Active energy ray-curable composition and cured product thereof

Abstract

An active energy ray-curable composition according to the present invention comprises: an active energy ray-polymerizable compound (A) which is a monomer having a carbon-carbon double bond and having a refractive index of 1.59 or more; inorganic particles (B); and a photopolymerization initiator (C). The active energy ray-curable composition may comprise an active energy ray-polymerizable compound (A') which is a monomer having a carbon-carbon double bond and having a refractive index of less than 1.59. The inorganic particles (B) have a number average particle diameter of 5 to 50 nm and have a refractive index of 2.2 to 2.5. A mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') has a viscosity of 300 mPa·s or less at 25°C.

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, and the like. High-refractive-index particles with particle diameters of several nanometers to several tens of nanometers are particularly popular due to their excellent transparency. Conventionally, particles of zirconia, titania, and the like have been used for UV-curable resins (see Patent Document 1). However, with these techniques, the refractive index of the cured product and the imprintability (transferability of microstructures) of the composition before curing may be insufficient, and coloring of the cured product may occur upon light irradiation. Improvements in these areas are desired.

[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 that can give a cured product having a high refractive index and light resistance and that is excellent in imprintability.

[0005] The present inventors have conducted extensive research to solve these problems and have arrived at the present invention. That is, the present invention relates to an active energy ray-curable composition comprising an active energy ray-polymerizable compound (A) which is a monomer having a carbon-carbon double bond and a refractive index of 1.59 or more, inorganic particles (B), and a photopolymerization initiator (C), and may also comprise an active energy ray-polymerizable compound (A') which is a monomer having a carbon-carbon double bond and a refractive index of less than 1.59, wherein the inorganic particles (B) are particles having a number average particle diameter of 5 to 50 nm and a refractive index of 2.2 to 2.5, and a mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') has a viscosity of 300 mPa s or less at 25°C; 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 can give a cured product having a high refractive index and light resistance and that has excellent 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") comprises an active energy ray-polymerizable compound (A) which is a monomer having an active carbon-carbon double bond and has a refractive index of 1.59 or more, inorganic particles (B), and a photopolymerization initiator (C), and may also comprise an active energy ray-polymerizable compound (A') which is a monomer having a carbon-carbon double bond and has a refractive index of less than 1.59, the inorganic particles (B) being particles having a number average particle diameter of 5 to 50 nm and a refractive index of 2.2 to 2.5, and the viscosity of a mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') at 25°C is 300 mPa s or less.

[0009] <Active Energy Ray-Polymerizable Compound (A)> The active energy ray-polymerizable compound (A) will be described below. The active energy ray-polymerizable compound (A) is a compound that polymerizes when exposed to active energy rays, and is not particularly limited as long as it is a monomer having a carbon-carbon double bond and a refractive index of 1.59 or more. 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 rays having a wavelength of 200 nm to 410 nm.

[0010] The carbon-carbon double bond is a bond that polymerizes when exposed to active energy rays. Preferred examples of the group having a carbon-carbon double bond include functional groups having an ethylenically unsaturated bond, such as a vinyl group, an allyl group, a butenyl 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. 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." The active energy ray-polymerizable compound (A) may be used alone or in combination of two or more types.

[0011] The refractive index of the active energy ray-polymerizable compound (A) is 1.59 or more, preferably 1.59 to 1.80. If the refractive index is less than 1.59, the refractive index of the active energy ray-curable composition will be low. The refractive index can be controlled by adjusting the amount of molecules containing atoms with different atomic refractions. The refractive indexes of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') described below are values ​​measured by the Abbe method (critical angle method) at a wavelength of 589 nm (D-ray) and a measurement temperature of 25°C, with reference to JIS K0062.

[0012] Examples of the active energy ray-polymerizable compound (A) include alicyclic skeleton monomers, aromatic skeleton monomers, and heterocyclic skeleton monomers.

[0013] Examples of the alicyclic skeleton monomer include bis(vinylsulfone)tricyclo[5.2.1.0]decane.

