High refractive index curable composition and high refractive index cured product

Abstract

To provide a high refractive index curable composition capable of forming a high refractive index cured product that combines a high refractive index, a high glass transition temperature, and excellent transparency.SOLUTION: A high refractive index curable composition contains a polyfunctional (meth)acrylate compound (A) represented by the general formula (1) in the figure, a monofunctional (meth)acrylate compound (B) having a naphthalene skeleton, inorganic nanoparticles, and a polymerization initiator.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a high refractive index curable composition and a high refractive index cured product. [Background technology]

[0002] BACKGROUND ART Coatings using materials having high refractive indexes and resin compositions for high refractive index layers are known for solar cells, optical elements such as lenses, and optical components such as coating films.

[0003] To date, composite coatings have been reported that include a resin having a polymer network structure containing polymers having repeating units derived from acrylic or methacrylic monomers or oligomers, and inorganic nanoparticles disposed within the resin, and that have a refractive index greater than 1.7 and a glass transition temperature greater than 60°C (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2019-533040 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a demand for a high refractive index curable composition that can realize an even higher refractive index and that can produce a high refractive index cured product that has both a high glass transition temperature and excellent transparency.

[0006] The present invention aims to solve the above-mentioned problems of the prior art and to achieve the following object: That is, the present invention aims to provide a high refractive index curable composition that can produce a high refractive index cured product that has a high refractive index, a high glass transition temperature, and excellent transparency. [Means for solving the problem]

[0007] The means for solving the above problems are as follows: <1> A polyfunctional (meth)acrylate compound (A) represented by the following general formula (1), a monofunctional (meth)acrylate compound (B) having a naphthalene skeleton; Inorganic nanoparticles; and a polymerization initiator. [ka] In the general formula (1), R 1 each independently represents hydrogen or a methyl group; l, m, n, o, p, q, r, s, t, u, v, and w each independently represent an integer of 0 to 10; a and c are 1; b and d are each independently 0 or 1; and a+b+c+d is 2, 3, or 4. <2> The above composition further containing another (meth)acrylate compound (C). <1> The high refractive index curable composition is as described in 1. <3> The mass ratio (A / B) of the polyfunctional (meth)acrylate compound (A) to the monofunctional (meth)acrylate compound (B) is 1 / 99 to 70 / 30. <1> or <2> The high refractive index curable composition is as described in 1. <4> The total content of the polyfunctional (meth)acrylate compound (A) and the monofunctional (meth)acrylate compound (B) is 15% by mass or more and 45% by mass or less. <1> from <3> The high refractive index curable composition according to any one of the above items. <5> The content of the inorganic nanoparticles is 55% by mass or more and 85% by mass or less. <1> from <4> The high refractive index curable composition according to any one of the above items. <6> The inorganic nanoparticles are titanium oxide. <1> from <5> The high refractive index curable composition according to any one of the above items. <7> The particle diameter of the inorganic nanoparticles is 1 nm or more and 100 nm or less. <1> from <6> The high refractive index curable composition according to any one of the above items. <8> The aforementioned <1> from <7> 1. A high refractive index cured product obtained by photocuring the high refractive index curable composition according to any one of the above items. <9> The refractive index n at a wavelength of 636 nm is 1.80 or more. <8> 2. The high refractive index cured product according to claim 1. <10> The glass transition temperature measured by differential scanning calorimetry is 60°C or higher. <8> or <9> 2. The high refractive index cured product according to claim 1. <11> The haze is 1.0 or less. <8> from <10> 1. A high refractive index cured product according to any one of the preceding claims. [Effects of the Invention]

[0008] According to the present invention, it is possible to solve the above-mentioned conventional problems, achieve the above-mentioned object, and provide a high refractive index curable composition that can produce a high refractive index cured product that combines a high refractive index, a high glass transition temperature, and excellent transparency. DETAILED DESCRIPTION OF THE INVENTION

[0009] (High refractive index curable composition) The high refractive index curable composition of the present embodiment contains a polyfunctional (meth)acrylate compound (A) represented by the following general formula (1), a monofunctional (meth)acrylate compound (B) having a naphthalene skeleton, inorganic nanoparticles, and a polymerization initiator, and further contains other components such as another (meth)acrylate compound (C) and a solvent, as necessary.

[0010] There are many optical product technologies that utilize the reflection and refraction of light, and the refractive index greatly affects the properties of the product. For collimating lenses used in optical transceivers and other devices that require extremely high optical properties, aspherical lenses made by molding glass are the mainstream. These lenses feature a high refractive index of 1.8 or higher, allowing for the production of high-quality lenses with minimal aberration. However, issues remain, such as increased production costs due to mold deterioration caused by the high temperatures and cooling processes in the molding process caused by using glass, and the difficulty of designing compact lenses in line with the trend toward miniaturization of optical transceivers. As an alternative method, a nanoimprint manufacturing process using a resin composition is being considered.

