TW201518392A - Epoxy resin composition, use thereof and filler for epoxy resin composition - Google Patents

Abstract

The present invention provides a thermally conductive epoxy resin composition containing magnesium oxide powder which may be easily prepared by means of kneading and mixture, having excellent moldability, improved flowability and good water absorption (low water absorption). Also provided is a thermally conductive epoxy resin composition containing magnesium oxide powder which preferably has excellent flame retardancy. The epoxy resin composition of the present invention may be properly useful as thermally conductive sealing material, thermally conductive sheet, thermally conductive adhesive and cured product. The epoxy resin composition of the present invention is characterized by comprising epoxy resin, curing agent, and magnesium oxide powder surface-treated with an alkoxysilane having at least one of phenyl group and amino group.

Description

Epoxy resin composition, use thereof and filler for epoxy resin composition

The present invention relates to a thermally conductive epoxy resin composition containing magnesium oxide powder, and a thermally conductive sealing material, a thermal conductive sheet, a thermally conductive adhesive, a cured product, and an oxidation-containing material comprising the thermally conductive epoxy resin composition. A filler for an epoxy resin composition of magnesium powder. In particular, it is a thermally conductive epoxy resin composition which can be easily prepared by kneading and has improved fluidity, is excellent in moldability, has good water absorbability (low water absorption), and is preferably excellent in combustion resistance.

Epoxy resin compositions are used in a variety of applications for a variety of applications.

Particularly, in electronic parts, it is suitably used as a substrate material, a sealing material, a thermal conductive sheet material, an adhesive, and the like. In this application, there has been a tendency to increase the amount of heat generation from electronic components due to the development of miniaturization, high integration, high capacitance, and high speed. If the amount of heat is increased, the reliability of the electronic parts may be lowered due to the influence of temperature or humidity. Therefore, in addition to heat resistance and low water absorption (moisture resistance), the epoxy resin composition is required to impart heat conductivity in order to improve heat dissipation.

Further, although the flame retardancy is not necessarily required in the case of the adhesive or the coating material, in the case of directly sealing the heat release source such as a semiconductor sealing material, high flame resistance as an electronic component is required in consideration of safety.

In order to impart thermal conductivity to the epoxy resin composition, blending oxidation has been proposed. magnesium. Magnesium oxide is used to improve thermal conductivity. However, when the blending amount is increased, the fluidity is lowered and the moldability is insufficient. Therefore, in particular, the electronic component which is miniaturized (thinned, miniaturized, and complicated) has a problem in formability.

Patent Document 1 proposes a resin composition containing magnesium oxide powder which is excellent in moisture resistance and thermal conductivity. In the case where the magnesium oxide is surface-treated with an inorganic coupling agent such as decane, the surface treatment agent is easily peeled off from the surface of the magnesium oxide in the kneading operation step with the resin, and the mechanical strength is lacking. The surface is subjected to a hydration reaction to be converted into magnesium hydroxide, which causes whitening, and thus cannot be practically applied. Here, coated magnesium oxide is used, and the surface thereof has a coating layer containing a composite oxide of cerium and magnesium and/or a composite oxide of aluminum and magnesium.

Patent Document 2 proposes an epoxy resin composition having improved thermal conductivity (heat dissipation) by blending a magnesium oxide powder and a ceria powder with a specific volume ratio. It is described that the surface of the magnesium oxide is treated with a decane coupling agent, and in the examples, magnesium oxide treated with an oligomeric reactive siloxane is used. However, the usual (compound type) decane coupling agent is not necessarily studied in detail.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-27177

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2012-162650

An object of the present invention is to provide a thermally conductive epoxy resin composition containing magnesium oxide powder which can be easily prepared by kneading and which has improved fluidity and is excellent in moldability and water absorption (low water absorption). Further, an object of the present invention is to provide a thermally conductive epoxy resin composition containing magnesium oxide powder which is preferably excellent in further resistance to combustion. The epoxy resin composition of the present invention can be suitably used as a thermally conductive sealing material, a thermal conductive sheet, a thermally conductive adhesive, and a cured product.

