Active energy ray curable composition and cured product of same

Abstract

This active energy ray curable composition comprises a photopolymerizable compound (A), inorganic particles (B), and a photoinitiator (C). The active energy ray curable composition is characterized in that the photopolymerizable compound (A) includes a monofunctional monomer (A1) and a polyfunctional monomer (A2), the mean particle diameter of the inorganic particles (B) is 5-50 nm, the viscosity of the photopolymerizable compound (A) is 300 mPa·s or less at 25°C, and the glass transition temperature of a cured product of the photopolymerizable compound (A) is 70°C or higher.

Description

Active energy ray curable composition and cured product thereof

[0001] The present invention relates to an active energy ray-curable composition and a cured product thereof.

[0002] In recent years, high refractive index particles have been widely studied as fillers for anti-reflection materials, lens materials, high dielectric materials, etc. In particular, high refractive index particles with an average particle diameter of several nanometers to several tens of nanometers are highly valued due to their excellent transparency. Conventionally, particles such as zirconia and titania have been used for UV-curable resins (Patent Document 1). However, this technology does not have sufficient imprintability on glass, and it has been necessary to use a primer when imprinting on a glass substrate.

[0003] Japanese Patent Application Laid-Open No. 2019-6984

[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 imprintability.

[0005] The present inventors have conducted extensive research to solve these problems and have arrived at the present invention. Specifically, the present invention relates to an active energy ray-curable composition comprising a photopolymerizable compound (A), inorganic particles (B), and a photopolymerization initiator (C), wherein the photopolymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the inorganic particles (B) have an average particle size of 5 to 50 nm, the photopolymerizable compound (A) has a viscosity at 25°C of 300 mPa s or less, and a cured product of the photopolymerizable compound (A) has a glass transition temperature of 70°C or higher; and a cured product of the active energy ray-curable composition.

[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 imprintability.

[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 "curable composition of the present invention") is an active energy ray-curable composition containing a photopolymerizable compound (A), inorganic particles (B), and a photopolymerization initiator (C), wherein the photopolymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the inorganic particles (B) have an average particle size of 5 to 50 nm, the photopolymerizable compound (A) has a viscosity at 25°C of 300 mPa s or less, and a cured product of the photopolymerizable compound (A) has a glass transition temperature of 70°C or higher.

[0009] <Photopolymerizable Compound (A)> The photopolymerizable compound (A) will be described below. The photopolymerizable compound (A) is a compound that is cured by active energy rays, and is not particularly limited as long as it contains a monofunctional monomer (A1) and a polyfunctional monomer (A2). The photopolymerizable compound (A) may be used alone or in combination of two or more types. In this specification, "(meth)acrylate" means "acrylate and / or methacrylate". Furthermore, "(meth)acrylic" means "acrylic and / or methacrylic".

[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 (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, (meth)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 Acrylates, alicyclic skeleton-containing (meth)acrylates [for example, C6-C12 alicyclic skeleton-containing (meth)acrylates {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 hexahydrofuryl, acrylate, etc.}], aromatic ring skeleton-containing (meth)acrylates [for example, aromatic ring skeleton-containing (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), para-cumylphenoxyethyl (meth)acrylate, 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, and fluorene skeleton-containing mono(meth)acrylate compounds}, and the like.

[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. Examples of the organic monoisocyanate compound (b) include an aliphatic monoisocyanate compound (b1), an alicyclic monoisocyanate compound (b2), and an aromatic monoisocyanate compound (b3). Examples of the aliphatic monoisocyanate compound (b1) include methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, hexyl acrylate, octyl isocyanate, lauryl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate, and octadecyl isocyanate. Examples of the alicyclic monoisocyanate compound (b2) include cyclohexyl isocyanate. Examples of the aromatic monoisocyanate compound (b3) include phenyl isocyanate and tolylene isocyanate. The organic monoisocyanate compound (b) may be used alone or in combination of two or more.

[0013] The monofunctional urethane (meth)acrylate can be obtained by a known method of urethane reaction between a monofunctional (meth)acrylate (a) having a hydroxyl group and an organic monoisocyanate compound (b). Alternatively, commercially available products may be used, such as Viscoat #216 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Etermer EM2080 (manufactured by Choko Materials Industry Co., Ltd.), and Genomer 1122 (manufactured by RAHN).

[0014] 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). Examples of 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. Examples of 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 N-n-butoxymethylacrylamide, etc. N-hydroxyalkyl(meth)acrylamides include those having a hydroxyalkyl group having 1 to 6 carbon atoms, such as N-hydroxyethyl(meth)acrylamide, etc. The N,N-dialkyl(meth)acrylamide includes 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 N-n-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 (heterocyclic skeleton-containing N-(meth)acrylamides) include N-(meth)acryloylmorpholine, N-(meth)acryloylthiomorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, and N-(meth)acryloylpiperidine.

[0015] Examples of the monofunctional N-vinyl compound include N-vinylcaprolactam, N-vinylformamide, N-vinylimidazole, N-vinylacetamide, and heterocyclic skeleton-containing N-vinyl compounds (e.g., N-vinyl-2-pyrrolidone, 5-methyl-3-vinyl-2-oxazolidinone, N-vinylcarbazole, and N-vinylphthalimide).

