Epoxy resin composition

Abstract

To provide an epoxy resin composition containing a solid dispersion type epoxy resin curing agent and a filler which achieves excellent uniformity of a cured product.SOLUTION: An epoxy resin composition contains (A) an epoxy compound having a molecular weight of less than 270, (B) a solid dispersion type epoxy resin curing agent, and (C) a filler.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an epoxy resin composition. [Background technology]

[0002] 2. Description of the Related Art Thermosetting resin compositions containing epoxy resins that exhibit high reliability have been used as sealing agents, insulating materials, conductive adhesives, and heat dissipation pastes for semiconductor elements. In recent years, the amount of heat generated by semiconductor elements has increased as they have become larger, thinner, and more highly integrated. This has led to an increase in the importance of stress relief and heat dissipation design for semiconductor elements.

[0003] Patent Documents 1 and 2 disclose epoxy resin sealants made of epoxy resin compositions that contain a large amount of inorganic filler and have fluidity at room temperature, and can reduce wafer warpage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5574237 [Patent Document 2] Patent No. 6090614 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Documents 1 and 2 disclose epoxy resin sealants that are made of epoxy resin compositions containing a large amount of a filler and a solid-dispersion type epoxy resin curing agent. However, when a cross section of a conventionally disclosed epoxy resin composition containing a solid-dispersed epoxy resin curing agent is observed after curing, many regions are observed in which no filler of a size corresponding to the particle size of the solid-dispersed epoxy resin curing agent is present, and the uniformity of the cured product is poor.

[0006] In view of the above-mentioned problems in the prior art, an object of the present invention is to provide an epoxy resin composition which contains a filler and gives a cured product with good uniformity. [Means for solving the problem]

[0007] The occurrence of regions in the cross section of the cured product where no filler is present is due to an increase in the viscosity of the epoxy resin composition caused by a curing reaction occurring before a portion of the solid-dispersed epoxy resin curing agent dissolves in the epoxy resin composition, resulting in a decrease in the fluidity of the epoxy resin composition containing the filler. Therefore, the present inventors have conducted extensive research to solve the problems of the conventional techniques described above, and have found that the solubility of a solid-dispersed epoxy resin curing agent can be increased by specifying the molecular weight of an epoxy resin, thereby solving the above-mentioned problems, thereby completing the present invention. That is, the present invention is as follows.

[0008] [1] (A) an epoxy compound having a molecular weight of less than 270; (B) a solid dispersion type epoxy resin curing agent; (C) a filler; An epoxy resin composition comprising: [2] (B) the solid dispersion type epoxy resin curing agent; Liquid bisphenol A type epoxy resin, The epoxy resin composition according to the above item [1], wherein a mixture of the above in a mass ratio of 1:1 has an exothermic peak temperature of 100°C or higher and 200°C or lower when measured by DSC at a heating rate of 2°C / min. [3] The (B) solid dispersion type epoxy resin curing agent is a microcapsule type curing agent. The epoxy resin composition according to [1] or [2] above. [4] The mass ratio of the (C) filler is 30% by mass or more and 98% by mass or less. The epoxy resin composition according to [1] or [2] above. [5] The (A) epoxy compound has a molecular weight of 210 or less. The epoxy resin composition according to [1] or [2] above. [6] The (A) epoxy compound has an aromatic ring or an alicyclic structure in its structure. The epoxy resin composition according to [1] or [2] above. [7] The mass ratio of the (C) filler is 30% by mass or more and 98% by mass or less. The epoxy resin composition according to [3] above. [8] The (A) epoxy compound has a molecular weight of 210 or less. The epoxy resin composition according to [7] above. Effect of the Invention

[0009] According to the present invention, in an epoxy resin composition containing a solid dispersion-type epoxy resin curing agent and a filler, excellent uniformity of the cured product can be achieved. [Brief description of the drawings]

[0010] [Figure 1] 1 shows a cross-sectional view of the cured product of Comparative Example 3. [Diagram 2] 1 shows a cross-sectional view of the cured product of Example 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail. The following embodiments are merely illustrative for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be modified appropriately within the scope of the gist thereof.

