Epoxy resin composition

Abstract

An object of the present invention is to provide an epoxy resin composition having a low viscosity and giving a cured product which has a low elasticity and in which a decrease in tensile elastic modulus and adhesive force is suppressed even when stored at a high temperature.SOLUTION: The epoxy resin composition comprises (A) an epoxy resin other than the following component (B), (B) a polyoxyalkylene-containing epoxy resin having two epoxy groups in one molecule, (C) a phenol resin which is liquid at 25 °C and has one or more functional groups containing an unsaturated double bond in one molecule, and (D) an antioxidant.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an epoxy resin composition, and more particularly to an epoxy resin composition containing a liquid phenolic resin. [Background technology]

[0002] Epoxy resin compositions have excellent adhesive strength, heat resistance, and electrical properties, and are therefore used as sealants and adhesives in the fields of electrical and electronic equipment parts, automotive parts, and the like.

[0003] Epoxy resin compositions generally use a curing agent that reacts with epoxy groups, and examples of the curing agent include amine-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, thiol-based curing agents, etc. Among them, phenol-based curing agents are also used in fields such as power semiconductors due to their excellent heat resistance reliability and moisture resistance reliability (Patent Document 1).

[0004] By introducing allyl or alkyl groups into solid phenolic curing agents, they can be used as liquid phenolic resins. Because cured products of epoxy resins and liquid phenolic resins have excellent moisture resistance, they are used in electronic materials such as underfills and adhesives (Patent Documents 2 and 3).

[0005] In recent years, with the miniaturization of electronic components, there has been a demand for epoxy resins with a lower elastic modulus in order to alleviate stress on the electronic components. The addition of high molecular weight thermoplastic resins has been investigated to improve impact resistance (Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-063145 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-241877 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-037529 [Patent Document 4] Japanese Patent Publication No. 2023-121887 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the addition of a high molecular weight thermoplastic resin increases viscosity, which reduces workability, and this problem remains unresolved. Therefore, an object of the present invention is to provide an epoxy resin composition that has low viscosity and gives a cured product with low elasticity, and that does not experience a decrease in tensile modulus or adhesive strength even when stored at high temperatures. [Means for solving the problem]

[0008]

[0003] As a result of extensive research aimed at solving the above problems, the present inventors have discovered that by blending a liquid phenolic resin having an unsaturated double bond such as an allyl group with a bifunctional epoxy resin having a polyoxyalkylene skeleton into an epoxy resin composition, a resin composition with low viscosity can be obtained, and the cured product thereof exhibits low elasticity. Furthermore, the present inventors have discovered that by incorporating an antioxidant into the epoxy resin composition together with the liquid phenolic resin, the decrease in tensile modulus and adhesive strength of the cured product when stored at high temperatures can be suppressed, leading to the completion of the present invention.

[0009] That is, the present invention provides the following epoxy resin composition. [1] (A) an epoxy resin other than the following component (B), (B) a polyoxyalkylene-containing epoxy resin having two epoxy groups in one molecule; (C) a phenolic resin that is liquid at 25°C and has one or more functional groups containing unsaturated double bonds in one molecule; and (D) Antioxidants An epoxy resin composition comprising:

[0010] The present invention further provides the following epoxy resin composition. [2] The epoxy resin composition according to the above [1], wherein the component (A) is an epoxy resin having one or more aromatic rings in one molecule. [3] The epoxy resin composition according to the above [1] or [2], wherein the component (A) is one or more selected from bisphenol A type epoxy resins, bisphenol F type epoxy resins, naphthalene type epoxy resins, and aminophenol type epoxy resins. [4] The epoxy resin composition according to any one of the above [1] to [3], wherein the component (B) has an epoxy equivalent of 170 g / eq. or more and 500 g / eq. or less. [5] The epoxy resin composition according to any one of the above [1] to [4], wherein the blending amount of the component (B) is 10 parts by mass or more and 500 parts by mass or less per 100 parts by mass of the epoxy resin (A). [6] The epoxy resin composition according to any one of the above [1] to [5], wherein in the component (C), the functional group containing an unsaturated double bond is an alkenyl group having 2 to 6 carbon atoms. [7] The component (C) is a compound represented by the following formula (1): [ka] (In the formula, R 1 are each independently a hydrogen atom or a group selected from a hydroxyl group, an alkenyl group having 2 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms; R 1 At least one of the groups is the alkenyl group, n is a number of 0 to 10, and X is a group of the following formula: [ka] (In the formula, R 2 are independently a hydrogen atom or a methyl group.) is a divalent linking group selected from the group consisting of.) The epoxy resin composition according to any one of the above [1] to [6], [8] The epoxy resin composition according to any one of the above [1] to [7], wherein the blending amount of the component (D) is 0.01 to 20 parts by mass per 100 parts by mass of the component (A). [9] The epoxy resin composition according to any one of the above items [1] to [8], wherein the molar equivalent ratio of phenolic hydroxyl groups contained in component (C) to the total molar equivalent of epoxy groups contained in components (A) and (B) is 0.1 to 2.0.

