JPH07268061A - Epoxy resin, epoxy resin composition, and cured item thereof - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin which gives a cured item excellent in heat resistance and toughness by reacting a specific epoxy resin with an epihalohydrin in the presence of dimethyl sulfoxide, etc. CONSTITUTION:The objective epoxy resin of formula II is obtd. by reacting a compd. of formula I with an epihalohydrin in the presence of dimethyl sulfoxide, a quaternary ammonium salt or 1, 3-dimethyl-2-imidazolidinone, and an alkali metal hydroxide. In those formulas (n) is a mean number and positive; R is H, a 1-8C alkyl, etc.; P and Q are each a halogen, etc.; G is glycidyl; and X is H or glycidyl provided 5-95% of all the X's are glycidyl. The epoxy resin of formula I is obtd. by, e.g. reacting phenolic hydroxyl groups of a compd. of formula III with an epihalohydrin and epoxidizing the reaction product.

Description

Detailed Description of the Invention

[0001]

The present invention has excellent heat resistance and water resistance,
Moreover, the present invention relates to an epoxy resin and an epoxy resin composition that give a cured product having a low dielectric constant, and a cured product thereof. The composition of the present invention is a laminate material, a sealing material, a molding material,
It is extremely useful for a wide range of applications such as casting materials, composite materials, paints, adhesives and resists.

[0002]

2. Description of the Related Art Epoxy resins, when cured with various curing agents, generally become cured products having excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc. It is used in a wide range of fields such as laminates, molding materials, and casting materials. Conventionally, liquid and solid bisphenol A type epoxy resins obtained by reacting bisphenol A with epichlorohydrin have been used as the most industrially used epoxy resins. Other liquid bisphenol A type epoxy resin to tetrabromobisphenol
A flame-retardant bromine-containing epoxy resin obtained by reacting the resin A is industrially used as a general-purpose epoxy resin.

[0003]

However, the general-purpose epoxy resin as described above has a drawback that the heat resistance of the cured product obtained by using the general-purpose epoxy resin decreases as the molecular weight increases. Further, when a polyfunctional epoxy resin such as an orthocresol novolac epoxy resin is added to a general-purpose epoxy resin, the heat resistance of the cured product is improved, but the water resistance is deteriorated. Further, in recent years, with the increase in the number of layers of printed wiring boards, low dielectric properties of resins have been required for the purpose of improving the signal speed. It is well known that a thermoplastic resin having a low dielectric constant is added as a means for satisfying this requirement, but when this method is used, there are drawbacks such as deterioration of heat resistance of the cured product.

[0004]

In view of these circumstances, the present inventors have earnestly studied for an epoxy resin that gives a cured product having excellent heat resistance and toughness, and as a result, the following specific epoxy resin was found to be the cured product. On the other hand, they have found that they impart excellent heat resistance, water resistance and low dielectric properties, and have completed the present invention.

That is, the present invention is based on the equation (1) (1)

[0006]

[Chemical 2]

(In the formula, n represents an average value and represents a positive number. R
Represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group, and each R may be the same or different from each other. P and Q are halogen atoms and have 1 to 8 carbon atoms
Represents an alkyl group or an aryl group of
Q may be the same as or different from each other. G represents a glycidyl group. X represents a hydrogen atom or a glycidyl group, and each X may be the same or different from each other, but 5% or more and 95% or less of all Xs are glycidyl groups. ) Epoxy resin represented by

(2) An epoxy resin composition containing an epoxy resin, a curing agent, and optionally a curing accelerator, wherein the epoxy resin composition contains the epoxy resin of the formula (1). ,
(3) A cured product obtained by curing the epoxy resin composition according to (2) above.

The epoxy resin represented by the formula (1) is represented by, for example, the formula (2)

[0010]

[Chemical 3]

(In the formula, n, R, P, Q and G have the same meanings as in formula (1).)

It can be obtained by reacting the compound represented by ## STR1 ## with epihalohydrin in the coexistence of dimethyl sulfoxide, a quaternary ammonium salt or 1,3-dimethyl-2-imidazolidinone and an alkali metal hydroxide. . The present inventors have found that the alcoholic hydroxyl group of the epoxy resin represented by the formula (2) is more reactive than that of general alcohols, and for example, dimethyl sulfoxide, quaternary ammonium or 1,3-dimethyl-2- Surprisingly, the coexistence of imidazolidinone and alkali metal hydroxide surprisingly causes the reaction between the alcoholic hydroxyl group and the epoxy group existing in the system to react only with the epoxy group derived from epihalohydrin newly added as a raw material. It was found that the alcoholic hydroxyl groups of the epoxy resin represented by the formula (2) can be epoxidized to a desired ratio by selectively performing the above process and adjusting the amount of the alkali metal hydroxide.