[0011] One method for increasing the refractive index of resins used in such applications is to introduce chemical structures with high refractive indices. Specific examples of chemical structures include phenyl groups and sulfur (see, for example, Patent Document 1). However, high-refractive-index materials made solely of resins with high refractive indices and many rigid chemical structures introduced into them lack thermoplasticity and are difficult to mold (see, for example, literature: Higashihara et al., Graduate School of Science and Engineering, Tokyo Institute of Technology, Society of Polymer Science, Preprint, 2011). Therefore, it is difficult to achieve a refractive index of 1.8 or higher and easy moldability with a single resin, and the reality is that no usable resins exist.

[0012] Another method for increasing the refractive index is to add metal oxide nanoparticles with a high refractive index to a resin to create a composite material. However, because easily moldable resins have a relatively low refractive index, a large amount of metal oxide nanoparticles must be added to further increase the refractive index, which makes it difficult to achieve both a high glass transition temperature and transparency in the composite material. Therefore, there remains a need for the development of a high refractive index curable composition that can produce a high refractive index cured product that has a high refractive index, a high glass transition temperature, and excellent transparency.

[0013] As a result of intensive research conducted by the present inventors to solve the above-mentioned conventional problems and achieve the above-mentioned object, the present inventors have found that the above-mentioned high refractive index curable composition can be used to produce a high refractive index cured product that has a high refractive index, a high glass transition temperature, and excellent transparency, and have thereby completed the present invention. According to the high refractive index curable composition of this embodiment, by including a polyfunctional (meth)acrylate compound (A) having a more rigid naphthalene structure as the main skeleton, it is possible to improve the crosslink density of the resin while suppressing a decrease in the refractive index when blended with a high refractive index monomer and cured. Furthermore, by including metal nanoparticles that exhibit a higher refractive index than organic materials, it is possible to achieve an even higher refractive index. Furthermore, by blending with a monofunctional (meth)acrylate compound (B) that is easily moldable and has a relatively high refractive index, it is possible to obtain a high refractive index curable composition that can produce a high refractive index cured product that combines a high refractive index and transparency.

[0014] <Polyfunctional (meth)acrylate compound (A)> The polyfunctional (meth)acrylate compound (A) is represented by the following general formula (1) and is a polyfunctional (meth)acrylate compound having a naphthalene skeleton and difunctional to tetrafunctional (meth)acrylate groups. [ka] In the general formula (1), R 1 each independently represents hydrogen or a methyl group; l, m, n, o, p, q, r, s, t, u, v, and w each independently represent an integer of 0 to 10; a and c are 1; b and d are each independently 0 or 1; and a+b+c+d is 2, 3, or 4.

[0015] Substituent a and substituent c are defined as having subscripts a and c of 1, respectively, and substituent a and substituent c are present. Substituent b and substituent d are defined to be present when the subscripts b and d are 1 and absent when they are 0 (zero), respectively. a+b+c+d is 2, 3 or 4. In other words, the polyfunctional (meth)acrylate compound (A) is a difunctional to tetrafunctional (meth)acrylate compound. a+b+c+d is preferably 2 or 3, and more preferably 2.

[0016] The substituent a and the substituent c in the general formula (1) may be the same as or different from each other, but are preferably different from each other in that they have the molecular asymmetry of the polyfunctional (meth)acrylate compound (A), can increase the content of the polyfunctional (meth)acrylate compound (A) in the high refractive index curable composition, and can achieve a higher refractive index and a higher Tg. When the substituent b and / or the substituent d are present, the substituent b and / or the substituent d may be the same as or different from the substituent a and / or the substituent c.

[0017] In each of the substituents a, b, c, and d, the l, m, n, o, p, q, r, s, t, u, v, and w each independently represent an integer of 0 to 10. The l, m, n, o, p, q, r, s, t, u, v, and w each independently represent preferably 0 to 5, more preferably 0 to 3, and even more preferably 0 to 2.

[0018] The polyfunctional (meth)acrylate compound (A) is not particularly limited and can be appropriately selected depending on the purpose. For example, 2,7-naphthalene diacrylate represented by the following structural formula (in the general formula (1), (a, b, c, d) = (1, 0, 1, 0), l = m = n = r = s = t = 0 in the substituents a and c, R 1 =H); 2(2-acryloyl(7-(acryloyloxy)ethoxy)naphthalene (in the general formula (1), (a, b, c, d) = (1, 0, 1, 0), l = m = n = 0 in the substituent a, R 1 =H, r=0, t=1, s=2 in the substituent c, R 1 =H).