[0016] 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 (meth)acrylates, aromatic ring skeleton-containing (meth)acrylates, and heterocyclic skeleton-containing N-(meth)acrylamides is more preferred. Specifically, the alicyclic skeleton-containing (meth)acrylate is preferably isobornyl acrylate, and the aromatic ring skeleton-containing (meth)acrylate is preferably phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, o-phenoxyphenylethyl acrylate, m-phenoxybenzyl acrylate, (naphthyl)methyl acrylate, benzyl acrylate, etc., and the heterocyclic skeleton-containing N-(meth)acrylamide is preferably N-(meth)acryloylmorpholine, etc. Particularly preferred are (meth)acrylates containing an aromatic ring skeleton, and specifically preferred are phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, o-phenoxyphenylethyl acrylate, m-phenoxybenzyl acrylate, (naphthyl)methyl acrylate, and benzyl acrylate.

[0017] Examples of the polyfunctional monomer (A2) include polyfunctional (meth)acrylate compounds and polyfunctional urethane (meth)acrylate compounds.

[0018] 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 containing 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 containing a fluorene skeleton (fluorene acrylate derivatives), monomers containing a biphenyl skeleton (4-biphenylmethyl acrylate, 1,1-biphenyl-2-yl acrylate, etc.), bis(4-ethenylthiobenzene)}, polyalkylene glycol di(meth)acrylates (dipropylene glycol diacrylate, etc.), alicyclic skeleton-containing di(meth)acrylates {for example, dimethylol-tricyclodecane di(meth)acrylate, bis(vinylsulfone)tricyclo[5.2.1.0]decane, etc.}, monomers containing a heterocyclic skeleton (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 di(meth)acrylates of AO adducts of dihydric phenol compounds include ethylene oxide of resorcinol (hereinafter, ethylene oxide may be abbreviated as "EO").di(meth)acrylate of an adduct of 4 moles of propylene oxide (hereinafter, propylene oxide may be abbreviated as "PO") to dihydroxynaphthalene, di(meth)acrylate of an adduct of 4 moles of EO to bisphenol A, di(meth)acrylate of an adduct of 10 moles of EO to bisphenol A, and di(meth)acrylate of an adduct of 20 moles of EO to bisphenol A.

[0019] Examples of the trifunctional (meth)acrylate 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].

[0020] Examples of the tetrafunctional (meth)acrylate 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).

[0021] Examples of the pentafunctional (meth)acrylate include dipentaerythritol penta(meth)acrylate and penta(meth)acrylates of AO adducts of dipentaerythritol (e.g., dipentaerythritol adducts with 2 mol of EO, 4 mol of EO, 10 mol of EO, and 15 mol of EO).

[0022] 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].

[0023] Examples of the polyfunctional urethane (meth)acrylate compound include bifunctional urethane (meth)acrylate, trifunctional urethane (meth)acrylate, tetrafunctional urethane (meth)acrylate, pentafunctional urethane (meth)acrylate, and hexafunctional or higher urethane (meth)acrylate. As the polyfunctional urethane (meth)acrylate, commercially available products may be used. Examples of commercially available products include Ebecryl 230, Ebecryl 8807, Ebecryl 9270, Ebecryl 8800, Ebecryl 4513, Ebecryl 680, Ebecryl 5129, KRM 8296, and KRM 8904 (all manufactured by Daicel Allnex Corporation).

[0024] Of the polyfunctional monomers (A2), polyfunctional (meth)acrylate compounds are preferred from the viewpoints of curability, refractive index, and cure shrinkage, and di- to hexa-functional (meth)acrylates are more preferred. Of the difunctional (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 mol of EO and adducts of trimethylolpropane with 9 mol of EO], pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, tetra(meth)acrylates of AO adducts of pentaerythritol [adducts of pentaerythritol with 2 mol of EO and adducts of pentaerythritol with 4 mol of EO], dipentaerythritol hexa(meth)acrylate, and hexa(meth)acrylates of AO adducts of dipentaerythritol [adducts of dipentaerythritol with 2 mol of EO and adducts of dipentaerythritol with 4 mol of EO].

[0025] 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.

[0026] From the viewpoint of low volatility, the photopolymerizable compound (A) preferably has a small content of monomers with a chemical formula weight of 230 or less, and more preferably has a small content of monomers with a chemical formula weight of 200 or less. The content of monomers with a chemical formula weight of 200 or less is preferably 50% by weight or less, more preferably 30% by weight or less, and particularly preferably 25% by weight or less, based on the weight of the photopolymerizable compound (A).

[0027] The monomer constituting the photopolymerizable compound (A) preferably contains a monomer having at least one aromatic ring, more preferably a monomer having two or more aromatic rings, from the viewpoint of the refractive index of the cured product, and more 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 reduction of cure shrinkage, the content of 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 in the photopolymerizable compound (A) is preferably 1 to 99 wt %, more preferably 10 to 80 wt %, based on the weight of the photopolymerizable compound (A).