[0012] [Epoxy resin composition] The epoxy resin composition of the present embodiment comprises: (A) an epoxy compound having a molecular weight of less than 270; (B) a solid dispersion type epoxy resin curing agent; (C) a filler; Contains.

[0013] (Component A: Epoxy compound with molecular weight of less than 270 The epoxy resin composition of the present embodiment contains (A) an epoxy compound having a molecular weight of less than 270 (hereinafter, sometimes referred to as component (A)). The epoxy compound (A) has a molecular weight of less than 270, preferably 250 or less, more preferably 230 or less, and even more preferably 210 or less, from the viewpoint of uniformity of the cured product.

[0014] Examples of the epoxy compound (A) having a molecular weight of less than 270 include, but are not limited to, epoxy compounds such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, dicyclopentadiene diepoxide, and dicyclononadiene diepoxide; and bifunctional epoxy resins such as hydroquinone type epoxy resins, methylhydroquinone type epoxy resins, dibutylhydroquinone type epoxy resins, resorcinol type epoxy resins, methylresorcinol type epoxy resins, catechol type epoxy resins, N,N-diglycidylaniline type epoxy resins, and diglycidyl-o-toluidine type epoxy resins.

[0015] Examples of (A) epoxy compounds having a molecular weight of less than 270 include trifunctional epoxy resins such as p-aminophenol type epoxy resins and triazine type epoxy resins.

[0016] Furthermore, examples of (A) epoxy compounds having a molecular weight of less than 270 include monofunctional epoxy compounds such as phenyl glycidyl ether, cresyl glycidyl ether, ps-butylphenyl glycidyl ether, styrene oxide, p-tert-butylphenyl glycidyl ether, o-phenylphenol glycidyl ether, p-phenylphenol glycidyl ether, N-glycidyl phthalimide, n-butyl glycidyl ether, tert-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, α-pinene oxide, allyl glycidyl ether, 1-vinyl-3,4-epoxycyclohexane, 1,2-epoxy-4-(2-methyloxiranyl)-1-methylcyclohexane, and neodecanoic acid glycidyl ester, and include aromatic epoxy compounds, aliphatic epoxy compounds, and alicyclic epoxy compounds that can also be used as reactive diluents.

[0017] As the (A) epoxy compound having a molecular weight of less than 270, from the viewpoint of storage stability, an epoxy compound having an aromatic ring or an alicyclic structure in the structure is preferred.

[0018] (Component B: Solid dispersion type epoxy resin hardener) The epoxy resin composition of the present embodiment contains (B) a solid dispersion-type epoxy resin curing agent (hereinafter, may be referred to as component (B)). (B) The solid dispersion type epoxy resin curing agent is not limited to the following, but examples thereof include amine-based adducts and microcapsule type curing agents obtained by coating these.

[0019] (B) Solid dispersion type epoxy resin curing agents are not limited to the following, but examples of amine adducts include Amicure PN-23, PN-23J, PN-40, PN-40J, PN-H, MY-24, MY-H (manufactured by Ajinomoto Fine-Techno Co., Ltd.), Fujicure FXR-1020, FXR-1030 (manufactured by Fuji Chemical Industry Co., Ltd.), and the like. Examples of microcapsule type curing agents include Novacure HX-3742, HX-3921HP, HXA3932HP, HXA9322HP, HXA3792, HXA9382HP, and LSA-H2204 (manufactured by Asahi Kasei Corporation).

[0020] The (B) solid-dispersed epoxy resin curing agent preferably has an exothermic peak temperature of 100°C or higher and 200°C or lower when a mixture of the (B) solid-dispersed epoxy resin curing agent and a liquid bisphenol A type epoxy resin in a mass ratio of 1:1 is measured by DSC at a heating rate of 2°C / min. When the exothermic peak temperature is within this temperature range, component (B) has good storage stability when mixed with the above-mentioned component (A) and the later-described component (C). The exothermic peak temperature is more preferably 105°C or higher and 190°C or lower, and further preferably 115°C or higher and 180°C or lower. Regarding (B) a solid dispersion type epoxy resin curing agent, the exothermic peak temperature can be measured by the method described in the Examples below, and can be controlled within the above numerical range by microencapsulating the curing agent component with an appropriate thickness and material, although it is not particularly limited.

