JPH11343333A - Epoxy resin composition and its cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition which can give a cured product having low hygroscopicity, excellent electrical properties, and high hydrolysis resistance. SOLUTION: This composition contains an epoxy resin which contains at least two epoxy groups and in which the hydrogen atom of the hydroxyl group of a CH2 CH(OH) structure resulting from the ring opening of an epoxy group is replaced by a hydrophobic non-reactive silyl group the silicon atom of which is bonded to aliphatic, aromatic, and/or heterocyclic groups and a 2-allylphenol/ formaldehyde polycondensate (of an average degree of polymerization of below 3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of producing and using an epoxy resin composition mainly used as an electric / electronic device component material, for example, a semiconductor sealing material. More specifically, an epoxy resin composition which gives a cured product having low hygroscopicity and excellent electrical properties, and a cured product obtained by curing the epoxy resin composition, which has low hygroscopicity and excellent electrical properties, and has high hydrolysis resistance. Belongs to the technical field used.

[0002]

2. Description of the Related Art Epoxy resin compositions have been used in various applications in the electric and electronic fields because of their excellent electrical properties such as electrical insulation, adhesiveness, and mechanical strength.

However, due to recent technological innovations, high precision and high integration of electric and electronic parts are progressing, and accordingly, various kinds of epoxy resin compositions used as sealing agents for those parts are required. The characteristics have been advanced, and under such circumstances,
At present, strict evaluation of epoxy resin compositions is performed by various test methods.

[0004] Usually, an epoxy resin composition is used in combination with a curing agent due to demands for lowering viscosity and improving properties. The curing agent is appropriately selected according to the use and composition of the epoxy resin composition, but various properties of the composition and the cured product thereof vary greatly depending on the type of the curing agent.

[0005] Representative examples of curing agents that have been often used include amine-based curing agents, acid anhydride-based curing agents, and phenol-based curing agents.

When an amine-based curing agent is used, there are usually problems such as poor storage stability of the epoxy resin composition, short pot life after production, and irritating odor.

In addition, when an acid anhydride-based curing agent is used, the epoxy resin composition has a high hygroscopic property, and the cured product has poor water resistance, electrical insulation, hydrolysis resistance and the like. Also, in a pressure cooker test (PCT test, the same applies hereinafter) performed under high-temperature and high-pressure conditions, the cured product is significantly deteriorated due to hydrolysis.

[0008] On the other hand, when a phenolic curing agent is used, the cured product has the feature that the hydrolysis resistance is extremely high, and an epoxy resin composition having a relatively long pot life can be obtained. On the other hand, on the other hand, the cured product inherently contains a large amount of hydroxyl groups, resulting in high hygroscopicity, resulting in a decrease in electric properties due to water absorption, and also in poor performance of electric and electronic parts. There is.

As a method for improving the above-mentioned problems of the hygroscopicity and the deterioration of the electric characteristics, a method of reducing the hygroscopicity of the epoxy resin as a main component has been attempted. A silylated epoxy resin is known as one of such low hygroscopic epoxy resins. This silylated epoxy resin has a structure in which a hydroxyl group present in a conventionally known epoxy resin is blocked with a hydrophobic silyl group, has a small hygroscopic property of itself, and reduces moisture contained in the composition. effective.
For details such as the method for producing a silylated epoxy resin, see JP-A-8-
No. 245749.

[0010]

However, even when the epoxy resin, which is the main component of the epoxy resin composition, is made into a silylated epoxy resin to reduce the hygroscopicity, the composition is derived from the curing agent used in combination. However, it still cannot solve the problem of hygroscopicity of the epoxy resin composition, and still causes problems such as a decrease in water resistance and electrical properties of the epoxy resin composition, and further, a poor performance of parts caused by the deterioration.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has an epoxy resin composition having a long pot life and a low hygroscopic property, and a hygroscopic property obtained by thermosetting the same. The object of the present invention is to provide a cured product having a low resistance, high hydrolysis resistance and excellent electrical properties.

