Active energy ray curable composition, 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

[Technical Field]

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

[0002] In recent years, optical sheets that provide functions such as improved brightness and expanded viewing angles have been used in displays such as liquid crystal displays. Furthermore, optical sheets and optical articles are used in HMDs (Head Mounted Displays) 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 consist of a substrate and an optical functional layer having a fine uneven structure on the substrate. The desired function is achieved by modulating light through geometric optics and wave optics such as refraction and diffraction at the uneven shape. The material used in the optical functional layer requires a high refractive index. To address this, methods have been proposed that involve using (meth)acrylates with a high refractive index or adding organic or inorganic high refractive index fine particles (for example, Patent Documents 1-3). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2020 / 250721 [Patent Document 2] Japanese Patent Publication No. 2013-249439 [Patent Document 3] Japanese Patent Publication No. 2010-85539 [Overview of the Initiative]

Problems to be Solved by the Invention

[0004] However, these optical sheets had a problem that the light resistance was insufficient, and film reduction and yellowing due to light irradiation occurred. Therefore, a material having good light resistance and a high refractive index has been demanded.

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

Means for Solving the Problems

[0006] The present invention has reached a patent application because it has been found that by setting the content of monofunctional (meth)acrylate in the (meth)acrylate compound within a specific range and blending inorganic fine particles at a certain level or more, a high refractive index can be achieved and good light resistance can be exhibited. The content of 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 aliphatic cyclic structure, wherein the film refractive index of the 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 aliphatic cyclic structure is a compound having at least one selected from the group consisting of the structures represented by the following general formulas (1) and (2).

Chemical formula

Chemical formula

Chemical formula

[0010] , , , R 2 , R 5 , R 7 is each independently a hydrogen atom or a methyl group. R 3 , R 4 is each independently a methylene group with a direct bond or an ethylene oxide chain having 4 or less repeating units. R 6 , R 8 is an oxygen atom with a direct bond 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 an optical sheet including a cured product pattern of the active energy ray curable composition according to [4]. [6] The optical article or the optical sheet according to [5], wherein the line width of the cured product pattern is 50 μm or less. [Advantages of the Invention]

[0007] According to the present invention, it is possible to provide an active energy ray curable composition, an optical article, or an optical sheet having good light resistance and a high refractive index. [Modes for Carrying Out the Invention] '

[0008] Hereinafter, the present invention will be described in more detail. Note that the present invention is not limited only to the embodiments shown below.

[0009] "~" means not less than the value before the description of "~" and not more than the value after the description of "~". "(Meth)acryl" 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 an aliphatic cyclic structure (meth)acrylate (C), and the refractive index of the cured product of the active energy ray curable composition is 1.60 to 1.75.

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

[0012] The inorganic fine particles (A) in this embodiment can be any commonly known type, and the shape of the particles is not particularly limited, but may be spherical, hollow, porous, rod-shaped, plate-shaped, fibrous, or amorphous. Among these, spherical particles are preferred because they have excellent dispersion stability and yield a cured product with high light transmittance and refractive index.

[0013] <Zirconia nanoparticles> The inorganic fine particles (A) in this embodiment are more preferably zirconia nanoparticles. The zirconia nanoparticles can be those that are generally known, and the particle shape is not particularly limited, but examples include spherical, hollow, porous, rod-shaped, fibrous, etc., and among these, spherical is preferred. Furthermore, the average primary particle size of the zirconia nanoparticles according to this embodiment is preferably 1 to 50 nm, and more preferably 1 to 30 nm. In addition, the crystal structure is not particularly limited, but a monoclinic system is preferred. In this invention, the average primary particle diameter can be measured by directly measuring the size of the primary particles from electron microscope images using a TEM (transmission electron microscope). One such measurement method involves measuring the short-axis diameter and long-axis diameter of the primary particles of individual inorganic microparticles and taking their average as the average primary particle diameter. Specific examples of zirconia nanoparticles according to this embodiment include UEP-100 (average primary particle diameter: 11 nm) manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd., and PCS (average primary particle diameter: 20 nm) manufactured by Nippon Denko Co., Ltd.