[10] The epoxy resin composition according to any one of the above [1] to [9], wherein the component (D) is at least one selected from the group consisting of phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

[11] The epoxy resin composition according to any one of the above [1] to

[10] , which has a viscosity at 25°C of 0.01 to 850 Pa·s.

[12] An adhesive comprising the epoxy resin composition according to any one of the above [1] to

[11] .

[13] An underfill agent comprising the epoxy resin composition according to any one of the above [1] to

[11] .

[14] A semiconductor device comprising a cured product of the epoxy resin composition according to any one of the above [1] to

[11] . [Effects of the Invention]

[0011] The epoxy resin composition of the present invention has low viscosity and provides a cured product with low elasticity. Furthermore, the epoxy resin composition of the present invention provides a cured product that can suppress a decrease in tensile modulus and adhesive strength even when stored at high temperatures. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below. The epoxy resin composition of the present invention comprises: (A) an epoxy resin other than the following component (B), (B) a polyoxyalkylene-containing epoxy resin having two epoxy groups in one molecule; (C) a phenolic resin that is liquid at 25°C and has one or more functional groups containing unsaturated double bonds in one molecule; and (D) Contains antioxidants.

[0013] [(A) Epoxy resin] Component (A) is an epoxy resin other than component (B) described below. This epoxy resin is the main component of the present invention. The epoxy resin is a low-molecular-weight prepolymer having two or more epoxy groups per molecule, preferably a prepolymer having a molecular weight of 300 to 8,000, more preferably a prepolymer having a molecular weight of 350 to 4,000, or a polymer formed by a ring-opening reaction of the epoxy groups of the prepolymer. The epoxy resin (A) in the present invention can be appropriately selected from known epoxy resins, as long as it is an epoxy resin other than component (B) described below.

[0014] Examples of the epoxy resin include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, and bisphenol F novolac-type epoxy resins; alicyclic epoxy resins such as dicyclopentadiene-type epoxy resins and 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate; polyfunctional phenol-type epoxy resins such as resorcinol-type epoxy resins and resorcinol novolac-type epoxy resins; aminophenol-type epoxy resins, stilbene-type epoxy resins, triazine-skeleton-containing epoxy resins, fluorene-skeleton-containing epoxy resins, triphenolalkane-type epoxy resins, biphenyl-type epoxy resins, xylylene-type epoxy resins, biphenylaralkyl-type epoxy resins, naphthalene-type epoxy resins; diglycidyl ether compounds of polycyclic aromatics such as anthracene; silicone-modified epoxy resins; and phosphorus-containing epoxy resins obtained by introducing a phosphorus compound into any of the above. These may be used alone or in combination of two or more.

[0015] Component (A) is preferably an epoxy resin that is liquid at room temperature (25°C). Generally, the epoxy resin has a viscosity at 25°C of 0.6 to 100 Pa·s, preferably 0.8 to 50 Pa·s. Component (A) preferably has an epoxy equivalent of 150 to 300, more preferably 160 to 280. From the viewpoint of heat resistance reliability and moisture resistance reliability, component (A) is preferably an epoxy resin having one or more aromatic rings per molecule. Particularly preferred epoxy resins are at least one selected from bisphenol A epoxy resins, bisphenol F epoxy resins, naphthalene epoxy resins, and aminophenol epoxy resins. As mentioned above, these may be used alone or in combination.

