Epoxy resin composition, sealing material, conductive material, thermally conductive material, insulating material, adhesive for camera module, structural adhesive, matrix resin for fiber-reinforced plastic, impregnation fixing agent, interlayer insulating film, film-type solder resist, sealing sheet, conductive film, anisotropic conductive film, and thermally conductive film

Abstract

An epoxy resin composition according to the invention includes an epoxy resin (A) and a curing agent (B), wherein, in an infrared absorption spectrum of the epoxy resin composition measured by infrared spectroscopy, the ratio (P2 / P1) of the maximum peak intensity (P1) in the range of 880-950 cm-1 to the maximum peak intensity (P2) in the range of 2200-2350 cm-1 is 0.005-0.2.

Description

Epoxy resin compositions, encapsulants, conductive materials, thermally conductive materials, insulating materials, adhesives for camera modules, structural adhesives, matrix resins for fiber-reinforced plastics, impregnation adhesives, interlayer insulating films, film-type solder resists, encapsulating sheets, conductive films, anisotropic conductive films, and thermally conductive films.

[0001] The present invention relates to epoxy resin compositions, encapsulants, conductive materials, thermally conductive materials, insulating materials, adhesives for camera modules, structural adhesives, matrix resins for fiber-reinforced plastics, impregnation adhesives, interlayer insulating films, film-type solder resists, encapsulation sheets, conductive films, anisotropic conductive films, and thermally conductive films.

[0002] Traditionally, epoxy resins have been used in a wide range of applications, including insulating materials, sealing materials, adhesives, conductive materials, matrix resins for fiber-reinforced plastics, and impregnation and fixing agents for motor coils in electrical and electronic components.

[0003] In particular, the demands on electronic devices are diverse, including miniaturization, increased functionality, weight reduction, and multi-functionality. In semiconductor chip mounting technology, further miniaturization, miniaturization, and density improvements are being made through the reduction of the electrode pad pitch and pad pitch. Consequently, further improvements are required regarding the heat resistance and adhesive strength of surrounding components.

[0004] On the other hand, in order to improve the reliability of circuit connections or to reduce the weight of mobile devices, it is sometimes necessary to use materials with low heat resistance. Furthermore, in light of various requirements such as significantly improving productivity, there is a demand for higher potential in one-component epoxy resin compositions used as connection materials for electronic devices.

[0005] For example, epoxy resin compositions containing a curing agent whose latent properties are exhibited through microencapsulation have been proposed conventionally (see, for example, Patent Document 1).

[0006] On the other hand, structural adhesives are widely used as bonding agents for metal components in a wide range of fields, including automobiles, ships, aerospace, civil engineering, and construction. In recent years, in the automotive sector in particular, epoxy resin adhesives have come to be widely used during vehicle assembly as a replacement for or to reinforce conventional bonding technologies such as welding, bolts and nuts, and rivets. Because these epoxy resin adhesives are easy to handle, the emergence of one-component epoxy resin adhesives is desired, and adhesives using imidazole compounds as latent curing agents are being offered.

[0007] For example, Patent Document 2 discloses an epoxy resin composition for structural adhesives, comprising an epoxy resin and a curing agent component, wherein when particle gauge measurement is performed before and after 30 days under conditions of 30°C and 90 RH, the difference in the number of particles of 100 μm or more is 20 or less.

[0008] International Publication No. 2007 / 037378, Japanese Patent Publication No. 2019-147896

[0009] However, epoxy resin compositions like the one described in Patent Document 1 still have room for improvement in terms of achieving both the suppression of bubble generation during coating and adhesion.

[0010] Furthermore, the structural adhesives mentioned above may be transported or stored in environments exceeding 50°C. It is required that the viscosity remains below a certain level even after storage in such environments, and that the peel strength does not decrease. Conventional epoxy resin compositions described in Patent Document 2 have not solved these problems, and challenges remain.

[0011] The present invention has been made in view of the above problems, and aims to provide an epoxy resin composition, etc., that achieves both suppression of bubble generation and adhesion. Furthermore, a preferred embodiment of the present invention aims to provide a composition, etc., that has excellent storage stability in an environment of 50°C and improved peel strength.

[0012] As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the following technical means, and have completed the present invention. That is, the present invention is as follows.

[0013] <1> An epoxy resin composition comprising an epoxy resin (A) and a curing agent (B), wherein in an infrared absorption spectrum obtained when the epoxy resin composition is measured by infrared spectroscopy, 880 to 950 cm －１ , the maximum peak intensity (P1) in the range of 2200 to 2350 cm －１ , the value of the ratio (P2 / P1) to the maximum peak intensity (P2) in the range of 0.005 to 0.2 inclusive. An epoxy resin composition. <2> The epoxy resin composition according to <1>, further comprising a compound represented by the following formula (1). (In formula (1), R １ to R ９ each independently represent a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a hetero atom, or a substituent containing a halogen atom. Further, R ５ to R ９ may be a fused ring compound in which any one selected from the group exists on the same ring. ) <3> The epoxy resin composition according to <2>, wherein R １ in the formula (1) is a hydroxy group. <4> R ２ , R ３ and R ４ are hydrogen atoms, the epoxy resin composition according to <2> or <3>. <5> The epoxy resin (A) comprises a compound represented by the following formula (2), a compound represented by the following formula (3), a compound represented by the following formula (4), and a compound represented by the following formula (5), when the composition is measured by liquid chromatography, when the area of a peak attributed to the compound represented by the formula (2) is taken as 100, the area of a peak attributed to the compound represented by the formula (3) is 0.4 to 3.5, the area of a peak attributed to the compound represented by the formula (4) is 4 to 12, and the area of a peak attributed to the compound represented by the formula (5) is 2 to 8, the epoxy resin composition according to any one of <1> to <4>. <6> A composition comprising an epoxy resin (A) and a curing agent (B), wherein the epoxy resin (A) comprises the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5), when the composition is measured by liquid chromatography, when the area of the peak attributed to the compound represented by formula (2) is taken as 100, the area of the peak attributed to the compound represented by formula (3) is 0.4 to 3.5, the area of the peak attributed to the compound represented by formula (4) is 5 to 11, and the area of the peak attributed to the compound represented by formula (5) is 2 to 8, the epoxy resin composition according to <5>. <7> The epoxy resin composition according to <1>, wherein the epoxy resin (A) comprises a compound represented by the following formula (6) and a compound represented by the following formula (7), when the composition is measured by liquid chromatography, the ratio of the area of the peak attributed to the compound represented by the following formula (6) to the area of the peak attributed to the compound represented by the following formula (7) is 95 to 99:1 to 5. <8> The epoxy resin composition according to any one of <1> to <7>, wherein the curing agent (B) comprises an amine compound. <9> The epoxy resin composition according to any one of <1> to <8>, wherein the curing agent (B) comprises an imidazole compound. <10> The epoxy resin composition according to any one of <1> to <9>, wherein the curing agent (B) comprises a compound represented by the following formula (8). <11> The epoxy resin composition according to any one of <1> to <10>, wherein the curing agent (B) comprises at least one selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, and a compound of formula (8), the compound represented by formula (2) comprises a compound represented by the following formula (6) and a compound represented by the following formula (7), when the composition is measured by liquid chromatography, the ratio of the area of the peak attributed to the compound represented by the following formula (6) to the area of the peak attributed to the compound represented by the following formula (7) is 95 to 99:1 to 5. <12> The epoxy resin composition according to any one of <1> to <11>, wherein the epoxy resin (A) comprises the following formula (9) and a phenol novolac type epoxy resin, and when the composition is measured by liquid chromatography, the area of ​​the peak attributed to the following formula (9) is set to 100, and the area of ​​the peak attributed to the phenol novolac type epoxy resin is 0.01 to 10. <13> The epoxy resin composition according to any one of <1> to <12>, wherein the curing agent (B) comprises a encapsulated curing agent. <14> The epoxy resin composition according to any one of <1> to <13>, wherein the content of the curing agent (B) is 20 to 60% by mass relative to the total amount of the epoxy resin (A) and the curing agent (B). <15> A sealing material comprising the epoxy resin composition according to any one of <1> to <14>. <16> A conductive material comprising the epoxy resin composition according to any one of <1> to <14>. <17> A thermally conductive material comprising the epoxy resin composition according to any one of <1> to <14>. <18> An insulating material comprising the epoxy resin composition according to any one of <1> to <14>. <19> An adhesive for camera modules comprising the epoxy resin composition according to any one of <1> to <14>. <20> A structural adhesive comprising the epoxy resin composition according to any one of <1> to <14>. <21> A matrix resin for fiber-reinforced plastics comprising the epoxy resin composition described in any of <1> to <14>. <22> An impregnation adhesive comprising the epoxy resin composition described in any of <1> to <14>. <23> An interlayer insulating film comprising the epoxy resin composition described in any of <1> to <14>. <24> A film-type solder resist comprising the epoxy resin composition described in any of <1> to <14>. <25> A sealing sheet comprising the epoxy resin composition described in any of <1> to <14>. <26> A conductive film comprising the epoxy resin composition described in any of <1> to <14>. <27> An anisotropic conductive film comprising the epoxy resin composition described in any of <1> to <14>. <28> A thermally conductive film comprising the epoxy resin composition described in any of <1> to <14>.

[0014] According to one aspect of the present invention, an epoxy resin composition or the like that achieves both suppression of bubble generation and adhesiveness can be provided. Further, according to a preferred aspect of the present invention, a composition or the like that has excellent storage stability in an environment of 50°C and has improved peel strength can be provided.

[0015] Hereinafter, an embodiment of the present invention (hereinafter also referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following present embodiment, and can be implemented with various modifications within the scope of the gist thereof.

[0016] In the present specification, the term "(meth)acrylic" means "acrylic" and "methacrylic" corresponding thereto. In addition, unless otherwise specified, the term "~" in the present specification means that the numerical values at both ends thereof are included as the upper limit and the lower limit.

[0017] (Epoxy Resin Composition) The epoxy resin composition of the present embodiment includes an epoxy resin (A) and a curing agent (B), and in an infrared absorption spectrum measured by infrared spectroscopy, 880 to 950 cm －１ the ratio (P2 / P1) of the maximum peak intensity (P1) in the range to the maximum peak intensity (P2) in the range of 2200 to 2350 cm －１ is 0.005 or more and 0.2 or less.

