JP5642917B2 - Epoxy resin composition for impregnating mold coil and mold coil apparatus - Google Patents

Description

  The present invention relates to an epoxy resin composition for impregnating a mold coil and a mold coil device, and in particular, is cast by an epoxy resin composition suitable for insulation of an ignition coil that requires a high withstand voltage and the epoxy resin composition. The present invention relates to a mold coil device.

Many electrical equipment parts are cast-sealed with a casting resin composition for the purpose of protecting, insulating, and the like of the component parts. For the impregnation casting of an ignition coil, an epoxy resin composition excellent in insulation, mechanical properties, crack resistance and long-term reliability is often used. In recent years, the insulation distance has been reduced due to the complexity of built-in parts due to multifunctionalization and miniaturization, etc., and the resin composition for casting has been increasingly demanded for dielectric breakdown, and a resin composition with long-term reliability has been demanded. It has been. In such an epoxy resin composition, as a method of imparting insulation reliability, reducing the impurity content of the resin or adding a specific functional resin powder is performed (for example, Patent Documents 1 to 5). 2).
JP-A-2005-187609 JP 2006-169912 A

  However, such a method cannot prevent a decrease in the mechanical strength of the cured product, and even if it can improve the initial breakdown voltage, it can prevent a decrease in the breakdown voltage in the energized state. Is not sufficient, and it is difficult to impregnate resin into a pen-type ignition coil or the like, which has a particularly strong demand for high insulation reliability.

  Therefore, the present invention has been made to solve such a conventional problem, and is excellent in mechanical strength, can maintain a high dielectric breakdown voltage not only in an initial state but also in an energized state, and a coil. It is an object of the present invention to provide an epoxy resin composition excellent in impregnating property and a molded coil device using the epoxy resin composition.

The epoxy resin composition for impregnating a mold coil of the present invention is a resin composition suitable for casting and having excellent insulation reliability by using a predetermined amount of specific silica powder. That is, the epoxy resin composition of the present invention comprises (A) an epoxy resin, (B) silica particles, (F) a main component containing titanium oxide fine particles as essential components, and (C) an acid anhydride. , (D) a curing agent component containing a curing accelerator as an essential component, and (B) silica particles having an average particle diameter of 10 to 30 μm and an average in combination with particles having a particle diameter 0.01～1.5Myuemu, and silica particles having an average particle size of 10 to 30 [mu] m, 30 to 85 wt% observed containing the epoxy resin composition, wherein the (F) titanium oxide particles The fine particles having an average particle diameter of 0.05 to 0.3 μm are contained in an amount of 0.05 to 5.0 parts by mass with respect to 100 parts by mass of the (B) silica particles .

  The molded coil device of the present invention is characterized in that the coil is impregnated and cured with the epoxy resin composition for impregnating a molded coil of the present invention.

  According to the epoxy resin composition for impregnating a molded coil of the present invention, a cured product excellent in insulation reliability is achieved by improving the mechanical strength of the cured product and the dielectric breakdown voltage in an energized state. The molded coil can be manufactured at low cost.

  In addition, according to the molded coil device of the present invention, a molded coil excellent in mechanical strength and insulation reliability can be obtained by impregnation and production using the resin composition of the present invention, and a product with high operational reliability. Can be provided.

  Hereinafter, the present invention will be described in detail.

  As (A) epoxy resin used for this invention, what is generally used is not restrict | limited to molecular weight, molecular structure, etc., if it has 2 or more epoxy groups in 1 molecule. Examples thereof include aromatic epoxy resins such as bisphenol type, novolak type and biphenyl type, alicyclic epoxy resins obtained by epoxidation of glycidyl ether of polycarboxylic acid, cyclohexane derivatives, etc. Can be used alone or in admixture of two or more.

  In addition, a liquid monoepoxy resin or the like can be used as a combination component if necessary, and a halogen-based epoxy resin can also be used when imparting flame retardancy. it can.

  As (B) silica particles used in the present invention, silica particles having an average particle size of 10 to 30 μm are contained in an amount of 30 to 85% by mass, and preferably 40 to 70% by mass in the entire epoxy resin composition. It is. As a result, it is possible to prevent a decrease in dielectric breakdown voltage in the energized state. This is because if the tree generated in the energized state has an average particle diameter of 10 to 30 μm, the formation path distance becomes longer than when silica particles having a smaller average particle diameter are used, and the tree path This is because it becomes difficult to grow.