[0016] [(B) Polyoxyalkylene-containing epoxy resin having two epoxy groups per molecule] The component (B) of the present invention is an epoxy resin having two epoxy groups per molecule and a polyoxyalkylene skeleton. The epoxy resin is added for the purpose of reducing the elastic modulus of the cured product. The component (B) is a low-molecular-weight prepolymer having two epoxy groups per molecule, preferably a prepolymer with a molecular weight of 300 to 8,000, and more preferably a prepolymer with a molecular weight of 500 to 4,000.

[0017] Examples of polyoxyalkylene skeletons include polyethylene glycol skeletons and polypropylene glycol skeletons. Component (B) of the present invention may have the polyoxyalkylene skeleton in its molecule and can be selected from commonly known polyoxyalkylene-containing bifunctional epoxy resins. Examples include polyoxyethylene-type epoxy resins such as polyethylene glycol diglycidyl ether, and polyoxypropylene-type epoxy resins such as polypropylene glycol diglycidyl ether.

[0018] These may be used alone or in combination of two or more. The polyoxyalkylene-containing bifunctional epoxy resin is preferably liquid at room temperature (25°C). The viscosity of the polyoxyalkylene-containing bifunctional epoxy resin at 25°C is preferably 0.01 Pa·s to 100 Pa·s, more preferably 0.05 Pa·s to 75 Pa·s, and even more preferably 0.1 Pa·s to 50 Pa·s.

[0019] The polyoxyalkylene-containing bifunctional epoxy resin is more preferably represented by the following structure: [ka] In the formula, X 1 is alkylene having 2 to 12 carbon atoms, preferably alkylene having 2 to 6 carbon atoms. For example, it is ethylene, propylene, etc., and more preferably ethylene or propylene. 1 is 1 to 22, more preferably 2 to 18, and further preferably 4 to 14. The alkylene may be branched.

[0020] In the present invention, component (B) preferably has an epoxy equivalent of 170 g / eq. or more and 500 g / eq. or less. The lower limit of the epoxy equivalent is more preferably 185 g / eq. or more, and even more preferably 210 g / eq. or more. The upper limit of the epoxy equivalent is more preferably 475 g / eq. or less, and even more preferably 450 g / eq. or less. If the epoxy equivalent is less than the lower limit, the elastic modulus of the cured product may not decrease sufficiently. If the epoxy equivalent exceeds the upper limit, unreacted epoxy groups may remain, which may result in a large change in the elastic modulus during high-temperature storage.

[0021] The amount of component (B) blended is preferably 10 parts by mass or more and 500 parts by mass or less per 100 parts by mass of component (A). The upper limit is more preferably 450 parts by mass or less, and even more preferably 400 parts by mass or less. The lower limit is more preferably 25 parts by mass or more, even more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more. If the amount of component (B) blended is less than the lower limit, the elastic modulus of the cured product may not be sufficiently reduced. If the amount exceeds the upper limit, unreacted epoxy groups may remain, which may result in a large change in elastic modulus during high-temperature storage.

[0022] [(C) Liquid phenolic resin] Component (C) is a phenolic resin that is liquid at 25°C and serves as a curing agent for the epoxy resin. Component (C) is added for the purpose of reacting with the epoxy groups contained in components (A) and (B).

[0023] (C) Liquid phenolic resin is liquid at 25° C. The liquid phenolic resin preferably has a viscosity of 0.1 Pa·s to 500 Pa·s, more preferably 1 Pa·s to 50 Pa·s, at 25° C. If the viscosity is within this range, dispersion in the epoxy resin is easy. In the present invention, the viscosity of the phenolic resin and the epoxy resin is a value measured by a method using a cone-and-plate rotational viscometer as described in JIS Z8803:2011.

[0024] In the present invention, the liquid phenolic resin (C) is characterized by having one or more functional groups containing an unsaturated double bond per molecule. The functional group containing an unsaturated double bond is, for example, an alkenyl group having 2 to 6 carbon atoms, and among these, an allyl group or a vinyl group is preferred.

