refractive index (594 nm)> The active energy ray-curable resin composition was applied to a 125 μm-thick PET film so that the film thickness after curing would be 6 μm, and the active energy ray-curable resin composition was applied to a 125 μm-thick PET film so that the film thickness after curing would be 6 μm. ２ The refractive index of this flat-film-like cured product was measured at 594 nm using a Metricon Model 2010 prism coupler.

[0094] <Light resistance> The active energy ray-curable resin composition was applied to a 125 μm-thick PET film so that the film thickness after curing would be 6 μm, and the applied composition was exposed to 400 mJ / cm 2 using a Fusion (H-Bulb) light source. ２ The flat-film cured product was cured by irradiating it with ultraviolet light of 1000 nm to produce a flat-film cured product. The flat-film cured product was subjected to a light resistance test using an Atlas Ci4000, and the film thickness (nm) due to photodegradation was measured using an interference microscope. Yellowing was also evaluated using a SpectroEye spectrophotometer (manufactured by X-rite) (light source: D65, observation field: 10°). The b value is the L defined by the CIE (Commission Internationale de l'Eclairage). ＊ a ＊ b ＊ b in the color system ＊ This is the value obtained by measuring

[0095] <Nanoimprintability> An active energy ray-curable resin composition was applied to a substrate, and held for 60 seconds while applying a pressure of 100 N using a quartz mold (350 nm L&S). Thereafter, a high-pressure mercury lamp was used to apply 500 mJ / cm ２ After the exposure, the mold was released.

[0096] "Measurement conditions" Lamp: Xe 7500W Illuminance: 130 Temperature inside the layer: 40°C Measurement time: 96 hours

[0097] "Criteria for determining film loss" ◎: Film thickness after test is 95% or more of the initial film thickness 〇: Film thickness after test is 85% or more of the initial film thickness ×: Film thickness after test is less than 85% of the initial film thickness

[0098] "Criteria for yellowing evaluation": ◎: b value after test is less than 3; ○: b value after test is 3 or more and 10 or less; △: b value after test is more than 10

[0099] "Criteria for nanoimprint pattern SEM observation" ○: No pattern defects, pattern formed exactly as mold shape ×: Pattern defects

[0100] Example 1 44.0 parts by mass of UEP-100 as zirconia, 7.0 parts by mass of phosphoric acid ester 1 (dispersant B-1) as a phosphate ester, 4.0 parts by mass of KBM-503 as a silane coupling agent, and 100 parts by mass of methyl ethyl ketone (hereinafter abbreviated as "MEK") were mixed and stirred for 30 minutes with a dispersion stirrer to perform coarse dispersion. Next, the resulting mixture was dispersed using zirconia beads with a particle size of 100 μm in a media-type wet disperser ("Star Mill LMZ-015" manufactured by Ashizawa Finetech Co., Ltd.). The dispersion process was performed for a residence time of 100 minutes while checking the particle size during the process, and an inorganic fine particle dispersion was obtained. To this inorganic fine particle dispersion, 12.0 parts by mass of tricyclodecane dimethanol diacrylate (manufactured by Daicel Corporation) was added as the (meth)acrylate (C) according to this embodiment, and the volatile components were removed under reduced pressure while heating in an evaporator. Furthermore, 3 parts by mass of Runtecure-1104 (manufactured by Runtec Corporation) was added as a photopolymerization initiator to prepare an active energy ray-curable composition P1 (composition P1) according to this embodiment. The solids content was evaluated using the evaluation methods described above. Furthermore, the film refractive index, film loss, yellowing, and nanoimprintability of the cured product of composition P1 were evaluated. The results are shown in Table 1.

[0101] (Examples 2 to 4, Comparative Example 1) In each example, compositions P2 to P4 and cP1 of Examples 2 to 4 and Comparative Example 1 were prepared in the same manner as Example 1, except that the components and compositional ratios shown in Table 1 were used. The amount of MEK used was 2.15 times the amount of inorganic fine particles shown in Table 1, as in Example 1. The solid content of each composition was evaluated as in Example 1. In addition, the film refractive index, film loss, yellowing, and nanoimprintability of the cured product of each composition were evaluated. The results are shown in Table 1.

[0102]

[0103] In the table, the meaning of each item is as follows:

[0104] (A): Inorganic fine particles (A) Zirconia nanoparticles, product name: UEP-100 (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.)

[0105] (B): Dispersant (B) A compound represented by the above structural formula (4)

[0106] (E): Silane coupling agent (E) KBM-503: 3-(trimethoxysilyl)propyl methacrylate, trade name: KBM-503 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0107] (C): (Meth)acrylate (C) according to this embodiment Tricyclodecane dimethanol diacrylate: trade name EBECRYL 130 (manufactured by Daicel Corporation) Isobornyl methacrylate: trade name Light Ester IB-X (Kyoeisha Chemical Co., Ltd.)

[0108] (F): Other (meth)acrylates (not belonging to the (meth)acrylate (C) according to this embodiment) o-Phenylphenol (EO) acrylate: Trade name KOMERATE A011 (manufactured by Green Chemical Co., Ltd.) Biphenyl methyl acrylate: Trade name Miramer 1192 (manufactured by MIWON Co., Ltd.) MEK: Methyl ethyl ketone, Trade name Methyl Ethyl Ketone (manufactured by Yamaichi Chemical Co., Ltd.)

[0109] (D): Photopolymerization initiator (D) Runtecure-1104 (manufactured by Runtec)

[0110] (Discussion) From the results of the above examples, it can be seen that the light resistance is improved by adding a structure of (meth)acrylate (C) that is resistant to photodecomposition. Preferably, the light resistance is enhanced by adding 10 mass % or more of the total solid content, and the composition can be used particularly for HMDs used outdoors, camera lenses, diffraction elements of smart glasses, and light guide plates.

Claims

1. An active energy ray-curable composition containing inorganic fine particles (A), a dispersant (B), and a (meth)acrylate having an aliphatic cyclic structure (C), The dispersant (B) is represented by the following structural formula (4): The active energy ray-curable composition has a film refractive index of 1.60 to 1.75 when cured. 【Chemical 1】 (In the formula, R 1 is a hydrogen atom or a methyl group, R 2 is an alkylene chain having 2 to 4 carbon atoms, x is an integer of 4 to 10, y is an integer of 1 or more, and n is an integer of 1 to 3.)

2. 2. The active energy ray-curable composition according to claim 1, wherein the inorganic fine particles (A) are at least one selected from the group consisting of zirconia, titania, niobium oxide, and barium titanate.

3. 2. The active energy ray-curable composition according to claim 1, wherein the (meth)acrylate (C) having an aliphatic cyclic structure is a compound having at least one selected from the group consisting of structures represented by the following general formulas (1) and (2): 【Chemistry 2】 【Chemistry 3】 【Chemistry 4】 (General formula (1), (2), (3), middle, R １ , R ２ , R ５ , R ７ are each independently a hydrogen atom or a methyl group. ３ , R ４ are each independently a direct bond methylene group or an ethylene oxide chain having 4 or less repeating units. ６ , R ８ is a directly bonded oxygen atom or an ethylene oxide chain of 4 or less repeating units.

4. The active energy ray-curable composition according to any one of claims 1 to 3, further comprising a photopolymerization initiator (D).

5. An optical article or optical sheet comprising a pattern of a cured product of the active energy ray-curable composition according to claim 4.

6. 6. The optical article or optical sheet according to claim 5, wherein the line width of the cured product pattern is 50 μm or less.

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