That is, according to the present invention, the hydroxyl group in the —CH ₂ —CH (OH) — structure formed by ring opening of the epoxy group (A) is an aliphatic group, an aromatic group and / or a heterocyclic group. Is blocked with a hydrophobic non-reactive silyl group bonded to a silicon atom and contains two or more epoxy groups, and (B) a 2-allylphenol-formaldehyde polycondensate (average degree of polymerization) 3) and a cured product obtained by thermally curing the epoxy resin composition according to claim 1 (claim 2).

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin composition of the present invention comprises:
—CH ₂ —CH (OH) formed by ring opening of the epoxy group
An epoxy resin in which a hydroxyl group in the structure is blocked with a hydrophobic non-reactive silyl group R in which an aliphatic group, an aromatic group and / or a heterocyclic group are bonded to a silicon atom (hereinafter also referred to as R group). Composition containing (A) (hereinafter also referred to as silylated epoxy resin (A) or epoxy resin (A)) and 2-allylphenol-formaldehyde polycondensate (B) (hereinafter also referred to as phenol resin (B)) Things.

Although the silylated epoxy resin (A) itself has low hygroscopicity, the use of a phenolic resin (B) as a curing agent has a remarkable effect that the water absorption of the cured product is further significantly reduced. be able to. Even if a phenolic curing agent is used as a curing agent for the silylated epoxy resin (A), such a remarkable effect can be obtained in a combination other than the combination with the phenolic resin (B). The remarkable effect is a unique effect obtained by the combination of the silylated epoxy resin (A) and the phenol resin (B).

The hydroxyl group in the —CH ₂ —CH (OH) — structure formed by ring opening of the epoxy group of the silylated epoxy resin (A) is an aliphatic group, an aromatic group and / or a heterocyclic group. Embedded image with a hydrophobic non-reactive silyl group R bonded to a silicon atom has a general formula (1):

[0016]

Embedded image

## EQU1 ##

The hydrophobicity in the hydrophobic non-reactive silyl group R is defined as an aliphatic group, an aromatic group and / or a heterocyclic group bonded to a silicon atom forming the R group.
It does not contain hydrophilic groups such as amino group, carboxylic acid group, mercapto group, thiocarboxylic acid group, polyether chain, sulfonyl group, cyano group and nitro group, and has low hydrophilicity as a whole R group (polarity is low). Lower). Since the R group is hydrophobic, a hydroxyl group normally present in the epoxy resin can be eliminated, and the hygroscopicity of the epoxy resin can be reduced.

The non-reactivity of the non-reactive silyl group R means a hydroxyl group, an amino group, or an aliphatic group, an aromatic group, and / or a heterocyclic group bonded to a silicon atom forming the R group. , A carboxyl group, a (meth) acryloyl group, a mercapto group, a thiocarboxylic acid group, an epoxy group, an isocyanate group, or any other reactive group.
It means that the group is stable without reacting with an epoxy group, moisture, a curing agent, a curing accelerator, a filler and the like at 130 ° C. for 5 hours or more or at 60 ° C. for 1 month or more. Since the R group is non-reactive, heat kneading is possible, and a stable and workable epoxy resin composition can be obtained.

Examples of the aliphatic group bonded to the silicon atom forming the R group include a chain or cyclic alkyl group and alkenyl group. The number of carbon atoms of the aliphatic group is not particularly limited, and is usually preferably 1 to 22.

Specific examples of the aliphatic group include those having 1 carbon atom such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, pentyl group and hexyl group.
Alkyl groups having from 1 to 22 carbon atoms such as vinyl, propenyl, allyl, isopropenyl, butenyl, and pentenyl.
Examples thereof include cyclic aliphatic groups having 3 to 10 carbon atoms such as 22 alkenyl groups, cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, cyclohexenyl groups, and bridged cyclic aliphatic groups.

Examples of the aromatic group bonded to the silicon atom forming the R group include an aryl group and an aralkyl group having a formula weight of 77 to 250.

Specific examples of the aromatic group include phenyl, tolyl, xylyl, mesityl, methoxyphenyl, cumenyl, benzyl, methylbenzyl, methoxybenzyl, phenylethyl and diphenylmethyl. Group, trityl group, styryl group, cinnamyl group, naphthyl group, anthryl group, phenanthryl group and the like.

Further, specific examples of the heterocyclic group bonded to the silicon atom forming the R group include a furyl group, a furfuryl group, a thienyl group, a pyrrolyl group, and a pyridyl group.

