Curable composition and cured product obtained by curing the same

Abstract

To provide, for example, a curable composition that is useful as an optical material, and a cured product formed by curing the same.SOLUTION: According to one embodiment, there is provided a curable composition containing 30 to 75 pts.mass of metal oxide nanoparticles (A), 5 to 30 pts.mass of an aromatic mono(meth)acrylate (B), and 5 to 30 pts.mass of a polyfunctional (meth)acrylate (C) having a functionality of 3 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition and a cured product obtained by curing the same. [Background technology]

[0002] Curable compositions that can be cured into any shape have traditionally been used in a wide range of industrial fields, including electrical and electronic equipment, office automation equipment, heavy electrical machinery, precision machinery, and automotive. Resin materials, in particular, are lightweight, highly tough, and easily processable, and have been widely used in various optical components, particularly lenses, in recent years. Furthermore, optical devices such as cameras mounted on mobile products, such as mobile phones, smartphones, tablet devices, and mobile computers, have become increasingly smaller, lighter, and more powerful in recent years. Accordingly, there has been a growing demand for smaller, lighter, and thinner lenses for use in these optical devices.

[0003] When a cured product obtained by curing a curable composition is used in an optical component, various properties are required depending on the application. For example, when the cured product is used in an optical lens, in addition to the desired refractive index and Abbe number, heat resistance, transparency, low water absorption, chemical resistance, low birefringence, moisture resistance, and the like may be required depending on the application of the optical lens. The curable composition may also be required to have a viscosity suitable for molding. Extensive research has been conducted to develop curable compositions with these excellent properties. Due to the recent technological advances described above, there is a particular demand for curable compositions capable of producing optical components with high refractive indexes. For example, in the case of optical lenses, a high refractive index allows lens elements with the same refractive index to be realized with a surface with a smaller curvature, thereby reducing the amount of aberration generated by this surface. This results in a reduction in the number of lenses, a reduction in the lens's decentering sensitivity, and a reduction in lens thickness and weight. Additionally, curable compositions with various desirable properties have been developed depending on the application, and desired properties have been achieved by adding additives such as nanoparticles (e.g., Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6022094 [Patent Document 2] Japanese Patent Application Publication No. 2023-180590 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-191931 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a curable composition useful as, for example, an optical material, and a cured product obtained by curing the same. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that a curable composition having a specific formulation has properties particularly suitable for optical materials. [1] 30 to 75 parts by mass of metal oxide nanoparticles (A); 5 to 30 parts by mass of an aromatic mono(meth)acrylate (B); 5 to 30 parts by mass of a polyfunctional (meth)acrylate (C) having 3 or more functional groups; (Here, the value of each part by mass is a value when the total mass of (A), (B) and (C) is 100 parts by mass.) [2] The curable composition according to [1], wherein the polyfunctional (meth)acrylate (C) is represented by the following general formula (1), (2), or (3): [ka] [In formulas (1), (2) and (3), Each X is independently selected from the group consisting of a single bond, an alkylene group, -O-, -S-, -N-, and combinations thereof; R is a group represented by the following formula (I): [ka] (each R1 is independently a hydrogen atom or a methyl group; * is the bonding site to X). [3] The curable composition according to [1] or [2], wherein the metal oxide nanoparticles (A) contain a metal oxide selected from the group consisting of zirconium oxide and titanium oxide. [3-1] The curable composition according to any one of [1] to [3], wherein the metal oxide nanoparticles (A) have an average particle size of 1 to 100 nm. [4] The curable composition according to any one of [1] to [3-1], wherein the aromatic mono(meth)acrylate (B) is represented by the following general formula (4): [ka] [In formula (4), Each Z is independently selected from the group consisting of a single bond, an alkylene group, -O-, -S-, -N-, and combinations thereof; Y is a group containing an aromatic ring; R2 is a hydrogen atom or a methyl group. [4-1] The curable composition according to any one of [1] to [4], wherein the polyfunctional (meth)acrylate (C) is selected from the group consisting of glycerin tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and trimethylolpropane tri(meth)acrylate. [5] The curable composition according to any one of [1] to [4-1], further comprising a polymerization initiator (D). [6] The curable composition according to any one of [1] to [5], which has a viscosity at 23°C of 30,000 mPa·s or less. [7] The curable composition according to any one of [1] to [6], which when cured has a refractive index of 1.650 or more at 25°C and 588 nm. [8] The curable composition according to any one of [1] to [7], which has a glass transition temperature (Tg) of 150° C. or higher when cured. [8-1] The curable composition according to any one of [1] to [8], which has an Abbe number (νd) of 25 or more when cured. [8-2] The curable composition according to any one of [1] to [8-1], which has a haze of 0 to 1.5%. [9] A cured product obtained by curing the curable composition according to any one of [1] to [8-2].