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

[0015] [Dispersant (B)] The dispersant (B) (sometimes referred to as "component (B)") contained in the active energy ray curable composition of this embodiment is essentially composed of 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) with a molecular weight of 250 or less. It is preferable that the dispersant (B) contains the phosphate ester compound (b1) including the above phosphate ester.

[0016] <Phosphate ester compound (b1)> The phosphate ester compound (b1) according to this embodiment is not particularly limited, but for example, those having a polyester chain include DISPERBYK-110 and DISPERBYK-111 (manufactured by BIC Chemie Japan Co., Ltd.).

[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. However, as those having a (meth)acryloyl group, for example, since the obtained inorganic particle dispersion has excellent dispersion stability, and the curable composition containing the same has light resistance and can form a cured coating film having high refractive index performance, those represented by the following structural formula (4) can be mentioned.

[0018] [Chemical formula] (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. Also, 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] Since the phosphate ester compound represented by the above structural formula (4) can form a cured coating film having high refractive index performance and light resistance in the obtained active energy ray curable composition, x in the formula is preferably 4 or 5, and y is preferably an integer of 1 to 7. Also, in the dispersant (B) represented by the above structural formula (4), n in the formula may be a mixture of 1, 2 and / or 3.

[0020] <Hydroxyl group-containing compound (b2)> As the hydroxyl group-containing compound (b2), those having a molecular weight of 250 or less are 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] Furthermore, as the hydroxyl group-containing compound (b2), hydroxyl group-containing (meth)acrylate compounds such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trimethylolpropane (meth)acrylate, and pentaerythritol acrylate; (poly)oxyalkylene modified compounds obtained by introducing (poly)oxyalkylene chains such as (poly)oxyethylene chains, (poly)oxypropylene chains, and (poly)oxytetramethylene chains into the molecular structure of the hydroxyl group-containing (meth)acrylate compound; and lactone modified compounds obtained by introducing a (poly)lactone structure into the molecular structure of the hydroxyl group-containing (meth)acrylate compound can also be used.

[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 it has low viscosity, allowing for the formation of a cured coating film with 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, and more preferably in the range of 0.1 to 20 parts by mass, per 100 parts by mass of the phosphate ester compound (b1), in order that the resulting inorganic fine particle dispersion has excellent dispersion stability, and the curable composition containing it has low viscosity, high refractive index performance, and excellent bleed-out resistance to form a cured coating film.

[0025] As necessary, other dispersants may be used in combination with the aforementioned dispersant (B).

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

[0027] In the active energy ray curable composition, the content of the dispersant (B) 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, in order to form a cured coating film having high refractive index performance and excellent light resistance.

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

[0029] [ka] [ka] [ka]

[0030] (General formulas (1), (2), (3), medium, R 1 , R 2 , R 5 , R 7 Each of these is independently a hydrogen atom or a methyl group. 3 , R 4 Each of these is independently a directly bonded methylene group or an ethylene oxide chain with 4 or fewer repeating units. 6 , R 8 (This refers to an oxygen atom directly bonded, or an ethylene oxide chain with 4 or fewer repeating units.)

[0031] <(meth)acrylate (C1)> (Meth)acrylate(C) having the structure represented by the above general formula (1) (hereinafter sometimes referred to as (meth)acrylate(C1)) is, in the above general formula (1), R 1 , R 2 Each of these is preferably a hydrogen atom or a methyl group. 3 , R 4 Each of these is preferably an independent methylene group or an ethylene oxide group with 4 or fewer repeating units, and more preferably a methylene group or an ethylene oxide group with 2 or fewer repeating units.

[0032] Examples of the (meth)acrylate (C1) in this embodiment include tricyclodecanedimethanol diacrylate and tricyclodecanedimethanol dimethacrylate.

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

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

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

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

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

[0038] Furthermore, the (meth)acrylate (C) according to this embodiment does not contain a dispersant (B) having a (meth)acryloyl group, or a silane coupling agent (E) having a (meth)acryloyl group and 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 the polymerization of (meth)acryloyl groups such as (meth)acrylate (C) according to this embodiment by photoexcitation. Examples include intramolecular bond cleavage type photopolymerization initiators (D) and intramolecular hydrogen abstraction type photopolymerization initiators (D). For example, monocarbonyl compounds, dicarbonyl compounds, acetophenone compounds, benzoin ether compounds, acylphosphine oxide compounds, aminocarbonyl compounds, etc., can be used.

