Two-component epoxy resin composition

Abstract

To provide a two liquid type epoxy resin composition which has low viscosity and from which precipitation of an inorganic filler is scarcely generated, which is excellent in thermal shock resistance and in moisture resistance reliability, and from which a highly adhesive and high strength cured product is obtained even under high temperature and highly humid condition.SOLUTION: A two liquid type epoxy resin composition consists of a main agent and a curative. The main agent contains a liquid epoxy resin (A) and an inorganic filler (B). The curative contains a liquid aromatic amine-based curative (C) and the inorganic filler (B). The inorganic filler (B) is subjected to a surface treatment by one or more selected from a group consisting of an aminosilane coupling agent, an epoxysilane coupling agent, and the like.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a two-component epoxy resin composition.

Background Art

[0002] In recent years, power modules have been used in a wide range of fields such as hybrid vehicles, electric vehicles, railways, and generators. Recently, there has been an increasing demand for higher performance of power modules, such as an increase in rated voltage and rated current, and an expansion of the operating temperature range.

[0003] The package structure of a power module is such that a power semiconductor element is mounted on a heat dissipation base plate via an insulating substrate, and a case is adhered to the base plate. As a sealing member for the power module, silicone gel is generally used (Patent Document 1).

[0004] However, in recent years, in use under high-temperature environments, due to insufficient heat resistance of the silicone gel, the gel hardens and cracks occur, and also, due to the decomposition of the silicone gel, low-volatile components are generated to form bubbles, resulting in peeling between the silicone gel and the insulating substrate. As a result, problems such as a decrease in the insulation reliability of the power module have occurred.

[0005] For the purpose of solving this problem, liquid epoxy resin has been studied as a sealing material to replace silicone gel (Patent Document 2). Generally, liquid epoxy resin used as a sealing material for power modules contains a large amount of inorganic fillers to approach the linear expansion coefficient of the insulating substrate in order to suppress warping after sealing.

[0006] As a result, the viscosity of the liquid epoxy resin becomes high, and problems such as voids not escaping after sealing and cracks and peeling occurring arise.

[0007] In addition, in conventional liquid epoxy resin encapsulants, an acid anhydride curing agent is used for the purpose of reducing viscosity (Patent Document 3). However, using an acid anhydride curing agent causes a problem that the inorganic filler easily settles during storage. For the purpose of preventing sedimentation, it has been considered to blend the inorganic filler only in the main agent, but there are problems that the dispersion becomes poor during mixing and the curing characteristics are likely to vary. In addition, problems such as hydrolysis of the resin cured under high temperature and high humidity conditions, peeling from the substrate, and resin cracking also occur.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] Accordingly, an object of the present invention is to provide a two-component epoxy resin composition in which the composition has a low viscosity, sedimentation of the inorganic filler hardly occurs, it has excellent thermal shock resistance and moisture resistance reliability, and a cured product having high adhesion and high strength can be obtained even under high temperature and high humidity conditions.

Means for Solving the Problems

[0010] In view of such a situation, as a result of intensive research, the present inventors have found that a composition containing a liquid epoxy resin, an inorganic filler surface-treated with a specific silane coupling agent, and a liquid aromatic amine-based curing agent can solve the above problems, and have completed the present invention.

[0011] That is, the present invention provides the following two-component epoxy resin composition. [1] A two-component epoxy resin composition comprising a main agent and a curing agent, The main agent contains (A) a liquid epoxy resin and (B) an inorganic filler, The curing agent contains (C) a liquid aromatic amine curing agent and (B) an inorganic filler, The (B) inorganic filler is surface-treated with one or more selected from the group consisting of an aminosilane coupling agent, an epoxysilane coupling agent, a vinylsilane coupling agent, an acrylsilane coupling agent, a mercaptosilane coupling agent, a triazine functional group type silane coupling agent, an isocyanate functional group type silane coupling agent, an isocyanuric acid functional group type silane coupling agent, a benzotriazole functional group type silane coupling agent, an acid anhydride functional group type silane coupling agent, an azasilacyclopentane functional group type silane coupling agent, an imidazole functional group type silane coupling agent, and an unsaturated group-containing silane coupling agent. Two-component epoxy resin composition.