The details of the present invention will be described below. Examples of the method for obtaining the epoxy resin represented by the formula (2) used as a raw material in the present invention include the formula (3)

[0014]

[Chemical 4]

(In the formula, R, P and Q have the same meanings as in formula (1).)

A method of epoxidizing the phenolic hydroxyl group of the compound represented by the formula (1) with epihalohydrin is mentioned.

The compound represented by the formula (3) is described in JP-A-58 / 58.
In addition to the methods described in JP-A-121230, JP-A-58-121231, JP-A-63-303939, etc., those obtained by any known method can be used. That is, as a general method for producing the compound represented by the formula (3), diisopropenylbenzene, bis (α-hydroxyisopropyl) benzene, 1-isopropenyl-2-α-hydroxyisopropylbenzene,
The reaction of dialkenylbenzenes or dihydroxybenzenes such as 1-isopropenyl-4-α-hydroxyisopropylbenzene and aromatic nucleus-substituted derivatives thereof with phenols with an acid catalyst is exemplified. Not as long.

The term "phenols" as used herein refers to compounds having at least one phenolic hydroxyl group, examples of which include phenol, cresol, ethylphenol, n-propylphenol, isobutylphenol, t-butylphenol, octylphenol, nonylphenol, xylenol and methyl. Various kinds of alkylphenols such as butylphenol and di-t-butylphenol o
Representative examples are-, m-, p-isomers, or various o-, m-, p-isomers of vinylphenol, allylphenol, propenylphenol, ethynylphenol, cyclopentylphenol, cyclohexylphenol, cyclohexylcresol and the like. Included are substituted phenols such as cycloalkylphenols.

Among the phenols, 2,6-xylenol, 2 and 6 are more preferable for lowering the dielectric constant.
-Butyl-5-methylphenol, 2-butyl-4-methylphenol, 2,4-dibutylphenol, 2,4
-Di (t-amyl) phenol, 2-cyclohexyl-
5-methylphenol, 2-t-butylphenol, 2
Examples thereof include-(t-amyl) phenol and 2-cyclohexylphenol.

When the condensation reaction is carried out, the amount of phenols used is preferably 2 to 20 mol, particularly preferably 3 to 10 mol, per 1 mol of dialkenylbenzenes or dihydroxyalkylbenzenes.

In the above condensation reaction, it is preferable to use an acid catalyst, and various acid catalysts can be used, but hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, boron trifluoride,
Anhydrous aluminum chloride, zinc chloride and the like are preferable, and hydrochloric acid and p-toluenesulfonic acid are particularly preferable. The amount of these acid catalysts used is not particularly limited, but can be selected within a range of 0.01 to 50 times the molar amount of the dialkenylbenzenes or dihydroxyalkylbenzenes used.

After the condensation reaction, the acid catalyst is removed by dissolving in an organic solvent and neutralizing or washing with water. Specific examples of the organic solvent that can be used in this case include toluene, xylene, and methyl isobutyl ketone, with toluene being preferred. The amount of the organic solvent used is preferably 50 to 300% by weight with respect to the total weight of the raw materials charged, and particularly 100 to 25
0% by weight is preferred.

Next, the oil layer is concentrated under heating and reduced pressure, and unreacted phenols and organic solvent are removed to obtain a glassy solid. The obtained glassy solid is dissolved in an organic solvent such as toluene, xylene, or methyl isobutyl ketone, a poor solvent such as n-hexane or n-heptane is added, and the mixture is recrystallized to be represented by the formula (3). The compound can be obtained.

As a method for obtaining the epoxy resin represented by the formula (2), a known method can be adopted. For example, by adding an alkali metal hydroxide to a dissolved mixture of a compound represented by the formula (3) and excess epihalohydrin, or by reacting at a temperature of 20 to 120 ° C. while adding the alkali metal hydroxide, the formula (4)

[0025]

[Chemical 5]

(In the formula, R, P, Q and G have the same meanings as in formula (1).)