  The silica particles may be silica particles that are usually blended into the resin composition for impregnation. For example, crystalline silica, fused silica, fused spherical silica, and crushed silica can be used without distinction, but the resin composition From the viewpoints of viscosity, resistance to dielectric breakdown, etc., fused spherical silica is preferred. In the case of crushed silica, electric field concentration is likely to occur due to an acute angle, but in the case of spherical silica, such electric field concentration is unlikely to occur, and dielectric breakdown is less likely to occur. More specifically, for example, MSR-25, MSR-2212 (above, made by Tatsumori Co., Ltd., trade name), FB74, FB940, FB942 (above, made by Denki Kagaku Kogyo Co., Ltd., trade name) and the like can be mentioned. . These can be used alone or in admixture of two or more.

If silica particles having a relatively large particle size are used as described above, the strength of the cured product may be reduced and the silica may be precipitated in the resin composition. To prevent this, the average particle size is 0.01 to 1. .5μm of fine silica it is preferable to use 併. The finely divided silica such as this, for example, crystallites 5X, Fuselex X (or, Inc. Tatsumori Ltd., trade name), SP-0.3B, SP- 1B ( Fuso Chemical Co., Ltd., trade name ) And the like.
In addition, an average particle diameter can be calculated | required by calculating 50% average particle diameter (D50) by a laser diffraction method. The same applies to other components in the present specification.

  The blending amount of the silica particles (B) is preferably contained in the range of 30 to 90% by mass in the epoxy resin composition, and if the content is less than 30% by mass, the strength may not be sufficiently secured, When it exceeds 90 mass%, a viscosity will rise and workability | operativity may fall.

  Moreover, this (B) silica particle can obtain the insulation reliability and mechanical strength of the hardened | cured material which were further excellent by giving the surface modification by the addition process of the coupling agent in a resin composition. . Examples of coupling agents that can be used here include silane coupling agents, titanium coupling agents, aluminum coupling agents, and the like. A ring agent is preferred.

  Examples of the aminosilane coupling agent include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-aminoethylaminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N -3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane may be mentioned, and these may be used alone or in combination of two or more.

  The (C) acid anhydride used in the present invention can be used without particular limitation as long as it has an acid anhydride group in the molecule and is used as a curing agent for epoxy resins. For example, hexahydrophthalic anhydride Examples include acid, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride and the like. These curing agents can be used alone or in admixture of two or more.

  The (D) curing accelerator used in the present invention is particularly limited as long as it has an action of promoting the reaction between (A) epoxy resins or between (A) epoxy resin and (C) acid anhydride. Rather than those generally used as curing accelerators, for example, imidazoles such as 2-ethyl-4-ethylimidazole and 1-cyanoethyl-2-ethyl-4-ethylimidazole, benzyldimethylamine, 2, Tertiary amines such as 4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU) and its octyl salt, triethylphosphine, triphenylphosphine, diphenylphosphine A quaternary ammonium salt etc. are mentioned, These can be used individually or in mixture of 2 or more types.

  The blending amount of the (D) curing accelerator is preferably in the range of 0.3 to 5 parts by weight with respect to 100 parts by weight of the (C) acid anhydride, and the blending amount is less than 0.3 parts by weight. If it is, the curing time may be long and the curing characteristics may not be sufficiently improved, and if it exceeds 5 parts by mass, the reaction is fast and the pot life is shortened, which is not preferable.

  As the fine resin particles (E) used in the present invention, those having an average particle diameter of 0.1 to 0.5 μm made of a thermosetting resin or a thermoplastic resin can be used. Examples of such resin fine particles include thermosetting resin fine particles such as epoxy resin, polyamide resin, and phenol resin, polypropylene (PP), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyethylene terephthalate (PET), poly Examples include thermoplastic resin fine particles such as butylene terephthalate (PBT), and core-shell rubber composed of two layers of a core layer and a shell layer. By blending these resin fine particles, mechanical strength and insulation reliability can be further improved. it can. Moreover, these can be used individually or in mixture of 2 or more types.

  The blending amount of the resin fine particles (E) is preferably in the range of 0.05 to 5 parts by mass with respect to 100 parts by mass of the silica particles (B). Strength such as strength cannot be sufficiently obtained, and if it exceeds 5 parts by mass, the viscosity of the resin composition is high, impregnation becomes poor, and nests are likely to be formed.