[0018] With the above configuration, the epoxy resin composition of the present embodiment can achieve both suppression of bubble generation and adhesiveness. Although the mechanism is not limited to the following, it is presumed as follows. In the infrared absorption spectrum obtained by measuring the epoxy resin composition of the present embodiment by infrared spectroscopy, 880 to 950 cm －１ the peak in the range is a peak derived from epoxy groups in the epoxy resin composition, and 2200 to 2350 cm －１The peaks within this range are peaks originating from the isocyanate groups in the epoxy resin composition. In other words, by having the ratio of the peak intensity originating from the isocyanate groups to the peak intensity originating from the epoxy groups within the above range, the epoxy resin composition of this embodiment can achieve both suppression of bubble generation and adhesion. More specifically, if the peak intensity of the isocyanate groups is higher than that of the epoxy groups, the isocyanate groups of the epoxy resin composition react with moisture in the air, generating carbon dioxide and causing bubbles, while the adhesion to substrates having hydrophilic groups on the surface improves. Conversely, if the peak intensity of the isocyanate groups is lower than that of the epoxy groups, bubble generation can be suppressed, but adhesion decreases. By having the peak intensity ratio of the epoxy groups to the isocyanate groups within the above range, an excellent balance is achieved, resulting in the ability to achieve both suppression of bubble generation and adhesion.

[0019] From the above perspective, in the infrared absorption spectrum measured by infrared spectroscopy, 880–950 cm⁻¹ －１ The maximum peak intensity (P1) in the range of 2200–2350 cm －１ The ratio (P2 / P1) of the maximum peak intensity (P2) within the specified range is preferably 0.01 to 0.15, more preferably 0.02 to 0.12, and even more preferably 0.025 to 0.1. More specifically, infrared spectroscopy can be measured by the method described in the examples below.

[0020] In the epoxy resin composition of this embodiment, the value of the above ratio (P2 / P1) can be controlled by the manufacturing conditions of the curing agent (B) described later and the mixing ratio of the epoxy resin (A) and the curing agent (B). Specifically, the above ratio (P2 / P1) can be controlled by controlling the humidity and time when removing the solvent after reacting the compound containing an isocyanate group with the curing agent (B) in the solvent.

[0021] (Epoxy resin (A)) The epoxy resin composition of this embodiment contains epoxy resin (A). Epoxy resin (A) is not particularly limited, and various known types can be appropriately selected and used. Epoxy resin (A) may be used alone or in combination of two or more types.

[0022] The epoxy resin (A) is not limited to the following, but examples include bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, tetrabromobisphenol A type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, tetrabromobiphenyl type epoxy resin, diphenyl ether type epoxy resin, benzophenone type epoxy resin, phenylbenzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin, diphenyl sulfone type epoxy resin, diphenyl disulfide type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcinol type epoxy resin, methylresorcinol type epoxy resin, catechol type epoxy resin, N,N-diglycidylaniline type epoxy resin, and N,N-diglycidyl-o-toluidine type epoxy resin.

[0023] Furthermore, epoxy resin (A) includes trifunctional epoxy resins such as triazine-type epoxy resin and aminophenol-type epoxy resin; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane-type epoxy resin and diaminobenzene-type epoxy resin; polyfunctional epoxy resins such as phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, triphenylmethane-type epoxy resin, tetraphenylethane-type epoxy resin, dicyclopentadiene-type epoxy resin, naphthol aralkyl-type epoxy resin, and brominated phenol novolac-type epoxy resin; (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, polytetramethylene ether glycol diglycidyl ether, glyc Examples include diglycidyl acyclic aliphatic epoxy resins such as serine diglycidyl ether and neopentyl glycol diglycidyl ether; triglycidyl acyclic aliphatic epoxy resins such as trimethylolpropane triglycidyl ether and glycerin triglycidyl ether; alicyclic epoxy resins such as vinyl (3,4-cyclohexene) dioxide and 2-(3,4-epoxycyclohexyl)-5,1-spiro-(3,4-epoxycyclohexyl)-m-dioxane; cyclohexane-type diglycidyl ethers such as cyclohexanedimethanol diglycidyl ether, dicyclopentadiene-type diglycidyl ether, and cyclic aliphatic epoxy resins such as tetraglycidylbis(aminomethyl)cyclohexane; hydantoin-type epoxy resins such as 1,3-diglycidyl-5-methyl-5-ethylhydantoin; and epoxy resins having a silicone skeleton such as 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane.

[0024] Furthermore, as epoxy resin (A), the following are available: 2-ethylhexylglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, hydrogenated bisphenol A epoxy resin, silicone-modified epoxy resin, (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, butanediol diglycidyl ether, trimethylolpropane diglycidyl ether, polytetramethylene A Glycerol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexane type diglycidyl ether, dicyclopentadiene type diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, vinyl (3,4-cyclohexene) dioxide, 2-(3,4-epoxycyclohexyl)-5,1-spiro-(3,4-epoxycyclohexyl)-m-dioxane, tetraglycidyl bis(aminomethyl)cyclo Hexane-like glycidylamine type epoxy resin, 1,3-diglycidyl-5-methyl-5-ethylhydantoin type epoxy resin, 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane type epoxy resin, phenyl glycidyl ether, cresyl glycidyl ether, p-s-butylphenyl glycidyl ether, styrene oxide, p-tert-butylphenyl glycidyl ether, o-phenylphenol glycidyl ether, p-phenylphenol glycidyl ether, N Examples include aliphatic epoxy resins and alicyclic epoxy resins that can also be used as reactive diluents for glycidylphthalimide, n-butylglycidyl ether, 2-ethylhexylglycidyl ether, α-pinene oxide, allylglycidyl ether, 1-vinyl-3,4-epoxycyclohexane, 1,2-epoxy-4-(2-methyloxyranyl)-1-methylcyclohexane, 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, glycidyl neodecanoate, etc.

[0025] Among these, it is preferable that epoxy resin (A) includes bisphenol A type epoxy resin and / or bisphenol F type epoxy resin and / or naphthalene type epoxy resin. When epoxy resin (A) includes the above epoxy resins, the storage stability of the epoxy resin composition and the mechanical strength of the cured product tend to be excellent.

[0026] The content of epoxy resin (A) is not particularly limited, but is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 75% by mass, relative to the total amount of the epoxy resin composition. When the content of epoxy resin (A) is within the above range, the fluidity of the epoxy resin composition and the mechanical strength of the cured product tend to be excellent.

[0027] The content of epoxy resin (A) is not particularly limited, but is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 75% by mass, relative to the total amount of epoxy resin (A) and curing agent (B). When the content of epoxy resin (A) is within the above range, the suppression of bubble generation and adhesion tend to be better.

[0028] The epoxy resin (A) may contain the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5).

[0029] The compounds represented by formulas (2), (4), and (5) above can be obtained by known synthesis methods.

[0030] Known synthesis methods include reacting bisphenol A with epichlorohydrin in the presence of an alkaline compound.

[0031] In the reaction between bisphenol A and epichlorohydrin, the amount of epichlorohydrin is preferably 2 to 15 equivalents per equivalent of hydroxyl groups of bisphenol A.

[0032] Examples of alkaline compounds include sodium hydroxide, potassium hydroxide, barium hydroxide, and potassium carbonate. These may be used individually or in combination of two or more. The state of the alkaline compound is not particularly limited and may be solid, liquid, or aqueous solution. The amount of alkaline compound added is preferably 0.7 to 2 equivalents per equivalent of hydroxyl groups of bisphenol A.

[0033] The reaction temperature is preferably 80 to 140°C, the time required to add the alkaline compound is preferably 1 to 5 hours, and the reaction time after addition is preferably 1 to 10 hours.

[0034] Methods for adjusting the ratios of the compounds represented by formulas (2), (4), and (5) during synthesis include adjusting the amount of epichlorohydrin per equivalent of hydroxyl group of bisphenol A, adjusting the rate of addition of alkaline compounds, and adjusting the reaction temperature. For example, to increase the proportion of the compounds represented by formulas (4) and (5), the amount of epichlorohydrin can be reduced.

[0035] Furthermore, distillation is a method for obtaining the compound represented by formula (2) in high purity, and thin-film distillation is preferred. Known conditions can be applied to the distillation conditions.

[0036] The compound represented by formula (3) can be generated in the reaction system when reacting the aforementioned bisphenol A and epichlorohydrin in the presence of an alkaline compound to obtain the compounds represented by formulas (2), (4), and (5).

[0037] Examples of epoxy compounds containing the compound represented by formula (2) above include AER250 manufactured by Asahi Kasei Corporation, and jER(registered trademark)-828, 828US, and 834 manufactured by Mitsubishi Chemical Corporation, which are commercially available products.

[0038] Examples of epoxy compounds containing the compound represented by the above formula (3) include bisphenol A (2,3-dihydroxypropyl) glycidyl ether manufactured by Sigma-Aldrich.

[0039] Examples of epoxy compounds containing the compound represented by formula (4) above include AER250 from Asahi Kasei Corporation and jER(registered trademark)-828, 828US, and 834 from Mitsubishi Chemical Corporation, which are commercially available products.

[0040] Examples of epoxy compounds containing the compound represented by formula (5) above include AER250 from Asahi Kasei Corporation and jER(registered trademark)-828, 828US, and 834 from Mitsubishi Chemical Corporation, which are commercially available products.

[0041] The composition of this embodiment may contain, in addition to the compounds described in (2) to (5) above, other epoxy resins as epoxy resin (A). The other epoxy resins are not particularly limited, and various known ones can be appropriately selected and used. The other epoxy resins may be used individually or in combination of two or more.

[0042] Other epoxy compounds are not limited to those listed below, but examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, tetrabromobisphenol A type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, tetrabromobiphenyl type epoxy resin, diphenyl ether type epoxy resin, benzophenone type epoxy resin, phenylbenzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin, diphenyl sulfone type epoxy resin, diphenyl disulfide type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcinol type epoxy resin, methylresorcinol type epoxy resin, catechol type epoxy resin, N,N-diglycidylaniline type epoxy resin, N,N-diglycidyl-o-toluidine type epoxy resin, and other bifunctional epoxy resins, excluding compounds that fall under the compounds represented in (1) to (5) above.

