Epoxy resin curing agent and epoxy resin composition

Abstract

To provide a curing agent for an epoxy resin that includes a dihydrazide compound, resulting in an epoxy resin composition with enhanced curability.SOLUTION: A dihydrazide compound is combined with a carboxylic acid compound of a specific structure.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curing agent for epoxy resins and an epoxy resin composition. [Background technology]

[0002] When used as a curing agent for epoxy resins, dihydrazide compounds have the characteristic of being able to give cured products with high transparency, and are useful as curing agents for epoxy resin encapsulants and adhesives for electronic devices that require transparency, etc. However, epoxy resin compositions using dihydrazide compounds have the problem of insufficient curability, particularly at low temperatures.

[0003] Patent Document 1 discloses a technique for improving the curability of an epoxy resin composition by using a dihydrazide compound in combination with a dibasic acid. However, the curability of the epoxy resin composition disclosed in Patent Document 1 is not necessarily sufficient, and further improvement in curability is desired. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 63-81119 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a curing agent for epoxy resins containing a dihydrazide compound, which provides an epoxy resin composition with excellent curability. [Means for solving the problem]

[0006] As a result of intensive investigations aimed at solving the above problems, the present inventors have found that the curability of an epoxy resin composition can be improved by combining a dihydrazide compound with a carboxylic acid compound having a specific structure, and have thus completed the present invention. That is, the present invention includes the following aspects.

[0007] [1] (A) a dihydrazide compound; (B) an aromatic carboxylic acid or an aliphatic carboxylic acid; A hardener composition comprising: the aromatic carboxylic acid contains one or two aromatic rings each having one carboxy group and zero to two hydroxy groups; The aliphatic carboxylic acid is a linear or branched saturated aliphatic carboxylic acid containing one carboxy group and one hydroxy group. Hardener composition. [2] The curing agent composition according to [1], which contains the aromatic carboxylic acid as component (B), and the aromatic carboxylic acid has a melting point of 300°C or less. [3] The curing agent composition according to [2], wherein the aromatic carboxylic acid has a benzene ring or a naphthalene ring structure. [4] The curing agent composition according to [3], wherein the aromatic carboxylic acid is selected from the group consisting of salicylic acid, methylenedisalicylic acid, 2-hydroxy-1-naphthoic acid, 3-methylsalicylic acid, 2,5-dihydroxybenzoic acid, 3-phenylsalicylic acid, benzoic acid, and combinations thereof. [5] The curing agent composition according to [1], which contains the aliphatic carboxylic acid as component (B), and the aliphatic carboxylic acid has 2 or 3 carbon atoms. [6] The curing agent composition according to [5], wherein the aliphatic carboxylic acid is lactic acid. [7] The curing agent composition according to any one of [1] to [6] above, wherein the dihydrazide compound has a melting point of 250°C or less. [8] An epoxy resin composition comprising the curing agent composition according to any one of the above [1] to [7] and (C) an epoxy resin. [9] An epoxy resin material comprising the epoxy resin composition according to [8], wherein the epoxy resin material is selected from the group consisting of adhesives, bonding agents, conductive materials, magnetic materials, thermally conductive materials, insulating materials, sealing materials, coating materials, vibration damping / proofing materials, soundproofing materials, fillers, and paints.

[10] The epoxy resin material according to [9] above, which is an adhesive or a sealant.

[11] A cured product obtained by curing the epoxy resin composition described in [8] above.

[12] An electronic device comprising the cured product according to

[11] above. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an epoxy resin curing agent containing a dihydrazide compound, which can provide an epoxy resin composition with excellent curability. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention relates to a curing agent composition comprising (A) a dihydrazide compound and (B) an aromatic carboxylic acid or an aliphatic carboxylic acid, wherein the aromatic carboxylic acid comprises one or two aromatic rings each having one carboxy group and zero to two hydroxy groups, and the aliphatic carboxylic acid is a linear or branched saturated aliphatic carboxylic acid comprising one carboxy group and one hydroxy group.

