JP2017149900A - Epoxy resin composition, and cured product thereof, and adhesive prepared therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition comprising a compound obtained from biomass resources and showing excellent adhesiveness and low-temperature quick curability.SOLUTION: The present invention provides an epoxy resin composition comprising (a) epoxy resin and (b) polycarboxylic acid having a cyclic ester structure.SELECTED DRAWING: None

Description

  The present invention relates to an epoxy resin composition having a wide range of uses for adhesives, paints, electrical and electronic materials, and the use thereof.

  In recent years, biomass resources have attracted attention as carbon neutral resources from the viewpoint of environmental problems. It is known that polycarboxylic acids having a cyclic ester structure such as 2-pyrone-4,6-dicarboxylic acid (hereinafter abbreviated as “PDC”) can be obtained by microbial conversion from lignin, which is the main biomass resource ( Patent Document 1).

On the other hand, epoxy resin compositions are used in the fields of electrical and electronic parts, structural materials, adhesives, paints, etc. due to their workability and excellent electrical properties, heat resistance, adhesion, moisture resistance (water resistance), etc. Widely used. In such fields, epoxy resin compositions using biomass-derived compounds have been studied. Patent Document 2 reports an epoxidized product of lignin and a cured product thereof.
Patent Document 3 reports an epoxy resin composition containing a diglycidyl ester derived from a polycarboxylic acid having a cyclic ester structure.

JP 2005-278549 A JP 2006-066237 A JP 2010-59095 A

However, since patent document 2 uses the lignin extracted from the plant as it is, it is a very high molecular weight compound, and the moldability of the epoxy resin composition using the compound may be difficult. In addition, since it contains ionic impurities and has a high water absorption rate, there is a problem that it is difficult to provide a high level of reliability that can withstand the use of electrical and electronic materials. Further, Patent Document 3 requires the use of an expensive condensing agent for the production of an epoxy resin, and the production cost becomes very high due to the low yield of PDC. Is required.
The objective of this invention is providing the epoxy resin composition which contains the compound obtained from biomass resources and shows the outstanding adhesiveness and low-temperature fast-curing property.

  In order to solve the above-mentioned problems, the present inventors have paid attention to the use of a polycarboxylic acid having a cyclic ester structure as a curing agent for epoxy resins. As a result of various studies, the present invention has been completed.

That is, the present invention is as follows.
[1] An epoxy resin composition containing (a) an epoxy resin and (b) a polycarboxylic acid having a cyclic ester structure.
[2] The epoxy resin composition according to [1], wherein the cyclic ester structure is a saturated or unsaturated cyclic ester structure having 3 to 6 carbon atoms.
[3] The above-mentioned [1], wherein (b) the polycarboxylic acid having a cyclic ester structure has two or more carboxyl groups bonded to the cyclic ester structure directly or via an alkyl chain having 1 to 6 carbon atoms. The epoxy resin composition according to [2].
[4] The epoxy resin composition according to any one of [1] to [3], wherein the polycarboxylic acid (b) having a cyclic ester structure is 2-pyrone-4,6-dicarboxylic acid.
[5] The epoxy resin composition according to any one of [1] to [3], wherein the polycarboxylic acid (b) having a cyclic ester structure is 3-carboxymuconolactone.
[6] A cured product obtained by curing the epoxy resin composition according to any one of [1] to [5].
[7] An adhesive using the epoxy resin composition according to any one of [1] to [5].

  The epoxy resin composition of the present invention has a low-temperature fast-curing property, and the cured product has excellent adhesiveness. Therefore, it can be widely used in the fields of electric / electronic parts, structural materials, adhesiveness, paints, and the like. it can.

The present invention is described in detail below.
The epoxy resin composition of the present invention contains at least (a) an epoxy resin and (b) a polycarboxylic acid having a cyclic ester structure.
The (a) epoxy resin used in the present invention is not particularly limited, but preferably contains a bifunctional or higher functional epoxy resin. Examples of the bifunctional or higher epoxy resin include polyfunctional epoxy resins that are glycidyl etherified products of polyphenol compounds, polyfunctional epoxy resins that are glycidyl etherified products of various novolak resins, alicyclic epoxy resins, heterocyclic epoxy resins, and glycidyl. Examples thereof include, but are not limited to, ester epoxy resins, glycidyl amine epoxy resins, epoxy resins obtained by glycidylation of halogenated phenols, and the like.

