JP2623823B2 - Epoxy resin composition - Google Patents

Description

The present invention relates to an epoxy resin composition, and more particularly, to an epoxy resin composition suitable as an insulating material for electric equipment.

[Conventional technology]

Conventionally, it is known that when an acid anhydride and an amine compound are used as a curing agent in an epoxy resin, the cured product is excellent in electrical properties, mechanical properties, and crack resistance. In addition, when a filler is added to the epoxy resin composition, electrical properties, mechanical properties and crack resistance can be further improved, so various fillers are used depending on the application.

In recent years, in order to reduce the size of electric devices, complicate the shape, and increase the operating temperature, there has been a further demand for improved crack resistance of epoxy resin compositions used as insulating materials.

In order to improve the crack resistance of the epoxy resin, a method of using a large amount of filler to increase the filling and reduce the thermal expansion has been used, and a filler with a wide particle size distribution is used in this case. Have been. However, when there are many fine particles, the particle size increases significantly and workability is inferior, and when there are many coarse particles, the filler sediments during curing, and as a result, the filler content at the top and bottom of the casting decreases. There is a problem that a difference is generated and a crack is generated in a portion where the content of the filler is small due to the heat cycle.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, to increase the amount of the filler without increasing the viscosity of the resin composition, and to reduce the thermal expansion of the filler during curing with less sedimentation. An epoxy resin composition of the present invention.

[Means for solving the problem]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found that it can be achieved by using two types of fillers having different particle diameters in combination at a specific mixing ratio as a filler. Reached.

That is, the present invention provides an epoxy resin composition containing an epoxy resin having at least one epoxy group in one molecule, a filler, and a curing agent, wherein the filler has (A) an average particle size Is 12-18 μm and the particle size distribution is 20
a filler having a cumulative weight% of 80 μm or less and a cumulative weight% of 6 μm or less of 10% or less, and (B) an average particle size of 3 to
The cumulative weight% of 5 μm having a particle size distribution of 6 μm or less is 80%.
% And a filler with a cumulative weight% of 2 μm or less of 20% or less, and a blending weight ratio of the filler (A)
/ (B) is 75/25 to 25/75.

The epoxy resin used in the present invention contains at least one epoxy group in one molecule. For example, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, polyhydric alcohol Glycidyl esters and the like can be used. These resins are not particularly limited, but are preferably liquid at room temperature.
(Trade name, manufactured by Shell Chemical Co., Ltd.), GY-260 (trade name, manufactured by Ciba Geigy), DER-331 (trade name, manufactured by Dow Chemical Company), and the like can be used. These can be used in combination.

The filler used in the present invention has an average particle size of 12 to 18 μm
A filler (A) having a particle size distribution of 80% or more of a cumulative weight% of 20 μm or less and a 10% or less of a cumulative weight% of 6 μm or less, and a filler having an average particle size of 3 to 5 μm and a particle size distribution of
A filler (B) having a cumulative weight% of 80 μm or less and a filler (B) having a cumulative weight% of 2 μm or less of 20% or less is mixed with the filler (A) / (B) = 75/25 to 25/75. It is used by mixing so that

As these fillers, for example, crystalline silica, fused silica, hydrated alumina, alumina oxide, talc, calcium carbonate, mica, glass powder, magnesium hydroxide, clay and the like are used, and commercially available products such as C-315H, C- 303H (hydrated alumina, trade name, manufactured by Sumitomo Chemical Co., Ltd.) or the like can be used.

The reason why the average particle size and the like of the filler (A) is limited to the above range is that it is preferable in terms of the sedimentation property of the filler and the viscosity of the obtained composition.

The reason why the average particle size and the like of the filler (B) is limited to the above range is that it is preferable in view of the viscosity of the obtained composition and the sedimentation of the filler.

Further, when the above-mentioned weight ratio of the filler (A) exceeds 75, the sedimentation at the time of curing is large, and uniform physical properties cannot be obtained as a cast product. If it exceeds 7, the viscosity increases, the thixotropic property increases, and the filling of the filler cannot be increased.

The total amount of the fillers (A) and (B) is preferably in the range of 50 to 300 parts by weight based on 100 parts by weight of the epoxy resin. By using such a filler, the amount of the filler in the composition can be increased, and since the sedimentation is small, uniform physical properties can be obtained in any part of the cast material.

An acid anhydride or an amine compound is used as a curing agent, and examples of the acid anhydride include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylendmethylene phthalic anhydride, dodecenyl phthalic anhydride and the like. These are not particularly limited, but are preferably liquid at room temperature, and commercially available products such as HN-2200 (trade name, manufactured by Hitachi Chemical Co., Ltd.) and QH-200 (trade name, manufactured by Zeon Corporation) can be used. These can be used in combination. The amount of the acid anhydride is preferably 50 to 150 parts by weight based on 100 parts by weight of the epoxy resin.

Examples of the amine compound include an aromatic polyamine and a modified product thereof, and an aliphatic polyamine and a modified product thereof. Examples thereof include an adduct of diaminodiphenylmethane and an epoxy resin. ),
Ancamine 2007 (manufactured by Anchor Chemical) is used. These can be used in combination. The amount of the amino compound is 5 to 5 parts by weight per 100 parts by weight of the epoxy resin.
0 parts by weight is preferred.

In the epoxy resin composition of the present invention, as a curing accelerator for the acid anhydride curing agent, for example, 2-ethyl-4-methylimidazole, 1-cyanoethyl-4-methylimidazole, 1-benzyl-2-ethylimidazole and the like Tertiary amines such as imidazole and its derivatives, trisdimethylaminophenol and benzenemethylamine can also be used. These commercial products are 2E4MZ
(Trade name of Shikoku Chemicals), BDMA (trade name of Kao Corporation) and the like. The compounding amount is 0.1 to 5.
0 parts by weight is preferred.

