Isophthalic acid compound and use of the same

Abstract

To provide a new isophthalic acid compound, a crosslinking agent for an epoxy resin containing the isophthalic acid compound, a resin composition containing the crosslinking agent for the epoxy resin and a curd product thereof.SOLUTION: An isophthalic acid compound is represented by the chemical formulae (I-1) to (I-5).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a novel isophthalic acid compound, a curing agent for epoxy resin containing the isophthalic acid compound, a resin composition containing the curing agent for epoxy resin, and a cured product thereof.

Background Art

[0002] Epoxy resin compositions can easily obtain cured products having excellent electrical properties, mechanical properties, and thermal properties by combining various epoxy resins (referring to epoxy compounds before curing) with a curing agent, and thus are adopted in many fields. Further, usually, in an epoxy resin composition, an epoxy resin having an epoxy group in the molecule, a curing agent, and a curing accelerator are used for the purpose of accelerating curing as necessary.

[0003] As conventionally known curing agents for epoxy resins, acidic compounds such as dibasic acids, acid anhydrides, and phenol compounds, and basic compounds such as amines, ureas, and imidazoles are properly used according to the required properties of the cured product.

[0004] For example, Patent Document 1 proposes a one-component epoxy resin composition containing a dibasic acid as a curing agent, and discloses isophthalic acid, phthalic acid, etc. as the dibasic acid. However, epoxy resin compositions containing these dibasic acids have a still room for improvement in terms of storage stability because they cure rapidly.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a novel isophthalic acid compound and its use. Specifically, an object is to provide a novel isophthalic acid compound, a curing agent for an epoxy resin containing the isophthalic acid compound, a resin composition containing the curing agent for an epoxy resin, and a cured product thereof.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventors have found that an isophthalic acid compound having 2 to 3 iodine atoms in the molecule is a novel compound, and an epoxy resin composition containing the compound has good storage stability and good curability (relatively long gel time), and thus have completed the present invention. That is, the first invention is an isophthalic acid compound represented by chemical formulas (I-1) to (I-5).

[0008]

Chemical formula

[0009] The second invention is a curing agent for an epoxy resin containing the isophthalic acid compound of the first invention. The third invention is an epoxy resin composition containing the curing agent for an epoxy resin of the second invention and an epoxy resin. The fourth invention is an epoxy resin composition of the third invention containing a curing accelerator. The fifth invention is a cured product obtained by curing the resin composition of any one of the third to fourth inventions.

Effects of the Invention

[0010] Since the isophthalic acid compound of the present invention has two carboxyl groups in the molecule, it is expected to be used as a curing agent for epoxy resins. Moreover, the isophthalic acid compound of the present invention has 2 to 3 iodine atoms in the molecule. When used as a curing agent for an epoxy resin composition, it exhibits better storage stability and curability compared to the case of using a conventional curing agent, and is expected to provide a cured product having excellent heat resistance and electrical properties.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail. <Isophthalic Acid Compound> The present invention relates to an isophthalic acid compound represented by chemical formulas (I-1) to (I-5) (hereinafter, sometimes referred to as "the isophthalic acid compound of the present invention").

[0012]

Chemical Formula

[0013] Examples of the method for synthesizing the isophthalic acid compound of the present invention include the methods of synthesis methods (1) and (2).

[0014] <Synthesis Method (1)> The isophthalic acid compound of the present invention can be synthesized by iodinating the amino group of an isophthalic acid compound having an amino group and hydrogenating the amino group of an iodo isophthalic acid compound having an amino group (Sandmeyer reaction). Specifically, it can be synthesized by diazotizing the amino group of an isophthalic acid compound having an amino group with a nitrous acid compound and reacting the resulting product with an iodinating agent, and by diazotizing the amino group of an iodo isophthalic acid compound having an amino group with a nitrous acid compound and reacting the resulting product with hypophosphorous acid.

[0015] Examples of the isophthalic acid compound having an amino group include compounds represented by chemical formulas (II-1-1) to chemical formula (II-5-2).