[0043] Other epoxy compounds include trifunctional epoxy resins such as triazine-type epoxy resins and aminophenol-type epoxy resins; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane-type epoxy resins and diaminobenzene-type epoxy resins; polyfunctional epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, triphenylmethane-type epoxy resins, tetraphenylethane-type epoxy resins, dicyclopentadiene-type epoxy resins, naphthol aralkyl-type epoxy resins, and brominated phenol novolac-type epoxy resins; (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, polytetramethylene ether glycol diglycidyl ether, and glycidyl ether. Examples include diglycidyl acyclic aliphatic epoxy resins such as serine diglycidyl ether and neopentyl glycol diglycidyl ether; triglycidyl acyclic aliphatic epoxy resins such as trimethylolpropane triglycidyl ether and glycerin triglycidyl ether; alicyclic epoxy resins such as vinyl (3,4-cyclohexene) dioxide and 2-(3,4-epoxycyclohexyl)-5,1-spiro-(3,4-epoxycyclohexyl)-m-dioxane; cyclohexane-type diglycidyl ethers such as cyclohexanedimethanol diglycidyl ether, dicyclopentadiene-type diglycidyl ether, and cyclic aliphatic epoxy resins such as tetraglycidylbis(aminomethyl)cyclohexane; hydantoin-type epoxy resins such as 1,3-diglycidyl-5-methyl-5-ethylhydantoin; and epoxy resins having a silicone skeleton such as 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane.

[0044] Furthermore, other epoxy compounds include 2-ethylhexylglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, hydrogenated bisphenol A epoxy resin, silicone-modified epoxy resin, (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, butanediol diglycidyl ether, trimethylolpropane diglycidyl ether, and polytetramethylene A Glycerol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexane type diglycidyl ether, dicyclopentadiene type diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, vinyl (3,4-cyclohexene) dioxide, 2-(3,4-epoxycyclohexyl)-5,1-spiro-(3,4-epoxycyclohexyl)-m-dioxane, tetraglycidyl bis(aminomethyl)cyclo Hexane-like glycidylamine type epoxy resin, 1,3-diglycidyl-5-methyl-5-ethylhydantoin type epoxy resin, 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane type epoxy resin, phenyl glycidyl ether, cresyl glycidyl ether, p-s-butylphenyl glycidyl ether, styrene oxide, p-tert-butylphenyl glycidyl ether, o-phenylphenol glycidyl ether, p-phenylphenol glycidyl ether, N Examples include aliphatic epoxy resins and alicyclic epoxy resins that can also be used as reactive diluents for glycidylphthalimide, n-butylglycidyl ether, 2-ethylhexylglycidyl ether, α-pinene oxide, allylglycidyl ether, 1-vinyl-3,4-epoxycyclohexane, 1,2-epoxy-4-(2-methyloxyranyl)-1-methylcyclohexane, 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, glycidyl neodecanoate, etc.

[0045] Among these, if the composition of this embodiment contains other epoxy compounds, it is preferable that it contains a bisphenol F type epoxy resin and / or a naphthalene type epoxy resin.

[0046] In one embodiment of the composition of this embodiment, the content of epoxy compound (A) is not particularly limited, but from the viewpoint of excellent storage stability and improved peel strength, it is preferably 35 to 95% by mass, more preferably 40 to 90% by mass, and even more preferably 45 to 85% by mass, relative to the total amount of the composition.

[0047] In one embodiment of the composition of this embodiment, the total content of the compounds represented by formulas (1) to (4) is not particularly limited, but from the viewpoint of having excellent storage stability at 50°C and suppressing a decrease in peel strength, it is preferably 25 to 95% by mass, more preferably 30 to 90% by mass, and even more preferably 35 to 85% by mass, relative to the total amount of the composition.

[0048] In one embodiment of the composition of this embodiment, if other epoxy compounds are included, and if bisphenol F type epoxy resin and / or naphthalene type epoxy resin are included, the content thereof is not particularly limited, but from the viewpoint of having excellent storage stability in an environment of 50°C and suppressing a decrease in peel strength, it is preferably 15 to 45% by mass, more preferably 20 to 40% by mass, and even more preferably 25 to 35% by mass, based on the total amount of the composition.

[0049] The epoxy resin (A) contains the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5). From the viewpoint of suppressing the decrease in storage stability and T-peel strength in a 50°C environment, when the composition is measured by liquid chromatography, when the area of ​​the peak attributed to the compound represented by formula (2) is set to 100, the area of ​​the peak attributed to the compound represented by formula (3) is preferably 0.4 to 10, more preferably 0.4 to 6, and even more preferably 0.4 to 3.5. The area of ​​the peak attributed to the compound represented by formula (4) is preferably 4 to 12, more preferably 4 to 11, and even more preferably 5 to 11. The area of ​​the peak attributed to the compound represented by formula (5) is preferably 2 to 8, more preferably 2 to 7, and even more preferably 2 to 6. Furthermore, Asahi Kasei's AER250, AER260, Mitsubishi Chemical's jER828, jER828US, YL980, DIC's EXA850, Olin's DER383J, DER331, and Changchun's BE-186EL are not epoxy resins in which, when the area of ​​the peak attributed to the compound represented by formula (2) is set to 100, the area of ​​the peak attributed to the compound represented by formula (3) is 0.4 to 10, the area of ​​the peak attributed to the compound represented by formula (4) is 4 to 12, and the area of ​​the peak attributed to the compound represented by formula (5) is 2 to 8.

[0050] The mechanism by which the composition of this embodiment, by containing the compounds of formulas (2) to (5) within the specified range, can suppress the decrease in T-peel strength and storage stability at a 50°C environment is not limited to the following, but is presumed to be as follows. By containing the compounds of formulas (2) to (5) within the specified range, the composition of this embodiment suppresses the aggregation of the compound represented by formula (2) at a 50°C storage environment, maintains the uniformity of the epoxy resin (A) in the composition, and adjusts the amount of polar groups derived from each of the compounds represented by formulas (3) to (5) to an appropriate range that moderately suppresses the reactivity between the epoxy resin (A) and the curing agent (B) at a 50°C storage environment, while allowing it to be fully expressed during heat curing. Here, since the compounds represented by formulas (3), (4), and (5) have different effects on the reactivity and stability of the composition, it is important that each compound is adjusted to a relatively specific range. As a result, it is possible to achieve excellent storage stability at a 50°C environment and suppress the decrease in peel strength. On the other hand, if the reaction between the epoxy resin (A) and the curing agent (B) proceeds excessively due to an excess of the compound represented by formula (3), or if the compounds represented by formulas (4) and (5) are in excess, the viscosity of the composition after storage at 50°C becomes significantly higher.

[0051] From the viewpoint of suppressing aggregation of the compound represented by formula (2) in the composition, it is preferable that the compound represented by formula (2) includes the compound represented by the following formula (6) and the compound represented by the following formula (7).

[0052]

[0053] In the composition of this embodiment, when the compound represented by formula (2) includes the compound represented by formula (6) and the compound represented by formula (7), the ratio of the peak area attributed to the compound represented by formula (6) to the peak area attributed to the compound represented by formula (7) when measured by liquid chromatography is not particularly limited, but from the above viewpoint, it is preferably 95 to 99:1 to 5, with the sum being 100, and more preferably 96 to 98:2 to 4.

[0054] In this case, the viscosity of the composition of this embodiment at 25°C is not particularly limited, but from the viewpoint of ease of handling during work, it is preferably 1 to 1000 Pa·s, more preferably 5 to 800 Pa·s, and even more preferably 10 to 600 Pa·s. The viscosity at 25°C can be measured using an E-type viscometer. The viscosity of the composition of this embodiment at 25°C can be adjusted by the type or amount of epoxy compound (A) or amine compound (B) used.

[0055] The epoxy resin (A) may contain the compound represented by the above formula (9) and a phenol novolac type epoxy resin.

[0056] The epoxy resin (A) contains the compound represented by formula (9) and a phenol novolac type epoxy resin. When the composition is measured by liquid chromatography, the area of ​​the peak attributed to the compound represented by formula (9) is set to 100, while the area of ​​the peak attributed to the phenol novolac type epoxy resin is 0.01 to 10. The above configuration of epoxy resin (A) allows for high heat resistance to be imparted to the cured product.

[0057] From the above viewpoint, when the composition of this embodiment is measured by liquid chromatography, if the area of ​​the peak attributed to the compound represented by formula (9) is set to 100, the area of ​​the peak attributed to the phenol novolac type epoxy resin is preferably 0.01 to 10, more preferably 0.02 to 9, and even more preferably 0.03 to 8.

[0058] (Curing agent (B)) The epoxy resin composition of this embodiment contains a curing agent (B). The curing agent (B) may be used alone or in combination of two or more types.

[0059] The curing agent (B) is not particularly limited, but examples include amine-based curing agents, amide-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, active ester-based curing agents, and thiol-based curing agents. Among these, amine-based curing agents containing amine compounds are preferred. The curing agent (B) preferably contains an amine compound, and examples include low molecular weight amine compounds, amine adduct-based compounds, modified polyamine-based compounds, aliphatic polyamine-based compounds, heterocyclic polyamine-based compounds, alicyclic polyamine-based compounds, aromatic amine-based compounds, and polyamide amine-based compounds. The amine compound (B) may contain an amine compound that is solid at 25°C or a liquid amine compound, but from the viewpoint of storage stability, it is preferable to contain an amine compound that is solid at 25°C.