[10] The cured product according to [9], which is an optical component.

[11] The cured product according to

[10] , wherein the optical component is an optical lens. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a curable composition useful as, for example, an optical material, and a cured product obtained by curing the same. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail. According to one embodiment, the curable composition of the present invention contains 30 to 75 parts by mass of metal oxide nanoparticles (A), 5 to 30 parts by mass of an aromatic mono(meth)acrylate (B), and 5 to 30 parts by mass of a polyfunctional (meth)acrylate (C) having a functionality of 3 or more, where the value of each part by mass is based on 100 parts by mass of the total mass of (A), (B), and (C).

[0009] The present inventors have discovered that curable compositions having the above-described compositions and cured products thereof have physical properties particularly favorable for optical materials. In particular, when a polyfunctional (meth)acrylate (C) having three or more functional groups is incorporated, it is possible to obtain compositions and cured products thereof having viscosity, refractive index, Abbe number, glass transition temperature (Tg), haze, and other properties within suitable ranges compared to compositions not incorporating the polyfunctional (meth)acrylate (C) or compositions incorporating a (meth)acrylate having two or less functional groups. Generally, a high refractive index of an optical material allows a lens element having the same refractive index to be realized with a surface having a smaller curvature, thereby reducing the amount of aberration generated by this surface. This results in a reduction in the number of lenses, a reduction in the lens decentering sensitivity, and a reduction in lens thickness and weight. Furthermore, the composition having an appropriate viscosity and glass transition temperature has excellent moldability, enabling the production of small, complexly shaped components. Furthermore, cured products obtained by curing the curable compositions according to the present embodiment tend to have a higher Abbe number relative to the refractive index (i.e., when compared at the same refractive index). This has the advantage of reducing chromatic aberration. Having a haze value in an appropriate range also has the advantage of exhibiting high transparency. Thus, it can be said that the curable composition according to the embodiment has a good balance of properties that are favorable for optical materials.

[0010] The reason why a composition having the above-described composition, particularly a composition containing a polyfunctional (meth)acrylate having three or more functional groups, has the above-described preferable properties for optical materials is unclear, but it is presumed that the improved crosslink density results in higher heat resistance.

[0011] Hereinafter, each component, production method, physical properties, applications, etc. of the curable composition according to the embodiment will be described in detail. [1] Metal oxide nanoparticles (A) The metal oxide nanoparticles (A) may have an average particle size of, for example, 1 to 100 nm, preferably 1 to 50 nm, and more preferably 5 to 20 nm. The type of metal oxide is not particularly limited, but examples include silicon oxide, zirconium oxide, titanium oxide, zinc oxide, antimony pentoxide, tin oxide, aluminum oxide, indium oxide, indium tin oxide, ferric oxide, cerium oxide, yttrium oxide, manganese oxide, holmium oxide, copper oxide, bismuth oxide, cobalt oxide, tricobalt tetroxide, triiron tetroxide, magnesium oxide, lanthanum oxide, praseodymium oxide, neodymium oxide, samarium oxide, eurobium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, scandium oxide, tantalum pentoxide, niobium pentoxide, iridium oxide, rhodium oxide, and ruthenium oxide. Of these, zirconium oxide and titanium oxide are preferred, and zirconium oxide is more preferred.The metal oxide nanoparticles contained in the curable composition may be of one type or two or more types.

