JP2000119369A - Solid epoxy resin, epoxy resin composition and cured product thereof - Google Patents

Abstract

(57) [Abstract] [Problem] With excellent solid handling properties,
It is to provide a crystalline epoxy resin which is solid at room temperature and shows good low viscosity in a molten state, and further has excellent blocking resistance, and is excellent in moldability such as rapid curability, fluidity, and mechanical properties. Provided is an epoxy resin composition excellent in strength, heat resistance, low moisture absorption, high adhesion, and crack resistance, and a cured product thereof. A solid epoxy resin obtained by subjecting a liquid epoxy resin or an epoxy resin-containing solution produced by epoxidizing 2,7-naphthalene diol with epichlorohydrin to a crystallization treatment, and having a melting point peak temperature of 50%.
25 ° C. when the particle size is not less than 5 ° C. and not more than 5 mm
A solid epoxy resin having a blocking ratio of 20% or less after standing for 24 hours. An epoxy resin composition comprising an epoxy resin, a curing agent and an inorganic filler, wherein the epoxy resin composition contains the epoxy resin as an epoxy resin component in an amount of 10% by weight or more and further contains an inorganic filler in an amount of 75% by weight or more. And a cured product obtained by curing the epoxy resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystalline epoxy resin excellent in handleability as a solid at room temperature, an epoxy resin composition containing the same, and a cured product obtained therefrom. It is preferably used for

[0002]

2. Description of the Related Art A resin composition containing an epoxy resin as a main material is widely used in electric and electronic fields such as casting, sealing, and laminates. In recent years, due to miniaturization and thinning of electronic components, epoxy resin compositions having lower viscosity have been desired.
Conventional epoxy resin compositions often have relatively high viscosity, so that the resin does not completely flow into minute gaps between parts or causes molding defects such as entrapment of bubbles,
There are problems such as poor insulation and deterioration of moisture resistance.

In particular, in the field of semiconductors, as a method of mounting components on a printed circuit board, a shift from a conventional pin insertion method to a surface mounting method is progressing. In the surface mounting method, the entire package is heated to the solder temperature, and package cracks due to thermal shock have become a major problem. Furthermore, in recent years, high integration of semiconductor devices, enlargement of device size, and miniaturization of wiring width are also rapidly progressing, and the problem of package cracking is becoming more serious. As methods for preventing package cracks, there are methods such as toughening of the resin structure, high strength due to high filling of silica, and low water absorption.

[0004] In order to overcome the above problems, an epoxy resin excellent in low viscosity has been desired. As the low-viscosity epoxy resin, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin and the like are generally and widely used. However, among these epoxy resins, those having low viscosity are liquid at room temperature and are difficult to handle. Furthermore, these epoxy resins are not sufficient in heat resistance, mechanical strength, and toughness.

In view of the above background, many epoxy resin compositions using a crystalline epoxy resin that is solid at room temperature have recently been proposed. Japanese Patent Publication No. 4-7365 proposes an epoxy resin composition for semiconductor encapsulation containing a biphenyl-based epoxy resin as a main component as an improvement in handling workability, heat resistance, toughness and the like. , Low viscosity and curability are not sufficient. Also, Japanese Patent Application Laid-Open No. 6-345
No. 850 proposes a bisphenol F type solid epoxy resin as a main ingredient. Bisphenol F type epoxy resins have excellent low viscosity properties, but have problems in heat resistance and curability.