  Examples of polyfunctional epoxy resins that are glycidyl etherification products of polyphenol compounds include bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, tetramethylbisphenol A, dimethylbisphenol A, tetramethylbisphenol F, and dimethylbisphenol F. , Tetramethylbisphenol S, dimethylbisphenol S, tetramethyl-4,4′-biphenol, dimethyl-4,4′-biphenylphenol, 1- (4-hydroxyphenyl) -2- [4- (1,1-bis -(4-hydroxyphenyl) ethyl) phenyl] propane, 2,2'-methylene-bis (4-methyl-6-tert-butylphenol), 4,4'-butylidene-bis (3-methyl-6-tert- Butyl Fe ), Trishydroxyphenylmethane, resorcinol, hydroquinone, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, and polyphenols such as phenolized polybutadiene The polyfunctional epoxy resin which is the glycidyl etherified compound of a compound is mentioned.

  Examples of polyfunctional epoxy resins that are glycidyl etherified products of various novolak resins include, for example, various phenols such as phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol F, bisphenol S, naphthols, and the like. Glycidyl etherified products of various novolac resins such as novolak resins, xylylene skeleton-containing phenol novolak resins, dicyclopentadiene skeleton-containing phenol novolak resins, biphenyl skeleton-containing phenol novolak resins, fluorene skeleton-containing phenol novolak resins, and furan skeleton-containing phenol novolak resins. Can be mentioned.

  Examples of the alicyclic epoxy resin include alicyclic epoxy resins having an aliphatic skeleton such as cyclohexane, such as Celoxide 2021P, Epolide GT301, Epolide GT401 (manufactured by Daicel Chemical Industries). Examples of the aliphatic epoxy resin include glycidyl ethers of polyhydric alcohols such as 1,4-butanediol, 1,6-hexanediol, polyethylene glycol, and pentaerythritol.

  Examples of the heterocyclic epoxy resin include heterocyclic epoxy resins having a heterocyclic ring such as an isocyanuric ring and a hydantoin ring. Examples of the glycidyl ester-based epoxy resin include epoxy resins made of carboxylic acids such as hexahydrophthalic acid diglycidyl ester. Examples of the glycidylamine-based epoxy resin include epoxy resins obtained by glycidylating amines such as aniline and toluidine.

  Examples of epoxy resins obtained by glycidylation of halogenated phenols include brominated bisphenol A, brominated bisphenol F, brominated bisphenol S, brominated phenol novolac, brominated cresol novolac, chlorinated bisphenol S, and chlorinated bisphenol A. An epoxy resin obtained by glycidylation of halogenated phenols can be mentioned.

  Of the above-mentioned epoxy resins, which epoxy resin is used is appropriately selected depending on required properties, but glycidyl ether type epoxy resins are preferable, and bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenols are more preferable. S type epoxy resin, 2,2'-diallyl bisphenol A type epoxy resin, hydrogenated bisphenol type epoxy resin, propylene oxide added bisphenol A type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclo Pentadiene type epoxy resin, naphthalene type epoxy resin, novolak type epoxy resin having phenol skeleton and naphthol skeleton, novolak type epoxy resin having phenol skeleton and biphenyl skeleton, Novolak type epoxy resin having a re phenyl methane skeleton, a novolac type epoxy resin having a dicyclopentadiene skeleton. The novolak type epoxy resin having a phenol skeleton and a naphthol skeleton is more preferably one having a methyl group in the phenol skeleton, such as NC-7000 (trade name: manufactured by Nippon Kayaku Co., Ltd.), NC-7300 (trade name: Nippon Kayaku Co., Ltd.). A novolac type epoxy resin having a phenol skeleton and a biphenyl skeleton is commercially available, for example, as NC-3000 (trade name: manufactured by Nippon Kayaku Co., Ltd.). Novolak type epoxy resins having a triphenylmethane skeleton are commercially available, for example, as EPPN-501H and EPPN-502H (trade names: manufactured by Nippon Kayaku Co., Ltd.). A novolac-type epoxy resin having a dicyclopentadiene skeleton is commercially available, for example, as XD-1000 (trade name: manufactured by Nippon Kayaku Co., Ltd.). Furthermore, these epoxy resins can be used as one kind or a mixture of two or more kinds as required, such as heat resistance and flame retardancy.