[0014] Examples of the aromatic ring skeleton monomer include monomers containing a naphthalene skeleton [(1-naphthyl)methyl acrylate, (2-naphthyl)methyl acrylate, binaphthol derivatives such as 2,2'-diacryloxy-1,1'-binaphthalene (BINLA) and 2,2'-diallyloxy-1,1'-binaphthalene (DAOBINL), and naphthothiol derivatives such as 1,6-bisvinylthionaphthalene (16DVNDSH)], monomers containing a fluorene skeleton (fluorene acrylate derivatives such as OGSOL EA-0200), monomers containing a biphenyl skeleton (4-biphenylmethyl acrylate, 1,1-biphenyl-2-yl acrylate, 4,4'-bisacryloxymethylbiphenyl), and monomers containing a diphenyl sulfide skeleton [bis(4-methacryloylthiophenyl)sulfide, 1,1'-thiobis(4-ethenylthiobenzene)].

[0015] Examples of the heterocyclic skeleton monomer include sulfur atom-containing monomers [monomers containing a thiophene skeleton (e.g., dinaphthothiophene derivatives such as 6-hydroxymethyldinaphthothiophene acrylate (6MDNTA)], and nitrogen atom-containing monomers (e.g., monomers containing a pyridazine skeleton).

[0016] Among the active energy ray-polymerizable compounds (A), from the viewpoints of curability, refractive index, and light resistance, aromatic ring skeleton monomers and / or heterocyclic ring skeleton monomers are preferred, and monomers containing at least one skeleton selected from the group consisting of a naphthalene skeleton, a thiophene skeleton, a biphenyl skeleton, and a diphenyl sulfide skeleton are more preferred. Furthermore, the number of aromatic rings or heterocyclic rings in the molecule of the active energy ray-polymerizable compound (A) is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to 2.

[0017] The active energy ray-curable composition of the present invention may contain, if necessary, an active energy ray-polymerizable compound (A′) which is a monomer having a carbon-carbon double bond and has a refractive index of less than 1.59, other than the active energy ray-polymerizable compound (A), within a range that does not impair the effects of the present invention.

[0018] The active energy ray-polymerizable compound (A') is an active energy ray-polymerizable compound having a refractive index of less than 1.59, and examples thereof include (meth)acrylate monomers (phenoxyethyl acrylate, benzyl acrylate, o-phenoxyphenylethyl acrylate, m-phenoxybenzyl acrylate, dimethylol-tricyclodecane di(meth)acrylate, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate).

[0019] In the active energy ray-curable composition of the present invention, the viscosity of the mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') at 25°C is 300 mPa·s or less. The viscosity of the mixture is preferably 1 to 200 mPa·s, more preferably 50 to 150 mPa·s. If the viscosity exceeds 300 mPa·s, the imprintability deteriorates. When two or more monomers are used in combination as the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A'), the viscosity of the monomer mixture at 25°C is also 300 mPa·s or less. The viscosity of the monomer mixture at 25°C can be adjusted by the type and blending ratio of the monomers.

[0020] In the active energy ray-curable composition of the present invention, the active energy ray-polymerizable compound (A') is an optional component. When the active energy ray-curable composition of the present invention does not contain the active energy ray-polymerizable compound (A'), the viscosity of the active energy ray-polymerizable compound (A) is taken to be the viscosity of a mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A'). In this specification, when the active energy ray-curable composition does not contain the active energy ray-polymerizable compound (A'), the active energy ray-polymerizable compound (A) is treated as a mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A').

[0021] The viscosity of the mixture at 25°C is a value measured with reference to JIS Z8803. The specific measurement method is as follows. [Viscosity measurement method] A mixture of active energy ray polymerizable compound (A) and active energy ray polymerizable compound (A') is kept at 25°C for 30 minutes, and the viscosity (mPa s) is measured under the following conditions using an E-type viscosity measuring device ["VISCOMETER TV-25L" manufactured by Toki Sangyo Co., Ltd.]. Cone rotor: Standard cone rotor (1°34' x R24) Measurement temperature: 25°C Measurement range: M Rotation speed: 50 rpm

[0022] From the viewpoints of viscosity and light resistance, the mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') preferably contains a monofunctional monomer and a polyfunctional monomer. The monofunctional monomer is a compound having one functional group that undergoes a polymerization reaction when exposed to active energy rays, and the functional group has a carbon-carbon double bond. The polyfunctional monomer is a compound having two or more functional groups that undergo a polymerization reaction when exposed to active energy rays, and at least one of the functional groups has a carbon-carbon double bond.