[0010] In the present invention, by using a dihydrazide compound as a curing agent, a highly transparent cured product can be obtained. The dihydrazide compound is not particularly limited, but from the viewpoint of the curability of the epoxy resin composition, one having a melting point of 250°C or less is preferred, and from the viewpoint of the transparency of the cured product, one having a melting point of 185°C or less is more preferred, and one having a melting point of 170°C or less is even more preferred. The lower limit of the melting point of the dihydrazide compound is not particularly limited, and may be, for example, 60°C, 80°C, or 100°C.

[0011] The dihydrazide compound is preferably particulate. The particle size of the particulate dihydrazide compound is preferably 100 μm or less in terms of improving solubility and reactivity in the epoxy resin. To reduce the viscosity of the epoxy resin composition or improve dispersibility in the epoxy resin, the median diameter is preferably 0.1 μm or more, more preferably 1 to 50 μm, and even more preferably 1 to 20 μm. If the particle size is outside this range or if the particles adhere to each other to form aggregates, it is preferable to crush or disperse the particles using a three-roll mill or planetary mixer during mixing with the epoxy resin to bring the median diameter within the above range. The median diameter can be determined from the particle size distribution obtained by laser diffraction / scattering particle size distribution measurement (JIS Z 8825) on a volume basis. Examples of laser diffraction / scattering particle size distribution analyzers that can be used include the "LA-500" manufactured by Horiba, Ltd. and the "SALD-2200" manufactured by Shimadzu Corporation.

[0012] Preferred examples of the dihydrazide compound include 1,3-bis(hydrazinocarbonoethyl)-5-isopropylhydantoin, 7,11-octadecadiene-1,18-dicarbohydrazide, adipic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, etc. The dihydrazide compounds may be used singly or in combination of two or more.

[0013] When the curing agent composition is taken as 100 mass%, the dihydrazide compound is contained in the curing agent composition in an amount of preferably 80 to 99 mass%, more preferably 85 to 98.5 mass%, and even more preferably 90 to 98 mass%. If the amount of the dihydrazide compound is within the above range, when the curing agent composition is mixed with an epoxy resin to form an epoxy resin composition, the composition has a good pot life and tends to undergo a uniform curing reaction, which is preferable.

[0014] The curing agent composition of the present invention contains an aromatic carboxylic acid or an aliphatic carboxylic acid having a specific structure. The aromatic carboxylic acid or the aliphatic carboxylic acid has the function of accelerating the curing of the epoxy resin composition with the dihydrazide compound.

[0015] The aromatic carboxylic acid contains one or two aromatic rings each having one carboxy group and zero to two hydroxy groups. When the numbers of carboxy groups, hydroxy groups, and aromatic rings are within the above ranges, the reaction of the dihydrazide compound can be further accelerated. From the viewpoint of the curability of the epoxy resin composition, the aromatic carboxylic acid preferably has a melting point of 300°C or less, and from the viewpoint of the transparency of the cured product, it is more preferably 250°C or less, and even more preferably 220°C or less. There is no particular restriction on the lower limit of the melting point of the aromatic carboxylic acid, but it may be, for example, 80°C or more, 100°C or more, or 120°C or more.

[0016] Examples of aromatic carboxylic acids include compounds having a benzene ring, aromatic polycyclic compounds having multiple benzene rings bonded thereto, such as biphenyl and benzophenone, condensed ring compounds such as naphthalene rings, anthracene, and phenanthrene, and heteroaromatic compounds having a ring structure composed of multiple elements such as carbon, nitrogen, and oxygen, such as pyridine, furan, and indole. From the viewpoint of solubility in epoxy resins, compounds having three or fewer rings per molecule are preferred. Examples of preferred aromatic carboxylic acids include salicylic acid, methylenedisalicylic acid, 2-hydroxy-1-naphthoic acid, 3-methylsalicylic acid, 2,5-dihydroxybenzoic acid, 3-phenylsalicylic acid, and benzoic acid. Aromatic carboxylic acids may be used singly or in combination.

[0017] The aliphatic carboxylic acid is a linear or branched saturated aliphatic carboxylic acid containing one carboxy group and one hydroxy group. From the viewpoint of solubility in epoxy resins, the number of carbon atoms in the aliphatic carboxylic acid is preferably 2 or 3. In this specification, the number of carbon atoms in the aliphatic carboxylic acid refers to the number of carbon atoms remaining in the entire compound, excluding the carbon atoms constituting the carboxy group.

