JPH0853532A - Epoxy resin, its production and epoxy resin composition - Google Patents

Abstract

PURPOSE:To produce an epoxy resin having a high crosslinking density and a high glass transition temperature, excellent in heat resistance and useful for, e.g. electric and electronic components by reacting a specified polyvalent phenolic compound with an epihalohydrin. CONSTITUTION:This epoxy resin of formula II (G is glycidyl) is produced by reacting a polyvalent phenolic compound represented by formula I [R1 is a 1 to 12C alkyl; R2 is H, OH or a 1 to 4C alkyl; n is 1 or 2] with an epihalohydrin. In addition, the epoxy resin composition is obtained by blending this epoxy resin with a curing agent such as a novolak type phenol resin and a curing promoter.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin, a method for producing the same, and an epoxy resin composition. Specifically, it relates to an epoxy resin having a high degree of heat resistance, a method for producing the same, and an epoxy resin composition.

[0002]

2. Description of the Related Art Epoxy resins have hitherto been used in various applications such as paints, laminated plates and electric / electronic materials. Various kinds of such epoxy resins are known, but the cresol novolac type epoxy resin which is generally used can be sufficiently satisfied in terms of heat resistance as the use conditions of electric and electronic devices become severe. It's gone. For cresol novolac type epoxy resin, etc., in order to increase the heat resistance, the crosslink density is increased and a rigid structure with less freedom is introduced into the molecular chain, but there is a limit to improving the heat resistance. However, when higher heat resistance is required, it is not possible to adequately cope with it.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an epoxy resin whose cured product has a high degree of heat resistance, a method for producing the same, and an epoxy resin composition.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that an epoxy resin having a specific structure represented by the following general formula (1) is used. Have found that the object of the present invention can be achieved. The present invention has been completed based on this new finding.

That is, the present invention has the general formula (1):

[0006]

[Chemical 3]

(Wherein G is a glycidyl group, R ₁ is an alkyl group having 1 to 12 carbon atoms, R ₂ is a hydrogen atom, a hydroxy group or an alkyl group having 1 to 4 carbon atoms, and n is 1 or 2). Represents an integer of), a general formula (2):

[0008]

[Chemical 4]

(In the formula, R ₁ is an alkyl group having 1 to 12 carbon atoms, and R ₂ is a hydrogen atom, a hydroxy group or 1 to 12 carbon atoms.
4 represents an alkyl group, and n represents an integer of 1 or 2. ) A polyhydric phenolic compound represented by the formula) is reacted with epihalohydrin, and a method for producing the epoxy resin, and an epoxy containing the epoxy resin, a novolac type phenol resin as a curing agent, and a curing accelerator. It relates to a resin composition.

The epoxy resin represented by the general formula (1) of the present invention can be obtained by reacting a polyhydric phenol compound represented by the general formula (2) with epihalohydrin.

First, the polyhydric phenol compound represented by the general formula (2) will be described. The polyphenol compound represented by the general formula (2) has the general formula (3):

[0012]

[Chemical 5]

2,6-diformyl-4-alkylphenol represented by the formula (wherein R ₁ represents an alkyl group having 1 to 12 carbon atoms) and the general formula (4):

[0014]

[Chemical 6]

(Wherein R ₂ represents a hydrogen atom, a hydroxy group or an alkyl group having 1 to 4 carbon atoms) is easily subjected to a condensation reaction in the presence of an acid catalyst. Can be manufactured.

Specific examples of the 2,4-diformyl-4-alkylphenol represented by the general formula (3) include 2,6
-Diformyl-4-methylphenol, 2,6-diformyl-4-ethylphenol, 2,6-diformyl-4
-N-propylphenol, 2,6-diformyl-4-
i-Propylphenol, 2,6-diformyl-4-n
-Butylphenol, 2,6-diformyl-4-t-butylphenol, 2,6-diformyl-4-octylphenol, 2,6-diformyl-4-nonylphenol, 2,6-diformyl-4-dodecylphenol and the like can be mentioned. The 2,6-diformyl-4-alkylphenol is produced by oxidizing 2,6-dimethylol-4-alkylphenol in the presence of a catalyst such as palladium, platinum or manganese dioxide (Japanese Examined Patent Publication No. 60- 29371, Japanese Patent Publication No. 4-43059).

