Active energy ray-curable composition

Abstract

To provide an active energy ray-curable composition which has excellent glass adhesion properties and dispersion stability and provide a cured product having a high refractive index.SOLUTION: There is provided an active energy ray-curable composition which comprises an active energy ray-polymerizable compound (A), inorganic particles (B), a photopolymerization initiator (C), an organic solvent (D) and a dispersant (E), wherein the number average particle diameter of the inorganic particles (B) is 5 to 40 nm, the active energy ray-polymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the dispersant (E) is an anionic surfactant having a carboxyl group and the anionic surfactant having a carboxyl group contains a fatty acid having 12 to 36 carbon atoms.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an active energy ray-curable composition. [Background technology]

[0002] In recent years, high refractive index particles have been widely studied as fillers for anti-reflection materials, lens materials, high dielectric materials, etc. High refractive index particles of several to several tens of nanometers in size are particularly popular due to their excellent transparency. Conventionally, particles such as zirconia and titania have been used for UV-curable resins (Patent Document 1). However, with this technology, the dispersibility in solvents was insufficient, the haze was large, and the imprintability on glass was insufficient, making it necessary to use a primer when imprinting on a glass substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-6984 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an active energy ray-curable composition which gives a cured product having a high refractive index and which is excellent in glass adhesion and dispersion stability.

[0005] The present inventors have conducted extensive research to solve these problems and have arrived at the present invention. That is, the present invention provides an active energy ray-curable composition comprising an active energy ray-polymerizable compound (A), inorganic particles (B), a photopolymerization initiator (C), an organic solvent (D), and a dispersant (E), wherein the inorganic particles (B) have a number average particle diameter of 5 to 40 nm, the active energy ray-polymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the dispersant (E) is an anionic surfactant having a carboxyl group, and the anionic surfactant having a carboxyl group contains a fatty acid having 12 to 36 carbon atoms; and a cured product of the active energy ray-curable composition. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide an active energy ray-curable composition that gives a cured product having a high refractive index and is excellent in glass adhesion and dispersion stability. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present invention will be described in detail below.

[0008] <Active energy ray-curable composition> The active energy ray-curable composition of the present invention (hereinafter also referred to as "the curable composition of the present invention") is an active energy ray-curable composition comprising an active energy ray-polymerizable compound (A), inorganic particles (B), a photopolymerization initiator (C), an organic solvent (D), and a dispersant (E), wherein the inorganic particles (B) have a number average particle diameter of 5 to 40 nm, the active energy ray-polymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the dispersant (E) is an anionic surfactant having a carboxyl group, and the anionic surfactant having a carboxyl group contains a fatty acid having 12 to 36 carbon atoms.

[0009] <Active energy ray polymerizable compound (A)> The active energy ray-polymerizable compound (A) will be explained below. The active energy ray-polymerizable compound (A) is not particularly limited as long as it contains a monofunctional monomer (A1) and a polyfunctional monomer (A2) and has a functional group that polymerizes when exposed to active energy rays. Examples of active energy rays include visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, γ-rays, and electron beams. Note that ultraviolet light refers to light having a wavelength of 200 nm to 410 nm. Preferred examples of the functional group that polymerizes when exposed to active energy rays include functional groups having an ethylenically unsaturated bond, such as a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, a nadimide group, and a (meth)acryloyl group. From the viewpoint of curability, a vinyl group or a (meth)acryloyl group is more preferred. Furthermore, the monofunctional monomer (A1) is a compound having one functional group that undergoes a polymerization reaction when exposed to active energy rays, and the polyfunctional monomer (A2) is a compound having two or more functional groups that undergo a polymerization reaction when exposed to active energy rays. In this specification, "(meth)acrylate" means "acrylate and / or methacrylate," "(meth)acrylic" means "acrylic and / or methacrylic," and "(meth)acryloyl" means "acryloyl and / or methacryloyl."

[0010] Examples of the monofunctional monomer (A1) include monofunctional (meth)acrylates, monofunctional urethane (meth)acrylates, monofunctional (meth)acrylamides, and monofunctional N-vinyl compounds.

[0011] Examples of the monofunctional (meth)acrylate include mono(meth)acrylates having a chain aliphatic group having 4 to 22 carbon atoms {e.g., 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, 2-ethylhexyl(meth)acrylate, etc.}, glycidyl(meth)acrylate, hydroxyalkyl(meth)acrylate {e.g., 2-hydroxyethyl(meth)acrylate, acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc.}, alkoxyalkyl (meth)acrylate {for example, 2-methoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, etc.}, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 4-nonylphenoxyethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, alicyclic skeleton-containing mono(meth)acrylates [for example, (meth)acrylates containing an alicyclic skeleton having 6 to 12 carbon atoms {for example, cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, cyclohexylethyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 2-acryloyloxyethyl hexahydrophthalate, etc.}], aromatic ring skeletons (meth)acrylates [for example, aromatic ring skeleton-containing mono(meth)acrylates having 6 to 55 carbon atoms {for example, phenyl(meth)acrylate, benzyl(meth)acrylate, phenoxyethyl(meth)acrylate, phenoxy 2-methylethyl(meth)acrylate, phenoxyethoxyethyl(meth)acrylate (phenoxydiethylene glycol(meth)acrylate), paracumylphenoxyethyl(meth)acrylate, 4-biphenylmethylacrylate, phenoxybenzyl(meth)acrylate (m-phenoxybenzyl acrylate),2-hydroxy-3-phenoxypropyl (meth)acrylate, phenylbenzyl (meth)acrylate, phenylphenoxyethyl acrylate (o-phenoxyphenylethyl acrylate), (naphthyl)methyl acrylate, 1,1-biphenyl-2-yl acrylate, dinaphthothiophene derivatives, and mono(meth)acrylate compounds containing a fluorene skeleton}], and other mono(meth)acrylate compounds.