[0029] The viscosity of the photopolymerizable compound (A) at 25°C is 300 mPa·s or less, preferably 1 to 200 mPa·s, and more preferably 50 to 150 mPa·s, from the viewpoint of imprintability. The viscosity of the photopolymerizable compound (A) at 25°C can be adjusted by the types and constituent ratios of the monomers constituting the photopolymerizable compound (A). The method for measuring the viscosity of the photopolymerizable compound (A) at 25°C is as follows. The viscosity of the photopolymerizable compound (A) at 25°C is measured based only on the composition of the photopolymerizable compound (A) constituting the active energy ray-curable composition. It does not depend on the inorganic particles (B), the photopolymerization initiator (C), or other components.

[0030] <Viscosity Measurement Method> The mixture of photopolymerizable compound (A) is kept at 25°C for 30 minutes, and the viscosity (mPa s) is measured using an E-type viscosity measuring device ["VISCOMETER TV-25L" manufactured by Toki Sangyo Co., Ltd.] under the following conditions. [Measurement Conditions] Cone rotor: Standard cone rotor (1°34' x R24) Measurement temperature: 25°C Measurement range: M Rotation speed: 50 rpm

[0031] From the viewpoint of heat resistance and adhesion, the glass transition temperature of the cured product of the photopolymerizable compound (A) is 70°C or higher, preferably 90°C or higher, more preferably 90 to 300°C, and even more preferably 90 to 250°C. The glass transition temperature of the cured product of the photopolymerizable compound (A) can be adjusted by the type and composition ratio of the monomers constituting the photopolymerizable compound (A). The glass transition temperature is the temperature at which the loss tangent (tan δ) reaches its maximum value when the dynamic viscoelasticity of a polymer obtained by polymerizing the photopolymerizable compound (A) by the method described below is measured by the method described below. The glass transition temperature of the cured product of the photopolymerizable compound (A) is measured based solely on the composition of the photopolymerizable compound (A) constituting the active energy ray-curable composition. It is not dependent on the inorganic particles (B), the photopolymerization initiator (C), or other components.

[0032] <Preparation of Test Piece> (1) 1-hydroxycyclohexyl phenyl ketone [trade name "Irgacure 184", manufactured by BASF] as a photoradical polymerization initiator was added to the photopolymerizable compound (A) at 3 wt % and stirred until uniform to prepare a test piece sample. (2) Two 1 mm thick silicone rubber sheets [trade name: Silicone Rubber Sheet, manufactured by AS ONE Corporation] cut to a width of 10 mm and a length of 150 mm were attached to both ends of a glass plate [trade name: GLASS PLATE, manufactured by AS ONE Corporation, length 200 mm x width 200 mm x thickness 5 mm], approximately 5 g of the prepared test piece sample was placed between the silicone rubber sheets, and a PET film [trade name: Lumirror S, manufactured by Toray Industries, Inc.] was placed on top to prevent air from entering, and then a glass plate was placed on top. (3) (2) is exposed to an ultraviolet irradiation device (e.g., VPS / I600 manufactured by Fusion UV Systems Japan, Inc., lamp: D bulb) at an illuminance of 1500 mW / cm in an environment of 25°C. ２ (UV-A) 1000mJ / cm ２ Then, (2) was turned over and irradiated from the other side with 1000 mJ / cm ２ (4) The cured sample of (3) is cut into a length of 40 mm, a width of 5 mm, and a thickness of 1 mm to prepare a test piece.

[0033] <Dynamic viscoelasticity measurement method> Using this test piece, measurement is performed using a dynamic viscoelasticity measurement device (for example, Rheogel-E4000, manufactured by UBM) under the following conditions: Measurement mode: temperature dependency, Measurement temperature range: -80°C to 350°C, Frequency: 10 Hz, Heating rate: 4°C / min, Distortion waveform: Sine wave, Measurement jig: Tensile. The temperature at which the ratio of the loss modulus E" to the storage modulus E' (loss tangent tan δ) in the obtained spectrum shows a maximum value is defined as the glass transition temperature (Tg).

[0034] As a method for adjusting the glass transition temperature, in order to increase the glass transition temperature, for example, a method of using a photopolymerizable compound (A) having a high glass transition temperature of a homopolymer, or a method of increasing the number of functional groups can be mentioned.

[0035] From the viewpoint of the refractive index of the cured product, the refractive index of the photopolymerizable compound (A) is preferably 1.50 or higher, more preferably 1.55 or higher, and particularly preferably 1.60 or higher. However, a photopolymerizable compound with a refractive index of less than 1.50 may be used in combination, as long as it does not affect the decrease in refractive index. The refractive index of the photopolymerizable compound (A) is a value measured at 25°C in an uncured state using the D line of the sodium spectrum with an Abbe refractometer [DR-M2 manufactured by Atago Co., Ltd., etc.] in accordance with JIS-K0062:1992. The refractive index of the photopolymerizable compound (A) is measured based solely on the composition of the photopolymerizable compound (A) constituting the active energy ray-curable composition. It is not dependent on the inorganic particles (B), photopolymerization initiator (C), or other components.

[0036] <Inorganic Particles (B)> The inorganic particles (B) are described below. There are no particular limitations on the inorganic particles (B) as long as they are particles of an inorganic compound with an average particle size of 5 to 50 nm. Examples include compounds of metal elements and compounds of nonmetal elements, and examples of such compounds include hydrogen compounds, oxides, oxoacids, hydroxides, halides, sulfates, nitrates, carbonates, acetates, and metal complexes. Of the above inorganic compounds, oxides of metal elements, oxides of nonmetal elements, and oxides containing metal elements and nonmetal elements are preferred from the viewpoint of refractive index. One type of inorganic particle (B) may be used alone, or two or more types may be used in combination.

