JP2005320479A - Liquid epoxy resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid epoxy resin composition which excels in heat conductivity, heat resistance, electrical insulation, workability and the like and is suitable for the insulation treatment of electrical/electronic parts and the like and as an adhesive and the like. <P>SOLUTION: The liquid epoxy resin composition comprises (A) a liquid epoxy resin, (B) a liquid curing agent, (C) spherical aluminum nitride particles having a primary particle diameter of 0.1-1 μm, and (D) spherical aluminum oxide particles having an average particle diameter of ≤50 μm, and has a heat conductivity of a cured product at 25°C of ≥2.5 W/m×K. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a liquid epoxy resin composition, more specifically, a liquid epoxy resin composition excellent in thermal conductivity, heat resistance, electrical insulation, workability, etc., and suitable as an insulation treatment or adhesive for electrical / electronic parts, etc. It is about things.

Epoxy resins have less shrinkage during curing than other thermosetting resins such as unsaturated polyesters and phenolic resins, and cured products have excellent chemical, electrical and mechanical properties. Because of its high adhesive properties, it is used in many fields including the paint field, electrical / electronic field, civil engineering / architecture field.
Among them, in the electric / electronic field, for example, it is used for laminated substrates, semiconductor sealing materials, insulating powder paints, coil impregnation and the like. In particular, there is a great demand for fillers and sealing materials for electronic components accompanying the downsizing of electronic devices. In semiconductor elements, high-density substrates and module parts, liquid sealing materials and fillers are poured into IC chips, resistors, capacitors, etc. mounted on the substrate for stabilization. Yes.
Recently, as the performance of electric / electronic parts increases, the amount of heat generated from the parts tends to increase. Therefore, in order to avoid failure due to overheating of the parts, the epoxy resin composition used for insulation treatment In order to reduce the temperature of parts due to heat dissipation, improvement in the thermal conductivity of the cured product is required.
In addition, the same tendency is seen with the high performance of the engine, especially in the case of a car application for bonding between ceramic and metal parts, and there is a demand for improvement in the thermal conductivity of the cured product. Yes.

As a means of improving the thermal conductivity of the cured product, it is conceivable to highly fill various fillers with high thermal conductivity, but fillers with high thermal conductivity, for example, metals such as gold, silver, copper, etc. There is a problem that it has electrical conductivity and is difficult to use for electrical insulation.
There are many fillers having electrical insulation properties, and among the fillers generally used, aluminum oxide is known as one having excellent thermal conductivity and electrical insulation properties. However, in the aluminum oxide crushed powder, when blended in a large amount in the epoxy resin composition, the viscosity of the composition increases remarkably, so that the blended amount of the crushed powder is limited to maintain good workability. I can not escape. In addition, since the aluminum oxide powder has high hardness, there is a problem in workability such as increased wear of the manufacturing equipment in the crushed shape.
Furthermore, the true specific gravity of aluminum oxide is as large as 3.9 at 25 ° C., and there is a concern of sedimentation during long-term storage in a liquid composition.

  On the other hand, as an insulating adhesive composition having high thermal conductivity and excellent adhesion between the metal substrate and the insulating layer, aluminum nitride powder having a particle diameter of 10 to 45 μm is 42.5 to 76.0 mass on the epoxy resin. %, A resin composition containing 17.0 to 47.5 mass% of spherical aluminum oxide powder having a maximum particle size of 3 μm or less is disclosed (for example, see Patent Document 1). However, this resin composition has the disadvantages that since the particle size of the aluminum nitride powder is large, it tends to settle and the workability is poor.

JP 2002-322372 A

  Under such circumstances, the present invention provides a liquid epoxy resin composition that is excellent in thermal conductivity, heat resistance, electrical insulation, workability, and the like, and is suitable as an insulation treatment or adhesive for electrical / electronic parts. It is intended to provide.

