Diepoxy Compound, Curable Composition, Cured Product, and Optical Member

Abstract

The present invention provides: a diepoxy compound from which a cured product having a low water absorption rate is obtained; a curable composition using said diepoxy compound; a cured product; and an optical member.　One mode of the present invention pertains to a diepoxy compound represented by formula 1 and a diepoxy compound represented by formula 2.　In formulae 1 and 2, at least one R1 is an epoxy group and the remaining R1s are each independently a hydrogen atom or a linear or branched-chain alkyl group having 1-10 carbon atoms. The same applies for R2, R3, and R4.

Description

Technical Field

[0001] The present invention relates to a diepoxy compound, a curable composition, a cured product, and an optical member.

Background Art

[0002] Epoxy compounds are used in a wide range of applications. A cured product obtained by polymerizing an epoxy compound is excellent in adhesiveness, heat resistance, mechanical properties, electrical properties, and light resistance, and is easy to form. Among epoxy compounds, diepoxy compounds are expected to be applied to optoelectronic fields such as electronic members, optical members, optical semiconductor encapsulants, adhesives for optical members, and stereolithography materials (for example, Patent Documents 1 to 4, Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Documents 1 and 2 disclose, as diepoxy compounds, for example, diepoxy compounds having a cyclohexane skeleton such as 3’,4’-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 2,2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane. However, since the diepoxy compounds of Patent Documents 1 and 2 contain an ester bond or an ether bond, the cured product is liable to be hydrolyzed under high temperature and high humidity. Further, since the water absorption rate is high, the cured product is liable to be deformed by swelling, and the properties required for optical parts, electronic members, etc. may deteriorate.

[0006] Diepoxy compounds that do not contain an ester bond or an ether bond are also known. For example, Patent Document 3 discloses a diepoxy compound in which two 3,4-epoxycyclohexyl groups are bonded by -CH2- or -C(CH3)2-. Non-Patent Document 1 discloses a diepoxy compound in which two cyclohexyl groups having a glycidyl group bonded to the 4-position carbon atom are bonded by -C(CH3)2-. Patent Document 4 discloses a diepoxy compound in which two cyclohexyl groups having an epoxy group bonded to the 4-position carbon atom are bonded by -CH2CH2CH(CH3)-. However, it may be difficult to sufficiently reduce the water absorption rate even in cured products using these diepoxy compounds.

[0007] One aspect of the present invention provides a diepoxy compound capable of obtaining a cured product having a low water absorption rate, a curable composition using the diepoxy compound, a cured product, and an optical member.

Means for Solving the Problems

[0008] The present invention has the following aspects. [1] A diepoxy compound represented by the following Formula 1.

[0009]

Chemical formula

[0010] In Formula 1, any one of R 1 is an epoxy group, and the remaining Rs 1 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Any one of R 2 is an epoxy group, and the remaining Rs 2 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. [2] The diepoxy compound according to [1], which is a compound represented by the following Formula 11.

[0011]

Chemical formula

[0012] In Formula 11, R 1 and R 2 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. [3] The diepoxy compound according to [1] or [2], wherein the Rs 1 and R 2 that are not epoxy groups are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. [4] The diepoxy compound according to [1] or [2], wherein the Rs 1 and R 2 that are not epoxy groups are all hydrogen atoms. [5] A diepoxy compound represented by the following Formula 2.

[0013]

Chemical formula

[0014] In Formula 2, any one of R 3 is an epoxy group, and the remaining Rs 3 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Any one of R 4 is an epoxy group, and the remaining Rs 4 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. R5 and R 6 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. R 5 and R 6 may be bonded to each other to form a ring structure. The diepoxy compound of [5], which is a compound represented by the following formula 21.

[0015]

Chemical formula

[0016] In formula 21, R 3 and R 4 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. [7] R that is not an epoxy group 3 and R 4 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms; R 5 and R 6 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, the diepoxy compound of [5] or [6]. [8] R that is not an epoxy group 3 and R 4 are all hydrogen atoms, the diepoxy compound of any one of [5] to [7]. [9] R 5 and R 6 are methyl groups, the diepoxy compound of [8].

[10] A curable composition containing any one of the diepoxy compounds of [1] to [9] and an initiator.