Specific examples of the phenols represented by the general formula (4) include phenol, resorcinol, pyrogallol and the like, cresols such as o-cresol, m-cresol and p-cresol, 2,3-xylenol,
2,4-xylenol, 2,5-xylenol, 2,6
Xylenol, 3,4-xylenol, 3,5-xylenol, and other xylenols, ethylphenol, n
-Propylphenol, i-propylphenol, n-
Examples thereof include various alkylphenols such as butylphenol and t-butylphenol. These phenols may be used alone or in combination of two or more.

The amount of phenols used is usually 2,6-
The amount is about 4 to 60 parts by mole, preferably 8 to 32 parts by mole with respect to 1 part by mole of diformyl-4-alkylphenol. If it is less than 4 parts by mole, the production of high molecular weight substances will increase, and if it exceeds 60 parts by mole, the reaction rate will be slow and the reaction will take a long time, which is not preferable.

Examples of the acid catalyst used in the condensation reaction include organic acids, inorganic acids, metal salts, Lewis acids and the like. Specifically, as organic acids, formic acid, oxalic acid, malonic acid,
Examples include succinic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, paratoluenesulfonic acid, benzenesulfonic acid, phenolsulfonic acid, xylenesulfonic acid, trifluoromethanesulfonic acid, and the like, and inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, Examples include perchloric acid, hydrobromic acid, phosphoric acid, etc., examples of metal salts include zinc acetate, zinc chloride, magnesium acetate, etc., examples of Lewis acids include boron trifluoride, titanium tetrachloride, aluminum chloride, etc. can give. Among these, it is preferable to use a strong acid catalyst such as p-toluenesulfonic acid or hydrochloric acid, since the selectivity is particularly good and the reaction rate can be controlled appropriately. The amount of the acid catalyst used is usually 0.001 to 10 parts by weight based on 100 parts by weight of 2,6-diformyl-4-alkylphenol because the reaction rate is appropriately controlled and the production of by-products can be suppressed. Degree, preferably 0.01 to 5
It is considered to be part by weight.

In using the above catalyst,
A suitable cocatalyst may be used. Specific examples of the cocatalyst include thioglycolic acid, thioglycerol, thiols such as benzenethiol. Among these,
It is preferable to use thioglycolic acid from the viewpoint of easy post-treatment and solubility. The amount of the co-catalyst used appropriately controls the reaction rate and suppresses the formation of by-products,
It is usually about 10 parts by weight or less, preferably about 0.001 to 5 parts by weight, based on 100 parts by weight of 2,6-diformyl-4-alkylphenol.

A solvent is not particularly required in the condensation reaction, but the reaction may be carried out using a suitable solvent. Specific examples of the solvent used include water, methyl alcohol, ethyl alcohol, isopropyl alcohol,
Examples thereof include alcohols such as butyl alcohol and isoamyl alcohol, glycol ethers such as ethyl cellosolve acetate, ethyl cellosolve and methyl cellosolve, and hydrocarbons such as hexane, cyclohexane, heptane, benzene, toluene and xylene.

The reaction temperature is usually about 20 to 200 ° C. The reaction rate is appropriately controlled and the production of by-products can be suppressed, so that the temperature is preferably 50 to 100 ° C.

After completion of the reaction, an alkaline substance is added to neutralize the acid catalyst (the acid catalyst and the cocatalyst when the cocatalyst is used). As the alkaline substance used,
Examples thereof include alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkali metal hydrogen carbonates, alkaline earth metal carbonates, ammonia, and organic amines. Among these, alkali metal hydroxides such as sodium hydroxide are preferable because they have few side reactions and are easy to handle. The alkaline substance may be added as it is, or may be added as an aqueous solution, but it is usually 0.
It may be added as an aqueous solution of about 1 to 50% by weight, preferably 1 to 20% by weight.

After neutralization, an organic solvent or the like is added to the system to dissolve the reaction product, and the salt or metal ion produced by neutralization with water is washed. As the organic solvent, ethyl acetate, tetrahydrofuran, chloroform, methyl isobutyl ketone, benzene, toluene, xylene, hexane, heptane, cyclohexane and the like are preferable, and as water, ion exchanged water is preferable.

Thus, the polyhydric phenol compound represented by the general formula (2) can be obtained. In the reaction product, in addition to the polyhydric phenol compound represented by the general formula (2), It contains unreacted phenols. Such unreacted phenols can be easily removed by vacuum distillation, steam distillation, etc., and the novel polyhydric phenol compound represented by the general formula (2) can be easily isolated.
The novel polyhydric phenol compound represented by the general formula (2) is a high molecular weight compound obtained by condensing the polyhydric phenol compound with unreacted 2,6-diformyl-4-alkylphenol together with phenols and the like. Etc. may be included.
Such high molecular weight substances and the like can be removed by means such as reprecipitation and recrystallization, but the mixture can also be used.