As a result of extensive research to develop a liquid epoxy resin composition having the above-mentioned excellent properties, the present inventors have obtained a liquid epoxy resin, a liquid curing agent, and spherical aluminum nitride particles having a specific particle diameter, It has been found that the object can be achieved by a liquid epoxy resin composition containing spherical aluminum oxide particles having an average particle diameter of a certain value or less and having a thermal conductivity of a certain value or more. The present invention has been completed based on such findings.
That is, the present invention
(1) (A) liquid epoxy resin, (B) liquid curing agent, (C) spherical aluminum nitride particles having a primary particle diameter of 0.1 to 1 μm, and (D) spherical aluminum oxide particles having an average particle diameter of 50 μm or less. And a liquid epoxy resin composition characterized in that the cured product has a thermal conductivity of 2.5 W / m · K or more at 25 ° C.,
(2) The total volume content of spherical aluminum nitride particles of component (C) and spherical aluminum oxide particles of component (D) is 60 vol% or more, and the viscosity at a temperature of 25 ° C. is 100 Pa · s or less (1 (1) or (2), wherein the liquid epoxy resin composition according to item (3) and (3) the cured product have a glass transition point of 120 ° C. or higher and a dielectric breakdown strength of 15 MV / m or higher at 25 ° C. ) Liquid epoxy resin composition according to item
Is to provide.

  According to the present invention, it is possible to provide a liquid epoxy resin composition that is excellent in thermal conductivity, heat resistance, electrical insulation, workability, and the like, and that is suitable as an insulation treatment or adhesive for electrical / electronic parts. .

The liquid epoxy resin composition of the present invention is a liquid composition containing (A) a liquid epoxy resin, (B) a liquid curing agent, (C) spherical aluminum nitride particles and (D) spherical aluminum oxide particles.
The liquid epoxy resin as the component (A) is not particularly limited as long as it is a compound having two or more epoxy groups in one molecule, and is arbitrary from known compounds conventionally used as epoxy resins. Can be selected and used. Examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, glycidyl ethers of polycarboxylic acids, and epoxy resins obtained by epoxidation of cyclohexane derivatives. These may be used individually by 1 type, and may be used in combination of 2 or more types. In addition, these epoxy resins can be appropriately used in combination with a reactive diluent having an epoxy group, if necessary, for the purpose of adjusting the viscosity of the composition or improving the physical properties of the cured product. Among the epoxy resins, from the viewpoints of heat resistance and workability, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and epoxy resins obtained by epoxidation of cyclohexane derivatives are suitable.

The liquid curing agent of the component (B) is not particularly limited as long as it is a liquid that is usually used as a curing agent for an epoxy resin, and can be arbitrarily selected from conventionally known liquid curing agents for epoxy resins. Can be selected and used. Among these liquid curing agents, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, m-xylylenediamine, diaminodiphenylmethane adduct are used from the viewpoint of heat resistance and workability. Aromatic amines such as modified aromatic amines and adducts thereof are preferred. One of these liquid curing agents may be used alone, or two or more thereof may be used in combination.
In the present invention, the amount of the component (B) liquid curing agent used depends on the epoxy equivalent of the component (A) liquid epoxy resin and the type of the curing agent, but the component (A) component liquid epoxy resin 100. It is normally selected in the range of 10 to 150 parts by mass, preferably 20 to 120 parts by mass with respect to parts by mass.

  In the present invention, a curing accelerator can be used in combination with the liquid curing agent of the component (B) if desired. There is no restriction | limiting in particular as this hardening accelerator, From the things conventionally used as a hardening accelerator of an epoxy resin, arbitrary things can be selected and used suitably. For example, imidazoles such as 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, etc. Examples thereof include compounds, 2,4,6-tris (dimethylaminomethyl) phenol, boron trifluoride amine complex, and triphenylphosphine. These hardening accelerators may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of the curing accelerator used is usually about 0.1 to 10 parts by mass, preferably about 100 to 10 parts by mass, preferably 100 parts by mass of the liquid epoxy resin of the component (A), from the viewpoint of balance between curing acceleration and cured resin properties. It is selected in the range of 0.5 to 5 parts by mass.