[0016]

Chemical Formula

[0017] These compounds can be used by purchasing commercially available reagents, and can also be synthesized by introducing an iodine atom into an isophthalic acid compound having an amino group, oxidizing the methyl group of an m-xylene compound having an amino group and an iodine atom, or introducing an amino group into an isophthalic acid compound having an iodine atom.

[0018] Examples of the nitrous acid compounds include sodium nitrite, potassium nitrite, methyl nitrite, ethyl nitrite, n-propyl nitrite, isopropyl nitrite, isobutyl nitrite, n-butyl nitrite, tert-butyl nitrite, n-pentyl nitrite, isoamyl nitrite, and the like. These nitrous acid compounds can be used by purchasing commercially available reagents.

[0019] The amount of the nitrous acid compound used is in the range of 1 to 100 times the molar amount of the isophthalic acid compound having an amino group, and preferably in the range of 1 to 2 times the molar amount.

[0020] Examples of the iodinating agent include potassium iodide, sodium iodide, copper(I) iodide, and the like. These iodinating agents can be used by purchasing commercially available reagents.

[0021] The amount of the iodinating agent used is preferably in the range of 1 to 100 times the molar amount of the isophthalic acid compound having an amino group, and more preferably in the range of 1 to 10 times the molar amount.

[0022] In carrying out this reaction, if necessary, the reaction solvent (i) may be appropriately used.

[0023] The reaction solvent (i) is not particularly limited as long as it does not inhibit the reaction. For example, acetonitrile; pyridine; water; alcohols such as methanol, ethanol, and isopropyl alcohol; aliphatic hydrocarbons such as hexane and heptane; esters such as ethyl acetate and butyl acetate; aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, chlorotrifluoromethane, dichloroethane, chlorobenzene, and dichlorobenzene; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, dimethoxyethane, and diethylene glycol dimethyl ether; amides such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and hexamethylphosphoramide; sulfoxides such as dimethyl sulfoxide, etc. can be mentioned. This reaction solvent (i) is used alone or in combination of two or more.

[0024] In this reaction, the reaction temperature is preferably set in the range of -30 to 150°C. Also, the reaction time is appropriately set according to the set reaction temperature, but it is preferably set in the range of 1 to 48 hours.

[0025] After completion of this reaction, the isophthalic acid compound of the present invention, which is the target product, can be taken out from the obtained reaction solution by means such as concentration of the reaction solution by distilling off the reaction solvent or solvent extraction method. Furthermore, if necessary, it can be purified by means such as washing with water or the like, activated carbon treatment, silica gel chromatography, recrystallization, etc.

[0026] <Synthesis method (2)> The isophthalic acid compound of the present invention can be synthesized by oxidizing the methyl group of the m-xylene compound having an iodine atom. Specifically, it can be synthesized by oxidizing the methyl group of the m-xylene compound having an iodine atom with potassium permanganate.

[0027] Examples of the m-xylene compound having an iodine atom include m-xylene compounds having an iodine atom represented by Chemical Formula (III-1) to Chemical Formula (III-5).

[0028]

Chem.

[0029] These compounds can be purchased as commercially available reagents and used, or can be synthesized by introducing an iodine atom into an m-xylene compound.

[0030] The amount of potassium permanganate used is in the range of 1 to 100 times the molar amount, preferably in the range of 2 to 10 times the molar amount, relative to the amount of the m-xylene compound having an iodine atom.

[0031] In carrying out this reaction, if necessary, a reaction solvent (i) may be appropriately used.

[0032] The reaction solvent (i) is not particularly limited as long as it does not inhibit the reaction, and examples thereof include acetonitrile, pyridine, water, alcohols such as methanol, ethanol, and isopropyl alcohol, aliphatic hydrocarbons such as hexane and heptane, esters such as ethyl acetate and butyl acetate, aromatic hydrocarbons such as benzene, toluene, and xylene, halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, chlorotrifluoromethane, dichloroethane, chlorobenzene, and dichlorobenzene, ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, dimethoxyethane, and diethylene glycol dimethyl ether, amides such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and hexamethylphosphoramide, and sulfoxides such as dimethyl sulfoxide. This reaction solvent (i) is used alone or in combination of two or more.