[0023] Specific examples of the monofunctional monomer include the above-mentioned active energy ray-polymerizable compound (A), such as bis(vinylsulfone)tricyclo[5.2.1.0]decane, (1-naphthyl)methyl acrylate, 4-biphenylmethyl acrylate, 1,1-biphenyl-2-yl acrylate, and 6MDNTA. Specific examples of the active energy ray-polymerizable compound (A'), such as the above-mentioned o-phenoxyphenylethyl acrylate and m-phenoxybenzyl acrylate.

[0024] Specific examples of the polyfunctional monomer include the active energy ray-polymerizable compound (A), such as 4,4'-bisacryloxymethylbiphenyl, bis(4-methacryloylthiophenyl)sulfide, 1,1'-thiobis(4-ethenylthiobenzene), BINLA, DAOBINL, 16DVNDSH, and OGSOL EA-0200. Specific examples of the active energy ray-polymerizable compound (A'), such as dimethylol-tricyclodecane diacrylate, dimethylol-tricyclodecane dimethacrylate, and dipentaerythritol hexaacrylate, are listed above.

[0025] <Inorganic Particles (B)> The inorganic particles (B) will be described below: There are no particular limitations on the inorganic particles (B) as long as they are particles having a number average particle size of 5 to 50 nm and a refractive index of 2.2 to 2.5.

[0026] Inorganic particles (B) having a number-average particle diameter of 5 to 50 nm have excellent dispersion stability and can provide cured products with high light transmittance and refractive index. The number-average particle diameter of inorganic particles (B) is preferably 5 to 40 nm, more preferably 10 to 40 nm, and even more preferably 20 to 40 nm. In the present invention, the number-average particle diameter of inorganic particles (B) is the average primary particle diameter measured from 300 particles in a photograph (25k) taken with a transmission electron microscope (JEOL Ltd., JEM-F200). Here, the average primary particle diameter is the average particle diameter of all particles, where the diameter of a circle having an area equivalent to that of each particle in the photograph (circle-equivalent diameter) is taken as the particle diameter of that particle.

[0027] The refractive index of the inorganic particles (B) is 2.2 to 2.5, and preferably 2.3 to 2.5. If the refractive index is less than 2.2, the refractive index of the active energy ray-curable composition will be low, and if it exceeds 2.5, the light resistance will be poor. Literature values ​​were used for the refractive index of the inorganic particles (B).

[0028] 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 compounds, oxides (oxides of metal elements, oxides of nonmetal elements, and oxides containing metal elements and nonmetal elements) are preferred from the viewpoint of refractive index. The inorganic particles (B) may be used alone or in combination of two or more types.

[0029] As inorganic particles, from the viewpoint of refractive index, GaN, BaTiO ３ , ZnS, SrTiO ３ , FeTiO ３ , MnTiO ３ , PZT, PbTiO ３ , Nb ２ O ５ At least one type of particle selected from the group consisting of Nb is preferred, and Nb ２ O ５ or BaTiO ３ (barium titanate).

[0030] The shape of the inorganic particles (B) is not particularly limited, and may be any of spherical, hollow, porous, rod-like, plate-like, fibrous, amorphous, etc. Among them, spherical is preferred because it provides excellent dispersion stability and a cured product with high light transmittance and refractive index. The inorganic particles (B) are preferably crystalline. The crystal structure is not particularly limited, but monoclinic is preferred because it provides excellent dispersion stability and a cured product with high light transmittance and refractive index.

[0031] <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).