Japanese Unexamined Patent Publication (Kokai) No. 61-73719 proposes a diglycidyl ether compound of naphthalene diols for improving heat resistance, moisture resistance and low viscosity. As a specific application example, Japanese Patent Application Laid-Open No. 2-8862
No. 1 proposes an epoxy resin composition for semiconductor encapsulation using a 1,6-naphthalenediol diglycidyl ether compound. This is characterized by excellent heat resistance and moisture resistance and excellent curability due to the condensed polycyclic aromatic structure of naphthalene. Although it is excellent in low viscosity, 1,6-naphthalenediol diglycidyl ether compound hardly takes a crystal structure due to its asymmetric structure, and gives a viscous resin at normal temperature.
Therefore, there is a problem that the handleability as a solid is inferior and the blocking resistance of the epoxy resin composition is reduced.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a crystalline epoxy resin which is excellent in handleability in a solid state and which exhibits good low viscosity in a molten state and which is solid at room temperature. An epoxy resin composition having excellent blocking resistance, rapid curability, excellent moldability such as fluidity, and excellent mechanical strength, heat resistance, low moisture absorption, high adhesion, and crack resistance. It is to provide a cured product.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above problems, and as a result, among various naphthalene diol-based epoxy resins, a crystallized product of a specific isomer of 2,7-disubstitution is obtained. That it has good handling properties at normal temperature, excellent melting property at molding temperature, and good low viscosity at the time of melting, and that the epoxy resin composition containing this has excellent cured physical properties. And find
The present invention has been reached.

That is, the present invention relates to a solid epoxy resin obtained by subjecting a liquid epoxy resin or an epoxy resin-containing solution produced by epoxidizing 2,7-naphthalene diol with epichlorohydrin to a crystallization treatment, and having a melting point of A solid epoxy resin having a peak temperature of 50 ° C. or more and a blocking rate of 20% or less after standing at 25 ° C. for 24 hours when the particle size is 5 mm or less. An epoxy resin composition comprising an epoxy resin, a curing agent, and an inorganic filler, wherein the epoxy resin contains the epoxy resin in an amount of 10% by weight or more of the total epoxy resin component, and further contains an inorganic filler in an amount of 75% by weight or more. A composition. Further, it is a cured product obtained by curing the epoxy resin composition.

The naphthalene diol epoxy resin used in the present invention is a crystallized 2,7-disubstituted product. On the other hand, for example, 1,6-disubstituted compounds having an asymmetric structure, 1,7
-The di-substituted product is a viscous resinous material at normal temperature, is inferior in solid handling properties, and is inferior in heat resistance of a cured product due to an asymmetric structure. In addition, 2,6 with excellent symmetry
The di-substituted product and the 1,5-di-substituted product have a high melting point of 150 ° C. or higher, and have excellent handling properties as a solid of the epoxy resin, but a curing agent for preparing the epoxy resin composition, Poor compatibility and miscibility with additives and the like.

The epoxy resin of the present invention is produced by reacting 2,7-naphthalene diol with epichlorohydrin. This reaction can be performed in the same manner as a usual epoxidation reaction. For example, after dissolving 2,7-naphthalenediol in excess epichlorohydrin,
In the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, at 50 to 150 ° C, preferably 60 to 150 ° C.
A method of reacting at 100 ° C. for 1 to 10 hours is exemplified.
At this time, the amount of the alkali metal hydroxide used is 0.8 to 1. 1 mol per mol of the hydroxyl group in 2,7-naphthalene diol.
It is 2 mol, preferably 0.9 to 1.0 mol. If the amount is less than this, the amount of remaining hydrolyzable chlorine increases, and if it is more than this, the amount of gelation increases, the amount of emulsion formed during washing increases, and the yield decreases. The amount of epichlorohydrin used is usually
3 to 30 of the amount of hydroxyl groups in 2,7-naphthalene diol
Times, preferably 4 to 15 times. If less than this,
The production amount of a high molecular weight product of a dimer or more increases, the viscosity of the epoxy resin increases, and the crystallinity of the epoxy resin decreases due to a decrease in melting point, and the handling properties as a solid deteriorate.

After completion of the reaction, excess epichlorohydrin is distilled off, the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and finally the solvent is distilled off. Thus, the desired epoxy resin can be obtained. Washing with water is repeated as necessary. Usually, the amount of remaining ions such as remaining sodium ions and chlorine ions is 30 ppm or less, preferably 1 ppm or less.
The process is performed until the concentration becomes 0 ppm or less.

