High refractive index curable composition and high refractive index cured product

Abstract

To provide a high refractive index curable composition that has low viscosity and excellent moldability, and that is capable of forming a high refractive index cured product capable of achieving both a high refractive index and thermal stability.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, 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] It has been reported that by mixing o-phenylbenzyl acrylate (OPBA) and p-phenylbenzyl acrylate (PPBA), which are isomers of phenylbenzyl acrylate, in a specific ratio, it is possible to provide a composition with a high refractive index and low viscosity suitable as an optical material, as well as a cured product with a high refractive index (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-82387 Summary of the Invention [Problem to be solved by the invention]

[0005] However, these compositions are difficult to apply to coating processes such as spin coating, which require even lower viscosities. Therefore, there is a demand for high refractive index curable compositions that have low viscosity, excellent moldability, and can produce high refractive index cured products that have both a high refractive index and a high glass transition index.

[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 has low viscosity, excellent moldability, and is capable of producing a high refractive index cured product that is capable of achieving both a high refractive index and thermal stability. [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; 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 viscosity at 25°C is 1000 mPa or less. <1> The high refractive index curable composition is as described in 1. <3> The above composition further containing another (meth)acrylate compound (C). <1> or <2> The high refractive index curable composition is as described in 1. <4> The content of the polyfunctional (meth)acrylate compound (A) is 1% by mass or more and 70% 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 monofunctional (meth)acrylate compound (B) is 30% by mass or more and 99% by mass or less. <1> from <4> The high refractive index curable composition according to any one of the above items. <6> The above-mentioned formula (1) in which the substituent a and the substituent c are different from each other <1> from <5> The high refractive index curable composition according to any one of the above items. <7> The aforementioned <1> from <6> 1. A high refractive index cured product obtained by photocuring the high refractive index curable composition according to any one of the above items. <8> The refractive index n at a wavelength of 636 nm is 1.60 or more. <7> 2. The high refractive index cured product according to claim 1. <9> The glass transition temperature measured by differential scanning calorimetry is 60°C or higher. <7> or <8> 2. The high refractive index cured product according to claim 1. [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 has low viscosity, excellent moldability, and is capable of producing a high refractive index cured product that is capable of achieving both a high refractive index and thermal stability. 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, and a polymerization initiator, and may further contain 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 molded from glass are the mainstream. These lenses feature a high refractive index of 1.8 or higher, enabling the production of high-quality lenses with minimal aberration. However, issues remain, such as increased production costs due to mold deterioration caused by high temperatures and cooling during the molding process, and the difficulty of designing compact lenses in line with the trend toward miniaturization of optical transceivers. As an alternative, a nanoimprint manufacturing process using a resin composition is being considered. However, because the film is formed using a spin coater or similar, the resin composition must have low viscosity.

[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 high-refractive-index metal oxide nanoparticles to a resin to create a composite material. However, because easily moldable resins have relatively low refractive indices, a large amount of metal oxide nanoparticles must be added to increase the refractive index, which makes it difficult to achieve both a high glass transition and low viscosity in the composite material. Therefore, there remains a need for the development of a high refractive index curable composition that has low viscosity, excellent moldability, and is capable of producing a high refractive index cured product that is both high refractive index and thermal stability.

[0013] As mentioned above, when designing a high refractive index material, it is important to have a resin material that combines high properties (high refractive index, high Tg) with ease of molding (low viscosity). The present inventors conducted extensive research to solve the above-mentioned conventional problems and achieve the above-mentioned object, and as a result, they found that the above-mentioned high refractive index curable composition has low viscosity and excellent moldability, and is capable of producing a high refractive index cured product that is able to achieve both a high refractive index and thermal stability, and thus completed the present invention. The high refractive index curable composition of this embodiment contains a polyfunctional (meth)acrylate compound (A) having a more rigid naphthalene structure as the main skeleton, which can improve the crosslink density of the resin while suppressing a decrease in refractive index when blended with a high refractive index monomer and cured. Furthermore, since a high refractive index and a high Tg can be ensured without significantly increasing the viscosity of the monomer during blending, blending with a monofunctional (meth)acrylate compound (B), which is a low-viscosity monomer with a high refractive index, can provide a high refractive index curable composition that has low viscosity, excellent moldability, and can produce a high refractive index cured product that has both a high refractive index and thermal stability.