[0060] Low molecular weight amine compounds include, but are not limited to, compounds that do not contain tertiary amines such as methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophoronediamine, aniline, toluidine, diaminodiphenylmethane, diaminodiphenylsulfone, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine, dicyclohexylamine, piperidine, piperidone, diphenylamine, phenylmethylamine, phenylethylamine, etc.; 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol Amino alcohols such as tanol, 1-butoxymethyl-2-dimethylaminoethanol, methyldiethanolamine, triethanolamine, and N-β-hydroxyethylmorpholine; aminophenols such as 2-(dimethylaminomethyl)phenol and 2,4,6-tris(dimethylaminomethyl)phenol; imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, and 2-heptazole. Imidazoles such as tadecylimidazole, 2-phenylimidazole, 1-aminoethyl-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazole, and 1-(2-hydroxy-3-butoxypropyl)-2-ethyl-4-methylimidazole;1-(2-hydroxy-3-phenoxypropyl)-2-phenylimidazoline, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazoline, 2-methylimidazoline, 2,4-dimethylimidazoline, 2-ethylimidazoline, 2-ethyl-4-methylimidazoline, 2-benzylimidazoline, 2-phenylimidazoline, 2-(o-tolyl)-imidazoline, tetramethylene-bis-imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-imidazoline, 1,3,3-trimethyl-1,4-tetramethylene Imidazolins such as -bis-imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 1,3,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 1,2-phenylene-bis-imidazoline, 1,3-phenylene-bis-imidazoline, 1,4-phenylene-bis-imidazoline, 1,4-phenylene-bis-4-methylimidazoline, etc.; trimethylamine, triethylamine, benzyldimethylamine, N,N-dimethylethylamine, N,N-dimethylbutylamine, N,N -Dimethyldecylamine, N,N-dimethyl-m-toluidine, N,N-dimethyl-p-toluidine, 2,6,10-trimethyl-2,6,10-triazaundane, N,N'-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1-azabicyclo[2.2.2]octane-3-one, 1,8-diazabicyclo(5,4,0)-undecene-7, 1,5-diazabicyclo(4,3,0)-nonene-5, hexamethylenetetramine, dimethylaminopropylamine, diethylaminopropylamine, dipropyl Tertiary aminoamines such as minopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, dipropylaminoethylamine, dibutylaminoethylamine, N-methylpiperazine, N-aminoethylpiperazine, diethylaminoethylpiperazine, 2-dimethylaminopyridine, and 4-dimethylaminopyridine; aminomercaptans such as 2-dimethylaminoethanethiol, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptopyridine, and 4-mercaptopyridine;Examples include aminocarboxylic acids such as N,N-dimethylaminobenzoic acid, N,N-dimethylglycine, nicotinic acid, isonicotinic acid, and picolinic acid; and aminohydrazides such as N,N-dimethylglycine hydrazide, nicotinic acid hydrazide, and isonicotinic acid hydrazide. These may be used individually or in combination of two or more. Among these, imidazole compounds are preferred. The compound having an imidazole structure may be the low molecular weight amine compound having an imidazole structure described above, or it may be an imidazole-based amine adduct compound having an imidazole structure, which is a reaction product of imidazoles with one or more of carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins. The imidazole-based amine adduct preferably includes a reaction product of imidazoles and epoxy resins, or a reaction product of imidazoles with bisphenol A type epoxy resin and phenoxy resin with high molecular weight bisphenol A and epichlorohydrin. In the composition of this embodiment, the amine compound (B) contains a compound having an imidazole structure, which tends to result in excellent storage stability at 50°C and suppression of a decrease in peel strength.

[0061] The amine adduct compounds are not limited to those listed below, but examples include compounds obtained by the reaction of one or more of the following: carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins, with the low molecular weight amine compounds mentioned above. In this embodiment, the amine adduct compound preferably includes an imidazole-based amine adduct compound. The imidazole-based amine adduct may be a reaction product of imidazoles with one or more of the following: carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins. The imidazole-based amine adduct compound preferably includes a reaction product of imidazoles and epoxy resins, and from the viewpoint of mechanical strength, it is particularly preferable to include a reaction product of imidazole and bisphenol-type epoxy resins.

[0062] The curing agent (B) of this embodiment preferably contains a compound represented by the following formula (8) among the above-mentioned amine adduct compounds. By containing a compound represented by the following formula (8), the melt viscosity of the curing agent during heating is reduced, and the curing agent diffuses uniformly in a short time, which tends to result in better adhesion.

[0063]

[0064] From the viewpoint of having excellent storage stability at 50°C and being able to suppress the decrease in peel strength, it is preferable that the compound having an imidazole structure includes at least one selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, and the compound represented by the above formula (8).

[0065] When the curing agent (B) contains at least one selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, and the compound represented by formula (8) above, the content thereof is preferably 0.0001% by mass or more and 20% by mass or less, more preferably 0.001% by mass or more and 18% by mass or less, even more preferably 0.002% by mass or more and 16% by mass or less, even more preferably 0.003% by mass or more and 14% by mass or less, and particularly preferably 0.004% by mass or more and 12% by mass or less, based on the total amount of the curing agent (B).

[0066] Examples of carboxylic acid compounds include, but are not limited to, succinic acid, adipic acid, sebacic acid, phthalic acid, and dimer acid.

[0067] Examples of sulfonic acid compounds include, but are not limited to, ethanesulfonic acid and p-toluenesulfonic acid.

[0068] Examples of urea compounds include, but are not limited to, urea, methylurea, dimethylurea, ethylurea, and t-butylurea.

[0069] Examples of isocyanate compounds include, but are not limited to, aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, aliphatic triisocyanates, and polyisocyanates. Examples of aliphatic diisocyanates include, but are not limited to, ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Examples of alicyclic diisocyanates include, but are not limited to, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanatocyclohexane, 1,3-bis(isocyanatomethyl)-cyclohexane, and 1,3-bis(2-isocyanatopropyl-2-yl)-cyclohexane. Aromatic diisocyanates include, but are not limited to, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, and 1,5-naphthalene diisocyanate. Aliphatic triisocyanates include, but are not limited to, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, and 1,3,6-triisocyanate methylhexane. Polyisocyanates include, but are not limited to, polymethylene polyphenyl polyisocyanate and polyisocyanates derived from the diisocyanate compounds. Polyisocyanates derived from the diisocyanate compounds include isocyanurate-type polyisocyanates, burette-type polyisocyanates, urethane-type polyisocyanates, allohanate-type polyisocyanates, and carbodiimide-type polyisocyanates.

[0070] The epoxy resin is not limited to the following, but examples include bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, tetrabromobisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, tetrabromobiphenyl type epoxy resin, diphenyl ether type epoxy resin, benzophenone type epoxy resin, phenylbenzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin, diphenyl sulfone type epoxy resin, diphenyl disulfide type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcinol type epoxy resin, methylresorcinol type epoxy resin, catechol type epoxy resin, etc. Examples include xylic resins; trifunctional epoxy resins such as N,N-diglycidylaminobenzene type epoxy resins and triazine type epoxy resins; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane type epoxy resins and diaminobenzene type epoxy resins; polyfunctional epoxy resins such as phenol novolac type epoxy resins, cresol novolac type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene type epoxy resins, naphthol aralkyl type epoxy resins, and brominated phenol novolac type epoxy resins; monoepoxy compounds such as butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, paraxylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexoate, and glycidyl benzoate; and alicyclic epoxy resins. These may be used individually or in combination of two or more types.

[0071] Examples of amide-based curing agents include, but are not limited to, dicyandiamide and its derivatives, such as guanidine compounds, or compounds obtained by adding an acid anhydride to an amine compound, as well as hydrazide compounds. Examples of hydrazide compounds include, but are not limited to, succinate dihydrazide, adipic acid dihydrazide, phthalate dihydrazide, isophthalate dihydrazide, terephthalate dihydrazide, p-oxybenzoic acid hydrazide, salicylic acid hydrazide, phenylaminopropionic acid hydrazide, maleate dihydrazide, etc. Examples of guanidine compounds include, but are not limited to, dicyandiamide, methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, toluylguanidine, etc.

[0072] Examples of phenolic curing agents include, but are not limited to, phenol novolac resins, cresol novolac resins, phenol aralkyl resins, cresol aralkyl resins, naphthol aralkyl resins, biphenyl-modified phenol resins, biphenyl-modified phenol aralkyl resins, dicyclopentadiene-modified phenol resins, aminotriazine-modified phenol resins, naphthol novolac resins, naphthol-phenol cocondensed novolac resins, naphthol-cresol cocondensed novolac resins, and allyl acrylic phenol resins.

[0073] Examples of acid anhydride-based curing agents include, but are not limited to, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0074] The active ester curing agent is not particularly limited as long as it functions as a curing agent for epoxy resins and has an active ester, but compounds having two or more active ester groups in one molecule are preferred. From the viewpoint of heat resistance, etc., active ester compounds obtained from reacting a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound are more preferred, and active ester compounds obtained from reacting a carboxylic acid compound with one or more selected from phenol compounds, naphthol compounds, and thiol compounds are even more preferred. The active ester compound constituting the active ester curing agent may be one or more in combination. As the active ester compound, the active ester compound disclosed in Japanese Patent Application Publication No. 2004-277460 may be used, or a commercially available one may be used. As commercially available active ester compounds, for example, those containing a dicyclopentadienyldiphenol structure, acetylated phenol novolacs, and benzoylated phenol novolacs are preferred, and those containing a dicyclopentadienyldiphenol structure are particularly preferred. Examples of products containing a dicyclopentadienyldiphenol structure include EXB9451, EXB9460, EXB9460S, HPC-8000-65T (manufactured by DIC Corporation), DC808 (manufactured by Japan Epoxy Resin Co., Ltd.) as an acetylated phenol novolac, and YLH1026 (manufactured by Japan Epoxy Resin Co., Ltd.) as a benzoylated phenol novolac.

[0075] Thiol-based curing agents include, but are not limited to, trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate). Tris(3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, pentaerythritol trippropanthol, pentaerythritol tetrapropanthol, 1,3,4,6-tetrakis(2-mercaptoethyl) glycoluryl, (1,3,4,6-tetrakis(3-mercaptopropyl) glycoluryl, 1,3,4,6-tetrakis(mercaptopropyl) (Ptomethyl) glycoluryl, 1,3,4,6-tetrakis(mercaptomethyl)-3a-methylglycoluryl, 1,3,4,6-tetrakis(2-mercaptoethyl)-3a-methylglycoluryl, 1,3,4,6-tetrakis(3-mercaptopropyl)-3a-methylglycoluryl, 1,3,4,6-tetrakis(mercaptomethyl)-3a,6a-dimethylglycoluryl, 1,3,4,6-tetrakis(2-mercaptoethyl)-3 Examples include a,6a-dimethylglycoluryl, 1,3,4,6-tetrakis(3-mercaptopropyl)-3a,6a-dimethylglycoluryl, 1,3,4,6-tetrakis(mercaptomethyl)-3a,6a-diphenylglycoluryl, 1,3,4,6-tetrakis(2-mercaptoethyl)-3a,6a-diphenylglycoluryl, and 1,3,4,6-tetrakis(3-mercaptopropyl)-3a,6a-diphenylglycoluryl.

[0076] (Capsule-type curing agent) In this embodiment, from the viewpoint of suppressing bubble generation and providing better adhesion, it is preferable that the curing agent (B) has a core-shell structure in which the surface of the core (C) is covered with a shell (S), that is, it contains a capsule-type curing agent.