The obtained epoxy resin can be further subjected to a purification reaction, if necessary, in order to reduce the amount of remaining hydrolyzable chlorine. The purification reaction is usually performed by dissolving a crude epoxy resin in a solvent such as toluene or methyl isobutyl ketone, and then, in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, at 50 to 150 ° C.
Preferably, the reaction is carried out at 60 to 100 ° C for 1 to 10 hours. Usually, the amount of the alkali metal hydroxide used is 1 to 20 times, preferably 1.5 to 10 times, the amount of hydrolyzable chlorine remaining in the crude epoxy resin.

The epoxy resin thus obtained is
If it contains a liquid or solvent, it is in the form of a solution and is left at room temperature for a long period of time, or when the solvent is removed and left, crystals gradually precipitate, but it is difficult to obtain a solid epoxy resin that does not easily cause blocking. is there. In order to improve the crystallinity and the blocking resistance, the content of the 2,7-naphthalenediglycidyl ether monomer in the epoxy resin is preferably at least 80%, more preferably at least 90%.

The obtained liquid or solution epoxy resin is
It is crystallized and solidified. As a method of the crystallization treatment, a conventionally known method can be employed.For example, a recrystallization method using a solvent may be used, but there is a problem such as a decrease in yield in addition to the necessity of drying the solvent. Is preferred. A method of crystallization by cooling to below the melting point may be used, but in general, simple cooling alone results in a supercooled state, and it is difficult to rapidly crystallize. Industrially, a method of crystallizing while applying shear at a temperature lower than the melting point of the epoxy resin is preferable. To apply shear, for example, a kneader, a mixer, a roll, an extruder, or the like can be used. The temperature for crystallization is usually a temperature 20 to 70 ° C. lower than the melting point of the epoxy resin. Also,
If necessary, a temperature gradient can be provided according to the progress of crystallization. Further, a seed crystal or an appropriate amount of a solvent may be added for the purpose of promoting crystallization.

Further, the solid epoxy resin of the present invention is characterized in that the handleability as a solid at normal temperature is improved. Specifically, when the particle size is 5 mm or less,
It is necessary that the blocking ratio after standing at 5 ° C. for 24 hours is 20% or less. If it exceeds 20%, dry blending becomes difficult, and it becomes difficult to use the obtained epoxy resin composition. Here, the blocking ratio is a value obtained by the following operation. That is, 5mm on 1mm sieve
50 g of the particles under the sieve were placed in a 100 cc beaker, left in a desiccator adjusted to 25 ° C. for 24 hours, and then sieved with a 5 mm sieve.
It is the weight ratio of the amount on the sieve after reciprocating horizontally for 5 minutes at a speed of 2 reciprocations (4 cm) / sec.

The peak temperature of the melting point of the epoxy resin of the present invention is 50 ° C. or higher, preferably 60 ° C. or higher.
If it is lower than this, there is a problem of blocking, and the handling property is reduced. Here, the peak temperature of the melting point is a peak value of an endothermic curve obtained at a heating rate of 5 ° C./min by a differential thermal analyzer. In some cases, two or more melting point peak temperatures may be observed. In this case, the melting point peak temperature is the peak temperature at the peak having the largest endothermic amount.

The purity of the epoxy resin of the present invention, especially the amount of hydrolyzable chlorine, is preferably smaller than the viewpoint of improving the reliability of the electronic parts to be sealed. Although not particularly limited, it is preferably 1000 ppm or less, more preferably 500 ppm or less. In addition, the hydrolyzable chlorine referred to in the present invention refers to a value measured by the following method. That is, after dissolving 0.5 g of a sample in 30 ml of dioxane, 1N-KOH,
10 ml was added, and the mixture was boiled under reflux for 30 minutes.
This is a value obtained by performing potentiometric titration with a 2N-AgNO ₃ aqueous solution.

In the epoxy resin composition of the present invention, the content of the epoxy resin derived from 2,7-naphthalene diol of the present invention is at least 10% by weight, preferably 40% by weight, of all epoxy resin components. That is all. If the amount is less than this, the effects such as excellent heat resistance, moisture resistance, and adhesion due to the 2,7-disubstituted structure are reduced, and a cured product excellent in crack resistance cannot be obtained. In addition to this, the effect of decreasing the viscosity is small, and the filling rate of the inorganic filler cannot be increased.