[0032] 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 (Omnirad 184), 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 phosphine oxides (C7) include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO), 2,4,6-trimethylbenzoylethylphenylphosphine oxide (Omnirad TPO-L), 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]octane-1,2-dione 2-(O-benzoyloxime) and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (Irgacure OXE02).

[0033] Among 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. One type of photopolymerization initiator (C) may be used alone, or two or more types may be used in combination.

[0034] The active energy ray-curable composition of the present invention can be diluted with an organic solvent (D) as necessary to the extent that the effects of the present invention are not impaired. Examples of the organic solvent (D) include alcohols (methanol, ethanol, isopropanol, butanol, 3-methoxybutanol, diacetone alcohol, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, 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 (diethylene glycol dimethyl ether, diethylene glycol diethyl 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, preferred are 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. The organic solvent (D) may be used alone or in combination of two or more.

[0035] The active energy ray-curable composition of the present invention can be diluted with a mold release agent (E) as needed, as long as the effects of the present invention are not impaired. Examples of the mold release agent (E) 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 Chemical Co., Ltd.). Examples of silicone leveling agents include BYK-333 (manufactured by BYK Japan K.K.), KP-423 (manufactured by Shin-Etsu Chemical Co., Ltd.), and Polyflow KL-401 (manufactured by Kyoeisha Co., Ltd.). The mold release agent (E) may be used alone or in combination of two or more types.

[0036] In addition to the above components, the active energy ray-curable composition of the present invention may contain other additives as needed within a range that does not impair the effects of the present invention. Examples of other additives include antioxidants, hindered amine light stabilizers, ultraviolet absorbers, antistatic agents, colorants, polymerization inhibitors, chain transfer agents, fillers, plasticizers, and thixotropy-imparting agents (thickeners).

[0037] The weight ratio of the mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') in the curable composition of the present invention is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and even more preferably 15 to 30% by weight, of the components excluding the organic solvent. If the weight ratio exceeds 50% by weight, the refractive index may decrease, and if it is less than 5% by weight, the imprintability may deteriorate.

[0038] The weight proportion of the inorganic particles (B) in the curable composition of the present invention is preferably 50 to 95% by weight, more preferably 60 to 90% by weight, and even more preferably 70 to 85% by weight, based on the components excluding the organic solvent. If the weight proportion exceeds 95% by weight, the imprintability may deteriorate, and if it is less than 50% by weight, the refractive index may decrease.

[0039] The weight ratio of the mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') is preferably 3 to 50% by weight, more preferably 3 to 30% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the active energy ray-polymerizable compound (A'), the inorganic particles (B), and the photopolymerization initiator (C). When the weight ratio is 3% by weight or more, the imprintability tends to be good, and when it is 50% by weight or less, the refractive index of the cured product tends to be good.

[0040] The weight proportion of the inorganic particles (B) is preferably 48.9 to 95.9% by weight, more preferably 68 to 95% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the active energy ray-polymerizable compound (A'), the inorganic particles (B), and the photopolymerization initiator (C). When the weight proportion is 48.9% by weight or more, the refractive index of the cured product tends to be good, and when it is 95.9% by weight or less, the imprintability tends to be good.

[0041] The weight proportion of the photopolymerization initiator (C) is preferably 0.1 to 10% by weight, more preferably 0.1 to 5% by weight, and even more preferably 0.1 to 3% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the active energy ray-polymerizable compound (A'), the inorganic particles (B), and the photopolymerization initiator (C).

[0042] When the active energy ray-curable composition contains the organic solvent (D), the weight proportion of the organic solvent (D) is preferably 0.001% by weight to 800% by weight, more preferably 0.5% by weight to 700% by weight, and even more preferably 1% by weight to 600% by weight, based on the total weight of the active energy ray-polymerizable compound (A), the active energy ray-polymerizable compound (A'), the inorganic particles (B), and the photopolymerization initiator (C).

[0043] When the active energy ray-curable composition contains the mold release agent (E), the weight proportion of the mold release agent (E) is preferably 0.01% by weight to 10% by weight based on the total weight of the active energy ray-polymerizable compound (A), the active energy ray-polymerizable compound (A'), the inorganic particles (B), and the photopolymerization initiator (C).