[0077] The presence of a encapsulated curing agent can be confirmed by staining the curing agent using the following method: Mix 10.6 mL of the main component (Quetol 812, manufactured by Nissin EM Co., Ltd.), 9.4 mL of the curing agent (Methyl nadic anhydride: MNA, manufactured by Nissin EM Co., Ltd.), and 0.34 mL of the reaction accelerator (2,4,6-Tris(dimethylaminomethyl)phenol, manufactured by Nissin EM Co., Ltd.: DMP-30), stir with a stirrer for 15 minutes, and then remove air bubbles by vacuum desorption to obtain an epoxy resin composition for staining. The curing agent of this embodiment is electron-stained by coexisting with ruthenium tetroxide for 10 minutes in a sealed and light-shielded container at room temperature and atmospheric pressure. Then, it is mixed with the aforementioned staining epoxy resin composition and cured at 40°C for 42 hours. An 80 nm section is prepared from the cured material containing embedded curing agent particles using an ultramicrotome. The section is then coexisted with osmium tetroxide for 2 hours in a sealed and light-shielded container at room temperature and atmospheric pressure to obtain an observation sample that has been electron-stained with osmium tetroxide vapor. An electron beam is irradiated onto the observation sample using a TEM, and the focus is adjusted to match the sample. An image is obtained by observation at an acceleration voltage of 120 kV and a magnification of 30,000 times. When the curing agent is microcapsule-type, layers with different brightness can be observed at the interface between the outermost core and the epoxy resin composition.

[0078] If the capsules containing the curing agent (B) are dispersed in another dispersion medium such as an epoxy compound or an acrylic compound, the capsules containing the curing agent (B) can be obtained by adding an organic solvent, separating the dispersion medium and capsules by centrifugation, collecting the capsules, and drying them. The organic solvents that can be used include those listed later as organic solvents.

[0079] (Shell (S)) The shell (S) is not particularly limited, but examples include layers containing resin or inorganic oxides. Examples of resins include epoxy resins, phenolic resins, polyester resins, polyethylene resins, nylon resins, polystyrene resins, and urethane resins. Among these, epoxy resins, phenolic resins, and urethane resins are preferred for the resin contained in the shell (S).

[0080] Examples of epoxy resins include, but are not limited to, the epoxy resins mentioned above.

[0081] Examples of phenolic resins include, but are not limited to, phenol-formaldehyde polycondensates, cresol-formaldehyde polycondensates, resorcinol-formaldehyde polycondensates, bisphenol A-formaldehyde polycondensates, and polyethylene polyamine-modified phenol-formaldehyde polycondensates.

[0082] Examples of polyester resins, though not limited to those listed below, include ethylene glycol-terephthalic acid-polypropylene glycol polycondensate, ethylene glycol-butylene glycol-terephthalic acid polycondensate, and terephthalic acid-ethylene glycol-polyethylene glycol polycondensate.

[0083] Polyethylene resins are not limited to the following, but examples include ethylene-propylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, and ethylene-vinyl acetate-acrylic acid copolymer.

[0084] Examples of nylon-based resins include, but are not limited to, adipic acid-hexamethylenediamine polycondensate, sebaciic acid-hexamethylenediamine polycondensate, and p-phenylenediamine-terephthalic acid polycondensate.

[0085] Examples of polystyrene resins include, but are not limited to, styrene-butadiene copolymers, styrene-butadiene-acrylonitrile copolymers, acrylonitrile-styrene-divinylbenzene copolymers, and styrene-propenyl alcohol copolymers.

[0086] Examples of urethane resins include, but are not limited to, isocyanate monomers such as butyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, phenyl isocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tolidine diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate, their condensates, or polycondensates of isocyanate monomers with monoalcohols or polyhydric alcohols. Among these, urethane resins that are addition products of monoalcohols or polyhydric alcohols with monoisocyanates or polyhydric isocyanates are preferred.

[0087] Examples of inorganic oxides include, but are not limited to, boron compounds such as boron oxide, silicon dioxide, and calcium oxide. Among these, boron oxide is preferred from the viewpoint of film stability and ease of breakdown during heating.

[0088] The shell (S) preferably contains a reaction product obtained from two or more raw materials selected from the group consisting of isocyanate compounds, active hydrogen compounds, epoxy resins, and amine compounds, from the viewpoint of suppressing bubble generation and providing superior adhesion. More preferably, it contains a reaction product obtained from isocyanate compounds and amine compounds. The compounds described above can be used as isocyanate compounds, epoxy resins, and amine compounds.

[0089] The active hydrogen compounds used in the reaction product are not limited to the following, but examples include water, compounds having at least one primary amino group and / or a secondary amino group, and compounds having at least one hydroxyl group. Furthermore, the active hydrogen compounds may be used individually or in combination of two or more.

[0090] Compounds having at least one primary amino group and / or secondary amino group include aliphatic amines, alicyclic amines, and aromatic amines. Aliphatic amines include, but are not limited to, alkylamines such as methylamine, ethylamine, propylamine, butylamine, and dibutylamine; alkylenediamines such as ethylenediamine, propylenediamine, butylenediamine, and hexamethylenediamine; polyalkylene polyamines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; and polyoxyalkylene polyamines such as polyoxypropylenediamine and polyoxyethylenediamine. Alicyclic amines include, but are not limited to, cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, and isophoronediamine. Aromatic amines include, but are not limited to, aniline, toluidine, benzylamine, naphthylamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0091] Examples of compounds having at least one hydroxyl group include alcohol compounds and phenolic compounds.

[0092] The alcohol compounds are not limited to the following, but include, for example, methyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, dothyl alcohol, stearyl alcohol, eicosyl alcohol, allyl alcohol, clotyl alcohol, propargyl alcohol, cyclopentanol, cyclohexanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and di Examples include monoalcohols such as ethylene glycol monobutyl; polyhydric alcohols such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butanediol, 1,4-butanediol, hydrogenated bisphenol A, neopentyl glycol, glycerin, trimethylolpropane, and pentaerythritol; and polyhydric alcohols such as compounds having two or more secondary hydroxyl groups in one molecule, obtained by the reaction of a compound having at least one epoxy group with a compound having at least one hydroxyl group, carboxyl group, primary amino group, secondary amino group, or thiol group. These alcohol compounds may be primary, secondary, or tertiary alcohols.

[0093] Examples of phenolic compounds include, but are not limited to, monophenols such as carbolic acid, cresol, xylenol, carvacrol, motil, and naphthol, and polyhydric phenols such as catechol, resorcinol, hydroquinone, bisphenol A, bisphenol F, pyrogallol, phloroglucin, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0094] The reaction conditions for producing two or more reaction products selected from the group consisting of isocyanate compounds, active hydrogen compounds, epoxy resins, and amine compounds, which are contained in the shell constituting the capsule-type curing agent as described above, are not particularly limited, but are usually in the temperature range of -10°C to 150°C and for a reaction time of 10 minutes to 12 hours.

[0095] When using an isocyanate compound and an active hydrogen compound, the mixing ratio is preferably in the range of 1:0.1 to 1:1000, expressed as (isocyanate group in the isocyanate compound): (active hydrogen in the active hydrogen compound) (equivalent ratio).

[0096] The reaction may be carried out in a predetermined dispersion medium as needed. Examples of dispersion media include solvents, plasticizers, and resins. Examples of solvents, but not limited to the following, include hydrocarbons such as benzene, toluene, xylene, mesitylene, cyclohexane, mineral spirits, and naphtha; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); esters such as ethyl acetate, n-butyl acetate, and propylene glycol monomethyl ethyl ether acetate; alcohols such as methanol, isopropanol, n-butanol, butyl cellosolve, and butyl carbitol; and water. Examples of plasticizers, but not limited to the following, include phthalate diester plasticizers such as dibutyl phthalate and di(2-ethylhexyl) phthalate; aliphatic dibasic acid ester plasticizers such as di(2-ethylhexyl) adipate; phosphate triester plasticizers such as tricresyl phosphate; and glycol ester plasticizers such as polyethylene glycol ester. Examples of resins include, but are not limited to, silicone resins, epoxy resins, and phenolic resins.

[0097] The proportion of the reaction product described above in the shell (S) is usually 1% by mass or more, preferably 50% by mass or more, and may also be 100% by mass.

[0098] In a encapsulated curing agent, the following methods (1) to (3) can be used to form a shell (S) that covers the surface of the core (C): (1) A method in which the shell components and curing agent particles are dissolved and dispersed in a solvent which is a dispersion medium, and then the solubility of the shell components in the dispersion medium is reduced to precipitate the shell on the surface of the curing agent particles for epoxy resin. (2) A method in which curing agent particles are dispersed in a dispersion medium, and the material that forms the shell is added to this dispersion medium to precipitate it on the curing agent particles for epoxy resin. (3) A method in which the raw material components that form the shell are added to the dispersion medium, and the surface of the curing agent particles is used as a reaction site to generate the shell-forming material.

[0099] Of the methods described above, methods (2) and (3) are particularly preferred because they allow the reaction and coating to be carried out simultaneously.

[0100] Examples of dispersion media include solvents, plasticizers, and resins. Furthermore, as solvents, plasticizers, and resins, the examples listed above for use when obtaining reaction products of any two or more of the isocyanate compounds, active hydrogen compounds, curing agents for epoxy resins, epoxy resins, and amine compounds can be used.

[0101] The method for separating the microencapsulated curing agent from the dispersion medium after forming the shells by the methods described in (2) and (3) above is not particularly limited, but it is preferable to separate and remove the unreacted raw materials together with the dispersion medium after the shells have been formed. One such method is to remove the dispersion medium and the unreacted shell-forming material by filtration.

[0102] It is preferable to wash the encapsulated curing agent after removing the dispersion medium. Washing the encapsulated curing agent removes any unreacted shell-forming material adhering to its surface.

[0103] The washing method is not particularly limited, but the residue after filtration can be washed using a dispersion medium or a solvent that does not dissolve the encapsulated curing agent. After filtration and washing, the encapsulated curing agent can be dried to obtain it in powder form. The drying method is not particularly limited, but it is preferable to dry it at a temperature below the melting point or softening point of the curing agent. By making the encapsulated curing agent into a powder, the compounding process with epoxy resin (A) can be easily applied.

[0104] The temperature during drying of the capsule-type curing agent is not particularly limited, but is preferably 10 to 40°C, more preferably 15 to 35°C, and more preferably 20 to 30°C.

[0105] The humidity during drying of the capsule-type curing agent is not particularly limited, but is preferably 10 to 60% RH, more preferably 30 to 55% RH, and more preferably 40 to 55% RH. By keeping the humidity during drying within the above range, the disappearance of isocyanate groups due to the reaction of water in the air with isocyanate groups in the curing agent (B) can be suppressed, and the amount of isocyanate groups can be adjusted to an appropriate amount.

[0106] The drying time for the capsule-type curing agent is not particularly limited, but is preferably 1 to 10 hours, more preferably 2 to 9 hours, and more preferably 3 to 8 hours.

[0107] The shell (S) formation reaction is usually carried out at a temperature range of -10°C to 150°C, preferably 0°C to 100°C, with a reaction time of 10 minutes to 72 hours, preferably 30 minutes to 24 hours.