In the epoxy resin composition of the present invention, in addition to the epoxy resin of the present invention used as an essential component, a general epoxy resin having two or more epoxy groups in a molecule may be used in combination. Examples of such an epoxy resin include divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, and tris- (4 Trihydric or higher phenols such as -hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak and o-cresol novolak, or halogenated bisphenols such as tetrabromobisphenol A And glycidyl ether compounds derived therefrom. These epoxy resins may be used alone or as a mixture of two or more.

The phenolic curing agent used in the epoxy resin composition of the present invention is appropriately selected from those containing two or more phenolic hydroxyl groups in one molecule. For example, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4 ′
Diphenols such as -biphenol, 2,2'-biphenol, hydroquinone, resorcin, catechol, and naphthalene diol, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxy Phenyl) ethane, phenol novolak, o
-Trivalent or more phenols represented by cresol novolak, naphthol novolak, polyvinylphenol, etc., phenols, naphthols or bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2 ' −
Dihydric phenols such as biphenol, hydroquinone, resorcin, catechol, naphthalene diol and the like, formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-xylylene glycol, p-xylylene glycol dimethyl ether, divinylbenzene, diisopropenylbenzene And polymethoxyphenolic compounds synthesized by reaction with a crosslinking agent such as dimethoxymethylbiphenyls, divinylbiphenyl and diisopropenylbiphenyls.
These curing agents may be used alone or in combination of two or more.

The softening point of the phenolic curing agent is preferably from 40 to 150 ° C, more preferably from 50 to 120 ° C. If it is lower than this, there is a problem of blocking during storage, and if it is higher than this, there is a problem in kneadability and moldability in preparing the epoxy resin composition. The melt viscosity at 150 ° C. is preferably 20 poise or less, more preferably 5 poise or less. If it is higher than this, there is a problem in kneadability and moldability in preparing the epoxy resin composition.

The inorganic filler used in the epoxy resin composition of the present invention includes, for example, silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, fosterite,
Powders such as steatite, spinel, mullite, titania, or spherical beads thereof;
More than one type can be used. In particular, spherical fused silica is preferably used from the viewpoint of high filling of the inorganic filler. Usually, silica is used in combination with one having several types of particle size distribution. The average particle size of the combined silica is from 0.5 to 100 μm. The compounding amount of the inorganic filler is 75% by weight or more, preferably 80% by weight or more, more preferably 84% by weight or more. If this is less than 75% by weight, the effect of improving the solder heat resistance is small.

The epoxy resin composition of the present invention may contain conventionally known curing accelerators such as amines, imidazoles, organic phosphines, Lewis acids and the like. Specifically, 1,8-diazabicyclo (5,
4,0) undenecene-7, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, 2-methylimidazole,
Imidazoles such as 2-phenylimidazole, 2-phenyl-4-methylimidazole and 2-heptadecylimidazole; organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine and phenylphosphine; tetraphenyl Phosphonium tetraphenylborate,
Tetra-substituted phosphonium / tetra-substituted borate such as tetraphenylphosphonium / ethyltriphenylborate, tetrabutylphosphonium / tetrabutylborate,
Examples thereof include tetraphenylboron salts such as 2-ethyl-4-methylimidazole / tetraphenylborate and N-methylmorpholine / tetraphenylborate. The amount is usually 0.2 to 10 parts by weight based on 100 parts by weight of the epoxy resin.

Further, the epoxy resin composition of the present invention comprises:
Thermoplastic oligomers can be blended from the viewpoint of improving fluidity during molding and improving adhesion to a lead frame or the like. Examples of thermoplastic oligomers include C
₅ system and C ₉ based petroleum resins, styrene resins, indene resins, indene-styrene copolymer resin, indene-styrene-phenol copolymer resin, indene-coumarone copolymer resins, indene-benzothiophene copolymer resins . The compounding amount is usually 100
It is 2 to 30 parts by weight based on parts by weight.