[0018] A preferred example of the aliphatic carboxylic acid is lactic acid.

[0019] When the curing agent composition is taken as 100% by mass, the aromatic carboxylic acid or aliphatic carboxylic acid is preferably contained in the curing agent composition in an amount of 1 to 20% by mass, more preferably 1.5 to 15% by mass, and even more preferably 2 to 10% by mass. When the amount of the aromatic carboxylic acid or aliphatic carboxylic acid is within the above range, curing of the epoxy resin by the dihydrazide compound can be sufficiently promoted.

[0020] From the viewpoint of accelerating the curing of the epoxy resin composition, the aromatic carboxylic acid or aliphatic carboxylic acid in the present invention preferably does not contain any functional group other than a carboxy group or a hydroxy group, such as an amino group, a formyl group, a carbonyl group, a thiol group, a sulfonic acid group, or a halogen atom.

[0021] The curing agent composition may optionally contain moisture, unreacted materials from the synthesis of the dihydrazide compound, and the like, within the range that does not impair the effects of the present invention.

[0022] There are no particular limitations on the method for producing the curing agent composition, and the curing agent composition can be obtained by mixing a dihydrazide compound, an aromatic carboxylic acid or an aliphatic carboxylic acid, and optionally other components.

[0023] The present invention also relates to an epoxy resin composition containing the curing agent composition and (C) an epoxy resin.

[0024] As the epoxy resin contained in the epoxy resin composition, any conventionally known epoxy resin can be used without any particular limitation. The epoxy resin can be appropriately selected depending on the application and the desired properties of the cured product, and one type may be used alone or two or more types may be used in combination. The epoxy resin may be liquid or solid. A mixture of a liquid resin and a solid resin may also be used. Here, "liquid" and "solid" refer to the state of the epoxy resin at room temperature (25°C).

[0025] Preferred liquid epoxy resins are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, and epoxy resins having a butadiene structure. Specific examples of liquid epoxy resins include DIC's "HP4032," "HP4032D," and "HP4032SS" (naphthalene-type epoxy resins); Mitsubishi Chemical's "828US," "jER828EL" (bisphenol A-type epoxy resin), "jER807" (bisphenol F-type epoxy resin), "jER152" (phenol novolac-type epoxy resin), and "YL7760" (bisphenol AF-type epoxy resin); Nippon Steel & Sumitomo Metal Chemical's "ZX1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin); Nagase ChemteX's "EX-721" (glycidyl ester-type epoxy resin); and Daicel's "Celloxide 2021P" (alicyclic epoxy resin with an ester skeleton) and "PB-3600" (epoxy resin with a butadiene structure).

[0026] Preferred solid epoxy resins include naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, and tetraphenylethane-type epoxy resins. Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), "N-690" (cresol novolac-type epoxy resin), "N-695" (cresol novolac-type epoxy resin), "HP-7200" (dicyclopentadiene-type epoxy resin), "HP-7200HH", "EXA7311", "EXA7311-G3", "EXA7311-G4", "EXA7311-G4S", and "HP6000" (naphthylene ether-type epoxy resin), manufactured by DIC Corporation, and "EPPN-502H" (trisphenol-type epoxy resin), "NC7000L" (naphthol novolac-type epoxy resin), and "NC3000H" manufactured by Nippon Kayaku Co., Ltd. "," "NC3000," "NC3000L," and "NC3100" (biphenyl-type epoxy resins), Nippon Steel & Sumitomo Metal Chemical Co., Ltd.'s "ESN475V" (naphthol-type epoxy resin) and "ESN485" (naphthol novolac-type epoxy resin), Mitsubishi Chemical Corporation's "YX4000H," "YL6121" (biphenyl-type epoxy resin), "YX4000HK" (bixylenol-type epoxy resin), and "YX8800" (anthracene-type epoxy resin), Osaka Gas Chemicals Co., Ltd.'s "PG-100" and "CG-500," Mitsubishi Chemical Corporation's "YL7800" (fluorene-type epoxy resin), Mitsubishi Chemical Corporation's "jER1010" (solid bisphenol A-type epoxy resin), and "jER1031S" (tetraphenylethane-type epoxy resin), and the like.