[0108] Furthermore, the thickness of the shell constituting the microencapsulated curing agent is preferably 5 nm to 1000 nm, and more preferably 10 nm to 100 nm. By making the shell thickness 5 nm or more, the storage stability of the epoxy resin composition can be further improved. Also, by making the shell thickness 1000 nm or less, the curability can be further improved. The thickness referred to here is the average layer thickness, which can be confirmed by the staining treatment and TEM observation described above.

[0109] The content of the curing agent (B) is not particularly limited, but is preferably 20 to 65% by mass, more preferably 20 to 60% by mass, and even more preferably 25 to 55% by mass, relative to the total amount of the epoxy resin composition. When the content of the curing agent (B) is within the above range, the curability of the epoxy resin composition is improved and tends to have excellent adhesion.

[0110] The content of the curing agent (B) is not particularly limited, but is preferably 20 to 60% by mass, more preferably 20 to 50% by mass, and even more preferably 25 to 40% by mass, relative to the total amount of epoxy resin (A) and the curing agent (B). When the content of the curing agent (B) is within the above range, the curability of the epoxy resin composition is improved and tends to have excellent adhesion.

[0111] (Compound represented by formula (1)) The epoxy resin composition of this embodiment may further contain the compound represented by the following formula (1). Including the compound represented by the following formula (1) tends to result in superior curing abruptness.

[0112]

[0113] In the above formula (1), R １ ~R ９ Each of these independently represents a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a heteroatom, or a substituent containing a halogen atom. ５ ~R ９ Any of the selected compounds may be fused ring compounds in which any of them are present in the same ring.

[0114] In the above formula (1), R １ The substituent is preferably a heteroatom, and more preferably a hydroxyl group.

[0115] In the above formula (1), R ２ , R ３ and R ４ Preferably, it is a hydrogen atom.

[0116] In the above formula (1), R ５ ~R ９ Each of these is independently preferably a hydrogen atom or an alkyl group, and more preferably R ５ ~R８ is a hydrogen atom, and R ９ It is an alkyl group, and it is a methyl group.

[0117] The compound represented by formula (1) above is not limited to the following, but examples include 3-phenoxy-1-propanol, 3-phenoxy-1,2-propanediol, 3-phenoxy-1,3-propanediol, 3-(ortho-toluoxy)-1,2-propanediol, 3-(2-methoxyphenoxy)propane-1,2-diol, bisphenol A (3-hydroxypropyl) glycidyl ether, and bisphenol A (2,3-dihydroxypropyl) glycidyl ether, among which 3-(ortho-toluoxy)-1,2-propanediol is preferred.

[0118] From the viewpoint of superior curing abruptness, the content of the compound represented by formula (1) above is preferably 0.0001 to 0.1% by mass, more preferably 0.001 to 0.01% by mass, and preferably 0.004 to 0.008% by mass, relative to the total amount of the epoxy resin composition.

[0119] (Other Additives) The epoxy resin composition of this embodiment may, if necessary, further contain other additives in addition to the components described above, such as fillers, pigments, dyes, flow regulators, thickeners, mold release agents, wetting agents, flame retardants, and surfactants. These additives may be used individually or in combination of two or more.

[0120] Examples of fillers include organic fillers and inorganic fillers. Examples of organic fillers, though not limited to the following, include acrylic resins, silicone resins, butadiene rubber, polyesters, polyurethanes, polyvinyl butyral, polyarylate, polymethyl methacrylate, acrylic rubber, polystyrene, NBR, SBR, silicone-modified resins, and organic fine particles of copolymers containing these as components. Inorganic fillers include, but are not limited to, silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium dioxide, aluminum oxide (alumina), fused silica (fused spherical silica, fused crushed silica), synthetic silica, and crystalline silica; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates such as barium sulfate and calcium sulfate; sulfites such as calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, and silicon nitride; conductive particles such as gold, silver, nickel, copper, palladium, platinum, bismuth, tin, and their alloys (especially bismuth-tin alloys, solder, etc.), aluminum, indium tin oxide, silver-plated copper, silver-plated aluminum, metal-plated glass spheres, silver-plated fibers, silver-plated resin antimond-doped tin, tin oxide, carbon fiber, graphite, and carbon black.

[0121] Examples of pigments, though not limited to the following, include kaolin, chalk powder, gypsum, antimony trioxide, pentone, aerosol, lithopone, and barite.

[0122] Examples of dyes include, but are not limited to, natural dyes such as plant-derived dyes like madder and indigo, mineral-derived dyes like yellow ochre and red ochre, synthetic dyes such as alizarin and indigo, and fluorescent dyes.

[0123] Examples of flow regulators include, but are not limited to, silane coupling agents, organic silane compounds such as silicone oils and silicone gels; organic titanium compounds such as titanium tetraisopropoxide and titanium diisopropoxybis(acetylacetonate); and organic zirconium compounds such as zirconium tetran-butoxide and zirconium tetraacetylacetonate.

[0124] Examples of thickening agents include, but are not limited to, animal-derived thickeners such as gelatin; plant-derived thickeners such as polysaccharides and cellulose; and chemically synthesized thickeners such as polyacrylic thickeners, modified polyacrylic thickeners, polyether thickeners, urethane-modified polyether thickeners, and carboxymethylcellulose.

[0125] Examples of release agents include, but are not limited to, fluorine-based release agents, silicone-based release agents, and acrylic-based release agents consisting of copolymers of glycidyl (meth)acrylate and linear alkyl (meth)acrylate esters having 16 to 22 carbon atoms.

[0126] Examples of wetting agents include, but are not limited to, unsaturated polyester copolymer wetting agents having acidic groups, such as acrylic polyphosphate esters.

[0127] Examples of flame retardants include, but are not limited to, halogenated flame retardants such as chlorine compounds and bromine compounds, phosphorus-based flame retardants such as condensed phosphate esters, and antimony-based flame retardants such as antimony trioxide and antimony pentoxide.

[0128] Examples of surfactants include, but are not limited to, anionic surfactants such as alkylbenzene sulfonates and alkyl polyoxyethylene sulfates, cationic surfactants such as alkyldimethylammonium salts, amphoteric surfactants such as alkyldimethylamine oxide and alkyl carboxybetaine, and nonionic surfactants such as linear alcohols with 25 or more carbon atoms and fatty acid esters.

[0129] The other additives mentioned above can be used individually or in combination of two or more types, depending on the desired properties of the epoxy resin composition of this embodiment, and their amounts can also be appropriately selected.

[0130] [Method for Manufacturing Epoxy Resin Composition] The epoxy resin composition of this embodiment can be manufactured by mixing and kneading the above-mentioned components. The mixing and kneading method is not particularly limited, but examples include using a reactor with stirring blades, a planetary mixer, a kneader, a roll, a homodisper, an extruder, etc. The mixing and kneading process may be carried out in a cooled state, at room temperature, or under heating. The kneading temperature varies depending on the viscosity and melting temperature of the epoxy resin, but is usually 5 to 250°C, preferably 10 to 150°C, and more preferably 15 to 120°C. If the kneading temperature is too high, exceeding 250°C, the curing reaction will proceed during kneading, and the viscosity will tend to increase. Also, if the kneading temperature is too low, below 5°C, the viscosity of the epoxy resin or curing agent will increase, making it difficult to knead, or moisture in the air will adhere to the epoxy resin composition, and that moisture will vaporize during curing, causing voids to be generated in the cured product.

[0131] [Specific Embodiments of the Epoxy Resin Composition] The epoxy resin composition of this embodiment can be used in a variety of forms, such as paste or film, for a wide range of applications. For example, it is useful as a encapsulant, conductive material, thermally conductive material, insulating material, adhesive for camera modules, structural adhesive, matrix resin for fiber-reinforced plastics, impregnation adhesive, interlayer insulating film, film-type solder resist, encapsulation sheet, conductive film, anisotropic conductive film, and thermally conductive film. In other words, the encapsulant, conductive material, thermally conductive material, insulating material, adhesive for camera modules, structural adhesive, matrix resin for fiber-reinforced plastics, impregnation adhesive, interlayer insulating film, film-type solder resist, encapsulation sheet, conductive film, anisotropic conductive film, and thermally conductive film of this embodiment all include the epoxy resin composition of this embodiment. Furthermore, a preferred embodiment of the composition of this embodiment is that it is also useful as a curing agent composition that can cure resins, etc., by heating, and is particularly useful as a curing agent composition for epoxy resins. For example, it is particularly useful as a structural adhesive because it exhibits excellent storage stability in a 50°C environment and can suppress a decrease in peel strength.

[0132] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited in any way by these examples and comparative examples.

[0133] The methods for measuring and evaluating each physical property are described below.

[0134] [Method for measuring and evaluating the physical properties of epoxy resin compositions] (Infrared absorption spectrum) The epoxy resin compositions prepared in the examples and comparative examples described later were applied to a 1 cm thick rock salt plate and used as measurement samples. Measurements were performed using a JASCO FT / IR-6600 under the following conditions.

[0135] (Measurement conditions) Measurement range: 4000-700 cm －１ Total number of attempts: 16 Disassembly: 4 cm －１ H ２ Subtraction: ON CO ２ Subtraction: ON

[0136] The obtained measurement results were plotted on a graph with wavenumber on the x-axis and absorption on the y-axis. The absorption peak heights of P1 and P2 were determined using the following method, and the value of P2 / P1 was calculated. In Table 1, if P1 and / or P2 were not detected, it was indicated as N / D. P1: wavenumber 942–957 cm －１ The coordinates of the minimum point in the range (X １ , Y １ ), 876-897cm －１ The coordinates of the minimum point in the range (X ２ , Y ２ ), 880-950cm －１ The coordinates of the maximum point are (X ｍ , Y ｍ When Y is set to ), ｍ And the x-coordinate is X on the line connecting the two minimum points. ｍ P1 was defined as the difference in the Y-coordinate values ​​of the points where this condition was met. That is, it is expressed by the following equation (1).

[0137]

[0138] P2: Wave number 2310-2347cm －１ The coordinates of the minimum point in the range (X １ , Y １ ), 2167-2230cm －１ The coordinates of the minimum point in the range (X ２ , Y ２ ), 2200-2350cm －１ The coordinates of the maximum point are (X ｍ , Y ｍ When Y is set to ), ｍ And the x-coordinate is X on the line connecting the two minimum points. ｍ P2 was defined as the difference in the Y-coordinate values ​​of the points where this condition is met. That is, it is expressed by the following equation (2).