[11] The cured product of the curable composition of

[10] .

[12] The cured product of

[11] , having a water absorption rate of 0.45% or less when exposed to distilled water at 23°C for 24 hours.

[13] An optical member made of the cured product of

[11] or

[12] .

Advantages of the Invention

[0017] According to one aspect of the present invention, there are provided a diepoxy compound capable of obtaining a cured product having a low water absorption rate, a curable composition using the diepoxy compound, a cured product, and an optical member.

Mode for Carrying Out the Invention

[0018] The water absorption rate is measured by the method described in the examples. The numerical range represented by “~” means a numerical range including the numerical values before and after ~ as the lower limit value and the upper limit value. The numerical ranges of the contents, various physical property values, and property values disclosed in this specification can be combined arbitrarily with their lower limit values and upper limit values to form new numerical ranges.

[0019] [Diepoxy Compound] The diepoxy compound of the first aspect of the present invention is a compound represented by the following formula 1 (hereinafter, also referred to as “Compound A”).

[0020]

Chemical formula

[0021] In formula 1, any one of R 1 is an epoxy group, and the remaining R 1 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Also, any one of R 2 is an epoxy group, and the remaining R 2 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms.

[0022] R 1 The epoxy group of may be bonded to any carbon atom in the cyclohexane ring to which a plurality of R 1 are bonded. From the viewpoint of production simplicity, the epoxy group of R 1 is preferably bonded to the 4-position carbon atom of the cyclohexane ring to which a plurality of R 1 are bonded.

[0023] A plurality of R that are not epoxy groups1 may be the same group or different groups. R that is not an epoxy group 1 From the viewpoint of water absorption rate, a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms is preferable, and a hydrogen atom is particularly preferable.

[0024] R 2 The epoxy group of R 2 may be bonded to any carbon atom in the cyclohexane ring to which a plurality of Rs are bonded. From the viewpoint of production simplicity, the epoxy group of R 2 is preferably bonded to the 4-position carbon atom of the cyclohexane ring to which a plurality of Rs are bonded. 2

[0025] A plurality of Rs that are not epoxy groups 2 may be the same group or different groups. R that is not an epoxy group 2 may be the same group as R that is not an epoxy group 1 or a different group. R that is not an epoxy group 2 From the viewpoint of water absorption rate, a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms is preferable, and a hydrogen atom is particularly preferable.

[0026] From the viewpoint of water absorption rate, as compound A, a compound represented by the following formula 11 (hereinafter, also referred to as "compound A1") is preferable.

[0027]

Chemical formula

[0028] In formula 11, R 1 and R 2 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms.

[0029] In the above formula 11, preferable embodiments of R 1 and R 2 are the same as those of R that is not an epoxy group in the above formula 1 1 and R 2 ​is the same as the preferred embodiment. From the viewpoint of ease of production, as compound A1, in formula 11 above, R 1 and R 2 are all hydrogen atoms, that is, the compound represented by the following formula 12 (hereinafter also referred to as "compound A1-1") is particularly preferred.

[0030]

Chemical formula

[0031] The method for synthesizing compound A is not particularly limited. Compound A can be synthesized by appropriately combining various reactions. For example, when a compound in which two epoxy groups in compound A are substituted with hydroxy groups is used as a starting material, the starting material is reacted with a silylating agent (such as tert-butyldimethylchlorosilane) to substitute the two hydroxy groups with silyl groups to obtain a disilyl compound. Next, the disilyl compound is reacted with a halide (such as boron tribromide), and the two silyl groups are substituted with halogen atoms by desilylation and halogenation to obtain a dihalogen compound. Next, in the presence of a copper catalyst (such as CuCl2), the dihalogen compound and vinylmagnesium bromide are subjected to a cross-coupling reaction, and then reacted with a peroxide (such as metachloroperbenzoic acid) to epoxidize the vinyl group, whereby compound A is obtained.

[0032] The solvent used for the synthesis of compound A may be appropriately selected as long as it does not adversely affect each reaction. For example, dimethylformamide, dichloromethane, tetrahydrofuran, halogenated hydrocarbons (such as dichloromethane), ethers (such as diethyl ether, tetrahydrofuran), aromatic hydrocarbons (such as benzene, toluene), aliphatic hydrocarbons (such as hexane, pentane), amide solvents (such as N,N-dimethylformamide, N-methylpyrrolidone) can be exemplified.