  The polycarboxylic acid (b) having a cyclic ester structure used in the present invention is not particularly limited as long as it has a cyclic ester structure in the molecular skeleton and has two or more carboxyl groups. A polycarboxylic acid having a structure of a saturated or unsaturated cyclic ester structure having 3 to 6 carbon atoms, in which two or more carboxyl groups are bonded to the cyclic ester structure directly or via an alkyl chain having 1 to 6 carbon atoms is preferable. . Since it can be produced from biomass resources, 2-pyrone-4,6-dicarboxylic acid, 3,4,5,6-tetrahydro-2-pyrone-4,6-dicarboxylic acid, 3-carboxymuconolactone, 2 , 3-dihydro-3-carboxymuconolactone is more preferable. 2-pyrone-4,6-dicarboxylic acid and 3-carboxymuconolactone are particularly preferable because they can be obtained directly by microbial conversion.

  2-pyrone-4,6-dicarboxylic acid is a low plant-derived material such as lignin such as vanillin, syringaldehyde, vanillic acid, syringic acid or protocatechuic acid, for example, by the method described in JP-A-2005-278549. It can be easily obtained from a molecular compound or a mixture thereof. 3-Carboxymuconolactone can be similarly easily obtained by the method described in WO2008 / 018640.

  (B) The usage-amount of polycarboxylic acid which has cyclic ester structure is the range of 0.3-2.0 normally in the equivalent ratio of the carboxyl group with respect to the epoxy group of (a) epoxy resin, Preferably it is 0.4- It is in the range of 1.6, more preferably in the range of 0.5 to 1.3.

  In the epoxy resin composition of the present invention, a curing accelerator may be used in combination with (a) an epoxy resin and (b) a polycarboxylic acid having a cyclic ester structure. Specific examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-ethylimidazole and 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo ( Quaternary amines such as 5,4,0) undecene-7, phosphines such as triphenylphosphine, tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, etc. Quaternary phosphonium salts such as ammonium salt, triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, tetrabutylphosphonium salt (counter ion of quaternary salt is not particularly specified, such as halogen, organic acid ion, hydroxide ion, etc.) , Especially organic acid ions, water Iodide ion.), Metal compounds such as tin octylate, and microcapsule type curing accelerator or the like of these curing accelerators to the microcapsules and the like. As for the usage-amount in the case of using a hardening accelerator, 0.01-5.0 mass parts is preferable with respect to 100 mass parts of epoxy resins.

  The epoxy resin composition of the present invention may further contain a phosphorus-containing compound as a flame retardant component. The phosphorus-containing compound that can be used may be a reactive type or an additive type. Specific examples of phosphorus-containing compounds include trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylylenyl phosphate, 1,3-phenylenebis ( Phosphoric acid esters such as dixylylenyl phosphate), 1,4-phenylenebis (dixylylenyl phosphate), 4,4′-biphenyl (dixylylenyl phosphate); 9,10-dihydro-9-oxa Phosphanes such as -10-phosphaphenanthrene-10-oxide, 10 (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide; epoxy resin and active hydrogen of the phosphanes A phosphorus-containing product obtained by reacting with Poxy compounds, red phosphorus and the like can be mentioned, and phosphoric esters, phosphanes or phosphorus-containing epoxy compounds are preferable, and 1,3-phenylenebis (dixylylenyl phosphate), 1,4-phenylenebis (dixylylene). Nyl phosphate), 4,4′-biphenyl (dixylylenyl phosphate) or phosphorus-containing epoxy compounds are particularly preferred. The content of the phosphorus-containing compound is preferably phosphorus-containing compound / total epoxy resin = 0.1 to 0.6 (mass ratio). If it is 0.1 or less, flame retardancy may be insufficient, and if it is 0.6 or more, it may adversely affect the hygroscopicity and dielectric properties of the cured product.

Furthermore, you may add antioxidant to the epoxy resin composition of this invention as needed. Examples of the antioxidant that can be used include phenolic antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.
Specific examples of phenolic antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β- (3 , 5-di-t-butyl-4-hydroxyphenyl) propionate, isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,4-bis- (n-octylthio)- Monophenols such as 6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 2,4-bis [(octylthio) methyl] -o-cresol; 2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl) -6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) Propionate], 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t- Butyl-4-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,5-di-t- Butyl-4-hydroxybenzyl phosphonate-diethyl ester, 3,9-bis [1,1-dimethyl-2- {β- (3-t-butyl-4-hydroxy-5-methyl Enyl) propionyloxy} ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane, bisphenols such as bis (3,5-di-t-butyl-4-hydroxybenzylsulfonate) calcium 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t- Butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis- (4 '-Hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 1 , 3,5-tris (3 ′, 5′-di-t-butyl-4′-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione, tocophenol, etc. Molecular type phenols are exemplified.