[0012] [2] The two-component epoxy resin composition according to [1], wherein the component (A) contains one or more selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, and aminophenol type epoxy resin.

[0013] [3] The two-component epoxy resin composition according to [1] or [2], wherein the component (C) is one or more selected from the group consisting of aromatic amine curing agents represented by the following formulas (1), (2), and (3). [Chemical formula] (In the formula, R 1 ~R 4 is a group selected from a hydrogen atom, the same or different monovalent hydrocarbon groups having 1 to 6 carbon atoms, CH3S-, and CH3CH2S-. n is a number from 1 to 10.) [4] The two-component epoxy resin composition according to any one of [1] to [3], wherein the component (B) has an average particle size of 1 to 100 μm. [5] The main agent is a two-component epoxy resin composition according to any one of [1] to [4], wherein (B) an inorganic filler is 150 to 1500 parts by mass with respect to 100 parts by mass of (A) a liquid epoxy resin. [6] The curing agent is a two-component epoxy resin composition according to any one of [1] to [5], wherein (B) an inorganic filler is 150 to 1900 parts by mass with respect to 100 parts by mass of (C) a liquid aromatic amine-based cured product. [7] The two-component epoxy resin composition according to any one of [1] to [6], wherein the ratio of the viscosity of the curing agent at 25 °C to the viscosity of the main agent at 25 °C is 0.5 to 1.7.

Advantages of the Invention

[0014] According to the two-component epoxy resin composition of the present invention, the composition has a low viscosity and the sedimentation of the inorganic filler hardly occurs, and it is excellent in thermal shock resistance and moisture resistance reliability, and a cured product with high adhesion and high strength can be obtained even under high temperature and high humidity conditions.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present invention will be described in detail. In the two-component epoxy resin composition of the present invention, the (A) liquid epoxy resin is an epoxy resin that is liquid at room temperature (25 °C). Examples of the (A) liquid epoxy resin include liquid bisphenol A type epoxy resin, liquid bisphenol F type epoxy resin, liquid naphthalene type epoxy resin, liquid aminophenol type epoxy resin, liquid hydrogenated bisphenol type epoxy resin, liquid alcohol ether type epoxy resin, liquid fluorene type epoxy resin, and liquid alicyclic epoxy resin. These may be used alone or in combination of two or more. Among them, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, and aminophenol type epoxy resin are preferred.

[0016] For the purpose of increasing the heat resistance of the cured product in addition to the above liquid epoxy resin, generally known epoxy resins that are solid at room temperature (25°C) can be used. Examples include bisphenol type epoxy resins such as 3,3’,5,5’-tetramethyl-4,4’-biphenol type epoxy resin and 4,4’-biphenol type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, stilbene type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, trisphenol alkane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, alicyclic epoxy resin, diglycidyl ether compounds of polyfunctional phenols and polycyclic aromatics such as anthracene, and phosphorus-containing epoxy resins obtained by introducing phosphorus compounds into these, silicone-modified epoxy resins, and the like. These may be used alone or in combination of two or more.

[0017] In the two-component epoxy resin composition of the present invention, the inorganic filler as the component (B) is a filler for the above components (A) and (C), and is added to reduce the thermal expansion coefficient of the composition and improve the moisture resistance reliability.

[0018] Examples of the inorganic filler include silicas such as fused silica, crystalline silica, cristobalite, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, glass fiber, magnesium oxide, and the like. These may be used alone or in combination of two or more. The average particle diameter and shape of these inorganic fillers can be selected according to the application. Among them, spherical alumina, spherical fused silica, glass fiber, etc. are preferred.