  As the (F) titanium oxide fine particles used in the present invention, generally commercially available titanium dioxide fine particles which are used as an additive compound in the resin composition can be used. The titanium oxide fine particles preferably have an average particle size of 0.05 to 0.3 μm. For example, PT501R (Ishihara Sangyo Co., Ltd., trade name), KA-15 (Titanium Industry Co., Ltd. trade name). The mechanical strength and insulation reliability can be further improved by blending this titanium oxide. Moreover, these can be used individually or in mixture of 2 or more types.

  The blending amount of the (F) titanium oxide fine particles is preferably in the range of 0.05 to 5 parts by weight with respect to 100 parts by weight of the (B) silica particles, and the blending amount is less than 0.05 parts by weight. When the amount of the resin composition exceeds 5 parts by mass, the resin composition has a high viscosity, impregnation properties are deteriorated, and nests are likely to be generated.

  The epoxy resin composition for impregnating a mold coil of the present invention contains alumina, magnesia, boron nitride, which is generally blended with this type of composition in addition to the above components, as long as the effects of the present invention are not impaired. Aluminum hydroxide, water as inorganic fillers such as aluminum nitride, silicon nitride, talc, calcium carbonate, titanium white, clay, bengara, glass fiber, carbon fiber, coupling agent, antifoaming agent, pigment and other additives and flame retardant Magnesium oxide, antimony trioxide and the like can be blended as necessary.

  In preparing the epoxy resin composition of the present invention as a casting material, it can be obtained by uniformly mixing the above-described components. Preferably, (A) the epoxy resin and (B) silica particles The essential component and (E) resin fine particles, (F) titanium oxide fine particles, and other components to be blended as necessary are mixed thoroughly to form a main component, and then (C) acid anhydride is added to the main component in advance. (D) It can manufacture by mixing uniformly the hardening | curing agent component which mixed the essential component of hardening accelerator, and the component mix | blended as needed. At this time, an inorganic filler may be added to the curing agent component.

  The epoxy resin composition for impregnation thus obtained can impart excellent characteristics and reliability when applied to sealing, coating, insulation, etc. of electrical equipment parts such as coils and IC chips. . Among them, it can be preferably used for cast impregnation of a molded coil requiring insulation reliability, particularly an ignition coil.

  The molded coil device of the present invention is obtained by impregnating and curing a coil with the epoxy resin composition for impregnating a molded coil of the present invention. As such a mold coil device, a coil in which a coated conductor wire having a diameter of 30 μm or less, which is disposed in a plastic case having a diameter of 2.0 cm or less, is wound around an iron core is impregnated and cured with the epoxy resin composition for impregnating the mold coil. It is preferable that the resin occupying volume in the ignition coil is 30% or less.

  As a resin composition for this type of ignition coil, pulverized silica having a particle diameter of 8 μm or less, preferably 6 μm or less has been generally used because of its impregnation properties. When the diameter of the silica particles is increased, the filler is precipitated in the resin, and the strength of the cured product is reduced, making it difficult to use as a product.

  The molded coil device of the present invention is obtained by impregnating and curing a coil by casting using the epoxy resin composition for impregnating a molded coil of the present invention. To obtain this molded coil device Can be produced by casting and curing the epoxy resin composition of the present invention to electrical / electronic parts such as coils according to a conventional method in a two-component epoxy resin.

  Hereinafter, the present invention will be described based on examples.

( Reference Example 1 )
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, 200 parts by mass and fine particles of FB942 (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name; average particle size 16 μm) as silica particles As silica, SP-1B (average particle size 1 μm, manufactured by Fuso Chemical Co., Ltd., trade name) 10 parts by mass, as antifoaming agent TSA720 (produced by Toshiba Silicone Co., Ltd., trade name) 0.1 parts by mass, silane coupling As the agent, 0.5 part by mass of TSL8350 (Toshiba Silicone Co., Ltd., trade name) was mixed to obtain a main agent.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

  In addition, it showed in Table 1 about the mixing | blending of the component of the obtained resin composition. The same applies to the following examples and comparative examples.