[0021] (B) The solid dispersion type epoxy resin curing agent is preferably a microcapsule type, which tends to improve storage stability during heating.

[0022] In the epoxy resin composition of the present embodiment, the content of component (B) in the epoxy resin composition excluding the content of component (C) from the epoxy resin composition is preferably 0.1% by mass or more from the viewpoint of curability, and is preferably 40% by mass or less from the viewpoint of storage stability, more preferably 0.2 to 35% by mass, and further preferably 1.0 to 30% by mass.

[0023] (Component C: Filler) The epoxy resin composition of the present embodiment contains a filler (C) (hereinafter, may be referred to as component (C)). (C) The filler includes an organic filler and an inorganic filler.

[0024] The organic filler functions as a shock mitigating agent, capable of mitigating stress caused by impact. By containing an organic filler, the epoxy resin composition of the present embodiment can further improve the adhesion to various connecting members. In addition, the occurrence and progression of fillet cracks tends to be suppressed.

[0025] Examples of the organic filler include, but are not limited to, organic fine particles of acrylic resin, silicone resin, butadiene rubber, polyester, polyurethane, polyvinyl butyral, polyarylate, polymethyl methacrylate, acrylic rubber, polystyrene, NBR, SBR, silicone-modified resin, and copolymers containing these as components. From the viewpoint of improving adhesion, examples of organic fine particles include alkyl (meth)acrylate-butadiene-styrene copolymers, alkyl (meth)acrylate-silicone copolymers, silicone-(meth)acrylic copolymers, complexes of silicone and (meth)acrylic acid, complexes of alkyl (meth)acrylate-butadiene-styrene and silicone, and complexes of alkyl (meth)acrylate and silicone. The organic filler may also be organic fine particles having a core-shell structure with different compositions between the core layer and the shell layer. Examples of the core-shell organic fine particles include particles having a silicone-acrylic rubber core to which an acrylic resin is grafted, and particles having an acrylic resin grafted to an acrylic copolymer. These organic fillers may be used alone or in combination of two or more kinds.

[0026] The inorganic filler has a function of adjusting the thermal expansion coefficient of the epoxy resin composition. When the epoxy resin composition of the present embodiment contains an inorganic filler, it tends to contribute to improving heat resistance, moisture resistance, heat dissipation, and electrical conductivity when used as a sealant or a conductive paste.

[0027] Examples of inorganic fillers include, but are not limited to, silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium oxide, 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; and conductive particles such as gold, silver, nickel, copper, palladium, platinum, bismuth, tin, alloys thereof (particularly, bismuth-tin alloys, solder, etc.), aluminum, indium tin oxide, silver-coated copper, silver-coated aluminum, metal-coated glass spheres, silver-coated fibers, silver-coated resin antimony-doped tin, tin oxide, carbon fibers, graphite, and carbon black. Among these, from the viewpoint of improving heat resistance, moisture resistance, and strength, fused silica, crystalline silica, and synthetic silica powder are preferred, and any of silicon oxide, aluminum oxide, and boron nitride is also preferred. By using these, the coefficient of linear thermal expansion can be suppressed, and improvement in thermal cycle tests, etc. is expected. The shape of the inorganic filler is not particularly limited, and may be, for example, any of amorphous, spherical, and flaky shapes. These inorganic fillers may be used alone or in combination of two or more kinds.

[0028] In the epoxy resin composition of the present embodiment, the mass proportion of the filler (C) is preferably 30 mass % or more and 98 mass % or less. It is more preferably from 40% by mass to 95% by mass, and further preferably from 45% by mass to 90% by mass. When the mass proportion of the (C) filler is 30 mass % or more, it tends to be possible to develop physical properties of the cured product, such as electrical conductivity, heat dissipation, and a low linear expansion coefficient, and when it is 98 mass % or less, the flowability of the epoxy resin composition of the present embodiment tends to be good.

