JP3450260B2 - Epoxy resin composition and coil casting - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to heat resistance, moldability,
The present invention relates to an epoxy resin composition having excellent crack resistance and a coil casting product obtained by casting the epoxy resin composition.

[0002]

2. Description of the Related Art Conventionally, electric and electronic parts such as coils have been cast or sealed with an epoxy resin or impregnated and coated with an epoxy resin to be cured in order to protect them from an external atmosphere and mechanical shock. Has been done.

In recent years, not only the characteristics related to coil castings, that is, reliability such as heat resistance, moldability, and crack resistance, but also improvement in productivity such as cost reduction are demanded. Things have come to be demanded.

[0004]

However, increasing the amount or changing the type of the curing accelerator in the composition not only leads to a decrease in reliability and the pot life of the resin, but also the current molding, It may be necessary to make a drastic change in the casting method, and it has been difficult to quickly cure only the epoxy resin composition while maximizing the current process.

The object of the present invention was made in view of the above circumstances, and provides an epoxy resin composition and a coil casting product which are excellent in heat resistance and moldability and have a rapid curing property suitable for coil casting and the like. It is the one we are trying to provide.

[0006]

As a result of intensive studies aimed at achieving the above object, the present inventor has found that the above object can be achieved by using a specific acid anhydride curing agent, and It has been completed.

That is, the present invention comprises (A) an epoxy resin, (B) isomers (a) 4-methylhexahydrophthalic anhydride and (b) 3-methylhexahydrophthalic anhydride as main components. In methylhexahydrophthalic anhydride,
(C) 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and (d) 3-methyl-Δ ² -tetrahydrophthalic anhydride
An acid anhydride curing agent containing a mixture of 0.1% by weight or more and less than 5% by weight, (C) a curing accelerator and (D) an inorganic filler as essential components, and (A) an epoxy resin and (D) an inorganic filler. And a mixture of an epoxy resin compounding component consisting of (B), an acid anhydride curing agent of (B) and a curing agent compounding component of (C) a curing accelerator .
It is an epoxy resin composition characterized by being applied to casting of products (excluding products) . A coil casting product is obtained by casting the epoxy resin composition. Na
Here, the optical product refers to JP-A-1-132621.
The optical materials and optical products described in the publication.

The present invention will be described in detail below.

As the epoxy resin (A) used in the present invention, as long as it is a compound having two or more epoxy groups in one molecule, general-purpose resins are widely used without being limited by the molecular structure, molecular weight and the like. be able to. For example, an epoxy novolac type, a biphenyl type aromatic type, an alicyclic type cyclohexane derivative or the like, and a bisphenol A type epoxy resin represented by the following general formula can be given.

[0010]

[Chemical 1] (However, in the formula, n represents an integer of 0 or more.) These may be used alone or in combination of two or more.

The specific curing agent of the component (B) used in the present invention is 4-methylhexahydrophthalic anhydride (a) represented by the following formula 2 which is an isomer of methylhexahydrophthalic anhydride as a main component. When

[Chemical 2] In a mixture of (b) 3-methylhexahydrophthalic anhydride represented by the following formula 3,

[Chemical 3] (C) 3-methyl-Δ ¹ -tetrahydrophthalic anhydride represented by the following formula 4

[Chemical 4] (D) 3-Methyl-Δ ² -tetrahydrophthalic anhydride represented by the following formula 5

[Chemical 5] Further, the compounding ratio of them is such that the total amount of the (c) component and the (d) component is 0.1% by weight or more in the main component mixture of the (a) component and the (b) component. The content is less than 5% by weight, preferably 0.1% by weight or more and less than 3% by weight. If this ratio is less than 0.1% by weight, the effect on the rapid curing property is small, and if it is 5% by weight or more, the glass transition point is lowered and the heat resistance is lowered, which is not preferable.

The (C) curing accelerator used in the present invention may be any one that accelerates the reaction between the epoxy resins of (A) or between the epoxy resin of (A) and the curing agent of (B).
It can be anything. Specifically, for example, 2
-Imidazoles such as ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo [5,4,0] undecene -7, tertiary amines such as benzyldimethylamine, triethylphosphine, diphenylphosphine, triphenylphosphine and the like can be mentioned, and these can be used alone or in admixture of two or more.

As the inorganic filler (D) used in the present invention, generally used ones are widely used. Specific examples include silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, bengal, glass fiber, carbon fiber, and the like, and silica powder and alumina are particularly preferably used. The compounding ratio of the inorganic filler is 25 with respect to the total resin composition.
It is preferable to mix such that the content is from ˜95% by weight.
If the proportion is less than 25% by weight, the resin composition has a high hygroscopicity and is inferior in moisture resistance.

The epoxy resin composition of the present invention contains the above-mentioned epoxy resin, acid anhydride curing agent, curing accelerator and inorganic filler as essential components, but within the range not deviating from the object of the present invention, If necessary, for example, a reactive diluent such as an alicyclic epoxy and a silane coupling agent, various anti-sedimentation agents, a coloring agent such as carbon black, and the like can be appropriately added and blended.

When the epoxy resin composition of the present invention is prepared, an epoxy resin compounding component is prepared by compounding the epoxy resin with an inorganic filler, and if necessary, a reactive diluent, a colorant and an antisettling agent. A casting material can be obtained by heating and kneading the acid anhydride curing agent and the curing agent compounding component consisting of the curing accelerator.

The above-mentioned curing agent compounding component comprising (B) acid anhydride curing agent and (C) curing accelerator is the above-mentioned (A).
It is blended in a proportion of 3 to 30% by weight with respect to the main component epoxy resin blending component comprising the epoxy resin and the inorganic filler (D).