[0027] From the viewpoints of ease of uniform mixing with the curing agent composition and adhesiveness, it is preferable that at least 10% by mass or more of the total epoxy resin used be liquid, more preferably at least 30% by mass or more, even more preferably at least 50% by mass or more, and particularly preferably at least 80% by mass or more.

[0028] The epoxy equivalent of the epoxy resin is, for example, 50 to 1000 g / eq, preferably 100 to 500 g / eq, and more preferably 150 to 300 g / eq. Here, the epoxy equivalent is the mass of the epoxy resin per equivalent of epoxy groups, and can be measured in accordance with JIS K7236 (2009).

[0029] The content of the epoxy resin in the epoxy resin composition is not particularly limited, but is preferably 50 to 95 mass %, more preferably 60 to 90 mass %, and even more preferably 65 to 85 mass %.

[0030] The epoxy resin and curing agent composition are blended in such an amount that the total equivalent of the (A) dihydrazide compound and (B) aromatic carboxylic acid or aliphatic carboxylic acid is preferably 0.8 to 1.2, more preferably 0.9 to 1.1, relative to the epoxy equivalent of the (C) epoxy resin of 1. If the blending amount is within the above range, it is possible to suppress the residue of unreacted epoxy resin.

[0031] The epoxy resin composition may further contain one or more selected from the group consisting of a curing agent other than component (A), a curing accelerator other than component (B), a thermosetting resin, a thermoplastic resin, an inorganic filler, an organic filler, a thickener, an antifoaming agent, a leveling agent, an adhesion promoter, a colorant, an organic solvent, and water.

[0032] The curing agent refers to an epoxy resin curing agent other than the component (A) of the present invention, and is preferably a latent curing agent, and examples thereof include urea compounds, amine compounds, thiol compounds, acid anhydride compounds, guanidine compounds, hydrazide compounds, phenol compounds, naphthol compounds, active ester compounds, benzoxazine compounds, cyanate ester compounds, and carbodiimide compounds.

[0033] The urea compound is not particularly limited as long as it has a urea group and can react with an epoxy resin, but aromatic dimethylurea or aliphatic dimethylurea is preferred. Preferred aromatic dimethylureas include N,N-dimethyl-N'-phenylurea, N,N-dimethyl-N'-(3,4-dichlorophenyl)urea, 4,4'-methylenebis(phenyldimethylurea), and toluenebisdimethylurea. Preferred aliphatic dimethylureas include dimethylaminocarboxylaminomethyltrimethylcyclohexyldimethylurea.

[0034] The amine compound is preferably at least one selected from the group consisting of imidazole compounds, salts of imidazole and acidic compounds, amine compounds, salts of amine compounds and acidic compounds, and amine adduct compounds.

[0035] The preparation of the epoxy resin composition is not particularly difficult and can be carried out in accordance with a conventionally known method. For example, the epoxy resin composition can be prepared by mixing the components of the curing agent composition, the epoxy resin, and optionally other components. Any conventionally known mixing means can be used without any particular limitation as the mixing means. For example, stirring may be carried out using a commercially available planetary stirrer.

[0036] The use of the curing agent composition of the present invention allows for the production of epoxy resin compositions with excellent curing properties. The curing properties of epoxy resin compositions can be evaluated, for example, using a hotplate gelation tester (GT-D, manufactured by Nissin Chemical Co., Ltd.) by placing approximately 0.5 g of the resin composition on a hotplate heated to a specific temperature (e.g., between 100 and 150°C) so that the resin composition is within a diameter of 25 mm, stirring with a spatula with a tip width of approximately 5 mm at one rotation per second, lifting the spatula to a height of 30 mm above the top surface of the hotplate, and measuring the time until the composition no longer forms a string (gel time). The shorter the gel time, the higher the curing properties. The shorter the gel time, especially at 100°C, the better the low-temperature curing properties.