Among the substituents bonded to the silicon atom forming the R group, those which do not contain a hetero atom are preferable because they can effectively realize the hydrophobicity of the obtained resin composition. Further, the substituent is preferably smaller (for example, a methyl group, an ethyl group, or the like) from the viewpoint that a resin composition having a low viscosity can be obtained.

Specific examples of the non-reactive silyl group R include, for example, trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, trihexylsilyl, tribenzylsilyl, triphenylsilyl, ethyldimethylsilyl. Silyl group, n-propyldimethylsilyl group, isopropyldimethylsilyl group, tert
-Butyldimethylsilyl group, vinyldimethylsilyl group,
Allyldimethylsilyl group, phenyldimethylsilyl group,
Examples include diphenylvinylsilyl, cyclohexyldimethylsilyl, benzyldimethylsilyl, diphenylmethylsilyl, tert-butyldiphenylsilyl, tolyldimethylsilyl, furyldimethylsilyl, and pyridyldimethylsilyl. These may be used alone or in combination of two or more. Among these, trimethylsilyl group, triethylsilyl group, tripropylsilyl group, tributylsilyl group, ethyldimethylsilyl group, n-propyldimethylsilyl group,
An isopropyldimethylsilyl group is preferable from the viewpoint that a resin composition having a good balance between the hydrophobicity and viscosity of the resin composition can be obtained, and a trimethylsilyl group and a triethylsilyl group are particularly preferable.

The epoxy resin (A) has two or more, preferably two, epoxy groups in the molecule. A single epoxy group cannot form a crosslinked structure. Further, the upper limit of the number of epoxy groups in the molecule is preferably four, and more preferably three. When the number is five or more, the molecular weight of the epoxy resin (A) increases, the viscosity tends to increase, and the water absorption of the obtained cured product tends to increase.

The number average molecular weight of the epoxy resin (A) is not particularly limited, and usually 350 to 5000 is preferably used. However, when a liquid epoxy resin composition is obtained, the number average molecular weight is 700 or less. Further, those having a viscosity of 560 or less are preferable because a composition having a relatively low viscosity and a high hydrophobicity can be obtained.

The epoxy equivalent of the epoxy resin (A) is not particularly limited, but usually 170 to 2500 is preferably used. In general, as the epoxy equivalent becomes larger, the viscosity of the composition is less likely to decrease even when a liquid curing agent is used because the compounding ratio of the curing agent used in combination is small,
As the epoxy equivalent becomes smaller, the compounding ratio becomes larger, so that the viscosity of the composition tends to become lower. When a liquid epoxy resin composition is obtained, it is usually from 170 to
350, even 180-280, especially 190-2
00 is preferably used because it has excellent mechanical properties such as balance of viscosity, water absorption and curing reactivity and toughness of the cured product.

As the epoxy resin (A), for example, a bisphenol type epoxy resin or a biphenyl type epoxy resin obtained by silylation is preferable.

Preferred examples of the epoxy resin (A) include, for example, those represented by the following general formula (2):

[0032]

Embedded image

(Where X is CH ₂ , C (CH ₃ ) ₂ , CH
(CH ₃ ), -S-, direct bond (in case of biphenyl)
Wherein each X may be the same or different, R is the same as described above, and n is from 0.01 to
And the resin represented by 9). These may be used alone or in combination of two or more.
Among these, for example, the trade name Araldite AER
Bisphenol A type epoxy resin such as No. 260 (Asahi Chiba Co., Ltd.) can obtain a cured product having relatively low viscosity and relatively high glass transition temperature (Tg). Is preferred.

When a liquid epoxy resin composition is obtained, n in the general formula (2) is particularly preferably from 0.01 to 1, and more preferably from 0.1 to 0.6. The n
When is less than 0.01, the effect of substituting the hydroxyl group usually present in the epoxy resin with a silyl ether group becomes small, and it becomes difficult to reduce the hygroscopicity of the epoxy resin itself. In this case, the resin itself is solidified, the epoxy equivalent is increased, and the blending ratio of the phenol resin (B) is reduced, so that the tendency of the viscosity of the resin composition to increase tends to occur.