[0033] In this reaction, the reaction temperature is preferably set in the range of -10 to 150°C. Also, the reaction time is appropriately set according to the set reaction temperature, but it is preferably set in the range of 1 to 200 hours.

[0034] After completion of this reaction, the isophthalic acid compound of the present invention, which is the target product, can be taken out from the obtained reaction solution by means such as concentration of the reaction solution by distilling off the reaction solvent or solvent extraction method. Furthermore, if necessary, it can be purified by means such as washing with water or the like, activated carbon treatment, silica gel chromatography, recrystallization, etc.

[0035] When the isophthalic acid compound of the present invention is used as a curing agent for an epoxy resin, the epoxy resin having an epoxy group in the molecule and the isophthalic acid compound can be blended in the range of an equivalent ratio of epoxy group / carboxyl group of 1 to 15. Also, if necessary, a conventionally known curing accelerator can be used in combination in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the epoxy resin.

[0036] The epoxy resin used in the present invention is not particularly limited as long as it has an epoxy group in the molecule. Typical epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins such as phenol novolac type epoxy resins and cresol novolac type epoxy resins, alicyclic epoxy resins, cyclic alicyclic epoxy resins such as 3′,4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, nitrogen-containing cyclic epoxy resins such as triglycidyl isocyanurate and hydantoin type epoxy resins, hydrogenated bisphenol A type epoxy resins, aliphatic epoxy resins, glycidyl ether type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, dicyclo ring type epoxy resins, naphthalene type epoxy resins, halogenated epoxy resins, and epoxy-modified organopolysiloxane compounds obtained by hydrosilylation addition reaction of an organic compound having a carbon-carbon double bond and a glycidyl group with a silicon compound having an SiH group (for example, epoxy-modified organopolysiloxane compounds disclosed in JP-A-2004-99751 and JP-A-2006-282988), but are not limited thereto. These epoxy resins may be used alone or in combination of two or more.

[0037] In addition, as conventionally known curing accelerators, amine compounds such as 1,8-diazabicyclo[5.4.0]-7-undecene, diethylenetriamine, triethylenetetramine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, organic phosphine compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, phosphonium compounds such as tetrabutylphosphonium bromide, tetrabutylphosphonium diethyl phosphorodithioate, tetraphenylborate salts such as tetraphenylphosphonium·tetraphenylborate, 2-methyl-4-methylimidazole·tetraphenylborate, N-methylmorpholine·tetraphenylborate, and aliphatic acid metal salts such as lead acetate, tin octylate, cobalt hexanoate, etc. can be mentioned.

[0038] In the epoxy resin composition of the present invention, various additives such as diluents, flexibility-imparting agents, silane coupling agents, antifoaming agents, leveling agents, fillers, pigments, dyes, etc. can be added as necessary.

[0039] The isophthalic acid compound of the present invention is useful as a curing agent for epoxy resin compositions for paints, encapsulants, adhesives, resist inks, etc. for printed wiring boards and electronic parts, as well as for woodworking paints, coating agents for protecting the surfaces of optical fibers, plastics, and cans, epoxy resin compositions for ball grid array semiconductor encapsulation, epoxy resin compositions for optical semiconductor element encapsulation, epoxy resin compositions for semiconductor encapsulation used as underfill, and epoxy resin compositions for forming a resist underlayer film for lithography.

Examples

[0040] Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited thereto. The main raw materials used in the examples are as follows.