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

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

[0042] Examples of commercially available photopolymerization initiators (D) include "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", "Omnirad 4-MBZ", "Omnirad 1314", "Esacure KT55", "Esacure TZT", "Eascure ONE", "LFC4563", Omnipol BP, Omnipol Examples include ASA, Omnipol 910, Omnipol TP (manufactured by IGM), Kayacure-DETX, Kayacure-MBP, Kayacure-DMBI, Kayacure-EPA, Kayacure-OA (manufactured by Nippon Kayaku Co., Ltd.), Bycure-10, Bycure-55 (manufactured by Stauffa Chemicals), Trigonal P1 (manufactured by Akzo), Sandoz 1000 (manufactured by Sandoz), Deep (manufactured by Apjon), Quantacure-PDO, Quantacure-ITX, Quantacure-EPD (manufactured by Ward Blenkinsop), Runtecure-1104 (manufactured by Runtec), and Darocur MBF (manufactured by BASF). These photopolymerization initiators can be used individually or in combination of two or more.

[0043] The photopolymerization initiator (D) is not limited to the above-mentioned compound, but can be any substance that has the ability to initiate polymerization by ultraviolet light. These photopolymerization initiators (D) may be used individually or in combination of two or more types. There are no particular restrictions on the amount of the photopolymerization initiator (D) used, but it is preferable to use it in the range of 0.1 to 10 parts by mass, and more preferably in the range of 1 to 5 parts by mass, per 100 parts by mass of the solid content (non-volatile content) of the active energy ray curable composition of this embodiment. Known organic amines and the like can also be added as sensitizers. Furthermore, in addition to the radical polymerization initiators mentioned above, cationic polymerization initiators can also be used in combination. The solid content (non-volatile content) mass of the composition refers to the total mass of all components of the composition after removing 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 this embodiment may optionally further contain a silane coupling agent (E) (sometimes referred to as "component (E)"). Examples of the silane coupling agent (E) according to this embodiment include (meth)acryloyloxy silane coupling agents such as 3-(meth)acryloyloxypropyltrimethylsilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, and 3-(meth)acryloyloxypropyltriethoxysilane; Vinyl silane coupling agents such as allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane, trichlorovinylsilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(2-methoxyethoxy)silane; Epoxy 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-dimethylbutylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane; Ureidopropyltriethoxysilane and other ureido-based silane coupling agents; Chloropropyl silane coupling agents such as 3-chloropropyltrimethoxysilane; mercapto-silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; Sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide; Isocyanate-based silane coupling agents such as 3-isocyanate-propyltriethoxysilane; Examples include aluminum-based silane coupling agents such as acetalkoxyaluminum 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 inorganic fine particles (A), in order that the resulting active energy ray curable composition has excellent dispersion stability, is lightfast, and can form a cured coating film with high refractive index performance.

[0045] [Other (meth)acrylates (F)] The active energy ray curable composition according to this embodiment may also contain, for example, the following monofunctional (meth)acrylates or polyfunctional (meth)acrylates (F) (sometimes referred to as "component (F)") that do 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-like aliphatic or cyclic alicyclic or aromatic (meth)acrylate containing heteroatoms such as halogen atoms, sulfur atoms, oxygen atoms, or nitrogen atoms. For example, the monofunctional (meth)acrylate described in Patent Document 1 above 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. Furthermore, examples of the monofunctional (meth)acrylate include polyoxyalkylene-modified mono(meth)acrylate compounds obtained by introducing polyoxyalkylene chains such as polyoxyethylene chains, polyoxypropylene chains, and polyoxytetramethylene chains into the molecular structure of the various mono(meth)acrylate compounds; and lactone-modified mono(meth)acrylate compounds obtained by introducing a (poly)lactone-derived structure into the molecular structure of the various mono(meth)acrylate compounds.

[0048] Examples of the aromatic mono(meth)acrylate compounds 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 compounds 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, adamantylmono(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 tetrahydrofurfurylacrylate. 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 compound include caprolactone-modified tetrahydrofurfuryl(meth)acrylate.