[0044] The weight proportion of the other additives in the active energy ray-curable composition is preferably 0.01% by weight to 10% by weight based on the total weight of the active energy ray-polymerizable compound (A), the active energy ray-polymerizable compound (A'), the inorganic particles (B), and the photopolymerization initiator (C).

[0045] When the active energy ray-curable composition contains the active energy ray-polymerizable compound (A'), the weight ratio of the active energy ray-polymerizable compound (A) to the active energy ray-polymerizable compound (A') [(A) / (A')] is preferably 0.3 to 100.

[0046] In the curable composition of the present invention, the weight ratio ((A) / (B)) of the active energy ray-polymerizable compound (A) to the inorganic particles (B) is preferably 0.05 to 1, more preferably 0.1 to 0.7.

[0047] When the active energy ray-curable composition contains the active energy ray-polymerizable compound (A'), the weight ratio of the total of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') to the inorganic particles (B), [((A)+(A')) / (B)], is preferably 0.05 to 1, and more preferably 0.1 to 0.7.

[0048] 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), and, if necessary, the active energy ray-polymerizable compound (A'), organic solvent (D), mold release agent (E), and the other additives described above 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 (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, and propylene glycol monomethyl ether acetate). Furthermore, to adjust the weight ratio of the organic solvent to a preferred amount, the organic solvent may be distilled off under reduced pressure.

[0049] The viscosity of the active energy ray-curable composition of the present invention at 25°C after heating at 100°C for 60 minutes is preferably 10,000 Pa·s or less, more preferably 0.1 to 7,000 Pa·s, and even more preferably 0.5 to 3,000 Pa·s, from the viewpoint of imprintability. The viscosity of the active energy ray-curable composition at 25°C after heating at 100°C for 60 minutes can be adjusted by adjusting the types and composition ratios of the components contained in the active energy ray-curable composition. The method for measuring the viscosity of the active energy ray-curable composition at 25°C after heating at 100°C for 60 minutes is as follows. By heating the active energy ray-curable composition at 100°C for 60 minutes, much of the organic solvent contained in the curable composition is distilled off, and therefore the viscosity measured under these conditions is often the viscosity after distillation of the organic solvent. Note that when an organic solvent with a high boiling point is used, or when a large amount of organic solvent is used, it is possible that not all of the organic solvent is distilled off under the above conditions.

[0050] <Method for measuring viscosity> The active energy ray-curable composition is heated at 100°C for 60 minutes, and then the temperature is controlled at 25°C for 30 minutes, and the viscosity (Pa s) is measured under the following conditions using a viscoelasticity measuring device ["MCR-302" manufactured by Anton Paar]. [Measurement conditions] Cone plate: CP-25-2 Measurement temperature: 25°C Shear rate: 1 / s

[0051] <Cured Product> The cured product of the present invention is obtained by curing the active energy ray-curable composition of the present invention. The cured product can be obtained, for example, by irradiating a coating film or a molded article made of the active energy ray-curable composition of the present invention with active energy rays to cure it. The wavelength of the active energy rays is not particularly limited as long as it can cure the curable composition, but is preferably 350 nm to 410 nm. A representative example of the active energy rays 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 curable 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.

[0052] 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, an LED, or the like. Among them, LEDs consume less power and generate less ozone than other light sources, have lower running costs, and have a lower environmental impact. 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.] or the like can be used.

[0053] 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 irradiation target can be irradiated with light by moving the irradiation target relative to the light source or by moving the light source relative to the irradiation target. In the case of a line type, the irradiation time can be easily adjusted, and therefore the cumulative exposure amount can be easily adjusted.

[0054] In the present invention, the cured product may be heated. Heating can further promote curing and reduce the linear expansion coefficient of the cured product. When heating, the heating temperature is preferably 90°C or higher.

[0055] The refractive index of the cured product of the present invention is preferably 1.60 or more, and more preferably 1.80 to 2.10. A refractive index of 1.60 or more tends to improve brightness when used as an optical lens, which is preferable. The refractive index may be 1.81 or more, 1.82 or more, 1.83 or more, or 1.84 or more.

