JPH04323214A - Novolak resin, its production, epoxy resin, resin composition and its cured product - Google Patents

Abstract

PURPOSE:To obtain the subject resin having low melt viscosity and giving a cured material having excellent heat-resistance and moisture resistance by reacting a naphthol dimethylol compound with a naphthol compound. CONSTITUTION:The objective compound of formula III can be produced by reacting a naphthol dimethylol compound of formula I (R is H, 1-4C alkyl or aryl) (e.g. 2,4-dimethylol-1-naphthol) with a naphthol compound of formula II (e.g. 1-naphthol) preferably at a molar ratio of 1:(2-10).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin that can be used for highly reliable semiconductor encapsulation, a method for producing the same, a resin composition, and a cured product thereof.

0002

BACKGROUND OF THE INVENTION Epoxy resins are widely used in the fields of electrical and electronic parts due to their cured products having excellent electrical properties, heat resistance, adhesive properties, etc.

However, in recent years, especially with the development of the electrical and electronic fields, there has been a demand for further improvements in various properties such as heat resistance, moisture resistance, and adhesion.In order to improve these properties, epoxy resins Although many proposals have been made regarding these materials and their compositions, they are still insufficient, as cracks are likely to occur due to water absorption and thermal shock after moisture absorption.

[0004] Also, as a method for improving these physical properties,
A novolac type epoxy resin having a naphthalene skeleton has been proposed (Japanese Patent Publication No. 62-20206).
Although this proposal is excellent in terms of improving heat resistance and moisture resistance, it is difficult to control the molecular weight distribution due to the manufacturing method of epoxy resin, and the softening point and melt viscosity are high, making it difficult to work during molding. In addition to this problem, when attempting to synthesize a resin with a low softening point, there is also the problem that the content of binuclear bodies in the resin increases, which deteriorates the cured physical properties, especially the heat resistance.

[0005]

[Problems to be Solved by the Invention] The present invention is useful as a highly reliable semiconductor encapsulation device that has a controlled molecular weight distribution, has excellent fluidity when melted, and has excellent heat resistance and moisture resistance in its cured product. The present invention provides a resin, a method for producing the same, a resin composition, and a cured product.

[0006]

[Means for Solving the Problems] The present inventors have completed the present invention as a result of intensive research into methods for imparting and improving the above characteristics. That is, the present invention provides formula (1)

[
0007

[C5]

(However, n represents a value of 0 to 10, and R each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms,
or represents an aryl group, and R may be the same or different. ) In the novolac type resin represented by the formula (
Contains 30% by weight or more of the component n=1 of 1), and has the formula (1)
), a novolac type resin in which the content of the n=0 dinuclear component is 10% by weight or less, (2) formula (2)

[0009]

[C6]

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group.) and a naphthol dimethylol compound represented by the formula (N)

[0011]

[C7]

The novolak according to (1) above, which is reacted with a naphthol represented by the formula (wherein R represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group) Manufacturing method of mold resin, (3) Formula (3)

00
13]

[Chemical formula 8]

(However, n represents a value of 0 to 10, and R each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms,
or represents an aryl group, and R may be the same or different. ) A novolac type epoxy resin represented by formula (3) containing 30% by weight or more of the component where n=1, and the content of the binuclear component where n = 0 in formula (3) is 10% by weight
Novolac type epoxy resin, which is:

[0015](
4) In an epoxy resin composition containing an epoxy resin, a curing agent, and if necessary a curing accelerator, the novolac type epoxy resin of (3) above is contained as the epoxy resin, or
and/or an epoxy resin composition containing the novolac type resin of (1) above as a curing agent,

(5)
The present invention relates to a cured product of the epoxy resin composition described in (4) above.

The novolac type resin of (1) above is the above (1).
It can be obtained by the production method 2), that is, by subjecting the naphthol dimethylol compound of formula (2) and the naphthol of formula (N) to a dehydration condensation reaction in the presence of an acid catalyst.

The naphthol dimethylol compound represented by formula (2) is a known compound, and can be synthesized, for example, by reacting naphthol with formaldehyde in the presence of an alkali metal hydroxide.