[0012] Examples of the monofunctional urethane (meth)acrylate include a reaction product of a monofunctional (meth)acrylate (a) having a hydroxyl group and an organic monoisocyanate compound (b). Examples of the monofunctional (meth)acrylate (a) having a hydroxyl group include hydroxyalkyl (meth)acrylates (2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 1,4-cyclohexanedimethanol monoacrylate). The monofunctional (meth)acrylate (a) having a hydroxyl group may be used alone or in combination of two or more kinds. Examples of the organic monoisocyanate compound (b) include an aliphatic monoisocyanate compound (b1), an alicyclic monoisocyanate compound (b2), and an aromatic monoisocyanate compound (b3). The aliphatic monoisocyanate compound (b1) includes those having an alkyl group having 1 to 20 carbon atoms, such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, hexyl isocyanate, octyl isocyanate, lauryl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate, and octadecyl isocyanate. The alicyclic monoisocyanate compound (b2) includes compounds having a hydrocarbon group with 5 to 13 carbon atoms and an alicyclic skeleton, such as cyclohexyl isocyanate. The aromatic monoisocyanate compound (b3) includes those having a hydrocarbon group with an aromatic ring and 6 to 12 carbon atoms, such as phenyl isocyanate and tolylene isocyanate. The organic monoisocyanate compound (b) may be used alone or in combination of two or more kinds.

[0013] Of these organic monoisocyanate compounds (b), from the viewpoint of flexibility and viscosity of the cured product, preferred are the aliphatic monoisocyanate compound (b1) and the alicyclic monoisocyanate compound (b2), more preferred are the aliphatic monoisocyanate compound (b1), next more preferred are aliphatic monoisocyanate compounds having an alkyl group having 1 to 6 carbon atoms, and particularly preferred are methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate and hexyl isocyanate.

[0014] The monofunctional urethane (meth)acrylate can be obtained by a known urethane reaction between a monofunctional (meth)acrylate (a) having a hydroxyl group and an organic monoisocyanate compound (b). Commercially available products may also be used, such as Viscoat #216 (2-[(butylamino)carbonyl]oxyethyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.), Etermer EM2080 (manufactured by Choko Materials Industry Co., Ltd.), and Genomer 1122 (manufactured by RAHN).

[0015] Examples of monofunctional (meth)acrylamides include (meth)acrylamide, N-alkoxy(meth)acrylamide, N-alkyl(meth)acrylamide, N-alkoxyalkyl(meth)acrylamide, N-hydroxyalkyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide, N-alkoxy-N-alkyl(meth)acrylamide, and cyclic amides having an N-(meth)acryloyl group (heterocyclic skeleton-containing N-(meth)acrylamide). N-alkoxy(meth)acrylamides include those having an alkoxy group having 1 to 6 carbon atoms, such as N-methoxy(meth)acrylamide, N-ethoxy(meth)acrylamide, N-propoxy(meth)acrylamide, and N-butoxy(meth)acrylamide. N-Alkyl(meth)acrylamides include those having an alkyl group having 1 to 6 carbon atoms, such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-butyl(meth)acrylamide. N-alkoxyalkyl(meth)acrylamides include those having an alkoxyalkyl group having 1 to 6 carbon atoms, such as Nn-butoxymethylacrylamide. N-hydroxyalkyl(meth)acrylamides include those having a hydroxyalkyl group having 1 to 6 carbon atoms, such as N-hydroxyethyl(meth)acrylamide. N,N-dialkyl(meth)acrylamides include those having an alkyl group having 1 to 22 carbon atoms, and examples thereof include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N,N-diisobutyl(meth)acrylamide, N,N-di-tert-butyl(meth)acrylamide, N,N-diheptyl(meth)acrylamide, N,N-dioctyl(meth)acrylamide, N,N-di-tert-octyl(meth)acrylamide, N,N-didodecyl(meth)acrylamide, and N,N-dioctadecyl(meth)acrylamide. Examples of N-alkoxy-N-alkyl(meth)acrylamides include Nn-butoxy-N-methyl(meth)acrylamide, N-methyl-N-methoxy(meth)acrylamide, N-methyl-N-ethoxy(meth)acrylamide, N-methyl-N-propoxy(meth)acrylamide, N-ethyl-N-methoxy(meth)acrylamide, N-ethyl-N-ethoxy(meth)acrylamide, N-ethyl-N-butoxy(meth)acrylamide, N-propyl-N-methoxy(meth)acrylamide, N-propyl-N-ethoxy(meth)acrylamide, N-butyl-N-methoxy(meth)acrylamide, and N-butyl-N-ethoxy(meth)acrylamide. Examples of cyclic amides having an N-(meth)acryloyl group (also referred to as heterocyclic skeleton-containing mono N-(meth)acrylamides) include N-(meth)acryloylmorpholine, N-(meth)acryloylthiomorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, and N-(meth)acryloylpiperidine.

[0016] Examples of monofunctional N-vinyl compounds include N-vinylcaprolactam, N-vinylformamide, N-vinylimidazole, N-vinylacetamide, and N-vinyl compounds containing a heterocyclic skeleton (e.g., N-vinyl-2-pyrrolidone, 5-methyl-3-vinyl-2-oxazolidinone, N-vinylcarbazole, and N-vinylphthalimide).

[0017] Of the monofunctional monomers (A1), from the viewpoints of curability, refractive index, and cure shrinkage, monofunctional (meth)acrylates and monofunctional (meth)acrylamides are preferred, and at least one monomer selected from the group consisting of alicyclic skeleton-containing mono(meth)acrylates, aromatic ring skeleton-containing mono(meth)acrylates, and heterocyclic skeleton-containing mono-N-(meth)acrylamides is more preferred. Specifically, the alicyclic skeleton-containing mono(meth)acrylate is preferably isobornyl acrylate, and the aromatic ring skeleton-containing mono(meth)acrylate is preferably phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, o-phenoxyphenylethyl acrylate, m-phenoxybenzyl acrylate, (naphthyl)methyl acrylate, benzyl acrylate, 4-biphenylmethyl acrylate, and dinaphthothiophene derivatives, and the heterocyclic skeleton-containing mono(meth)acrylamides is preferably N-(meth)acryloylmorpholine, etc. Particularly preferred are aromatic ring skeleton-containing mono(meth)acrylates, and specifically preferred are phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, o-phenoxyphenylethyl acrylate, m-phenoxybenzyl acrylate, (naphthyl)methyl acrylate, and benzyl acrylate.

