JPH1053638A - Epoxy resin, epoxy resin composition and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin, capable of manifesting performances such as a low expansion, a low hygroscopicity and a high strength and useful as a semiconductor sealing material of high reliability by specifying the relationship between the melt viscosity and the content of tri- to hexanuclear skeletal substances. SOLUTION: This epoxy resin is represented by formula I [R is H or a 1-5C alkyl; (n) is an average value and a positive integer of 0.1-20] and has a plot of the melt viscosity [(y): P] obtained by measurement at 150 deg.C by using a cone-plate method versus the content of the total weight of tri- to hexanuclear skeletal substances [(x): wt.%] present in a region surrounded by formulae II and III, (x) = 10 and (x) = 70. The resin is preferably obtained by polycondensing, e.g. phenol with formaldehyde in the presence of an acidic catalyst, carrying out the column treatment or thermal distillation, etc., of the resultant phenolic novolak resin under a high vacuum, removing components other than the tri- to hexanuclear skeletal substances and then reacting the obtained phenolic novolak resin with epihalohydrins.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating material for electric and electronic parts such as a high-reliability semiconductor encapsulation, and various kinds of materials such as a laminate (printed wiring board) and CFRP (carbon fiber reinforced plastic). The present invention relates to an epoxy resin, an epoxy resin composition, and a cured product thereof useful for a material for a composite material, an adhesive, a paint, and the like.

[0002]

2. Description of the Related Art Epoxy resins are used in the fields of electric and electronic parts, structural materials, adhesives, paints, etc. due to workability and excellent electrical properties, heat resistance, adhesiveness, moisture resistance (water resistance), etc. of the cured product. Widely used in

[0003]

However, in recent years, with the development in the electric and electronic fields, epoxy resins have been improved in heat resistance, moisture resistance, adhesion, and low viscosity for high filling of fillers. There is a demand for further improvements in various properties such as. In addition, as a structural material, an epoxy resin that is lightweight and has excellent mechanical properties in aerospace materials, leisure and sports equipment applications, and the like, and at the same time, a low-viscosity epoxy resin is required to improve workability. Many proposals have been made for epoxy resin compositions to meet these requirements, but they have not been satisfactory yet.

[0004]

Means for Solving the Problems The present inventors have made intensive studies on epoxy resins having the above-mentioned characteristics, and have completed the present invention.

That is, the present invention provides: (1) the following formula (I)

[0006]

Embedded image

Wherein R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and n is a positive number having an average value of 0.1 to 20. The plot of the melt viscosity at 150 ° C. (y; poise) versus the ratio of the total weight of the 3 to 6 nuclei in the epoxy resin (x; wt%) ^{measured in} 1) is as follows: 1) y = 60e ^−0.115X , 2 ) Y = 1000
e- ^0.115X , 3) x = 10, 4) epoxy resin present in the area surrounded by the line of x = 70, (2) plot of y vs. x: 1) y = 70e- ^0.115X , 2) y = 1000
e- ^0.115X , 3) x = 10, 4) the epoxy resin according to the above (1), which is present in a region surrounded by a line of x = 70, (3) a top peak in GPC (gel permeation chromatography). The epoxy resin according to the above (1) or (2), wherein the epoxy resin component contained in the constituting fraction is a trinuclear or higher nucleus; (4) The epoxy resin according to the above (1) having a melt viscosity of 0.1 poise to 400 poise. ), The epoxy resin according to any one of (2) and (3), (5) the epoxy resin according to any one of (1), (2), (3) and (4) above. (6) the epoxy resin composition according to the above (5) prepared for semiconductor encapsulation, (7) the epoxy resin composition according to the above (5) or (6), which is cured. Cured product.

In the epoxy resin described in the above (1), m
The nucleus (m represents an integer) refers to a molecule in the epoxy resin represented by the formula (I) in which m aromatic rings are contained in one molecule (the same applies hereinafter). In the following phenol novolak resin, the w nucleus (w represents an integer) refers to a molecule in a phenol novolak resin in which one molecule contains w aromatic rings (the same applies hereinafter).