Examples of the naphthol dimethylol compound of formula (2) include 2,4-dimethylol-1-naphthol.

Examples of the naphthols of formula (N) include 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methyl-1-naphthol, and the amount of these naphthols used is less than naphthol dimethylol. The amount is preferably 1 to 20 times, particularly preferably 2 to 10 times by mole, per mole of body.

Acid catalysts used in the dehydration condensation reaction include protonic acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and para-toluenesulfonic acid; Lewis acid catalysts such as boron trifluoride, boron trifluoride ether complex, zinc chloride, and aluminum chloride; Acid, acetic acid, oxalic acid, etc. can be used. Among these, hydrochloric acid, para-toluenesulfonic acid, oxalic acid, etc. are preferably used, and the amount of the acid catalyst used is preferably selected between 0.001 and 0.1 moles relative to the naphthol dimethylol compound.

[0022] The condensation reaction between this naphthol dimethylol compound and naphthols in the presence of an acid catalyst is usually 20 to 1
The reaction is carried out at a temperature between 20°C, preferably 30°C to 80°C, and the reaction time can usually be selected within the range of 1 to 10 hours. Further, this reaction is preferably carried out in the presence of a suitable solvent such as water, methanol, methyl isobutyl ketone, toluene, and the like. The amount of the solvent to be used is not particularly limited, but it is usually used in an amount of 1 to 30 times the weight of the naphthol dimethylol compound.

Furthermore, the condensation reaction solution is repeatedly washed with water in the presence of excess solvents such as toluene and methyl isobutyl ketone until the system becomes neutral, and after the water is separated and drained, the solvent and unreacted substances are removed under heating and reduced pressure. , the novolac type resin of (1) above is obtained.

[0024] The trinuclear body of this novolac type resin (formula (1)
The content of the compound (where n=1) is 30% by weight or more, preferably 40% by weight or more, particularly preferably 50% by weight or more. Further, the content of dinuclear bodies (compounds where n=0 in formula (1)) is 10% by weight or less, preferably 5% by weight or less.

The novolac type epoxy resin of the above (3) of the present invention can be synthesized by reacting the novolak type resin of the above (1) with epihalohydrin. Examples of the epihalohydrin include epichlorohydrin and epibromohydrin, but epichlorohydrin, which is industrially easily available, is preferred. This reaction can be carried out in accordance with a conventionally known method for obtaining polyglycidyl ether from a novolac type phenol resin and epihalohydrin.

For example, a solid alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to the mixture of the novolak type resin in (1) above and excess epichlorohydrin, or while being added, the mixture is heated at 20°C to 120°C. The reaction is carried out at a temperature between At this time, an aqueous solution of the alkali metal hydroxide may be used. In that case, the alkali metal hydroxide is continuously added and water and epichlorohydrin are continuously added from the reaction system under reduced pressure or normal pressure. A method may also be used in which the water is removed by distillation, followed by liquid separation, and the epichlorohydrin is continuously returned to the reaction system.

In the above method, the amount of epichlorohydrin used is usually 1 to 20 mol, preferably 2 to 10 mol, per equivalent of hydroxyl group in the novolak resin. The amount of alkali metal hydroxide used is generally 0.8 to 1.5 mol, preferably 0.9 to 1.1 mol, per equivalent of hydroxyl group in the novolak resin. Furthermore, in order to make the reaction proceed smoothly, it is preferable to add an aprotic polar solvent such as dimethyl sulfone, dimethyl sulfoxide (hereinafter referred to as DMSO) in addition to alcohols such as methanol and ethanol. It will take place over a period of 20 hours.

Alternatively, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride or the like can be added as a catalyst to a mixture of novolak type resin and excess epihalohydrin, and the reaction can be carried out at 50 to 150°C. A solid or aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to the halohydrin ether of the novolac type resin and reacted again at a temperature between 20 and 120°C to form a halohydrin ether. The glycidyl ether of the novolac type resin can also be obtained by ring closure. In this case, the amount of quaternary ammonium salt used is preferably 0.0 per equivalent of hydroxyl group of the novolac type resin.
The amount can be selected within the range of 0.01 to 0.1 mole.