[0019] [ka]

[0020] The method for synthesizing the polyfunctional (meth)acrylate compound (A) is not particularly limited and can be appropriately selected depending on the purpose. For example, a method for synthesizing a difunctional to tetrafunctional hydroxynaphthalene having partial structures of substituents a, b, c, and d as necessary, and X-{(CH2) l -{O-(CH2) n} m}-OH, and then reacting with a halogenated alcohol represented by X-CO-CR 1 and a synthesis method in which the compound is reacted with a halogenated (meth)acrylic acid represented by =CH2 (for example, acrylic acid chloride). Here, X represents a halogen such as Cl, Br, or I.

[0021] The content of the polyfunctional (meth)acrylate compound (A) is not particularly limited and can be appropriately selected depending on the purpose. However, it is preferably from 1 to 70% by mass, more preferably from 1 to 50% by mass, from 1 to 40% by mass, or from 5 to 40% by mass, and even more preferably from 10 to 35% by mass, relative to the total amount of polymerizable compounds in the high refractive index curable composition. The polymerizable compound is a component containing the polyfunctional (meth)acrylate compound (A) and the monofunctional (meth)acrylate compound (B), and further containing, as necessary, another (meth)acrylate compound (C) and another polymerizable compound.

[0022] <Monofunctional (meth)acrylate compound (B)> The monofunctional (meth)acrylate compound (B) is a monofunctional (meth)acrylate compound having a naphthalene skeleton and a monofunctional (meth)acrylate group. The monofunctional (meth)acrylate compound (B) is preferably a compound represented by the following general formula (2). [ka] In the general formula (2), R 1 each independently represents hydrogen or a methyl group, and l, m, and n each independently represents an integer of 0 to 10.

[0023] The l, m, and n each independently represent an integer of 0 to 10. The 1 is preferably 0 to 5, more preferably 0 to 3, and even more preferably 0 to 2. The m is preferably 0 to 5, more preferably 0 to 3, and even more preferably 0 to 2. The above n is preferably 0 to 5, more preferably 0 to 3, and even more preferably 0 to 2.

[0024] The monofunctional (meth)acrylate compound (B) is not particularly limited and can be appropriately selected depending on the purpose. For example, 1-naphthalenemethyl acrylate (NMT-A; in the general formula (2), l=1, n=m=0, R 1 =H).

[0025] The content of the monofunctional (meth)acrylate compound (B) is not particularly limited and can be appropriately selected depending on the purpose. However, it is preferably from 30% by mass to 99% by mass, more preferably from 40% by mass to 99% by mass, even more preferably from 50% by mass to 99% by mass, and particularly preferably from 60% by mass to 99% by mass, relative to the total amount of polymerizable compounds in the high refractive index curable composition.

[0026] The mass ratio (A / B) of the polyfunctional (meth)acrylate compound (A) to the monofunctional (meth)acrylate compound (B) is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 / 99 to 70 / 30, more preferably 1 / 99 to 50 / 50, 1 / 99 to 40 / 60, or 5 / 95 to 40 / 60, and even more preferably 10 / 90 to 35 / 65.

[0027] The total content of the polyfunctional (meth)acrylate compound (A) and the monofunctional (meth)acrylate compound (B) is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 15% by mass or more and 45% by mass or less, more preferably 15% by mass or more and 40% by mass or less, and even more preferably 20% by mass or more and 30% by mass or less.

[0028] <Other (meth)acrylate compounds (C)> The high refractive index curable composition may contain other (meth)acrylate compounds (C) as needed. The other (meth)acrylate compound (C) is not particularly limited as long as it is a (meth)acrylate compound having a (meth)acrylate group other than the polyfunctional (meth)acrylate compound (A) and the monofunctional (meth)acrylate compound (B), and can be appropriately selected depending on the purpose. Examples thereof include alkyl (meth)acrylate, cycloalkyl (meth)acrylate, bicycloalkyl (meth)acrylate, tricycloalkyl (meth)acrylate, heterocycloalkyl (meth)acrylate, heterobicycloalkyl (meth)acrylate, fluorene-containing (meth)acrylate, hydroxyl group-containing (meth)acrylate, and trimethylolpropane tri(meth)acrylate. Among these, (meth)acrylates having a cyclic structure such as a fluorene structure are preferred from the viewpoint of increasing the refractive index, and polyfunctional (meth)acrylates are preferred from the viewpoint of the thermal stability of the cured product.