The present invention relates to the following matters.

An epoxy resin composition comprising an epoxy resin, a hardener, and a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amine group.

2. The epoxy resin composition according to item 1, wherein the alkoxydecane is a compound represented by the following chemical formula (1).

(R') _l Si(OR) _4-l (1)

In the chemical formula (1), l is an integer of 1 to 3, R is an alkyl group which may be the same or different, and R' is a monovalent group containing at least one of a phenyl group and an amine group which may be the same or different.

3. The epoxy resin composition according to item 1 or 2, wherein the hardener is a phenol resin.

4. The epoxy resin composition according to Item 3, wherein the phenol resin is at least one selected from the group consisting of a phenylaralkyl type phenol resin and a biphenyl aralkyl type phenol resin.

A thermally conductive sealing material comprising the epoxy resin composition according to any one of items 1 to 4.

A thermally conductive sheet comprising the epoxy resin composition according to any one of items 1 to 4.

A thermally conductive adhesive comprising the epoxy resin composition according to any one of items 1 to 4.

A cured product obtained by hardening the epoxy resin composition according to any one of items 1 to 4.

An epoxy resin composition comprising an epoxy resin and a hardener composed of one or more phenol resins selected from the group consisting of a phenylaralkyl type phenol resin and a biphenyl aralkyl type phenol resin. And magnesium oxide powder.

A filler for an epoxy resin composition comprising a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amine group.

According to the present invention, it is possible to provide a thermally conductive epoxy resin composition containing magnesium oxide powder which can be easily prepared by kneading and which has improved fluidity and is excellent in moldability and water absorbability (low water absorption). Further, according to the present invention, it is possible to provide a thermally conductive epoxy resin composition containing magnesium oxide powder which is preferably excellent in further resistance to combustion. The epoxy resin composition of the present invention can be suitably used as a thermally conductive sealing material, a thermal conductive sheet, a thermally conductive adhesive, and a cured product.

The present invention relates to an epoxy resin composition comprising an epoxy resin, a hardener, and a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amine group.

The epoxy resin of the epoxy resin composition of the present invention is not particularly limited as long as it is an epoxy resin having two or more epoxy groups in the molecule, and examples thereof include a bisphenol type and a phenol novolak type. , cresol novolak type, biphenyl type, triphenylmethane type, two An epoxy resin such as a cyclopentadiene type or a naphthol type. These epoxy resins may be used singly or in combination of two or more. Among these epoxy resins, a cresol novolac type epoxy resin and a biphenyl type epoxy resin are particularly preferable.

The curing agent of the epoxy resin composition of the present invention is not particularly limited as long as it is a curing agent which can react with an epoxy resin to obtain a cured product, and an amine compound which is generally used as a curing agent for an epoxy resin can be suitably used. , acid anhydride, phenol resin, and the like.

The hardener of the epoxy resin composition of the present invention is preferably a phenol resin. The phenol resin is not particularly limited, and examples thereof include a phenol novolak type, a cresol novolak type, a phenyl aralkyl type, a biphenyl aralkyl type, a triphenylmethane type, and a dicyclopentane. Among these, a novolac type phenol resin such as an ene type or a naphthol type can be particularly preferably used in the form of a phenylaralkyl type in terms of low water absorbability and further improvement in flame resistance (flame retardancy). Phenolic resin and biphenyl aralkyl type phenol resin.

The phenylaralkyl type phenol resin and the biphenyl aralkyl type phenol resin have a representative group containing -CH ₂ -Bz-CH ₂ - or -CH ₂ -Bz-Bz-CH ₂ -( A phenolic varnish-type phenolic resin having a chemical structure of a phenylene skeleton such as a benzene ring or a divalent crosslinking group of a biphenylene skeleton (phenylaralkyl or biphenyl aralkyl) bonded to a phenol Further, it is preferably a chemical structure having the following chemical formulas (2) to (5), and more preferably having the chemical structure of the following chemical formulas (4) to (5).