Usually, these first-stage reactants are washed with water, or after removing excess epihalohydrin by heating under reduced pressure without washing with water, they are dissolved again in a solvent such as toluene or methyl isobutyl ketone, and dissolved in sodium hydroxide and water. A second reaction is carried out by adding an aqueous solution of an alkali metal hydroxide such as potassium oxide. In this case, the amount of alkali metal hydroxide used is usually 0.0 per mole of hydroxyl group in the novolak resin used.
The amount is 1 to 0.2 mol, preferably 0.05 to 0.1 mol. In addition, the reaction temperature is usually carried out between 50 and 120°C,
The reaction time is usually 0.5 to 2 hours.

After the completion of the reaction, the by-produced salts are removed by filtration, washing with water, etc., and the novolac type epoxy resin of the present invention can be obtained by distilling off solvents such as toluene and methyl isobutyl ketone under heating and reduced pressure. I can do it.

[0031] The trinuclear body of this novolac type epoxy resin (
The content of the compound (n=1 in formula (3)) is 30% by weight or more, preferably 40% by weight or more, particularly preferably 50% by weight or more. In addition, a dinuclear body (n=0 in formula (3)
The content of the compound) is 10% by weight or less, preferably 5% by weight or less.

The epoxy resin composition of the present invention will be explained below. In the epoxy resin composition of (4) above, when using the novolac type epoxy resin of the above (3) of the present invention, the novolac type epoxy resin of the present invention may be used alone or in combination with other epoxy resins. Can be done. When used together, the proportion of the novolac type epoxy resin of the present invention in the total epoxy resin is preferably 30% by weight or more, particularly preferably 40% by weight or more.

Other epoxy resins that can be used in combination with the novolak epoxy resin of the present invention include novolac epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, alicyclic epoxy resins, Examples include biphenyl epoxy resins, but novolak epoxy resins are particularly advantageous in terms of heat resistance. Specific examples thereof include, but are not limited to, cresol novolac type epoxy resins, phenol novolac type epoxy resins, brominated phenol novolac type epoxy resins, and the like. These may be used alone or in combination of two or more.

[0034] In the epoxy resin composition (4) above, when the novolac type resin of the present invention (1) is used, the novolak type resin of the present invention is used alone or in combination with other curing agents. be able to. When used together, the proportion of the novolac type resin of the present invention in the total curing agent is 3.
The content is preferably 0% by weight or more, particularly preferably 40% by weight or more.

Other curing agents that can be used in combination with the novolac type resin of the present invention include, for example, polyamine curing agents such as aliphatic polyamines, aromatic polyamines, polyamide polyamines, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, etc. Examples include, but are not limited to, acid anhydride curing agents such as phenol novolak, phenol curing agents such as cresol novolac, Lewis acids such as boron trifluoride or their salts, and dicyandiamides. It's not a thing. These may be used alone,
Two or more types may be used in combination.

In the epoxy resin composition of the present invention, the amount of curing agent used is preferably 0.5 to 1.5 equivalents, particularly 0.6 to 1.2 equivalents per equivalent of epoxy groups in the epoxy resin.
Equivalent amounts are preferred.

[0037] A curing accelerator is used as necessary, and 2-
Various known curing accelerators can be used, including imidazole compounds such as methylimidazole and 2-ethylimidazole, tertiary amine compounds such as 2-(dimethylaminomethyl)phenol, and triphenylphosphine compounds, and are not particularly limited. It's not a thing. When using a curing accelerator, the amount used is 0.01 parts by weight per 100 parts by weight of the epoxy resin.
A range of 15 parts by weight is preferred, and a range of 0.1 to 10 parts by weight is particularly preferred.

[0038] The epoxy resin composition of the present invention may further contain known additives as required. Examples of additives include inorganic fillers such as silica, alumina, talc, and glass fiber; Examples include surface treating agents for fillers such as silane coupling agents, mold release agents, and pigments.