The epoxy resin of the present invention has a melt viscosity at 150 ° C. (y; poise) measured by a cone-plate method and a percentage (x;
Weight%) plots: 1) y = 60e- ^0.115X , 2)
y = 1000e- ^0.115X , 3) x = 10, 4) x = 70
(Refer to FIG. 1), preferably 1) y = 70e ^−0.115X , 2) y = 1000e
^-0.115X , 3) x = 10, 4) exists in the area surrounded by the line of x = 70.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The epoxy resin of the present invention can be prepared by subjecting a phenol novolak resin obtained by, for example, condensation polymerization of phenol and formaldehyde with an acid catalyst to 3 to 6 by column treatment or heat distillation under high vacuum. It can be obtained by reacting a phenol novolak resin obtained by removing components other than the core with epihalohydrins.

Specific examples of epihalohydrins that can be used in this epoxidation reaction include epichlorohydrin, β-
Methyl epichlorohydrin, epibromohydrin, β-
Methyl epibromhydrin, epiiodohydrin, β-
Ethyl epichlorohydrin and the like can be mentioned, but epichlorohydrin which is easily available industrially and is inexpensive is preferable. This epoxidation reaction can be performed according to a conventionally known method.

For example, a solid of alkali metal hydroxide such as sodium hydroxide, potassium hydroxide or the like is added to the mixture of the phenol novolak resin and the epihalohydrin at once at a temperature of 20 to 120 ° C. Let react for ~ 10 hours. At this time, the alkali metal hydroxide may be used in the form of an aqueous solution.In this case, the alkali metal hydroxide is continuously added, and water and water are continuously added to the reaction mixture under reduced pressure or normal pressure. A method may be employed in which epihalohydrins are distilled off, the liquid is further separated to remove water, and the epihalohydrins are continuously returned to the reaction mixture.

In the above method, the amount of the epihalohydrin used is usually 0.5 to 20 mol, preferably 0.7 to 10 mol per equivalent of the hydroxyl group of the phenol novolak resin.
Is a mole. The amount of the alkali metal hydroxide used is usually 0.5 to 1 equivalent of the hydroxyl group in the phenol novolak resin.
To 1.5 mol, preferably 0.7 to 1.2 mol.
Further, by adding an aprotic polar solvent such as dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, 1,3-dimethyl-2-imidazolidinone, an epoxy resin having a low hydrolyzable halogen concentration defined below can be obtained. This epoxy resin is suitable for use in sealing electronic materials. The amount of the aprotic polar solvent used is usually 5 to 200% by weight, preferably 10 to 100% by weight, based on the weight of the epihalohydrin. In addition to the above solvents, addition of alcohols such as methanol and ethanol, and cyclic and chain ethers such as 1,4-dioxane facilitates the reaction. The concentration of the hydrolyzable halogen and the aprotic polar solvent are also increased. Is higher than when these solvents are used, but lower than when these solvents are not used. Further, toluene, xylene and the like can be used. Here, the hydrolyzable halogen concentration can be measured, for example, by placing an epoxy resin in a dioxane and 1N-KOH / ethanol solution, refluxing for several tens minutes, and then titrating with a silver nitrate solution.

Further, a mixture of a phenol novolak resin and an excess of epihalohydrins is added to tetramethylammonium chloride, tetramethylammonium bromide,
Using a quaternary ammonium salt such as trimethylbenzylammonium chloride as a catalyst,
And a solid or aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to the resulting phenol novolak resin halohydrin ether, and the mixture is reacted at 20 to 120 ° C. for 1 to 10 hours. Then, the epoxy resin of the present invention can be obtained by ring closure of the halohydrin ether. In this case, the amount of the quaternary ammonium salt used is usually 0.001 to 0.2 mol, preferably 0.05 to 0.1 mol, per 1 equivalent of the hydroxyl group of the phenol novolak resin. The amount of the alkali metal hydroxide to be used is generally 0.8 to 1.5 mol, preferably 0.9 to 1 mol, per 1 equivalent of the hydroxyl group of the phenol novolak resin.
1 mole.