[0019] In addition, the inorganic filler is surface-treated with one or more selected from the group consisting of an aminosilane coupling agent, an epoxy silane coupling agent, a vinyl silane coupling agent, a methacryl silane coupling agent, an acrylic silane coupling agent, a mercapto silane coupling agent, a triazine functional group type silane coupling agent, an isocyanate functional group type silane coupling agent, an isocyanuric acid functional group type silane coupling agent, a benzotriazole functional group type silane coupling agent, an acid anhydride functional group type silane coupling agent, an azasilacyclopentane functional group type silane coupling agent, an imidazole functional group type silane coupling agent, and an unsaturated group-containing silane coupling agent.

[0020] Examples of the aminosilane coupling agent include N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and the like.

[0021] Examples of the epoxy silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, and the like.

[0022] Examples of the vinyl silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, and the like.

[0023] Examples of the methacryl silane coupling agent include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 8-methacryloxyoctyltrimethoxysilane, and the like.

[0024] Examples of the acrylic silane coupling agent include 3-acryloxypropyltrimethoxysilane and the like.

[0025] Examples of the mercapto silane coupling agent include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like.

[0026] Among them, amino silane coupling agents and epoxy silane coupling agents are preferred.

[0027] When surface-treating the inorganic filler with the silane coupling agent as described above, it can be carried out by a conventional method.

[0028] These silane coupling agents exhibit the effects of the present invention because, compared with those having an organic group that is non-polar and has no reactive functional group such as an alkyl silane coupling agent, the organic group is a reactive functional group, and they are excellent in dispersibility with the liquid epoxy resin and the liquid aromatic amine curing agent. Also, it is a feature for obtaining the effects of the present invention that the inorganic filler has been surface-treated in advance with the above silane coupling agent and these are not blended separately.

[0029] Moreover, the average particle size of the component (B) is preferably 1 to 100 μm, more preferably 5 to 90 μm, and even more preferably 10 to 80 μm. Here, the average particle size is the volume-based 50% cumulative distribution diameter measured by the dynamic light scattering method using a laser beam.

[0030] In the two-component epoxy resin composition of the present invention, the liquid aromatic amine curing agent as the component (C) is a curing agent for the above component (A), and is a liquid amine compound having an aromatic ring, which is excellent in heat resistance and storage stability. The liquid aromatic amine curing agent is liquid at room temperature (25°C), and preferably includes liquid aromatic amine curing agents represented by the following formulas (1) to (3).

[0031] [Chemistry]

[0032] (In the formula, R 1 ~R 4 is a group selected from a hydrogen atom, a monovalent hydrocarbon group having 1 to 6 carbon atoms which may be the same or different, CH3S-, and CH3CH2S-. n is a number from 1 to 10.)

[0033] R 1 ~R 4 When ~R

[0034] is a monovalent hydrocarbon group, it may be linear or branched. Specifically, examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a 1-methylbutyl group, a 1-ethylpropyl group, a 1,1-dimethylpropyl group, a 2,2-dimethylpropyl group, a hexyl group, and the like.

[0035] For the purpose of increasing the heat resistance of the cured product in addition to the above liquid aromatic amine curing agent, generally known aromatic amine curing agents that are solid at room temperature (25 °C) can be used. Examples include 4,4'-methylenebis(2-ethyl-6-methylaniline), 2,2'-diisopropyl-6,6'-dimethyl-4,4'-methylenedianiline, 2,2',6,6'-tetraisopropyl-4,4'-methylenedianiline, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(3-chloro-2,6-diethylaniline), 1,3-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4,6-trimethyl-1,3-phenylenediamine, 3-aminobiphenyl, 3-amino-4-methoxybiphenyl, 2-aminofluorene, 2-amino-9-fluorenone, 2,7-diaminofluorene, 3-aminobenzophenone, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4-diaminobenzophenone, 3,3'-diaminobenzophenone, and the like. These may be used alone or in combination of two or more.

[0036] If the solid aromatic amine curing agent is compounded as it is, the resin viscosity may increase and the workability may be significantly deteriorated. Therefore, it is preferably melt-mixed with the above liquid aromatic amine curing agent in advance.