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

[0051] <Multifunctional (meth)acrylate>

[0052] The polyfunctional (meth)acrylate is preferably a polyfunctional (meth)acrylate having three or more active energy ray curable groups. It may also be a chain-like aliphatic or cyclic alicyclic or aromatic (meth)acrylic acrylate containing heteroatoms such as halogen atoms, sulfur atoms, oxygen atoms, or nitrogen atoms. For example, the polyfunctional (meth)acrylate described in Patent Document 1 above can be used.

[0053] Examples of the polyfunctional (meth)acrylates 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, and 1,6-hexanediol di(meth)acrylate. Rate, 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 hydroxypivalate neopentyl glycol di(meth)acrylate, tetrabromobisphenol A di(meth)acrylate, hydropivalaldehyde modified trimethylolpropane di(meth)acrylate, bisphenol fluoren (meth)acrylate, bisphenol fluorene (EO) n Di(meth)acrylate, bisphenol A(EO) n Di(meth)acrylate, trimethylolpropane (EO) n Examples of polyfunctional (meth)acrylates include 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, and polyester(meth)acrylate.

[0054] These polyfunctional (meth)acrylates can be used individually or in combination of two or more. Among these, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, ditrimethylolpropanetetra(meth)acrylate, reaction products of pentaerythritol and acrylic acid, and reaction products of dipentaerythritol and acrylic acid are preferred because they yield (meth)acrylic resins with excellent drying properties, ink flowability, and suitability for high-speed printing.

[0055] <Other additives>

[0056] The composition of the present invention may optionally contain other additives. Examples of such other additives include photosensitizers, ultraviolet absorbers, antioxidants, silicone-based additives, fluorine-based additives, rheology control agents, defoaming agents, 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 photosensitizers 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-benzylisothironium-p-toluenesulfonate. These photosensitizers can be used alone or in combination of two or more. When adding these photosensitizers, the amount added is preferably in the range of 0.01 to 10% by mass in the composition. Adding photosensitizers 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. Specifically, 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, methylpyrrolidone, and the like. Among these, methyl ethyl ketone is preferred. These organic solvents can be used in combination of two or more types. The active energy ray curable composition of this embodiment may, for example, include the solvent used in synthesizing each resin. Furthermore, the active energy ray curable composition of this embodiment may be prepared by mixing inorganic fine particles (A), a solvent, and an optional component to prepare a dispersion of inorganic fine particles (A), and then mixing it with the (meth)acrylate (C) according to this embodiment and, if necessary, a photopolymerization initiator (D). When the active energy ray curable composition of this embodiment contains a solvent, the solvent content in the active energy ray curable composition is preferably 0.1 to 5% by mass, and more preferably 0.3 to 3% by mass.

[0059] [Method for preparing an active energy ray-curable composition] The method for preparing the active energy ray curable composition of this embodiment is not particularly limited. For example, one method is to obtain a dispersion of inorganic fine particles (A), and then mix the dispersion of inorganic fine particles (A), the (meth)acrylate (C) according to this embodiment, and optionally the photoinitiator, other (meth)acrylates, and various other additives. A method for producing the active energy ray curable composition of this embodiment preferably includes the steps of: preparing an inorganic fine particle (A) dispersion; and mixing the inorganic fine particle (A) dispersion, the (meth)acrylate (C) according to this embodiment, and optionally a photoinitiator, other (meth)acrylates, and various other additives. The mixing method is not particularly limited, but one example is the use of a media-type wet disperser.

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

[0061] <Inorganic fine particle (A) dispersion> The inorganic fine particle (A) dispersion according to this embodiment preferably comprises, for example, the inorganic fine particle (A), the solvent, and the dispersant (B) as an additive. The inorganic fine particle (A) dispersion according to this embodiment may further comprise at least a portion of the (meth)acrylate (C) according to this embodiment, or, if necessary, at least a portion of the other (meth)acrylate. The dispersant (B) preferably has an acid value in the range of 50 to 300 mgKOH / g. Generally, with the dispersant (B), inorganic nanoparticles (A) tend to aggregate within the system due to interactions between the inorganic nanoparticles (A) and other resin components contained in the active energy ray curable composition of this embodiment, which can lead to a decrease in the storage stability of the active energy ray curable composition and a decrease in the 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 long-term stability can be obtained, and the cured product will not only have a high refractive index but also excellent light transmittance and scratch resistance. The inorganic fine particle (A) dispersion according to this embodiment more preferably further contains the silane coupling agent (E) as an additive. Functional groups can be introduced to the surface of the inorganic fine particle (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, but examples include a method of producing it by dispersing raw materials containing the inorganic fine particle (A), the dispersant (B), and optionally the silane coupling agent (E) in a media-type wet disperser.