[0018] Examples of the polyfunctional monomer (A2) include polyfunctional (meth)acrylate compounds and polyfunctional urethane (meth)acrylate compounds.

[0019] Examples of polyfunctional (meth)acrylate compounds include difunctional (meth)acrylates, trifunctional (meth)acrylates, tetrafunctional (meth)acrylates, pentafunctional (meth)acrylates, and hexafunctional or higher (meth)acrylates. Examples of the bifunctional (meth)acrylate include di(meth)acrylates having an aromatic ring skeleton {for example, di(meth)acrylates of alkylene oxide (hereinafter, alkylene oxide may be abbreviated as "AO") adducts of dihydric phenol compounds [monocyclic phenols (catechol, resorcinol, hydroquinone, etc.), condensed polycyclic phenols (dihydroxynaphthalene, etc.), bisphenol compounds (bisphenol A, bisphenol F, bisphenol S, etc.)] (for example, ethoxylated bisphenol A diacrylate, propoxylated bisphenol A diacrylate, etc.), acrylic-modified bisphenoxyethanol fluorene, binaphthol derivatives, naphthothiol derivatives, etc.}, monomers having a fluorene skeleton (fluorene acrylate derivatives), monomers having a biphenyl skeleton (4-biphenylmethyl acrylate, 1,1-biphenyl-2-yl acrylate, 4,4' ... Examples of suitable monomers include bis(4-methacryloylthiophenyl)sulfide and diphenyl sulfide skeleton-containing monomers {bis(4-methacryloylthiophenyl)sulfide, 1,1'-thiobis(4-ethenylthiobenzene)}, polyalkylene glycol di(meth)acrylates (dipropylene glycol diacrylate, neopentyl glycol diacrylate, etc.), alicyclic skeleton-containing di(meth)acrylates {for example, dimethylol-tricyclodecane di(meth)acrylate, bis(vinyl sulfone)tricyclo[5.2.1.0]decane, etc.}, heterocyclic skeleton-containing monomers (dinaphthothiophene derivatives (for example, dinaphthothiophene diacrylate), isocyanuric acid derivatives (for example, isocyanuric acid EO-modified diacrylate), etc.), neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate. Specific examples of the di(meth)acrylate of an AO adduct of a dihydric phenol compound include a di(meth)acrylate of an adduct of 4 moles of ethylene oxide (hereinafter, ethylene oxide may be abbreviated as "EO") to resorcinol, a di(meth)acrylate of an adduct of 4 moles of propylene oxide (hereinafter, propylene oxide may be abbreviated as "PO") to dihydroxynaphthalene, a di(meth)acrylate of an adduct of bisphenol A with 4 moles of EO, a di(meth)acrylate of an adduct of bisphenol A with 10 moles of EO, and a di(meth)acrylate of an adduct of bisphenol A with 20 moles of EO.

[0020] Examples of trifunctional (meth)acrylates include trimethylolpropane tri(meth)acrylate, tri(meth)acrylates of AO adducts of trimethylolpropane (e.g., 6-mol EO adduct, 9-mol EO adduct, 15-mol EO adduct, 20-mol EO adduct, and 9-mol PO adduct of trimethylolpropane), pentaerythritol tri(meth)acrylate, tri(meth)acrylates of AO adducts of pentaerythritol (e.g., 6-mol EO adduct of pentaerythritol), and tri(meth)acrylates of AO adducts of glycerin (e.g., 6-mol EO adduct and 3-mol PO adduct of glycerin).

[0021] Examples of tetrafunctional (meth)acrylates include pentaerythritol tetra(meth)acrylate, tetra(meth)acrylates of AO adducts of pentaerythritol (e.g., 2-mol EO adduct, 4-mol EO adduct, 10-mol EO adduct, 15-mol EO adduct and 35-mol EO adduct of pentaerythritol), and tetra(meth)acrylates of AO adducts of ditrimethylolpropane (e.g., 10-mol EO adduct of ditrimethylolpropane).

[0022] Examples of the pentafunctional (meth)acrylate include dipentaerythritol penta(meth)acrylate and penta(meth)acrylates of AO adducts of dipentaerythritol (dipentaerythritol adducts of 2 moles of EO, 4 moles of EO, 10 moles of EO, and 15 moles of EO, etc.).

[0023] Examples of the hexa- or higher functional (meth)acrylate include dipentaerythritol hexa(meth)acrylate, hexa(meth)acrylate of an AO adduct of dipentaerythritol (e.g., an EO 2-mol adduct, an EO 4-mol adduct, an EO 10-mol adduct, and an EO 15-mol adduct of dipentaerythritol), and hexa(meth)acrylate of a lactone (e.g., γ-butyrolactone, γ-valerolactone, and ε-caprolactone) adduct of dipentaerythritol (e.g., an ε-caprolactone 3-mol adduct, an ε-caprolactone 6-mol adduct, and an ε-caprolactone 12-mol adduct of dipentaerythritol).

[0024] Examples of polyfunctional urethane (meth)acrylate compounds include difunctional urethane (meth)acrylates, trifunctional urethane (meth)acrylates, tetrafunctional urethane (meth)acrylates, pentafunctional urethane (meth)acrylates, and hexafunctional or higher urethane (meth)acrylates. The polyfunctional urethane (meth)acrylate may be commercially available, such as Ebecryl 230, Ebecryl 8807, Ebecryl 9270, Ebecryl 8800, Ebecryl 4513, Ebecryl 680, Ebecryl 5129, KRM 8296, and KRM 8904 (all manufactured by Daicel-Allnex Co., Ltd.).