If necessary, the epoxy resin composition of the present invention may contain a flame retardant such as brominated epoxy, a mold release agent such as carnauba wax or ester wax, epoxy silane, amino silane, ureido silane, vinyl silane, alkyl silane, or the like. Coupling agents such as silane, organic titanate and aluminum alcoholate; coloring agents such as carbon black; flame retardant aids such as antimony trioxide; low stress agents such as silicone oil; lubricants such as higher fatty acids and higher fatty acid metal salts. And the like.

In general, a molding material can be prepared by sufficiently mixing a predetermined amount of the above-mentioned raw materials with a mixer or the like, kneading with a mixing roll, an extruder, or the like, cooling and pulverizing. .

As a method of sealing an electronic component using the molding material thus prepared, a low-pressure transfer molding method is the most common, but an injection molding method or a compression molding method is also possible.

[0029]

EXAMPLE 1 160 g of 2,7-naphthalenediol was dissolved in 1400 g of epichlorohydrin, and the solution was concentrated under reduced pressure (about 150 mmHg).
At 0 ° C., 163.5 g of a 48% aqueous sodium hydroxide solution
It was dropped over time. During this time, the generated water was removed from the system by azeotropic distillation with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After completion of the dropwise addition, the reaction was continued for another hour. Thereafter, salts produced by filtration were removed, and after further washing with water, epichlorohydrin was distilled off.
250.2 g of a green-yellow viscous crude epoxy resin was obtained. The epoxy equivalent of this epoxy resin is 153,
Hydrolysable chlorine was 3600 ppm. 200 g of the obtained epoxy resin was dissolved in 400 ml of methyl isobutyl ketone, 24.4 g of a 10% aqueous sodium hydroxide solution was added, and the mixture was reacted at 80 ° C. for 2 hours. After the reaction, the reaction mixture was filtered and washed with water, and the solvent, methyl isobutyl ketone, was distilled off under reduced pressure to obtain 196.1 g of a green-yellow viscous resin.

The obtained viscous epoxy resin was cooled in a kneader to 30 ° C. or lower and crystallized by applying shear to obtain a crystalline solid epoxy resin. The peak temperatures of the melting points of the obtained crystals were 64.1 ° C. and 70.6 ° C. The epoxy equivalent of the obtained epoxy resin is 141,
The hydrolyzable chlorine was 180 ppm. The content of the diglycidyl compound monomer of 2,7-naphthalenediol in GPC was 92%. Here, the GPC measurement is
Apparatus: HLC-82A (manufactured by Tosoh) and column: TSK
-GEL2000x3 and TSK-GEL4000x
Using one (all made by Tosoh), solvent: tetrahydrofuran, flow rate: 1.0 ml / min, temperature: 38 ° C, detector:
Performed under the conditions of RI. The melt viscosity at 150 ° C. was 0.075 poise. Here, the melt viscosity was measured using a Reomat 115 manufactured by Contrabass.

The handling property of the solid was evaluated by a blocking rate. That is, the obtained crystalline epoxy resin was pulverized to a particle size of 5 mm or less, 50 g of particles under a 5 mm sieve on a 1 mm sieve were put in a 100 cc beaker, and left in a desiccator adjusted to 25 ° C. for 24 hours. The weight ratio of the amount on the sieve after horizontally reciprocating with a 5 mm sieve at a speed of 2 reciprocations (4 cm) / sec for 5 minutes. The compatibility with the curing agent is
150 ° C. using phenol novolak as a curing agent
And melt-mixing was performed, and the degree was evaluated. The results are summarized in Table 1.

Reference Examples 1 to 4 Instead of 2,7-naphthalene diol, 1,6-naphthalene diol, 1,7-naphthalene diol, 1,5
An epoxidation reaction was carried out in the same manner as in Example 1 except that -naphthalene diol and 2,6-naphthalene diol were used. Example 1 about the obtained epoxy resin
Table 1 shows the results of the evaluation in the same manner as in the above.