[0037] The epoxy resin composition can be used as an epoxy resin material in various fields, such as architecture, civil engineering, automobiles, ships, aerospace, industrial machinery, robots, communications, electrical and electronics, semiconductors, displays, etc. More specifically, it can be used as an adhesive, bonding agent, conductive material, magnetic material, heat conductive material, insulating material, sealing material, coating material, vibration damping / anti-vibration material, soundproofing material, filler, paint, etc.

[0038] The present invention also relates to an adhesive containing an epoxy resin composition. The adhesive is preferably suitable for use in the field of adhesives for electronic components. In addition to the epoxy resin composition of the present invention, the adhesive may optionally contain various additives, such as epoxy resin curing agents other than Components A and B, curing accelerators, flame retardants, storage stability improvers, fillers, diluents, solvents, pigments, flexibility-imparting agents, coupling agents, antioxidants, anti-settling agents, and dispersants.

[0039] The present invention also relates to an encapsulant containing the epoxy resin composition. The encapsulant is an encapsulating material such as an underfill agent for flip-chip mounting or a chip-on-board encapsulant. In addition to the epoxy resin composition of the present invention, the encapsulant may optionally contain various additives such as epoxy resin curing agents other than Components A and B, curing accelerators, flame retardants, storage stability improvers, fillers, diluents, solvents, pigments, flexibility-imparting agents, coupling agents, antioxidants, anti-settling agents, and dispersants.

[0040] The present invention also relates to a cured product obtained by curing the above-mentioned epoxy resin composition and an electronic device containing the cured product. Examples of electronic devices include LEDs, semiconductors, lasers, solar cells, and organic EL devices.

[0041] Curing of the epoxy resin composition is not particularly difficult and can be carried out in accordance with a conventionally known method. For example, the obtained epoxy resin composition can be cured by heating. Heating is suitably carried out at a temperature of, for example, 60 to 150°C, preferably 70 to 130°C, and more preferably 80 to 120°C for, for example, 1 to 120 minutes, preferably 3 to 100 minutes, and more preferably 5 to 80 minutes.

[0042] The cured product of the epoxy resin composition of the present invention has high transparency. The transparency of the cured product can be evaluated, for example, by measuring the light transmittance spectrum of a cured product obtained under specific curing conditions using a fiber spectrophotometer (MCPD-7700, Model 311C, manufactured by Otsuka Electronics Co., Ltd., external light source unit: halogen lamp MC-2564 (24V, 150W specification)) equipped with an 80mm φ integrating sphere (model SRS-99-010, reflectance 99%), and then calculating the total light transmittance at 400 nm of the cured product from the obtained light transmittance spectrum. The higher the total light transmittance, the better the transparency. [Example]

[0043] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0044] [Preparation of Epoxy Resin Composition] To 100 parts by mass of an epoxy resin (jER828EL, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 190), a dihydrazide compound and the aromatic carboxylic acid of the present invention (Examples 1-7, 9-12), the aliphatic carboxylic acid of the present invention (Example 8), or a comparative substance (Comparative Examples 2-9) were added so as to obtain the composition shown in Tables 1-3, and the mixture was stirred for 2 minutes using a revolving centrifugal mixer (Thinky Corporation, ARE-250 "Awatori Rentaro") to obtain a resin composition. In Comparative Examples 1 and 10-13, only the dihydrazide compound was added to the epoxy resin and stirred. The dihydrazide compounds used were as follows:

[0045] VDH-J: 1,3-bis(hydrazinocarbonoethyl)-5-isopropylhydantoin (Ajinomoto Fine-Techno Co., Ltd., median diameter 2 μm) UDH-J: 7,11-octadecadiene-1,18-dicarbohydrazide (Ajinomoto Fine-Techno Co., Ltd., median diameter 2 μm) ADH: Adipic acid dihydrazide (Nihon Finechem Co., Ltd., median diameter 13 μm) N-12: Dodecanedioic acid dihydrazide (manufactured by Nippon Finechem Co., Ltd., median diameter 9 μm) IDH: Isophthalic dihydrazide (Nippon Finechem Co., Ltd.)