( Reference Example 2 )
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, 200 parts by mass and fine particles of FB950 (trade name; average particle diameter 25 μm, manufactured by Denki Kagaku Kogyo Co., Ltd.) as silica particles 10 parts by mass of SP-1B (average particle size: 1 μm, manufactured by Fuso Chemical Co., Ltd., trade name) as silica, 0.1 part by mass of TSA720 (trade name: manufactured by Toshiba Silicone Co., Ltd.), silane coupling agent As a main ingredient, 0.5 part by mass of TSL8350 (Toshiba Silicone Co., Ltd., trade name) was mixed.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

( Reference Example 3 )
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as the bisphenol A diglycidyl ether type epoxy resin, 200 masses as the silica particles, Furex E-1 (trade name; average particle size: 15 μm, manufactured by Tatsumori Co., Ltd.) 10 parts by mass of SP-1B (manufactured by Fuso Chemical Co., Ltd., trade name; average particle size 1 μm) as part and fine silica, 0.1 part by mass of TSA720 (trade name, manufactured by Toshiba Silicone Co., Ltd.), silane As a coupling agent, 0.5 part by mass of TSL8350 (Toshiba Silicone Co., Ltd., trade name) was mixed to obtain a main agent.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

( Reference Example 4 )
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, 185 parts by mass and fine particles of FB942 (manufactured by Denki Kagaku Kogyo, trade name; average particle size 16 μm) as silica particles As silica, SP-1B (manufactured by Fuso Chemical Co., Ltd., trade name; average particle size 1 μm) 10 parts by mass, as aluminum hydroxide, 15 parts by weight of Hijilite H42M (manufactured by Showa Denko KK, trade name), as an antifoaming agent 0.1 parts by mass of TSA720 (trade name, manufactured by Toshiba Silicone Co., Ltd.) and 0.5 parts by mass of TSL8350 (trade name, manufactured by Toshiba Silicone Co., Ltd.) as a silane coupling agent were mixed to obtain a main agent.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

( Example 1 )
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, 200 parts by mass and fine particles of FB942 (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name; average particle size 16 μm) as silica particles 10 parts by mass of SP-1B (trade name; average particle size: 1 μm) as silica, 3 parts by mass of PT501-R (Ishihara Sangyo Co., Ltd., trade name) as titanium oxide, and TSA720 (as an antifoaming agent) Toshiba Silicone Co., Ltd., product name) 0.1 parts by mass, and TSL8350 (Toshiba Silicone Co., Ltd., product name) 0.5 parts by mass as a silane coupling agent were mixed to obtain a main agent.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

( Reference Example 5 )
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, 200 parts by mass and fine particles of FB942 (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name; average particle size 16 μm) as silica particles 10 parts by mass of SP-1B (average particle size: 1 μm, manufactured by Fuso Chemical Co., Ltd., trade name) as silica, 2 parts by mass as resin fine particles, TSA720 (trade name: manufactured by Toshiba Silicone Co., Ltd.) 0.1 As a mass part, 0.5 mass part of TSL8350 (Toshiba Silicone Co., Ltd., trade name) was mixed as a silane coupling agent to obtain a main agent.

  Next, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as an acid anhydride is mixed with 0.5 parts by mass of 2E4MZ-CN (trade name, manufactured by Shikoku Chemicals Co., Ltd.), which is a curing accelerator. An epoxy resin composition for impregnating a mold coil was produced by adding 30 parts by mass of this curing agent to 100 parts by mass of the main agent.

(Comparative Example 1)
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, 200 parts by mass of crystallite AA (trade name; average particle size: 7 μm, manufactured by Tatsumori Co., Ltd.) as silica As a foaming agent, 0.1 part by mass of TSA720 (manufactured by Toshiba Silicone Co., Ltd., trade name) and 0.5 part by mass of TSL8350 (Toshiba Silicone Co., Ltd., trade name) as a silane coupling agent were mixed to obtain a main agent.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

(Comparative Example 2)
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, 200 parts by mass of FB942 (trade name; average particle diameter 16 μm, manufactured by Denki Kagaku Kogyo Co., Ltd.) as silica particles, 0.1 parts by mass of TSA720 (trade name, manufactured by Toshiba Silicone Co., Ltd.) was used as a foaming agent, and 0.5 parts by mass of TSL8350 (Toshiba Silicone Co., Ltd., trade name) was mixed as a silane coupling agent to obtain a main agent.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

(Comparative Example 3)
100 parts by mass of EP4100E (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) as a bisphenol A diglycidyl ether type epoxy resin, and 200 parts by mass of crystallite AA (trade name: average particle diameter 7 μm, manufactured by Tatsumori Industry Co., Ltd.) as silica particles 10 parts by mass of core-shell rubber having an average particle size of 0.3 μm as resin fine particles (manufactured by Ganz Kasei Co., Ltd., trade name: AC-3355) and 0.1 mass by weight of TSA720 (manufactured by Toshiba Silicone Co., Ltd., trade name) Part and 0.5 parts by mass of TSL8350 (Toshiba Silicone Co., Ltd., trade name) as a silane coupling agent were mixed to obtain a main agent.