[0033] The diepoxy compound of the second aspect of the present invention is a compound represented by the following formula 2 (hereinafter also referred to as "compound B").

[0034] [Chemical]

[0035] In Formula 2, any one of the Rs 3 is an epoxy group, and the remaining Rs 3 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Also, any one of the Rs 4 is an epoxy group, and the remaining Rs 4 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. R 5 and R 6 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. R 5 and R 6 may be bonded to each other to form a ring structure.

[0036] R 3 The epoxy group of may be bonded to any carbon atom in the cyclohexane ring to which a plurality of Rs 3 are bonded. From the viewpoint of ease of production, the epoxy group of R 3 is preferably bonded to the 4-position carbon atom of the cyclohexane ring to which a plurality of Rs 3 are bonded.

[0037] The plurality of Rs that are not epoxy groups 3 may be the same group or different groups. As R that is not an epoxy group 3 from the viewpoint of water absorption rate, a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms is preferable, and a hydrogen atom is particularly preferable.

[0038] R 4 The epoxy group of may be bonded to any carbon atom in the cyclohexane ring to which a plurality of Rs 4 are bonded. From the viewpoint of ease of production, the epoxy group of R 4 is preferably bonded to the 4-position carbon atom of the cyclohexane ring to which a plurality of Rs 4 are bonded.

[0039] A plurality of Rs that are not epoxy groups 4 may be the same group or different groups. R that is not an epoxy group 4 is R that is not an epoxy group 3 may be the same group or different groups. R that is not an epoxy group 4 In terms of water absorption rate, a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms is preferable, and a hydrogen atom is particularly preferable.

[0040] R 5 and R 6 may be the same group or different groups. R 5 and R 6 When forming a ring structure, it is a cycloalkyl group. R 5 and R 6 When forming a ring structure, a cycloalkyl group having 5 to 12 carbon atoms is preferable, and a cycloalkyl group having 6 or less carbon atoms is more preferable. R 5 and R 6 The ring structure formed may be a monocyclic structure or a polycyclic structure.

[0041] R 5 and R 6 For ease of production, each is independently preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0042] In terms of water absorption rate, as compound B, a compound represented by formula 21 below (hereinafter, also referred to as "compound B1") is preferable.

[0043]

Chemical formula

[0044] In formula 21, R 3 and R 4 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. R 5 and R6 is the same as the above formula 2.

[0045] R in the above formula 21 3 ~R 6 The preferred embodiments of are the R that is not an epoxy group in the above formula 2 3 and R 4 R 5 R 6 are the same as the preferred embodiments of. As the compound B1, for example, a compound represented by the following formula 22 (hereinafter, also referred to as "compound B1-1") can be exemplified. R 5 and R 6 As the compound B1 in which and form a ring structure, for example, a compound represented by the following formula 23 and a compound represented by the following formula 24 can be exemplified.

[0046]

Chemical formula

[0047] From the viewpoint of easiness of production, as the compound B1, a compound in which all of R 3 and R 4 are hydrogen atoms, and R 5 and R 6 are methyl groups is particularly preferred.

[0048] The method for synthesizing the compound B is not particularly limited. The compound B can be synthesized by appropriately combining various reactions. For example, except using a compound in which two epoxy groups in the compound B are substituted with hydroxy groups as a starting material, the compound B can be synthesized in the same manner as the methods exemplified as the method for synthesizing the compound A.

[0049] [Curable composition] The curable composition of the present invention contains the diepoxy compound of the present invention and an initiator. Depending on the type of the initiator, a cured product can be obtained by subjecting the curable composition of the present invention to light irradiation, heating, etc. for curing.

[0050] The curable composition of the present invention may contain only one of Compound A and Compound B as the diepoxy compound, or may contain both. The Compound A contained in the curable composition may be one kind or two or more kinds. The Compound B contained in the curable composition may be one kind or two or more kinds.