[0139]

[0140] (Evaluation of Bubble Generation Suppression) The suppression of bubble generation in the epoxy resin composition was evaluated by the number of bubbles generated using the following method. The epoxy resin compositions prepared in the examples and comparative examples described later were applied to an aluminum sheet using a four-sided film applicator (coating width 60 mm, gap 500 μm) manufactured by Allgood Co., Ltd., and stored for 168 hours at 35°C and 80% RH. After that, the surface of the epoxy resin composition was observed with a microscope (VH-Z500R, manufactured by KEYENCE Co., Ltd.), and the number of bubbles with a diameter of 2 μm or more generated in a 156 × 117 μm area at an arbitrary observation position was counted. The average value of the number of bubbles at five arbitrary observation positions was calculated, and the suppression of bubble generation was evaluated according to the following criteria. <Evaluation Criteria> ◎ 1 or less ○ 2 to 4 △ 5 to 20 × 21 or more

[0141] (Evaluation of Adhesion) The adhesion of the epoxy resin compositions was evaluated by measuring the adhesive strength using the following method. A 1 mm thick silicone rubber with a 2 mm diameter hole was placed on a silicon substrate that had been cleaned with HF (fluorine). The epoxy resin compositions prepared in the examples and comparative examples described later were poured into the hole and cured in a hot air circulating oven heated to 150°C for 1 hour. After that, the silicone rubber was removed and the adhesive strength was measured using a shear bonder (4000 Plus Bondtester, Nordson). The adhesion was evaluated according to the following criteria: <Evaluation Criteria> ◎ 10 MPa or more 〇 8 MPa or more and less than 10 MPa △ 5 MPa or more and less than 8 MPa × Less than 5 MPa

[0142] (Evaluation of Curing Steepness) Using a DSC7020 (manufactured by Hitachi High-Tech Science Co., Ltd.), 10 mg of the epoxy resin compositions prepared in the examples and comparative examples described below was weighed and heated from 25°C to 250°C at a heating rate of 10°C / min. The DSC curve and the DDSC curve, which is the first derivative of DSC, were obtained. The DDSC value is set to be negative when the heat generation of the sample increases and positive when the heat generation decreases. The maximum temperature at which the DDSC value becomes -0.2 mW / min at temperatures below the temperature at which the DDSC value is minimum was defined as the heat generation start temperature, and the maximum temperature at which the DDSC value becomes 0.2 mW / min was defined as the heat generation end temperature. The curing steepness was evaluated according to the following criteria: <Evaluation Criteria> ◎ Below 55°C 〇 55°C or more and less than 70°C △ 70°C or more and less than 80°C × 80°C or more and less than 90°C ×× 90°C or more

[0143] (Measurement by liquid chromatography) One g of the composition prepared in the examples and comparative examples described later was uniformly mixed with three g of toluene. The mixture was then centrifuged, and the toluene layer containing the dissolved epoxy resin (A) was recovered. The obtained toluene layer was diluted with acetonitrile, and this was used as the LC (liquid chromatography) measurement solution. The detailed conditions for the LC measurement were as follows. LC: Instrument: Ultra-high performance liquid chromatography (UPLC H-Class (plus), Waters), MS ionization auxiliary solution: 5 mM sodium acetate / methanol solution, MS ionization mode: positive, MS ionization voltage: 15 V (resin), 25 V (adduct), Column: HSS-C18, Column temperature: 40°C, Sample concentration: 100 ppm (LC-MS), 0.5 wt% (LC-PDA only), Injection volume: 1 μL, Flow rate: 0.2 mL / min, Sample dilution solvent: Acetonitrile, Detection: Absorbance detector (PDA, 200-400 nm), Flow rate: 0.3 mL / min, Mobile phase: A = water, B = acetonitrile, C = methanol, D = 0.1% by mass of formic acid

[0144] Gradient: 0 minutes = A: 56%, B: 30%, C: 14% 30 minutes = B: 100%

[0145] Retention time: Compound represented by formula (2): Retention time of compound represented by formulas (6) and (7) Compound represented by formula (3): 9.1 min Compound represented by formula (4): 22.5 min Compound represented by formula (5): 26.2 min Compound represented by formula (6): 15.0 min Compound represented by formula (7): 16.3 min

[0146] From the peak areas obtained by the LC measurements described above, the area of ​​the peak attributed to the compound represented by equation (2) was set to 100, and the ratio of the peak areas attributed to each compound was calculated. The results are shown in Table 2.

[0147] (Measurement of viscosity at 25°C) The viscosity of the compositions prepared in the examples and comparative examples described later was measured at 25°C using an E-type viscometer (TVE-35H, manufactured by Toki Sangyo Co., Ltd.).

[0148] (Evaluation of storage stability at 50°C) The compositions prepared in the examples and comparative examples described later were stored in an oven set to 50°C for 3 days, and the viscosity of the compositions after storage was measured using an E-type viscometer (TVE-35H, manufactured by Toki Sangyo Co., Ltd.). The ratio of the viscosity after storage to the viscosity at 25°C (thickening ratio) was calculated using the following formula, and the storage stability at 50°C was evaluated according to the following criteria. Thickening ratio = viscosity after storage / viscosity at 25°C <Evaluation criteria> ○ Less than 1.5 × 1.5 or more

[0149] (Oil surface T-shaped peel strength) A 0.5 mm thick cold-rolled steel sheet (manufactured by Nippon Test Panel Co., Ltd.) that has been bent into an L-shape at 90° to create a bonding area of ​​25 x 150 mm was subjected to 4.5 g / m² of industrial lubricant (Fuchs, Renep CGLP68). 2The material was coated in this manner, left for one day at 25°C, and then the compositions prepared in the examples and comparative examples described later were applied. Next, glass beads with a particle size of 100 μm were sprinkled on to adjust the thickness, and then another steel plate coated with industrial lubricant in the same manner as above was bonded on top. After that, the composition was cured by heating in an oven preheated to 150°C for one hour to obtain a test piece for oil surface T-shaped peel strength. Using the obtained test piece, the oil surface T-shaped peel strength was measured in a constant temperature and humidity chamber at 23°C and 50% RH using an Autograph (Shimadzu, AGS-X) with a unit movement speed of 100 mm / min. The oil surface T-shaped peel strength was evaluated by obtaining the value at which the strength became constant in the graph obtained from the measurement, calculating the median value obtained from n=5 measurements, and evaluating it according to the following criteria. <Evaluation Criteria> ○ 5N / 25mm or more × Less than 5N / 25mm

[0150] [Preparation of Epoxy Resin (A)] (Preparation Example 1: Preparation of Epoxy Resin A) 20 parts of bisphenol A and 160 parts of epichlorohydrin, in the ratio of formula (10):(11) below = 96:4 (LC area ratio), were added to a flask. The temperature was adjusted to 55°C while stirring, and then 14.5 parts of 48.5% by mass sodium hydroxide were added over 2 hours. The mixture was reacted at 100°C for 6 hours. After the reaction was complete, the unreacted epichlorohydrin was removed from the reactant under reduced pressure by distillation, then dissolved in toluene, and the sodium chloride was removed by filtration. After washing with water, the toluene was removed under reduced pressure to obtain epoxy resin Pre-A (epoxy equivalent: 178 g / eq). Next, epoxy resin Pre-A was subjected to thin-film distillation to obtain epoxy resin A (epoxy equivalent: 169 g / eq). After separating the obtained epoxy resin A by LC, mass spectrometry (MS) and NMR were performed, confirming that it contained the compounds represented by formulas (6) and (7) above.

[0151] (Preparation Example 2: Preparation of Epoxy Resin B) 20 parts of bisphenol A and 60 parts of epichlorohydrin, with formula (10):(11) = 96:4 (LC area ratio), were added to a flask and stirred while the temperature was adjusted to 55°C. Then, 14.5 parts of 48.5% by mass sodium hydroxide were added over 2 hours, and the mixture was reacted at 110°C for 4 hours. After the reaction was complete, the unreacted epichlorohydrin was removed from the reactant under reduced pressure by distillation, then dissolved in toluene, and the sodium chloride was removed by filtration. After washing with water, the toluene was removed under reduced pressure to obtain epoxy resin B (epoxy equivalent; 201 g / eq). The obtained epoxy resin B was measured by LC-MS, and, taking into account the results for epoxy resin A, it was confirmed that it contained compounds represented by formulas (3), (4), (5), (6), and (7).

[0152] [Preparation of curing agent (B)] (Preparation example 3: curing agent B-1) <Preparation process for block-shaped curing agent> 170 parts by weight of bisphenol A diglycidyl ether, 82 parts by weight of 2-methylimidazole, and 0.5 parts by weight of the compound represented by the following formula (12) were reacted at 80°C in a 1:1 mixed solvent of n-butanol and toluene.

[0153]

[0154] Subsequently, the pressure was reduced to 10 mmHg and heated at 150°C for 3 hours to remove excess amine along with the solvent, yielding a solid block-shaped curing agent 1 at 25°C. Analysis by LC (liquid chromatography) revealed that the obtained curing agent contained 8 area percent of the compound represented by the following formula (8).

[0155]

[0156] <Grinding Process> The obtained block-shaped hardening agent 1 was ground using a jet mill to obtain hardening agent particles 1 with an average particle size D50 under sieving of the solid at 25°C of 2.2 μm.

[0157] <Microencapsulation Process> 10 g of curing agent particle 1 and 4 g of tolylene diisocyanate (Cosmonate T-80, manufactured by Mitsui Chemicals) as a encapsulation membrane agent were dispersed in 200 g of cyclohexane. After stirring at 60°C for 5 hours, the mixture was dispensed onto filter paper and washed three times with toluene to remove any remaining tolylene diisocyanate. Finally, the solvent was removed by drying at 25°C and 50% RH for 5 hours to obtain curing agent B-1.

[0158] (Preparation Example 4: Curing Agent B-2) Curing agent B-2 was obtained in the same manner as in Preparation Example 3, except that the drying conditions for the microencapsulation step in Preparation Example 3 were changed to drying at 25°C and 50% RH for 3 hours.

[0159] (Preparation Example 5: Curing Agent B-3) Curing agent B-3 was obtained in the same manner as in Preparation Example 3, except that the drying conditions for the microencapsulation step in Preparation Example 3 were changed to drying at 25°C and 40% RH for 4 hours.

[0160] (Preparation Example 6: Curing Agent B-4) Curing agent B-4 was obtained in the same manner as in Preparation Example 3, except that the drying conditions for the microencapsulation step in Preparation Example 3 were changed to drying at 25°C and 40% RH for 8 hours.