In the chemical formula (2), n is an integer of 1 or more (preferably an integer of 1 to 20), R ₁ is an alkyl group having 1 to 6 carbon atoms or a hydroxyl group, and p is an integer of 0 to 2.

In the chemical formula (3), m is an integer of 1 or more (preferably an integer of 1 to 20), n is an integer of 1 or more (preferably an integer of 1 to 20), and R ₁ is an alkyl group having 1 to 6 carbon atoms. Or any of the hydroxyl groups, p is an integer of 0-2.

In the chemical formula (4), n is an integer of 1 or more (preferably an integer of 1 to 20), R ₁ is an alkyl group having 1 to 6 carbon atoms or a hydroxyl group, and p is an integer of 0 to 2.

In the chemical formula (5), m is an integer of 1 or more (preferably an integer of 1 to 20), n is an integer of 1 or more (preferably an integer of 1 to 20), and R ₁ is an alkyl group having 1 to 6 carbon atoms or Any of the hydroxyl groups, p is an integer of 0-2.

In the epoxy resin composition of the present invention, the blending ratio of the epoxy resin and the curing agent is not particularly limited, and when the blending amount of the epoxy resin is 100 parts by mass, the curing agent is preferably 50 to 120 parts by mass. The scope.

The magnesium oxide powder used in the epoxy resin composition of the present invention is a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amine group.

The magnesium oxide powder is not particularly limited, and can be suitably obtained, for example, by heat-treating magnesium hydroxide to about 1400 ° C or higher to about 2800 ° C (melting temperature). In the present invention, the magnesium oxide powder obtained by firing at a temperature of preferably 1600 ° C or higher to less than 2600 ° C, more preferably 2000 to 2400 ° C, can be suitably used. Further, the magnesium oxide powder of the present invention is not particularly limited, and the average particle diameter is preferably in the range of 0.5 to 100 μm, more preferably in the range of 1 to 80 μm, and the purity is preferably in the range of 94.0% by mass or more, and more preferably 96.0%. A range of 99.7 mass%.

The surface-treated alkoxydecane used for the magnesium oxide used in the present invention is an alkoxydecane having a chemical structure containing at least one of a phenyl group and an amine group in the molecule (as a compound, not an oligomer) It is preferably an alkoxydecane represented by the following chemical formula (1). Particularly, from the viewpoint of fluidity, the alkoxydecane preferably contains a phenyl group.

(R') _l Si(OR) _4-l (1)

In the formula (1), l is an integer of 1 to 3, and R is an alkyl group which may be the same or different, respectively (preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group), and R' is The monovalent group containing at least one of a phenyl group and an amine group may be the same or different, respectively.

Specific examples of such alkoxydecanes include the respective compounds represented by the following chemical formula (6).

Further, the amount of the alkoxydecane to be treated is not particularly limited, and is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, based on the magnesium oxide powder.

In the present invention, fluidity (swirl) which can be easily prepared by kneading and formed can be obtained by using magnesium oxide whose surface is treated with an alkoxysilane having at least one of a phenyl group and an amine group. A thermally conductive epoxy resin composition which is excellent in formability and further low in water absorbability.

The surface treatment method of the magnesium oxide powder is not particularly limited, and the surface treatment can be carried out by, for example, a dry reaction method or a wet reaction method. The dry reaction method is a method in which a magnesium oxide powder is added to a device capable of high-speed stirring such as a Henschel mixer, and a hydrolyzate of alkoxysilane or alkoxysilane is added while stirring. As a method of adding the mixture, a method in which the alkoxydecane can be uniformly reacted is preferably used, and a known method such as slow dropwise addition can be used. The method, the method of spraying into a mist, the method of introducing gaseous decane, etc. The wet reaction method is a method in which a reaction is carried out in a state where a magnesium oxide powder is dispersed in a solution of alkoxysilane, and if necessary, dried. As the solvent to be used, water, an alcohol or a mixture of these is preferred.