  Specific examples of the sulfur antioxidant include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, and the like. The

  Specific examples of phosphorus antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris (2,4-di-t- Butylphenyl) phosphite, cyclic neopentanetetrayl bis (octadecyl) phosphite, cyclic neopentanetetraylbi (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbi (2,4 -Di-t-butyl-4-methylphenyl) phosphite, bis [2-t-butyl-6-methyl-4- {2- (octadecyloxycarbonyl) ethyl} phenyl] hydrogen phosphite, etc. 9,10-dihydro 9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 -Oxaphosphaphenanthrene oxides such as 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are exemplified.

  These antioxidants can be used alone, but two or more of them may be used in combination. In the present invention, a phosphorus-based antioxidant is particularly preferable. The usage-amount of antioxidant is 0.008-1 mass part normally with respect to 100 mass parts of resin components in the epoxy resin composition of this invention, Preferably it is 0.01-0.5 mass part.

  Furthermore, you may add a light stabilizer to the epoxy resin composition of this invention as needed. As the light stabilizer, hindered amine-based light stabilizers, particularly HALS and the like are suitable. HALS is not particularly limited, but representative examples include dibutylamine, 1,3,5-triazine, N, N′-bis (2,2,6,6-tetramethyl-4- Polycondensate of piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy succinate -2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], bis (1,2,2, 6,6-pentamethyl-4- Peridyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di -T-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), etc. Only one HALS is used. Two or more types may be used in combination.

  Furthermore, a binder resin can also be mix | blended with the epoxy resin composition of this invention as needed. Examples of the binder resin include butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenol resins, epoxy-NBR resins, polyamide resins, polyimide resins, and silicone resins. However, it is not limited to these. The blending amount of the binder resin is preferably in a range that does not impair the flame retardancy and heat resistance of the cured product, and is usually 0.05 to 50 parts by mass, preferably 0.05 to 20 parts per 100 parts by mass of the resin component. A mass part is used as needed.

  If necessary, an inorganic filler can be added to the epoxy resin composition of the present invention. Examples of inorganic fillers include crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, fosterite, steatite, spinel, titania, talc, and the like. Preferred examples include, but are not limited to, beads made of spheroids. These may be used alone or in combination of two or more. In the epoxy resin composition of the present invention, the content of these inorganic fillers is used in an amount that occupies 0 to 95% by mass in the entire composition. Furthermore, the epoxy resin composition of the present invention contains various combinations of a silane coupling agent, a release agent such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, a surfactant, a dye, a pigment, and an ultraviolet absorber. An agent and various thermosetting resins can be added.

  The epoxy resin composition of this invention is obtained by mixing each component uniformly. For example, in the present invention, (a) an epoxy resin, (b) a polycarboxylic acid having a cyclic ester structure, and, if necessary, a curing agent, a curing accelerator, a phosphorus-containing compound, a binder resin, an inorganic filler, a compounding agent, and the like are blended and extruded. The epoxy resin composition of the present invention can be obtained by sufficiently mixing until uniform using a machine, kneader, roll or the like.

  The epoxy resin composition of the present invention is formed by potting, melting (without melting in the case of liquid) using a casting or transfer molding machine, and further heating at 60 to 200 ° C. for 1 to 10 hours. The cured product of the invention can be obtained.

  The epoxy resin composition of the present invention can be obtained as a varnish composition by uniformly mixing (a) an epoxy resin, (b) a polycarboxylic acid having a cyclic ester structure, and other additives in a solvent. Examples of the solvent include organic solvents such as methyl ethyl ketone, toluene, xylene, ethyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, cyclohexanone, cyclopentanone, and propylene glycol diacetate. The compounding quantity of the solvent in this case is 10-70 mass% normally in the mixture of the epoxy resin composition of this invention and this solvent, Preferably the quantity which occupies 15-70 mass% is used.

  After the epoxy resin composition of the present invention is made into a varnish composition, a prepreg obtained by impregnating a base material such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc. and drying by heating is heated. It can be set as the hardened | cured material of an epoxy resin composition by press-molding. Moreover, if it is a liquid composition, the hardened | cured material of the epoxy resin composition containing a carbon fiber can also be obtained as it is, for example by the RTM system.

