JP2001048958A - Epoxy resin composition and coil cast material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition excellent in heat resistance and molding property, and having a rapid curing property suitable for a coil casting, and a coil cast material. SOLUTION: This epoxy resin composition consists of (A) an epoxy resin, (B) an acid anhydride curing agent of methylhexahydrophthalic anhydride consisting of (a) 4-methyl substituted and (b) 3-methyl substituted isomers as main components, and containing (c) 3-methyl-Δ1-tetrahydrophthalic acid anhydride and (d) 3-methyl-Δ2-tetrahydrophthalic acid anhydride in >=1 wt.% and <5 wt.% their total amount, (C) a curing accelerating agent and (D) and inorganic filler as essential components, and is obtained by mixing an epoxy resin formulated component consisting of (A) the epoxy resin and (D) the inorganic filler with a curing agent formulated component consisting of (B) the acid anhydride curing agent and (C) a curing accelerating agent. A coil cast material is produced by casting the above composition.

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 obtained by casting the epoxy resin composition.

[0002]

2. Description of the Related Art Conventionally, electric and electronic components such as coils have been cast and sealed with epoxy resin, or impregnated with epoxy resin, applied and cured in order to protect against external atmosphere and mechanical shock. Has been done.

[0003] In recent years, in order to improve the properties of coil cast products, that is, not only reliability such as heat resistance, moldability, and crack resistance, but also to improve productivity such as cost reduction, a rapidly curable epoxy resin composition has been required. Things have come to be required.

[0004]

However, increasing the amount or changing the type of the curing accelerator in the composition not only lowers the reliability or significantly lowers the pot life of the resin, but also reduces the current molding and curing properties. In some cases, a significant change in the casting method was required, and it was difficult to quickly cure only the epoxy resin composition while maintaining the current process to the maximum.

An object of the present invention has been made in view of the above circumstances, and is intended to provide an epoxy resin composition having excellent heat resistance and moldability, and having a rapid curing property suitable for coil casting and the like. It is something to offer.

[0006]

Means for Solving the Problems As a result of diligent research 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. It is completed.

That is, the present invention provides (A) an epoxy resin,
In (B) isomers (a) methylhexahydrophthalic anhydride containing 4-methylhexahydrophthalic anhydride and (b) 3-methylhexahydrophthalic anhydride as main components,
An acid anhydride curing agent containing a total amount of (c) 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and (d) 3-methyl-Δ ² -tetrahydrophthalic anhydride of 0.1% by weight or more and less than 5% by weight. And (C) a curing accelerator and (D) an inorganic filler as essential components; (A) an epoxy resin compounding component comprising an epoxy resin and (D) an inorganic filler; and (B) an acid anhydride curing agent. (C) An epoxy resin composition characterized by mixing with a curing agent compounding component comprising a curing accelerator. Further, a coil casting is obtained by casting the epoxy resin composition.

Hereinafter, the present invention will be described in detail.

As the epoxy resin (A) used in the present invention, general-purpose resins are widely used without being limited by molecular structure, molecular weight, etc., as long as they are compounds having two or more epoxy groups in one molecule. be able to. For example, aromatic resins such as epoxy novolak type and biphenyl type, alicyclic types such as cyclohexane derivative, and bisphenol A type epoxy resin represented by the following general formula can be used.

[0010]

Embedded image (In the formula, n represents an integer of 0 or more.) These can be used alone or in combination of two or more.

As the specific curing agent of the component (B) used in the present invention, methyl hexahydrophthalic anhydride is a main component and its isomer, (a) 4-methylhexahydrophthalic anhydride represented by the following formula (2): When

Embedded image In a mixture of (b) 3-methylhexahydrophthalic anhydride shown in the following formula 3,

Embedded image (C) 3-methyl-Δ ¹ -tetrahydrophthalic anhydride represented by the following formula 4

Embedded image (D) 3-methyl-Δ ² -tetrahydrophthalic anhydride represented by the following formula 5

Embedded image The compounding ratio thereof is such that the total amount of the component (c) and the component (d) is 0.1% by weight or more in the main component mixture of the component (a) and the component (b). It is blended so as to contain less than 5% by weight, preferably from 0.1% by weight to less than 3% by weight. When the proportion is less than 0.1% by weight, the effect on the rapid curing property is small, and when the proportion 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 which promotes the reaction between the epoxy resins (A) or the epoxy resin (A) and the curing agent (B).
Anything may be used. Specifically, for example, 2
Imidazoles such as -ethyl-4-methylimidazole, 2-phenylimidazole and 2-phenyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo [5,4,0] undecene -7, tertiary amines such as benzyldimethylamine, triethylphosphine, diphenylphosphine, triphenylphosphine, etc., and these can be used alone or in combination of two or more.

As the inorganic filler (D) used in the present invention, those generally used are widely used. Specifically, for example, silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, bengal, glass fiber, carbon fiber and the like can be mentioned, and silica powder and alumina are particularly preferably used. The mixing ratio of the inorganic filler is 25 to the entire resin composition.
It is preferable to mix so as to contain the content of about 95% by weight.
If the proportion is less than 25% by weight, the resin composition has high hygroscopicity and is inferior in moisture resistance, and if it exceeds 95% by weight, the fluidity is extremely deteriorated, and the workability in casting is inferior.