When the casting material thus obtained is applied to sealing, coating, insulation, etc. of electric parts or electronic parts such as coil casting, excellent properties and reliability can be imparted. As a general method of casting, there is vacuum casting, but a specific epoxy resin, an inorganic filler, and other components are blended, and the resin component is sufficiently evenly heated and mixed by a mixer, etc., a curing agent, and a curing agent. Two resin components, which are a resin component that has been mixed with an accelerator and other components and heated and mixed sufficiently evenly with a mixer, etc., are pre-mixed, and after sealing by a casting method, cured by heating and coil casting. The thing is obtained.

[0018]

The epoxy resin composition of the present invention is excellent in heat resistance, moldability and the like by adding a specific acid anhydride curing agent to the base epoxy resin, and is suitable for coil casting and the like. It is possible to provide an epoxy resin composition that has heat resistance and moldability, is excellent in rapid curing property, and can improve productivity.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be specifically described with reference to Examples. The invention is not limited by these examples.

Example 1 100 parts by weight of an epoxy resin (epoxy equivalent 190), 180 parts by weight of fused silica, 0.1 part by weight of an acrylic defoaming agent, and 0.3 part by weight of a silane coupling agent were charged into a mixer, The mixture was heated and mixed at 60 ° C. to obtain an epoxy resin compounding component. Separately, 67 parts by weight of 4-methylhexahydrophthalic anhydride and 17 parts of 3-methylhexahydrophthalic anhydride
5 parts by weight of 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and 3-methyl-Δ ² -tetrahydrophthalic anhydride
0.1 parts by weight of a 0:50 mixture, and 1-benzyl-
0.4 parts by weight of 2-methylimidazole was charged into a mixer and mixed by heating at 60 ° C. to prepare a curing agent blending component. Mixing the above epoxy resin blending component and curing agent blending component,
The epoxy resin composition of Example 1 was obtained.

Examples 2 to 3 The epoxy resin compounding component and the curing agent compounding component having the compositions shown in Table 1 were heated and mixed at 60 ° C., respectively, and then the epoxy resin compounding component and the curing agent compounding component were mixed to obtain the examples. A few epoxy resin compositions were obtained.

Comparative Examples 1 to 3 The epoxy resin compounding components and the curing agent compounding components having the compositions shown in Table 2 were heated and mixed at 60 ° C. in the same manner as in the examples, and then the epoxy resin compounding component and the curing agent compounding component were mixed. Were mixed to obtain the epoxy resin compositions of Comparative Examples 1 to 3.

The epoxy resin compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were cast in a test piece forming mold under vacuum at 60 ° C. for 3 hours at 100 ° C. and then at 130 ° C. It was post-cured at ℃ for 3 hours. Various tests were conducted on these epoxy resin compositions, and the results are shown in Table 3. The remarkable effects of the present invention could be confirmed.

[0024]

[Table 1] *: The standard amount of 1-benzyl-2-methylimidazole is 0.6 part by weight, but the amount of 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and 3-methyl-Δ ² -tetrahydrophthalic anhydride is When the mixture was 0.1 parts by weight or less, it increased (0.8 parts by weight), when it was 5.0 parts by weight, it decreased (0.4 parts by weight), and the gel time was adjusted to be close to 53 minutes.

[0025]

[Table 2] *: The standard amount of 1-benzyl-2-methylimidazole is 0.6 part by weight, but the amount of 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and 3-methyl-Δ ² -tetrahydrophthalic anhydride is When the mixture was 0.1 parts by weight or less, it increased (0.8 parts by weight), when it was 5.0 parts by weight, it decreased (0.4 parts by weight), and the gel time was adjusted to be close to 53 minutes.

[0026]

[Table 3] * 1: By TMA method * 2: Defects such as voids in the appearance of the cured product were visually observed.

[0027]

As is clear from the above description and the results in Table 3, 0.1% by weight of the mixture of 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and 3-methyl-Δ ² -tetrahydrophthalic anhydride was used. If it is less than%, there is no rapid curing property (Comparative Example 1), and if it exceeds 5.0% by weight, the glass transition point is lowered (Comparative Examples 2 and 3). Therefore, the epoxy resin composition of the present invention is an epoxy resin composition having excellent heat resistance and moldability and having a rapid curing property, and is suitable for coil casting, sealing and the like.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01F 5/06 H01F 5/06 27/32 27/32 // B29K 63:00 B29K 63:00 B29L 31:34 B29L 31:34 (56) References JP-A-1-132621 (JP, A) JP-A-4-76020 (JP, A) JP-A-7-309927 (JP, A) JP-A-3-243617 (JP, A) (58) Survey Fields (Int.Cl. ⁷ , DB name) C08G 59/00-59/72 B29C 39/10 C08J 5/00-5/24 C08L 63/00-63/10 H01F 5/06 H01F 27/32

Claims (2)

(57) [Claims] 1. An epoxy resin (A), an isomer (B) of 4-methylhexahydrophthalic anhydride (b) and an (B) isomer.
(C) 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and (d) 3-methyl-Δ ² -tetrahydrophthalic anhydride in methylhexahydrophthalic anhydride containing 3-methylhexahydrophthalic anhydride as a main component. An acid anhydride curing agent containing 0.1% by weight or more and less than 5% by weight of a mixture of acids, (C) a curing accelerator, and (D) an inorganic filler as essential components, and (A) an epoxy resin and (D) an inorganic substance. an epoxy resin blend component consisting of a filler, an acid anhydride curing agent (B) and (C) Ri greens by mixing the curing agent blend component comprising a curing accelerator, electric and electronic parts (except, optical For
The epoxy resin composition for casting, which is applied to the casting (excluding products) . 2. A coil casting product obtained by casting the epoxy resin composition according to claim 1.