[0012] The metal oxide nanoparticles (A) may be surface-treated. A suitable surface treatment agent for the nanoparticles is a compound having a substituent capable of bonding to the surface of the nanoparticles and a substituent highly compatible with other components in the curable composition (e.g., aromatic mono(meth)acrylate (B), polyfunctional (meth)acrylate (C), etc.). Examples of surface treatment agents that can be used include silane compounds, alcohols, amines, carboxylic acids, sulfonic acids, phosphonic acids, and phosphoric acids.

[0013] The average particle diameter of the metal oxide nanoparticles (A) can be measured by observing them with an electron microscope. For example, they can be observed under magnification using a transmission electron microscope (TEM), field emission transmission electron microscope (FE-TEM), field emission scanning electron microscope (FE-SEM), etc., and the diameters of 50 randomly selected particles are measured and the average value calculated. If the particles are not spherical, the average value of the major and minor axes is considered to be the diameter of the particle.

[0014] The metal oxide nanoparticles (A) are contained in the curable composition in an amount of 30 to 75 parts by mass, preferably 50 to 75 parts by mass or 55 to 75 parts by mass, and more preferably 65 to 75 parts by mass, based on 100 parts by mass of the total mass of the components (A), (B), and (C). By containing the metal oxide nanoparticles (A) in such an amount, a high refractive index and low cure shrinkage are expected.

[0015] [2] Aromatic mono(meth)acrylate (B) The curable composition according to the embodiment contains an aromatic mono(meth)acrylate (B). The aromatic mono(meth)acrylate (B) is not particularly limited as long as it is a mono(meth)acrylate having an aromatic ring, but for example, has a structure represented by the following general formula (4). [ka] [In formula (4), Each Z is independently selected from the group consisting of a single bond, an alkylene group, -O-, -S-, -N-, and combinations thereof; Y is a group containing an aromatic ring; R2 is a hydrogen atom or a methyl group.

[0016] In general formula (4), Z is more preferably a single bond, an alkylene group, -O-, or a combination thereof, and particularly preferably an alkylene group having 1 to 5 carbon atoms, -O-, or a combination thereof. Y is not particularly limited as long as it contains an aromatic ring (e.g., a benzene ring, a naphthalene ring, a biphenyl ring, a fluorene ring, an anthracene ring, a stilbene ring, a dibenzothiophene ring, or a carbazole ring), but is preferably a group containing a phenyl group, a naphthyl group, or a biphenyl group, and more preferably Y is a phenyl group, a naphthyl group, or a biphenyl group. Each group in Z and Y may further have a substituent, and examples of such a substituent include a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group, an acyl group, an alkoxy group, a carboxy group, a nitro group, and an amino group.

[0017] More specifically, examples of the aromatic mono(meth)acrylate (B) include naphthalene-1-ylmethyl acrylate, ethoxylated-o-phenylphenol acrylate, phenyl(meth)acrylate, benzyl(meth)acrylate, phenoxybenzyl(meth)acrylate, biphenyl(meth)acrylate, phenoxyethyl(meth)acrylate, phenylphenoxymethyl(meth)acrylate, phenylphenoxyethyl(meth)acrylate, 2-phenyl-2'-(β-(meth)acryloyloxymethoxyphenyl)propane, 2-phenyl-2'-(β-(meth)acryloyloxyethoxyphenyl)propane, 2-phenoxy-2'-hydroxypropyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, and 2-(meth)acryloyloxy-2'-hydroxypropyl phthalate. Among these, naphthalene-1-ylmethyl acrylate and ethoxylated o-phenylphenol acrylate are more preferred. The aromatic mono(meth)acrylate (B) contained in the curable composition may be one type or two or more types.

[0018] The aromatic mono(meth)acrylate (B) is contained in the curable composition in an amount of 5 to 30 parts by mass, more preferably 10 to 20 parts by mass, and particularly preferably 10 to 15.5 parts by mass, based on 100 parts by mass of the total mass of the components (A), (B), and (C). By containing the aromatic mono(meth)acrylate (B) in such an amount, a high refractive index and a low viscosity are expected.