[0025] Of the polyfunctional monomers (A2), polyfunctional (meth)acrylate compounds are preferred from the viewpoints of curability, refractive index, and cure shrinkage, and di- to hexafunctional (meth)acrylates are more preferred. Of the bifunctional (meth)acrylates, at least one monomer selected from the group consisting of alicyclic skeleton-containing di(meth)acrylates, aromatic ring skeleton-containing di(meth)acrylates, and heterocyclic skeleton-containing di(meth)acrylates is even more preferred, and alicyclic skeleton-containing di(meth)acrylates and aromatic ring skeleton-containing di(meth)acrylates are particularly preferred. Specifically, the alicyclic skeleton-containing di(meth)acrylate is preferably dimethylol-tricyclodecane diacrylate or dimethylol-tricyclodecane dimethacrylate, the aromatic ring skeleton-containing di(meth)acrylate is preferably ethoxylated bisphenol A diacrylate, propoxylated bisphenol A diacrylate, acrylic-modified bisphenoxyethanol fluorene, 4,4'-bisacryloxymethyl biphenyl, or the like, and the tri- to hexafunctional (meth)acrylate is preferably trimethylolpropane tri(meth)acrylate or trimethylolpropane dimethacrylate. Preferred are tri(meth)acrylates of AO adducts of pentaerythritol [adducts of trimethylolpropane with 6 moles of EO and adducts of 9 moles of EO], pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, tetra(meth)acrylates of AO adducts of pentaerythritol [adducts of pentaerythritol with 2 moles of EO and adducts of 4 moles of EO], dipentaerythritol hexa(meth)acrylate, and hexa(meth)acrylates of AO adducts of dipentaerythritol [adducts of dipentaerythritol with 2 moles of EO and adducts of 4 moles of EO].

[0026] The weight ratio of the monofunctional monomer (A1) to the polyfunctional monomer (A2) [(A1) / (A2)] is preferably 0.1 to 9, more preferably 0.2 to 9, from the viewpoint of adhesion.

[0027] From the viewpoint of the refractive index of the cured product, the monomer constituting the active energy ray-polymerizable compound (A) preferably contains a monomer having at least one aromatic ring, more preferably a monomer having two or more aromatic rings, and further preferably contains a monomer having an alicyclic skeleton in order to reduce cure shrinkage.

[0028] From the viewpoints of the refractive index of the cured product and reducing cure shrinkage, the active energy ray-polymerizable compound (A) preferably has a total content of alicyclic skeleton-containing mono(meth)acrylate, aromatic ring skeleton-containing mono(meth)acrylate, heterocyclic skeleton-containing mono-N-(meth)acrylamide, aromatic ring skeleton-containing di(meth)acrylate, heterocyclic skeleton-containing di(meth)acrylate, and alicyclic skeleton-containing di(meth)acrylate of 1 to 99 wt %, more preferably 20 to 99 wt %, based on the weight of the active energy ray-polymerizable compound (A).

[0029] The refractive index of the cured product of the active energy ray-polymerizable compound (A) is preferably 1.50 or more, more preferably 1.53 or more, from the viewpoint of thinning. The refractive index can be controlled by adjusting the amount of molecules containing atoms with different atomic refractions. The refractive index of the cured product of the active energy ray-polymerizable compound (A) can be measured by the following method. The active energy ray-polymerizable compound (A) mixed and dissolved with a photopolymerization initiator was sandwiched between two PET films [trade name: Lumirror S, manufactured by Toray Industries, Inc.] so that the active energy ray-polymerizable compound (A) had a thickness of about 5 μm, and was then irradiated with 1000 mJ / cm using an ultraviolet ray irradiation device [trade name: VPS / I600, manufactured by Fusion UV Systems, Inc.]. 2 After obtaining a cured product for refractive index evaluation by irradiating it with ultraviolet light, the refractive index at a wavelength of 589 nm (D line) is measured using an Abbe refractometer (DR-M2: manufactured by Atago Co., Ltd.). The refractive index of the active energy ray-polymerizable compound (A) is the refractive index of a cured product prepared without mixing with the inorganic particles (B), the photopolymerization initiator (C), and other components, and is measured based only on the composition of the active energy ray-polymerizable compound (A) constituting the active energy ray-curable composition.

[0030] <Inorganic particles (B)> The inorganic particles (B) will be explained below. The inorganic particles (B) are not particularly limited as long as they are inorganic particles with a number average particle size of 5 to 40 nm. Preferred inorganic particles include, for example, compounds of metal elements and compounds of nonmetal elements, and examples of the compounds include hydrogen compounds, oxides, oxoacids, hydroxides, halides, sulfates, nitrates, carbonates, acetates, and metal complexes. Among the above inorganic compounds, from the viewpoint of refractive index, metal oxides, nonmetal oxides, and oxides containing metal and nonmetal elements are preferred. The inorganic particles (B) may be used alone or in combination of two or more kinds.

[0031] As the oxide particles for the inorganic particles (B), from the viewpoint of refractive index, at least one type of particles selected from the group consisting of TiO2, SiO2, BaTiO3, ZnO, MgO, SnO2, Al2O3, ZrO2, CeO2, Fe2O3, Fe3O4, WO3, Y2O3, SrTiO3, FeTiO3, MnTiO3, Nb2O5, and KTaO3 is preferred.

[0032] The number-average particle diameter of the inorganic particles (B) is 5 to 40 nm, because it provides excellent dispersion stability and a cured product with high light transmittance and refractive index. In the present invention, the number-average particle diameter of the inorganic particles (B) is the average primary particle diameter measured from approximately 300 particles in a photograph (25k) observed with a transmission electron microscope (JEM-F200 manufactured by JEOL Ltd.). Here, the average primary particle diameter is the particle diameter obtained by averaging the diameter of a circle (circle-equivalent diameter) having the same area as the area determined for each particle from the photograph for all measured particles.