The softening point of the curing agent containing the polyhydric phenol compound represented by the general formula (1) is usually 50 to 28.
0 ° C., preferably 70 to 150 ° C., and the hydroxyl value (hydroxyl group equivalent) is usually 200 to 700 (280 to 80),
It is preferably 400 to 600 (140 to 90).

In the obtained polyhydric phenol compound represented by the general formula (2) of the present invention, R ₁ has ₁ carbon atom.
To 12, preferably 1 to 4 alkyl groups, and R ₂ represents a hydroxy group or a C1 to C4 alkyl group. R ₁
When the number of carbon atoms in the compound exceeds 12, the heat resistance of the cured product of the epoxy resin represented by the general formula (1) produced from the polyhydric phenol compound represented by the general formula (2) decreases. Is not preferred. When the carbon number of R ₂ exceeds 4, the reactivity with 2,6-diformyl-4-alkylphenol decreases, which is not preferable. The polyhydric phenol compound represented by the general formula (2) may be a compound in which one kind of compounds having the same orientation is used as the phenols, or may be a mixture using phenols having different R ₂ . When two or more compounds having different orientations are used as phenols, a mixture of several kinds of polyhydric phenol compounds according to the orientation of each phenol is obtained.

The epoxy resin of the present invention represented by the general formula (1) is obtained by the above-mentioned general formula (2).
It can be obtained by reacting a polyhydric phenol compound represented by with epihalohydrin. Hereinafter, this reaction will be described in detail.

First, the polyhydric phenol compound represented by the general formula (2) is dissolved in epihalohydrin to form a uniform solution. The amount of epihalohydrin used is about 0.8 to 20 parts by weight with respect to 1 part by weight of the polyhydric phenol compound represented by the general formula (2). Further, about 0.2 to 10 parts by weight of the basic compound or about 0.001 to 0.5 parts by weight of the quaternary ammonium salt is added to 1 part by weight of the polyhydric phenol compound represented by the general formula (2). Usually added at a reaction temperature of 30 to 1 as a solid or aqueous solution.
The reaction is carried out at 10 ° C for 0.5 to 4 hours. Then, 0.2 to 10 parts by weight of the basic compound is added as a solid or an aqueous solution, and the reaction is performed at 50 to 80 ° C. Usually, at this time, the reaction is carried out while azeotropically distilling the reaction liquid under reduced pressure while maintaining a predetermined temperature, and the condensate obtained by cooling the vaporized vapor is separated into oil and water to remove the oil content without water. Dehydration is performed by the method of returning to the reaction system. When the basic compound is added, it is added intermittently or continuously over 30 minutes to 8 hours in order to suppress a rapid reaction. After completion of the reaction, the insoluble by-product salt is removed by filtration or washed with water, and then unreacted epihalohydrin is distilled off under reduced pressure to obtain the epoxy resin of the present invention represented by the general formula (1). To be Although this reaction does not require a solvent, benzene,
There is no problem even if a solvent such as toluene, xylene, propyl ether, butyl ether, isopropyl alcohol, butyl alcohol, tetrahydrofuran, chloroform, dimethylsulfoxide is used.

Examples of the epihalohydrin used in the reaction include epichlorohydrin, epibromhydrin, epiyodohydrin, epifluorohydrin, etc., but epichlorohydrin is industrially preferable.

Examples of the basic compound include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide; primary amines such as methylamine, ethylamine, propylamine, butylamine, benzylamine and aniline; dimethylamine. , Secondary amines such as diethylamine, N-methylaniline and benzylmethylamine; tertiary amines such as trimethylamine, triethylamine, N, N-dimethylaniline and dimethylbenzylamine; or hydrochlorides and hydrobromides of these amines , Hydrogen fluoride, sulfates and the like; imidazoles such as 2-phenylimidazole; phosphonium salts such as ethyltriphenylphosphonium iodide; and phosphines such as triphenylphosphine. Further, as the quaternary ammonium salt, tetramethylammonium chloride,
Examples thereof include chlorinated compounds such as tetraethylammonium, tetrapropylammonium, tetrabutylammonium, benzyltrimethylammonium, benzyltriethylammonium, allyltriethylammonium, brominated compounds, fluorinated compounds and sulfates. A quaternary ammonium salt is preferable in the above-mentioned reaction. As the basic compound used in the reaction in the latter stage, those exemplified above can be used, and among the basic compounds, alkali metal hydroxides are preferable.