[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 the high refractive index curable composition. The content of the polyfunctional (meth)acrylate compound (A) is preferably 15% by mass or more and 30% by mass or less relative to the total amount of the polymerizable compounds in the high refractive index curable composition. The polymerizable compound contains the polyfunctional (meth)acrylate compound (A) and the monofunctional (meth)acrylate compound (B), and may further contain other (meth)acrylate compounds (C) and other polymerizable compounds as necessary, excluding the polymerization initiator.

[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 50% by mass to 99% by mass, 60% by mass to 99% by mass, or 60% by mass to 95% by mass, and even more preferably from 65% by mass to 90% by mass, relative to the total amount of the high refractive index curable composition. The content of the monofunctional (meth)acrylate compound (B) is preferably 70% by mass or more and 85% by mass or less based on the total amount of the polymerizable compounds in the high refractive index curable composition.

[0026] <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)acrylates, cycloalkyl or bicycloalkyl (meth)acrylates, heterocycloalkyl (meth)acrylates, heterobicycloalkyl (meth)acrylates, and hydroxyl group-containing (meth)acrylates. Examples of the hydroxyl group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 1-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and phenyl glycidyl ether (meth)acrylate. Among these, (meth)acrylates containing no hydroxyl groups are preferred in terms of curability and the glass transition temperature of the cured product.

[0027] <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.

[0028] 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.

[0029] <Other ingredients> The other components are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include solvents.

[0030] 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.

[0031] [viscosity] The high refractive index curable composition of this embodiment can have a low viscosity, specifically, a viscosity at 25° C. of 1000 mPa or less. 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.).

[0032] [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, there can be mentioned a method in which the polyfunctional (meth)acrylate compound (A), the monofunctional (meth)acrylate compound (B), and other components as needed are mixed, and then the polymerization initiator is mixed.

[0033] (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.

[0034] 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 a low viscosity, which is advantageous in that it has excellent moldability and allows the production of a high refractive index cured product using a coating process that requires a low viscosity.

[0035] 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.

[0036] [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 1.60 or more. The refractive index n of the high refractive index cured product at a wavelength of 636 nm is preferably 1.60 or more, and more preferably 1.62 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.).

[0037] [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 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).

[0038] 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.

[0039] [Application] The high refractive index cured product of this embodiment has low viscosity and excellent moldability, and can be used as a high refractive index curable composition capable of producing a high refractive index cured product that has both a high refractive index and thermal stability. 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.

[0040] 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]

[0041] Examples of the present invention will be described below, but the present invention is not limited to these examples in any way.

[0042] <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.).

[0043] 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).

[0044] [ka]

[0045] <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%).

[0046] 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).

[0047] [ka]

[0048] Example 1 A high refractive index curable composition of Example 1 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). The high refractive index curable composition thus prepared was used to form a coating film with an average thickness of 4 μm on a slide glass (product name: S9111, manufactured by Matsunami Glass Industrial Co., Ltd.), and the coating film was then irradiated at an illuminance of 2 J / cm using a UV irradiation device (product name: iGrandage ECS-401GX, manufactured by iGraphics Co., Ltd.) equipped with a high-pressure mercury lamp (product name: H04-L41, manufactured by iGraphics Co., Ltd.). 2 A high refractive index cured product of Example 1 having an average thickness of 4 μm was prepared by irradiating the light with light.

[0049] <Evaluation> The viscosity of the prepared high refractive index curable composition, the glass transition temperature (Tg) of the high refractive index cured product, and the refractive index of the high refractive index cured product were measured and evaluated according to the following procedures. The results are shown in Table 1.

[0050] <<Viscosity of high refractive index curable composition>> The viscosity of the high refractive index curable composition was measured at 25° C. using a rheometer (device name: Rheometer AR-G2, manufactured by TA Instruments Co., Ltd.) and evaluated based on the following evaluation criteria. -Evaluation criteria- ⊚: Viscosity at 25°C is 500 mPa or less. Good: Viscosity at 25°C is more than 500 mPa and 1000 mPa or less. ×: Viscosity at 25°C exceeds 1000 mPa.

[0051] <<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.

[0052] <<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 1.62 or more. ◯: The refractive index at a wavelength of 636 nm is 1.60 or more and less than 1.62. ×: The refractive index at a wavelength of 636 nm is less than 1.60.