The method for producing the epoxy resin (A) is disclosed in
It is described in detail in Japanese Patent No. 245749, and is produced by blocking the hydroxyl group in a conventionally known epoxy resin by a known method using a substituted silylating agent having a substituted silyl group R.

Examples of conventionally known epoxy resins include, for example, bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, sulfide type epoxy resin, and glycidylamine type epoxy resin. Examples include epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, biphenyl-type epoxy resins, fluorene-type epoxy resins, and polyepoxy compounds such as dihydroxybenzene-type epoxy resins. These may be used alone or in combination of two or more. Among them, bisphenol A type epoxy resin is preferable from the viewpoint of balance of workability, heat resistance, economy and the like.

The substituted silylating agent having the substituted silyl group R is not particularly limited as long as it is in this range. Specific examples include substituted silyl halides, disilazane, N-silylamine, N-silylamine and the like. -Silylimidazoles, N-silylamides and the like.
These may be used alone or in combination of two or more. Of these, substituted silyl halides such as trimethylsilyl chloride are preferred because of their high reactivity and easy removal of by-products.

Here, as a preferred example of the silylated epoxy resin (A) used in the present invention, a method for producing a trimethylsilylated bisphenol A type epoxy resin will be described below.

For example, 1 mol of a bisphenol A type epoxy resin having an epoxy equivalent of 190 is well dissolved in 200 to 400 ml of dry toluene, and this solution is cooled to 0 to 5 ° C. in an ice bath under a nitrogen atmosphere. An equivalent amount of an acid acceptor such as triethylamine and a substituted silylating agent such as trimethylsilyl chloride (0.20 to 0.2
5 mol) and react at 0-5 ° C for about 2 hours. After completion of the reaction, by-products are removed by suction filtration, an equal mixture of cold water and toluene is added to the filtrate, and the mixture is shaken well with a separating funnel to remove an aqueous phase. The same washing operation is repeated two or three times. After washing with water, the organic phase is taken out, dried with a desiccant. After drying, toluene is removed by an evaporator, and the remaining product is dried under reduced pressure at about 80 ° C. to obtain a trimethylsilylated bisphenol A type epoxy resin.

The phenol resin (B) used in the epoxy resin composition of the present invention is a 2-allylphenol-formaldehyde polycondensate having an average degree of polymerization of less than 3.

The phenolic resin (B) has a viscosity of 1 at room temperature.
Since it is a liquid substance of 2,000 to 2,000 cP, it also has an advantage that a liquid epoxy resin composition can be obtained. By using the phenolic resin (B) as a curing agent for the silylated epoxy resin (A), various properties (low water absorption of the cured product, excellent electrical properties, Excellent hydrolysis resistance) can be achieved at the same time.

The curing reaction is carried out using a silylated epoxy resin (A)
And the phenolic hydroxyl group of the phenolic resin (B). That is, the epoxy group of the silylated epoxy resin (A) and the hydroxyl group contained in the phenol resin (B) are reacted with the reaction formula (a):

[0043]

Embedded image

(Where Y is a portion other than the glycidyl group of the epoxy resin (A) other than the glycidyl group to be reacted, and Z is a phenol resin (B)
The epoxy resin (A) and the phenolic resin (B) are copolymerized by the addition reaction represented by the following formula (b), and the hydroxyl group generated at that time is converted into a reaction formula (b):

[0045]

Embedded image

(Where Y and Z are the same as those described above), or by anionic polymerization of a further epoxy group, a three-dimensional network structure is formed and curing is achieved. However, 3 in one molecule in the phenolic resin (B)
A molecule containing two or more hydroxyl groups can naturally have a crosslinked structure without performing the reaction represented by the reaction formula (b).

The cured product thus obtained satisfies the above-mentioned various properties at the same time.

The phenolic resin (B) is a polycondensate of 2-allylphenol and formaldehyde, and has an average degree of polymerization of less than 3. In particular, the average degree of polymerization is 1.8-2.
5 or 1.9 to 2.1, the point that a sufficient cross-linking structure is formed, a relatively low-viscosity resin composition can be obtained, and the curing reaction proceeds smoothly. It is preferable because a low cured product can be obtained. If the average degree of polymerization is less than 1.8, there is a tendency that a sufficient crosslinked structure cannot be obtained even when the composition is cured, and various properties such as heat resistance and mechanical properties tend to decrease. When the average degree of polymerization is 3 or more, the viscosity of the phenolic resin increases, so that undesired tendencies such as an increase in the viscosity of the obtained epoxy resin composition, a slow curing reaction, and an increase in water absorption tend to occur.