The softening point of the epoxy resin represented by the general formula (1) used in such an epoxy resin composition is 70 to 1
The epoxy equivalent is about 20 ° C. and about 150 to 300.

The epoxy resin composition of the present invention comprises the epoxy resin represented by the general formula (1), a novolac-type phenol resin as a curing agent, and a curing accelerator.

As the novolak type phenol resin used as the curing agent, a known one obtained by addition-condensing the phenols represented by the general formula (4) and formaldehyde under acidic conditions can be used. The novolac type phenolic resin has a number average molecular weight of about 450 to 1000 and a softening point of about 70 to 100 ° C.

Further, in the present invention, a curing accelerator is used in order to accelerate the curing reaction between the epoxy resin represented by the general formula (1) and the novolac type phenol resin used as the curing agent. Examples of the curing accelerator include 1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol and the like. Tertiary amines; 2
-Methylimidazole, 2-phenylimidazole, 2
-Imidazoles such as phenyl-4-methylimidazole and 2-heptadecylimidazole; organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine and phenylphosphine; tetraphenylphosphonium tetraphenylborate, 2- Examples thereof include tetraphenylboron salts such as ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate.

Next, the use ratio of each of the above-mentioned components of the epoxy resin composition of the present invention will be described. Usually, it is used such that the hydroxyl group equivalent of the curing agent is 0.5 to 1.5 equivalents per 1 equivalent of epoxy equivalent of the epoxy resin represented by the general formula (1). If the proportion of the curing agent used is less than 0.5 equivalent, the curing rate will be slow, and if it exceeds 1.5 equivalents, a gelation reaction may occur, which is not preferable. The curing accelerator is used in a proportion of 0.1 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin represented by the general formula (1). If the proportion of the curing accelerator used is less than 0.1 parts by weight, the effect of promoting the curing is scarce, and if it exceeds 5 parts by weight, the heat resistance and mechanical properties of the cured product tend to be impaired, such being undesirable.

In addition, various solvents, fillers, mold release agents, surface treatment agents, flame retardants, etc. may be added to the epoxy resin composition as required. The epoxy resin composition is
Usually, it is prepared by heating and mixing using a roll, a kneader or the like.

[0038]

The cured product of the epoxy resin composition of the present invention has a high cross-linking density and a high glass transition point, and is therefore excellent in high heat resistance. Since such an epoxy resin composition has excellent heat resistance, for example, molded products (sealing materials for semiconductors, transfer molded products for various electronic components, insulating materials for electrical / communication devices, pistons for brakes as automobile components, and Household products such as timing gears, kettles and iron handles), adhesives (copper adhesives for printed circuit boards,
Adhesives for structural materials for automobiles and aircraft), laminated products (printed circuits, structural materials for automobiles and aircraft, fuel tanks, pipes,
Storage tanks, pressure-resistant containers, etc.), paints (automotive paints, solvent-free paints, high-solid paints, powder paints, water-based emulsion paints), baking paints (protective paints for chemical equipment, various linings, electrical insulating varnishes) Can be used.

[0039]

EXAMPLES The present invention will be described in more detail below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples.

Production Example 1 99.49 g of 2,6-diformyl-4-methylphenol and 912.58 of phenol were placed in a reaction vessel connected with a stirrer, a reflux condenser, a mercury thermometer and a nitrogen gas introducing tube.
g was charged and stirred at room temperature under a nitrogen stream, and when the inside of the system became uniform, 0.43 ml of thioglycolic acid as a cocatalyst and 1.15 g of paratoluenesulfonic acid monohydrate as a catalyst were added. Then, heating was started by an oil bath equipped with a heater installed at the bottom of the container, and the reaction was carried out at 60 ° C. for about 5 hours.
After completion of the reaction, 18 ml of 4% aqueous sodium hydroxide solution was added to neutralize the catalyst. After the reaction solution was cooled to room temperature, it was put into a separating funnel together with about 2000 ml of methyl isobutyl ketone and washed 3 times with about 800 ml of deionized water. After that, the solvent and phenol were removed by distillation under reduced pressure, the phenol was completely removed by steam distillation, 1500 ml of chloroform was added to the residue, and the mixture was boiled for about 30 minutes and then cooled to room temperature. This is filtered to take out crystals, which are dried in a vacuum dryer (5 mmHg / 80 ° C., 6 hours) to give a polyhydric phenol compound (hereinafter referred to as compound A).
95.1 g was obtained. Yield 31.4% (hereinafter, simply referred to as the yield, when the weight in the case of reacting 4-fold mole of phenol with 2,6-diformyl-4-methylphenol is 100%). The softening point of compound A is 151-156.
C., the hydroxyl equivalent was 108 (hydroxyl value was 520).