[0037] As the oxide particles as the inorganic particles (B), from the viewpoint of refractive index, 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 O５ , and KTaO ３ At least one type of particle selected from the group consisting of:

[0038] The average particle size of the inorganic particles (B) is 5 to 50 nm, because this provides excellent dispersion stability and a cured product with high light transmittance and refractive index. In the present invention, the average particle size of the inorganic particles (B) is the average primary particle size measured from approximately 300 particles in a photograph (25k) observed with a transmission electron microscope (JEOL Ltd., JEM-F200). Here, the average primary particle size is the particle size calculated by averaging the diameter of a circle having an area equivalent to the area determined for each particle from the photograph (circle-equivalent diameter) over all measured particles. Furthermore, the average particle size of the inorganic particles (B) is preferably 5 to 40 nm.

[0039] The shape of the inorganic particles (B) is not particularly limited, but may be, for example, spherical, hollow, porous, rod-like, plate-like, fibrous, or amorphous. Among them, spherical is preferred because it provides excellent dispersion stability and a cured product with high light transmittance and refractive index. The crystal structure of the inorganic particles (B) is also not particularly limited, but monoclinic is preferred because it provides excellent dispersion stability and a cured product with high light transmittance and refractive index.

[0040] <Photopolymerization initiator (C)> The photopolymerization initiator (C) will be described 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 a benzoin compound (C1), an alkylphenone compound (C2), an anthraquinone compound (C3), a thioxanthone compound (C4), a ketal compound (C5), a benzophenone compound (C6), a phosphine oxide (C7), and an oxime ester compound (C8).

[0041] 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 compounds (C3) include 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone. Examples of the thioxanthone compounds (C4) include 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone. Examples of the ketal compounds (C5) include acetophenone dimethyl ketal and benzyl dimethyl ketal. Examples of the benzophenone compounds (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).

[0042] Among these photopolymerization initiators (C), 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 are preferred from the viewpoint of curability. One type of photopolymerization initiator (C) may be used alone, or two or more types may be used in combination.

[0043] From the viewpoint of stability, the active energy ray-curable composition of the present invention preferably contains a dispersant (D). The dispersant (D) is a surfactant containing at least one functional group selected from the group consisting of a carboxyl group, a phosphate group, a thiol group, a hydroxyl group, and an amino group, and it adsorbs to the surfaces of inorganic particles to uniformly disperse the inorganic particles in the cured product.

[0044] Examples of surfactants containing a carboxyl group include saturated fatty acids having 12 to 36 carbon atoms (lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, isostearic acid, etc.) and / or salts thereof, monocarboxylic acids of alkylene oxide adducts (polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, etc.) and / or salts thereof, compounds having a (meth)acryloyloxy group or a vinyl group and a carboxyl group (carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone mono(meth)acrylate, monohydroxyethyl phthalate (meth)acrylate, 2-acryloyloxyethyl succinate, 2-methacryloyloxyethyl succinate, 2-acryloyloxyethyl hexahydrophthalate, 2-methacryloyloxyethyl hexahydrophthalate, etc.) and salts thereof. Examples of surfactants containing a phosphate group include alkyl phosphate esters having 4 to 36 carbon atoms (2-ethylhexyl acid phosphate, oleyl acid phosphate, etc.) and / or salts thereof, phosphate esters of alkylene oxide adducts (butoxyethyl acid phosphate, etc.) and salts thereof, and compounds having a (meth)acryloyloxy group or a vinyl group and a phosphate group (2-methacryloyloxyethyl caproate acid phosphate, acid phosphoxypropylene glycol monomethacrylate, and 2-methacryloyloxyethyl acid phosphate (2-hydroxyethyl methacrylate acid phosphate) and salts thereof. Examples of surfactants containing a thiol group include alkyl thiols having 8 to 36 carbon atoms (1-dodecanethiol, etc.) and aromatic thiols (2-mercaptobenzothiazole, etc.).Examples of surfactants containing a hydroxyl group include saturated alcohols having 8 to 36 carbon atoms (such as octanol, decanol, octadecanol, docosanol, and triacontanol), alkylene oxide adducts of saturated alcohols having 8 to 36 carbon atoms (such as polyethylene glycol monolaurate), sorbitan fatty acid esters (such as sorbitan monostearate and sorbitan monolaurate), and compounds having a (meth)acryloyloxy group or a vinyl group and a hydroxyl group (such as hydroxyethyl (meth)acrylate, 4-hydroxybutyl acrylate, N-(2-hydroxyethyl)acrylamide, and 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid). Examples of surfactants containing an amino group include amine compounds having 8 to 36 carbon atoms (such as N,N-dimethyldodecylamine), and compounds having a (meth)acryloyloxy group or a vinyl group and an amino group (such as 2-(dimethylamino)ethyl methacrylate and N-[3-(dimethylamino)propyl]acrylamide).

