JPH0610247B2 - Liquid epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a hybrid I centered on a ceramic substrate.
The present invention relates to a liquid epoxy resin composition for casting and sealing electronic parts such as C, diodes, circuit modules, power transistors, and IC relays.

[Conventional technology]

Moisture resistance and heat cycle resistance are two major characteristics required for sealing materials for electric / electronic components. It is recognized that these are mutually exclusive properties.

In the case of using an epoxy resin composition as a method for improving the heat cycle property, there are two possible methods of imparting flexibility but reducing expansion.

There are various means for imparting flexibility, and a flexible epoxy resin is mainly used.

A flexible curing agent is used.

Although there is such a case that a plasticizer is added to give flexibility, in any means, the moisture resistance is particularly deteriorated with time particularly in the pressure cooker treatment and is not practical.

On the other hand, in order to obtain a composition having a low expansion coefficient, a method of suppressing the thermal expansion of the composition by adding an inorganic filler having a low linear expansion coefficient can be considered. However, in this case, there is a limit to the addition of the inorganic filler, and if the amount of addition is increased, the viscosity becomes high and it is difficult to put it into practical use.

In recent years, demands for reliability of electronic parts have become more severe, and heat cycle resistance of -55 ° C is a necessary characteristic.
/ 150 ° C, and at the same time, the pressure cooker processing time reaches 200 to 500 hours, and an insulating material corresponding thereto is required.

As a method for improving heat cycle resistance, compounding a xylene resin with an epoxy resin (Japanese Patent Application Laid-Open No. 57-17494).
4) is also proposed, which has some improvement in heat cycle resistance, but is still insufficient in pressure cooker resistance.

[Object of the Invention]

As described above, there has been almost no suitable material having a good balance between the pressure cooker resistance and the heat cycle resistance, but the present invention has conducted research to meet the demand, and as a result, xylene resin and aromatic amine have been obtained. Further, by using a specific silicon compound in combination, a liquid epoxy resin composition has been provided as a material having a good balance between heat cycle resistance and pressure cooker resistance.

[Structure of Invention]

The present invention relates to an epoxy resin composition containing an inorganic filler, wherein (a) xylene resin is preferably contained in an amount of 0.1 to 20% by weight, and (b) diaminodiphenylmethane-based amine and other aromatics. A eutectic mixture with a group amine, preferably 0.9 to 1.1 equivalents relative to the epoxy resin and
(c) A liquid epoxy resin composition characterized by containing 0.01 to 5% by weight of the silicone resin represented by the following general formula (1), preferably with respect to the entire composition, and casting an electric / electronic component. It is suitable for sealing.

General formula (1) (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ ,
R ₈ is a methyl group or a phenyl group, of which 2 to 6 are methyl groups and 2 to 6 are phenyl groups. The epoxy resin used in the present invention must be liquid at room temperature, and it is preferable that the epoxy resin can be highly filled with an inorganic filler. Therefore, it has a relatively low viscosity (300 poise
/ 25 ° C. or less), and bisphenol A type and bisphenol F type epoxy resins having a molecular weight of about 350 to 450 are preferable.

Similarly, the curing agent is preferably liquid at room temperature, and is preferably a heat curing type. In the case of the room temperature curing type, the Tg of the cured epoxy resin is low, so that the pressure cooker resistance is inferior.

Among the heat-curable types, they are roughly classified into aromatic amine type and acid anhydride type. When the heat cycle resistances of the two were compared, it was discovered by the present inventors that the acid anhydride system was considerably inferior. The results will be described in the section of Examples. Therefore, aromatic amines are most preferable, and diaminodiphenylmethane type ones are particularly preferable. Specifically, there are diaminodiphenylmethane, diaminodixylylmethane, aminoxylylaminophenylmethane, phenylenediamine, etc., and many of them are solid at room temperature,
It is better to liquefy as a eutectic mixture. As an inorganic filler, it is important to improve heat cycle resistance,
Generally, silica, fused silica, alumina and the like are mentioned, and when impurities are taken into consideration, silica with a small amount thereof is generally preferable.

Silicon resin has a main chain whose repeating unit is a unit in which a silicon atom and an oxygen atom are bonded, and a bond which is not bonded to the oxygen atom of the silicon atom is bonded to a hydrocarbon group such as a methyl group or a phenyl group. It is what

Silicon resin is excellent in electric insulation and heat resistance and has extremely low hygroscopicity, and therefore, the silicon resin is used alone as an insulating sealing material for electric and electronic parts and semiconductors.