[0063] The media-type wet disperser used in the above manufacturing method can be any commonly known type without limitation, such as a bead mill (e.g., Star Mill LMZ-015 manufactured by Ashizawa Finetech Co., Ltd., Ultra Apex Mill UAM-015 manufactured by Kotobuki Kogyo Co., Ltd.).

[0064] The media used in the disperser is not particularly limited as long as it is a commonly known bead, but zirconia, alumina, silica, glass, silicon carbide, and silicon nitride are preferred. The average particle size of the media is preferably 50 to 500 μm, and media of 50 to 200 μm is more preferred. If the particle size is 50 μm or larger, the impact force on the raw material powder is appropriate, and dispersion does not require excessive time. On the other hand, if the particle size of the media is 500 μm or smaller, the impact force on the raw material powder is appropriate, so the increase in surface energy of the dispersed particles can be suppressed, and re-aggregation can be prevented.

[0065] Furthermore, the dispersion process time can be shortened by using a two-stage method: first, using a large-particle media with high impact force in the initial stages of grinding the raw material powder, and then, once the particle size of the dispersed particles has decreased, using a small-particle media that is less prone to re-aggregation.

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

[0067] In the manufacturing method using the media-type wet disperser, the order in which the raw materials are loaded into the disperser is not particularly limited, but by supplying the dispersant (B) last, a curable composition with excellent dispersion stability can be obtained using only a small amount of dispersant (B). More specifically, a method can be used in which the raw materials other than the dispersant (B) are loaded first, mixed or pre-dispersed, and then the dispersant (B) is loaded last to perform the main dispersion process.

[0068] After dispersion is complete, the curable composition of the present invention can be obtained by adding various additives or removing volatile components by distillation, depending on the application.

[0069] Furthermore, the particle size (average particle size) of the inorganic fine particles (A) in the inorganic fine particles (A) dispersion is larger than the average primary particle size of the inorganic fine particles (A) that are the raw materials for the inorganic fine particles (A) dispersion, because some of the inorganic fine particles (A) are aggregated in the dispersion. Therefore, the average particle size 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, since this results in a cured product with a high refractive index and excellent light transmittance.

[0070] [Properties of Active Energy Ray Curable Compositions] The active energy ray curable composition of this embodiment yields a cured product, described later, that has good light resistance and a high refractive index after curing.

[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 a variety of applications, such as optical lenses, optical films, anti-reflective materials, thin film sealing materials, optical adhesives, optical bonding agents, and diffusion microlenses. Furthermore, the shape of the cured product in this embodiment is not particularly limited and can be selected according to 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 allows for thinning when used in optical lenses, reduces the refractive index difference with transparent electrodes in optical films, makes the transparent electrodes less noticeable, provides anti-reflective properties when combined with a low refractive index layer, and, in LED encapsulants, has a refractive index (589nm) at 25°C of preferably 1.60 or more and 1.80 or less, more preferably 1.65 or more and 1.77 or less, and even more preferably 1.68 or more and 1.75 or less, from the viewpoint of balancing light extraction efficiency from the light-emitting part and light resistance.

[0072] [Method for manufacturing hardened products] The method for producing the cured product of this embodiment is not particularly limited and includes, for example, a coating step of applying 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 for the coating method on a substrate such as a transparent film, known methods can be used, such as methods using a lot or wire bar, or various coating methods such as microgravure, gravure, die, curtain, lip, slot, or spin.

[0073] The aforementioned active energy ray can be any active energy ray that causes the curable composition of the present invention to harden, but ultraviolet light is particularly preferred.

[0074] Sources of ultraviolet light include fluorescent chemical lamps, black lights, low-pressure, high-pressure, and ultra-high-pressure mercury lamps, metal halide lamps, and sunlight. For example, an 80W high-pressure mercury lamp can be used. The UV irradiation intensity can be kept constant throughout the curing process, or it can be varied during the curing process to fine-tune the physical properties after curing. For example, when using an 80W high-pressure mercury lamp under a nitrogen atmosphere, the UV irradiation intensity can be 0.5 to 3.0 kJ / m³. 2 It can be irradiated with this energy value.