[0025] The liquid phenolic resin may be any one having a functional group containing the unsaturated double bond, and may be selected from commonly known liquid phenolic resins. For example, a liquid phenolic resin represented by the following formula (1) is more preferred. [ka] In the formula, R 1 are each independently a hydrogen atom or a group selected from a hydroxyl group, an alkenyl group having 2 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms; R 1 At least one of these is an alkenyl group having 2 to 6 carbon atoms, more preferably an allyl group or a vinyl group. n is a number from 0 to 10, preferably a number from 0 to 5, more preferably a number from 1 to 5. X is a divalent linking group selected from the group consisting of the following formulae: [ka] (In the formula, R 2 are each independently a hydrogen atom or a methyl group.

[0026] In formula (1), R 1 is a group selected from a hydrogen atom, a hydroxyl group, an alkenyl group having 2 to 6 carbon atoms such as an allyl group and a vinyl group, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group and a cyclohexyl group, an aryl group having 6 to 12 carbon atoms such as a phenyl group and a tolyl group, and an aralkyl group having 7 to 12 carbon atoms such as a benzyl group and a phenylethyl group.

[0027] Among the liquid phenolic resins represented by the formula (1), allyl group-containing phenolic resins such as bisphenol A allylphenol resins, bisphenol F allylphenol resins, novolac allylphenol resins, aralkyl allylphenol resins, and resorcinol allylphenol resins are preferred in terms of viscosity and adhesive strength. These may be used alone or in combination of two or more.

[0028] The amount of liquid phenolic resin (C) blended is such that the molar equivalent ratio of phenolic hydroxyl groups in component (C) to the combined molar equivalent of epoxy groups in components (A) and (B) is preferably 0.1 to 2.0, more preferably 0.2 to 1.8, and even more preferably 0.4 to 1.5. If this ratio is less than 0.1, unreacted epoxy groups may remain, potentially resulting in reduced adhesion. If it exceeds 2.0, unreacted phenolic hydroxyl groups may remain, potentially resulting in reduced strength during high-temperature storage.

[0029] [(D) Antioxidant] The (D) antioxidant is blended to prevent oxidative degradation of the cured epoxy resin composition when stored at high temperatures. Furthermore, by combining this antioxidant with the (C) liquid phenolic resin, the reaction between the unsaturated double bonds of the (C) component can be suppressed even when stored at high temperatures. This effectively prevents deterioration of bending strength and adhesive strength over time.

[0030] The component (D) may be any commonly known antioxidant. Among them, one or more selected from phenolic antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants are preferred, with phenolic antioxidants being particularly preferred. The melting point of the phenolic antioxidant is preferably 80 to 250°C, more preferably 90 to 240°C, and particularly preferably 100 to 220°C.

[0031] Examples of phenolic antioxidants include n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)acetate, neododecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, dodecyl-2-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)isobutyrate, octadecyl-3-( 3,5-di-t-butyl-4-hydroxyphenyl)isobutyrate, 2-(n-octylthio)ethyl-3,5-di-t-butyl-4-hydroxyphenylacetate, 2-(n-octadecylthio)ethyl-3,5-di-t-butyl-4-hydroxyphenylacetate, 2-(n-octadecylthio)ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2-(2-stearoyloxyethylthio)ethyl-7-(3-methyl-5-t-butyl-4-hydroxyphenyl)heptanoate , 2-hydroxyethyl-3-(3-methyl-5-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3-(3,5-di-tert-butyl-4-hydroxyphenyl)stearyl propionate, 1,3,5-tris[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,1,3-tris(2-methylethyl) 4,4'-butylidenebis(6-tert-butyl-m-cresol), pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-dimethyl-2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)dipropane-1,1'-diyl bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoate], and the like.

[0032] Examples of sulfur-based antioxidants include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate), and 2,2-bis[[3-(dodecylthio)-1-oxopropyloxy]methyl]-1,3-propanediyl bis[3-(dodecylthio)propionic acid].

[0033] Examples of phosphorus-based antioxidants include tridecyl phosphite, triphenyl phosphite, tris(2,4-di-t-butylphenyl)phosphite, 2-ethylhexyldiphenyl phosphite, diphenyltridecyl phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, distearyl pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, 2- [[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]-ethyl]ethanamine, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, and the like.

[0034] The above antioxidants may be used alone or in combination of two or more.