However, the silicone resin originally does not show any compatibility with the epoxy resin composition, and therefore various organic groups are bonded to the silicone resin to improve the compatibility with the epoxy resin composition as a modified silicone resin. However, it is unavoidable that the original excellent properties of the silicone resin are lost by such modification.

The present inventors have found that when the molecular weight of the silicone resin and the hydrocarbon group bonded to the silicon atom are in a particularly limited range, the silicone resin has good compatibility with the epoxy resin composition. That is, when the repeating unit of the silicone resin is trisiloxane, which is a trimer, and the total of 8 hydrocarbon groups is 2 to 6 methyl groups and 6 to 2 phenyl groups, It has good compatibility with the epoxy resin composition, and this specially limited silicone resin retains the excellent properties of the silicone resin with respect to the epoxy resin composition, while having good heat cycle property and pressure cooker resistance. It exerts an improved hardening. The content of the silicone resin is 0.01 with respect to the entire epoxy resin composition.
-5% by weight is suitable. More preferably, 0.3-
It is 3.5% by weight. If the content is less than 0.01% by weight, the compounding effect will not be exhibited.

On the other hand, if the content exceeds 5% by weight, defects as a non-reactive plasticizer such as embossing of silicone resin appear.

The xylene resin used in the present invention is preferably liquid at room temperature. As the molecular weight increases, compatibility with the liquid epoxy resin deteriorates, and heat cycle resistance tends to be insufficiently improved. Therefore,
The xylene resin preferably has a molecular weight of 300 to 500. Specifically, Mitsubishi Gas Chemical Co., Ltd.'s xylene resin "Nicanol" L,
LL, LLL, H etc. are mentioned. The content of the xylene resin is 0.1 to the total amount of the epoxy resin composition.
20% by weight is suitable, more preferably 2 to 15% by weight
Is. If the content is less than 0.1% by weight, the compounding effect will not be exhibited, and if it exceeds 20% by weight, defects such as embossing of the xylene resin as a non-reactive plasticizer will appear.

〔The invention's effect〕

The liquid epoxy resin composition of the present invention has both excellent heat cycle resistance and moisture resistance (particularly pressure cooker resistance), and is suitable as a casting material, especially for electric / electronic parts. The reliability can be increased.
That is, in comparison with the conventional liquid epoxy resin composition, the heat cycle resistance is improved by 3 to 4 times or more, and the pressure cooker resistance is considerably improved.

〔Example〕

 The present invention will be specifically described below with reference to examples.

In the two-pack type epoxy resin composition as shown in Table-1, the filler content was all 60%, and fused silica (average particle size: about 20 μm) was used. The effect condition is 120 ° C. for 5 hours.

The characteristic results are shown in the lower column of Table-1.

[Test Method] (1) Pressure Cooker Test Condition: A test piece (50 mmφ × 3 mm) was treated in a steam bath at 125 ° C. and 2.3 atm, and the appearance and weight change were observed.

(2) Heat cycle property Test piece: C washer (SUS, diameter 20 mm) embedded cured product (50 mmφ × 10 mm) Condition treatment: −50 ° C./150° C. angle 1 hour. The appearance (whether or not cracks were generated) was observed (n = 5).

Comparative Example 3 with the formulation shown in Table 2 in the same manner as in Example
~ 5 were carried out and the results are shown together.

As shown in Example 1, when the diaminodiphenylmethane-based eutectic mixture was used, excellent characteristics were obtained in which the pressure cooker property and the heat cycle property were well balanced, but as shown in Comparative Examples 1 to 5. When an acid anhydride is used as the material, the pressure cooker property is good, but the heat cycle property is poor and the balance cannot be achieved. Even when the diaminodiphenylmethane-based eutectic mixture is used, the same pressure is applied when both the silicon compound and the xylene resin (Comparative Example 1) or either one (Comparative Examples 3 and 4) is omitted. It is not possible to obtain a material that is well-balanced in both cooker property and heat cycle property. Furthermore, even if a liquid aromatic amine is used (Comparative Example 5)
It is not possible to obtain excellent balance as in the case of using a diaminodiphenylmethane eutectic mixture.

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Claims (1)

[Claims] 1. A liquid epoxy resin composition containing an inorganic filler, wherein the composition comprises (a) a xylene resin and (b).
A liquid epoxy resin composition comprising a eutectic mixture of a diaminodiphenylmethane amine and another aromatic amine and (c) a silicone resin represented by the following general formula (1). (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ ,
Are methyl groups or phenyl groups, of which 2 to 6 are methyl groups and 2 to 6 are phenyl groups. )