[0045] Of these dispersants (D), preferred from the viewpoint of dispersion stability are surfactants containing a carboxyl group, surfactants containing a phosphate group, or surfactants containing a hydroxyl group, more preferred are compounds having a (meth)acryloyloxy group or a vinyl group and a carboxyl group, compounds having a (meth)acryloyloxy group or a vinyl group and a phosphate group, and compounds having a (meth)acryloyloxy group or a vinyl group and a hydroxyl group, and particularly preferred are carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone mono(meth)acrylate, and monohydroxyethyl phthalate. (Meth)acrylate, 2-acryloyloxyethyl succinate, 2-methacryloyloxyethyl succinate, 2-acryloyloxyethyl hexahydrophthalate and 2-methacryloyloxyethyl hexahydrophthalate, 2-methacryloyloxyethyl caproate acid phosphate, acid phosphooxypropylene glycol monomethacrylate, 2-methacryloyloxyethyl acid phosphate (2-hydroxyethyl methacrylate acid phosphate), hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and N-(2-hydroxyethyl)acrylamide.

[0046] The active energy ray-curable composition of the present invention can be diluted with a solvent (E) as necessary, as long as the effects of the present invention are not impaired. From the viewpoints of compatibility with other components and dispersibility, the solvent (E) is preferably an organic solvent. Examples of such organic solvents include alcohols (methanol, ethanol, isopropanol, butanol, 3-methoxybutanol, octanol, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.); 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, etc.); ethers (ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, etc.); aromatic hydrocarbons (benzene, toluene, xylene, etc.); and amides (dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.). Among 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, methoxybutyl acetate, toluene, and xylene are preferred. The solvent (E) may be used alone or in combination of two or more.

[0047] 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 the additives include a mold 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).

[0048] Examples of the mold release agent (F) include fluorine additives, acrylic leveling agents, silicone leveling agents, etc. Examples of fluorine additives include BM-1000 and BM-1100 (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 (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 (manufactured by AGC Seimi Chemical Co., Ltd.). Examples of acrylic leveling agents include Disparlon UVX-36 (manufactured by Kusumoto Chemical 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 mold release agent (F) may be used alone or in combination of two or more.

[0049] The refractive index of the active energy ray-curable composition of the present invention is preferably 1.60 to 1.80 from the viewpoint of improving the brightness of the optical lens.

[0050] The viscosity of the active energy ray-curable composition of the present invention at 25°C is preferably 300 mPa·s or less from the viewpoint of the coatability of the active energy ray-curable composition and the imprintability of the cured product. The viscosity of the active energy ray-curable composition of the present invention at 25°C can be measured under the following conditions using an E-type viscosity measuring device ["VISCOMETER TV-25L" manufactured by Toki Sangyo Co., Ltd.] or the like. [Measurement conditions] Cone rotor: Standard cone rotor (1°34' x R24) Measurement temperature: 25°C Measurement range: M Rotation speed: 50 rpm

[0051] The weight proportion of the photopolymerizable compound (A) in the present invention is preferably 3 to 50% by weight, more preferably 4 to 30% by weight, based on the total weight of the photopolymerizable compound (A), inorganic particles (B), and photopolymerization initiator (C). If the weight proportion of the photopolymerizable compound (A) is less than 3% by weight, the imprintability may be insufficient, and if it exceeds 50% by weight, the refractive index of the cured product may be insufficient.

[0052] The weight proportion of the inorganic particles (B) in the present invention is preferably 49 to 96% by weight, more preferably 69 to 95% by weight, based on the total weight of the photopolymerizable compound (A), the inorganic particles (B), and the photopolymerization initiator (C). If the weight proportion of the inorganic particles (B) is less than 49% by weight, the refractive index of the cured product may be insufficient, and if it exceeds 96% by weight, the imprintability may be insufficient.

[0053] 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 photopolymerizable compound (A), the inorganic particles (B), and the photopolymerization initiator (C).

[0054] The weight proportion of the dispersant (D) 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 photopolymerizable compound (A) and the inorganic particles (B).

[0055] The weight proportion of the solvent (E) in the present invention is preferably 0 to 800% by weight, more preferably 0.1 to 700% by weight, and particularly preferably 1 to 500% by weight, based on the total weight of the photopolymerizable compound (A), the inorganic particles (B), and the photopolymerization initiator (C).

[0056] In the present invention, the weight proportion of the other additives (excluding the solvent (E)) is preferably 0.01 to 10% by weight based on the total weight of the photopolymerizable compound (A), inorganic particles (B), and photopolymerization initiator (C), from the viewpoint of the refractive index of the cured product.

[0057] The active energy ray-curable composition of the present invention can be produced, for example, by uniformly mixing the photopolymerizable compound (A), inorganic particles (B), photopolymerization initiator (C), dispersant (D), solvent (E), and other additives using a known mechanical mixing method (such as a method using a mechanical stirrer or a magnetic stirrer). The inorganic particles (B) may be dispersed in an organic solvent (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, or propylene glycol monomethyl ether acetate). In this case, a mixture of the active energy ray-curable composition of the present invention and the organic solvent is obtained. Furthermore, the organic solvent may be distilled off under reduced pressure to adjust the weight ratio of the organic solvent to a desired amount.