The softening point was measured by a trace melting point measuring device (manufactured by Yanaco Instruments Development Laboratory Co., Ltd.) and visually observing the sample sandwiched between the glass plates on the heating stage with a 10 × magnifying glass. The measurement was performed. The hydroxyl value is JIS
The measurement was performed according to K 0070, and the hydroxyl equivalent was calculated from the result. Hydroxyl equivalent = {56.11 (molecular weight of potassium hydroxide) / hydroxyl value} × 1000.

Production Example 2 In a reaction vessel connected with a water separator connected with a stirrer, a reflux condenser, a mercury thermometer and a nitrogen gas inlet tube, 2,6-
Diformyl-4-methylphenol (33.16 g), phenol (342.22 g) and toluene (375 ml) were charged, and the mixture was stirred at room temperature under a nitrogen stream. When the system became uniform, 0.143 ml of thioglycolic acid as a cocatalyst and paratoluenesulfone as a catalyst. 0.384 g of acid monohydrate was added. Then, heating was started by an oil bath equipped with a heater installed in the lower part of the container, and the reaction was carried out for about 6 hours while removing azeotropic water under reflux. After completion of the reaction, heating was stopped and when the temperature reached around 80 ° C., 6.00 ml of 4% sodium hydroxide aqueous solution was added to neutralize the catalyst. After cooling the reaction solution to room temperature, about 2000 parts of methyl isobutyl ketone
Put it in a separating funnel together with ml and deionize water about 800 m.
Wash 3 times with 1. Then, the solvent and phenols were removed by vacuum distillation, and the phenols were completely removed by steam distillation. After crushing the resin obtained here with a crusher, a vacuum dryer (5 mmHg / 80 ° C, 6 hours)
Then, 98.5 g of a polyphenol compound (hereinafter referred to as compound B) was obtained (yield 97.6%). In addition, the softening point of the compound B is 105-1114 ° C., and the hydroxyl equivalent is 11
It was 4 (hydroxyl value was 493).

Production Example 3 The same procedure as in Production Example 2 was repeated except that 392.24 g of orthocresol was used in place of 342.22 g of phenol and the amount of toluene used was changed to 426 ml. 110.1 g of a dihydric phenol compound (hereinafter referred to as compound C) was obtained (yield 98.2%). In addition,
The content of pentanuclear compound of Compound C is 62.03%, and the softening point is 1.
10-117 ° C., hydroxyl equivalent 125 (hydroxyl value is 44
8).

Example 1 A reaction vessel (2000 ml) connected with a stirrer, a reflux condenser, a mercury thermometer, a nitrogen gas introducing tube and a decompressor was charged,
81.55 g of the compound A obtained in Production Example 1 and 448.63 g of epichlorohydrin were charged, heated to 55 ° C., 1.53 g of benzyltrimethylammonium chloride was added, and the mixture was reacted for 1 hour and 30 minutes. 48 to this
% Aqueous sodium hydroxide solution (80.0 g) was added dropwise over about 30 minutes, taking care not to let the temperature rise above 60 ° C. Then, the mixture was distilled at 60 ° C./150 mmHg and concentrated until no azeotropic water came out and the total amount became about 250 ml. It is cooled to room temperature and tetrahydrofuran 800
After adding in ml and stirring, the insoluble matter was removed by filtration, 1000 ml of methyl isobutyl ketone was added, and the mixture was washed 3 times with 600 ml of deionized water. This was distilled off under reduced pressure to remove unreacted epichlorohydrin with a solvent to obtain 101.6 g of an epoxy resin (hereinafter referred to as epoxy resin A) (yield 80.1%, epichlorohydrin reacted with all hydroxyl groups of compound A). If the weight is 100%). In addition,
Epoxy resin A had a softening point of 89-91 ° C and an epoxy equivalent of 185.

Example 2 Instead of the compound A obtained in Production Example 1 in Example 1,
The reaction was performed in the same manner as in Example 1 except that the compound B obtained in Production Example 2 was used to obtain 115.5 g of an epoxy resin (hereinafter referred to as the epoxy resin B) (yield 92.1%; (The weight when all the hydroxyl groups are reacted with epichlorohydrin is 100%). The softening point of the epoxy resin B was 98-101 ° C. and the epoxy equivalent was 222.