[0019] [3] Polyfunctional (meth)acrylate (C) The curable composition according to the embodiment contains a polyfunctional (meth)acrylate (C) having three or more functional groups. The polyfunctional (meth)acrylate (C) having three or more functional groups refers to a compound having three or more (meth)acryloyl groups in one molecule. The number of functional groups is preferably 3 to 6, more preferably 3 to 5, and particularly preferably 3 or 4. The polyfunctional (meth)acrylate (C) is not particularly limited as long as it has three or more functional groups, but may have, for example, a structure represented by the following general formula (1), (2), or (3). [ka] [In formulas (1), (2) and (3), Each X is independently selected from the group consisting of a single bond, an alkylene group, -O-, -S-, -N-, and combinations thereof; R is a group represented by the following formula (I): [ka] (each R1 is independently a hydrogen atom or a methyl group; * is the bonding site to X).

[0020] In general formulas (1) to (3), X is more preferably a single bond, an alkylene group, -O-, or a combination thereof, even more preferably an alkylene group having 1 to 5 carbon atoms, -O-, or a combination thereof, and particularly preferably an alkylene group having 1 to 5 carbon atoms. X may further have a substituent, and examples of such a substituent include a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group, an acyl group, an alkoxy group, a carboxy group, a nitro group, and an amino group.

[0021] More specifically, examples of the polyfunctional (meth)acrylate (C) having three or more functional groups include glycerin tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc. Among these, glycerin triacrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate are particularly preferred. The polyfunctional (meth)acrylate (C) contained in the curable composition may be one type or two or more types.

[0022] The polyfunctional (meth)acrylate (C) is contained in the curable composition in an amount of 5 to 30 parts by mass, more preferably 10 to 20 parts by mass, based on 100 parts by mass of the total mass of the components (A), (B), and (C). By containing the polyfunctional (meth)acrylate (C) in such an amount, improved heat resistance is expected.

[0023] [4] Additives The curable composition according to the present embodiment may further contain additives to achieve desired properties. Any additive that can be contained in a resin composition can be used as the additive, including, for example, polymerization initiators, curing accelerators, compounding agents, catalyst deactivators, heat stabilizers, plasticizers, fillers, UV absorbers, rust inhibitors, dispersants, antifoaming agents, leveling agents, flame retardants, lubricants, dyes, pigments, bluing agents, nucleating agents, and clarifying agents. Such additives are preferably contained in a total amount of 0.1 to 10% by mass, more preferably 0.1 to 2% by mass, based on the curable composition. By ensuring that the additive content is within the above range, the effects of the components (A) to (C) described above can be exerted without being impaired.

[0024] The curable composition preferably contains a polymerization initiator. Examples of the polymerization initiator include photopolymerization initiators and thermal polymerization initiators, and they can be appropriately selected depending on the method for curing the composition. The polymerization initiator is not particularly limited as long as it generates active radical species upon irradiation with actinic rays (ultraviolet rays, visible light, etc.) or heating, and examples thereof include 2,2-methoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Examples of peroxyalkylene oxides include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, tert-butyl peroxylaurate, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl carbonate, tert-butyl peroxyacetate, diisopropylbenzene hydroperoxide, and tert-butylperoxy-2-ethylhexyl monocarbonate.

[0025] These polymerization initiators may be used alone or in combination of two or more. The amount of these polymerization initiators added is preferably in the range of 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the curable composition.

[0026] The curable composition preferably contains a polymerization inhibitor (stabilizer). Examples of polymerization inhibitors include free radical polymerization inhibitors. N-oxo compounds generally have a high stabilizing effect. Among them, N-nitrosophenylhydroxylamine salt derivatives are preferred due to their high stabilizing effect, and N-nitrosophenylhydroxylamine aluminum salt, which has relatively high solubility in many monomers, is particularly preferred. These polymerization inhibitors can achieve significant stabilizing effects even when added in small amounts, such as 0.001 parts by mass per 100 parts by mass of the total monomer components. Addition of large amounts slightly reduces the stability of the composition and can cause deterioration in color tone. Therefore, the amount added is preferably in the range of 0.001 to 1 part by mass, and more preferably 0.002 to 0.5 parts by mass, per 100 parts by mass of the total monomer components. However, addition in excess of this range does not significantly reduce the stability of the curable composition. Specific examples of the polymerization inhibitor include hydroquinones such as hydroquinone, methylhydroquinone, t-butylhydroquinone, and hydroquinone monomethyl ether; nitroso compounds such as p-nitrosophenol, nitrosobenzene, N-nitrosodiphenylamine, isononyl nitrite, N-nitrosocyclohexylhydroxylamine, N-nitrosophenylhydroxylamine, N,N'-dinitrosophenylenediamine, or salts thereof; nitrone compounds such as α-phenyl-Nt-butylnitrone and α-naphthyl-Nt-butylnitrone; and nitroxide compounds such as 2,2,6,6-tetramethyl-1-piperidinoxide (TEMPO) and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinoxide.