[0041] · 2-Aminoisophthalic acid (manufactured by Fujifilm Wako Pure Chemical Corporation) · 5-Aminoisophthalic acid (manufactured by Fujifilm Wako Pure Chemical Corporation) · 2,4-Diiodo-3,5-dimethylbenzenamine (synthesized according to the method described in Bulletin of the Chemical Society of Japan (1988), 61(2), 600 - 602.) · 2-Amino-5-iodoisophthalic acid (synthesized by the method of Synthesis Example 1. Refer to Chemical Formula (II-1-1).) · 5-Amino-4-iodoisophthalic acid (synthesized by the method of Synthesis Example 2. Refer to Chemical Formula (II-2-1).) · 1,5-Diiodo-2,4-dimethylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd., refer to Chemical Formula (III-3).) · 1,2,4-Triiodo-3,5-dimethylbenzene (synthesized by the method of Synthesis Example 3. Refer to Chemical Formula (III-4).) · Iodine monochloride (manufactured by Fujifilm Wako Pure Chemical Corporation) · Sodium nitrite (manufactured by Fujifilm Wako Pure Chemical Corporation) · Sodium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation) · Potassium permanganate (manufactured by Fujifilm Wako Pure Chemical Corporation)

[0042] The main raw materials and the like used in the preparation of the resin composition are as follows. (A) Epoxy resin · Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: "jER828", epoxy equivalent 189) (B) Curing agent · 2-Iodoisophthalic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) (C) Curing accelerator · 2-Ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Corporation, trade name "Curezol 2E4MZ", hereinafter referred to as "2E4MZ".)

[0043] [Synthesis Example 1] <Synthesis of 2-Amino-5-iodoisophthalic Acid (Chemical Formula (II-1-1))> A 200 mL flask was charged with 10.90 g (60 mmol) of 2-aminoisophthalic acid and 70 mL of acetic acid. While stirring at room temperature, a mixture of 9.79 g (60 mmol) of iodine monochloride and 17 mL of acetic acid was added dropwise. Subsequently, the mixture was stirred at 50 °C for 4 hours. After filtering the obtained reaction solution, 110 g of methanol and 150 g of ion-exchanged water were added to the obtained solid, and the mixture was stirred at 50 °C for 2 hours. This was filtered and dried to obtain 16.62 g of a pale yellow solid (yield: 90%).

[0044] The obtained pale yellow solid 1 1H-NMR spectral data was as follows. · 1 1H-NMR (CDCl 3 ) δ: 8.19 (s, 2H). From this spectral data, the obtained pale yellow solid was identified as the title compound (2-amino-5-iodoisophthalic acid) represented by Chemical Formula (II-1-1).

[0045] [Synthesis Example 2] <Synthesis of 5-Amino-4-iodoisophthalic Acid (Chemical Formula (II-2-1))> A 1000 mL flask was charged with 400 g of ion-exchanged water, 103.2 g (1.00 mol) of 95% sulfuric acid, 160 g (1.58 mol) of 36% hydrochloric acid, 36.3 g (0.20 mol) of 5-aminoisophthalic acid, and 32.4 g (0.20 mol) of iodine monochloride, and the mixture was stirred at 70 °C for 100 hours. After quenching with a 35% aqueous sodium bisulfite solution, 850 g of a 20% aqueous sodium hydroxide solution was added and stirred. After removing insoluble matters by filtration, chloroform was added to the filtrate and separated by liquid separation. By concentrating the organic layer, 3.88 g of a pale yellow solid was obtained (yield 6%).

[0046] The obtained pale yellow solid 1 1H-NMR spectral data was as follows. · 1 1H-NMR (CDCl 3) δ: 7.41 (d, 1H), 7.21 (d, 1H). From this spectral data, the obtained pale yellow solid was identified as the title compound (5-amino-4-iodoisophthalic acid) represented by Chemical Formula (II-2-1).

[0047] [Synthesis Example 3] [Synthesis of 1,2,4-triiodo-3,5-dimethylbenzene (Chemical Formula (III-4))] Into a 200 mL flask, 9.32 g (25 mmol) of 2,4-diiodo-3,5-dimethylbenzeneamine, 27.0 g of ion-exchanged water, 31.3 g of acetonitrile, and 5.16 g (50 mmol) of 95% sulfuric acid were charged. After purging with nitrogen, while stirring at -10°C, 6.47 g (38 mmol) of a 40% aqueous sodium nitrite solution was added dropwise. After stirring at -10°C for 1 hour, while stirring at -10°C, 13.62 g (50 mmol) of a 55% aqueous sodium iodide solution was added dropwise at -10°C, and stirring was continued for another 12 hours. After quenching with a 35% aqueous sodium bisulfite solution, filtration was carried out. 25 g of ion-exchanged water was added to the filtrate for reslurrying, and the filtrate was dried to obtain 8.44 g of a white solid (yield: 70%).