Usually, these reaction products are dissolved in a solvent such as toluene, methyl isobutyl ketone, methyl ethyl ketone after washing with or without water to remove excess epihalohydrins and other solvents used under heating and reduced pressure. Then, by adding an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide and reacting again, an epoxy resin having a low hydrolyzable halogen concentration can be obtained. In this case, the amount of the alkali metal hydroxide to be used is usually 0.01 to 0.2 mol, preferably 0.05 to 0.2 mol per equivalent of the hydroxyl group of the phenol novolak resin.
0.1 mol. The reaction temperature is usually 50 to 120 ° C, and the reaction time is usually 0.5 to 2 hours. After the reaction is completed, salts produced as by-products are removed by filtration, washing with water, etc., and the solvent such as toluene, methyl isobutyl ketone and methyl ethyl ketone is distilled off under reduced pressure under heating to obtain the epoxy resin of the present invention having a low hydrolyzable halogen concentration. be able to.

The epoxy resin of the present invention thus obtained preferably has a trinuclear or higher epoxy resin component in the fraction constituting the top peak in GPC (gel permeation chromatography). Further, the melt viscosity at 150 ° C. measured by the cone plate method is preferably 0.1 poise to 400 poise.

Hereinafter, the epoxy resin composition of the present invention will be described.

In the epoxy resin composition described in the above (5), the epoxy resin of the present invention can be used alone or in combination with another epoxy resin. When used together,
The proportion of the epoxy resin of the present invention in the total epoxy resin is preferably at least 30% by weight, particularly preferably at least 40% by weight.

Specific examples of other epoxy resins that can be used in combination with the epoxy resin of the present invention include bisphenols, phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes. With phenols and various diene compounds, polycondensates with phenols and aromatic dimethylol,
Glycidyl ether-based epoxy resins obtained by glycidylation of biphenols, alcohols, etc., alicyclic epoxy resins, glycidylamine-based epoxy resins, glycidyl ester-based epoxy resins, and the like are included. It is not something to be done. These epoxy resins may be used alone or in combination of two or more.

[0020] In a preferred embodiment of the epoxy resin composition of the present invention, a curing agent is contained. As the curing agent, amine compounds, acid anhydride compounds, amide compounds, phenol compounds and the like can be used. Specific examples of the curing agent that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine, phthalic anhydride, and trianhydride. Melitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride,
Polycondensates of methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, bisphenols, phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes , Polymers of phenols and various diene compounds, polycondensates of phenols and aromatic dimethylol,
Biphenols and modified products thereof, imidazole, B
F ₃ - amine complex, guanidine derivatives. The content of the curing agent is preferably 0.5 to 1.5 equivalents, more preferably 0.6 to 1.5 equivalents to 1 equivalent of epoxy group of the epoxy resin.
1.2 equivalents are particularly preferred. If the amount is less than 0.5 equivalents or more than 1.5 equivalents with respect to 1 equivalent of the epoxy group, curing may be incomplete and good cured physical properties may not be obtained.

When the above curing agent is used, a curing accelerator may be used in combination. Specific examples of the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, and 1,8-diaza. Tertiary amines such as -bicyclo (5,4,0) undecene-7; phosphines such as triphenylphosphine; and metal compounds such as tin octylate. The curing accelerator is contained, if necessary, in an amount of 0.01 to 15 parts by weight based on 100 parts by weight of the epoxy resin.

Further, the epoxy resin composition of the present invention may contain various compounding agents such as a filler such as silica, alumina and talc, a silane coupling agent, a release agent and a pigment, if necessary. it can.

The epoxy resin composition of the present invention is obtained by uniformly mixing the above components at a predetermined ratio, and is preferably used for semiconductor encapsulation. The epoxy resin composition of the present invention can be easily made into a cured product by a method similar to a conventionally known method. For example, the epoxy resin of the present invention, a curing agent, and, if necessary, a curing accelerator, a filler, and a compounding agent, if necessary, are sufficiently mixed until uniform using an extruder, a kneader, a roll, or the like, and the present invention The epoxy resin composition of the present invention is obtained by molding the epoxy resin composition by a melt casting method or a transfer molding method, an injection molding method, a compression molding method, or the like, and by heating at 80 to 200 ° C. if necessary. A cured product can be obtained.