[0037] (D) Other additives In addition to the components (A) to (C) above, the two-component epoxy resin composition of the present invention can be added with the component (D), which is other additives, as necessary within a range that does not impair the object and effect of the present invention. Such additives include curing accelerators, flame retardants, ion trap agents, antioxidants, adhesion aids, low stress agents, defoaming agents, and the like.

[0038] The above-mentioned curing accelerator is added to promote the curing reaction between the liquid epoxy resin and the liquid aromatic amine curing agent. There is no particular limitation on the curing accelerator as long as it can promote the curing reaction. For example, phosphorus compounds such as triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, tri(nonylphenyl)phosphine, triphenylphosphine·triphenylborane, and tetraphenylphosphine·tetraphenylborate; tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, and 1,8-diazabicyclo[5.4.0]undecene-7; imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole, etc. can be mentioned. These can be used alone or in combination of two or more.

[0039] The above-mentioned flame retardant is added for the purpose of imparting flame retardancy. There is no particular limitation on the flame retardant, and all known ones can be used. For example, phosphazene compounds, silicone compounds, talc supported with zinc molybdate, zinc oxide supported with zinc molybdate, aluminum hydroxide, magnesium hydroxide, molybdenum oxide, etc. can be mentioned. These can be used alone or in combination of two or more.

[0040] The above-mentioned ion trap agent is added for the purpose of capturing ionic impurities contained in the resin composition and preventing thermal degradation and moisture absorption degradation. There is no particular limitation on the ion trap agent, and all known ones can be used. For example, hydrotalcites, bismuth hydroxide compounds, rare earth oxides, etc. can be mentioned. These can be used alone or in combination of two or more.

[0041] The antioxidant is added for the purpose of preventing oxidative degradation of the two-component epoxy resin composition. There is no particular limitation on the antioxidant, and examples thereof include phenol-based antioxidants such as 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-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, ethyl-α-(4-hydroxy-3,5-di-t-butylphenyl)isobutyrate, octadecyl-α-(4-hydroxy-3,5-di-t-butylphenyl)isobutyrate, octadecyl-α-(4-hydroxy-3,5-di-t-butyl-4-hydroxyphenyl)propionate, 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 7-(3-methyl-5-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]; sulfur-based antioxidants such as dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, ditridecyl 3,3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate);Phosphorus-based antioxidants such as tridecyl phosphite, triphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, 2-ethylhexyl diphenyl phosphite, diphenyl tridecyl 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 can be mentioned. These may be used alone or in combination of two or more. ;

[0042] The above adhesion aid is compounded for the purpose of enhancing the adhesiveness to a silicon wafer, a metal substrate or an organic substrate. It is not particularly limited and known ones can be used. For example, coupling agents such as silane coupling agents and titanate coupling agents can be compounded, and among them, silane coupling agents are preferable. Examples of such coupling agents include epoxy-functional alkoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, amino-functional alkoxysilanes such as N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, mercapto-functional alkoxysilanes such as γ-mercaptopropyltrimethoxysilane, and amine-functional alkoxysilanes such as γ-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane. These may be used alone or in combination of two or more.

[0043] The low-stress agent is added for the purpose of reducing the stress of the two-component epoxy resin composition, and any known agents can be used without particular limitation. Examples of the low-stress agent include silicone compounds such as silicone oil, silicone resin, and silicone-modified phenolic resin; and thermoplastic elastomers such as styrene resin and acrylic resin. These may be used alone or in combination of two or more.

[0044] The defoaming agent is added for the purpose of improving the defoaming property when the two-component epoxy resin composition is cast. Examples of the defoaming agent include dimethylpolysiloxane, polyoxyalkylene alkyl ether, synthetic resin particles, uncoated silica, or a mixture of two or more of these.

[0045] The blending amount of component (D) varies depending on the intended use of the two-component epoxy resin composition, but is usually an amount of 10% by mass or less of the entire two-component epoxy resin composition.