[0058] <Cured Product> The cured product of the present invention is obtained by curing the active energy ray-curable composition of the present invention, 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 it. Examples of active energy rays include visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, γ-rays, and electron beams. Ultraviolet light refers to light rays with a wavelength of 200 nm to 410 nm. The wavelength of the active energy rays is not particularly limited as long as it can cure the composition, but is preferably 350 nm to 410 nm, and more preferably 385 nm to 405 nm. A representative example of active energy rays is light with a wavelength of 395 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 ~20000mW / cm ２ The cumulative exposure dose of the active energy ray is preferably 100 mJ / cm ２ ~30000mJ / cm ２ The irradiation time may be determined depending on the irradiation intensity.

[0059] When ultraviolet rays are used as the active energy rays, 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. Among these, LEDs consume less power and generate less ozone than other light sources, have lower running costs, and are less environmentally hazardous. When curing with an LED light source, an LED light source ultraviolet irradiation device [for example, LED light source ultraviolet irradiation device "FJ100" 150 x 20 365, manufactured by Phoseon Technology Co., Ltd.] can be used.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] The refractive index of the cured product of the present invention is preferably 1.60 or more, more preferably 1.60 to 1.80, from the viewpoint of improving the brightness of the optical lens.

[0064] 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 part (optical lens, sheet for optical lens, film, coating material for decorative film, coating material for optical fiber, hard coat film, antireflection film, etc.).

[0065] 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 the optical component can be coated and molded, for example, 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 against 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.

[0066] 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.

[0067] The present specification describes the following: <1> An active energy ray-curable composition comprising a photopolymerizable compound (A), inorganic particles (B), and a photopolymerization initiator (C), wherein the photopolymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the inorganic particles (B) have an average particle size of 5 to 50 nm, the photopolymerizable compound (A) has a viscosity of 300 mPa s or less at 25°C, and a cured product of the photopolymerizable compound (A) has a glass transition temperature of 70°C or higher. <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 ２O ５ , and KTaO ３ The active energy ray-curable composition according to <1>, wherein the photopolymerizable compound (A) contains a monomer having a chemical formula weight of 200 or less, and the content of the monomer having a chemical formula weight of 200 or less is 50% by weight or less based on the weight of the photopolymerizable compound (A). <4> The active energy ray-curable composition according to any one of <1> to <3>, wherein the monofunctional monomer (A1) is at least one monomer selected from the group consisting of an alicyclic skeleton-containing (meth)acrylate, an aromatic ring skeleton-containing (meth)acrylate, and a heterocyclic skeleton-containing N-(meth)acrylamide. <5> The active energy ray-curable composition according to any one of <1> to <4>, wherein the polyfunctional monomer (A2) is at least one monomer selected from the group consisting of an alicyclic skeleton-containing di(meth)acrylate, an aromatic ring skeleton-containing di(meth)acrylate, and a heterocyclic skeleton-containing di(meth)acrylate. <6> The active energy ray-curable composition according to any one of <1> to <5>, further comprising a dispersant (D), wherein the dispersant (D) is a surfactant containing at least one functional group selected from the group consisting of a carboxyl group, a phosphate group, a thiol group, a hydroxyl group, and an amino group. <7> A cured product of the active energy ray-curable composition according to any one of <1> to <6>. <8> The cured product according to <7>, which has a refractive index of 1.60 or more.

[0068] 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.

[0069] <Preparation of active energy ray-curable compositions> (Examples 1 to 9 and Comparative Examples 1 to 3) According to the blending parts (parts by weight) in Table 1, the photopolymerizable compound (A), inorganic particles (B), photopolymerization initiator (C), dispersant (D), solvent (E) and mold release agent (F) were charged into a glass container and stirred until homogeneous, thereby obtaining active energy ray-curable compositions of Examples 1 to 9 and Comparative Examples 1 to 3.

[0070]

[0071] The raw materials used in Table 1 are as follows:

[0072] (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): Benzyl acrylate [Viscoat #160: manufactured by Osaka Organic Chemical Industry Co., Ltd., refractive index (25°C): 1.51] (A-6): Neopentyl glycol diacrylate [NP-A: Kyoeisha Chemical Co., Ltd., refractive index (25°C): 1.45] (A-7): Dimethylol-tricyclodecane diacrylate [Light Acrylate DCP-A: Kyoeisha Co., Ltd., refractive index (25°C): 1.50] (A-8): Dimethylol-tricyclodecane dimethacrylate [DCP: Shin-Nakamura Chemical Co., Ltd., refractive index (25°C): 1.50] (A-9): A 40:60 blend of acrylic-modified bisphenoxyethanol fluorene and o-phenoxyphenyl ethyl acrylate [Etermer EM2206: Eternal Materials, refractive index (25°C): 1.59] (A-10): 1,4-butanediol diacrylate [Viscoat #195: manufactured by Osaka Organic Chemical Industry Co., Ltd., refractive index (25°C): 1.46] (A-11): dipropylene glycol diacrylate [Miramer M222: manufactured by Miwon Co., Ltd., refractive index (25°C): 1.45] (A-12): ethoxylated bisphenol A diacrylate [Neomer BA-641: manufactured by Sanyo Chemical Industries, Ltd., refractive index (25°C): 1.54] (A-13): 4,4'-bisacryloxymethylbiphenyl [DABP: manufactured by JFE Chemical Corporation, refractive index (25°C): 1.59] (A-14): pentaerythritol tetraacrylate [Neomer EA-300: manufactured by Sanyo Chemical Industries, Ltd., refractive index (25°C): 1.48] (A-15): dipentaerythritol hexaacrylate [Neomer DA-600: manufactured by Sanyo Chemical Industries, Ltd., refractive index (25°C): 1.47] Note that (A-9) is a mixture of acrylic-modified bisphenoxyethanol fluorene, which is the polyfunctional monomer (A2), and o-phenoxyphenylethyl acrylate, which is the monofunctional monomer (A1), but is shown in the section for polyfunctional monomer (A2) in Table 1.

