JP2015059130A - Epoxy resin composition, use thereof and filler for epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally conductive epoxy resin composition containing a magnesium oxide powder, which can be easily prepared by kneading, is improved in fluidity and excellent in moldability and has good water absorbing property (low water absorption property), and preferably to provide a thermally conductive epoxy resin composition further containing a magnesium oxide powder excellent in flame retardancy, the epoxy resin composition being capable of being suitably used as a thermally conductive sealing material, a thermally conductive sheet, a thermally conductive adhesive and a cured product.SOLUTION: There is provided an epoxy resin composition which comprises an epoxy resin, a curing agent and a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amino group.

Description

  The present invention contains a thermally conductive epoxy resin composition containing magnesium oxide powder, and a thermally conductive sealing material, a thermally conductive sheet, a thermally conductive adhesive, a cured product, and magnesium oxide powder comprising the same. The present invention relates to a filler for an epoxy resin composition. In particular, it can be easily prepared by kneading, has improved flowability, excellent moldability, good water absorption (low water absorption), and preferably has excellent heat resistance and excellent combustion resistance. The present invention relates to an epoxy resin composition.

Epoxy resin compositions are used for various applications in many fields.
Particularly in electronic components, it is suitably used as a substrate material, a sealing material, a heat conductive sheet material, an adhesive, and the like. In this application, the amount of heat generated from electronic components tends to increase with progress in miniaturization, high integration, high capacity, high speed, and the like. As the amount of heat generation increases, the reliability of electronic components decreases due to the influence of temperature and humidity. For this reason, in addition to heat resistance and low water absorption (humidity resistance), it is required to impart thermal conductivity to the epoxy resin composition in order to improve heat dissipation.
In addition, in the case of adhesives and coating materials, flame retardancy is not necessarily required, but in the case of directly sealing a heat source such as a semiconductor encapsulating material, it is used for electronic components in consideration of safety. A high degree of combustion resistance is required.

  In order to impart thermal conductivity to the epoxy resin composition, it has already been proposed to add magnesium oxide. Magnesium oxide improves thermal conductivity. However, if the blending amount is increased, the fluidity is lowered and the moldability is not sufficient, so that there is a problem in the moldability especially in an electronic component that is downsized (thinned, miniaturized, complicated).

Patent Document 1 proposes a resin composition containing magnesium oxide powder excellent in moisture resistance and thermal conductivity. Here, when magnesium oxide is surface-treated with an inorganic coupling agent such as silane, the treatment agent surface-treated in the kneading operation step with the resin is easy to peel off from the surface of the magnesium oxide, lacks mechanical strength, and the surface is There is a description that it will not be put to practical use because a whitening phenomenon occurs due to a hydration reaction to change to magnesium hydroxide. Here, coated magnesium oxide having a coating layer containing a double oxide of silicon and magnesium and / or a double oxide of aluminum and magnesium on the surface is used.
Patent Document 2 proposes an epoxy resin composition with improved thermal conductivity (heat dissipation) in which magnesium oxide powder and silicon dioxide powder are blended at a specific volume ratio. Here, it is described that the surface of magnesium oxide is treated with a silane coupling agent, and in the examples, magnesium oxide treated with oligomeric reactive siloxane is used. However, detailed investigations have not been made on ordinary (compound type) silane coupling agents.

JP 2004-27177 A JP 2012-162650 A

  The object of the present invention is that it can be easily prepared by kneading, has improved flowability, excellent moldability, good water absorption (low water absorption), and heat conductivity containing magnesium oxide powder An epoxy resin composition is provided. Moreover, the objective of this invention is providing the heat conductive epoxy resin composition containing the magnesium oxide powder which is preferably excellent in combustion resistance further. The epoxy resin composition of this invention can be used conveniently as a heat conductive sealing material, a heat conductive sheet, a heat conductive adhesive, and hardened | cured material.

The present invention relates to the following matters.
1. An epoxy resin composition comprising magnesium oxide powder surface-treated with an epoxy resin, a curing agent, and an alkoxysilane having at least one of a phenyl group and an amino group.
2. Item 2. The epoxy resin composition according to Item 1, wherein the alkoxysilane is a compound represented by the following chemical formula (1).