[0029] <Inorganic nanoparticles> The inorganic nanoparticles are not particularly limited as long as they are nanoparticles with a high refractive index, and can be appropriately selected depending on the purpose. Examples include metal oxide nanoparticles, metal nanoparticles, and alloy nanoparticles. Examples of materials for the metal oxide nanoparticles include titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, barium titanate (BaTiO3), indium tin oxide (ITO), and antimony-doped tin oxide (ATO). Examples of the metal of the metal nanoparticles include iron, zinc, tungsten, platinum, etc. Examples of the alloy of the alloy nanoparticles include alloys containing the above metals. These may be used alone or in combination of two or more. Among these, metal oxide nanoparticles are preferred, and titanium oxide is more preferred.

[0030] The particle size of the inorganic nanoparticles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 nm or more and 100 nm or less, and more preferably 5 nm or more and 50 nm or less. When the measurement sample is a high refractive index curable composition or dispersion containing inorganic nanoparticles, the particle diameter can be measured by a dynamic light scattering method. When the measurement sample is a high refractive index cured product, the particle diameter can be measured by observing a fragment using a transmission electron microscope (TEM) and calculating the circle equivalent diameter within the observation field.

[0031] The content of the inorganic nanoparticles is not particularly limited and can be appropriately selected depending on the purpose. However, the content is preferably 55% by mass or more and 85% by mass or less, more preferably 60% by mass or more and 80% by mass or less, and even more preferably 70% by mass or more and 80% by mass or less, relative to the total amount of the high refractive index curable composition.

[0032] <Polymerization initiator> The polymerization initiator is preferably a photopolymerization initiator that generates radicals upon irradiation with visible light or ultraviolet light having a wavelength shorter than 450 nm, and examples thereof include acylphosphine oxide polymerization initiators such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane- acetophenone-based polymerization initiators such as benzoin and 2,2-dimethoxy-1,2-diphenylethan-1-one; benzoin-based polymerization initiators such as benzophenone, [4-(methylphenylthio)phenyl]phenylmethanone, 4-hydroxybenzophenone, 4-phenylbenzophenone, and 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone; and thioxanthone-based polymerization initiators such as 2-chlorothioxanthone and 2,4-diethylthioxanthone. These may be used alone or in combination of two or more.

[0033] The content of the polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the polymerizable compound.

[0034] <Other ingredients> The other components are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include solvents.

[0035] The solvent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include alcohols such as methanol, ethanol, and isopropyl alcohol; ethers such as tetrahydrofuran and ethyl methyl ether; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, 1-methoxy-2-propanol (propylene glycol monomethyl ether, PGME), and propylene glycol monobutyl ether (PGB); methyl cellosolve acetate, ethyl cellosolve acetate, and butyl cellosolve acetate. alkylene glycol monoalkyl ether acetates such as acetate, propylene glycol methyl ether acetate (PGMEA), and 3-methoxybutyl-1-acetate; aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), methyl amyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; and esters such as ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-2-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl acetate, butyl acetate, methyl lactate, and ethyl lactate. These may be used alone or in combination of two or more.

[0036] [viscosity] The viscosity of the high refractive index curable composition at 25° C. is preferably 1000 mPa or less, more preferably 500 mPa or less, and even more preferably 300 mPa or less. When the viscosity of the high refractive index curable composition at 25°C is 1000 mPa or less, the composition has low viscosity and excellent moldability, which is advantageous in that a high refractive index cured product can be produced using a coating process that requires low viscosity, such as a spin coater. The viscosity can be measured using a rheometer (for example, device name: Rheometer AR-G2, manufactured by TA Instruments Co., Ltd.).

[0037] [Method for preparing high refractive index curable composition] The method for preparing the high refractive index curable composition is not particularly limited and can be appropriately selected depending on the purpose. For example, a method of mixing the polyfunctional (meth)acrylate compound (A), the monofunctional (meth)acrylate compound (B), the inorganic nanoparticles, the polymerization initiator, and other components as needed can be mentioned.

[0038] (High refractive index cured product) The high refractive index cured product is a cured product obtained by photocuring the high refractive index curable composition of the present embodiment described above. The method for photocuring the high refractive index curable composition is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a method of applying the high refractive index curable composition onto a substrate and irradiating it with light to photocure the high refractive index curable composition; and a method of filling the high refractive index curable composition into a molding die and irradiating it with light to photocure the high refractive index curable composition. This allows the production of the high refractive index cured product.

[0039] The method for applying the high refractive index curable composition onto the substrate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the method include a method of applying the high refractive index curable composition to the entire surface of the substrate in a uniform thickness using a bar coater, a spin coater, or the like; and a method of applying the high refractive index curable composition to the substrate in a desired pattern shape using screen printing or the like. The high refractive index curable composition has an advantage in that the viscosity can be adjusted by blending the monofunctional (meth)acrylate compound (B), which has a relatively low viscosity, with a solvent or the like as needed, and that a high refractive index cured product can be produced using a coating process that has excellent moldability and requires a low viscosity.