[0161] (Preparation Example 7: Curing Agent B-5) A block-shaped curing agent 2 was obtained in the same manner as in Preparation Example 3, except that the compound represented by formula (2) above was not added in the preparation step of the block-shaped curing agent in Preparation Example 3. Then, curing agent B-5 was obtained in the same manner as in Preparation Example 3, except that the drying conditions in the microencapsulation step of Preparation Example 3 were changed to drying under conditions of 25°C and 50% RH for 48 hours.

[0162] (Preparation Example 6: Curing Agent B-6) A block-shaped curing agent 2 was obtained in the same manner as in Preparation Example 1, except that the compound represented by formula (2) above was not added in the preparation step of the block-shaped curing agent in Preparation Example 1. Then, in the microencapsulation step of Preparation Example 3, curing agent B-6 was obtained in the same manner as in Preparation Example 3, except that after being dispensed onto filter paper, washing with toluene was not performed, and it was dried at 25°C at a pressure of 10 mmHg or less for 24 hours.

[0163] (Curing agent B-7) Block-shaped curing agent 2 was obtained in the same manner as in Preparation Example 3, except that the compound represented by formula (2) above was not added in the preparation step of the block-shaped curing agent in Preparation Example 3. Then, the block-shaped curing agent 2 was pulverized in the same manner as in the pulverization step of Preparation Example 3, and 50 parts by mass each of the obtained curing agent particles 2, jER(registered trademark)-828 (bisphenol A type epoxy resin, epoxy equivalent 186 g / eq), and jER(registered trademark)-806 (bisphenol F type epoxy resin, epoxy equivalent 170 g / eq) were weighed out and kneaded using a foam remover (manufactured by Shinki Co., Ltd.) to obtain composition 1. Referring to the method described in Example 1 of Japanese Patent Application Publication No. 2009-132931, 5 parts by weight of tolylene diisocyanate (Cosmonate T-80, manufactured by Mitsui Chemicals, Inc.) was added to composition 1, and the reaction was carried out at 40°C with a stirring bar for 2 hours. Subsequently, the mixture was stored at 35°C for 48 hours to obtain microencapsulated curing agent B-8 containing epoxy resin. The reaction rate of tolylene diisocyanate was over 99%, and tolylene diisocyanate was not detected by LC (liquid chromatography).

[0164] [Examples 1-9, Comparative Examples 1-4] Each component listed in Tables 1 and 2 was weighed in the amounts listed in Tables 1 and 2, and mixed using a foam remover (manufactured by Shinky Co., Ltd.) to obtain the epoxy resin compositions of each example. Epoxy resins A-8 and A-9 and curing agents B-1 to B-7 are the epoxy resins and curing agents prepared in the above preparation examples, and the other components listed in Tables 1 and 2 are as follows. Note that the components of epoxy compound (A) were heated in an oven at a set temperature of 70°C for 2 hours, then stirred for 2 minutes and degassed for 3 minutes using a foam remover, and weighed after cooling to room temperature.

[0165] (Epoxy resin (A)) A-1: ​​jER(registered trademark)-828 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin) A-2: jER(registered trademark)-YL980 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin) A-3: jER(registered trademark)-YL983U (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin) A-4: jER(registered trademark)-806 (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin) A-5: AER250 (manufactured by Asahi Kasei Corporation, bisphenol A type epoxy resin) A-6: jER(registered trademark)-834 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin) A-7: Bisphenol A (2,3-dihydroxypropyl) glycidyl ether (manufactured by Sigmar-Aldrich) A-8: Preparation example 1: Epoxy resin A A-9: Preparation example 2: Epoxy resin B

[0166] Compound 1: 3-(o-tolyloxy)-1,2-propanediol (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0167] Table 1 shows the physical properties and evaluation results of each example epoxy resin composition obtained.

[0168]

[0169] As shown in Table 1, the epoxy resin (A) and curing agent (B) of Examples 1 to 7 are included, and when measured by infrared spectroscopy, the infrared absorption spectrum is 880 to 950 cm⁻¹. －１ The maximum peak intensity (P1) in the range of 2200–2350 cm －１ Epoxy resin compositions with a ratio (P2 / P1) of 0.005 to 0.2 of the maximum peak intensity (P2) within the specified range can achieve both suppression of bubble generation and good adhesion. On the other hand, comparative examples 1 to 4, whose ratio (P2 / P1) is outside the above range, show inferior suppression of bubble generation or poor adhesion.

[0170] Furthermore, it can be seen that the epoxy resin compositions containing the compound represented by formula (1) in Examples 5 and 6 also exhibit excellent curing abruptness.

[0171] Furthermore, as shown in Table 2, the compositions of Examples 1, 7 to 9, which contain epoxy resin (A) and a curing agent (B), and in which epoxy resin (A) contains the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5), and in which the area of ​​the peaks attributed to the compounds represented by formulas (2) to (5) is within a specific range when the composition is measured by liquid chromatography, exhibit excellent storage stability and improved peel strength in an environment of 50°C.

[0172] The epoxy resin composition of this embodiment has industrial applicability in applications such as encapsulants, conductive materials, thermally conductive materials, insulating materials, adhesives for camera modules, structural adhesives, matrix resins for fiber-reinforced plastics, impregnation adhesives, interlayer insulating films, film-type solder resists, encapsulating sheets, conductive films, anisotropic conductive films, and thermally conductive films.

Claims

1. An epoxy resin composition comprising an epoxy resin (A) and a curing agent (B), wherein the infrared absorption spectrum of the epoxy resin composition measured by infrared spectroscopy is 880 to 950 cm⁻¹. －１ The maximum peak intensity (P1) in the range of 2200–2350 cm －１ An epoxy resin composition in which the ratio (P2 / P1) of the maximum peak intensity (P2) within a given range is 0.005 or more and 0.2 or less.

2. The epoxy resin composition according to claim 1, further comprising a compound represented by the following formula (1). (In formula (1), R １ ~R ９ Each of these independently represents a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a heteroatom, or a substituent containing a halogen atom. ５ ~R ９ (Any of the selected compounds may be fused ring compounds in which any of them are present in the same ring.) 3. R ​​in formula (1) above １ The epoxy resin composition according to claim 2, wherein the group is a hydroxyl group.

4. The R in said formula (1) ２ , R ３ and R ４ are hydrogen atoms, the epoxy resin composition according to claim 2.

5. The epoxy resin composition according to claim 1, wherein the epoxy resin (A) comprises a compound represented by the following formula (2), a compound represented by the following formula (3), a compound represented by the following formula (4), and a compound represented by the following formula (5), and when the composition is measured by liquid chromatography, the area of ​​the peak attributed to the compound represented by formula (2) is set to 100, the area of ​​the peak attributed to the compound represented by formula (3) is 0.4 to 3.5, the area of ​​the peak attributed to the compound represented by formula (4) is 4 to 12, and the area of ​​the peak attributed to the compound represented by formula (5) is 2 to 8.

6. The epoxy resin composition according to claim 5, wherein the epoxy resin (A) comprises a compound represented by the following formula (2), a compound represented by the following formula (3), a compound represented by the following formula (4), and a compound represented by the following formula (5), and when the composition is measured by liquid chromatography, the area of ​​the peak attributed to the compound represented by formula (2) is set to 100, the area of ​​the peak attributed to the compound represented by formula (3) is 0.4 to 3.5, the area of ​​the peak attributed to the compound represented by formula (4) is 5 to 11, and the area of ​​the peak attributed to the compound represented by formula (5) is 2 to 8.

7. The composition according to claim 1, wherein the epoxy resin (A) comprises a compound represented by the following formula (6) and a compound represented by the following formula (7), and when the composition is measured by liquid chromatography, the ratio of the area of ​​the peak attributed to the compound represented by the following formula (6) to the area of ​​the peak attributed to the compound represented by the following formula (7) is 95 to 99:1 to 5, with the sum being 100.

8. The epoxy resin composition according to claim 1, wherein the curing agent (B) contains an amine compound.

9. The epoxy resin composition according to claim 1, wherein the curing agent (B) comprises an imidazole compound.

10. The epoxy resin composition according to claim 1, wherein the curing agent (B) comprises a compound represented by the following formula (8).

11. The composition according to claim 1, wherein the curing agent (B) comprises at least one selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, and the compound of formula (8), the compound represented by formula (2) comprises the compound represented by the following formula (6) and the compound represented by the following formula (7), and when the composition is measured by liquid chromatography, the ratio of the peak area attributed to the compound represented by the following formula (6) to the peak area attributed to the compound represented by the following formula (7) is 95 to 99:1 to 5, with the sum being 100.

12. The epoxy resin composition according to claim 1, wherein the epoxy resin (A) comprises the following formula (9) and a phenol novolac type epoxy resin, and when the composition is measured by liquid chromatography, the area of ​​the peak attributed to the following formula (9) is set to 100, and the area of ​​the peak attributed to the phenol novolac type epoxy resin is set to 0.01 to 10.

13. The epoxy resin composition according to claim 1, wherein the curing agent (B) comprises a capsule-type curing agent.

14. The epoxy resin composition according to claim 1, wherein the content of the curing agent (B) is 20 to 60% by mass relative to the total amount of the epoxy resin (A) and the curing agent (B).

15. A sealing material comprising the epoxy resin composition according to any one of claims 1 to 14.

16. A conductive material comprising the epoxy resin composition according to any one of claims 1 to 14.

17. A thermally conductive material comprising the epoxy resin composition according to any one of claims 1 to 14.

18. An insulating material comprising the epoxy resin composition according to any one of claims 1 to 14.

19. An adhesive for a camera module comprising the epoxy resin composition according to any one of claims 1 to 14.

20. A structural adhesive comprising the epoxy resin composition according to any one of claims 1 to 14.

21. A matrix resin for fiber-reinforced plastics comprising the epoxy resin composition according to any one of claims 1 to 14.

22. An impregnation adhesive comprising the epoxy resin composition according to any one of claims 1 to 14.

23. An interlayer insulating film comprising the epoxy resin composition according to any one of claims 1 to 14.

24. A film-type solder resist comprising the epoxy resin composition according to any one of claims 1 to 14.

25. A sealing sheet comprising the epoxy resin composition according to any one of claims 1 to 14.

26. A conductive film comprising the epoxy resin composition according to any one of claims 1 to 14.

27. An anisotropic conductive film comprising the epoxy resin composition according to any one of claims 1 to 14.

28. A thermally conductive film comprising the epoxy resin composition according to any one of claims 1 to 14.

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