[0033] The shape of the inorganic particles (B) is not particularly limited, and may be, for example, spherical, hollow, porous, rod-like, plate-like, fibrous, or amorphous. Among these, spherical shapes are preferred because they provide excellent dispersion stability and allow the production of cured products with high light transmittance and refractive index. The crystalline structure of the inorganic particles (B) is not particularly limited, but a monoclinic system is preferred because it provides excellent dispersion stability and a cured product with high light transmittance and refractive index.

[0034] <Photopolymerization initiator (C)> The photopolymerization initiator (C) will be explained below. The photopolymerization initiator (C) may be any of a photoradical polymerization initiator, a photoanionic polymerization initiator, and a photocationic polymerization initiator. Examples of the photopolymerization initiator (C) include benzoin compounds (C1), alkylphenone compounds (C2), anthraquinone compounds (C3), thioxanthone compounds (C4), ketal compounds (C5), benzophenone compounds (C6), phosphine oxides (C7), and oxime ester compounds (C8).

[0035] Examples of the benzoin compound (C1) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether. Examples of the alkylphenone compound (C2) include acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone. Examples of the anthraquinone compound (C3) include 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone. Examples of the thioxanthone compound (C4) include 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone. Examples of the ketal compound (C5) include acetophenone dimethyl ketal and benzyl dimethyl ketal. Examples of the benzophenone compound (C6) include benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bismethylaminobenzophenone. Examples of the phosphine oxide (C7) include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylethylphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Examples of the oxime ester compound (C8) include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime).

[0036] Of these photopolymerization initiators (C), 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylethylphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide are preferred from the viewpoint of curability. The photopolymerization initiator (C) may be used alone or in combination of two or more kinds.

[0037] <Organic solvent (D)> The organic solvent (D) will be explained below. Examples of the organic solvent (D) include alcohols (methanol, ethanol, isopropanol, butanol, 3-methoxybutanol, octanol, and the like); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like); esters (ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, methoxybutyl acetate (3-methoxybutyl acetate), propylene glycol monomethyl ether acetate (2-methoxy-1-methylethyl acetate), propylene glycol monoethyl ether acetate, and the like); ethers (ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, and the like); aromatic hydrocarbons (benzene, toluene, xylene, and the like); and amides (dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and the like). Of these, from the viewpoint of compatibility with the active energy ray-curable composition of the present invention, methanol, isopropanol, butanol, methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone, ethyl acetate, 2-methoxy-1-methylethyl acetate, methoxybutyl acetate (3-methoxybutyl acetate), toluene, and xylene are preferred. The organic solvent (D) may be used alone or in combination of two or more kinds.

[0038] <Dispersant (E)> The dispersant (E) will be explained below. The dispersant (E) is adsorbed onto the surface of the inorganic particles and serves to uniformly disperse the inorganic particles in the cured product. It is an anionic surfactant having a carboxyl group, and there are no particular restrictions on the anionic surfactant having a carboxyl group as long as it contains a fatty acid having 12 to 36 carbon atoms. The dispersant (E) may be used alone or in combination of two or more kinds.

[0039] Examples of fatty acids having 12 to 36 carbon atoms include lauric acid, myristic acid, palmitic acid, margaric acid, oleic acid, stearic acid, and isostearic acid.

[0040] Of the fatty acids having 12 to 36 carbon atoms, fatty acids having 12 to 18 carbon atoms are preferred, and lauric acid and isostearic acid are more preferred, from the viewpoint of dispersion stability and adhesion.

[0041] The dispersant (E) may contain, in addition to the essential component fatty acid having 12 to 36 carbon atoms, an anionic surfactant having a carboxyl group other than those mentioned above. Examples of anionic surfactants having a carboxyl group other than those mentioned above include compounds having a (meth)acryloyloxy group or a vinyl group and a carboxyl group (such as carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone mono(meth)acrylate, monohydroxyethyl phthalate (meth)acrylate, 2-acryloyloxyethyl succinate, 2-methacryloyloxyethyl succinate, 2-acryloyloxyethyl hexahydrophthalate, and 2-methacryloyloxyethyl hexahydrophthalate), and salts thereof.

[0042] The content of the fatty acid having 12 to 36 carbon atoms in the dispersant (E) is preferably 15% by weight to 100% by weight based on the weight of the dispersant (E).

[0043] The HLB of the fatty acid having 12 to 36 carbon atoms is preferably 5 to 11, and more preferably 5 to 9, from the viewpoint of dispersion stability. The HLB of the fatty acid having 12 to 36 carbon atoms can be adjusted by adjusting the ratio of the hydrophilic skeleton and the lipophilic skeleton introduced. The HLB value is a measure of the balance between hydrophilicity and lipophilicity, and the higher the HLB value, the higher the inorganicity. This is known as the value calculated by the Oda method described in, for example, "Introduction to Surfactants," 2007, Sanyo Chemical Industries, Ltd., by Takehiko Fujimoto, p. 212, and is not the value calculated by the Griffin method. The HLB value can be calculated from the ratio of the organicity value to the inorganicity value of an organic compound. HLB=10×Inorganic / Organic Here, the inorganic and organic values ​​in the above formula represent index values ​​that express organic and inorganic properties proposed by Fujita et al., and can be calculated using the values ​​in the table on page 213 of the aforementioned "Introduction to Surfactants."

[0044] The active energy ray-curable composition of the present invention may contain other additives as needed within the range that does not impair the effects of the present invention. Examples of additives include a release agent, an antioxidant, a hindered amine light stabilizer, an ultraviolet absorber, an antistatic agent, a colorant, a polymerization inhibitor, a chain transfer agent, a filler, a surfactant, a plasticizer, a dispersant, and a thixotropy-imparting agent (thickener).