[0035] The amount of component (D) in the epoxy resin composition of the present invention is preferably 0.01 to 20 parts by mass, more preferably 0.05 to 17.5 parts by mass, and even more preferably 0.1 to 15 parts by mass, per 100 parts by mass of component (A). If the amount of component (D) is less than the above lower limit, the strength of the resin may decrease due to oxidative degradation. If the amount exceeds the above upper limit, the strength of the resin may decrease.

[0036] [Other additives] In addition to the components (A) to (D), the epoxy resin composition of the present invention may contain optional additives as needed, provided that the additives do not impair the objects and effects of the present invention. Examples of such additives include (E) a curing accelerator, (F) an inorganic filler, a flame retardant, an ion trapping agent, an adhesion promoter, a stress reducing agent, a colorant, etc.

[0037] [(E) Curing accelerator] The optional component (E) curing accelerator of the present invention may be any accelerator that accelerates the curing reaction between the components (A) and (B) and the component (C), and generally known accelerators such as imidazole curing accelerators, organophosphorus curing accelerators, and tertiary amine curing accelerators can be used.

[0038] Examples of imidazole curing accelerators include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2,4-dimethylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 1,2-diethylimidazole, 2-phenyl-4-methylimidazole, 2,4,5-triphenylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-allyl-4,5-diphenylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0039] Examples of organic phosphorus curing accelerators include phosphines such as triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, and tri(nonylphenyl)phosphine; phosphine-borane complexes such as triphenylphosphine-triphenylborane; phosphonium borate salts such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tri-tert-butylphosphonium tetraphenylborate; and bis(tetrabutylphosphonium) dihydrogenpyromellitate.

[0040] Examples of tertiary amine curing accelerators include tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, and 1,8-diazabicyclo[5.4.0]undecene-7; salts of tertiary amine compounds such as 1,8-diazabicyclo[5.4.0]undecene-7; etc. These may be used alone or in combination of two or more.

[0041] The amount of the (E) curing accelerator blended is preferably 0.01 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the (A) component.

[0042] [(F) Inorganic filler] (F) Inorganic fillers are blended into epoxy resin compositions to improve their resin strength and reduce their thermal expansion. Examples of inorganic fillers include silicas (e.g., fused silica, crystalline silica, cristobalite, etc.), alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, glass fiber, magnesium oxide, etc. The average particle size and shape of these inorganic fillers can be selected depending on the application.

[0043] In order to strengthen the bond strength between the resin and the inorganic filler, it is preferable to use an inorganic filler whose surface has been previously treated with a coupling agent such as a silane coupling agent or a titanate coupling agent.

[0044] Examples of such coupling agents include epoxy silanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino silanes such as N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, reaction products of imidazole and γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane; and mercaptosilanes such as γ-mercaptosilane and γ-episulfidoxypropyltrimethoxysilane.

[0045] The amount of the coupling agent used in the surface treatment and the surface treatment method are not particularly limited.

[0046] The amount of inorganic filler added is preferably 10 to 20,000 parts by mass, and more preferably 30 to 10,000 parts by mass, per 100 parts by mass of the component (A).

[0047] Flame retardants The flame retardant is added for the purpose of imparting flame retardancy. The flame retardant is not particularly limited and any known flame retardant can be used, such as a phosphazene compound, a silicone compound, zinc molybdate-supported talc, zinc molybdate-supported zinc oxide, aluminum hydroxide, magnesium hydroxide, and molybdenum oxide.

[0048] Ion trapping agents The ion trapping agent is added for the purpose of trapping ionic impurities contained in the epoxy resin composition and preventing thermal degradation and moisture absorption degradation. The ion trapping agent is not particularly limited and known agents can be used, such as hydrotalcites, bismuth hydroxide compounds, and rare earth oxides.

[0049] Adhesion promoter The adhesion promoter is added for the purpose of imparting adhesiveness or tackiness (pressure-sensitive adhesiveness). The adhesion promoter is not particularly limited and any known adhesion promoter can be used, such as a urethane resin, a phenol resin, a terpene resin, or a silane coupling agent.

[0050] Among these, silane coupling agents are preferred. Examples of silane coupling agents include n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, β-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxytri(ethyleneoxy)propyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, and the like.