[0027] The curable composition may also contain a radically polymerizable compound other than the above-mentioned components (B) and (C), and it is particularly preferred that the curable composition contains a (meth)acrylate compound other than the components (B) and (C). The curable composition according to the embodiment can be produced by a method commonly used in the art. For example, the curable composition can be obtained by uniformly mixing the components at room temperature or under heating according to a conventional method. The mixed composition may be subjected to steps such as filtration, degassing, and solvent distillation, as necessary.

[0028] [5] Physical properties of curable compositions (viscosity) The curable composition according to the embodiment has a viscosity at 23°C of 30,000 mPa·s or less (e.g., 100 to 30,000 mPa·s), more preferably 20,000 mPa·s or less (e.g., 100 to 20,000 mPa·s), and particularly preferably 10,000 mPa·s or less (e.g., 100 to 10,000 mPa·s). Such a viscosity at 23°C provides excellent handleability at room temperature and allows successful molding into a desired shape. The viscosity can be measured by the method described in the Examples below.

[0029] (Refractive index; nd) The refractive index (nd) of the cured resin obtained by curing the curable composition according to the embodiment is preferably 1.650 or more (e.g., 1.650 to 1.700), more preferably 1.660 or more (e.g., 1.660 to 1.700), and particularly preferably 1.670 or more (e.g., 1.670 to 1.700) or 1.680 or more (e.g., 1.680 to 1.700). The curable composition according to the embodiment can achieve a high refractive index while exhibiting other desirable effects (e.g., moldability). Here, the refractive index is measured at 25°C and at a wavelength of 588 nm in accordance with JIS B 7071-2:2018. More specifically, the refractive index can be measured by the method described in the Examples section below.

[0030] (Abbe number; νd) The Abbe number of the cured resin product obtained by curing the curable composition according to the embodiment is preferably at least 25, more preferably at least 30, and particularly preferably at least 35. The Abbe number can be measured by the method described in the examples below.

[0031] (glass transition temperature; Tg) The glass transition temperature (Tg) of the cured resin obtained by curing the curable composition according to the embodiment is preferably 150°C or higher (e.g., 150 to 300°C), more preferably 200°C or higher (e.g., 200 to 300°C), and particularly preferably higher than 220°C (e.g., higher than 220°C and 300°C or lower). When the glass transition temperature is in this range, both heat resistance and moldability can be achieved. The glass transition temperature can be measured by the method described in the examples below.

[0032] (Hayes) The haze of the curable composition according to the embodiment is preferably 0 to 1.5%, more preferably 0 to 1%, and particularly preferably 0 to 0.7% or 0 to 0.5%. With the haze in this range, high transparency can be expected. The haze can be measured by the method described in the Examples below.

[0033] [6] Cured product A cured product can be obtained by curing the curable composition described above by a method commonly used in this field. Thus, according to one embodiment, a cured product is provided by curing the curable composition described above. Here, the term "cured product" includes not only resin cured products of various shapes obtained by simply curing the curable composition, but also molded articles obtained by molding the curable composition into specific shapes. The curing method is not particularly limited, and can be performed by various known methods. For example, curing can be achieved by irradiation with active energy rays, heating, etc. Examples of active energy rays include ultraviolet rays, visible light, electron beams, ion beams, and X-rays. The light source used is not particularly limited as long as it generates the active energy rays, but specific examples include high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, high-power metal halide lamps, xenon lamps, and light-emitting diodes (UV LEDs).