The epoxy resin composition of the present invention is obtained by uniformly mixing each component, and usually has a molecular weight of 130 to 170
By carrying out preliminary curing at a temperature of 150 to 200° C. for 30 to 300 seconds and further post-curing at a temperature of 150 to 200° C. for 2 to 8 hours, a sufficient curing reaction proceeds and the cured product of the present invention is obtained. Alternatively, the components of the epoxy resin composition can be uniformly dispersed or dissolved in a solvent, and the composition can be cured after removing the solvent.

The cured product thus obtained has excellent performance, having both heat resistance and moisture resistance. Moreover, the effect is doubled by using the resin of the present invention for both the epoxy resin component and the curing agent component. Therefore, the above (1) or (3) of the present invention
The resin is used in a wide range of fields where heat resistance and moisture resistance are required.
It can be used as an epoxy resin or as a curing agent. Specifically, it is useful as a compounding component of all electrical and electronic materials such as insulating materials, laminates, and sealing materials. Moreover, it can be used in fields such as molding materials and composite materials.

[0041]Furthermore, the resin of the above (1) or (3) of the present invention has a low softening point despite having a naphthol ring, so conventional methods such as transfer molding can be used. The workability is also good.

[0042]

[Examples] The present invention will be explained in more detail below with reference to Examples. In addition, the softening point in the examples is JIS K242.
5 (ring and ball method), and the hydroxyl equivalent and epoxy equivalent are shown in g/eq. Note that the present invention is not limited to these Examples.

Example 1 (1) Synthesis of naphthol dimethylol compound 144 parts by weight (1 mol) of 1-naphthol and 212 parts by weight of a 20 wt% sodium hydroxide aqueous solution were placed in a flask equipped with a thermometer, a cooling tube, a dropping funnel, and a stirrer. Part by weight (1.06 mol) was charged and reacted at 40°C for 30 minutes. Next, the inside of the system was cooled to 10°C, and granular paraformaldehyde (purity 92% by weight) 6
8 parts by weight (1.05 mol) was added at once and reacted for 2 hours.

After the reaction was completed, a portion of this reaction solution was neutralized and analyzed by liquid chromatography (reversed phase-RI), which revealed that the naphthol dimethylol compound [formula (2)] was 95% (area %). It turns out.

(2) Synthesis of novolac type resin 600 parts by weight of methyl isobutyl ketone was added to the above reaction solution, and then 576 parts by weight (4 mol) of 1-naphthol was charged.
Furthermore, 100 parts by weight of a 38 wt% hydrochloric acid aqueous solution (1.04 parts by weight)
mol) was added over 30 minutes while being careful not to generate heat to effect neutralization. Next, the inside of the system was heated to 40°C, 5 parts by weight of a 38 wt % aqueous hydrochloric acid solution was added, and the mixture was further reacted at 60°C for 2 hours.

After the reaction was completed, water washing was repeated several times to return to neutrality. Thereafter, methyl isobutyl ketone and unreacted 1-naphthol were removed from the oil layer under heating and reduced pressure using a rotary evaporator to obtain 195 parts by weight of a novolac type resin (A) that was brown and solid at room temperature. The ICI viscosity of the obtained novolac type resin (A) at 150°C is 16p.
s, the softening point was 110.5°C, and the hydroxyl equivalent (OH equivalent) was 153.

[0047] Further, this novolac type resin (A) was subjected to the following GPC using tetrahydrofuran (hereinafter referred to as THF) as a solvent.
When analyzed using an analyzer, a molecular weight distribution curve shown in FIG. 1 was obtained.

GPC device liquid pump: LC-6000
(Manufactured by Hitachi) Column: GPC
KF-803 (1 piece) + GPC KF-802.
5 (2 pieces) +GPC KF
-802 (1 piece) (manufactured by Showa Denko) Column temperature: 40°C Solvent: THF 1ml/min Detector: RI ERC-7510
(Manufactured by Elma Optical) Data processing: D-2500
(Manufactured by Hitachi)

00
49] Novolak type resin analyzed under the above analysis conditions (
The retention time of the main peak in A) corresponds to the molecular weight of a trinuclear substance having three naphthol rings, based on a calibration curve using standard polystyrene, and the peak component that is thought to be this trinuclear substance was fractionated, and the mass spectrum ( When analyzed by FAB-MS), M+ 456 was obtained, confirming that this component was a trinuclear body represented by formula (4). Further, the content of the trinuclear substance in the novolac type resin (A) was 68% by weight, and the content of the dinuclear substance was 4% by weight.