Further, the epoxy resin composition of the present invention is dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone and the like.
A prepreg obtained by impregnating a substrate such as carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper and drying by heating may be subjected to hot press molding to obtain the cured product of the present invention.

In this case, the proportion of the solvent to the total weight of the epoxy resin composition of the present invention and the solvent is usually 10%.
７０70% by weight, preferably 15-65% by weight.

[0026]

The present invention will be described in more detail with reference to the following examples. Note that the present invention is not limited to these examples. In Examples, the ratio (x;% by weight) of the total weight of 3 to 6 nuclei in the epoxy resin, epoxy equivalent, IC
I viscosity (y) and softening point were measured under the following conditions.

(1) Ratio of 3 to 6 nuclei: The x sample was analyzed by a GPC analyzer, and determined from the area percentage of the peak corresponding to each component.

GPC analysis conditions Column: Shodex KF-803 (2) + KF-
802.5 (two) Column temperature: 40 ° C Solvent: tetrahydrofuran Detection: UV (254 nm) Flow rate: 1 ml / min. .

(2) Epoxy equivalent The epoxy equivalent was measured by a method according to JIS K-7236.

(3) ICI viscosity; melt viscosity at 150 ° C. in the cone plate method Measurement machine: cone plate (ICI) high temperature viscometer (RESE)
ARCH EQUIPMENT (LONDON) LTD. : 3 (measurement range: 0 to 20 poise) Sample amount: 0.15 ± 0.01 (g).

(4) Softening point Measured by a method according to JIS K-7234.

Example 1 A reaction vessel was charged with 105 parts by weight of a phenol novolak resin having a total weight of 3 to 6 nuclei of 59% by weight by column treatment, 400 parts by weight of epichlorohydrin (ECH, the same applies hereinafter), and 40 parts by weight of methanol. After heating, stirring and dissolving, the mixture was kept at 75 ° C.
Parts by weight were gradually added over 2 hours. After the completion of the addition of sodium hydroxide, the reaction was further performed at 75 ° C. for 2 hours. Then, washing with water was repeated to remove the produced salt and methanol,
Excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure, and 300 parts by weight of methyl isobutyl ketone was added to the residue and dissolved.

The solution of methyl isobutyl ketone was added to 70
After heating to 10 ° C., 10 parts by weight of a 30% by weight aqueous sodium hydroxide solution was added thereto, and the mixture was reacted for 1 hour. Then, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 145 parts by weight of the epoxy resin (E1) of the present invention. The epoxy equivalent of the obtained epoxy resin (E1) was 193 g / e.
q, softening point is 49 ° C., ICI viscosity at 150 ° C. (y) is 0.8 poise, and total weight% of 3 to 6 nuclei (x)
Was 43% by weight, and the epoxy resin component in the top peak (hereinafter simply referred to as the top peak) in the GPC measurement was a tetranuclear compound.

Example 2 The same procedure as in Example 1 was repeated except that the phenol novolak resin
The same operation as in Example 1 was carried out except that the core was 51% by weight, and the epoxy resin (E2) 14 of the present invention was used.
One part by weight was obtained. Epoxy equivalent of the obtained epoxy resin (E2) is 197 g / eq, softening point is 60 ° C, 150 ° C
Was 1.9 poise, the total weight% (x) of 3 to 6 nuclei was 36% by weight, and the epoxy resin component in the top peak was tetranuclear.

Example 3 The same procedure as in Example 1 was repeated except that the phenol novolak resin
The same operation as in Example 1 was carried out except that the core was changed to 47% by weight, and the epoxy resin (E3) 15 of the present invention was used.
2 parts by weight were obtained. The epoxy equivalent of the obtained epoxy resin (E3) is 200 g / eq, the softening point is 69 ° C., 150 ° C.
Was 4.2 poise, the total weight% (x) of 3 to 6 nuclei was 31% by weight, and the epoxy resin component in the top peak was pentanuclear.