[0053] Example 2 A high refractive index curable composition of Example 2 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: 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).

[0054] Next, a high refractive index cured product of Example 2 was produced in the same manner as in Example 1, except that the high refractive index curable composition of Example 2 was used. The high refractive index curable composition and the high refractive index cured product of Example 2 were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0055] Example 3 A high refractive index curable composition of Example 3 was prepared by blending 30 parts by mass of Compound 2, 70 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).

[0056] Next, a high refractive index cured product of Example 3 was produced in the same manner as in Example 1, except that the high refractive index curable composition of Example 3 was used. The high refractive index curable composition and the high refractive index cured product of Example 3 were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0057] (Comparative Example 1) A high refractive index curable composition of Comparative Example 1 was prepared by blending 100 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).

[0058] Next, a high refractive index cured product of Comparative Example 1 was produced in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 1 was used. The high refractive index curable composition of Comparative Example 1 and the high refractive index cured product were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0059] (Comparative Example 2) A high refractive index curable composition of Comparative Example 2 was prepared by blending 100 parts by mass of dimethyloltricyclodecane diacrylate (trade name: Light Acrylate DCP-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).

[0060] Next, a high refractive index cured product of Comparative Example 2 was produced in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 2 was used. The high refractive index curable composition of Comparative Example 2 and the high refractive index cured product were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0061] (Comparative Example 3) A high refractive index curable composition of Comparative Example 3 was prepared by blending 85 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 15 parts by mass of dimethyloltricyclodecane diacrylate (trade name: DCP-A, manufactured by Shin-Nakamura 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).

[0062] Next, a high refractive index cured product of Comparative Example 3 was produced in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 3 was used. The high refractive index curable composition of Comparative Example 3 and the high refractive index cured product were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0063] Comparative Example 4 A high refractive index curable composition of Comparative Example 4 was prepared by blending 100 parts by mass of fluorene derivative diacrylate (trade name: F5710, manufactured by Osaka Gas Chemicals 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).

[0064] 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. The high refractive index curable composition and the high refractive index cured product of Comparative Example 4 were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0065] (Comparative Example 5) A high refractive index curable composition of Comparative Example 5 was prepared by blending 85 parts by mass of 1-naphthalenemethyl acrylate (trade name: Light Acrylate NMT-A, manufactured by Kyoeisha Chemical Co., Ltd.), 15 parts by mass of fluorene derivative diacrylate (trade name: F5710, manufactured by Osaka Gas Chemicals 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).

[0066] Next, a high refractive index cured product of Comparative Example 5 was produced in the same manner as in Example 1, except that the high refractive index curable composition of Comparative Example 5 was used. The high refractive index curable composition and the high refractive index cured product of Comparative Example 5 were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0067] [Table 1]

[0068] [Table 2]

[0069] It was found that the viscosity of the high refractive index curable composition of Example 1 was almost unchanged compared to NMT-A alone, and was low in viscosity. Furthermore, the resulting high refractive index cured product had a Tg of 75°C or higher and a refractive index of 1.62 or higher, demonstrating that it was possible to produce a high refractive index cured product with low viscosity, excellent moldability, and both a high refractive index and thermal stability. It was also found that the high refractive index curable compositions of Examples 2 and 3 had low viscosity, excellent moldability, and were capable of producing a high refractive index cured product with low viscosity, excellent moldability, and both a high refractive index and thermal stability.

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; 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. 2. The high refractive index curable composition according to claim 1, which has a viscosity at 25°C of 1000 mPa or less.

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

4. The high refractive index curable composition according to claim 1 , wherein the content of the polyfunctional (meth)acrylate compound (A) is from 1% by mass to 70% by mass.

5. The high refractive index curable composition according to claim 1 , wherein the content of the monofunctional (meth)acrylate compound (B) is 30% by mass or more and 99% by mass or less.

6. The high refractive index curable composition according to claim 1 , wherein the substituent a and the substituent c in the general formula (1) are different from each other.

7. A high refractive index cured product obtained by photocuring the high refractive index curable composition according to any one of claims 1 to 6.

8. 8. The high refractive index cured product according to claim 7, which has a refractive index n of 1.60 or more at a wavelength of 636 nm.

9. 8. The high refractive index cured product according to claim 7, which has a glass transition temperature of 60°C or higher as measured by differential scanning calorimetry.

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