Next, as the (C) component spherical aluminum nitride particles in the present invention, those having a primary particle diameter in the range of 0.1 to 1 μm are used. When the primary particle diameter is in the above range, thixotropy can be imparted to the liquid resin composition, so that an anti-settling effect of each filler can be expected.
The aluminum nitride particles have a significantly higher thermal conductivity than the aluminum oxide particles, and the true specific gravity is 3.3 at 25 ° C. Therefore, the aluminum nitride particles are smaller than the aluminum oxide 3.9 and settle. It has the feature of being difficult. In addition, the said primary particle diameter is the value measured by observing with a magnification of 6000 time with an electron microscope.
Moreover, since this aluminum nitride particle is spherical, it is suitable for high filling. Spherical aluminum nitride having such a primary particle size is available, for example, as high-purity aluminum nitride “Grade H” [trade name, manufactured by Tokuyama Corporation].
In the present invention, the content of the spherical aluminum nitride particles of the component (C) is the liquid content of the component (A) from the viewpoint of thermal conductivity, electrical insulation, workability, and other physical properties of the liquid epoxy resin composition. It is normally selected in the range of about 100 to 500 parts by mass, preferably 100 to 300 parts by mass with respect to 100 parts by mass of the epoxy resin.

Furthermore, as the spherical aluminum oxide particles of the component (D) in the present invention, those having an average particle diameter of 50 μm or less are used. If this average particle diameter is 50 μm or less, it is difficult to settle in the liquid epoxy resin composition, and when the composition is used as an adhesive, aluminum oxide particles protrude from the coating film at a desired coating film thickness. And good adhesiveness can be obtained. Although there is no restriction | limiting in particular about the minimum of this average particle diameter, Usually, it is about 1 micrometer from a practical surface. Examples of spherical aluminum oxide having an average particle diameter of 50 μm or less are available as “DAW-05”, “DAW-45”, “DAB-10SI” [all trade names, manufactured by Denka Co., Ltd.], and the like. . These may be used alone or in combination of two or more.
In the present invention, the content of the spherical aluminum oxide particles of the component (D) is the liquid content of the component (A) from the viewpoint of thermal conductivity, electrical insulation, workability, and other physical properties of the liquid epoxy resin composition. It is normally selected in the range of about 100 to 1500 parts by mass, preferably 600 to 1200 parts by mass with respect to 100 parts by mass of the epoxy resin.

  In the liquid epoxy resin composition of the present invention, the cured product has a thermal conductivity of 2.5 W / m · K or more at 25 ° C. and high thermal conductivity. Although there is no restriction | limiting in particular about the upper limit of this heat conductivity, Usually, it is about 4 W / m * K.

Moreover, in the liquid epoxy resin composition of the present invention, the glass transition point of the cured product is usually 120 ° C. or higher and excellent in heat resistance, and the strength of dielectric breakdown is usually 15 MV / at 25 ° C. m or more, and excellent in electrical insulation. Although there is no restriction | limiting in particular about the upper limit of the glass transition point of hardened | cured material, A glass transition point is 150 degrees C or less normally. The glass transition point is a value measured by the TMA method.
Moreover, although there is no restriction | limiting in particular about the upper limit of the dielectric breakdown strength of hardened | cured material, Usually, it is about 30MV / m at 25 degreeC. The strength of this dielectric breakdown is a value measured for a 1 mm plate test piece based on JIS C2105.

Further, in the liquid epoxy resin composition of the present invention, the total volume content of the spherical aluminum nitride particles (C) and the spherical aluminum oxide particles (D) is usually 60 vol% or more, preferably 60 to 75 vol. %. The viscosity at a temperature of 25 ° C. is preferably 100 Pa · s or less from the viewpoint of workability. The lower limit of the viscosity is not particularly limited, but is usually about 10 Pa · s at a temperature of 25 ° C.
The total volume content of the component (C) and the component (D) is calculated from the true specific gravity of each component at 25 ° C.
Further, the viscosity of the composition is a value measured at 25 ° C. using a Brookfield viscometer under the conditions of # 25 spindle and 3 rpm.