After obtaining the low molecular weight epoxy resin represented by the formula (3), the compound represented by the formula (3) and the temperature between 70 and 200 ° C. are further melted or in a solvent in the presence of a basic catalyst. It can be obtained by reacting with.

In the reaction for obtaining the epoxy resin represented by the formula (4), an aqueous solution of the alkali metal hydroxide may be used. In that case, an aqueous solution of the alkali metal hydroxide is continuously added to the reaction system. Water and epihalohydrin are continuously distilled off under reduced pressure or normal pressure while being added to
Further, a method may be adopted in which liquid separation is carried out, water is removed, and epihalohydrin is continuously returned to the reaction system.

Further, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide or trimethylbenzylammonium chloride is added as a catalyst to a dissolved mixture of the compound represented by the formula (3) and epihalohydrin, and the mixture is added at 50 to 150 ° C. The solid or aqueous solution of an alkali metal hydroxide is added to the halohydrin ether compound obtained by the reaction in step 1, and the mixture is added again to 20 to 120.
A method in which the reaction is carried out at a temperature of ° C. and dehydrohalogenation (ring closure) is also possible.

Usually, the amount of epihalohydrin used in these reactions is usually 1 to 20 mol, preferably 1.5 to 10 mol, based on 1 equivalent of the hydroxyl group of the compound represented by the formula (3).
It is 10 mol. The amount of the alkali metal hydroxide used is 0.8 to 1 equivalent of the hydroxyl group of the compound represented by the formula (3).
It is 1.5 mol, preferably 0.9 to 1.1 mol. In order to allow the reaction to proceed smoothly, it is preferable to carry out the reaction by adding alcohols such as methanol and ethanol, as well as an aprotic polar solvent such as dimethyl sulfone and dimethyl sulfoxide.

The epoxy resin represented by the formula (4) can be obtained by washing the reaction products of these epoxidation reactions with or without washing with water under reduced pressure with heating to remove epihalohydrin and other added solvents. it can.

The low molecular weight epoxy resin represented by the formula (4) is reacted with the compound represented by the formula (3) to obtain the compound represented by the formula (2).
In the reaction for obtaining the epoxy resin represented by, the charging ratio of each component is 0.05 to 0.9 equivalent of the compound represented by the formula (3) with respect to 1 equivalent of the epoxy resin represented by the formula (4). It is particularly preferably 0.1 to 0.85 equivalent.

The basic catalyst includes, for example, triphenylphosphine, sodium hydroxide, quaternary ammonium salt, imidazoles, etc., and the amount thereof is used with respect to 1 equivalent of the epoxy resin represented by the formula (4). 0.00
1 to 1.0% by weight is preferable, and particularly 0.005 to 0.5
Weight percent is preferred. When a solvent is used, methyl isobutyl ketone, toluene, etc. may be mentioned.

The reaction between the alcoholic hydroxyl group of the epoxy resin represented by the formula (2) and epihalohydrin is carried out by the coexistence of dimethyl sulfoxide or a quaternary ammonium salt or 1,3-dimethyl-2-imidazolidinone and an alkali metal hydroxide. It can be carried out by adjusting the amount of the alkali metal hydroxide below. At that time, alcohols such as methanol and ethanol, aromatic hydrocarbons such as toluene and xylene, ketones such as methyl isobutyl ketone and methyl ethyl ketone, and cyclic and ether compounds such as tetrahydrofuran may be used together as a solvent.

The amount of dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone used is preferably 5 to 300% by weight based on the compound represented by the formula (2). When it exceeds 300% by weight with respect to the compound represented by the formula (2), the effect of increasing the amount is almost lost and the volume efficiency is deteriorated, which is not preferable.

Examples of the quaternary ammonium salt include tetramethylammonium chloride, tetramethylammonium bromide, trimethylammonium chloride and the like. The amount used is 1 equivalent of the hydroxyl group to be epoxidized of the compound represented by the formula (2). 0.3 to 50 g is preferable. If the amount of the hydroxyl group to be epoxidized is less than 0.3 g based on 1 equivalent, the reaction between the hydroxyl group of the compound represented by the formula (2) and epihalohydrin is delayed and a long-time reaction is required, which is not preferable. If the amount of the hydroxyl group to be epoxidized is more than 50 g per 1 equivalent, the effect of increasing the amount is almost lost, but the cost becomes high, which is not preferable.