[0051] The amount of additives other than the above components (E) and (F) to be added varies depending on the purpose of the composition, but is usually 5% by mass or less of the total epoxy resin composition excluding the inorganic filler (F).

[0052] The epoxy resin composition of the present invention is preferably liquid at room temperature (25°C). Furthermore, it is preferable that the viscosity at 25°C is 0.1 to 850 Pa s. In the present invention, the viscosity of the epoxy resin composition is a value measured at 25°C by a method using a cone-plate rotational viscometer as described in JIS Z8803:2011.

[0053] The epoxy resin composition of the present invention can be produced by the following method. For example, components (A) to (D) are mixed, stirred, dissolved, and / or dispersed, either simultaneously or separately, with heating as necessary, to obtain a mixture of components (A) to (D). Preferably, a liquid phenolic resin (C) is added to a mixture of components (A), (B), and (D), followed by stirring, dissolving, and / or dispersing to obtain a mixture of components (A) to (D). Depending on the intended use, one or more of a curing accelerator (component (E)) and an inorganic filler, flame retardant, ion trapping agent, adhesion promoter, stress-reducing agent, and colorant (component (F)) may be added and mixed with the mixture of components (A) to (D). The device for mixing, stirring, and dispersing is not particularly limited. For example, a mortar and pestle mixer equipped with a stirring and heating device, a two-roll mill, a three-roll mill, a ball mill, a planetary mixer, or a mass colloider can be used, and these devices may be used in appropriate combination.

[0054] The epoxy resin composition of the present invention can be used as a cured product by curing. The curing conditions for the epoxy resin composition of the present invention are not particularly limited, but may be, for example, heated at a temperature in the range of 60 to 200°C, preferably 80 to 180°C, for 30 minutes to 10 hours, preferably 1 to 5 hours. The epoxy resin composition of the present invention can be cured at a low temperature in a short time. Therefore, it can be cured satisfactorily at a temperature in the range of 70 to 130°C for about 10 minutes to 2 hours.

[0055] The present invention also provides a method for reducing the elastic modulus of a cured product of an epoxy resin composition containing the above-mentioned components (B) and (C) as essential components. This method is characterized by incorporating the above-mentioned components (A) and (D) as essential components in addition to the components (B) and (C) of the epoxy resin composition, and can also suppress decreases in tensile elastic modulus and adhesive strength during high-temperature storage.

[0056] The epoxy resin composition of the present invention has excellent adhesive strength and heat resistance, and therefore can be used as an encapsulant, underfill material, or adhesive in fields such as electrical and electronic equipment components and automotive components. Furthermore, the epoxy resin composition of the present invention has excellent heat resistance and moisture resistance reliability, and therefore can be suitably used in fields such as power semiconductors. In particular, the composition is suitably used for semiconductor devices having a support, a semiconductor element disposed on the support, and a cured product of the epoxy resin composition that encapsulates the semiconductor element, particularly for semiconductor devices in which the epoxy resin composition is used to fill the gap between the semiconductor element and the support. [Example]

[0057] EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In Table 1, the blend amounts are shown in parts by mass. The "molar equivalent ratio" in Table 1 refers to the ratio of the total molar equivalent of phenolic hydroxyl groups (active hydrogen) in component (C) to 1 molar equivalent of the epoxy groups in components (A) and (B).

[0058] The components used in the examples and comparative examples are as follows: (A) Epoxy resin (A) A mixture of bisphenol A epoxy resin and bisphenol F epoxy resin (ZX1059, viscosity 2,000 mPa·s at 25°C, manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent 166 g / eq.)