Since the silylated epoxy resin (A) requires a step of silylation, it is generally expensive, and may be used in combination with a non-silylated epoxy resin for cost reduction.

The amount of the non-silylated epoxy resin used is determined by the total amount of the epoxy resin in order to sufficiently exhibit the characteristics of the present invention such as low water absorption of the cured product, excellent electrical properties, and high hydrolysis resistance. The content of the non-silylated epoxy resin in the resin is 50% or less, and more preferably 20% or less.
It is preferable to make the following.

Examples of the non-silylated epoxy resin include bisphenol A-type epoxy resin, naphthalene-type epoxy resin, biphenyl-type epoxy resin and the like, which have a low hygroscopicity and can reduce the crosslink density.
It is preferable to use a diluent which is a functional epoxy compound from the viewpoint of low moisture absorption of the composition, and to use an alicyclic epoxy resin or a diluent which is a bifunctional or higher epoxy compound to reduce the viscosity or increase the viscosity. It is preferable from the viewpoint of heat resistance.

The phenol resin (B) is also a conventionally known phenol resin, for example, a phenol novolak resin, a cresol novolak resin, in order to reduce the cost and increase the heat resistance.
Diallyldihydroxynaphthalene, diallylbisphenol A, diallylbisphenol AD, pyrogallol,
It may be used in combination with other phenolic resins such as phloroglucin.

The amount of the other phenol resin used is as follows:
In order to fully exhibit the features of the present invention such as low water absorption, excellent electric properties, and high hydrolysis resistance, the content of other phenolic resins in all phenolic resins should be 30% or less, further 10% or less. In order to obtain the effect of using the other phenolic resin, it is preferable to use the phenolic resin in an amount of 1% or more, more preferably 5% or more.

As the other phenolic resin, it is preferable to use a diallyl compound such as diallyldihydroxynaphthalene or diallylbisphenol A from the viewpoint of reducing the viscosity of the epoxy resin composition.

The total amount of the phenolic resin (B) and the other phenolic resin is not particularly limited as long as it can exhibit the properties inherent in the cured product. Usually, the phenolic hydroxyl group in the total of the phenolic resin (B) and the other phenolic resin is 0 per equivalent of the epoxy group in the total of the silylated epoxy resin (A) and the non-silylated epoxy resin. 0.3 to 1.2 equivalents, more preferably 0.5 to 1.0 equivalent. When the amount of the phenolic hydroxyl group used per equivalent of the epoxy group exceeds 1.2 equivalents, no effect beyond the original properties of the cured product can be obtained, which is rather a curing failure or a feature of the present invention. The properties tend to decrease, and when the amount of the phenolic hydroxyl group used is less than 0.3 equivalent, the properties which are the characteristics of the present invention tend to be hardly obtained.

A preferred embodiment of the present invention is, for example, a compound represented by the following general formula (3):

[0057]

Embedded image

100 parts (parts by weight, hereinafter the same) of the silylated epoxy resin (A) represented by (n is 0.01 to 9)
In contrast, the general formula (4):

[0059]

Embedded image

The phenol resin (B) represented by
To 100 parts, preferably 3 to 85 parts (a phenolic hydroxyl group equivalent of 0.3 to 1.2, preferably 0.5 to 1.0 per equivalent of epoxy group). .

Various conventionally known curing accelerators can be used in the epoxy resin composition of the present invention. Examples of the curing accelerator include urea-based curing accelerators, quaternary ammonium salts, amine adduct-based curing accelerators, tertiary amines, imidazoles, aliphatic carboxylate salts, organic phosphorus compounds, and the like. It is not limited to these. The amount of the curing accelerator used is appropriately selected depending on the type of the curing accelerator, and is usually 100 parts by weight of the epoxy resin (the total amount of the epoxy resin (A) and the non-silylated epoxy resin). , 1 to 8 parts, more preferably 1 to 5 parts. Further, by using a latent curing accelerator, a one-pack type resin composition having a long pot life can be obtained.