化学式（１）において、ｌは１〜３の整数、Ｒはそれぞれ同一又は異なっていてもよいアルキル基、Ｒ’はそれぞれ同一又は異なっていてもよいフェニル基及びアミノ基のうちの少なくとも一方を含む一価の基である。

In the chemical formula (1), l is an integer of 1 to 3, R is an alkyl group that may be the same or different, and R ′ includes at least one of a phenyl group and an amino group that may be the same or different. It is a monovalent group.

3. Item 3. The epoxy resin composition according to Item 1 or 2, wherein the curing agent is a phenol resin.
4). Item 4. The epoxy resin composition according to Item 3, wherein the phenol resin is one or more phenol resins selected from the group consisting of phenyl aralkyl type phenol resins and biphenyl aralkyl type phenol resins.
5. The heat conductive sealing material which consists of an epoxy resin composition in any one of said items 1-4.
6). The heat conductive sheet which consists of an epoxy resin composition in any one of said items 1-4.
7). The heat conductive adhesive which consists of an epoxy resin composition in any one of said items 1-4.
8). Hardened | cured material which hardened the epoxy resin composition in any one of said claim | item 1-4.
9. An epoxy resin composition comprising: a curing agent composed of one or more phenolic resins selected from the group consisting of an epoxy resin, a phenylaralkyl-type phenolic resin, and a biphenylaralkyl-type phenolic resin; and magnesium oxide powder.
10. An epoxy resin composition filler comprising a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amino group.

  According to the present invention, heat conductivity containing magnesium oxide powder, which can be easily prepared by kneading, has improved flowability, excellent moldability, and good water absorption (low water absorption). The epoxy resin composition can be provided. In addition, according to the present invention, it is possible to provide a heat conductive epoxy resin composition containing a magnesium oxide powder that is preferably excellent in combustion resistance. The epoxy resin composition of this invention can be used conveniently as a heat conductive sealing material, a heat conductive sheet, a heat conductive adhesive, and hardened | cured material.

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

  The epoxy resin of the epoxy resin composition of the present invention is not particularly limited as long as it contains two or more epoxy groups in the molecule. For example, bisphenol type, phenol novolak type, cresol novolak type, biphenyl type Suitable examples include epoxy resins such as triphenylmethane type, dicyclopentadiene type, and naphthol type. These epoxy resins may be used alone or in combination. Among these epoxy resins, cresol novolac type epoxy resins and biphenyl type epoxy resins are particularly suitable.

The curing agent of the epoxy resin composition of the present invention is not particularly limited as long as it can react with the epoxy resin to obtain a cured product, and is typically an amine compound, acid anhydride, or the like used as a curing agent for the epoxy resin. A phenol resin or the like can be preferably used.
The curing agent 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 novolac type phenol resins such as phenol novolak type, cresol novolak type, phenyl aralkyl type, biphenyl aralkyl type, triphenylmethane type, dicyclopentadiene type, and naphthol type. Among them, phenyl aralkyl type phenol resins and biphenyl aralkyl type phenol resins are particularly preferably used because they have low water absorption and can further improve the flame resistance (flame resistance). be able to.

The phenylaralkyl type phenol resin and the biphenyl aralkyl type phenol resin are phenols such as —CH ₂ —Bz—CH ₂ — or —CH ₂ —Bz—Bz—CH ₂ — (Bz: benzene ring). A novolak type phenol resin having a chemical structure bonded with a divalent bridging group (phenyl aralkyl group or biphenyl aralkyl group) containing a phenylene skeleton or a biphenylylene skeleton in the group, preferably the following chemical formulas (2) to (5) More preferably, it has a chemical structure represented by the following chemical formulas (4) to (5).

化学式（２）において、ｎは１以上の整数（好ましくは１〜２０の整数）、Ｒ_１は炭素数が１〜６のアルキル基又は水酸基のいずれか、ｐは０〜２の整数である。

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

化学式（３）において、ｍは１以上の整数（好ましくは１〜２０の整数）、ｎは１以上の整数（好ましくは１〜２０の整数）、Ｒ_１は炭素数が１〜６のアルキル基又は水酸基のいずれか、ｐは０〜２の整数である。

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 either of a hydroxyl group, p is an integer of 0-2.

化学式（４）において、ｎは１以上の整数（好ましくは１〜２０の整数）、Ｒ_１は炭素数が１〜６のアルキル基又は水酸基のいずれか、ｐは０〜２の整数である。

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

化学式（５）において、ｍは１以上の整数（好ましくは１〜２０の整数）、ｎは１以上の整数（好ましくは１〜２０の整数）、Ｒ_１は炭素数が１〜６のアルキル基又は水酸基のいずれか、ｐは０〜２の整数である。

In 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 either of a hydroxyl group, 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, but when the blending amount of the epoxy resin is 100 parts by mass, the curing agent is 50 to 120 parts by mass. A range is preferable.