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

[0076] (Optical articles or optical sheets) 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 of this embodiment formed on the substrate. The optical article or optical sheet of this embodiment may, for example, include a cured product pattern 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 have, for example, a fine pattern layer such as a fine uneven structure which is a 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, for example, a fine uneven structure of 50 nm to 500 μm, 100 nm to 100 μm, and 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 does not have a fine uneven structure, but may have a smooth surface. The shape can be appropriately selected according to various applications.

[0077] Examples of the optical sheets include polarizing films, phase difference films, anti-reflective films, brightness-enhancing films (prism sheets, microlens sheets, etc.), light-diffusing films, and hard-coat films. Examples of the optical articles include microlenses, microlens arrays, Fresnel lenses, diffractive optical elements, and light guide plates.

[0078] As optical articles, these materials can be used in light extraction layers for OLED displays, lenticular lenses for spatial displays, microlens arrays for HMDs (Head Mounted Displays) used in vehicles, focusing lenses for CCD and CMOS sensors, and lenses and lens arrays for mobile devices. Such microlenses and microlens arrays can bend light depending on the material refractive index, lens shape, and lens size. Furthermore, they can be used as diffracting elements and light guide plates in display units that realize augmented reality (AR), mixed reality (MR), or virtual reality (VR). Such diffracting elements and light guide plates basically have a pattern layer formed on a substrate that includes a grid-like nanopattern that can diffract light. Examples of the shape of the pattern structure include rectangle, blazed, and slant. The pattern structure can also have a period of, for example, 100 nm to 50 μm. Because the composition of this embodiment has a high refractive index, it improves the total internal reflectivity of light passing through the waveguide, thereby reducing light loss. Furthermore, by improving the angle at which light can enter and exit the light guide, it enables an improvement in the field of view (FOV). The aforementioned lenses, lens arrays, diffracting elements, light guide plates, etc., are formed by applying a photocurable resin composition to a substrate and imprinting 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 the substrate include spin coating, spray coating, inkjet coating, (micro)gravure coating, die coating, roll coating, and rotary coating.

[0079] [Base material] Examples of substrates used in 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 in 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, for example, the 125 μm polyethylene terephthalate (PET) substrate (product name: A4300, manufactured by Toyobo Co., Ltd.) used in the example.

[0080] If the substrate is transparent, a transparent substrate used in conventionally known optical sheets such as prism sheets 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 and cycloolefin copolymer (COC) resin, and cellulose triacetate (TAC) resin.

[0081] The transparent substrate may be in the form of a long, rectangular piece, or it may be in the form of a single sheet of a predetermined size. The thickness of the transparent substrate is usually preferably 50 to 500 μm, but is not limited thereto. For the transparent substrate, an ideal light transmittance is 100% for front-mount installation on a display, and a transmittance of 85% or higher is preferable. The transparent substrate may, if necessary, have its surface treated with a conventionally known matte finish (formation of light-diffusing micro-irregularities), an antistatic treatment, or an anti-reflective treatment. Alternatively, a matte finish, antistatic treatment, or anti-reflective treatment may be applied between the transparent resin and the substrate, or these may be used in any combination.

[0082] [Method for manufacturing optical articles or optical sheets] The method for manufacturing the optical article or optical sheet of this embodiment is not particularly limited and may include, for example, the steps of applying the active energy ray curable composition of this embodiment to a substrate and irradiating it with active energy rays such as ultraviolet light to form a cured coating film. The method for manufacturing the laminate of this embodiment may include, for example, the steps of applying the active energy ray curable composition of this embodiment to a triacetylcellulose substrate film (TAC substrate film) with a thickness of 40 to 100 μm and irradiating it with ultraviolet light at a rate of 0.5 to 3.0 kJ / m² using a 60 to 100 W high-pressure mercury lamp under a nitrogen atmosphere. 2 Preferably, the step includes irradiating to form a cured coating film with a thickness of 5 to 20 μm on a TAC substrate film.