The epoxy resin composition of the present invention may contain various conventionally known inorganic fillers. The type and amount of the inorganic filler are appropriately selected according to the application and the viscosity of the resin composition. Conventionally known inorganic fillers include, for example, fused silica powder, quartz glass powder, crystalline silica powder, glass fiber, talc, alumina powder, calcium silicate powder, calcium carbonate powder, antimony oxide powder, barium sulfate powder, titanium oxide Powder, aluminum hydroxide powder and the like. When the application of the obtained resin composition is in the field of electronics and semiconductors, a high-purity product is obtained, and fused silica powder or quartz glass powder having a small linear expansion coefficient is more suitable.

The epoxy resin composition of the present invention may further contain various coupling agents, defoaming agents, and low-stressing agents within a range that does not adversely affect the water absorption, electric properties, hydrolysis resistance, and the like of the cured product. Various additives such as rubber particles, pigments and the like may be blended.

The epoxy resin composition of the present invention comprises a silylated epoxy resin (A), a phenolic resin (B), the non-silylated epoxy resin and other phenolic resins used as required, and a curing accelerator. , Inorganic fillers and other various additives are uniformly mixed with a stirrer. Stirring and mixing are usually performed at room temperature.For example, when the temperature is high or when the amount of the inorganic filler added is large, cooling is performed to suppress heat generation, or the viscosity at the time of stirring is high and stirring efficiency is high. When bad, heating may be performed. In particular, in the case of producing a one-pack type resin composition, it is preferable to cool in order to prevent the progress of the reaction due to heat generation.

The cured product of the present invention can be obtained by thermally curing the epoxy resin composition of the present invention.

The heating condition is not particularly limited as long as it is a condition under which the original performance of the cured product can be exhibited.
Usually, in order to suppress curing shrinkage and reduce residual stress, step curing is performed in which the temperature is gradually increased in several stages, and at this time, the resin composition is gelled in the curing stage at a low temperature. Adjust the heating conditions. According to this curing method, the residual stress of the cured product after cooling becomes small, and the heating condition is mild, so that the resin composition hardly deteriorates due to heat generation due to rapid progress of the curing reaction.

The preferred heating conditions are not particularly limited. For example, in step curing consisting of two to three steps, the heating temperature is 100 to 150 ° C. in the first step, 140 to 190 ° C. in the second step, and 180 to 180 ° in the third step. 230 ℃,
The heating time is about 1 to 3 hours for each stage.

The cured product of the present invention thus obtained has a glass transition temperature of 50 to 80 ° C., and more preferably 70 to 1
An epoxy resin cured product having a temperature of about 00 ° C., low hygroscopicity and excellent electrical properties.

[0069]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. The raw materials and abbreviations used in the examples are shown below.

Silylated epoxy resin (A): trimethylsilylated bisphenol A type epoxy resin (epoxy equivalent: 195, number average molecular weight: 390; manufactured in Production Example 1 described later) Epoxy resin (a): dihydroxynaphthalenediglycidyl ether ( Epoxy equivalent 141, manufactured by Dainippon Ink and Chemicals, Inc.) Epoxy resin (b): bisphenol A type epoxy resin (epoxy equivalent 190, manufactured by Asahi Ciba Co., Ltd.) Phenol resin (B): 2-allylphenol-
Formaldehyde condensate (trade name: BPF-ST-C
A) (Average degree of polymerization 2, hydroxyl equivalent 150, manufactured by Mitsui Toatsu Chemicals, Inc.) Phenol resin (A): bis (3-allyl-4-)
Hydroxyphenyl) propane (trade name: BPA-C)
A) (Average degree of polymerization 2, hydroxyl equivalent 160, manufactured by Mitsui Toatsu Chemicals, Inc.) Phenol resin (b): Allylated phenol novolak resin (trade name: AL-VR-9300) (Average degree of polymerization 3, hydroxyl equivalent) 150, manufactured by Mitsui Toatsu Chemical Co., Ltd.) Acid anhydride (c): methyl hexahydrophthalic anhydride Anhydride (d): methyl tetrahydrophthalic anhydride 2MZ: 2-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd.) In addition, evaluations in Examples and Comparative Examples are collectively shown below.