[0046] [Method for preparing the mixture] The two-component epoxy resin composition of the present invention can be prepared by the following method. For example, the main agent is obtained by mixing, stirring, dissolving, and / or dispersing (A) liquid epoxy resin and (B) inorganic filler while performing heat treatment as necessary, thereby obtaining a mixture of components (A) and (B). Further, at least one of the additives (D) such as a curing accelerator, a flame retardant, an ion trap agent, an antioxidant, an adhesion aid, a low-stress agent, and a defoaming agent may be added to the mixture of components (A) and (B) and mixed. The curing agent is also obtained by mixing, stirring, dissolving, and / or dispersing (B) inorganic filler and (C) liquid aromatic amine-based curing agent while performing heat treatment as necessary, thereby obtaining a mixture of components (B) and (C). Further, at least one of the additives (D) such as a curing accelerator, a flame retardant, an ion trap agent, an antioxidant, an adhesion aid, a low-stress agent, and a defoaming agent may be added to the mixture of components (B) and (C) and mixed. Each of the components (A) to (D) may be used alone or in combination of two or more.

[0047] The main agent and the curing agent are mixed before use. The method for preparing the mixture and the apparatus for mixing, stirring, and dispersing are not particularly limited. Specifically, for example, a Lycra machine equipped with a stirring and heating device, a two-roll mill, a three-roll mill, a ball mill, a planetary mixer, or a mascoloider, etc. may be mentioned, and these apparatuses may be used in appropriate combinations.

[0048] In the two-component epoxy resin composition of the present invention, it is preferable that the inorganic filler (B) is 150 to 1500 parts by mass, more preferably 200 to 1200 parts by mass, and even more preferably 250 to 1000 parts by mass with respect to 100 parts by mass of the liquid epoxy resin (A) in the main agent. Within such a range, the main agent has a low viscosity and sedimentation of the inorganic filler hardly occurs. The main agent preferably has a viscosity of 1 to 850 Pa·s at 25°C according to JIS K 7117-1:1999.

[0049] In the two-component epoxy resin composition of the present invention, it is preferable that the inorganic filler (B) is 150 to 1900 parts by mass, more preferably 200 to 1700 parts by mass, and even more preferably 250 to 1500 parts by mass with respect to 100 parts by mass of the liquid aromatic amine-based cured product (C) in the curing agent. Within such a range, the curing agent has a low viscosity and sedimentation of the inorganic filler hardly occurs. The curing agent preferably has a viscosity of 1 to 850 Pa·s at 25°C according to JIS K 7117-1:1999.

[0050] In the two-component epoxy resin composition of the present invention, the mixing ratio of the main agent and the curing agent is preferably such that the inorganic filler (B) in the curing agent is 150 to 1500 parts by mass and the liquid aromatic amine-based curing agent (C) is 10 to 300 parts by mass with respect to 100 parts by mass of the liquid epoxy resin (A) in the main agent. Within such a range, excellent thermal shock resistance and moisture resistance reliability can be obtained, and a cured product with high adhesion and high strength can be obtained even under high temperature and high humidity conditions.

[0051] (C) The compounding quantity of the liquid aromatic amine-based curing agent is such that the equivalent of all amino groups in the aromatic amine-based curing agent with respect to 1 equivalent of all epoxy groups in component (A) and other epoxy resins is preferably 0.7 to 1.5, more preferably 0.7 to 1.2, still more preferably 0.7 to 1.1, and particularly preferably 0.85 to 1.05. If the equivalent is less than 0.7, unreacted epoxy groups may remain, which may cause a decrease in the glass transition temperature or a decrease in adhesion. If it exceeds 1.5, the cured product becomes hard and brittle, and cracks may occur during reflow or temperature cycling.

[0052] In the two-component epoxy resin composition of the present invention, the ratio of the viscosity of the curing agent at 25°C to the viscosity of the main agent at 25°C is preferably 0.5 to 1.7. When the viscosity ratio is within this range, the mixing of the main agent and the curing agent components becomes easy and the dispersibility is good.