Examples 2-3 and Comparative Examples 1-4 As the epoxy resin components, the epoxy resins obtained in Example 1 and Reference Examples 1-2 and biphenyl-based epoxy resins (epoxy resin A: made of Yuka Shell Epoxy, YX4000H
K: epoxy equivalent 195, hydrolyzable chlorine 450 ppm,
Melting point 105 ° C.) and o-cresol-novolak type epoxy resin (epoxy resin B: Nippon Kayaku, EOCN-1)
020-65; epoxy equivalent 200, hydrolyzable chlorine 4
Phenol novolak (curing agent A: manufactured by Gunei Chemical Co., PSM-4261).
OH equivalent: 103, softening point: 82 ° C.), phenol aralkyl type resin (curing agent B: manufactured by Mitsui Chemicals, XL-225-L)
L: OH equivalent: 174, softening point: 75 ° C.) and a novolak type brominated epoxy resin (brominated epoxy A: Nippon Kayaku, BREN-S; epoxy equivalent: 2) as a flame retardant
84, hydrolyzable chlorine 600 ppm, softening point 84 ° C.), spherical silica (average particle size, 16 μm) as a filler, triphenylphosphine as a curing accelerator, γ-aminopropyltriethoxysilane as a silane coupling agent, and others Using the additives shown in Table 2 below, the components were blended at the ratio shown in Table 2 and then kneaded to prepare an epoxy resin composition.
This epoxy resin composition was molded at 175 ° C.
After post-curing at 75 ° C. for 12 hours to obtain a cured product test piece, it was subjected to various physical property measurements.

The glass transition point was determined by a thermomechanical measuring device at a temperature rising rate of 10 ° C./min. The flexural strength and flexural modulus were determined by a three-point bending method. Adhesive strength was determined at 175 ° C using a compression molding machine at a temperature of 175 ° C.
After 12 hours of post-curing, evaluation was made by determining the tensile shear strength. The water absorption was determined by molding a disk having a diameter of 50 mm and a thickness of 3 mm using this epoxy resin composition, and post-curing it at 85 ° C. and 85% R.C. H. The weight change rate after moisture absorption for 24 hours and 100 hours under the above conditions was obtained.
The crack occurrence rate was QFP-80 pin (14 ×
20 × 2.5mm), post-cure, 85 ℃,
85% R. H. After absorbing moisture for a predetermined time under the conditions described above, the package was immersed in a solder bath at 260 ° C. for 10 seconds, and the state of the package was observed and determined. The blocking resistance was defined as the weight ratio of the agglomerated portion after leaving the epoxy resin composition pulverized to a particle size of 2 mm or less at 25 ° C. for 24 hours. Table 3 summarizes the results.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

The epoxy resin of the present invention is excellent in handleability in a solid state and shows good low viscosity in a molten state. In addition, the epoxy resin composition obtained from the epoxy resin of the present invention has excellent moldability such as rapid curability and fluidity, has good blocking resistance as a composition, and has mechanical strength and heat resistance. When a cured product with excellent low moisture absorption, high adhesion, and crack resistance is given and applied to encapsulation of electronic components such as semiconductor devices, crack resistance is greatly improved and excellent solder heat resistance is exhibited. .

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Claims (3)

[Claims] 1. A solid epoxy resin obtained by subjecting a liquid epoxy resin or a solution containing an epoxy resin produced by epoxidizing 2,7-naphthalene diol with epichlorohydrin to a crystallization treatment, and having a peak melting point temperature of 50.
25 ° C. when the particle size is not less than 5 ° C. and not more than 5 mm
A solid epoxy resin having a blocking ratio of 20% or less after standing for 24 hours. 2. An epoxy resin composition comprising an epoxy resin, a phenolic curing agent and an inorganic filler, wherein the solid epoxy resin of claim 1 is contained as an epoxy resin component in an amount of at least 10% by weight of the total epoxy resin component, and An epoxy resin composition containing 75% by weight or more of a filler. 3. A cured product obtained by curing the epoxy resin composition according to claim 2.