[0056] A method for producing an optical component by curing the active energy ray-curable composition of the present invention will be described below. The method for producing an optical component is not particularly limited, but the component can be produced, for example, by the following method. That is, the curable composition of the present invention is coated onto a transparent substrate (such as a transparent plate or 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 it with active energy rays from the transparent substrate side, and then the coated film is released from the mold to obtain an optical component.

[0057] Examples of the transparent substrate include those made of glass or resin (methyl methacrylate (co)polymer, polyethylene terephthalate, polycarbonate, polytriacetyl cellulose, polycycloolefin, etc.).

[0058] The present specification discloses the following:

[0059] The present disclosure (1) is an active energy ray-curable composition comprising: an active energy ray-polymerizable compound (A) which is a monomer having a carbon-carbon double bond and a refractive index of 1.59 or more; inorganic particles (B); and a photopolymerization initiator (C); the active energy ray-curable composition may also comprise an active energy ray-polymerizable compound (A') which is a monomer having a carbon-carbon double bond and a refractive index of less than 1.59; the inorganic particles (B) are particles having a number average particle diameter of 5 to 50 nm and a refractive index of 2.2 to 2.5; and a mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') has a viscosity of 300 mPa s or less at 25°C.

[0060] The present disclosure (2) is a method for manufacturing the inorganic particles (B) comprising the steps of: ２ O ５ or BaTiO ３The active energy ray-curable composition according to the present disclosure (1),

[0061] The present disclosure (3) is the active energy ray-curable composition according to the present disclosure (1) or (2), in which the active energy ray-polymerizable compound (A) is a monomer including at least one skeleton selected from the group consisting of a naphthalene skeleton, a thiophene skeleton, a biphenyl skeleton, and a diphenyl sulfide skeleton.

[0062] The present disclosure (4) is the active energy ray-curable composition according to any one of the present disclosures (1) to (3), in which the mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') contains a monofunctional monomer and a polyfunctional monomer.

[0063] The present disclosure (5) is a cured product of the active energy ray-curable composition according to any one of the present disclosures (1) to (4).

[0064] 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.

[0065] <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 active energy ray-polymerizable compound (A), the active energy ray-polymerizable compound (A'), the inorganic particles (B), the photopolymerization initiator (C), the organic solvent (D), and the mold release agent (E) were charged into a glass container and stirred until uniform, thereby obtaining active energy ray-curable compositions of Examples 1 to 9 and Comparative Examples 1 to 3.

[0066]

[0067] The raw materials used in Table 1 are as follows. The refractive indexes of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') are values ​​measured using an Abbe refractometer (DR-M2: manufactured by Atago Co., Ltd.) under conditions of a wavelength of 589 nm (D-ray) and a measurement temperature of 25°C.