In the liquid epoxy resin composition of the present invention, additives such as a coupling agent, an antifoaming agent, a pigment, a dispersing / wetting agent, a flame retardant, and the like are appropriately blended, as long as the object of the present invention is not impaired can do.
There is no restriction | limiting in particular about the preparation method of the liquid epoxy resin composition of this invention, The above-mentioned (A) component, (B) component, (C) component, (D) component, and the reactive diluent and various used as needed The additives can be prepared by mixing them uniformly in a predetermined ratio.
In this case, examples of the mixer to be used include a commonly used change can mixer, planetary mixer, disper, Henschel mixer, kneader, ink roll, and extruder.
The liquid epoxy resin composition of the present invention thus obtained is excellent in thermal conductivity, heat resistance, electrical insulation, workability, etc., especially as an insulation treatment or adhesive for electrical / electronic parts, etc. It is suitably used for coil impregnation casting.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the various characteristics of the liquid epoxy resin composition obtained by each example were measured in accordance with the method shown below.
(1) Thermal conductivity of cured product Measured using a thermal conductivity meter QTM-500 manufactured by Kyoto Electronics Industry Co., Ltd.
(2) Glass transition point of cured product Measured by TMA method.
(3) Strength of dielectric breakdown of cured product Based on JIS C2105, a 1 mm plate test piece is measured at 25 ° C.
(4) Filler volume content Measured according to the method described in the specification.
(5) Viscosity of the composition Using a Brookfield viscometer, the viscosity at a temperature of 25 ° C. is measured under the conditions of # 25 spindle and 3 rpm.
(6) Sedimentability of filler in the composition After preparing the composition, when 24 hours have passed at 25 ° C., the bottom of the container is scratched and checked.

Example 1
100 parts by mass of bisphenol A diglycidyl ether (epoxy equivalent 190) as a liquid epoxy resin, 100 parts by mass of methylhexahydrophthalic anhydride as a liquid curing agent, 1 part by mass of 1-benzyl-2-methylimidazole as a curing accelerator , High-purity aluminum nitride powder [manufactured by Tokuyama Co., Ltd., trade name “Grade H”, spherical, primary particle size 0.1 to 1 μm] 300 parts by mass, aluminum oxide powder 1 [manufactured by Denka Co., Ltd., trade name “DAW-05”, spherical, average particle size 4.8 μm] 466 parts by mass, aluminum oxide powder 2 [Denka Co., Ltd., trade name “DAW-45”, spherical, average particle size 44.5 μm] 466 parts by mass , Epoxy silane coupling agent [GE Toshiba Silicone Co., Ltd., trade name “TSL8350”] 3 parts by mass, antifoaming agent [GE Toshiba Silicone Co., Ltd., trade name “TSA720”] 0.3 parts by mass and a dispersing / wetting agent [manufactured by Big Chemie, trade name “BYK-9010”] 1 part by weight are homogeneously mixed to obtain a liquid epoxy resin composition. Prepared.
The evaluation results of various properties of this liquid epoxy resin composition are shown in Table 1. In addition, hardening in hardened | cured material preparation was first performed at 100 degreeC for 3 hours, and then at 150 degreeC for 3 hours. (The same applies hereinafter).

Comparative Example 1
100 parts by mass of bisphenol A diglycidyl ether (epoxy equivalent 190) as a liquid epoxy resin, 100 parts by mass of methylhexahydrophthalic anhydride as a liquid curing agent, 1 part by mass of 1-benzyl-2-methylimidazole as a curing accelerator , Aluminum oxide crushed product [manufactured by Sumitomo Chemical Co., Ltd., trade name “AL-33”, average particle size 12 μm] 1200 parts by mass, epoxy silane coupling agent [GE Toshiba Silicone Co., Ltd., trade name “TSL8350” ] 3 parts by mass, defoaming agent [GE Toshiba Silicone Co., Ltd., trade name “TSA720”] 0.3 part by mass and dispersing / wetting agent [Big Chemie, trade name “BYK-9010”] 1 part by weight The liquid epoxy resin composition was prepared by mixing homogeneously.
Table 1 shows the evaluation results of various properties of this liquid epoxy resin composition.