The amount of epihalohydrin used may be equal to or more than 1 equivalent of the hydroxyl group to be epoxidized in the compound represented by the formula (2). However, if it exceeds 20 equivalents with respect to 1 equivalent of the hydroxyl group to be epoxidized, the effect of increasing the amount is almost lost and the volume efficiency is deteriorated, which is not preferable.

As the alkali metal hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide and the like can be used, but sodium hydroxide is preferred. The amount of the alkali metal hydroxide used is 1 with respect to 1 equivalent of the hydroxyl group to be epoxidized in the compound represented by the formula (2).
It suffices to use ~ 2 equivalents. The alkali metal hydroxide may be solid or aqueous solution. When an aqueous solution is used, the reaction can be carried out during the reaction while distilling the water in the reaction system out of the reaction system under normal pressure or reduced pressure.

The reaction temperature is preferably 20 to 100 ° C. If the reaction temperature is lower than 20 ° C, the reaction becomes slow and a long-time reaction is required. When the reaction temperature exceeds 100 ° C., many side reactions occur, which is not preferable.

The epoxy resin composition of the present invention can be obtained by adding the curing agent and, if necessary, a curing accelerator and the like to the epoxy resin of the present invention alone or in combination with another epoxy resin. The curing agent that can be used in the present invention is an amine compound, an acid anhydride compound, an amide compound, a phenol compound or the like. As a specific example,
Diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone,
Polyamide resin synthesized from isophoronediamine, dicyandiamide, dimer of linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, Examples thereof include methyl nadic acid anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolac, and modified products thereof, imidazole, BF ₃ -amine complex, guanidine derivative and the like. These curing agents may be used alone or in combination of two or more.

The amount of these curing agents used is preferably 0.7 to 1.2 equivalents based on the epoxy group. If the amount is less than 0.7 equivalents or more than 1.2 equivalents with respect to the epoxy groups, curing may be incomplete and good cured physical properties may not be obtained.

When using the above-mentioned curing agent, a curing accelerator may be used in combination. Examples of the curing accelerator include imidazoles, tertiary amines, phenols, metal compounds and the like. Furthermore, various compounding agents such as inorganic or organic fillers can be added as required. The amount of these curing accelerators used is 100% epoxy resin.
0.1 to 5.0 parts by weight is preferable with respect to parts by weight.

The epoxy resin composition of the present invention can be easily made into a cured product by the same method as a conventionally known method. For example, the epoxy resin composition of the present invention and a curing agent, a filler, and other additives are sufficiently mixed with an extruder, a kneader, a roll, etc., if necessary, until a uniform mixture is obtained. Then, the epoxy resin composition is melted, molded using a casting or transfer molding machine, and then heated to 80 to 200 ° C. to obtain a cured product.

Further, the resin composition of the present invention is diluted and dissolved in a solvent to prepare glass fiber, carbon fiber, polyester fiber,
It is also possible to obtain a cured product by hot pressing a prepreg obtained by impregnating a base material such as polyamide fiber, alumina fiber or paper and heating and drying.

Specific examples of the diluting solvent that can be used at this time are methyl ethyl ketone, acetone, methyl isobutyl ketone and the like. The amount of the diluting solvent used is usually 10 to 70% by weight based on the total weight of the epoxy resin composition of the present invention and the diluting solvent. %, Preferably 15 to 65% by weight.

The cured product thus obtained is excellent in heat resistance and water resistance and has a property of low dielectric property, so that it can be used in a wide range of fields where heat resistance, water resistance and low dielectric property are required. Specifically, it is useful as any electric / electronic material such as a laminated plate, a sealing material, and an insulating material.
It can also be used in the field of molding materials and composite materials.