[0068] (A-1): (1-naphthyl)methyl acrylate [NMT-A: manufactured by Kyoeisha Chemical Co., Ltd., refractive index (25°C): 1.60] (A-2): 4-biphenylmethyl acrylate [KOMERATE H008: manufactured by Green Chemical Co., Ltd., refractive index (25°C): 1.60] (A-3): 1,1-biphenyl-2-yl acrylate [Viscoat 224: manufactured by Osaka Organic Chemical Co., Ltd., refractive index (25°C): 1.59] (A-4): dinaphthothiophene derivative [6MDNTA: manufactured by Sugai Chemical Industry Co., Ltd., refractive index (25°C): 1.71] (A-5): 4,4'-bisacryloxymethylbiphenyl [DABP: manufactured by JFE Chemical Co., Ltd., refractive index (25°C): 1.59] (A-6): Bis(4-methacryloylthiophenyl) sulfide [manufactured by Nacalai Tesque, Inc., refractive index (25°C): 1.66] (A-7): 1,1'-thiobis(4-ethenylthiobenzene) [manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., refractive index (25°C): 1.69] (A-8): Binaphthol derivative [BINLA: manufactured by Sugai Chemical Industry Co., Ltd., refractive index (25°C): 1.64] (A-9): Binaphthol derivative [DAOBINL: manufactured by Sugai Chemical Industry Co., Ltd., refractive index (25°C): 1.66] (A-10): Naphthothiol derivative [16DVNDSH: manufactured by Sugai Chemical Industry Co., Ltd., refractive index (25°C): 1.70] (A-11): Fluorene acrylate derivative [Oxol EA-0200: manufactured by Osaka Gas Chemicals Co., Ltd., refractive index (25 ° C): 1.62] (A'-1): o-phenoxyphenylethyl acrylate [A-LEN-10: manufactured by Shin-Nakamura Chemical Co., Ltd., refractive index (25 ° C): 1.58] (A'-2): m-phenoxybenzyl acrylate [POB-A: manufactured by Kyoeisha Chemical Co., Ltd., refractive index (25 ° C): 1.57] (A'-3): dimethylol-tricyclodecane diacrylate [Light Acrylate DCP-A: manufactured by Kyoeisha Co., Ltd., refractive index (25 ° C): 1.50] (A'-4): dimethylol-tricyclodecane dimethacrylate [DCP: manufactured by Shin-Nakamura Chemical Co., Ltd., refractive index (25 ° C): 1.50] (A'-5): Dipentaerythritol hexaacrylate [Neomer DA-600: manufactured by Sanyo Chemical Industries, Ltd., refractive index (25°C): 1.47]

[0069] (B-1): Barium titanate (BaTiO３ (B-1): a solution of titanium dioxide (TiO) particles (number average particle diameter: 40 nm, refractive index: 2.4) dispersed in propylene glycol monomethyl ether [product name "9714BT", solid content: 15% by weight, manufactured by Tokushiki Co., Ltd.] ２ ) particles [product name "TTO-51(C)", number average particle diameter 20 nm, refractive index 2.7, manufactured by Ishihara Sangyo Kaisha, Ltd.] (B-3): niobium oxide (Nb ２ O ５ ) Particles [product name "Nb-G6000", number average particle diameter 20 nm, refractive index 2.3, manufactured by Taki Chemical Co., Ltd.]

[0070] (C-1): 2,4,6-trimethylbenzoyldiphenylphosphine oxide [trade name "Omnirad TPO", manufactured by IGM Resins B.V.] (C-2): 2,4,6-trimethylbenzoylethylphenylphosphine oxide [trade name "Omnirad TPO-L", manufactured by IGM Resins B.V.] (C-3): 1-hydroxycyclohexylphenyl ketone [trade name "Omnirad 184", manufactured by IGM Resins B.V.]

[0071] (D-1): 2-methoxy-1-methylethyl acetate [PGMEA: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.]

[0072] (E-1): Fluorine additive [F-444: manufactured by DIC Corporation]

[0073] The active energy ray-curable compositions prepared in each of the Examples and Comparative Examples were evaluated for viscosity, refractive index, light resistance, and imprintability by the following methods. The results are shown in Table 1.

[0074] <Measurement of Viscosity> (1) Viscosity of Mixture of Active Energy Ray-Polymerizable Compound (A) and Active Energy Ray-Polymerizable Compound (A') The mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') used in Examples 1 to 9 and Comparative Examples 1 to 3 was temperature-controlled 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.]. [Measurement conditions] Cone rotor: Standard cone rotor (1°34' x R24) Measurement temperature: 25°C Measurement range: M Rotation speed: 50 rpm (2) Viscosity of active energy ray-curable composition at 25°C after heating at 100°C for 60 minutes The active energy ray-curable composition was heated at 100°C for 60 minutes, and the mixture obtained was kept at 25°C for 30 minutes, and the viscosity (Pa s) was measured using the measurement device and under the measurement conditions described in this specification.

[0075] <Preparation of Cured Product for Evaluating Refractive Index and Light Fastness> 1 g of the active energy ray-curable composition was dropped onto a 10 cm square glass substrate [Eagle XG, manufactured by Corning Co., Ltd.] and applied by spin coating at 3000 rpm for 30 seconds. After drying at 100°C for 3 minutes, the composition was irradiated with ultraviolet light at 1000 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 having a film thickness of 100 nm for evaluation of refractive index and light resistance.