The magnesium oxide powder may be used singly or in combination with other inorganic fillers. The blending ratio of the inorganic filler containing the magnesium oxide powder is in the range of 10 to 95% by volume, preferably 30 to 90%, more preferably 60 to 75%, based on the total of the epoxy resin composition. The scope. Examples of the inorganic filler other than the magnesium oxide powder to be used include cerium oxide, aluminum oxide, aluminum nitride, cerium nitride, calcium carbonate, talc, mica, barium sulfate, etc., among which dioxide is preferably used.矽 powder. The blending ratio of the magnesium oxide powder and the other inorganic filler used in combination is preferably in the range of 100:0 to 5:95, more preferably 60:40, in terms of volume ratio [magnesia powder: other inorganic fillers used in combination]. The range of 5:95, and more preferably the range of 40:60 to 25:75.

In the epoxy resin composition of the present invention, in addition to the epoxy resin, the curing agent, and the inorganic filler containing the magnesium oxide powder, various components used in the usual epoxy resin composition may be blended depending on the application.

For example, a curing accelerator can also be suitably used. As the curing accelerator, a curing accelerator used in a general epoxy resin composition can be used. When a phenol resin is used as the curing agent, a compound which activates a hydroxyl group of the phenol resin is preferable. Examples of the curing accelerator include amine compounds such as benzyldimethylamine, triethanolamine, and dimethylaminoethanol, and tributylphosphine, methyldiphenylphosphine, and triphenylphosphine. An organic phosphorus compound such as diphenylphosphine. The blending amount of the hardening accelerator is preferably from 0.1 to 10 parts by mass, more preferably from 1 to 7 parts by mass, per 100 parts by mass of the blending amount of the epoxy resin.

Further, in the epoxy resin composition of the present invention, various other additives may be used depending on the use. For example, in the use of a thermally conductive sealing material, a releasing agent, a coloring agent, a flame retardant, a low stress agent, or the like can be used, and in the use of a thermal conductive sheet, an adhesion-imparting agent, an anti-aging agent, or a softening agent can be used (for example) Naphthenic oil, alkane oil, etc.), thixotropic agent (such as montmorillonite), lubricant (such as stearic acid, etc.), pigment, anti-coking agent, stabilizer, antioxidant, ultraviolet absorber, coloring For the use of the thermal conductive adhesive, a pigment, an ultraviolet absorber, or the like can be used as the agent, the antifungal agent, the foaming agent, and the like.

That is, the epoxy resin composition of the present invention can be suitably used as a thermally conductive sealing material, a thermal conductive sheet, or a thermally conductive adhesive.

Further, the epoxy resin composition of the present invention can be subjected to a heat treatment to cause a hardening reaction to form a cured product. The conditions for curing the epoxy resin composition of the present invention can be appropriately selected. For example, a cured product can be obtained by heat treatment at 50 to 300 ° C, preferably 130 to 250 ° C for 0.01 to 20 hours, preferably 0.1 to 10 hours.

[Examples]

Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited to these Examples.

The kneading step in the preparation of the epoxy resin composition was evaluated by the following method.

(1) Skilledness

A specific amount of epoxy resin, a phenol resin as a curing agent, a magnesium oxide powder as a filler, and cerium oxide powder are kneaded at a specific temperature by a biaxial kneader, and the discharge port from the twin-axis kneader is visually observed. The discharged kneaded material was evaluated. As a benchmark for evaluation, it is set to ○: Can be mixed without any problem, △: can be mixed but the mixture is not uniform, ×: can not be mixed.