  Curing of the epoxy resin composition of the present invention is mainly carried out by heat curing. For example, it is used in combination with a catalyst around room temperature, room temperature curing caused by oxygen or moisture, photocuring caused by an acid generated by ultraviolet irradiation, or the like. It is also possible.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. The following materials, processing details, processing procedures, and the like can be changed as appropriate without departing from the spirit of the present invention. In Examples and Comparative Examples, “part” means “part by mass”.

[Examples 1-3, Comparative Examples 1-2]
According to the blending ratio described in Table 1, each material was mixed using a planetary stirrer (“Shinky Co., Ltd.“ Awatori Netaro ”), and then mixed using three rolls to form an epoxy resin composition. A product was prepared. About the characteristic of the obtained epoxy resin composition, the gel time in 120 degreeC and 150 degreeC was measured and evaluated with the following measuring methods. The results are shown in Table 1.
[Measurement of gel time]
Conforms to JIS-5600-1 Unit is second.

Epoxy resin A: bisphenol A type epoxy resin RE-310; Nippon Kayaku Co., Ltd. epoxy resin B: Bisphenol F type epoxy resin RE-303SL; Nippon Kayaku Co., Ltd. epoxy resin C: alkyl glycidyl ether 200; New Nippon Rika Co., Ltd. polycarboxylic acid A: 2-pyrone-4,6-dicarboxylic acid polycarboxylic acid B: isophthalic anhydride: 4-methylhexahydrophthalic anhydride Ricacid MH; Co., Ltd. curing accelerator: Triphenylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.)

  From Table 1, comparing the gel time measurement results, the epoxy resin composition of the present invention has a shorter curing time than a comparative epoxy resin composition using a polycarboxylic acid or acid anhydride having a similar skeleton, It was confirmed that the reaction rate during the curing reaction was fast.

Examples 4-6, Comparative Examples 3-6
In order to make the thickness of the adhesive layer uniform in the obtained epoxy resin composition, 1% of glass fiber having a diameter of 5 μm was added as a spacer and sufficiently mixed and stirred. The epoxy resin composition containing this glass fiber was apply | coated to the glass substrate, the glass piece of 1.5 mm x 1.5 mm was bonded together, and it heated in oven of the predetermined curing temperature for 1 hour, and obtained hardened | cured material.
About the obtained hardened | cured material, the shear adhesive strength in predetermined | prescribed hardening temperature was measured and evaluated with the following measuring methods. The results are shown in Table 2.
(Measurement of shear bond strength)
The shear bond strength between the glass substrate and the glass piece was measured using a bond tester (SS-30WD, manufactured by Seishin Shoji Co., Ltd.). The unit is MPa.

  From Table 2, from the measurement result of the shear bond strength, the epoxy resin composition of the present invention is cured at 80 ° C. as compared with a comparative epoxy resin composition using a polycarboxylic acid or acid anhydride having a similar skeleton. It was confirmed that the adhesiveness was sufficiently strong even at temperature.

  Since the epoxy resin composition of the present invention uses a compound obtained from biomass resources, it not only contributes to a carbon recycling society, but also has excellent curing characteristics such as low-temperature curability, fast curability, and adhesive strength. For example, adhesives, bonding pastes, conductive materials, anisotropic conductive materials, insulating materials, sealing materials, coating materials, coating compositions, prepregs, heat conductive materials, fuel cell separators It is useful in applications such as materials and overcoat agents for flexible wiring boards.

Claims (7)

  An epoxy resin composition comprising (a) an epoxy resin and (b) a polycarboxylic acid having a cyclic ester structure.   The epoxy resin composition according to claim 1, wherein the cyclic ester structure is a saturated or unsaturated cyclic ester structure having 3 to 6 carbon atoms.   In the polycarboxylic acid (b) having a cyclic ester structure, two or more carboxyl groups are bonded to the cyclic ester structure directly or via an alkyl chain having 1 to 6 carbon atoms. The epoxy resin composition as described.   The epoxy resin composition according to any one of claims 1 to 3, wherein the polycarboxylic acid (b) having a cyclic ester structure is 2-pyrone-4,6-dicarboxylic acid.   The epoxy resin composition according to any one of claims 1 to 3, wherein the polycarboxylic acid (b) having a cyclic ester structure is 3-carboxymuconolactone.   Hardened | cured material which hardened | cured the epoxy resin composition of any one of Claims 1-5.   The adhesive agent using the epoxy resin composition of any one of Claims 1-5.