[0076] <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.

[0077] <Light resistance> The cured product prepared as described above was subjected to a light resistance test (illuminance: 25 mW / cm) using an Eye Super UV Tester (SUV-W131, manufactured by Iwasaki Electric Co., Ltd.). ２The degree of coloration of the cured product was visually observed, and the change in refractive index (absolute value of the difference in refractive index before and after the test) was measured and evaluated according to the following criteria: ⊚: No coloration, change in refractive index is less than 0.1 ◯: No coloration, change in refractive index is 0.1 or more but less than 0.2 ×: Coloration or change in refractive index is 0.2 or more

[0078] <Imprintability> (1) 1 g of the active energy ray-curable composition was dropped onto a 10 cm square glass substrate [Eagle XG, manufactured by Corning Corporation] and coated by spin coating at 500 rpm for 30 seconds, followed by drying at 100°C for 3 minutes to obtain a laminate of the glass substrate and coating film. (2) The laminate obtained in (1) was attached to a mold (DTM-3-1, manufactured by Kyodo International Co., Ltd.) so that the mold and the coating film were in contact, and a roller was rolled from above to push out air. UV light was irradiated from the glass substrate side using an ultraviolet irradiation device [model number "VPS / I600", manufactured by Fusion UV Systems Co., Ltd.] at 1000 mJ / cm. ２ The coating was cured by irradiating the coating. (3) The mold was removed from the cured product obtained in (2), and the surface of the cured product was observed under a scanning electron microscope (SEM) and evaluated according to the following criteria: ⊚: 80% or more (area ratio) of the mold irregularities were transferred. ◯: 30% or more but less than 80% (area ratio) of the mold irregularities were transferred. ×: Only less than 30% (area ratio) of the mold irregularities were transferred.

[0079] As can be seen from the results in Table 1, Comparative Examples 1 and 2, which do not contain the active energy ray-polymerizable compound (A), exhibit poor imprintability. Furthermore, the refractive index of the cured product is also lower than that of the Examples. Furthermore, Comparative Example 3, which uses an active energy ray-curable composition containing titanium oxide as inorganic particles (B) with a refractive index of 2.7, exhibits poor light resistance. In contrast, each Example produced a cured product that exhibited good results in all categories.

[0080] 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 for optical lens, coating material for decorative film, coating material for optical fiber, hard coat film, antireflection film, etc.).

[0081] The cured product prepared from the active energy ray-curable composition of the present invention has a high refractive index and is therefore useful as an optical part, specifically, as an optical part such as a plastic lens (such as 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 a multilayer printed wiring board, or a photosensitive optical waveguide.

Claims

1. An active energy ray-curable composition comprising: an active energy ray-polymerizable compound (A) which is a monomer having a carbon-carbon double bond and a refractive index of 1.59 or more; inorganic particles (B); and a photopolymerization initiator (C); and optionally comprising an active energy ray-polymerizable compound (A') which is a monomer having a carbon-carbon double bond and a refractive index of less than 1.59; the inorganic particles (B) have a number average particle size of 5 to 50 nm and a refractive index of 2.2 to 2.5; and the viscosity of a mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') at 25°C is 300 mPa s or less.

2. The inorganic particles (B) are Nb ２ O ５ or BaTiO ３ The active energy ray-curable composition according to claim 1, wherein 3. The active energy ray-curable composition according to claim 1, wherein the active energy ray-polymerizable compound (A) is a monomer containing at least one skeleton selected from the group consisting of a naphthalene skeleton, a thiophene skeleton, a biphenyl skeleton, and a diphenyl sulfide skeleton.

4. The active energy ray-curable composition according to claim 1, wherein the mixture of the active energy ray-polymerizable compound (A) and the active energy ray-polymerizable compound (A') contains a monofunctional monomer and a polyfunctional monomer.

5. A cured product of the active energy ray-curable composition according to any one of claims 1 to 4.

Images