Further, the epoxy resin composition was evaluated by the following method. Further, the epoxy resin composition powder was molded into an ingot, and the ingot was evaluated as a sample. The ingot was formed by pressing with a hand pressure of 450 MPa for 1 minute.

(2) Formability

The sample was molded into a molded body by a transfer molding machine under the following conditions: a mold temperature of 175 ° C, an injection pressure of 6.9 MPa, a pressurization for 30 seconds, and a pressurization of 3.0 MPa for 70 seconds. As a criterion for evaluation of moldability, it is assumed that ○: can be formed without any problem, and ×: cannot be formed.

(3) Fluidity (swirl)

The swirling value of the sample was measured by a transfer molding machine and a mold for swirling measurement (according to EMMI-1-66). Further, the fluidity was evaluated under the following conditions: the mold temperature was set to 175 ° C, the injection pressure was set to 6.9 MPa, and the pressure was maintained for 60 seconds and held for 40 seconds.

Further, the cured product of the epoxy resin composition was evaluated by the following method.

(4) Water absorption (water absorption)

The sample was formed into a disk shape having a thickness of 3 mm × a diameter of 50 mm by a transfer molding machine, and then hardened at 180 ° C for 8 hours to obtain a test piece (cured product). The obtained test piece was measured for mass (W ₁ ), and maintained in pure water heated to a temperature of 95 ° C for 24 hours, and then taken out from pure water and wiped off water, and then the mass (W ₂ ) was measured. The amount of water absorption was calculated by the following formula.

Water absorption (g/cm ³ )={W ₂ (g)-W ₁ (g)}/volume of test piece (cm ³ )

(5) Flame retardancy (flame resistance)

The sample was molded into a shape having a thickness of 1 mm, a width of 13 mm, and a length of 127 mm by a transfer molding machine, and then hardened at 180 ° C for 8 hours to obtain a test piece (cured product). The test obtained The sheets were evaluated for flame retardancy in accordance with the UL-94 test method.

(6) Thermal conductivity

The sample was molded into a shape having a thickness of 4 mm, a width of 50 mm, and a length of 100 mm by a transfer molding machine, followed by hardening at 180 ° C for 8 hours to obtain a cured product. The obtained cured product was cut into a shape having a thickness of 4 mm, a width of 25 mm, and a length of 25 mm, and was set as a test piece. The thermal conductivity of the test piece was measured using a thermal conductivity measuring device GH-1 manufactured by ULVAC Co., Ltd.

The materials used in the following examples are as follows.

(a) Epoxy resin

Biphenyl type epoxy resin, YX-4000, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186g/eq, viscosity: 0.2P/150°C, melting point: 105°C (DSC method)

(b) hardener

(b1) hardener 1

The phenol formaldehyde type phenol resin represented by the following chemical formula (7) has a hydroxyl equivalent: 107 g/eq, a viscosity: 2.0 P/150 ° C, and a softening point: 84 ° C.

In the chemical formula (7), n is an integer of 1 or more.

(b2) hardener 2

a biphenyl aralkyl type phenol resin represented by the following chemical formula (8), having a hydroxyl equivalent: 201 g/eq, Viscosity: 0.8P/150°C, softening point: 67°C

In the chemical formula (8), n is an integer of 1 or more.

(b3) hardener 3

The biphenyl aralkyl type phenol resin represented by the following chemical formula (9), hydroxyl equivalent: 166 g/eq, viscosity: 0.5 P/150 ° C, softening point: 62 ° C

In the chemical formula (9), m is an integer of 1 or more, and n is an integer of 1 or more.

(c) hardening accelerator

Triphenylphosphine, manufactured by Beixing Chemical Co., Ltd.

(d) Magnesium oxide powder

The magnesium oxide powder is produced by firing and grading magnesium hydroxide at 2000 ° C by a rotary kiln. The surface treatment by the alkoxy decane was carried out by heating and stirring at 120 ° C for 10 minutes by using a high-speed flow stirrer to add 0.5% by mass of alkoxysilane with respect to magnesium oxide.