[0083] As a method for manufacturing the optical sheet of this embodiment, for example, as shown in Figure 2 of the Patent Document (Japanese Patent Application Publication No. 2009-37204), the above composition is placed in a mold with a desired fine pattern shape, such as a fine uneven structure, a transparent substrate layer is placed on top, 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. Then, by peeling or removing the mold with the fine pattern shape, an optical sheet is obtained that has an optical function manifesting part 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 component or prism sheet. The prism component or prism sheet comprises, for example, a finely textured layer which is a cured product of the active energy ray curable composition of this embodiment, and a transparent substrate. The finely textured layer has a finely textured structure on its surface with a period P of 10 to 100 μm. The thickness of the finely textured layer is, for example, 5 μm to 100 μm.

[0085] Normally, cured products tend to have poor light resistance because they do not contain (meth)acrylate (C) as described in this embodiment. Focusing on this tendency, in the present invention, when the (meth)acrylate (C) according to this embodiment is blended with inorganic fine particles (A), the light resistance is improved because the structure of (meth)acrylate (C) has molecular bonds that are less susceptible to photodegradation.

[0086] As described above, a configuration that yields a more effective result and the mechanism by which these effects are thought to be achieved have been explained. However, 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 and a phosphate ester dispersant, or with compositions that do not contain a specific compound as a monofunctional (meth)acrylate. [Examples]

[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 nanoparticles (A)": Zirconia nanoparticles, UEP-100 (manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd.) "Dispersant (B)" (phosphate ester compound): (a compound represented by structural formula (4) below)

[0088] [ka]

[0089] (In the formula, R1 is a methyl group, R 2 (where is an ethylene chain with 2 carbon atoms, x is 5, y is 1-7 (average value), and n is an integer from 1-3)

[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 BisphenolA(EO)10Dimethacrylate 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 (594nm)> An active energy ray-curable resin composition was applied to a 125 μm thick PET film so that the cured film thickness would be 6 μm, and then exposed to a Fusion (H-Bulb) light source at 400 mJ / cm². 2 A flat, cured film was obtained by irradiating it with ultraviolet light. The refractive index of this flat, cured film at 594 nm of a Metricon Model 2010 prism coupler was measured.

[0094] <Lightfastness> An active energy ray-curable resin composition was applied to a 125 μm thick PET film so that the cured film thickness would be 6 μm, and then exposed to a Fusion (H-Bulb) light source at 400 mJ / cm². 2 A flat, cured film was prepared by curing the material by irradiating it with ultraviolet light. Flat-film cured samples were subjected to lightfastness tests using an Atlas Ci4000 microscope, and the film thickness loss (nm) due to photodegradation was measured using an interference microscope. Yellowing was evaluated using a SpectroEye spectrophotometer (X-rite) (light source: D65, field of view: 10°). The b-value was defined according to the L-value specified by the CIE (International Commission on Illumination). * a * b * b in the color system * This is a value obtained by measuring [something].

[0095] <Nanoimprintability> An active energy ray-curable resin composition was applied to a substrate and held under 100N pressure for 60 seconds using a quartz mold (350nm L&S). Subsequently, 500 mJ / cm² was applied using a high-pressure mercury lamp. 2 After exposure, the mold was demolded.

[0096] "Measurement conditions" Lamp: Xe 7500W Illuminance: 130 Inner temperature: 40℃ Measurement time: 96h

[0097] "Criteria for determining film thinning" ◎: Film thickness after testing is 95% or more of the initial film thickness. ○: Film thickness after testing is 85% or more of the initial film thickness. ×: Film thickness after testing is less than 85% of the initial film thickness.

[0098] "Criteria for determining yellowing": ◎: The b-value after the test is less than 3 ○: The b value after the test is between 3 and 10. △: The b-value after the test is greater than 10

[0099] "Criteria for Judging Nanoimprint Pattern SEM Observation" ○: No pattern defects, and the pattern is formed exactly as per the mold shape. ×: Pattern defect present