[0047]

EXAMPLES The present invention will now be described in detail with reference to Examples and Comparative Examples. In the following, all parts are parts by weight unless otherwise specified. The conditions for measuring the glass transition temperature and the water absorption are as follows. Glass transition temperature Thermomechanical measuring device (TMA): Vacuum Riko TM-7000 Temperature rising rate: 2 ° C / min Water absorption rate Test piece (cured product): Diameter 50 mm Thickness 3 mm Disc 100 ° C After boiling in water for 20 hours Weight increase (% by weight) Dielectric constant test piece (cured product): Diameter 50 mm Thickness 3 mm Disc JIS K-6911 Dielectric loss measuring device TR-10C (manufactured by Ando Electric Co., Ltd.) Frequency 1 KHz
Measured by

Example 1 820 parts (5 mol) of 2-t-butyl-5-methylphenol and bis (α-hydroxyisopropyl) benzene 58.2 were placed in a flask equipped with a thermometer, a dropping funnel, a condenser and a stirrer. (0.3 mol) and 1000 parts of concentrated hydrochloric acid were charged and reacted at 60 ° C. for 1 hour. After further charging 58.2 parts of bis (α-hydroxyisopropyl) benzene and holding at 60 ° C. for 1 hour, 77.6 parts of bis (α-hydroxyisopropyl) benzene was charged again and kept at 60 ° C. for 7 hours to carry out the reaction. It was completed. After the reaction, toluene 2000
After adding a portion to remove the concentrated hydrochloric acid layer, the mixture was neutralized with a 10% aqueous sodium hydroxide solution and further washed with water. After that, the solvent and unreacted components were removed from the oil layer using a rotary evaporator under heating and reduced pressure of 180 ° C. and 5 mmHg to obtain a glassy solid. Then, after recrystallizing in toluene / n-heptane, the crystals were washed with cold toluene and dried under reduced pressure to obtain 247 parts of a compound represented by the following formula (5).

[0049]

[Chemical 6]

Next, 122 parts (0.25 mol) of the compound obtained in the above reaction, 231 parts of epichlorohydrin and 116 parts of dimethyl sulfoxide were charged and dissolved in a flask equipped with a thermometer, a cooling tube and a stirrer while purging with nitrogen gas. Let The mixture was further heated to 70 ° C., 20 parts of flaky sodium hydroxide was added portionwise over 100 minutes, and then the mixture was further reacted at 70 ° C. for 3 hours. After completion of the reaction, excess epichlorohydrin and dimethylsulfoxide were distilled off under reduced pressure with heating at 130 ° C. and 5 mmHg using a rotary evaporator, and 300 parts of methyl isobutyl ketone was added to the residue and dissolved.

Further, a solution of this reaction product in methyl isobutyl ketone was heated to 70 ° C., 6.7 parts of a 30 wt% sodium hydroxide aqueous solution was added, and the reaction was carried out for 1 hour. did. Furthermore, the water layer is separated and removed
Methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure using a rotary evaporator to obtain 139 parts of an epoxy resin represented by the following formula (6). The obtained epoxy resin has a softening point of 62.3 ° C. and an epoxy equivalent of 321 g / e.
It was q.

[0052]

[Chemical 7]

(In the formula, G represents a glycidyl group.) 128 parts of the epoxy resin represented by the formula (6) obtained in the above steps, 33.6 parts of the compound represented by the formula (5), and methyl 80 parts of isobutyl ketone was charged into a flask and dissolved by stirring, 0.1 part of triphenylphosphine was added, methyl isobutyl ketone was distilled off under reduced pressure at 120 ° C. under stirring, and the reaction was further carried out at 150 ° C. for 2 hours to obtain the following formula. Epoxy equivalent represented by (7) 621 g / eq, softening point 75.8
161 parts of epoxy resin having a temperature of 0 ° C. was obtained.

[0054]

[Chemical 8]

(In the formula, n is 1.19 (average value), and G
Represents a glycidyl group. ) Further, 285 parts of epichlorohydrin was added to the reaction system and dissolved by stirring, and then 1 part of tetramethylammonium chloride was added at 40 ° C under stirring. Thereafter, 8.0 parts of flaky sodium hydroxide was added, and the reaction was further performed for 3 hours. After the reaction was completed, 150 parts of water was added and the mixture was washed with water. After hot-water separation, unreacted epichlorohydrin was distilled and recovered from the oil layer under reduced pressure to obtain 160 parts of an epoxy resin (A) represented by the following formula (8).

[0056]

[Chemical 9]

(In the formula, n is 1.19 (average value), and G
And X have the same meanings as in the above formula (1). ) The epoxy equivalent of the obtained epoxy resin is 388 g / e.
q and the softening point were 68.5 degreeC. In the obtained epoxy resin, 70% of X in the formula (8) was an epoxy group calculated from the epoxy equivalent.