[0073] (B-1): Zirconium oxide (ZrO ２ (B-1): a solution of titanium dioxide (TiO) particles dispersed in methyl ethyl ketone [product name "Zircostar AX-ZP-158-A, solid content: 70 wt %, average particle size of zirconia particles: 17 nm", manufactured by Nippon Shokubai Co., Ltd.] ２ ) particles [trade name "TTO-51(C), average particle diameter of titanium oxide particles 10-30 nm", manufactured by Ishihara Sangyo Kaisha, Ltd.] (B-3): barium titanate (BaTiO ３ ) particles dispersed in propylene glycol monomethyl ether [product name "9714BT, solid content: 15 wt %, average particle diameter of barium titanate particles: approximately 40 nm, manufactured by Tokushiki Co., Ltd.]

[0074] (C-1): 2,4,6-trimethylbenzoyldiphenylphosphine oxide [trade name "IRGACURE TPO", manufactured by BASF] (C-2): Omnirad TPO-L [2,4,6-trimethylbenzoylethylphenylphosphine oxide, manufactured by IGM Resins B.V.] (C-3): 1-hydroxycyclohexyl phenyl ketone [trade name "Irgacure 184", manufactured by BASF]

[0075] (D-1): 2-acryloyloxyethyl hexahydrophthalate [HOA-HH: Kyoeisha Chemical Co., Ltd., HLB: 11.4] (D-2): 2-acryloyloxyethyl succinate [HOA-MS: Kyoeisha Chemical Co., Ltd., HLB: 15.2] (D-3): acrylic oligomer [(ACA) Z200M: manufactured by Daicel Allnex Co., Ltd.] (D-4): 2-methacryloyloxyethyl caproate acid phosphate [KAYAMER PM-21: manufactured by Nippon Kayaku Co., Ltd., HLB: 5.3] (D-5): acid phosphooxypropylene glycol monomethacrylate [Phosmer PP: manufactured by Unichemical Co., Ltd., HLB: 5.1] (D-6): 2-mercaptobenzothiazole [Suncerer M: manufactured by Sanshin Chemical Industry Co., Ltd., HLB: 2.0] (D-7): N-(2-hydroxyethyl)acrylamide [HEAA: manufactured by KJ Chemicals Co., Ltd., HLB: 30.2] (D-8): N-[3-(dimethylamino)propyl]acrylamide [DMAPAA: manufactured by KJ Chemicals Co., Ltd., HLB: 17]

[0076] (E-1): PGMEA [2-methoxy-1-methylethyl acetate: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.] (E-2): MEK [methyl ethyl ketone: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.] (E-3): cyclohexanone [manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.] (E-4): MBA [3-methoxybutyl acetate: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.]

[0077] (F-1): Fluorine additive [F-444: manufactured by DIC Corporation]

[0078] For the active energy ray-curable compositions prepared in each of the Examples and Comparative Examples, the viscosity of the photopolymerizable compound (A), the glass transition temperature (Tg) of the cured product of the photopolymerizable compound (A), the refractive index and adhesion of the cured product of the active energy ray-curable composition, and the imprintability and dispersion stability of the active energy ray-curable composition were evaluated by the following methods.

[0079] <Measurement of Viscosity of Photopolymerizable Compound (A)> The mixtures of photopolymerizable compound (A) used in Examples 1 to 9 and Comparative Examples 1 to 3 were kept at 25°C for 30 minutes, and the viscosity (mPa·s) was measured under the following conditions using an E-type viscosity measuring device ["VISCOMETER TV-25L" manufactured by Toki Sangyo Co., Ltd.]. In the present invention, the viscosity must be 300 mPa·s or less. [Measurement Conditions] Cone rotor: Standard cone rotor (1°34' x R24) Measurement temperature: 25°C Measurement range: M Rotation speed: 50 rpm