[0050]

[Chemical formula 9]

(3) Synthesis of novolac type epoxy resin Next, the novolac type resin (A) 1 obtained in this way
Add 555 parts by weight (6 mol) of epichlorohydrin and 140 parts by weight of DMSO to 53 parts by weight, dissolve and heat to 50°C, and add 42 parts by weight (1.04 mol) of flaky sodium hydroxide (99% purity) for 100 minutes. After that, the reaction was further carried out at 60°C for 2 hours and at 80°C for 1 hour. Next, after repeatedly washing with water to return to neutrality, excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure using a rotary evaporator. This residue was then given 50
0 parts by weight of methyl isobutyl ketone was added and dissolved.

Further, this methyl isobutyl ketone solution was heated to 80° C., 10 parts by weight of a 30% by weight aqueous sodium hydroxide solution was added, and after reacting for 1 hour, the solution was made neutral by repeated washing with water. Next, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 193 parts by weight of novolac type epoxy resin (B). The obtained novolac type epoxy resin (B) has an ICI viscosity of 4 at 150°C.
ps, the softening point was 83.5°C, and the epoxy equivalent was 215.

This novolac type epoxy resin (B) was analyzed by liquid chromatography (GPC, the analysis conditions were the same as those for the above-mentioned novolak resin), and the molecular weight distribution curve shown in FIG. 2 was obtained. In addition, when the peak component thought to be a trinuclear substance was fractionated and analyzed by mass spectrometry (FAB-MS), M+ 624 was obtained, indicating that this component is a trinuclear substance represented by formula (5). It was confirmed. or,
The content of this trinuclear substance in the novolac type epoxy resin (B) was 59% by weight, and the content of the dinuclear substance was 4.3% by weight.

[0054]

[Chemical formula 10]

Comparative Example 1 (1) Synthesis of novolac type resin 144 parts by weight (1 mol) of 1-naphthol and 67 parts by weight of formalin (purity 30% by weight) were placed in a flask equipped with a thermometer, cooling tube, dropping funnel, and stirrer. The preparation system is 40
The temperature was raised to ℃. Next, 2 parts by weight of para-toluenesulfonic acid was added, and the mixture was reacted at 40°C for 1 hour and then at 70°C for 4 hours.

After the reaction was completed, 500 parts by weight of methyl isobutyl ketone was added to the reaction mixture, and the mixture was washed with tap water several times to return to neutrality. Thereafter, methyl isobutyl ketone and unreacted 1-naphthol were removed from the oil layer using a rotary evaporator under heating and reduced pressure to obtain 150 parts by weight of novolac type resin (C) which was brown and solid at room temperature. I of the obtained novolac type resin (C) at 150°C
The CI viscosity was 40 ps or more, the softening point was 114°C, and the hydroxyl equivalent (OH equivalent) was 152.

When this novolak type resin (C) was analyzed by liquid chromatography (GPC, analysis conditions were the same as in Example 1), a molecular weight distribution curve shown in FIG. 3 was obtained. In addition, a peak component believed to be a trinuclear substance was fractionated and analyzed by mass spectrometry (FAB-MS), and it was found to be M+ 45.
By obtaining 6, it was confirmed that this component was a trinuclear body of 1-naphthol represented by formula (4). or,
The content of this trinuclear body in the novolac type resin (C) is 19
The content of binuclear bodies was 30% by weight.

(2) Synthesis of epoxy resin Epoxidation reaction was carried out in the same manner as in Example 1 except that 152 parts by weight of the above novolac type resin (C) was used.
0 parts by weight were obtained. 150 of the obtained epoxy resin (D)
The ICI viscosity at °C was 8 ps, the softening point was 92 °C, and the epoxy equivalent was 227.