[0051] The curable composition of the present invention may contain, as a resin component, other epoxy compounds, oxetane compounds, etc. other than Compound A and Compound B, as long as the effects of the present invention are not impaired. Examples of the oxetane compound include various monofunctional oxetane compounds and polyfunctional oxetane compounds. Examples of the monofunctional oxetane compound include 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane. Examples of the polyfunctional oxetane compound include 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane. Examples of other epoxy compounds include 2,2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane. Other resin components other than Compound A and Compound B contained in the curable composition may be one kind or two or more kinds.

[0052] The initiator for initiating the curing of the curable composition of the present invention is not particularly limited. For example, initiators that generate cationic species by light irradiation or heating can be exemplified. The initiator contained in the curable composition may be one kind or two or more kinds.

[0053] The initiator that generates cationic species by light irradiation is not particularly limited. For example, ultraviolet cationic polymerization initiators that generate an acid capable of cationic polymerization by irradiation with ultraviolet rays can be exemplified.

[0054] The ultraviolet cationic polymerization initiator generates an acid capable of cationic polymerization upon irradiation with ultraviolet light. For example, diazonium salt compounds, iodonium salt compounds, sulfonium salt compounds, phosphonium salt compounds, selenium salt compounds, oxonium salt compounds, ammonium salt compounds, bromine salt compounds, etc. can be exemplified.

[0055] As the anion component of the ultraviolet cationic polymerization initiator, for example, SbF6 - , PF6 - , BF4 - , AsF6 - , B(C6F5)4 - can be exemplified. From the viewpoint of curability, onium salts such as aromatic sulfonium salts containing B(C6F5)4 - , PF6 - or SbF6 - as the anion component are preferred, and onium salts such as aromatic sulfonium salts containing B(C6F5)4 - as the anion component are more preferred. The ultraviolet cationic polymerization initiator contained in the curable resin composition may be one kind or two or more kinds.

[0056] The curable composition of the present invention may further contain additives as required. Examples of the additives include coupling agents (such as silane-based coupling agents and titanium-based coupling agents), flexibility-imparting agents (such as synthetic rubbers and polyorganosiloxanes), antioxidants, defoaming agents, hydrocarbon-based waxes, inorganic fillers, etc.

[0057] The total content of Compound A and Compound B in the curable composition of the present invention is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, based on the total mass of the resin components in the curable composition. If the total content of Compound A and Compound B is equal to or higher than the lower limit value of the above range, the water absorption rate of the cured product is low, and it is difficult to deform due to swelling even in a high-temperature and high-humidity environment.

[0058] The content of the initiator in the curable composition of the present invention is preferably 0.1 to 2.0 parts by mass, more preferably 0.2 to 1.0 parts by mass, based on 100 parts by mass of the resin component in the curable composition. If the content of the initiator is equal to or higher than the lower limit value of the above range, the curability is excellent. If the content of the initiator is equal to or lower than the upper limit value of the above range, it is easy to suppress the coloring of the cured product.

[0059] [Cured product] The cured product of the present invention is the cured product of the curable composition of the present invention. The shape and dimensions of the cured product are not particularly limited and can be appropriately set according to the use. The use of the cured product of the present invention is not particularly limited. For example, electronic members, optical members, optical semiconductor encapsulants, adhesives for optical members, and stereolithography materials can be exemplified. Among them, the cured product of the present invention is useful as an optical member because of its low water absorption rate and difficulty in deformation.

[0060] When the cured product of the present invention is exposed to distilled water at 23°C for 24 hours, the water absorption rate is preferably 0.45% or less, more preferably 0.40% or less, and even more preferably 0.35% or less. If the water absorption rate is equal to or lower than the above upper limit value, it is difficult to deform due to swelling even in a high-temperature and high-humidity environment, and it is possible to suppress a decrease in the characteristics required for optical components, electronic components, etc. The lower the water absorption rate of the cured product, the better, and the substantial lower limit is about 0.10%.

[0061] As described above, in the present invention, by using Compound A and Compound B which are diepoxy compounds, a cured product with a low water absorption rate can be obtained. Therefore, the cured product is difficult to deform due to swelling, and the characteristics required for optical components, electronic members, etc. are less likely to deteriorate. In addition, since Compound A and Compound B do not contain an ester bond or an ether bond, hydrolysis does not occur even under high temperature and high humidity, and the durability is excellent. [Examples]

[0062] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the following description. Examples 1 and 2 are examples. Examples 3 to 6 are comparative examples.