[0040] Examples of the light irradiation include light irradiation using a high-pressure mercury lamp, a metal halide lamp, and a UV-LED irradiator. When the high refractive index curable composition contains a solvent, the composition may be subjected to a treatment for removing the solvent by heating, reducing pressure, or the like, as necessary, before photocuring.

[0041] [Refractive Index] The high refractive index cured product of this embodiment can have a high refractive index, specifically, the refractive index n of the high refractive index cured product at a wavelength of 636 nm can be 1.80 or more. The refractive index n of the high refractive index cured product at a wavelength of 636 nm is preferably 1.80 or more, and more preferably 1.82 or more. The refractive index of the high refractive index cured product at a wavelength of 636 nm can be measured using a refractometer (for example, device name: Prism Coupler 2010 / M, manufactured by Metricon Japan Co., Ltd.).

[0042] [Glass transition temperature (Tg)] The high refractive index cured product of this embodiment has a high glass transition temperature and excellent heat resistance, specifically, a Tg of 60° C. or higher. The glass transition temperature (Tg) of the high refractive index cured product is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 75°C or higher. The glass transition temperature (Tg) can be measured using a differential scanning calorimeter (for example, device name: DSC 7000X, manufactured by Hitachi High-Tech Corporation).

[0043] The high refractive index cured product of this embodiment is transparent, and specifically, can have a total light transmittance of 85% or more and a haze of 1.0 or less. The total light transmittance is preferably 85% or more, and more preferably 88% or more. The haze is preferably 1.0 or less, more preferably 0.8 or less, and even more preferably 0.5 or less. The total light transmittance can be measured using a high refractive index cured product having an average thickness of 5 μm as a measurement sample with a haze meter (for example, NDH 7000SP, manufactured by Nippon Denshoku Industries Co., Ltd.). The haze can be measured in accordance with JIS K 7136 using a high refractive index cured product having an average thickness of 5 μm as a measurement sample with a haze meter (for example, NDH 7000SP, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0044] The average thickness of the high refractive index cured product is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 μm or more and 40 μm or less, and more preferably 1 μm or more and 10 μm or less. Here, the average thickness is the arithmetic mean value when measurements are taken at 10 random locations.

[0045] [Application] The high refractive index cured product of this embodiment can be used as a high refractive index curable composition capable of producing a high refractive index cured product having a high refractive index, a high glass transition temperature, and excellent transparency. Specifically, it can be used for optical components such as lenses, filters, optical fibers, mirrors, refractive optical elements, and diffractive optical elements; light-emitting device components, light-absorbing device components, and display device components.

[0046] The high refractive index cured product of this embodiment and the high refractive index cured product can be used for applications such as thinning optical lenses such as microlens arrays (see, for example, JP 2008-060121 A) and for applications such as improving the light concentration rate of optical transceivers (see, for example, JP 2004-096091 A). In addition, by forming a laminated structure that gradually eliminates the refractive index difference between air and the substrate, it can be suitably used for anti-reflective coating applications for display devices such as solar cells and displays (see, for example, JP 2022-106002 A), which can contribute to improving the performance of optical products. [Example]

[0047] Examples of the present invention will be described below, but the present invention is not limited to these examples in any way.

[0048] <Synthesis Example 1: Synthesis of 2,7-naphthalenediacrylate> A 200 mL three-neck flask was charged with 6.40 g (40 mmol) of 2,7-dihydroxynaphthalene (Tokyo Chemical Industry Co., Ltd.), 8.90 g (88 mmol) of triethylamine (Tokyo Chemical Industry Co., Ltd.), and 70 g of ultra-dehydrated acetone (Fujifilm Wako Pure Chemical Industries, Ltd.) under an inert atmosphere. The solution was cooled to 5 °C, and then 7.97 g (88 mmol) of acrylic acid chloride (Tokyo Chemical Industry Co., Ltd.) was slowly added dropwise while stirring, ensuring the solution temperature did not exceed 10 °C. After the addition was complete, the mixture was stirred at room temperature for 24 hours. Water was then added to the reaction solution, and the precipitated solid was filtered and separated with dichloromethane and distilled water. The organic layer was dried over magnesium sulfate, filtered, and the organic solvent was removed using a rotary evaporator. The mixture was then dried overnight under reduced pressure at 40 °C, yielding 8.46 g (78.8% yield) of Compound 1 as a pale yellow solid. The obtained synthetic product 1 was subjected to NMR measurement using a nuclear magnetic resonance apparatus (NMR apparatus, apparatus name: JNM-EXZ400R / S3, manufactured by JEOL Ltd.).