[0053] The curing conditions of the two-component epoxy resin composition of the present invention are not particularly limited. For example, it can be carried out by first performing oven curing at 60 to 120°C for 1 hour or more, and then at 130 to 200°C for 1 hour or more.

[0054] The two-component epoxy resin composition of the present invention can be used in various applications such as in-vehicle semiconductors and power semiconductors. Among them, it is preferably used in a semiconductor device having a support, a semiconductor element disposed on this support, and a cured product of an epoxy resin composition for sealing the semiconductor element. The types of the semiconductor element and the support are not particularly limited and can be selected from those generally used in the field of semiconductor devices. The method of filling the gap between the semiconductor element and the support with the epoxy resin composition and the method of curing the epoxy resin composition after filling are not particularly limited and can be carried out by known techniques.

[0055] In particular, according to the two-component epoxy resin composition of the present invention, it has a low viscosity and is less likely to cause sedimentation, is excellent in thermal shock resistance and moisture resistance reliability, and a cured product with high adhesion and high strength can be obtained even under high temperature and high humidity conditions. Therefore, it can be suitably used for encapsulating power module semiconductor elements. Such a package structure of a power module is, for example, a structure in which a power semiconductor element is mounted on a heat dissipation base plate via an insulating substrate serving as a support, and a case is adhered to the base plate.

Examples

[0056] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. For Examples 1 to 22 and Comparative Examples 1 to 7, the following components were blended in the compositions shown in Tables 1 to 4 to prepare a main agent and a curing agent, and a two-component epoxy resin composition was obtained. In Tables 1 to 4, the amounts of the respective components are shown in parts by mass.

[0057] (A) Liquid epoxy resin (1) Liquid epoxy resin (A1): Bisphenol A type epoxy resin (YD-8125, viscosity at 25°C: 3900 to 5300 mPa·s; manufactured by Nippon Steel Chemical & Material Co., Ltd.) (2) Liquid epoxy resin (A2): Bisphenol F type epoxy resin (YDF-8170, viscosity at 25°C: 1000 to 1500 mPa·s; manufactured by Nippon Steel Chemical & Material Co., Ltd.) (3) Liquid epoxy resin (A3): Naphthalene type epoxy resin (HP4032D, viscosity at 25°C: 20 to 30 Pa·s; manufactured by DIC Corporation) (4) Liquid epoxy resin (A4): Aminophenol type trifunctional epoxy resin (jER630, viscosity at 25°C: 500 to 1500 mPa·s; manufactured by Mitsubishi Chemical Corporation)

[0058] (A’) Epoxy resin for comparative example (1) Epoxy resin (A’1): Bisphenol A type epoxy resin (jER1001, solid at 25°C; manufactured by Mitsubishi Chemical Corporation)

[0059] (B) Inorganic filler (1) Inorganic filler (B1): Spherical silica with an average particle size of 15 μm surface-treated with 3-glycidoxypropyltrimethoxysilane (2) Inorganic filler (B2): Spherical silica with an average particle size of 15 μm surface-treated with N-phenyl-3-aminopropyltrimethoxysilane (3) Inorganic filler (B3): Spherical silica with an average particle size of 15 μm surface-treated with 3-acryloxypropyltrimethoxysilane (4) Inorganic filler (B4): Spherical silica with an average particle size of 15 μm surface-treated with 3-trimethoxysilylpropyl succinic anhydride (5) Inorganic filler (B5): Spherical silica with an average particle size of 50 μm surface-treated with 3-glycidoxypropyltrimethoxysilane (6) Inorganic filler (B6): Spherical silica with an average particle size of 80 μm surface-treated with 3-glycidoxypropyltrimethoxysilane

[0060] (B’) Inorganic filler for comparative example (1) Inorganic filler (B’1): Spherical silica with an average particle size of 15 μm (2) Inorganic filler (B’2): Spherical silica with an average particle size of 15 μm surface-treated with hexyltrimethoxysilane