  Next, separately from this, 100 parts by mass of HN5500E (trade name, manufactured by Hitachi Chemical Co., Ltd.) as the acid anhydride, 0.5 mass of 2E4MZ-CN (product name, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator Parts were mixed to obtain a curing agent, and 30 parts by mass of this curing agent was added to 100 parts by mass of the main agent to produce an epoxy resin composition for mold coil impregnation.

(Test example)
Evaluation of glass transition point, bending strength, and dielectric breakdown strength of cured products obtained by heat curing the epoxy resin compositions for mold coil impregnation obtained in Reference Examples 1 to 5, Example 1 and Comparative Examples 1 to 3 The results are also shown in Table 1.

* 1 Viscosity of liquid mixture: The viscosity immediately after mixing the main agent and the curing agent was measured using a B-type viscometer under the conditions of 25 ° C. and 12 rpm.
* 2 Main agent sedimentation: The resin was put in a 1 L round can up to a height of 12 cm, and the degree of filler deposition after standing at 100 ° C. for 1 hour and after standing for 2 hours was evaluated by inserting a spatula.
None: No deposition, little: Soft deposition, Sedimentation: Hard deposition * 3 Coil impregnation property: An epoxy resin composition was vacuum injected into an ignition coil and cured, and then evaluated by observing a cross section of the coil.
Good: No voids, Slightly good: Number of voids, with continuous voids * 4 Glass transition point: Measured by raising the temperature from room temperature to 185 ° C. at a temperature rise of 15 degrees / min by the TMA method.
* 5 Bending strength: measured at a temperature of 25 ° C. according to JIS C 2105.
* 6 Dielectric breakdown voltage: A needle electrode (Ogella needle, needle tip curvature radius: 5 μm) was embedded in the epoxy resin composition so that the distance between the insulations was 2 mm, and cured. Various voltages were applied to the needle electrode, the dielectric breakdown lifetime (Vt characteristic) was acquired, and the dielectric breakdown voltage at 100 hours and 1000 hours was shown.

  From these results, the epoxy resin composition for impregnating a mold coil of the present invention has a good workability and a resin composition with a good impregnation property, and the cured product is excellent in mechanical strength and insulation reliability. Therefore, the molded coil device obtained using this resin composition has high device reliability. Further, since no special and expensive components are used as the raw material, the raw material can be easily procured and can be manufactured at a low cost.

Claims (5)

Using (A) an epoxy resin, (B) silica particles, (F) a main component containing titanium oxide fine particles as essential components, (C) an acid anhydride, and (D) a curing accelerator as essential components an epoxy resin composition comprising a curing agent component containing, in that it consists,
As the (B) silica particles, particles having an average particle size of 10 to 30 μm and particles having an average particle size of 0.01 to 1.5 μm are used in combination, and the epoxy resin composition has an average particle size of 10 to 30 μm. only it contains the particles 30 to 85% by mass,
A mold comprising 0.05 to 5.0 parts by mass of fine particles having an average particle size of 0.05 to 0.3 μm as the titanium oxide fine particles (F) with respect to 100 parts by mass of the silica particles (B). An epoxy resin composition for coil impregnation. 2. The epoxy resin composition for mold coil impregnation according to claim 1 , wherein the silica particles (B) are spherical silica particles. (B) the silica particles, silane-based claim 1 or 2 molded coil impregnating epoxy resin composition described, characterized in that it is surface treated with a coupling agent. A molded coil apparatus, wherein the coil is impregnated and cured with the epoxy resin composition for impregnating a molded coil according to any one of claims 1 to 3 . A pen formed by impregnating and curing a coil in which a molded coil device is disposed in a plastic case having a diameter of 2.0 cm or less and wound with a coated conductor having a diameter of 30 μm or less around an iron core with the epoxy resin composition for impregnating the mold coil. 5. The molded coil device according to claim 4 , wherein the molded coil device is a type of ignition coil, and a resin occupied volume in the ignition coil is 30% or less.