The magnesium oxide powder used in the epoxy resin composition of the present invention is surface-treated with an alkoxysilane having at least one of a phenyl group and an amino group.
The magnesium oxide powder is not particularly limited, but can be suitably obtained, for example, by heat-treating magnesium hydroxide to about 1400 ° C. or more and less than about 2800 ° C. (melting temperature). In the present invention, a magnesium oxide powder obtained by firing at a temperature of preferably 1600 ° C. or higher and lower than 2600 ° C., more preferably 2000 to 2400 ° C., can be suitably used. The magnesium oxide powder of the present invention is not particularly limited, but the average particle diameter is preferably in the range of 0.5 to 100 μm, more preferably 1 to 80 μm, and the purity is preferably 94.0. It is in the range of 96.0 to 99.7% by mass, more preferably 9% by mass or more.

  The alkoxysilane used for the surface treatment of magnesium oxide used in the present invention is an alkoxysilane (compound, not an oligomer) having a chemical structure containing at least one of a phenyl group and an amino group in the molecule, Preferably, it is an alkoxysilane represented by the following chemical formula (1). In particular, the alkoxysilane preferably contains a phenyl group from the viewpoint of fluidity.

化学式（１）において、ｌは１〜３の整数、Ｒはそれぞれ同一又は異なっていてもよいアルキル基（好ましくは炭素数が１〜６のアルキル基、より好ましくはメチル基又はエチル基）、Ｒ’はそれぞれ同一又は異なっていてもよいフェニル基及びアミノ基のうちの少なくとも一方を含む一価の基である。

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

  As specific examples of such alkoxysilanes, preferred are the compounds represented by the following chemical formula (6).

  In addition, although the processing amount of alkoxysilane is not specifically limited, Preferably it is 0.01-10 mass% with respect to magnesium oxide powder, More preferably, it is a ratio of 0.05-5 mass%.

  In the present invention, by using magnesium oxide whose surface is treated with an alkoxysilane having at least one of a phenyl group and an amino group, it can be easily prepared by kneading, and the fluidity at the time of molding (spiral) Flow) is improved, and a heat conductive epoxy resin composition having excellent moldability and low water absorption can be obtained.

  The surface treatment method of the magnesium oxide powder is not particularly limited, but the surface treatment can be performed using, for example, a dry reaction method or a wet reaction method. The dry reaction method is a method in which magnesium oxide powder is charged into a device capable of high-speed stirring such as a Henschel mixer, and alkoxysilane or an alkoxysilane hydrolyzate is added while stirring. As the addition method, a method capable of uniformly reacting alkoxysilane is desirable, and a known method, for example, a method of gradually dropping, a method of spraying in a mist, a method of introducing gaseous silane, or the like is used. Can do. The wet reaction method is a method in which magnesium oxide powder is reacted in a state dispersed in an alkoxysilane solution, and then dried if necessary. As the solvent to be used, water, alcohol or a mixture thereof is preferable.

Magnesium oxide powder may be used alone or in combination with other inorganic fillers.
The blending ratio of the inorganic filler containing the magnesium oxide powder is 10% to 95%, preferably 30% to 90%, more preferably 60% to 75% in volume% with respect to the total epoxy resin composition. Examples of the inorganic filler other than the magnesium oxide powder used in combination include silicon dioxide, alumina, aluminum nitride, silicon nitride, calcium carbonate, talc, mica, barium sulfate, etc. Among them, it is preferable to use silicon dioxide powder. . The blending ratio with the other inorganic filler used together with the magnesium oxide powder is a volume ratio [magnesium oxide powder: other inorganic filler used together], preferably 100: 0 to 5:95, more preferably 60:40. -5: 95, more preferably 40: 60-25: 75.

In the epoxy resin composition of the present invention, in addition to the inorganic filler containing an epoxy resin, a curing agent, and magnesium oxide powder, various components used in a normal epoxy resin composition can 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 normal epoxy resin composition can be used, but when a phenol resin is used as the curing agent, it may be a compound that activates the hydroxyl group of the phenol resin. desirable. Preferable examples of the curing accelerator include amine compounds such as benzyldimethylamine, triethanolamine, and dimethylaminoethanol, and organic phosphorus compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, and diphenylphosphine. The compounding amount of the curing accelerator is preferably 0.1 to 10 parts by mass, more preferably 1 to 7 parts by mass with respect to 100 parts by mass of the epoxy resin.