[0061] (C) Liquid aromatic amine curing agent (1) Liquid aromatic amine curing agent (C1): 3,3’-diethyl-4,4’-diaminodiphenylmethane (Kayhard AA, viscosity at 25°C: 2000 - 3000 mPa·s; manufactured by Nippon Kayaku Co., Ltd.) (2) Liquid aromatic amine curing agent (C2): Diethyltoluenediamine (Ethan Cure 100, viscosity at 25°C: 100 - 300 mPa·s; manufactured by Albemarle Corporation) (3) Liquid aromatic amine curing agent (C3): Dimethylthiotoluenediamine (Heart Cure 30, viscosity at 25°C: 800 - 1000 mPa·s; manufactured by Kumiai Chemical Industry Co., Ltd.) (4) Liquid aromatic amine curing agent (C4): Polytetramethylene oxide - di-p-aminobenzoate (Elastmer 650P, viscosity at 25°C: 5 - 10 Pa·s; manufactured by Kumiai Chemical Industry Co., Ltd.)

[0062] (C’) Hardener for Comparative Example (1) Alicyclic amine hardener (C’1): 1,3-bis(aminomethyl)cyclohexane (1,3-BAC, viscosity at 25 °C: 5 - 30 mPa·s; manufactured by Mitsubishi Gas Chemical Company) (2) Aromatic amine hardener (C’2): 4,4’-diamino-3,3’-diethyl-5,5’-dimethyldiphenylmethane (Curehard MED-J, solid at 25 °C; manufactured by Kumiai Chemical Industry Co., Ltd.) (3) Liquid acid anhydride hardener: Ricaid MH (1-methylhexahydrophthalic anhydride, viscosity at 25 °C: 25 - 100 mPa·s; manufactured by Shin Nippon Rika Co., Ltd.)

[0063] (D) Other components (1) Defoaming agent (D1): Oil compound type defoaming agent (KS-66, manufactured by Shin-Etsu Chemical Co., Ltd.) (2) Curing accelerator (D2): 2-ethyl-4-methylimidazole (2E4MZ, manufactured by Shikoku Chemicals Corporation) (3) Silane coupling agent (D3): 3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0064] [Evaluation] For each of the obtained compositions, tests were conducted according to the evaluation methods shown below. The results are shown in Tables 1 - 4. (1) Measurement of viscosity In accordance with JIS K 7117-1:1999, the viscosities of the main agent and the hardener at 25 °C were measured. That is, at a measurement temperature of 25 °C, using a B-type viscometer, the sample was set and the viscosity after 2 minutes was measured. Viscosity less than 500 Pa·s was marked as ○, viscosity between 500 Pa·s and less than 1250 Pa·s was marked as △, and viscosity 1250 Pa·s or more was marked as ×, as shown in Tables 1 - 4.

[0065] (2) Confirmation of storage stability The main agent and the hardener were stored in an oven at 40 °C for 1 month. After storage, the viscosity was measured using a B-type viscometer, and the viscosity of the sample after 2 minutes was measured. The thickening rate was calculated from the viscosity after storage at 40 °C and the initial viscosity, and is shown in Tables 1 - 4.

[0066] (3) Sedimentation The main agent and the curing agent were stored in an oven at 40 °C for one month. After storage, the resin was taken out of the container and the bottom was checked. If there was no sedimentation layer at the bottom, it was marked as ○; if there was a sedimentation layer, it was marked as ×.

[0067] (4) Viscosity ratio of the main agent to the curing agent From the viscosities of the main agent and the curing agent measured in (1) above, the viscosity ratio of the main agent to the curing agent (the ratio of the viscosity of the curing agent to the viscosity of the main agent) was calculated and listed in Tables 1 to 4.

[0068] (Curing sample preparation conditions) For Examples 1 to 22 and Comparative Examples 1 to 7, after preparing the main agent and the curing agent, the two-component epoxy resin composition was molded at 120 °C for 1 hour and then at 165 °C for 2 hours without delay to prepare test pieces for the following tests (5) to (7).