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. If necessary, for example, a reactive diluent such as an alicyclic epoxy and a silane coupling agent, or various anti-settling agents and a coloring agent such as carbon black can be appropriately added and blended.

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

The curing agent compounding component comprising the above-mentioned (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 composed of the epoxy resin and the inorganic filler (D).

The cast material thus obtained can provide excellent properties and reliability when applied to sealing, coating, insulation, etc. of electric parts or electronic parts such as coil casting. As a general casting method, there is vacuum casting, but a specific epoxy resin, an inorganic filler, and other components are blended, and the mixture is heated and mixed sufficiently uniformly with a mixer or the like, a curing agent, and a curing agent. Accelerator and other components are blended, and the two resin components are mixed in advance with the resin component heated and mixed sufficiently uniformly by a mixer or the like. Things are obtained.

[0018]

The epoxy resin composition of the present invention has excellent reliability such as heat resistance and moldability by blending a specific acid anhydride curing agent with the base epoxy resin, and is suitable for coil casting and the like. It is possible to provide an epoxy resin composition having heat resistance, moldability, excellent curability, and improved productivity.

[0019]

Next, the present invention will be specifically described with reference to examples. The present 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 parts by weight of an acrylic defoamer, and 0.3 parts 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, 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 mixture of 0:50 and 1-benzyl-
0.4 part by weight of 2-methylimidazole was charged into a mixer, and heated and mixed at 60 ° C. to obtain a hardener compounding component. Mix the above epoxy resin compounding component and curing agent compounding component,
The epoxy resin composition of Example 1 was obtained.

Examples 2-3 The epoxy resin compounding component and the curing agent compounding component having the compositions shown in Table 1 were mixed by heating at 60 ° C., and then the epoxy resin compounding component and the curing agent compounding component were mixed. Two or three epoxy resin compositions were obtained.

Comparative Examples 1 to 3 Epoxy resin components and curing agent 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 epoxy resin components and curing agent components. Were mixed to obtain epoxy resin compositions of Comparative Examples 1 to 3.

The epoxy resin compositions prepared according to Examples 1 to 3 and Comparative Examples 1 to 3 were cast under vacuum at 60 ° C. into a mold for preparing test pieces, and at 100 ° C. for 3 hours. Post-curing was carried out at 3 ° C. 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 parts by weight, and the amount of 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and 3-methyl-Δ ² -tetrahydrophthalic anhydride When the mixture was 0.1 part by weight or less, the mixture increased (0.8 parts by weight), and when the mixture was 5.0 parts by weight, 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 parts by weight, and the amount of 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and 3-methyl-Δ ² -tetrahydrophthalic anhydride When the mixture was 0.1 part by weight or less, the mixture increased (0.8 parts by weight), and when the mixture was 5.0 parts by weight, 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 apparent from the above description and the results in Table 3, 0.1% by weight of a mixture of 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and 3-methyl-Δ ² -tetrahydrophthalic anhydride was used. %, There is no quick-curing property (Comparative Example 1), and if it exceeds 5.0% by weight, the glass transition point decreases (Comparative Examples 2, 3). Therefore, the epoxy resin composition of the present invention is an epoxy resin composition having excellent heat resistance and moldability and having rapid curing properties, and is suitable for coil casting, sealing, and the like.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01F 5/06 H01F 5/06 R 27/32 27/32 A // B29K 63:00 B29L 31:34 F term (reference ) 4F071 AA42 AC09 AC12 AC15 AE02 AE03 AE17 AH12 BB01 BC02 4F204 AA39 AB03 AB11 AG08 AH33 EA03 EB01 EF02 EF27 EK17 EK24 4J002 CD02W CD05W CD06W DA018 DE118 DE128 DE138 DE148 DE238 DJ018 EU0 014 014 AD08 AD14 AD15 AF06 AF26 AF27 AF29 DA05 DB15 DB17 DC05 DC13 DC40 DC41 DC46 DD07 FA02 FA03 FA05 JA05 5E044 AA01 AB01 AB07 AC04 AD00

Claims (2)

[Claims] 1. An epoxy resin (A), (B) isomer (a) 4-methylhexahydrophthalic anhydride and (b)
In methylhexahydrophthalic anhydride containing 3-methylhexahydrophthalic anhydride as a main component, (c) 3-methyl-Δ ¹ -tetrahydrophthalic anhydride and (d) 3-methyl-Δ ² -tetrahydrophthalic anhydride Acid anhydride curing agent containing a total amount of acid 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;
An epoxy resin compounding component comprising (A) an epoxy resin and (D) an inorganic filler, and a curing agent compounding component comprising (B) an acid anhydride curing agent and (C) a curing accelerator. An epoxy resin composition, characterized in that: 2. A coil casting obtained by casting the epoxy resin composition according to claim 1.