Furthermore, in the epoxy resin composition of the present invention, other various additives can be used depending on the application. For example, a release agent, a colorant, a flame retardant, a low stress agent, and the like can be used for a heat conductive sealing material. In a heat conductive sheet, a tackifier, an antiaging agent, a softening agent (for example, Naphthenic oils, paraffinic oils, etc.), thixotropic agents (such as montmorillonite), lubricants (such as stearic acid), pigments, scorch inhibitors, stabilizers, antioxidants, UV absorbers, colorants, antifungal agents A foaming agent or the like can be used, and a pigment, an ultraviolet absorber, or the like can be used for a heat conductive adhesive.
That is, the epoxy resin composition of the present invention can be suitably used as a heat conductive sealing material, a heat conductive sheet, and a heat conductive adhesive.

  Moreover, the epoxy resin composition of this invention can raise | generate a hardening reaction by heat-processing, and can form hardened | cured material. 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, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these Examples.

The kneading step for preparing the epoxy resin composition was evaluated by the following method.
(1) Kneadability A predetermined amount of epoxy resin, a phenolic resin as a curing agent, and magnesium oxide powder and silicon dioxide powder as fillers are kneaded at a predetermined temperature using a biaxial kneader, and discharged from the discharge port of the biaxial kneader. The discharged kneaded material was visually evaluated. As a criterion for evaluation, ○: kneading was possible without any problem Δ: kneading was possible, but kneaded material was non-uniform ×: kneading was not possible.

Moreover, the following method evaluated the epoxy resin composition. The evaluation was performed by molding the epoxy resin composition powder into a tablet and using the tablet as a sample. The tablet was molded by pressing with a hand press at a pressure of 450 MPa for 1 minute.
(2) Formability The molded body was molded using a transfer molding machine at a mold temperature of 175 ° C. and an injection pressure of 6.9 MPa for 30 seconds and then pressurized at 3.0 MPa for 70 seconds. Molded. As a standard for evaluation of moldability, ○: Moldable without problems ×: Cannot be molded.
(3) Fluidity (spiral flow)
The spiral flow value of the sample was measured using a transfer molding machine and a spiral flow measurement mold (based on EMMI-1-66). The mold temperature was 175 ° C., the injection pressure was 6.9 MPa, and after pressurizing for 60 seconds, the fluidity was evaluated under the condition of holding for 40 seconds.

Moreover, about the hardened | cured material of the epoxy resin composition, it evaluated by the following method.
(4) Water absorption (water absorption)
The sample was molded into a disk shape having a thickness of 3 mm and a diameter of 50 mm with a transfer molding machine, and then cured at 180 ° C. for 8 hours to obtain a test piece (cured product). The obtained test piece, weight (W ₁₎ was measured, and held for 24 hours in pure water heated to a temperature of 95 ° C., then after wiping off water removed from the pure water, its mass (W ₂ ) Was measured. The amount of water absorption was calculated from the following formula.
Water absorption (g / cm ³ ) = {W ₂ (g) −W ₁ (g)} / volume of test piece (cm ³ )
(5) Flame resistance (combustion resistance)
The sample was molded into a shape of 1 mm thickness × 13 mm width × 127 mm length by a transfer molding machine, and then cured at 180 ° C. for 8 hours to obtain a test piece (cured product). About the obtained test piece, the flame retardance was evaluated according to UL-94 test method.
(6) Thermal conductivity The sample was molded into a shape of 4 mm thick × 50 mm wide × 100 mm long by a transfer molding machine, and then cured at 180 ° C. for 8 hours to obtain a cured product. The obtained cured product was cut into a shape of 4 mm thickness × 25 mm width × 25 mm length to obtain a test piece. The thermal conductivity of the test piece was measured using a thermal conductivity measuring device GH-1 manufactured by ULVAC.

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: 186 g / eq, viscosity: 0.2 P / 150 ° C., melting point: 105 ° C. (DSC method)

(B) Curing agent (b1) Curing agent 1
Phenol formaldehyde type phenol resin represented by the following chemical formula (7), hydroxyl equivalent: 107 g / eq, viscosity: 2.0 P / 150 ° C., softening point: 84 ° C.