[0034] The curable composition according to the embodiment can be irradiated with active energy rays and / or heat-treated, and then annealed to remove internal strain. The heating temperature and heating time can be appropriately set depending on the desired degree of curing, but the heating temperature is preferably 100 to 200°C, and the heating time is preferably 30 minutes to 10 hours, more preferably 30 minutes to 3 hours.

[0035] When a molded article having a specific shape is obtained, the shape is not particularly limited, and for example, it can be molded into a lens shape, a sheet shape, or the like. The molding method is also not particularly limited, and examples thereof include a method in which the curable composition is injected into a mold having a desired shape and then cured by the above-mentioned method. Alternatively, the desired shape may be formed by extrusion molding or the like.

[0036] As described above, the curable composition according to the embodiment can be used in various applications by molding it into a desired shape. In particular, the curable composition according to the embodiment and its cured product have the properties described above, and therefore can be suitably used, for example, as an optical component. Optical components include, but are not limited to, optical disks, transparent conductive substrates, optical cards, sheets, films, optical fibers, lenses, prisms, optical films, substrates, optical filters, hard coat films, and the like. In a preferred embodiment, the curable composition is used as an optical lens.

[0037] The optical lens produced using the curable composition according to the embodiment has a high refractive index and is excellent in moldability, heat resistance, etc., and therefore, when used as an optical lens, it can be used in fields where expensive high refractive index glass lenses have traditionally been used, such as telescopes, binoculars, and television projectors, and is extremely useful. The optical lens can be molded by any method, such as mold molding, cutting, polishing, laser processing, electrical discharge machining, and etching. Among these, mold molding is more preferred in terms of production costs. The shape of the optical lens is not particularly limited. [Example]

[0038] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. The raw materials used in the examples are as follows. (A) Component 1: Trade name "Zircostar ZP-153", manufactured by Nippon Shokubai Co., Ltd., nano zirconium oxide methyl ethyl ketone dispersion (solid content 70%), average particle size 11 nm (B) Component 1: Trade name "Light Acrylate NMT-A", Kyoeisha Chemical Co., Ltd., naphthalene-1-ylmethyl acrylate [ka] (B) Component 2: Product name "NK Ester A-LEN-10", Shin-Nakamura Chemical Co., Ltd., ethoxylated o-phenylphenol acrylate [ka]

[0039] (C) Component 1: Product name "Aronix M-930", Toagosei Co., Ltd., glycerin triacrylate [ka] (C) Component 2: Trade name "NK Ester A-TMMT", Shin-Nakamura Chemical Co., Ltd., pentaerythritol tetraacrylate [ka] (D) Component 1: Trade name "Omnirad TPO H", IGM Resins BV, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (D) Component 2: Trade name "Perbutyl Z" NOF Corporation, tert-butyl peroxybenzoate Aliphatic mono(meth)acrylate: Product name "Viscoat #200", Osaka Organic Chemical Industry Co., Ltd., cyclic trimethylolpropane formal acrylate Bifunctional mono(meth)acrylate 1: Product name "NK Ester ABE-300", Shin-Nakamura Chemical Co., Ltd., ethoxylated bisphenol A diacrylate Bifunctional mono(meth)acrylate 2: Product name "NK Ester A-BPE-4", Shin-Nakamura Chemical Co., Ltd., ethoxylated bisphenol A diacrylate Bifunctional mono(meth)acrylate 3: Trade name "Light Acrylate DCP-A", Kyoeisha Chemical Co., Ltd., dimethylol-tricyclodecane diacrylate

[0040] <Examples and Comparative Examples> A curable composition was obtained by mixing and stirring the components shown in Tables 1 and 2 in a predetermined ratio until uniform, and then evaporating and distilling off the solvent. The amount of each component in Tables 1 and 2 is expressed in parts by mass. The obtained curable composition was sandwiched between two opposing glass plates with a 0.25 mm thick spacer in between, and irradiated with 50 mW / cm using a UV-LED light irradiator 405 (product name "UV Irradiator 405 nm LED" manufactured by CCS Inc., peak wavelength 405 nm). 2 The resin was cured by irradiating it with light for 10 minutes, after which the glass plate was removed to obtain a cured resin. In Comparative Example 2-4, the curable composition was sandwiched between two opposing glass plates with a 0.25 mm thick spacer in between, and cured by heating under the following conditions: the temperature was raised from 30° C. to 140° C. over one hour, maintained at 140° C. for one hour, and then cooled from 140° C. to 30° C. over one hour. The glass plates were then removed to obtain a cured resin product.