Comparative Example 2
100 parts by mass of bisphenol A diglycidyl ether (epoxy equivalent 190) as a liquid epoxy resin, 100 parts by mass of methylhexahydrophthalic anhydride as a liquid curing agent, 1 part by mass of 1-benzyl-2-methylimidazole as a curing accelerator Aluminum oxide powder 1 [Denka Co., Ltd., trade name “DAW-05”, spherical, average particle size 4.8 μm] 600 parts by mass, Aluminum oxide powder 2 [Denka Co., Ltd., trade name “DAW-45” ”, Spherical, average particle diameter 44.5 μm] 600 parts by mass, epoxy silane coupling agent [GE Toshiba Silicone Co., Ltd., trade name“ TSL8350 ”], 3 parts by mass, antifoaming agent [GE Toshiba Silicone Co., Ltd. , Trade name “TSA720”] 0.3 parts by mass and dispersing / wetting agent [manufactured by Big Chemie, trade name “BYK-9010”] 1 A mass part was homogeneously mixed to prepare a liquid epoxy resin composition.
The evaluation results of various properties of this liquid epoxy resin composition are shown in Table 1.

Comparative Example 3
100 parts by mass of bisphenol A diglycidyl ether (epoxy equivalent 190) as a liquid epoxy resin, 100 parts by mass of methylhexahydrophthalic anhydride as a liquid curing agent, 1 part by mass of 1-benzyl-2-methylimidazole as a curing accelerator , Aluminum oxide powder 1 [Denka Co., Ltd., trade name “DAW-05”, spherical, average particle size 4.8 μm] 778 parts by mass, aluminum oxide powder 2 [Denka Co., Ltd., trade name “DAW-45” ”, Spherical, average particle diameter 44.5 μm] 778 parts by mass, epoxy silane coupling agent [GE Toshiba Silicone Co., Ltd., trade name“ TSL8350 ”], 3 parts by mass, antifoaming agent [GE Toshiba Silicone Co., Ltd. , Trade name “TSA720”] 0.3 parts by mass and dispersing / wetting agent [manufactured by Big Chemie, trade name “BYK-9010”] 1 A liquid epoxy resin composition was prepared by homogeneously mixing parts by mass.
Table 1 shows the evaluation results of various properties of this liquid epoxy resin composition.

  As can be seen from Table 1, the liquid epoxy resin composition of the present invention (Example 1) is excellent in thermal conductivity, heat resistance and electrical insulation, has a low viscosity, and has no sedimentation of the filler. It has good workability, and its cast products such as electric and electronic parts are highly reliable.

The liquid epoxy resin composition of the present invention is excellent in thermal conductivity, heat resistance, electrical insulation, workability and the like, and is suitably used as an insulation treatment or an adhesive for electrical / electronic parts.

Claims (3)

  (A) liquid epoxy resin, (B) liquid curing agent, (C) spherical aluminum nitride particles having a primary particle diameter of 0.1 to 1 μm, and (D) spherical aluminum oxide particles having an average particle diameter of 50 μm or less, And the liquid epoxy resin composition characterized by the heat conductivity of hardened | cured material being 2.5 W / m * K or more at 25 degreeC.   The total volume content of the spherical aluminum nitride particles of component (C) and the spherical aluminum oxide particles of component (D) is 60 vol% or more, and the viscosity at a temperature of 25 ° C is 100 Pa · s or less. Liquid epoxy resin composition. The liquid epoxy resin composition according to claim 1 or 2, wherein the cured product has a glass transition point of 120 ° C or higher and a dielectric breakdown strength of 15 MV / m or higher at 25 ° C.