[0049] Regarding the obtained compound 1, 1 The H NMR measurement results and structural formula are shown below. 1 H NMR (DMSO-d6,400MHz):8.05-8.02(d,2H),7.75-7.74(d,2H),7.39-7.36(d,2H),6.61-6.56(dd,2H),6.50-6.43(dd,2H),6.21-6.17(dd,2H).

[0050] [ka]

[0051] <Synthesis Example 2: Synthesis of 2-acryloyl(7-(acryloyloxy)ethoxy)naphthalene> A 200 mL three-neck flask was charged with 120 g of distilled water and 4.85 g (121 mmol) of sodium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd.) and stirred. After confirming the dissolution of the sodium hydroxide, 9.61 g (60 mmol) of 2,7-dihydroxynaphthalene (Tokyo Chemical Industry Co., Ltd.) was added and stirred at room temperature for 2 hours. Then, 15.2 g (121 mmol) of 2-bromoethanol (Tokyo Chemical Industry Co., Ltd.) was added dropwise, and the mixture was heated and stirred at 85°C for 6 hours. After cooling, the mixture was stirred at room temperature overnight. The next day, the mixture was filtered, washed, and dried under reduced pressure at 40°C overnight to obtain 9.44 g of a black solid. The resulting solid was placed in a 200 mL three-neck flask under an inert atmosphere, along with 6.88 g (76 mmol) of 2,7-dihydroxynaphthalene (Tokyo Chemical Industry Co., Ltd.), 7.69 g (76 mmol) of triethylamine (Tokyo Chemical Industry Co., Ltd.), and 70 g of ultra-dehydrated acetone (Fujifilm Wako Pure Chemical Industries Co., Ltd.). The solution was cooled to 5°C, and then 6.88 g (76 mmol) of acrylic acid chloride (Tokyo Chemical Industry Co., Ltd.) was slowly added dropwise while stirring, ensuring that the solution temperature did not exceed 10°C. After the addition was complete, the mixture was stirred at room temperature for 24 hours. Water was then added to the reaction solution, and the precipitated solid was filtered and separated using dichloromethane and distilled water. The organic layer was dried over magnesium sulfate and filtered, after which the organic solvent was removed using a rotary evaporator. The residue was dried overnight under reduced pressure at 40°C to obtain a pale red solid, Compound 2. This was then treated with silica gel chromatography (solvent: chloroform:hexane:ethyl acetate = 5:4:1, volume ratio) to obtain 4.62 g of a white solid (yield 24.7%).

[0052] Regarding the obtained compound 2, 1 The H NMR measurement results and structural formula are shown below. 1 H NMR(DMSO-d6,400MHz):7.90-7.86(d,2H),7.59-7.58(d,1H),7.37-7.36(d,1H ),7,19-7.16(m,2H),6.59-5.94(m,6H),4.52-4.51(d,2H),4.36-4.33(d,2H).

[0053] [ka]

[0054] Example 1 A high refractive index curable composition of Example 1 was prepared by blending 5 parts by mass of Compound 1, 25 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 200 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (70 parts by mass of titanium oxide and 130 parts by mass of solvent), 1.4 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.7 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0055] The high refractive index curable composition was then applied to a glass slide (product name: S9111, manufactured by Matsunami Glass Industry Co., Ltd.) using a wireless bar coater (device name: OSP-08, manufactured by OSG System Products Co., Ltd.) so that the average thickness of the coating film was 8 μm. Next, to remove the solvent (MEK) contained in the titanium oxide dispersion, a drying process was carried out at 60°C for 30 minutes using a perfect oven (device name: PHH-102, manufactured by Espec Corporation). After removing the solvent, a nitrogen purge was carried out for 1 minute, and the coating was then dried under a nitrogen atmosphere using a UV irradiation device (device name: iGrandage ECS-401GX, manufactured by iGraphics Co., Ltd.) equipped with a high-pressure mercury lamp (device name: H04-L41, manufactured by iGraphics Co., Ltd.) at an illuminance of 2 J / cm. 2 A high refractive index cured product of Example 1 having an average thickness of 5 μm was prepared by irradiating the light with light.

[0056] <Evaluation> The high refractive index cured products thus produced were evaluated by measuring the glass transition temperature (Tg), refractive index, total light transmittance, and haze according to the following procedure. The results are shown in Table 1.