(1) Glass transition temperature 1.5 g of the obtained resin composition was 4 cm in diameter and 10 m in thickness.
m in a circular coin mold, 100 ° C for 1 hour,
Further, the cured product obtained by curing at 150 ° C. for 1 hour and further at 180 ° C. for 1 hour was subjected to a PCT test at 120 ° C. for 2 hours.
Exposure was carried out for a predetermined time under atmospheric pressure to absorb water, and the glass transition temperature after water absorption was measured using a differential scanning calorimeter (DSC210,
(Seiko Electronics Co., Ltd.). The heating was performed at a heating rate of 16 ° C./min, and the inflection point of the specific heat capacity was defined as the glass transition temperature. By this measurement, the degree of deterioration of the cured product due to hydrolysis can be known from the degree of decrease in the glass transition temperature.

(2) Water Absorption Rate A circular coin-shaped cured product was prepared in the same manner as described above, and water was absorbed for a predetermined time in a PCT test under the same conditions, and the water absorption was calculated by the formula: water absorption rate (%) = (after water absorption) Weight-initial weight) ÷ initial weight × 100.

(3) Average Degree of Polymerization of Phenolic Resin A sample was analyzed by gel permeation chromatography (GPC).

A sample was prepared as a tetrahydrofuran solution, and measured using a high performance liquid chromatography model 600F (manufactured by Nippon Millipore Limited), the number average molecular weight was calculated in terms of polystyrene, and the average degree of polymerization was calculated.

Production Example 1 380 g (1.0 mol) of a bisphenol A type epoxy resin (epoxy equivalent 190) and 300 ml of dry toluene were placed in a 1-liter three-necked flask.
Dissolved well. The solution was cooled to 0-5 ° C. in an ice bath under a nitrogen atmosphere. To this, 21.25 g (0.21 mol) of triethylamine and 22.81 g (0.21 mol) of trimethylsilyl chloride were added.
The reaction was performed at 5 ° C. for 2 hours. After completion of the reaction, the by-product triethylamine hydrochloride was removed by suction filtration, and 20 mL of the filtrate was added.
0 ml of cold water and 200 ml of toluene were added, and the mixture was shaken well with a separating funnel to remove an aqueous phase. The same water washing operation was repeated three times, and after washing with water, the organic phase was taken out and dried over anhydrous magnesium sulfate. After drying, toluene was removed by an evaporator, and the remaining product was dried under reduced pressure at 80 ° C. to obtain a compound of the formula (5):

[0076]

Embedded image

A trimethylsilylated bisphenol A type epoxy resin represented by the following formula (epoxy equivalent: 195) was obtained.

Example 1 100 parts of a silylated epoxy resin (A), 38 parts of a phenol resin (B) and 2 parts of 2MZ were mixed to obtain an epoxy resin composition. The obtained epoxy resin composition was liquid and had a viscosity of 7,000 cP at 25 ° C. The obtained epoxy resin composition was evaluated according to the above evaluation method. Table 1 shows the results.

Comparative Examples 1 to 14 In the same manner as in Example 1, the components were mixed at the ratios shown in Tables 1 to 3 to obtain epoxy resin compositions. All compositions were liquid. The obtained epoxy resin composition was evaluated according to the above evaluation method. The results are shown in Tables 1, 2 and 3.

[0080]

[Table 1]

[0081]

[Table 2]

[0082]

[Table 3]

[0083]

According to the present invention, the combination of a silylated epoxy resin, which itself exhibits low hygroscopicity and excellent electrical properties, and a specific phenol resin, is cured. The hygroscopicity is further significantly reduced.

Claims (2)

[Claims] (A) a compound formed by ring-opening of an epoxy group
The hydroxyl group in the CH ₂ —CH (OH) — structure is an aliphatic group,
An epoxy resin in which an aromatic group and / or a heterocyclic group are blocked by a hydrophobic non-reactive silyl group bonded to a silicon atom and containing two or more epoxy groups, and (B) 2-allyl An epoxy resin composition containing a phenol-formaldehyde polycondensate (average degree of polymerization less than 3). 2. A cured product obtained by thermally curing the epoxy resin composition according to claim 1.