Example 2 Epoxy equivalent of 496 g / same as in Example 1 except that the amount of flaky sodium hydroxide used was changed to 5.5 parts.
Thus, 160 parts of an epoxy resin (B) having an eq and a softening point of 71.2 ° C. was obtained. In the obtained epoxy resin, when calculated from the epoxy equivalent, 48% of X in the formula (8) was an epoxy group.

Examples 3 to 4, Comparative Example 1 Epoxy resins (A) to (B) obtained in Examples 1 and 2,
For comparison, bisphenol A type epoxy resin (Epomic R-301, epoxy equivalent 468 g / eq, softening point ° C, manufactured by Mitsui Petrochemical Co., Ltd.) was used diaminodiphenylmethane (DDM) as a curing agent, and the composition and parts by weight shown in Table 1 were used. And knead with a roll for 15 minutes at 70 ° C.
Transfer molding at 0 ℃ for 180 seconds, then 16
A test piece was prepared by curing at 0 ° C. for 2 hours and further at 180 ° C. for 8 hours, and the glass transition temperature, water absorption rate and dielectric constant were measured. The results are shown in Table 1.

[0060]

[Table 1] Table 1 Examples Comparative Examples 3 4 1 Epoxy resin (A) 100 Epoxy resin (B) 100 Epomic R-301 100 Epoxy equivalent (g / eq) 388 496 468 DDM 12.8 10.0 10.6 Glass transition temperature (° C ) 156 148 138 Water absorption (%) 1.42 1.54 1.85 Dielectric constant (ε) 3.15 3.08 3.89

Example 5 A flask equipped with a thermometer, a dropping funnel, a condenser and a stirrer was charged with 2,6-xylenol (5 mol) and bis (α-).
Hydroxyisopropyl) benzene 58.2 parts (0.3
Mol) and 1000 parts of concentrated hydrochloric acid were charged and reacted at 60 ° C. for 1 hour. After further charging 58.2 parts of bis (α-hydroxyisopropyl) benzene and holding at 60 ° C. for 1 hour,
Again bis (α-hydroxyisopropyl) benzene 7
7.6 parts was charged and the reaction was completed by holding at 60 ° C. for 7 hours. After the reaction, 2000 parts of toluene was added to remove the concentrated hydrochloric acid layer, and the mixture was neutralized with a 10% sodium hydroxide aqueous solution and further washed with water. After that, the solvent and unreacted components were removed from the oil layer using a rotary evaporator under heating and reduced pressure of 180 ° C. and 5 mmHg to obtain a glassy solid. Then, the crystals were recrystallized in toluene / n-heptane, washed with cold toluene, and dried under reduced pressure to obtain 306 parts of a compound represented by the following formula (9).

[0062]

[Chemical 10]

Next, 201 parts (0.5 mol) of the compound obtained in the above reaction, 463 parts of epichlorohydrin and 231 parts of dimethyl sulfoxide were charged into a flask equipped with a thermometer, a condenser and a stirrer while purging with nitrogen gas. Let The mixture was further heated to 70 ° C., 20 parts of flaky sodium hydroxide was added portionwise over 100 minutes, and then the mixture was further reacted at 70 ° C. for 3 hours. After completion of the reaction, excess epichlorohydrin and dimethyl sulfoxide were distilled off at 130 ° C. under heating and reduced pressure of 5 mmHg using a rotary evaporator, and 514 parts of methyl isobutyl ketone was added and dissolved.

Further, this methyl isobutyl ketone solution was heated to 70 ° C., 13.3 parts of a 30 wt% sodium hydroxide aqueous solution was added, and the mixture was reacted for 1 hour, and then washed with water repeatedly to make the pH neutral. Further, the aqueous layer was separated and removed, and methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure using a rotary evaporator to obtain 242 parts of an epoxy resin represented by the following formula (10). The obtained epoxy resin had a softening point of 53.2 ° C and an epoxy equivalent of 274 g / eq.

[0065]

[Chemical 11]

(In the formula, G represents a glycidyl group.) 110 parts of the epoxy resin represented by the formula (10) obtained in the above steps, 32.2 parts of the compound represented by the formula (9), and methyl 71.1 parts of isobutyl ketone was charged into a flask and dissolved by stirring, then 0.1 part of triphenylphosphine was added, methyl isobutyl ketone was distilled off under reduced pressure at 120 ° C. under stirring, and further reacted at 150 ° C. for 2 hours. 142 parts of an epoxy resin represented by the following formula (11) having an epoxy equivalent of 591 g / eq and a softening point of 69.2 ° C. was obtained.