When this epoxy resin (D) was analyzed by liquid chromatography (GPC, analysis conditions were the same as in Example 1), the molecular weight distribution curve shown in FIG. 4 was obtained. or,
When a peak component that was thought to be a trinuclear body was fractionated and analyzed by mass spectrometry (FAB-MS), M+ 624 was obtained, indicating that this component is 3 expressed by formula (5)
It was confirmed that it was a nuclear body. Further, the content of the trinuclear substance in the epoxy resin (D) was 16% by weight, and the content of the dinuclear substance was 29% by weight.

Test Examples 1-2, Comparative Examples 1-2 Above Example 1
and Resins (A) to (D) obtained in Comparative Example 1, commercially available curing agent PN-80 (phenol novolac resin (Nippon Kayaku)
Co., Ltd., ICI viscosity 1.5 ps at 150°C, softening point 86°C, hydroxyl equivalent 106) or epoxy resin EOC
N1020 (o-cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 200, ICI viscosity at 150°C 3.2 ps) and curing accelerator (triphenylphosphine) were blended in the proportions shown in Table 1. Then, a resin molded body was prepared by transfer molding, and further cured under the curing conditions shown in Table 1.The results of measuring the heat distortion temperature and water absorption of the cured product thus obtained are shown in Table 1.
Shown below.

[0061]
Table 1
Test example
Comparative example
1
2 1
2 Resin (A) wt part
150 Resin (B) wt part
150 Resin (C) wt part

150 Resin (D) wt part

150 EOC
N1020 wt part 196
197 PN-80
wt part 7
4 70
Curing accelerator wt part 2.0
1.5 2.0 1.5
Curing conditions 160℃×
2 hours + 180℃ x 8 hours Heat distortion temperature (℃) *1
177 175 172
171 Water absorption rate (wt%) *2
0.95 0.96 1.07
1.00

*1 JIS K72
Value according to 07 (°C) *2 Disc of thickness 3mm * diameter 50mm, boiling water 2
Water absorption rate after 4 hours (wt%)

[0063]

Effects of the Invention The novolac type resin and novolac type epoxy resin of the present invention have a viscosity at the time of melting (IC at 150°C).
Despite the low viscosity and improved fluidity,
The cured product can have excellent heat resistance and moisture resistance. Further, according to the production method of the present invention, it is possible to easily obtain a resin with a controlled molecular weight distribution in which the trinuclear content is 30% by weight or more and the dinuclear content is 10% by weight or less.

[Brief explanation of the drawing]

Figure 1 Molecular weight distribution curve of novolak type resin (A) by GPC analysis Figure 2 Molecular weight distribution curve of novolac type epoxy resin (B) by GPC analysis Figure 3 Molecular weight distribution curve of novolac type resin (C) by GPC analysis Figure 4 Epoxy resin (D) Molecular weight distribution curve by GPC analysis

Claims (5)

[Claims] Claim 1: Formula (1) [Formula 1] (where n represents a value of 0 to 10, R each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group, R may be the same or different.)
In the novolac type resin represented by the formula (1), n=1
A novolac-type resin containing 30% by weight or more of the component and having a content of the binuclear component of formula (1) where n=0 is 10% by weight or less. [Claim 2] A naphthol dimethylol compound represented by formula (2) [Chemical formula 2] (wherein R represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group) and formula (N) 3. The novolak according to claim 1, wherein the novolak is reacted with a naphthol represented by: Method of manufacturing mold resin. [Claim 3] Formula (3) [Formula 4] (where n represents a value of 0 to 10, R each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group; R may be the same or different.) Contains 30% by weight or more of the component where n=1 in formula (3), and where n in formula (3)
A novolak-type epoxy resin in which the content of the binuclear component with =0 is 10% by weight or less. 4. An epoxy resin composition containing an epoxy resin, a curing agent, and optionally a curing accelerator, which contains the novolac type epoxy resin of claim 3 as the epoxy resin and/or the novolac type epoxy resin of claim 1 as the curing agent. An epoxy resin composition containing a novolac type resin. 5. A cured product of the epoxy resin composition according to claim 4.