[0045] Examples of the release agent (F) include fluorine additives, acrylic leveling agents, and silicone leveling agents. Examples of fluorine additives include BM-1000 and BM-1100 (all manufactured by BM CHEMIE), Megafac F-142D, F-172, F-173, F-183, F-178, F-471, F-477, F-444, F-552, and F-554 (all manufactured by DIC Corporation), and Surflon S-242, S-420, S-431, S-386, S-611, S-651, S-656, S-658, and S-693 (all manufactured by AGC Seimi Chemical Co., Ltd.). Examples of acrylic leveling agents include Disparlon UVX-36 (manufactured by Kusumoto Chemicals Co., Ltd.). Examples of silicone leveling agents include KP-423 (manufactured by Shin-Etsu Chemical Co., Ltd.) and Polyflow KL-401 (manufactured by Kyoeisha Co., Ltd.). The release agent (F) may be used alone or in combination of two or more kinds.

[0046] The weight proportion of the active energy ray-polymerizable compound (A) in the present invention is preferably 3% by weight to 50% by weight, more preferably 3% by weight to 30% by weight, based on the total weight of the active energy ray-polymerizable compound (A), inorganic particles (B), photopolymerization initiator (C), and dispersant (E). When the weight proportion of (A) is 3% by weight or more, the adhesiveness is good, and when it is 50% by weight or less, the refractive index of the cured product is good.

[0047] The weight proportion of the inorganic particles (B) in the present invention is preferably 48.9% by weight to 95.9% by weight, more preferably 68% by weight to 95% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the inorganic particles (B), the photopolymerization initiator (C), and the dispersant (E). When the weight proportion of (B) is 48.9% by weight or more, the refractive index of the cured product is good, and when it is 95.9% by weight or less, the adhesiveness is good.

[0048] The weight proportion of the photopolymerization initiator (C) in the present invention is preferably 0.1 to 10% by weight, more preferably 1 to 5% by weight, and particularly preferably 1 to 3% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the inorganic particles (B), the photopolymerization initiator (C), and the dispersant (E).

[0049] The weight proportion of the organic solvent (D) in the present invention is preferably 0.001% by weight to 800% by weight, more preferably 0.5% by weight to 700% by weight, and particularly preferably 1% by weight to 500% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the inorganic particles (B), the photopolymerization initiator (C), and the dispersant (E).

[0050] The weight proportion of the dispersant (E) in the present invention is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the inorganic particles (B), the photopolymerization initiator (C), and the dispersant (E). When the weight proportion of (E) is 1% by weight or more, the dispersion stability is good, and when it is 20% by weight or less, the refractive index of the cured product is good.

[0051] The weight proportion of the other additives in the present invention is preferably 0.01% by weight to 10% by weight based on the total weight of the active energy ray-polymerizable compound (A), inorganic particles (B), photopolymerization initiator (C), and dispersant (E).

[0052] The active energy ray-curable composition of the present invention can be produced, for example, by uniformly mixing the active energy ray-polymerizable compound (A), inorganic particles (B), photopolymerization initiator (C), organic solvent (D), dispersant (E), and other additives using a known mechanical mixing method (a method using a mechanical stirrer, a magnetic stirrer, or the like). The inorganic particles (B) may be dispersed in an organic solvent (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and propylene glycol monomethyl ether acetate). In order to adjust the weight ratio of the organic solvent to a desired amount, the organic solvent may be distilled off under reduced pressure.

[0053] <Cured product> The cured product of the present invention is obtained by distilling off the organic solvent (D) from the active energy ray-curable composition of the present invention and curing the composition, and can be obtained, for example, by irradiating a coating film obtained by molding the active energy ray-curable composition of the present invention with active energy rays to cure the coating film. Examples of active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays, electron beams, etc. Ultraviolet rays refer to light rays with a wavelength of 200 nm to 410 nm. The wavelength of the active energy ray is not particularly limited as long as it can cure the composition, but is preferably 350 nm to 410 nm. A typical example of the active energy ray is light with a wavelength of 365 nm. The irradiation intensity of the active energy rays is not particularly limited as long as it can cure the composition, but is preferably 20 mW / cm 2 ~20,000mW / cm 2 It is preferable that: The cumulative exposure dose of active energy rays is 100 mJ / cm 2 ~30,000mJ / cm 2 The irradiation time may be determined depending on the irradiation intensity.

[0054] When using ultraviolet light as the active energy ray, the light source can be a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a high-power metal halide lamp, etc. (Latest Trends in UV / EB Curing Technology, edited by RadTech Research Group, CMC Publishing, p. 138, 2006), or an LED. Compared to other light sources, LEDs consume less power and generate less ozone, resulting in lower running costs and a lower environmental impact. When curing with an LED light source, an LED light source ultraviolet irradiation device [e.g., LED light source ultraviolet irradiation device "FJ100" 150 x 20 365, manufactured by Phoseon Technology Co., Ltd.] can be used.

[0055] The shape of the portion irradiated with active energy rays may be an area type having a certain area or a line type. In the case of a line type, the entire coating film can be irradiated with light by moving the coating film relative to the light source or by moving the light source relative to the coating film. In the case of a line type, the irradiation time can be easily adjusted, and therefore the cumulative exposure amount can be easily adjusted.

[0056] Irradiation with active energy rays may be carried out in the atmosphere. Because the composition of the present invention has good reactivity, the reaction of the composition can be allowed to proceed and cured even in the atmosphere. It is particularly preferable to irradiate the composition with active energy rays in a dry atmosphere to cure it. In this case, moisture absorption by the cured composition can be suppressed.

[0057] In the present invention, the cured product may be further heated. Heating further promotes curing, thereby lowering the linear expansion coefficient of the cured product. When further heating is performed, the heating temperature is preferably 90°C or higher.

[0058] The active energy ray-curable composition of the present invention can be cured to produce a molded article that can be suitably used as an optical component (optical lens, sheet for optical lens, film, coating material for decorative film, coating material for optical fiber, hard coat film, antireflection film, etc.).

[0059] A method for producing a molded article by curing the active energy ray-curable composition of the present invention will be described below. The method for producing the optical component using the active energy ray-curable composition of the present invention is not particularly limited, and for example, coating and molding can be performed by the following method: That is, the composition of the present invention is coated onto a transparent substrate (including a transparent film) using a bar coater or the like so that the thickness after curing is 50 nm to 150 μm, a mold is pressed onto the coated film, and the coated film is cured by irradiating the transparent substrate with active energy rays described below, and then the optical component is released from the mold.