[0041] The curable compositions and cured resin products of the examples and comparative examples were measured for various physical properties as follows. (1) Viscosity The viscosity of the curable composition was measured at 23°C or 50°C using an EMS viscometer (product name "EMS-1000S", manufactured by Kyoto Electronics Manufacturing Co., Ltd.). (2) Refractive index, Abbe number The refractive index (nd) and Abbe number (νd) of the cured resin were measured using a refractometer (trade name "KPR-3000", manufactured by Shimadzu Corporation) at a temperature of 25°C. (3) Glass transition temperature (Tg) The glass transition temperature of the cured resin was determined by measuring the peak temperature of tanδ using a viscoelasticity measuring device (trade name "DMA7100" manufactured by Hitachi High-Tech Science Corporation) at a temperature increase rate of 2°C per minute and a frequency of 10 Hz. For resins where Tg was not observed at 220°C, the Tg was considered to be 220°C or higher. (4) Hayes The haze of the 0.25 mm thick cured resin product was measured using a spectrophotometer (product name "CM-5", manufactured by Konica Minolta, Inc.).

[0042] The measurement results are shown in Tables 1 and 2 below. [Table 1] [Table 2]

[0043] From Tables 1 and 2, it can be seen that the curable compositions of the Examples have a high refractive index, making them suitable for optical materials, and furthermore, have a glass transition temperature (Tg) within a preferred range, making them excellent in moldability and heat resistance. Furthermore, they also have properties suitable for optical materials in terms of Abbe number and haze, and can be seen to have a well-balanced range of desirable properties for optical materials. The viscosity of the composition of Comparative Example 1 at 23°C was too high, making it impossible to rotate the probe of the EMS viscometer and therefore impossible to measure the viscosity at 23°C.

[0044] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

Claims

1. 30 to 75 parts by mass of metal oxide nanoparticles (A); 5 to 30 parts by mass of an aromatic mono(meth)acrylate (B); 5 to 30 parts by mass of a polyfunctional (meth)acrylate (C) having a functionality of 3 or more; (Here, the value of each part by mass is a value when the total mass of (A), (B), and (C) is 100 parts by mass.)

2. The curable composition according to claim 1, wherein the polyfunctional (meth)acrylate (C) is represented by the following general formula (1), (2), or (3): 【Chemistry 1】 [In formulas (1), (2) and (3), Each X is independently selected from the group consisting of a single bond, an alkylene group, —O—, —S—, —N—, and combinations thereof; R is a group represented by the following formula (I): 【Chemistry 2】 (R １ are each independently a hydrogen atom or a methyl group; * is the bonding site to X).

3. 2. The curable composition of claim 1, wherein the metal oxide nanoparticles (A) comprise a metal oxide selected from the group consisting of zirconium oxide and titanium oxide.

4. The curable composition according to claim 1, wherein the aromatic mono(meth)acrylate (B) is represented by the following general formula (4): 【Transformation 3】 [In formula (4), Each Z is independently selected from the group consisting of a single bond, an alkylene group, —O—, —S—, —N—, and combinations thereof; Y is a group containing an aromatic ring; R ２ is a hydrogen atom or a methyl group.

5. The curable composition according to claim 1 , further comprising a polymerization initiator (D).

6. The curable composition according to claim 1, having a viscosity at 23°C of 30,000 mPa·s or less.

7. 2. The curable composition according to claim 1, which, when cured, has a refractive index of 1.650 or greater at 25°C and 588 nm.

8. The curable composition according to claim 1, which when cured has a glass transition temperature (Tg) of 150°C or higher.

9. A cured product obtained by curing the curable composition according to any one of claims 1 to 8.

10. The cured product according to claim 9 , which is an optical component.

11. The cured product according to claim 10 , wherein the optical component is an optical lens.

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