[0069] (5) Flexural strength It was measured using the cured product prepared under the above curing conditions in accordance with JIS K 6911:2006.

[0070] (6) Heat cycle test (heat resistance) Using a Cu lead frame with a PPS frame sized 50×70 mm, the compositions prepared in the examples and comparative examples were injected at 80 °C to a thickness of 5 mm, molded at 120 °C for 1 hour and then at 165 °C for 2 hours to obtain molded products. Using the obtained molded products, they were subjected to a heat cycle test (holding at -65 °C for 30 minutes and at 150 °C for 30 minutes as one cycle, repeating 1,000 cycles), and the peeling state between the resin and the Cu lead frame after the heat cycle test was confirmed using an ultrasonic inspection device. The number of molded products with peeling or cracks among a total of 10 molded products was counted.

[0071] (7) Damp heat reliability test Using a Cu lead frame with a PPS frame sized 50×70 mm, the compositions prepared in the examples and comparative examples were injected at 80 °C to a thickness of 5 mm, molded at 120 °C for 1 hour and then at 165 °C for 2 hours to obtain molded articles. Using the obtained molded articles, a moisture resistance reliability test (exposed for 24 hours under saturated water vapor at 121 °C and 2.03×10 5 Pa) was conducted, and the peeling state between the resin and the Cu lead frame after the moisture resistance reliability test was confirmed using an ultrasonic inspection device. The number of molded articles with peeling or cracks was counted among a total of 10 molded articles.

[0072]

Table 1

[0073]

Table 2

[0074]

Table 3

[0075]

Table 4

Claims

1. A two-component epoxy resin composition comprising a main agent and a curing agent, wherein the main agent contains (A) a liquid epoxy resin and (B) an inorganic filler, the curing agent contains (C) a liquid aromatic amine curing agent and (B) an inorganic filler, the (B) inorganic filler is surface-treated with one or more selected from the group consisting of an aminosilane coupling agent, an epoxysilane coupling agent, a vinylsilane coupling agent, an acrylicsilane coupling agent, a mercaptosilane coupling agent, a triazine functional group type silane coupling agent, an isocyanate functional group type silane coupling agent, an isocyanuric acid functional group type silane coupling agent, a benzotriazole functional group type silane coupling agent, an acid anhydride functional group type silane coupling agent, an azasilacyclopentane functional group type silane coupling agent, an imidazole functional group type silane coupling agent, and an unsaturated group-containing silane coupling agent, the (B) inorganic filler has an average particle size of 1 to 100 μm, the (C) liquid aromatic amine curing agent is represented by the following formulas (1), (2), and (3): 【Chemical 1】 (In the formula, R 1 to R 4 are a hydrogen atom, a monovalent hydrocarbon group having the same or different carbon numbers of 1 to 6, a group selected from CH 3 S- and CH 3 CH 2 S-. n is a number from 1 to 10.) and is one or more selected from the group consisting of aromatic amine curing agents, in the main agent, (B) the inorganic filler is 150 to 1500 parts by mass with respect to 100 parts by mass of (A) the liquid epoxy resin, in the curing agent, (B) the inorganic filler is 150 to 1500 parts by mass with respect to 100 parts by mass of (C) the liquid aromatic amine curing agent, and the viscosity at 25 ° C is less than 500 Pa·s, A two-component epoxy resin composition.

2. The two-component epoxy resin composition according to Claim 1, wherein (B) the inorganic filler is 150 to 787 parts by mass with respect to 100 parts by mass of (C) the liquid aromatic amine curing agent.

3. The two-component epoxy resin composition according to Claim 1 or 2, wherein the (A) component contains one or more selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, and aminophenol type epoxy resin.

4. The two-component epoxy resin composition according to Claim 1 or 2, wherein the ratio of the viscosity of the curing agent at 25 ° C to the viscosity of the main agent at 25 ° C is 0.5 to 1.7.

Images