[0060] Examples of the transparent substrate (including transparent film) include those made of glass, methyl methacrylate (co)polymer, polyethylene terephthalate, polycarbonate, polytriacetyl cellulose, polycycloolefin, and other resins. [Example]

[0061] The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" below refer to parts by weight.

[0062] <Preparation of active energy ray-curable composition> (Examples 1 to 6 and Comparative Examples 1 to 3) According to the blending parts (parts by weight) in Table 1, the active energy ray-polymerizable compound (A), inorganic particles (B), photopolymerization initiator (C), organic solvent (D), dispersant (E) and release agent (F) were charged into a glass container and stirred until homogeneous, thereby obtaining the active energy ray-curable compositions of Examples 1 to 6 and Comparative Examples 1 to 3.

[0063] [Table 1]

[0064] The raw materials used in Table 1 are as follows:

[0065] (A-1): Phenoxydiethylene glycol acrylate [P2H-A: manufactured by Kyoeisha Chemical Co., Ltd., refractive index (25°C): 1.51] (A-2): o-phenoxyphenylethyl acrylate [A-LEN-10: manufactured by Shin-Nakamura Chemical Co., Ltd., refractive index (25°C): 1.58] (A-3): m-phenoxybenzyl acrylate [POB-A: manufactured by Kyoeisha Chemical Co., Ltd., refractive index (25°C): 1.57] (A-4): (naphthyl)methyl acrylate [NMT-A: manufactured by Kyoeisha Chemical Co., Ltd., refractive index (25°C): 1.60] (A-5): Neopentyl glycol diacrylate [NP-A: Kyoeisha Chemical Co., Ltd., refractive index (25°C): 1.45] (A-6): Dimethylol-tricyclodecane diacrylate [Light Acrylate DCP-A: manufactured by Kyoeisha Co., Ltd., refractive index (25°C): 1.50] (A-7): Dimethylol-tricyclodecane dimethacrylate [DCP: manufactured by Shin-Nakamura Chemical Co., Ltd., refractive index (25°C): 1.50] (A-8): fluorene-based acrylate [EA-200: manufactured by Osaka Gas Chemicals Co., Ltd., refractive index (25°C): 1.61] (A-9): 1,1'-thiobis(4-ethenylthiobenzene) [Fujifilm Wako Pure Chemical Industries, Ltd., refractive index (25°C): 1.69] (A-10): Ethoxylated bisphenol A diacrylate [Neomer BA-641: manufactured by Sanyo Chemical Industries, Ltd., refractive index (25°C): 1.54] (A-11): Pentaerythritol tetraacrylate [Neomer EA-300: manufactured by Sanyo Chemical Industries, Ltd., refractive index (25°C): 1.48] (A-12): Dipentaerythritol hexaacrylate [Neomer DA-600: manufactured by Sanyo Chemical Industries, Ltd., refractive index (25°C): 1.47]

[0066] (B-1): A solution of zirconium oxide (ZrO2) particles dispersed in methyl ethyl ketone [product name "Zircostar AX-ZP-158-A, solid content: 70 wt%, number average particle diameter of zirconia particles: 17 nm", manufactured by Nippon Shokubai Co., Ltd.] (B-2): Titanium oxide (TiO2) particles [trade name "TTO-51(C)", titanium oxide particles with a number average particle diameter of 10-30 nm, manufactured by Ishihara Sangyo Kaisha, Ltd.] (B-3): A solution of barium titanate (BaTiO3) particles dispersed in propylene glycol monomethyl ether [product name "9714BT, solid content: 15 wt%, number average particle diameter of barium titanate particles: approximately 40 nm", manufactured by Tokushiki Co., Ltd.]

[0067] (C-1): 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name "IRGACURE TPO", manufactured by BASF) (C-2): 2,4,6-trimethylbenzoylethylphenylphosphine oxide (trade name "Omnirad TPO-L", manufactured by IGM Resins BV) (C-3): 1-hydroxycyclohexyl phenyl ketone [trade name "Irgacure 184", manufactured by BASF]

[0068] (D-1): 2-Methoxy-1-methylethyl acetate [PGMEA: Fujifilm Wako Pure Chemical Industries, Ltd.] (D-2): Methyl ethyl ketone [MEK: Fujifilm Wako Pure Chemical Industries, Ltd.] (D-3): Cyclohexanone [Fujifilm Wako Pure Chemical Industries, Ltd.] (D-4): 3-Methoxybutyl acetate [MBA: Fujifilm Wako Pure Chemical Industries, Ltd.]

[0069] (E-1): Isostearic acid [Nissan Chemical Co., Ltd., HLB: 5.2] (E-2): Lauric acid [Fujifilm Wako Pure Chemical Industries, Ltd., HLB: 6.3] (E-3): 2-acryloyloxyethyl hexahydrophthalic acid [HOA-HH: Kyoeisha Chemical Co., Ltd., HLB: 11.4] (E-4): 2-Acryloyloxyethyl succinic acid [HOA-MS: Kyoeisha Chemical Co., Ltd., HLB: 15.2]

[0070] (F-1): Fluorine additive [F-444: manufactured by DIC Corporation]

[0071] The refractive index, adhesion, and dispersion stability of the active energy ray-curable compositions prepared in each of the Examples and Comparative Examples were evaluated by the following methods.

[0072] <Method for preparing a cured product for refractive index evaluation> 1 g of the active energy ray-curable composition was dropped onto a 10 cm square glass substrate [Eagle XG, manufactured by Corning Incorporated] and applied by spin coating at 3000 rpm for 30 seconds, then dried at 100°C for 3 minutes, and then irradiated with ultraviolet light at 10000 mJ / cm using an ultraviolet irradiation device [VPS / I600, manufactured by Fusion UV Systems Co., Ltd.] under a nitrogen atmosphere. 2 The coating was irradiated and cured to obtain a cured product with a film thickness of 100 nm for refractive index evaluation.