[0059] (B) Polyalkylene-containing epoxy resin having two epoxy groups per molecule (B1) Polyethylene glycol diglycidyl ether (EX-821, viscosity at 25°C: 40 mPa s, epoxy equivalent: 185 g / eq., manufactured by Nagase ChemteX Corporation, in the following formula, X 1 is ethylene, and n 1 = 4) (B2) Polyethylene glycol diglycidyl ether (EX-830, viscosity at 25°C 70 mPa s, epoxy equivalent 268 g / eq., manufactured by Nagase ChemteX Corporation, in the following formula, X1 is ethylene, and n 1 = 9) (B3) Polyethylene glycol diglycidyl ether (EX-841, viscosity at 25°C 110 mPa s, epoxy equivalent 372 g / eq., manufactured by Nagase ChemteX Corporation, in the following formula, X 1 is ethylene, and n 1 =13) (B4) Polypropylene glycol diglycidyl ether (EX-931, viscosity at 25°C 130 mPa s, epoxy equivalent 471 g / eq., manufactured by Nagase ChemteX Corporation, in the following formula, X 1 is methylethylene, and n 1 = 11) [ka]

[0060] (C) Liquid phenolic resin (C1) Novolac-type allylphenol resin (MEH-8000H, viscosity at 25°C: 1,600 mPa·s, manufactured by UBE Corporation) represented by the following formula: [ka] (n=0-4) (C2) 2,2'-diallylbisphenol A (DABPA, viscosity at 25°C: 20,000 mPa·s, manufactured by Daiwa Chemical Industry Co., Ltd.) represented by the following formula: [ka] (C') Comparative epoxy resin curing agent (C'1) Bisphenol A (solid at 25°C, melting point 158°C, manufactured by Tokyo Chemical Industry Co., Ltd.) [ka]

[0061] (D) Antioxidants (D1) Hindered phenol antioxidant (AO-20, melting point 220°C, manufactured by ADEKA Corporation)

[0062] [Other optional additives] (E) Curing accelerator (E1) Imidazole-based curing accelerator (trade name: 2P4MHZ-PW, manufactured by Shikoku Chemicals Corporation)

[0063] Epoxy resin compositions were prepared by mixing the components in a planetary mixer according to the formulations described in Examples 1 to 17 and Comparative Examples 1 to 4. The resulting epoxy resin compositions were evaluated as follows. The results are shown in Table 1.

[0064] [viscosity] The viscosity of the epoxy resin composition at 25°C was measured in accordance with JIS Z 8803:2011. That is, the viscosity was measured 2 minutes after the sample was set using a cone-plate rotational viscometer (E-type viscometer) at a measurement temperature of 25°C.

[0065] [Tensile modulus of cured product] The epoxy resin composition was poured into a mold and heated at 120°C for 1 hour, then at 180°C for 3 hours to prepare a test sample (cured product) measuring 100 mm x 10 mm and 4 mm thick. The tensile modulus (MPa) of the test sample (cured product) was measured in accordance with JIS K 7161-1:2014 using an EZ TEST (EZ-L, manufactured by Shimadzu Corporation) at a test speed of 500 mm / min, a grip distance of 80 mm, and a gauge length of 40 mm.

[0066] [Tensile modulus retention after high-temperature storage] Test samples (cured products) prepared under the same conditions as those described above for [Tensile modulus of cured product] were stored in an oven set to 180°C for 150 hours and then cooled to 25°C. The tensile modulus (MPa) of the test samples (cured products) was measured in accordance with JIS K 7161-1:2014 using an EZ TEST (EZ-L, manufactured by Shimadzu Corporation) at a test speed of 500 mm / min, a grip distance of 80 mm, and a gauge length of 40 mm. The tensile modulus retention after high-temperature storage was calculated more specifically using the following formula: Tensile modulus after high-temperature storage = [Tensile modulus after storage for 150 hours at 180°C] / [Tensile modulus before storage] x 100 (%)

[0067] [Adhesion retention rate after high temperature storage] The adhesion area is 4mm on a copper frame measuring 10mm x 10mm. 2 An epoxy resin composition was applied so that the temperature was such that a silicon chip was placed on top of it, and the mixture was heated at 120°C for 1 hour and then at 180°C for 3 hours to prepare a test piece. Using this test piece, the shear adhesive strength at room temperature (25°C) was measured using a bond tester DAGE-SERIES-4000PXY (manufactured by DAGE Corporation) to evaluate adhesive strength. The obtained test piece was also stored in an oven at 180°C for 150 hours, and then cooled to 25°C, and the shear adhesive strength was measured. More specifically, the adhesive strength retention rate after high-temperature storage was calculated using the following formula: Adhesion retention rate = [shear adhesive strength after storage for 150 hours at 180°C] / [shear adhesive strength before storage] x 100 (%)