(d1) Magnesium Oxide Powder 1

Magnesium oxide powder treated with phenyltrimethoxydecane, average particle size: 5.5 μm

(d2) Magnesium Oxide Powder 2

Magnesium oxide powder treated with N-2-aminoethyl-3-aminopropyltrimethoxydecane, average particle size: 6.1 μm

(d3) Magnesium Oxide Powder 3

Magnesium oxide powder treated with 3-glycidoxypropyltrimethoxydecane on the surface, average particle size: 6.8 μm

(d4) Magnesium Oxide Powder 4

Magnesium oxide treated with vinyltrimethoxydecane on the surface, average particle size: 6.2 μm

(d5) Magnesium oxide powder 5

Magnesium oxide powder without surface treatment, average particle size: 6.5 μm

(e) cerium oxide powder

MSR-2212, manufactured by Longsen Co., Ltd., average particle size: 25μm

[Example 1]

As shown in Table 1, 100 g (100 parts by mass) of YX-4000 as an epoxy resin and a curing agent 1 (phenol formaldehyde type phenol resin) as a curing agent were used under the temperature conditions shown in Table 1 by a biaxial kneader. 57 g (57 parts by mass), 2.7 g (2.7 parts by mass) of triphenylphosphine as a curing accelerator, 532 g (532 parts by mass) of cerium oxide powder (MSR-2212) as a filler, and surface phenyl trimethoxide 1 424 g (424 parts by mass) of the oxydecane-treated magnesium oxide powder was kneaded to obtain a kneaded product of the epoxy resin composition. Observe the mixing steps at this time.

After the obtained kneaded material was cooled to room temperature, it was pulverized by a pulverizer and pulverized. The powder is press-formed by a specific mold to form an ingot composed of an epoxy resin composition. Will The ingot was used as a sample to evaluate fluidity (swirl). Further, the sample was molded into a specific size by a transfer molding machine, and cured at 180 ° C for 8 hours to prepare a test piece (cured product) of a specific size.

[Embodiment 2]

As shown in Table 1, an epoxy resin composition was obtained in the same manner as in Example 1 except that the hardener 2 (biphenyl aralkyl type phenol resin) was used instead of the hardener 1 (phenol formaldehyde type phenol resin) as a hardener. The mixture of things. In addition, the evaluation was carried out.

[Example 3]

As shown in Table 1, magnesium oxide powder 2 having a surface treated with N-2-aminoethyl-3-aminopropyltrimethoxydecane was used instead of magnesium oxide powder 1, and was obtained in the same manner as in Example 2. A kneaded mixture of epoxy resin compositions. In addition, the evaluation was carried out.

[Example 4]

As shown in Table 1, an epoxy resin composition was obtained in the same manner as in Example 1 except that the hardener 3 (biphenyl aralkyl type phenol resin) was used instead of the hardener 1 (phenol formaldehyde type phenol resin) as a hardener. The mixture of things. In addition, the evaluation was carried out.

[Comparative Example 1]

As shown in Table 1, a kneaded product of the epoxy resin composition was obtained in the same manner as in Example 1 using only cerium oxide powder. In addition, the evaluation was carried out.

[Comparative Example 2]

As shown in Table 1, the magnesium oxide powder 3 treated with 3-glycidoxypropyltrimethoxydecane was used instead of the magnesium oxide powder 1, and the epoxy resin composition was kneaded in the same manner as in Example 1. Things. In addition, the evaluation was carried out.

[Comparative Example 3]

As shown in Table 1, a kneaded material of the epoxy resin composition was obtained in the same manner as in Example 1 except that the magnesium oxide powder 4 having a surface treated with vinyltrimethoxydecane was used instead of the magnesium oxide powder 1. In addition, the evaluation was carried out.