[0073] <Refractive index> The refractive index of the cured product prepared as described above at 589 nm was measured using a reflection spectrophotometer [FE-3000, manufactured by Otsuka Electronics Co., Ltd.]. In this case, a refractive index of 1.60 or higher is considered to be satisfactory.

[0074] <Method for preparing cured products for adhesion evaluation> 1 g of KBM-5013 (Shin-Etsu Chemical Co., Ltd.) diluted to 1 wt % with methanol was dropped onto a 10 cm square glass substrate (Eagle XG, Corning Incorporated), and the substrate was spin-coated at 3000 rpm for 30 seconds and dried at 100° C. for 10 minutes. Next, 1 g of an active energy ray-curable composition was dropped onto the substrate, and the substrate was spin-coated at 3000 rpm for 30 seconds and dried at 100° C. for 3 minutes. After that, the substrate was exposed to 10,000 mJ / cm of ultraviolet light using a UV irradiation device (VPS / I600, Fusion UV Systems Co., Ltd.) under a nitrogen atmosphere. 2 The coating was irradiated and cured to obtain a cured product with a film thickness of 100 nm for evaluation of adhesion.

[0075] <Adhesion> For the cured product prepared as described above for adhesion evaluation, cellophane adhesive tape was attached to the surface of the cured product and peeled off at a 90-degree angle. The state of peeling of the cured product from the glass was visually observed and evaluated according to the following criteria. ◎: More than 90% of the cured material remains on the glass substrate 〇: 50% to less than 90% of the cured material remains on the glass substrate ×: Less than 50% of the cured material remains on the glass substrate

[0076] <Imprintability> (1) The active energy ray-curable composition was dropped onto a glass substrate [Eagle XG, manufactured by Corning] and applied by spin coating at 500 rpm for 30 seconds, and then dried at 100°C for 3 minutes. (2) The resin obtained in (1) was attached to a mold (DTM-3-1 manufactured by Kyodo International Co., Ltd.), and a roller was rolled over it to remove any air. UV light was applied from the glass side using a UV irradiation device [model number "VPS / I600" manufactured by Fusion UV Systems Co., Ltd.] at 1000 mJ / cm. 2 It was irradiated and cured. (3) The mold in (2) was removed, and the surface of the cured product was observed with an SEM and evaluated according to the following criteria. ◎: 80% or more of the irregularities are transferred. ◯: 30% to less than 80% of the irregularities are transferred. ×: Less than 30% of the irregularities were transferred.

[0077] <Dispersion stability> The active energy ray-curable composition was stored at 25°C for one month or three months. Whether the particle dispersion state was maintained after storage was evaluated. If there was no visible change and the particles did not settle after one month but settled or gelled after three months, the result was marked "Good." If the particles did not settle after three months, the result was marked "Excellent." If the coated particles settled after one month or if a clear increase in viscosity and gelling occurred, the result was marked "Poor."

[0078] As can be seen from the results in Table 1, Comparative Example 1, which did not contain dispersant (E), exhibited poor dispersion stability. Furthermore, Comparative Examples 2 and 3, which used active-energy-ray-curable compositions that did not contain a monofunctional monomer (A1) and a polyfunctional monomer (A2) in combination as the active-energy-ray-polymerizable compound (A), exhibited poor adhesion. In contrast, each of the Examples provided cured products that exhibited good results in all categories. [Industrial Applicability]

[0079] The cured product of the active energy ray-curable composition of the present invention has a high refractive index and is therefore useful as an optical member, specifically as an optical component such as a plastic lens (e.g., a prism lens, a lenticular lens, a microlens, a Fresnel lens, or a viewing angle improving lens), an optical compensation film, a retardation film, a prism, an optical fiber, a solder resist for flexible printed wiring, a plating resist, an interlayer insulating film for multilayer printed wiring boards, or a photosensitive optical waveguide.

Claims

1. An active energy ray-curable composition comprising an active energy ray-polymerizable compound (A), inorganic particles (B), a photopolymerization initiator (C), an organic solvent (D), and a dispersant (E), wherein the inorganic particles (B) have a number average particle diameter of 5 to 40 nm, the active energy ray-polymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the dispersant (E) is an anionic surfactant having a carboxyl group, and the anionic surfactant having a carboxyl group contains a fatty acid having 12 to 36 carbon atoms.

2. The inorganic particles (B) are TiO ２ , SiO ２ , BaTiO ３ , ZnO, MgO, SnO ２ , Al ２ O ３ , ZrO ２ , CeO ２ , Fe ２ O ３ , Fe ３ O ４ , W.O. ３ , Y ２ O ３ , SrTiO ３ , FeTiO ３ , MnTiO ３ , Nb ２ O ５ , and KTaO ３ 2. The active energy ray-curable composition according to claim 1, wherein the particles are at least one type selected from the group consisting of:

3. 2. The active energy ray-curable composition according to claim 1, wherein the monofunctional monomer (A1) is at least one monomer selected from the group consisting of alicyclic skeleton-containing (meth)acrylates, aromatic ring skeleton-containing (meth)acrylates, and heterocyclic skeleton-containing N-(meth)acrylamides.

4. 2. The active energy ray-curable composition according to claim 1, wherein the polyfunctional monomer (A2) is at least one monomer selected from the group consisting of alicyclic skeleton-containing di(meth)acrylates, aromatic ring skeleton-containing di(meth)acrylates, and heterocyclic skeleton-containing di(meth)acrylates.

5. 2. The active energy ray-curable composition according to claim 1, wherein the dispersant (E) is contained in an amount of 1% by weight to 20% by weight based on the total weight of the active energy ray-polymerizable compound (A), the inorganic particles (B), the photopolymerization initiator (C), and the dispersant (E).

6. 2. The active energy ray-curable composition according to claim 1, wherein the fatty acid having 12 to 36 carbon atoms has an HLB of 5 to 11.

7. A cured product of the active energy ray-curable composition according to any one of claims 1 to 6.

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