[0057] <<Refractive index of high refractive index cured product>> The refractive index of the high refractive index cured product was measured at a wavelength of 636 nm using a refractometer (device name: Prism Coupler 2010 / M, manufactured by Metricon Japan Co., Ltd.) and evaluated according to the following evaluation criteria. -Evaluation criteria- ⊚: The refractive index at a wavelength of 636 nm is 1.82 or more. ◯: The refractive index at a wavelength of 636 nm is 1.80 or more and less than 1.82. ×: The refractive index at a wavelength of 636 nm is less than 1.80.

[0058] <<Glass transition temperature (Tg) of high refractive index cured product>> The Tg of the high refractive index cured product was measured by peeling the high refractive index cured product from the slide glass and using a differential scanning calorimeter (device name: DSC 7000X, manufactured by Hitachi High-Technologies Corporation), and evaluated according to the following evaluation criteria. -Evaluation criteria- ◎: Tg is 75°C or higher. ◯: Tg is 60°C or higher and lower than 75°C. ×: Tg is less than 60°C.

[0059] <<Total light transmittance of high refractive index cured product>> The total light transmittance of the high refractive index cured product was measured using a haze meter (device name: NDH 7000SP, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K 7136-1, and evaluated based on the following evaluation criteria. -Evaluation criteria- ⊚: Total light transmittance is 88% or more. ◯: Total light transmittance is 85% or more and less than 88%. ×: The total light transmittance is less than 85%.

[0060] <<Haze of high refractive index cured products>> The haze of the high refractive index cured product was measured in accordance with JIS K 7136 using a haze meter (device name: NDH 7000SP, manufactured by Nippon Denshoku Industries Co., Ltd.), and evaluated based on the following evaluation criteria. -Evaluation criteria- ⊚: Haze is 0.5 or less. ◯: Haze is more than 0.5 and 1.0 or less. ×: Haze is more than 1.0.

[0061] Example 2 A high refractive index curable composition of Example 2 was prepared by blending 5 parts by mass of Compound 2, 25 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 200 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (70 parts by mass of titanium oxide and 130 parts by mass of solvent), 1.4 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.7 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0062] Next, a high refractive index cured product of Example 2 was produced and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Example 2 was used. The results are shown in Table 1.

[0063] Example 3 A high refractive index curable composition of Example 3 was prepared by blending 10 parts by mass of Compound 2, 20 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 200 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (70 parts by mass of titanium oxide and 130 parts by mass of solvent), 1.4 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.7 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0064] Next, a high refractive index cured product of Example 3 was prepared and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Example 3 was used. The results are shown in Table 1.

[0065] Example 4 A high refractive index curable composition of Example 4 was prepared by blending 3 parts by mass of Compound 1, 17 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 229 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (80 parts by mass of titanium oxide and 149 parts by mass of solvent), 0.9 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.3 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0066] Next, a high refractive index cured product of Example 4 was prepared and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Example 4 was used. The results are shown in Table 1.

[0067] (Comparative Example 1) A high refractive index curable composition of Comparative Example 1 was prepared by blending 30 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 200 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (70 parts by mass of titanium oxide and 130 parts by mass of solvent), 1.4 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.7 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0068] Next, a high refractive index cured product of Comparative Example 1 was prepared and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 1 was used. The results are shown in Table 2.

[0069] (Comparative Example 2) A high refractive index curable composition of Comparative Example 2 was prepared by blending 30 parts by mass of dimethyloltricyclodecane diacrylate (trade name: Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.), 200 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (70 parts by mass of titanium oxide and 130 parts by mass of solvent), 1.4 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.7 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0070] Next, a high refractive index cured product of Comparative Example 2 was prepared and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 2 was used. The results are shown in Table 2.

[0071] (Comparative Example 3) A high refractive index curable composition of Comparative Example 3 was prepared by blending 20 parts by mass of dimethyloltricyclodecane diacrylate (trade name: Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.), 229 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (80 parts by mass of titanium oxide and 149 parts by mass of solvent), 0.9 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.3 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0072] Next, a high refractive index cured product of Comparative Example 3 was prepared and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 3 was used. The results are shown in Table 2.

[0073] Comparative Example 4 A high refractive index curable composition of Comparative Example 4 was prepared by blending 10 parts by mass of dimethyloltricyclodecane diacrylate (trade name: Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.), 257 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (90 parts by mass of titanium oxide and 167 parts by mass of solvent), 0.3 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.1 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0074] Next, a high refractive index cured product of Comparative Example 4 was produced in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 4 was used, but film formation was not possible due to cracks in the film and precipitation of titanium oxide solids. The results are shown in Table 2.