[0029] (Component D Epoxy resin) The epoxy resin composition of the present embodiment may contain component (D) epoxy resin (hereinafter sometimes referred to as component (D)). Examples of the epoxy resin of component (D) include, but are not limited to, bisphenol A type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol M type epoxy resin, bisphenol P 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, phenyl benzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin, diphenyl sulfone type epoxy resin, diphenyl ether ... Examples of such epoxy resins include bifunctional epoxy resins such as phenyl disulfide type epoxy resins, naphthalene type epoxy resins, and anthracene type epoxy resins; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane type epoxy resins and diaminobenzene type epoxy resins; multifunctional 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; and alicyclic epoxy resins. These may be used alone or in combination of two or more thereof. Furthermore, epoxy resins modified with isocyanate or the like may also be used in combination. The epoxy resin of component (D) can be clearly distinguished from the epoxy compound of component (A) described above in that the molecular weight of the epoxy resin is 270 or more.

[0030] From the viewpoints of handleability and heat resistance, the epoxy resin composition of the present embodiment preferably contains a bisphenol-type epoxy resin as the epoxy resin component (D), and preferably contains a bisphenol A-type epoxy resin from the viewpoint of imparting sufficient mechanical properties.

[0031] In the epoxy resin composition of the present embodiment, from the viewpoints of storage stability and uniformity of the cured product, the blending mass ratio of component (A) to component (D) is preferably component (A):component (D)=100:0 to 10:90, more preferably 85:15 to 15:85, and even more preferably 70:30 to 30:70.

[0032] (Component E Epoxy resin hardener) The epoxy resin composition of the present embodiment may contain an epoxy resin curing agent (E) (hereinafter sometimes referred to as component (E)) other than the solid dispersion-type epoxy resin curing agent (C). (E) Epoxy resin curing agents include, but are not limited to, for example, amine-based curing agents, amide-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, active ester-based curing agents, thiol-based curing agents, and catalyst-type curing agents.

[0033] Examples of the amine-based curing agent include, but are not limited to, aliphatic amines and aromatic amines. Examples of aliphatic amines include, but are not limited to, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, bis(4-aminocyclohexyl)methane, norbornenediamine, and 1,2-diaminocyclohexane. Examples of aromatic amines include, but are not limited to, diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, trimethylenebis(4-aminobenzoate), polytetramethylene oxide-di-p-aminobenzoate, KAYAHARD AA (manufactured by Nippon Kayaku Co., Ltd.), and Ethacure 100 (manufactured by Mitsui Chemicals Fine Co., Ltd.).

[0034] Examples of the amide-based curing agent include, but are not limited to, dicyandiamide and its derivatives, such as guanidine-based compounds, or compounds in which an acid anhydride is added to an amine-based compound, and hydrazide-based compounds. Examples of hydrazide compounds include, but are not limited to, succinic acid dihydrazide, adipic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, p-oxybenzoic acid hydrazide, salicylic acid hydrazide, phenylaminopropionic acid hydrazide, and maleic acid dihydrazide. Examples of guanidine compounds include, but are not limited to, dicyandiamide, methyl guanidine, ethyl guanidine, propyl guanidine, butyl guanidine, dimethyl guanidine, trimethyl guanidine, phenyl guanidine, diphenyl guanidine, and toluyl guanidine.

[0035] Examples of the phenol-based curing agent include, but are not limited to, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, cresol aralkyl resin, naphthol aralkyl resin, biphenyl-modified phenol resin, biphenyl-modified phenol aralkyl resin, dicyclopentadiene-modified phenol resin, aminotriazine-modified phenol resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, and allyl acryl phenol resin.

[0036] Examples of acid anhydride 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.

[0037] There are no particular limitations on the active ester curing agent as long as it functions as a curing agent for epoxy resins and has an active ester, but a compound having two or more active ester groups in one molecule is preferred. From the viewpoint of heat resistance and the like, an active ester compound obtained by reacting a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound is more preferred, and an active ester compound obtained by reacting a carboxylic acid compound with one or more compounds selected from a phenol compound, a naphthol compound, and a thiol compound is even more preferred. The active ester compounds constituting the active ester curing agent may be used alone or in combination of two or more kinds. As the active ester compound, the active ester compounds disclosed in JP-A-2004-277460 may be used, and commercially available products may also be used. As commercially available active ester compounds, for example, those containing a dicyclopentadienyl diphenol structure, acetylated phenol novolac, and benzoylated phenol novolac are preferred, and in particular those containing a dicyclopentadienyl diphenol structure are more preferred. As those containing a dicyclopentadienyl diphenol structure, for example, EXB9451, EXB9460, EXB9460S, and HPC-8000-65T (manufactured by DIC Corporation), DC808 (manufactured by Japan Epoxy Resins Corporation) as an acetylated phenol novolac, and YLH1026 (manufactured by Japan Epoxy Resins Corporation) as a benzoylated phenol novolac can be mentioned.