Comparative Example 1 An epoxy resin (R1) was prepared in the same manner as in Example 1 except that the phenol novolak resin was changed to a phenol novolak resin having a softening point of 79 ° C., which was not subjected to a column treatment. Obtained. The obtained epoxy resin (R
Epoxy equivalent of 1) is 191 g / eq, softening point is 48
The ICI viscosity (y) at 150C and 0.8C was 0.8 poise, the total weight% (x) of 3 to 6 nuclei was 35% by weight, and the epoxy resin component in the top peak was a binuclear.

Comparative Example 2 An epoxy resin (R2) was prepared in the same manner as in Example 1 except that the phenol novolak resin was replaced with a phenol novolak resin having a softening point of 110 ° C., which was not subjected to a column treatment. Obtained. The obtained epoxy resin (R
Epoxy equivalent of 2) is 195 g / eq, and softening point is 65.
The ICI viscosity (y) at 4.9 ° C. and 150 ° C. was 4.9 poise, the total weight% (x) of the 3 to 6 nuclei was 25% by weight, and the epoxy resin component in the top peak was a binuclear.

Examples 4 to 6, Comparative Examples 3 to 4 Epoxy resins (E1) to (E1) obtained in Examples 1 to 3
3) and epoxy resin (R1) obtained in Comparative Examples 1-2
To (R2), a curing agent (phenol novolak resin (PN-80, manufactured by Nippon Kayaku Co., Ltd., PN-80, ICI at 150 ° C.)
Viscosity 1.5 poise, softening point 86 ° C, hydroxyl equivalent 106g
/ Eq)) was added in an amount of 1 hydroxyl group, and a curing accelerator (triphenylphosphine) was added in an amount of 1 part by weight based on 100 parts by weight of the epoxy resin. Further curing was performed at 180 ° C. for 8 hours.

Table 1 shows the results of measuring the physical properties of the cured product thus obtained.

The physical properties were measured by the following methods.

Glass transition temperature (TMA): TM-7000 manufactured by Vacuum Riko Co., Ltd. Temperature rising rate 2 ° C./min.・ Water absorption: Weight increase rate (%) after boiling a disk-shaped test specimen of 5 cm in diameter x 4 mm in water at 100 ° C for 24 hours.

[0042]

[Table 1]

Examples 7 and 8, Comparative Examples 5 and 6 Epoxy resins (E1) and (E3) of Examples 1 and 3 and epoxy resins (R1) and (R1) of Comparative Examples 1 and 2
2) Using 1 equivalent of epoxy group as a curing agent (Examples 4 to 5)
6) 1 hydroxyl equivalent, 0.2 parts by weight of curing accelerator (triphenylphosphine), 0.8 parts by weight of silane coupling agent (KBM403 manufactured by Shin-Etsu Chemical Co., Ltd.), release agent (TOA) 0.5 parts by weight of fine powder carnauba manufactured by Kasei Corporation, 2.0 parts by weight of antimony trioxide, brominated epoxy resin (Nippon Kayaku Co., Ltd.)
6.0 parts by weight of BREN-S, total weight 2
0 parts by weight of filler (FB manufactured by Denki Kagaku Kogyo KK)
-48) in the ratio (parts by weight) shown in the composition column of Table 2, kneaded with a biaxial roll, pulverized, tableted, and measured for fluidity (spiral flow value) under the following conditions. did. Table 2 shows the results.

Flowability measurement conditions Mold: conforming to EMMI-1-66 Mold temperature: 170 ° C. Transfer pressure: 70 kg / cm ² .

A cured product was obtained from the tablet in the same manner as in Examples 4 to 6, and the following properties were measured under the following conditions. Table 2 shows the results.

Glass transition temperature: same as in Examples 4 to 6.

Water absorption: Same as in Examples 4 to 6.

Bending strength: Measured at 30 ° C. according to JIS-6481 (bending strength).

Thermal expansion coefficient: Measured in the range of 40 to 110 ° C. by TMA.