[0063] [Synthesis Example 1] Compound B1-1 was synthesized by the following procedure. The reaction represented by the following Formula 3 was carried out. 2,2-Bis(4-hydroxycyclohexyl)propane (30 g, 128.9 mmol) was dissolved in dimethylformamide (DMF, 500 mL), and further imidazole (38.3 g, 562 mmol) and tert-butyldimethylchlorosilane (TBDMSCl, 84.7 g, 562 mmol) were added at 0 °C, followed by stirring overnight at room temperature under a nitrogen atmosphere. After completion of the reaction, a mixed solvent of ethyl acetate / hexane = 1 / 4 and water were added to extract the reaction product. Subsequently, it was washed twice with water, and the solvent was removed to obtain a white solid disilylated product (58.3 g). The disilylated product (42.4 g) was dissolved in dichloromethane (480 mL), and a 1 M dichloromethane solution of boron tribromide (275 mL) was added dropwise at 0 °C. After completion of the dropwise addition, the reaction was carried out overnight at room temperature. After completion of the reaction, the reaction solution was added to a saturated aqueous sodium hydrogen carbonate solution, stirred for 10 minutes, and then extracted. Subsequently, it was washed twice with water, the solvent was removed, and a transparent oily dibrominated product (30.0 g, 82.4 mmol) was isolated by flash column chromatography (5% ethyl acetate / hexane solution). The total yield of the reaction of Formula 3 was 88.3%.

[0064]

Chemical formula

[0065] Subsequently, the reaction represented by the following Formula 4 was carried out. The dibrominated product (30 g, 82.4 mmol) was dissolved in tetrahydrofuran (THF, 180 mL), and ethynylbenzene (0.93 g, 8.2 mmol) and CuCl2 (2.2 g, 16.4 mmol) were added at 0 °C. A 1 M THF solution of vinylmagnesium bromide (300 ml) was added dropwise at 0 °C under a nitrogen atmosphere. After completion of the dropwise addition, the mixture was stirred overnight at room temperature, then a 10% hydrochloric acid solution was added to terminate the reaction, and the reaction product was extracted with ethyl acetate. Subsequently, it was washed twice with water, the solvent was removed, and a transparent oily diene (15.1 g, 58.0 mmol, 70.4%) was isolated by flash column chromatography (5% ethyl acetate / hexane solution).

[0066] [Chemistry]

[0067] The reaction represented by the following formula 5 was carried out. Dien (15.1 g, 58.0 mmol) was dissolved in dichloromethane (330 ml), and metachloroperbenzoic acid (61.6 g, 232.0 mmol) was added at 0 °C, followed by stirring overnight at room temperature. The reaction solution was added to a saturated aqueous sodium sulfite solution to terminate the reaction, and the reaction product was extracted. Then, it was washed with water, the solvent was removed, and a transparent oily compound (B1-1) (4.5 g, 15.4 mmol, 26.6%) was isolated by flash column chromatography (ethyl acetate / hexane = 1 / 6 solution).

[0068] The NMR spectrum of compound (B1-1) is shown below. 1 H-NMR (400 MHz, solvent: CDCl3, reference: tetramethylsilane (TMS)) δ (ppm): 3.11 - 2.50 (m, 6H), 1.99 - 1.96 (m, 2H), 1.76 - 1.73 (m, 5H), 1.58 - 1.55 (m, 2H), 1.34 - 1.00 (m, 11H), 0.76 - 0.71 (m, 6H)

[0069] [Chemistry]

[0070] [Synthesis Example 2] Compound A1-1 was synthesized by the following procedure. The reaction represented by the following formula 6 was carried out. 4,4-Bicyclohexanol (50 g, 252.1 mmol) was dissolved in DMF (500 mL), and further imidazole (41.0 g, 602.2 mmol) and TBDMSCl (92.0 g, 610.4 mmol) were added at 0 °C, and the mixture was stirred overnight at room temperature under a nitrogen atmosphere. After completion of the reaction, a mixed solvent of ethyl acetate / hexane = 1 / 4 and water were added, and the reaction product was extracted. Then, it was washed twice with water, the solvent was removed, and a white solid disilyl compound (70.34 g) was obtained. The disilyl compound (70.34 g) was dissolved in dichloromethane (600 ml), and a 1 M dichloromethane solution of boron tribromide (400 ml) was added dropwise at 0 °C. After completion of the dropwise addition, the reaction was allowed to proceed overnight at room temperature. After completion of the reaction, the reaction solution was added to a saturated aqueous sodium hydrogen carbonate solution, stirred for 10 minutes, and then the reaction product was extracted. Then, it was washed twice with water, the solvent was removed, and a transparent oily dibromo compound (57.0 g, 177.1 mmol) was isolated by flash column chromatography (5% ethyl acetate / hexane solution). The total yield of the reaction of formula 6 was 70.2%.