[0068] JPEG2026002226000010.jpg247111

[0069] [Table 2]

[0070] As shown in Table 2 above, an epoxy resin composition that does not contain (B) a polyalkylene-containing epoxy resin exhibits a high tensile modulus of elasticity in the cured product (Comparative Example 1). An epoxy resin composition that does not contain a curing agent does not cure (Comparative Example 2). An epoxy resin composition that contains bisphenol A, which does not have an unsaturated double bond-containing group and is solid at room temperature, instead of the liquid phenolic resin component (C) of the present invention exhibits a high viscosity at 25°C, and the resulting cured product exhibits a high rate of change in tensile modulus upon high-temperature storage and a low adhesive strength retention rate (Comparative Example 4). A cured product obtained from an epoxy resin composition that contains the components (B) and (C) of the present invention but does not contain the antioxidant (D) exhibits a high rate of change in tensile modulus upon high-temperature storage and a low adhesive strength retention rate (Comparative Example 3). In contrast, as shown in Table 1 above, the epoxy resin composition of the present invention has a low viscosity, the resulting cured product exhibits a low tensile modulus, and the change in tensile modulus and the decrease in adhesive strength retention when the cured product is stored at high temperatures are suppressed. [Industrial Applicability]

[0071] The epoxy resin composition of the present invention has low viscosity and provides a cured product with low elasticity. Furthermore, the cured product exhibits low tensile modulus and adhesive strength even when stored at high temperatures. The epoxy resin composition of the present invention can be suitably used as an encapsulant, underfill, or adhesive in fields such as electrical and electronic equipment components and automotive parts.

Claims

1. (A) an epoxy resin other than the following component (B), (B) a polyoxyalkylene-containing epoxy resin having two epoxy groups in one molecule; (C) a phenolic resin that is liquid at 25°C and has one or more functional groups containing an unsaturated double bond in each molecule; and (D) antioxidant An epoxy resin composition comprising:

2. 2. The epoxy resin composition according to claim 1, wherein the component (A) is an epoxy resin having one or more aromatic rings in one molecule.

3. 2. The epoxy resin composition according to claim 1, wherein the component (A) is at least one selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, naphthalene epoxy resins, and aminophenol epoxy resins.

4. 2. The epoxy resin composition according to claim 1, wherein the component (B) has an epoxy equivalent of 170 g / eq. or more and 500 g / eq. or less.

5. 2. The epoxy resin composition according to claim 1, wherein the blending amount of the component (B) is 10 parts by mass or more and 500 parts by mass or less per 100 parts by mass of the epoxy resin (A).

6. 2. The epoxy resin composition according to claim 1, wherein in component (C), the functional group containing an unsaturated double bond is an alkenyl group having 2 to 6 carbon atoms.

7. The component (C) is a compound represented by the following formula (1): 【Chemistry 1】 (In the formula, R １ are each independently a hydrogen atom or a group selected from a hydroxyl group, an alkenyl group having 2 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms; R １ At least one of the groups is the alkenyl group, n is a number from 0 to 10, and X is a group of the following formula: 【Chemistry 2】 is a divalent linking group selected from the group consisting of ２ are each independently a hydrogen atom or a methyl group. The epoxy resin composition according to claim 1, wherein

8. 2. The epoxy resin composition according to claim 1, wherein the blending amount of the component (D) is 0.01 to 20 parts by mass per 100 parts by mass of the component (A).

9. 2. The epoxy resin composition according to claim 1, wherein the molar equivalent ratio of phenolic hydroxyl groups contained in component (C) relative to 1 molar equivalent of the total of epoxy groups contained in components (A) and (B) is 0.1 to 2.

0.

10. 2. The epoxy resin composition according to claim 1, wherein the component (D) is at least one selected from the group consisting of phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

11. 2. The epoxy resin composition according to claim 1, having a viscosity at 25°C of 0.01 to 850 Pa·s.

12. An adhesive comprising the epoxy resin composition according to any one of claims 1 to 11.

13. An underfill agent comprising the epoxy resin composition according to any one of claims 1 to 11.

14. A semiconductor device comprising a cured product of the epoxy resin composition according to any one of claims 1 to 11.

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