[0050]

[Table 2]

The epoxy resins (E1) of Examples 1 to 3
(E3) and epoxy resins (R1) to (R2) of comparative examples
FIG. 2 shows a plot of the above-mentioned y versus x. The epoxy resin of the present invention in which the melt viscosity and the total ratio of the 3 to 6 nuclei are in a specific range exhibits higher heat resistance if the fluidity is equal to that of a known epoxy resin outside the range. When it is sufficient to develop equivalent heat resistance, it is possible to increase the amount of filler in the composition because of low viscosity, and the cured product is high as is clear in Tables 1-2. Heat resistant.

[0052]

The epoxy resin composition containing the epoxy resin of the present invention exhibits higher heat resistance as long as the fluidity is the same, as compared with the case of using a normal phenol novolak epoxy resin. When it is sufficient to develop the property, it is possible to increase the filler in the composition because of the low viscosity, and as a result, it is possible to develop performance such as low expansion, low moisture absorption, and high strength. Become. Also, when the epoxy resin is dissolved in a solvent, a viscosity equivalent to that of a known phenol novolak epoxy resin is obtained with a smaller amount of the solvent,
It is beneficial in working environment. Therefore, the epoxy resin of the present invention can be used as an insulating material for electric and electronic parts (such as a highly reliable semiconductor encapsulating material), a laminated board (such as a printed wiring board), various composite materials including CFRP, an adhesive, and a paint. Very useful when used.

[Brief description of the drawings]

FIG. 1 is a view showing the relationship between the melt viscosity of the epoxy resin of the present invention and the ratio (% by weight) of 3 to 6 nuclei to the total epoxy resin. The epoxy resin of claim 1 of the present invention exists within the range of the hatched portion in FIG.

FIG. 2 is a graph plotting the relationship between the melt viscosities of the epoxy resin of the present invention and a comparative epoxy resin and the ratio (% by weight) of 3 to 6 nuclei to the total epoxy resin. Black circles represent epoxy resins (E1) to (E3) of the present invention, and X represents epoxy resins (R1) to (R2) for comparison. The hatched portions in the figure represent the same meaning as in FIG.

 ──────────────────────────────────────────────────の Continued on the front page (72) Yoshiaki Kurimoto, Inventor 700, Shukudaidaicho, Takasaki City, Gunma Prefecture Gunei Chemical Industry Co., Ltd. (72) Inventor Akiyuki Kojima 700, Shukuodarisachimachi, Takasaki City, Gunma Prefecture Gunei Chemical Industrial Co., Ltd. Inside the company (72) Inventor Yukio Abe 700, Shukudaidaicho, Takasaki City, Gunma Prefecture Gunei Chemical Industry Co., Ltd.

Claims (7)

[Claims] 1. A compound represented by the following formula (I): (Wherein, R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and n represents a positive number having an average value of 0.1 to 20).
Melt viscosity at yC (y; poise) versus 3 in the epoxy resin
A plot of the percentage of the total weight of the ^６6 nuclei (x; weight%) is: 1) y = 60e ^−0.115X , 2) y = 1000
e- ^0.115X , 3) x = 10, 4) epoxy resin present in the region surrounded by the line of x = 70. 2. The plot of y vs. x is: 1) y = 70e
^-0.115X , 2) y = 1000e ^-0.115X , 3) x = 1
The epoxy resin according to claim 1, wherein the epoxy resin is present in a region surrounded by a line of 0, 4) x = 70. 3. The epoxy resin according to claim 1, wherein an epoxy resin component contained in a fraction constituting a top peak in GPC (gel permeation chromatography) is a trinuclear or higher nucleus. 4. The epoxy resin according to claim 1, which has a melt viscosity of 0.1 poise to 400 poise. 5. The method according to claim 1, wherein the first, second, third, or fourth aspect is selected.
An epoxy resin composition containing the epoxy resin described in the above item. 6. The epoxy resin composition according to claim 5, prepared for semiconductor encapsulation. 7. A cured product obtained by curing the epoxy resin composition according to claim 5 or 6.