[0038] Examples of 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 tetraki ... (3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, pentaerythritol tripropanethiol, pentaerythritol tetrapropanethiol, 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, (1,3,4,6-tetrakis(3-mercaptopropyl)glycoluril, 1,3,4,6-tetrakis(mercaptoethyl)glycoluril, 1,3,4,6-tetrakis(mercaptomethyl)-3a-methylglycoluril, 1,3,4,6-tetrakis(2-mercaptoethyl)-3a-methylglycoluril, 1,3,4,6-tetrakis(3-mercaptopropyl)-3a-methylglycoluril, 1,3,4,6-tetrakis(mercaptomethyl)-3a,6a-dimethylglycoluril, 1,3,4,6-tetrakis(2-mercaptoethyl)-3 Examples of such glycol uril include a,6a-dimethyl glycol uril, 1,3,4,6-tetrakis(3-mercaptopropyl)-3a,6a-dimethyl glycol uril, 1,3,4,6-tetrakis(mercaptomethyl)-3a,6a-diphenyl glycol uril, 1,3,4,6-tetrakis(2-mercaptoethyl)-3a,6a-diphenyl glycol uril, and 1,3,4,6-tetrakis(3-mercaptopropyl)-3a,6a-diphenyl glycol uril.

[0039] Examples of catalyst type curing agents include, but are not limited to, cationic thermosetting catalysts, BF3-amine complexes, and the like.

[0040] The content of component (E) in the epoxy resin composition of the present embodiment is preferably 1 part by mass or more and 300 parts by mass or less when the total of components (A) and (D) is taken as 100 parts by mass, from the viewpoints of the viscosity of the resin composition, the Tg of the cured product, and the adhesiveness. The amount is more preferably 3 to 250 parts by mass, and further preferably 5 to 200 parts by mass.

[0041] (Other additives) In addition to the above-mentioned components, the epoxy resin composition of the present embodiment may further contain additives such as pigments, dyes, flow control agents, thickeners, release agents, wetting agents, flame retardants, and surfactants, as necessary. These additives may be used alone or in combination of two or more.

[0042] Examples of pigments include, but are not limited to, kaolin, chalk powder, gypsum, antimony trioxide, pentone, aerosol, lithopone, barite, and the like.

[0043] Dyes include, but are not limited to, natural dyes such as dyes derived from plants such as madder and indigo, dyes derived from minerals such as yellow ocher and red clay, synthetic dyes such as alizarin and indigo, and fluorescent dyes.

[0044] Examples of flow control agents include, but are not limited to, organic silane compounds such as silane coupling agents; organic titanium compounds such as titanium tetraisopropoxide and titanium diisopropoxybis(acetylacetonate); and organic zirconium compounds such as zirconium tetra-n-butoxide and zirconium tetraacetylacetonate.

[0045] Examples of thickeners include, but are not limited to, animal-based thickeners such as gelatin; vegetable-based thickeners such as polysaccharides and cellulose; and chemically synthesized thickeners such as polyacrylic thickeners, modified polyacrylic thickeners, polyether thickeners, urethane-modified polyether thickeners, and carboxymethyl cellulose.

[0046] Examples of the release agent include, but are not limited to, fluorine-based release agents, silicone-based release agents, and acrylic release agents made of a copolymer of glycidyl (meth)acrylate and a linear alkyl (meth)acrylate having 16 to 22 carbon atoms.

[0047] Examples of wetting agents include, but are not limited to, unsaturated polyester copolymer wetting agents having acidic groups, such as acrylic polyphosphate esters.

[0048] Examples of flame retardants include, but are not limited to, halogen-based 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.