[0100] (Example 1) As zirconia, UEP-100, 44.0 parts by mass, As a phosphate ester, 7.0 parts by mass of phosphate ester 1 (dispersant B-1) and As a silane coupling agent, 4.0 parts by mass of KBM-503 and 100 parts by mass of methyl ethyl ketone (hereinafter abbreviated as "MEK") and The mixture was stirred in a dispersion stirrer for 30 minutes to achieve coarse dispersion. Next, the resulting mixture was dispersed using a media-type wet disperser (Star Mill LMZ-015, manufactured by Ashizawa Fine Tech Co., Ltd.) with zirconia beads having a particle size of 100 μm. The dispersion process was carried out with a residence time of 100 minutes while checking the particle size at each stage to obtain an inorganic fine particle dispersion. This inorganic fine particle dispersion, In this embodiment, 12.0 parts by mass of tricyclodecanedimethanol diacrylate (manufactured by Daicel Corporation) was added as (meth)acrylate (C), and volatile components were removed under reduced pressure while heating in an evaporator. Furthermore, Three parts by mass of Runtecure-1104 (manufactured by Runtec) were added as a photopolymerization initiator to prepare the active energy ray curable composition P1 (composition P1) of this embodiment. The solid content was evaluated using the evaluation method described above. The refractive index, film loss, yellowing, and nanoimprintability of the cured product of composition P1 were also evaluated. The results are shown in Table 1.

[0101] (Examples 2-4, Comparative Example 1) Each example prepared compositions P2-P4 and cP1 of Examples 2-4 and Comparative Example 1 in the same manner as Example 1, except that the components and composition 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 in the same manner as in Example 1. In addition, the refractive index, film loss, yellowing, and nanoimprintability of the cured products of each composition were evaluated. The results are shown in Table 1.

[0102] [Table 1]

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

[0104] (A): Inorganic fine particles (A) Zirconia nanoparticles, product name: UEP-100 (manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd.)

[0105] (B): Dispersant (B) 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 Tricyclodecanedimethanol diacrylate: Product name EBECRYL 130 (manufactured by Daicel Corporation) Isobornyl methacrylate: Product name Light Ester IB-X (Kyoeisha Chemical Co., Ltd.)

[0108] (F): Other (meth)acrylates (not belonging to (meth)acrylate (C) according to this embodiment) o-Phenylenphenol (EO) acrylate: Product name KOMERATE A011 (manufactured by Green Chemical Co., Ltd.) Biphenyl methyl acrylate: Trade name Miramer 1192 (manufactured by MIWON) 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] (Consideration) The results of the above examples show that the inclusion of a (meth)acrylate (C) structure that is less susceptible to photodegradation improves light resistance. Preferably, including 10% by mass or more of the total solid content enhances the light resistance effect, and it can be used in particular as a diffracting element or light guide plate for HMDs used outdoors, camera lenses, and smart glasses.

Claims

1. An active energy ray curable composition comprising inorganic fine particles (A), a dispersant (B), and a (meth)acrylate (C) having an aliphatic cyclic structure, The inorganic fine particles (A) are zirconia nanoparticles having an average primary particle diameter of 1 to 50 nm and a crystalline structure including a monoclinic system, and their content is 20 to 90% by mass relative to the total amount of the active energy ray curable composition. The dispersant (B) is represented by the following structural formula (4), and its content is 5 to 40 parts by mass per 100 parts by mass of the inorganic fine particles (A). The content of the (meth)acrylate (C) is 5 to 70% by mass relative to the total amount of the active energy ray curable composition. An active energy ray curable composition wherein the refractive index of the cured product is 1.60 to 1.

75. 【Chemistry 1】 (In the formula R １ R is a hydrogen atom or a methyl group, ２ (This is an alkylene chain with 2 to 4 carbon atoms. Also, x is an integer between 4 and 10, y is an integer greater than or equal to 1, and n is an integer between 1 and 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】 【Transformation 3】 【Chemistry 4】 (In general formulas (1), (2), and (3), R １ , R ２ , R ５ , R ７ is each independently a hydrogen atom or a methyl group. R ３ , R ４ is each independently a methylene group with a direct bond or an ethylene oxide chain having 4 or fewer repeating units. R ６ , R ８ is a direct-bonded oxygen atom or an ethylene oxide chain having 4 or fewer repeating units.)

3. The active energy ray curable composition according to claim 1 or 2, further comprising a photopolymerization initiator (D).

4. An optical article or optical sheet comprising a cured product pattern of the active energy ray curable composition described in claim 3.

5. The optical article or optical sheet according to claim 4, wherein the line width of the cured material pattern is 50 μm or less.

Images