[0071]

Chemical formula

[0072] The reaction represented by formula 7 was carried out. The dibromo compound (29.1 g, 90.3 mmol) was dissolved in THF (180 mL), ethynylbenzene (1.1 g, 9.0 mmol) and CuCl2 (2.4 g, 18.1 mmol) were added at 0 °C, and a 1 M THF solution of vinylmagnesium bromide (270 mL) was added dropwise at 0 °C under a nitrogen atmosphere. After completion of the dropwise addition, the mixture was stirred overnight at room temperature, then a 10% hydrochloric acid solution was added to terminate the reaction, and the reaction product was extracted with ethyl acetate. Then, it was washed twice with water, the solvent was removed, and a transparent oily diene (11.0 g, 50.6 mmol, 56.0%) was isolated by flash column chromatography (5% ethyl acetate / hexane solution).

[0073]

Chemical formula

[0074] The reaction represented by Formula 8 was carried out. The diene (21.6 g, 98.9 mmol) was dissolved in dichloromethane (400 ml), and metachloroperbenzoic acid (105.0 g, 395.6 mmol) was added at 0 °C, followed by stirring overnight at room temperature. The reaction solution was added to a saturated aqueous sodium sulfite solution to terminate the reaction, and the reaction product was extracted. Subsequently, it was washed with water, the solvent was removed, and a transparent oily compound A1-1 (5.5 g, 21.8 mmol, 22.0%) was isolated by flash column chromatography (ethyl acetate / hexane = 1 / 6 solution).

[0075] The NMR spectrum of compound (A1-1) is shown below. 1 H-NMR (400 MHz, solvent: CDCl3, reference: TMS) δ (ppm): 2.96 - 2.46 (m, 6H), 1.94 - 0.88 (m, 20H)

[0076]

Chemical formula

[0077] [Example 1] To 100 parts by mass of the compound B1-1 obtained in Synthesis Example 1, 0.5 part by mass of an ultraviolet cationic polymerization initiator (Irgacure 290, manufactured by BASF) was added to prepare a curable composition. Two disk-shaped glass substrates with a release treatment were prepared. On one glass substrate, the other glass substrate was placed in parallel so that the interval between the glass substrates was 1.0 mm. The curable composition was poured between the two glass substrates so as not to contain bubbles. Subsequently, the curable composition sandwiched between the two glass substrates was irradiated with ultraviolet light (using an LED lamp with a wavelength of 365 nm) at an exposure dose of 4500 mJ / cm 2 and then allowed to stand at room temperature for 15 minutes. A disk-shaped cured product with a thickness of 1.0 mm and a weight of about 0.5 g was released from the two glass substrates, and the released cured product was heat-treated under the conditions of 180 °C for 3 hours in a nitrogen atmosphere to obtain a sample for evaluation.

[0078] [Example 2] An evaluation sample was obtained in the same manner as in Example 1, except that Compound A1-1 obtained in Synthesis Example 2 was used instead of Compound B1-1. Specifically, a curable composition was prepared using Compound A1-1, and then a cured product was produced under the same conditions as in Example 1 to obtain an evaluation sample.

[0079] [Example 3] A curable composition was prepared in the same manner as in Example 1, except that 3’,4’-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (CEL-2021P, manufactured by Daicel Corporation) was used instead of Compound B1-1. Using the said curable composition, and after irradiating ultraviolet rays with an LED lamp having a wavelength of 365 nm at an exposure dose of 9000 mJ / cm 2 A cured product was produced under the same conditions as in Example 1 to obtain an evaluation sample, except that after irradiation, it was heated at 60 °C for 5 minutes and then at 80 °C for 5 minutes instead of standing at room temperature.