Example 3 In Example 1, 81.5 of the compound A obtained in Preparation Example 1 was used.
Instead of 5 g, 90.62 g of the compound C obtained in Production Example 3
The same reaction as in Example 1 was carried out to obtain 121.6 g of an epoxy resin (hereinafter referred to as epoxy resin C) (yield 90.3%, epichlorohydrin reacted with all hydroxyl groups of compound C). If the weight is 100%).
The softening point of the epoxy resin C was 97-100 ° C and the epoxy equivalent was 236.

Example 4 90 g of epoxy resin A and 60 g of novolac phenol resin (Barcam TD2121, manufactured by Dainippon Ink and Chemicals, Inc.) as a curing agent were premixed at 110 ° C. for 2 to 4 minutes, and then a curing accelerator. As triphenylphosphine 2
g, other ester-based wax (Hoechst, Wa
x OP) 2g, carbon black (Mitsubishi Kasei Co., Ltd.)
Manufactured by MA-100) (0.5 g) and silica (Tatsumori Co., Ltd., CRS-1101-01) (350 g) were added,
Using a mixing roll 6 × 12 inch (manufactured by Inoue Seisakusho Co., Ltd.), heating roll kneading was performed at 90 ° C. for 6 to 10 minutes. Then, pulverize and adjust the particle size with a compression molding machine (hydraulic molding machine, MF-O type, manufactured by Marushichi Iron Works Co., Ltd.)
It was compression molded under the conditions of 70 ° C., 280 kg / cm 2, and 4 minutes, and further cured at 175 ° C. for 8 hours to obtain a cured product.

Example 5 A cured product molded in the same manner as in Example 4 except that epoxy resin B was used instead of epoxy resin A in Example 4 was obtained.

Example 6 In Example 4, instead of 90 g of epoxy resin A,
Using 93 g of epoxy resin B, the amount of curing agent used is 57
A cured product formed in the same manner as in Example 4 except that g was replaced with g was obtained.

Comparative Example 1 In Example 4, instead of 90 g of the epoxy resin A,
Epoxy equivalent 205 cresol novolac type epoxy resin (YDCN 702P, Toto Kasei Co., Ltd.) 100
g was used, and the amount of the curing agent used was changed to 50 g to obtain a cured product molded in the same manner as in Example 4.

The molded cured products obtained in the examples and comparative examples were subjected to the following tests to measure various physical properties. The results are shown in Table 1.

(Hot plate gel time) The time (seconds) until the molding material gelled on the hot plate at 170 ° C. was measured.

(Volume resistivity) Disc (100 mmΦ × 2
mm) in the cured product at room temperature
JISK6911 using an ISTANCE METER 4329-A type (manufactured by Hewlett Packard)
(Unit: × 10 ¹⁵ Ωcm).

(Bending strength) Autograph DSS at room temperature
-2000 (manufactured by Shimadzu Corporation)
Measured according to K6911 (unit: kgf / mm
² ).

(Glass transition point) TMA-30 type (Co., Ltd.)
A temperature / linear expansion curve was measured using a device manufactured by Shimadzu Corporation, and the temperature at the bending point was taken as the glass transition point (° C).
(℃)

[0056]

[Table 1]

From the results shown in Table 1, the cured product of the epoxy resin composition of the present invention using the epoxy resins A to C is compared with the cured product of the epoxy resin composition using the conventional cresol novolac type epoxy resin. Have a high glass transition point (excellent heat resistance). Regarding other performances, it is recognized that they have equivalent or higher performances. In Table 1, * 1 represents a cresol novolac type epoxy resin (YDCN 702P, Toto Kasei Co., Ltd., epoxy equivalent 205).

Claims (3)

[Claims] 1. General formula (1): (In the formula, G is a glycidyl group, R ₁ is an alkyl group having 1 to 12 carbon atoms, R ₂ is a hydrogen atom, a hydroxy group or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 or 2. The epoxy resin represented by. 2. General formula (2): (In the formula, R ₁ represents an alkyl group having 1 to 12 carbon atoms, R ₂ represents a hydrogen atom, a hydroxy group or an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 or 2.) The method for producing an epoxy resin according to claim 1, wherein the polyhydric phenol compound is reacted with epihalohydrin. 3. An epoxy resin composition comprising the epoxy resin according to claim 1, a novolac-type phenol resin as a curing agent, and a curing accelerator.