[0080] <Measurement of Glass Transition Temperature of Cured Product of Photopolymerizable Compound (A)> (1) 3 wt % of 1-hydroxycyclohexyl phenyl ketone (trade name "Irgacure 184", manufactured by BASF) as a photoradical polymerization initiator was added to the mixture of photopolymerizable compound (A) used in Examples 1 to 9 and Comparative Examples 1 to 3, and the mixture was stirred until homogeneous to prepare a test piece sample. (2) Two 1 mm thick silicone rubber sheets (trade name: Silicone Rubber Sheet, manufactured by AS ONE Corporation) cut to a width of 10 mm and a length of 150 mm were attached to both ends of a glass plate (trade name: GLASS PLATE, manufactured by AS ONE Corporation, 200 mm length x 200 mm width x 5 mm thickness), and approximately 5 g of the prepared test piece sample was placed between the silicone rubber sheets. A PET film (trade name: Lumirror S, manufactured by Toray Industries, Inc.) was then placed on top to prevent air from entering, and a glass plate was then placed on top. (3) (2) was exposed to an ultraviolet irradiation device (VPS / I600 manufactured by Fusion UV Systems Japan, Inc., lamp: D bulb) at an illuminance of 1500 mW / cm under an environment of 25°C. ２ (UV-A) 1000mJ / cm ２ Then, (2) was turned over and irradiated from the other side with 1000 mJ / cm ２(4) The cured sample of (3) was cut into a length of 40 mm, a width of 5 mm, and a thickness of 1 mm to prepare a test piece. (5) Using the above test piece, a dynamic viscoelasticity measuring device (Rheogel-E4000, manufactured by UBM) was used to measure under the following conditions: Measurement mode: temperature dependence, Measurement temperature range: -80°C to 350°C, Frequency: 10 Hz, Heating rate: 4°C / min, Distortion waveform: Sine wave, Measurement jig: Tensile. The temperature at which the ratio of the loss modulus E" to the storage modulus E' in the obtained spectrum (loss tangent tanδ) showed a maximum value was defined as the glass transition temperature (Tg).

[0081] <Method for producing a cured product for evaluating refractive index and adhesion> The active energy ray-curable composition was dropped onto a glass substrate [Eagle XG, manufactured by Corning Co., Ltd.] and applied by spin coating at 3000 rpm for 30 seconds, and then dried at 100°C for 3 minutes. After that, ultraviolet light was irradiated at 1000 mJ / cm using an ultraviolet light 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 having a film thickness of 100 nm for refractive index evaluation.

[0082] <Refractive Index> The refractive index of the cured product prepared as described above at 589 nm was measured using a reflection spectroscopic film thickness meter [FE-3000, manufactured by Otsuka Electronics Co., Ltd.]. In this case, a refractive index of 1.60 or higher is considered to be satisfactory.

[0083] <Method for evaluating adhesion> For the cured product for evaluation, cellophane adhesive tape was applied to the surface of the cured product and peeled off at an angle of 90 degrees. The state of peeling of the cured product from the glass was visually observed and evaluated according to the following criteria: ◎: 90% or more of the cured product remains on the glass substrate ○: 50% to less than 90% of the cured product remains on the glass substrate ×: Less than 50% of the cured product remains on the glass substrate

[0084] <Method for evaluating imprintability> (1) The active energy ray-curable composition was dropped onto a glass substrate [Eagle XG, manufactured by Corning Co., Ltd.] and applied by spin coating at a rotation speed of 500 rpm for 30 seconds, followed by drying 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 the mold to push out air. UV rays were irradiated 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 (3) The mold from (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 were transferred visually. ◯: 30% to less than 80% of the irregularities were transferred visually. ×: Less than 30% of the irregularities were transferred visually.

[0085] <Method for evaluating dispersion stability> The active energy ray-curable composition was stored at 25°C for one week, one month, or three months. Whether the dispersion state of the particles was maintained after storage was evaluated. If there was no visible change and the particles did not settle for one week but settled or gelled within one month, the evaluation was rated "Good." If the particles did not settle for one month but settled or gelled within three months, the evaluation was rated "Excellent." If the particles did not settle for three months, the evaluation was rated "Excellent." If the coated particles settled within one week, or if there was a clear increase in viscosity and gelled, the evaluation was rated "Poor."

[0086] As can be seen from the results in Table 1, Comparative Examples 1 and 3, which used active energy ray-curable compositions in which the glass transition temperature of the photopolymerizable compound (A) was outside the range specified by the present invention, showed low adhesion and poor imprintability. Furthermore, Comparative Example 2, which used an active energy ray-curable composition in which the viscosity of the photopolymerizable compound (A) was outside the range specified by the present invention, showed poor imprintability. In contrast, each of the Examples provided cured products that showed good results in all aspects.

[0087] 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 a photopolymerizable compound (A), inorganic particles (B), and a photopolymerization initiator (C), wherein the photopolymerizable compound (A) contains a monofunctional monomer (A1) and a polyfunctional monomer (A2), the inorganic particles (B) have an average particle size of 5 to 50 nm, the photopolymerizable compound (A) has a viscosity at 25°C of 300 mPa s or less, and a cured product of the photopolymerizable compound (A) has a glass transition temperature of 70°C or higher.

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. The active energy ray-curable composition according to claim 1, wherein the photopolymerizable compound (A) contains a monomer having a chemical formula weight of 200 or less, and the content of the monomer having a chemical formula weight of 200 or less is 50% by weight or less based on the weight of the photopolymerizable compound (A).

4. 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.

5. 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.

6. The active energy ray-curable composition according to claim 1, further comprising a dispersant (D), wherein the dispersant (D) is a surfactant containing at least one functional group selected from the group consisting of a carboxyl group, a phosphate group, a thiol group, a hydroxyl group, and an amino group.

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

8. The cured product according to claim 7, which has a refractive index of 1.60 or more.

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