[0046] [Gel time measurement] Using a hot plate gelation tester (GT-D, manufactured by Nissin Chemical Co., Ltd.), approximately 0.5 g of the resin composition was placed on a hot plate heated to 100°C for compositions containing VDH-J as a dihydrazide compound, or to 130°C, 140°C, or 150°C for compositions containing compounds other than VDH-J. The composition was placed on a hot plate with a diameter of 25 mm and stirred with a spatula with a tip width of approximately 5 mm at one rotation per second. The composition was then lifted to a height of 30 mm from the top of the hot plate, and the time until the composition no longer formed strings was recorded as the gel time. The results are shown in Tables 1 to 3.

[0047] [Measurement of transparency of cured product] 2 ml of each epoxy resin composition was poured into a 3 cm diameter, smooth-bottomed canister, taking care to avoid air bubbles. The resin formulation was spread using a spatula to fill the entire bottom of the canister. The composition was then heated in a hot-air circulating oven for 30 minutes at 100 °C for compositions containing VDH-J as a dihydrazide compound, and at 130 °C, 140 °C, or 150 °C for compositions other than VDH-J. The cured product was then peeled from the canister without scratching. The light transmittance spectra of the cured products were measured using a fiber-optic spectrophotometer (MCPD-7700, Model 311C, Otsuka Electronics Co., Ltd., external light source unit: halogen lamp MC-2564 (24 V, 150 W specification)) equipped with an 80 mm φ integrating sphere (Model SRS-99-010, reflectance 99%). The total light transmittance at 400 nm of the cured product was calculated from the obtained light transmittance spectra. The results are shown in Tables 1 to 3.

[0048] [Table 1] [Table 2] [Table 3]

[0049] Comparing Examples 1 to 8, which contain VDH-J as a dihydrazide compound, with Comparative Examples 1 to 9, Examples 1 to 8, which contain a carboxylic acid compound of the present invention, had a shorter gel time than Comparative Example 1, which does not contain a carboxylic acid compound of the present invention or a comparative substance, and Comparative Examples 2 to 9, which contain similar amounts of a comparative substance. Furthermore, when Examples 9 to 12, which contain a dihydrazide compound other than VDH-J, and Comparative Examples 10 to 13, which contain the same dihydrazide compound, were compared, Examples 9 to 12, which contain a carboxylic acid compound of the present invention, had a shorter gel time than Comparative Examples 10 to 13, which do not contain a carboxylic acid compound of the present invention or a comparative substance.

[0050] In measuring the transparency of the cured products, the curability was insufficient in all of Comparative Examples 1 to 13, and therefore no cured products suitable for measurement were obtained, whereas cured products were obtained in all of Examples 1 to 12. When the transmittance was measured for Examples 1 to 12, in which cured products were obtained, it was found that the lower the melting point of the dihydrazide compound used, the higher the transparency tended to be, and cured products with particularly high transparency were obtained from compositions containing VDH-J. [Industrial Applicability]

[0051] An epoxy resin composition using the curing agent composition of the present invention can be suitably used as an adhesive or a sealant, and the cured product thereof can be used as an electronic device.

Claims

1. (A) a dihydrazide compound; (B) an aliphatic carboxylic acid; a curing agent composition comprising: (C) an epoxy resin, An epoxy resin composition comprising: the aliphatic carboxylic acid is a linear or branched saturated aliphatic carboxylic acid containing one carboxy group and one hydroxy group; the content of the epoxy resin in the epoxy resin composition is 50 to 95% by mass, At least 10% by mass of the epoxy resin is liquid at 25°C. Epoxy resin composition.

2. An epoxy resin composition as described in claim 1, wherein the aliphatic carboxylic acid has 2 or 3 carbon atoms.

3. 3. The epoxy resin composition according to claim 2, wherein the aliphatic carboxylic acid is lactic acid.

4. 2. The epoxy resin composition according to claim 1, wherein the dihydrazide compound has a melting point of 250°C or less.

5. 5. An epoxy resin material comprising the epoxy resin composition according to claim 1, wherein the epoxy resin material is selected from the group consisting of adhesives, bonding agents, conductive materials, magnetic materials, thermally conductive materials, insulating materials, sealing materials, coating materials, vibration damping / anti-vibration materials, soundproofing materials, fillers, and paints.

6. The epoxy resin material according to claim 5, which is an adhesive or a sealant.

7. A cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 4.

8. An electronic device comprising the cured product according to claim 7.

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