化学式（７）において、ｎは１以上の整数である。

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

(B2) Curing agent 2
Biphenyl aralkyl type phenol resin represented by the following chemical formula (8), hydroxyl group equivalent: 201 g / eq, viscosity: 0.8 P / 150 ° C., softening point: 67 ° C.

化学式（８）において、ｎは１以上の整数である。

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

(B3) Curing agent 3
Biphenyl aralkyl type phenol resin represented by the following chemical formula (9), hydroxyl group equivalent: 166 g / eq, viscosity: 0.5 P / 150 ° C., softening point: 62 ° C.

化学式（９）において、ｍは１以上の整数、ｎは１以上の整数である。

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

(C) Curing accelerator Triphenylphosphine manufactured by Hokuko Chemical Co., Ltd.

(D) Magnesium oxide powder Magnesium oxide powder was manufactured by baking and classifying magnesium hydroxide at 2000 ° C with a rotary kiln. The surface treatment with alkoxysilane was performed by adding 0.5% by mass with respect to magnesium oxide using a high-speed fluidized stirrer and heating and stirring at 120 ° C. for 10 minutes.
(D1) Magnesium oxide powder 1
Magnesium oxide powder whose surface is treated with phenyltrimethoxysilane, average particle size: 5.5 μm
(D2) Magnesium oxide powder 2
Magnesium oxide powder whose surface is treated with N-2-aminoethyl-3-aminopropyltrimethoxysilane, average particle size: 6.1 μm
(D3) Magnesium oxide powder 3
Magnesium oxide powder whose surface is treated with 3-glycidoxypropyltrimethoxysilane, average particle size: 6.8 μm
(D4) Magnesium oxide powder 4
Magnesium oxide whose surface is treated with vinyltrimethoxysilane, average particle size: 6.2 μm
(D5) Magnesium oxide powder 5
Magnesium oxide powder whose surface is not treated, average particle size: 6.5 μm

(E) Silicon dioxide powder MSR-2212 manufactured by Tatsumori Co., Ltd., average particle size: 25 μm

[Example 1]
As shown in Table 1, epoxy resin YX-4000 100 g (100 parts by mass), curing agent curing agent 1 (phenol formaldehyde type phenol resin) 57 g (57 parts by mass), curing accelerator triphenylphosphine 2.7 g ( 2.7 parts by mass), 532 g (532 parts by mass) of silicon dioxide powder (MSR-2212) as a filler, and 424 g (424 parts by mass) of magnesium oxide powder 1 whose surface was treated with phenyltrimethoxysilane. A kneaded product of the epoxy resin composition was obtained by kneading under the temperature conditions shown in Table 1 using a shaft kneader. The kneading process at that time was observed.
The obtained kneaded product was cooled to room temperature and then pulverized using a pulverizer to form a powder. This powder was pressure-molded with a predetermined mold to mold a tablet made of an epoxy resin composition. Using this tablet as a sample, fluidity (spiral flow) was evaluated. Further, the sample was formed into a predetermined size by a transfer molding machine and cured at 180 ° C. for 8 hours to prepare a test piece (cured product) having a predetermined size.

[Example 2]
As shown in Table 1, instead of the curing agent 1 (phenol formaldehyde type phenol resin) of the curing agent, the curing agent 2 (biphenyl aralkyl type phenol resin) was used in the same manner as in Example 1 to determine the epoxy resin composition. A kneaded product was obtained. Moreover, the evaluation was performed.

Example 3
As shown in Table 1, in place of magnesium oxide powder 1, magnesium oxide powder 2 whose surface was treated with N-2-aminoethyl-3-aminopropyltrimethoxysilane was used in the same manner as in Example 2. A kneaded product of the epoxy resin composition was obtained. Moreover, the evaluation was performed.

Example 4
As shown in Table 1, in place of the curing agent 1 (phenol formaldehyde type phenol resin) of the curing agent, the curing agent 3 (biphenyl aralkyl type phenol resin) was used and the epoxy resin composition was treated in the same manner as in Example 1. A kneaded product was obtained. Moreover, the evaluation was performed.

[Comparative Example 1]
As shown in Table 1, an epoxy resin composition kneaded product was obtained in the same manner as in Example 1 using only silicon dioxide powder. Moreover, the evaluation was performed.