[0049] Examples of surfactants include, but are not limited to, anionic surfactants such as alkylbenzenesulfonates and alkylpolyoxyethylenesulfates, cationic surfactants such as alkyldimethylammonium salts, amphoteric surfactants such as alkyldimethylamine oxides and alkylcarboxybetaines, and nonionic surfactants such as linear alcohols and fatty acid esters having 25 or more carbon atoms.

[0050] The other additives described above can be used alone or in combination of two or more kinds depending on the desired properties of the epoxy resin composition of this embodiment, and the blending amount thereof can also be appropriately selected.

[0051] [Method for producing epoxy resin composition] The epoxy resin composition of the present embodiment can be produced by mixing and kneading the above-mentioned components. The mixing and kneading method is not particularly limited, but examples thereof include methods using a reactor with stirring blades, a planetary mixer, a kneader, a roll, a homodisper, an extruder, and the like. The mixing and kneading step may be performed 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 proceeds during kneading, and the viscosity tends to increase. On the other hand, if the kneading temperature is too low, below 5°C, the viscosity of the epoxy resin or curing agent increases, making kneading difficult, and moisture in the air adheres to the epoxy resin composition, which vaporizes during curing, tending to generate voids in the cured product.

[0052] [Cured product] By curing the epoxy resin composition of the present embodiment, a cured product is obtained. The curing conditions are not particularly limited, but a method of curing in an oven heated to a constant temperature is preferred. EXAMPLES

[0053] Hereinafter, the present embodiment will be described in detail with reference to specific examples and comparative examples, but the present invention is not limited to these examples and comparative examples.

[0054] First, the methods for measuring and evaluating each physical property will be described below. [Physical properties and characteristics of epoxy resin composition] (DSC exothermic peak temperature of curing agent (B)) Using a DSC7020 (Hitachi High-Tech Science Corporation), the temperature was raised from 25° C. to 250° C. at 2° C. / min, and the temperature at which the highest peak appeared on the observed chart was taken as the exothermic peak temperature. The solid dispersion type epoxy resin curing agent and liquid bisphenol A type epoxy resin (product name: jER828) manufactured by Mitsubishi Chemical Corporation were weighed and mixed in a mass ratio of 1:1, and the DSC measurement was carried out.

[0055] (Cured product uniformity) The epoxy resin compositions of the examples and comparative examples described below were held in an open oven at 150° C. for 1 hour to obtain cured products. The obtained hardened material was cut with a diamond cutter or nippers, polished with sandpaper, and the surface was gold-deposited, after which the polished surface was observed with a SEM at 1000x magnification. The obtained SEM images were binarized, and the area ratio (unit: %) of the filler-free region having a circle-equivalent diameter of 3 μm or more was calculated.

[0056] (Storage stability evaluation) The viscosities of the epoxy resin compositions of the examples and comparative examples described below were measured using an E-type viscometer (25° C.) before and after storage at 40° C. for 3 days or at 60° C. for 1 day. Ratio of viscosity of thermosetting resin composition after storage to viscosity of epoxy resin composition before storage The (viscosity ratio after storage) (=viscosity after storage / viscosity before storage) was calculated to evaluate the storage stability.

[0057] [Constituents of epoxy resin composition] ((A) Epoxy compound) A-1: Cyclohexanedimethanol diglycidyl ether (molecular weight 256) A-2: 1,6-Hexanediol diglycidyl ether (molecular weight 230) A-3: Hydroquinone glycidyl ether (molecular weight 222) A-4: Polyethylene glycol diglycidyl ether (molecular weight 218) A-5: p-tert-butylphenyl glycidyl ether (molecular weight 206) A-6: 1,4-butanediol diglycidyl ether (molecular weight 202) A-7: o-Cresyl glycidyl ether (molecular weight 164) A-8: Phenyl glycidyl ether (molecular weight 150) A-9: tert-butyl glycidyl ether (molecular weight 130)

[0058] ((B) Solid dispersion type epoxy resin hardener) B-1: Microcapsule type hardener manufactured by Asahi Kasei Corporation B-2: Microcapsule type hardener manufactured by Asahi Kasei Corporation B-3: Microcapsule type hardener manufactured by Asahi Kasei Corporation B-4: Non-microcapsule type hardener manufactured by Ajinomoto Fine-Techno Co., Ltd. B-5: Microcapsule type hardener manufactured by Asahi Kasei Corporation

[0059] The DSC exothermic peak temperatures and curing agent particle sizes (D90) of the solid dispersion type epoxy resin curing agents B-1 to B-5 are shown in Table 1 below.