[Comparative Example 4]

As shown in Table 1, a magnesia powder 5 which was not treated with a surface was used instead of the magnesium oxide powder 1, and a kneaded product of the epoxy resin composition was obtained in the same manner as in Example 1, but was not obtained.

[Reference Example 1]

As shown in Table 1, a kneaded material of the epoxy resin composition was obtained in the same manner as in Example 2, except that the magnesium oxide powder 4 having a surface treated with vinyltrimethoxydecane was used instead of the magnesium oxide powder 1. In addition, the evaluation was carried out.

[Reference Example 2]

As shown in Table 1, a kneaded material of the epoxy resin composition was obtained in the same manner as in Example 2, except that the magnesium oxide powder 5 which was not treated with the surface was used instead of the magnesium oxide powder 1. In addition, the evaluation was carried out.

Table 1 shows the compositions, evaluation results, and the like of the examples and comparative examples.

As shown in Table 2, it is understood that Example 1 using the magnesium oxide powder 1 can obtain an epoxy resin having improved kneadability, and particularly improved fluidity and excellent moldability, as compared with Comparative Examples 2 to 4 in which magnesium oxide powders 3 to 5 are used. Resin composition.

As shown in Table 3, it can be seen that Examples 2 and 3 using magnesium oxide powders 1 and 2 can be used. An epoxy resin composition having improved kneadability and improved fluidity and excellent moldability as compared with Reference Examples 1 and 2 of the magnesium oxide powders 4 and 5 was obtained. According to Example 4, this effect is also effective for the hardener 3.

As shown in Table 4, it is understood that the thermal conductivity is improved in Examples 1 to 4 as compared with Comparative Example 1 in which magnesium oxide is not used. Regarding the flame retardancy, according to Example 1 and Comparative Example 1 using the curing agent 1, it was found that the flame retardancy was lowered by using the magnesium oxide powder. However, it can be seen that by using the curing agents 2 and 3, the flame retardancy is improved, so that V-0 can be achieved.

[Industrial availability]

According to the present invention, it is possible to provide a preparation which can be easily prepared by kneading, in particular It is a thermally conductive epoxy resin composition containing magnesium oxide powder which is excellent in fluidity, and is excellent in moldability and water absorption (low water absorption). Further, according to the present invention, it is possible to provide a thermally conductive epoxy resin composition containing magnesium oxide powder which is preferably excellent in further resistance to combustion. The epoxy resin composition of the present invention can be suitably used as a thermally conductive sealing material, a thermal conductive sheet, a thermally conductive adhesive, and a cured product.

Claims (10)

An epoxy resin composition comprising an epoxy resin, a hardener, and a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amine group. The epoxy resin composition according to the first aspect of the invention, wherein the alkoxydecane is a compound represented by the following chemical formula (1), (R') _l Si(OR) _4-l (1) (chemical formula In (1), l is an integer of 1 to 3, R is an alkyl group which may be the same or different, and R' is a monovalent group containing at least one of a phenyl group and an amine group which may be the same or different, respectively. The epoxy resin composition according to claim 1 or 2, wherein the curing agent is a phenol resin. The epoxy resin composition according to claim 3, wherein the phenol resin is one or more phenol resins selected from the group consisting of a phenylaralkyl type phenol resin and a biphenyl aralkyl type phenol resin. . A thermally conductive sealing material comprising the epoxy resin composition according to any one of claims 1 to 4. A thermally conductive sheet comprising the epoxy resin composition according to any one of claims 1 to 4. A thermally conductive adhesive composition comprising the epoxy resin composition according to any one of claims 1 to 4. A cured product obtained by hardening an epoxy resin composition according to any one of claims 1 to 4. An epoxy resin composition comprising an epoxy resin selected from a phenyl aralkyl type phenol tree A curing agent composed of one or more phenol resins in a group consisting of a fat and a biphenyl aralkyl type phenol resin, and a magnesium oxide powder. A filler for an epoxy resin composition comprising a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amine group.