[0067]

[Chemical 12]

(Where n is 1.46 (average value), and G
Represents a glycidyl group. ) Further, 324 parts of epichlorohydrin was added to the reaction system and dissolved by stirring, and then 1 part of tetramethylammonium chloride was added at 40 ° C. under stirring. After that, 8.4 parts of flaky sodium hydroxide was added, and the reaction was further performed for 3 hours. After the reaction was completed, 150 parts of water was added and the mixture was washed with water. After hot-water separation, unreacted epichlorohydrin was distilled and recovered from the oil layer under reduced pressure to obtain 144 parts of an epoxy resin (C) represented by the following formula (12).

[0069]

[Chemical 13]

(Where n is 1.46 (average value), and G
And X have the same meanings as in the above formula (1). ) The epoxy equivalent of the obtained epoxy resin is 419 g / e.
q and the softening point were 59.3 degreeC. The obtained epoxy resin has X in the formula (12) when calculated from the epoxy equivalent.
Of these, 65% were epoxy groups.

Example 6 Epoxy equivalent of 463 g / same as in Example 1 except that the amount of flaky sodium hydroxide used was changed to 5.6 parts.
139 parts of an epoxy resin (D) having an eq and a softening point of 63.2 ° C. were obtained. In the obtained epoxy resin, 43% of X in the formula (12) was an epoxy group when calculated from the epoxy equivalent.

Examples 7-8, Comparative Example 2 Epoxy resins (C)-(D) obtained in Examples 5-6,
For comparison, bisphenol A type epoxy resin (Epomic R-301, epoxy equivalent 468 g / eq, softening point ° C, manufactured by Mitsui Petrochemical Co., Ltd.) was used as a curing agent, and phenol novolac (PN: manufactured by Nippon Kayaku Co., Ltd.) was used. The composition and parts by weight shown in Table 2 were blended, kneaded with a roll at 70 ° C. for 15 minutes, transfer molded at 150 ° C. for 180 seconds, and then cured at 160 ° C. for 2 hours and further at 180 ° C. for 8 hours. A test piece was prepared and the glass transition temperature, water absorption and dielectric constant were measured.

The results are shown in Table 2. The transfer molding conditions and post-cure conditions are the same as in Examples 3 to 4 and Comparative Example 1.

[0074]

Table 2 Examples Examples Examples Comparative Examples 7 8 2 Epoxy resin (C) 100 Epoxy resin (D) 100 Epomic R-301 100 Epoxy equivalent (g / eq) 419 463 468 Curing agent (PN) 25.3 22.9 22.6 Curing accelerator (2E4MZ) 1 1 1 Glass transition temperature (℃) 135 130 110 Water absorption rate (%) 0.58 0.63 0.81 Dielectric constant (ε) 2.9 3.0 3.5

[0075]

As is clear from Tables 1 and 2, the epoxy resin of the present invention has a heat resistance and a water resistance which are higher than those of conventional general-purpose epoxy resins. It has excellent properties and also has the characteristics of low dielectric constant. That is, the epoxy resin of the present invention can provide a cured product having excellent heat resistance and water resistance and a low dielectric constant, and can be used as a molding material, a casting material, a laminating material, a paint, an adhesive,
It is extremely useful for a wide range of applications such as resists.

Claims (3)

[Claims] 1. A formula (1): (In the formula, n represents an average value and represents a positive number. R is a hydrogen atom,
Each R represents an alkyl group having 1 to 8 carbon atoms or an aryl group, and each R may be the same or different. P and Q represent any one of a halogen atom, an alkyl group having 1 to 8 carbon atoms and an aryl group, and each P and Q may be the same or different from each other. G represents a glycidyl group. X represents a hydrogen atom or a glycidyl group, and each X may be the same as or different from each other, but 5% or more and 95% or less of all Xs are glycidyl groups. ) Epoxy resin represented by. 2. An epoxy resin composition containing an epoxy resin, a curing agent, and optionally a curing accelerator, wherein the epoxy resin composition according to claim 1 is contained as the epoxy resin component. 3. A cured product obtained by curing the epoxy resin composition according to claim 2.