[0080] [Example 4] A curable composition was prepared in the same manner as in Example 1, except that 2,2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane (YX-8000, manufactured by Mitsubishi Chemical Corporation) was used instead of Compound B1-1. Using the said curable composition, a cured product was produced under the same conditions as in Example 1 to obtain an evaluation sample, except that it was not allowed to stand at room temperature after ultraviolet irradiation.

[0081] [Example 5] An evaluation sample was obtained in the same manner as in Example 4, except that Compound C-1 represented by the following formula C-1 was used instead of Compound B1-1. Specifically, a curable composition was prepared using Compound C-1, and then a cured product was produced under the same conditions as in Example 4 to obtain an evaluation sample.

[0082] [Chemical formula]

[0083] [Example 6] An evaluation sample was obtained in the same manner as in Example 4, except that the compound C-2 represented by the following formula C-2 was used instead of the compound B1-1. Specifically, a curable composition was prepared using the compound C-2, and then a cured product was produced under the same conditions as in Example 4 to obtain an evaluation sample.

[0084] [Chemical formula]

[0085] [Water absorption rate] The evaluation samples of each example were dried under reduced pressure, and the evaluation samples after drying under reduced pressure were weighed, and the weighed value was designated as W. A Further, the evaluation sample was exposed to distilled water at 23 °C for 24 hours, and then the evaluation sample was weighed again, and the weighed value was designated as W. B Using these weighed values, the water absorption rate was calculated from the following formula. The water absorption rate was measured for 3 to 5 evaluation samples under the same conditions, and the average value thereof was taken as the water absorption rate of the cured product of each example. The evaluation results of each example are shown in Table 1. Water absorption rate (%) = ((W B - W A ) / W A ) × 100

[0086] [Table 1]

[0087] As shown in Table 1, the cured products of Examples 1 and 2 had a lower water absorption rate than the cured products of Examples 3 to 6. [Industrial applicability]

[0088] According to one aspect of the present invention, there are provided a diepoxy compound capable of obtaining a cured product having a low water absorption rate, a curable composition using the diepoxy compound, a cured product, and an optical member.

[0089] Further, this application claims the priority based on Japanese Patent Application No. 2020-210133 filed on December 18, 2020, and incorporates the entire contents of the Japanese application herein by reference.

Claims

1. A diepoxy compound represented by the following formula 1. 【Chemical 1】 In Formula 1, any one of Rs １ is an epoxy group, and the remaining Rs １ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Any one of Rs ２ is an epoxy group, and the remaining Rs ２ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms.

2. The diepoxy compound according to Claim 1, which is a compound represented by the following formula 11. 【Chemical Formula 2】 In Formula 11, R １ and R ２ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms.

3. R which is not an epoxy group １ and R ２ is each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, the diepoxy compound according to claim 1 or 2.

4. R which is not an epoxy group １ and R ２ are all hydrogen atoms, the diepoxy compound according to claim 1 or 2.

5. A diepoxy compound represented by the following formula 2. [Chemical 3] In Formula 2, any one of Rs ３ is an epoxy group, and the remaining Rs ３ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Any one of Rs ４ is an epoxy group, and the remaining Rs ４ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Rs ５ and Rs ６ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. Rs ５ and Rs ６ may be bonded to each other to form a ring structure.

6. The diepoxy compound according to Claim 5, which is a compound represented by the following formula 21. 【Chemical Formula 4】 In Formula 21, R ３ and R ４ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms.

7. R that is not an epoxy group ３ and R ４ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, R ５ and R ６ is each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, the diepoxy compound according to claim 5 or 6.

8. R that is not an epoxy group ３ and R ４ The diepoxy compound according to any one of claims 5 to 7, wherein all are hydrogen atoms.

9. R ５ and R ６ The diepoxy compound according to claim 8, wherein R and R are methyl groups.

10. A curable composition comprising the diepoxy compound according to any one of Claims 1 to 9 and an initiator.

11. A cured product of the curable composition according to Claim 10.

12. The cured product according to Claim 11, having a water absorption rate of 0.45% or less when exposed to distilled water at 23°C for 24 hours.

13. An optical member made of the cured product according to Claim 11 or 12.

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