[0075] (Comparative Example 5) A high refractive index curable composition of Comparative Example 5 was prepared by blending 30 parts by mass of a fluorene derivative diacrylate (trade name: F5710, manufactured by Osaka Gas Chemicals Co., Ltd.), 200 parts by mass of a titanium oxide dispersion (trade name: NS408, manufactured by Teika Corporation, solvent: MEK, solids content: 35% by mass, particle size measured by dynamic light scattering: 10 nm to 30 nm) (70 parts by mass of titanium oxide and 130 parts by mass of solvent), 1.4 parts by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad1173, manufactured by IGM Resins BV) as a polymerization initiator, and 0.7 parts by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0076] Next, a high refractive index cured product of Comparative Example 5 was prepared in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 5 was used, and evaluation was carried out. The results are shown in Table 2. Note that when the refractive index was measured, there was a large variation in the refractive index depending on the measurement location, and the measured value could not be identified.

[0077] (Comparative Example 6) A high refractive index curable composition of Comparative Example 6 was prepared by blending 15 parts by mass of Compound 1, 85 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1 part by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad 1173, manufactured by IGM Resins BV) as a polymerization initiator, and 1 part by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0078] Next, a high refractive index cured product of Comparative Example 6 was prepared and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 6 was used. The results are shown in Table 2.

[0079] (Comparative Example 7) A high refractive index curable composition of Comparative Example 7 was prepared by blending 15 parts by mass of Compound 2, 85 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1 part by mass of 2-hydroxy-2-methylpropiophenone (trade name: Omnirad1173, manufactured by IGM Resins BV) as a polymerization initiator, and 1 part by mass of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO H, manufactured by IGM Resins BV).

[0080] Next, a high refractive index cured product of Comparative Example 7 was prepared and evaluated in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 7 was used. The results are shown in Table 2.

[0081] [Table 1]

[0082] [Table 2]

[0083] The high refractive index curable compositions of Examples 1 to 4 gave high refractive index cured products that had excellent refractive indices of 1.82 or more and Tg values ​​of 75°C or more, and had excellent transparency with haze values ​​of 1.0 or less, demonstrating that it was possible to produce high refractive index cured products that combined a high refractive index, a high glass transition temperature, and excellent transparency.

[0084] On the other hand, the high refractive index curable compositions of Comparative Examples 1 to 5, which did not contain a polyfunctional (meth)acrylate compound (A), were unable to achieve both a high refractive index and a high glass transition temperature in the resulting high refractive index cured products. Additionally, in Comparative Examples 2 to 4, as the mass ratio of inorganic nanoparticles increased, transparency decreased, resulting in film formation being impossible. Comparative Example 5, which contained another monofunctional (meth)acrylate compound (C), failed to produce a uniform cured product, resulting in a haze of 1.5 and a lack of transparency. Furthermore, in the high refractive index curable compositions of Comparative Examples 6 and 7, which did not contain inorganic nanoparticles, the refractive index of the obtained high refractive index cured products was significantly below 1.80, and an excellent high refractive index could not be achieved.

Claims

1. A polyfunctional (meth)acrylate compound (A) represented by the following general formula (1), a monofunctional (meth)acrylate compound (B) having a naphthalene skeleton; Inorganic nanoparticles; A high refractive index curable composition comprising: 【Chemistry 1】 In the general formula (1), R １ each independently represents hydrogen or a methyl group; l, m, n, o, p, q, r, s, t, u, v, and w each independently represent an integer of 0 to 10; a and c are 1; b and d are each independently 0 or 1; and a+b+c+d is 2, 3, or 4.

2. The high refractive index curable composition according to claim 1 , further comprising another (meth)acrylate compound (C).

3. 2. The high refractive index curable composition according to claim 1, wherein a mass ratio (A / B) of the polyfunctional (meth)acrylate compound (A) to the monofunctional (meth)acrylate compound (B) is 1 / 99 to 70 / 30.

4. The high refractive index curable composition according to claim 1, wherein a total content of the polyfunctional (meth)acrylate compound (A) and the monofunctional (meth)acrylate compound (B) is 15% by mass or more and 45% by mass or less.

5. The high refractive index curable composition according to claim 1 , wherein the content of the inorganic nanoparticles is 55% by mass or more and 85% by mass or less.

6. The high refractive index curable composition according to claim 1 , wherein the inorganic nanoparticles are titanium oxide.

7. The high refractive index curable composition according to claim 1, wherein the particle diameter of the inorganic nanoparticles is 1 nm or more and 100 nm or less.

8. A high refractive index cured product obtained by photocuring the high refractive index curable composition according to any one of claims 1 to 7.

9. The high refractive index cured product according to claim 8, which has a refractive index n of 1.80 or more at a wavelength of 636 nm.

10. 9. The high refractive index cured product according to claim 8, which has a glass transition temperature of 60°C or higher as measured by differential scanning calorimetry.

11. 9. The high refractive index cured product according to claim 8, which has a haze of 1.0 or less.

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