[0060] [Table 1]

[0061] ((C) Filler) C-1: SO-E2 (Admatechs, D50=0.5μm) C-2: SO-E1 (Admatechs, D50=0.3μm) C-3: FB-20R (Denka, D50=19.4μm) C-4: Silver particles (As One, D50 = 0.5 μm)

[0062] ((D) Epoxy resin) D-1 Bisphenol A epoxy resin (molecular weight of main component: 340) D-2 Hydrogenated bisphenol A epoxy resin (main component molecular weight 352)

[0063] ((E) Epoxy resin hardener) E-1 Resok Acid Anhydride HN-2200

[0064] [Examples 1 to 18], [Comparative Examples 1 to 6] The components were weighed out in the proportions shown in Tables 2 to 7 below and mixed using a Thinky Mixer to prepare epoxy resin compositions. The properties and characteristics of the epoxy resin composition were measured and evaluated by the methods described above.

[0065] [Table 2]

[0066] [Table 3]

[0067] [Table 4]

[0068] [Table 5]

[0069] [Table 6]

[0070] [Table 7]

[0071] Examples 1 to 16 and Comparative Examples 1 to 4 are examples in which an acid anhydride was used as the (E) curing agent, and Examples 17, 18, and Comparative Examples 5 and 6 are examples in which no (E) curing agent was added. It was found that in the Examples, the area of ​​the region without filler after curing was reduced compared to the Comparative Examples, and the uniformity of the cured product was improved. FIG. 1 shows a cross-sectional view of the cured product of Comparative Example 3, and FIG. 2 shows a cross-sectional view of the cured product of Example 7. As shown in FIG. 1, in Comparative Example 3, there are many black regions where no filler is present, and as shown in FIG. 2, in Example 7, there are fewer black regions where no filler is present. In addition, when Example 7, Example 8 and Example 9, or Example 17 and Example 18 are compared, it is found that the storage stability is improved by the DSC exothermic peak temperature of the solid-dispersed epoxy resin latent curing agent (B) being 100°C or higher. Comparing Example 7 and Example 8, it was found that the storage stability was improved by microencapsulating the solid dispersion-type epoxy resin latent curing agent (B). Comparing Example 5, Example 7 and Example 6, it was found that the storage stability tends to be improved when the epoxy compound (A) has an aromatic ring. [Industrial Applicability]

[0072] The epoxy resin composition of the present invention has industrial applicability as a sealant for semiconductor elements, an insulating material, a conductive adhesive, and a heat dissipation paste.

Claims

1. (A) an epoxy compound having a molecular weight of less than 270; (B) a solid dispersion type epoxy resin curing agent; (C) a filler; and An epoxy resin composition comprising:

2. (B) the solid dispersion type epoxy resin curing agent; A liquid bisphenol A type epoxy resin; The mixture in a mass ratio of 1:1 has an exothermic peak temperature of 100° C. or more and 200° C. or less when measured by DSC at a heating rate of 2° C. / min. The epoxy resin composition according to claim 1.

3. The (B) solid dispersion type epoxy resin curing agent is a microcapsule type curing agent.

3. The epoxy resin composition according to claim 1 or 2.

4. The mass ratio of the (C) filler is 30% by mass or more and 98% by mass or less, The epoxy resin composition according to claim 1 or 2.

5. The (A) epoxy compound has a molecular weight of 210 or less. The epoxy resin composition according to claim 1 or 2.

6. The epoxy compound (A) has an aromatic ring or an alicyclic structure in its structure. The epoxy resin composition according to claim 1 or 2.

7. The mass ratio of the (C) filler is 30% by mass or more and 98% by mass or less, The epoxy resin composition according to claim 3.

8. The (A) epoxy compound has a molecular weight of 210 or less. The epoxy resin composition according to claim 7.

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