[Comparative Example 2]
As shown in Table 1, in place of the magnesium oxide powder 1, using the magnesium oxide powder 3 whose surface was treated with 3-glycidoxypropyltrimethoxysilane, the epoxy resin composition was treated in the same manner as in Example 1. A kneaded product was obtained. Moreover, the evaluation was performed.

[Comparative Example 3]
As shown in Table 1, an epoxy resin composition kneaded material was obtained in the same manner as in Example 1 except that the magnesium oxide powder 4 whose surface was treated with vinyltrimethoxysilane was used instead of the magnesium oxide powder 1. . Moreover, the evaluation was performed.

[Comparative Example 4]
As shown in Table 1, instead of magnesium oxide powder 1, an attempt was made to obtain a kneaded product of an epoxy resin composition in the same manner as in Example 1 by using magnesium oxide powder 5 whose surface was not treated. Could not get.

[Reference Example 1]
As shown in Table 1, a kneaded product of an epoxy resin composition was obtained in the same manner as in Example 2 using magnesium oxide powder 4 whose surface was treated with vinyltrimethoxysilane instead of magnesium oxide powder 1. . Moreover, the evaluation was performed.

[Reference Example 2]
As shown in Table 1, an epoxy resin composition kneaded product was obtained in the same manner as in Example 2 using magnesium oxide powder 5 whose surface was not treated instead of magnesium oxide powder 1. Moreover, the evaluation was performed.

  Table 1 shows the compositions and evaluation results of Examples and Comparative Examples.

  As shown in Table 2, Example 1 using magnesium oxide powder 1 has improved kneadability as compared with Comparative Examples 2 to 4 using magnesium oxide powders 3 to 5, and particularly improved flowability and molding. It can be seen that an epoxy resin composition having excellent properties can be obtained.

  As shown in Table 3, in Examples 2 and 3 using magnesium oxide powders 1 and 2, kneadability was improved as compared to Reference Examples 1 and 2 using magnesium oxide powders 4 and 5, and fluidity was further improved. It can be seen that an epoxy resin composition having improved moldability and excellent moldability can be obtained. It can be seen from Example 4 that this effect is also effective in the curing agent 3.

  As shown in Table 4, in Examples 1-4, it turns out that the thermal conductivity is improving rather than the comparative example 1 which does not use magnesium oxide. About a flame retardance, a flame retardance falls by using a magnesium oxide powder so that Example 1 and the comparative example 1 using the hardening | curing agent 1 may show. However, it can be seen that by using the curing agents 2 and 3, flame retardancy is improved and V-0 can be achieved.

  According to the present invention, it is possible to easily prepare by kneading, in particular, the fluidity is improved, the moldability is excellent, the water absorption is good (low water absorption), and the heat conductivity containing the magnesium oxide powder. An epoxy resin composition can be provided. In addition, according to the present invention, it is possible to provide a heat conductive epoxy resin composition containing a magnesium oxide powder that is preferably excellent in combustion resistance. The epoxy resin composition of this invention can be used conveniently as a heat conductive sealing material, a heat conductive sheet, a heat conductive adhesive, and hardened | cured material.

Claims (10)

  An epoxy resin composition comprising magnesium oxide powder surface-treated with an epoxy resin, a curing agent, and an alkoxysilane having at least one of a phenyl group and an amino group. The epoxy resin composition according to claim 1, wherein the alkoxysilane is a compound represented by the following chemical formula (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 at least one of a phenyl group and an amino group which may be the same or different. Including monovalent groups.)   The epoxy resin composition according to claim 1, 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 phenyl aralkyl type phenol resins and biphenyl aralkyl type phenol resins.   The heat conductive sealing material which consists of an epoxy resin composition in any one of Claims 1-4.   The heat conductive sheet which consists of an epoxy resin composition in any one of Claims 1-4.   The heat conductive adhesive which consists of an epoxy resin composition in any one of Claims 1-4.   Hardened | cured material which hardened the epoxy resin composition in any one of Claims 1-4.   An epoxy resin composition comprising: a curing agent composed of one or more phenolic resins selected from the group consisting of an epoxy resin, a phenylaralkyl-type phenolic resin, and a biphenylaralkyl-type phenolic resin; and magnesium oxide powder.   An epoxy resin composition filler comprising a magnesium oxide powder surface-treated with an alkoxysilane having at least one of a phenyl group and an amino group.