[0048] The 1 1H-NMR spectral data of the obtained white solid was as follows. · 1 1H-NMR (DMSO-d 6 ) δ: 7.78 (s, 1H), 2.99 (s, 3H), 2.32 (s, 3H). From this spectral data, the obtained white solid was identified as the title compound (1,2,4-triiodo-3,5-dimethylbenzene) represented by Chemical Formula (III-4).

[0049] [Example 1] [Synthesis of 2,5-diiodoisophthalic acid (Chemical Formula (I-1))]

[0050] To a 100 mL flask, 3.70 g (12 mmol) of 2-amino-5-iodoisophthalic acid, 5.15 g of ion-exchanged water, 6.02 g of acetonitrile, and 2.48 g (24 mmol) of 95% sulfuric acid were charged. After purging with nitrogen, while stirring at -10 °C, 3.13 g (18 mmol) of a 40% aqueous sodium nitrite solution was added dropwise. After stirring at -10 °C for 1 hour, while stirring at -10 °C, 6.62 g (24 mmol) of a 53% aqueous sodium iodide solution was added dropwise, and stirring was continued for another 12 hours. After quenching with a 35% aqueous sodium bisulfite solution, filtration was performed. 25 g of ion-exchanged water was added to the filtrate for reslurrying, and the filtrate was dried to obtain 3.80 g of a white solid (yield: 76%).

[0051] The obtained white solid's 1 1H-NMR spectral data was as follows. · 1 1H-NMR (CDCl 3 ) δ: 7.88 (s, 2H). From this spectral data, the obtained white solid was identified as the title compound (2,5-diiodoisophthalic acid) represented by chemical formula (I-1).

[0052] [Example 2] [Synthesis of 4,5-diiodoisophthalic acid (chemical formula (I-2))] To a 100 mL flask, 3.68 g (12 mmol) of 5-amino-4-iodoisophthalic acid, 5.15 g of ion-exchanged water, 6.02 g of acetonitrile, and 2.48 g (24 mmol) of 95% sulfuric acid were charged. After purging with nitrogen, while stirring at -10 °C, 3.13 g (18 mmol) of a 40% aqueous sodium nitrite solution was added dropwise. After stirring at -10 °C for 1 hour, while stirring at -10 °C, 6.62 g (24 mmol) of a 53% aqueous sodium iodide solution was added dropwise, and stirring was continued for another 12 hours. After quenching with a 35% aqueous sodium bisulfite solution, filtration was performed. 25 g of ion-exchanged water was added to the filtrate for reslurrying, and the filtrate was dried to obtain 4.26 g of a white solid (yield: 85%).

[0053] The obtained white solid's 1The 1H-NMR spectral data were as follows. · 1 1H-NMR(CDCl 3 ) δ: 8.41 (d, 1H), 7.87 (d, 1H). From this spectral data, the obtained white solid was identified as the title compound (4,5-diiodoisophthalic acid) represented by Chemical Formula (I-2).

[0054] Example 3 Synthesis of 4,6-Diiodoisophthalic Acid (Chemical Formula (I-3)) A 100 mL flask was charged with 1.83 g (5.00 mmol) of 1,5-diiodo-2,4-dimethylbenzene and 10.0 g of pyridine. While stirring at 95 °C, 7.90 g (50.0 mmol) of potassium permanganate was added portionwise in 10 portions at 1-hour intervals. After the addition, the mixture was stirred at 95 °C for 150 hours. The resulting reaction solution was filtered and then washed with a 5% aqueous potassium hydroxide solution. Next, ethyl acetate was added, and after confirming that the aqueous layer was basic, liquid separation was performed, and the organic layer was removed. Ethyl acetate and hydrochloric acid were added to the aqueous layer, and after confirming that the aqueous layer was acidic, the organic layer was extracted. By concentrating the organic layer, 0.48 g of a white solid was obtained (yield 23%).