The epoxy resin composition of the present invention may further contain, if necessary, a flame retardant such as red phosphorus, hexabromobenzene, dibromophenyl glycidyl ether, dibromocresyl glycidyl ether, antimony trioxide;
Coloring agents such as iron, carbon, and titanium white, silane-based coupling agents, silicone defoamers, and diluents such as monoglycidyl ether and diglycidyl ether can be added.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

The particle size distribution, viscosity, linear expansion coefficient, crack generation cycle number, and sedimentation of the filler in the examples were measured by the following methods.

(1) Particle Size Distribution of Filler: Using SEDIGRAPH 5000ET (manufactured by Shimadzu Corporation) with a starting particle diameter of 50 μm, about 8% of filler in an aqueous solution of 0.1% by weight of sodium hexametaphosphate.
The solution was added at a concentration of% by weight, and ultrasonic cleaning was performed for 20 minutes as a preliminary dispersion, and the measurement was performed.

(2) Viscosity: Measured in a constant temperature bath at 25 ° C. using a BH-type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd.).

(3) Coefficient of linear expansion: 100 g of the epoxy resin composition is cured at 80 ° C. for 3 hours and further at 100 ° C. for 3 hours, and is 5 mm × 5 mm × 2 mm
Was cut out and measured with a thermophysical tester (manufactured by PerkinElmer).

(4) Number of crack generation cycles: A 1 / 2-inch iron spring washer was set on a 60 mm-diameter metal petri dish, 30 g of an epoxy resin composition was injected, and cured under the same conditions as (3) to obtain a test piece. Remove the Petri dish after curing and JI
A heat cycle test was performed according to the heat cycle conditions of SC-2105 (shown in Table 5) to confirm the state of crack generation. The number of test pieces was three, and the number of test pieces was represented by the total number of cycles in which the last one had cracks.

(5) Sedimentability: 130 m in a polyethylene test tube with a diameter of 18 mm
After the epoxy resin composition was injected to a height of m, and cured under the same conditions as in (3), the burning residue at the upper and lower ends of the cured product at 1 cm each was measured to determine the difference between the upper and lower portions. The greater the difference, the greater the settling during curing.

Examples 1 to 6 C-315H and C-303H (trade name, manufactured by Sumitomo Chemical Co., hydrated alumina) having the characteristics shown in Table 1, prototype A and prototype B (silica, manufactured by Tatsumori Co.) An epoxy resin composition was prepared by using the compound and the amount (unit: parts by weight) shown in Table 2 as a filler, and the properties thereof were evaluated. The results are shown in Table 2. As shown in Table 2, the viscosity was 1000 P or less and the workability was excellent and the sedimentation was small even when the filler was highly filled.

Comparative Examples 1 to 12 In addition to the fillers used in the examples, H-32, H-42 (trade name, manufactured by Showa Denko KK, hydrated alumina), C-325, CM-45 having the properties shown in Table 3 , C-308N, C-301 (trade name, manufactured by Sumitomo Chemical Co., hydrated alumina) and CRT-D (trade name, manufactured by Tatsumori Co., silica), the blends and blend amounts (units) shown in Table 4 (Parts by weight) was used to prepare an epoxy resin composition, and its characteristics were evaluated. The results are shown in Table 4.

In Comparative Examples 3, 11, and 12, hydrated alumina H-32 and silica CRT-D, which are generally used for filling epoxy resin, were used alone, but all had high viscosity of the composition and were inferior in workability. Was.

In Comparative Examples 1, 2, 9 and 10, hydrated alumina C-31
5H, C-303H, silica prototype A and prototype B were each used alone. In Comparative Examples 1 and 9, the viscosity of the composition was low, but the sedimentation was as large as 7 to 9%. Comparative Example 2
In Nos. 10 and 10, the viscosity was significantly increased and workability was poor.

In Comparative Examples 4, 5 and 6, hydrated alumina C-325, C
When hydrated alumina C-303H was used in combination with M-45 and C-308N, a composition having low viscosity and small sedimentation was not obtained.

In Comparative Examples 7 and 8, hydrated alumina C-315H was used in combination with hydrated alumina C-301 and H-42, respectively, but a composition having low viscosity and small sedimentation was not obtained.

[Effects of the Invention] The epoxy resin composition of the present invention can be highly filled with a filler without increasing the viscosity, so that the epoxy resin composition has excellent low thermal expansion, crack resistance, and thermal conductivity, and also has excellent filling during curing. Since the agent has a small sedimentation property and is stable in quality, it has excellent tracking resistance, arc resistance, and dielectric properties.

The epoxy resin composition of the present invention can be widely used for various transformers which simultaneously perform impregnation and casting, and for impregnation and casting of electric and electronic parts.

Claims (1)

(57) [Claims] 1. An epoxy resin composition comprising an epoxy resin having at least one epoxy group in one molecule, a filler, and a curing agent, wherein the filler is (A)
80% or more of the cumulative weight% having an average particle size of 12 to 18 μm and a particle size distribution of 20 μm or less, and 10% of the cumulative weight% of 6 μm or less.
And (B) a cumulative weight% of 80% or more having an average particle size of 3 to 5 μm and a particle size distribution of 6 μm or less;
It is a mixture with a filler whose cumulative weight% of μm or less is 20% or less, and the compounding weight ratio (A) / (B) of the filler is
An epoxy resin composition having a ratio of 75/25 to 25/75.