[0055] The 1H-NMR 1 spectral data of the obtained white solid were as follows. · 1 1H-NMR(CDCl 3 ) δ: 8.61 (s, 1H), 8.00 (s, 1H). From this spectral data, the obtained white solid was identified as the title compound (4,6-diiodoisophthalic acid) represented by Chemical Formula (I-3).

[0056] Example 4 Synthesis of 2,4,5-Triiodoisophthalic Acid (Chemical Formula (I-4)) Into a flask with a capacity of 200 mL, 4.84 g (10 mmol) of 1,2,4-triiodo-3,5-dimethylbenzene, 70 g of pyridine, and 25 g of ion-exchanged water were charged, and while stirring at 90 °C, 12.64 g (80 mmol) of potassium permanganate was added in portions 10 times every 1 hour. After the addition, the mixture was further stirred at 95 °C for 50 hours. The resulting reaction solution was filtered and then washed with a 5% aqueous sodium hydroxide solution. Next, ethyl acetate was added, and after confirming that the aqueous layer was basic, liquid separation was performed and the organic layer was removed. Ethyl acetate and hydrochloric acid were added to the aqueous layer, and after confirming that the aqueous layer was acidic, the organic layer was extracted. By concentrating the organic layer, 1.27 g of a white solid was obtained (yield 23%).

[0057] For the obtained white solid 1 The 1H-NMR spectral data was as follows. · 1 1H-NMR (DMSO-d 6 ) δ: 8.01 (s, 1H). From this spectral data, the obtained white solid was identified as the title compound (2,4,5-triiodoisophthalic acid) represented by the chemical formula (I-4).

[0058] [Example 5] Epoxy resin (jER828) and a curing agent (the isophthalic acid compound of Example 1) were blended at a ratio such that the equivalent ratio of epoxy group / carboxyl group was 2:1, and further 2.0 parts by weight of a curing accelerator (2E4MZ) was mixed with respect to 100 parts by weight of the epoxy resin to prepare an epoxy resin composition. For this epoxy resin composition, the gel time at 180 °C was measured by the hot plate method (JIS C-2105) to evaluate the curing performance. The results obtained were as shown in Table 1.

[0059] [Examples 6 to 8, Comparative Example 1] As a curing agent, instead of the isophthalic acid compound of Example 1, the isophthalic acid compound of Example 2 (Example 6), the isophthalic acid compound of Example 3 (Example 7), the isophthalic acid compound of Example 4 (Example 8), and 2-iodoterephthalic acid (Comparative Example 1) were used, and each epoxy resin composition was prepared in the same manner as in Example 5, and the gel time was measured to evaluate the curing performance. The obtained evaluation results are shown in Table 1.

[0060]

Table 1

[0061] From Table 1, when the isophthalic acid compound of the present invention was used as the curing agent (Examples 5 to 8), it was confirmed that the gel time was longer than when the conventional curing agent was used (Comparative Example 1), and thus the storage stability was excellent. Therefore, the isophthalic acid compound of the present invention is considered to be more suitable as a curing agent for epoxy resins than conventional curing agents.

Industrial Applicability

[0062] Since the isophthalic acid compound of the present invention has an iodine atom in the molecule, when used as a curing agent for an epoxy resin composition, it is expected to exhibit good storage stability and give a cured product having excellent heat resistance and electrical properties as compared with the case of using a conventional curing agent. Therefore, the isophthalic acid compound of the present invention is considered to be suitable as a curing agent for epoxy resins.

Claims

1. Isophthalic acid compounds represented by chemical formulas (I-1) to (I-5). 【Chemistry 1】

2. A curing agent for epoxy resins, comprising the isophthalic acid compound according to claim 1.

3. An epoxy resin composition comprising the epoxy resin curing agent according to claim 2 and an epoxy resin.

4. 4. The epoxy resin composition according to claim 3, which further comprises a curing accelerator.

5. A cured product obtained by curing the resin composition according to any one of claims 3 to 4.

Images