JP2013118338A - Resin composition for film capacitor and film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for a film capacitor mold, having good capacitor characteristics, particularly good appearance, no void-occurrence, less moisture permeability of a cured product, a small change rate in dielectric resistance, and excellent reliability.SOLUTION: A resin composition for a film capacitor contains, as an essential component, (A) a liquid epoxy resin, (B) a dicyclopentadiene-type epoxy resin, (C) an acid anhydride curing agent and (D) an inorganic filler, where when the total amount of the (A) liquid epoxy resin and the (B) dicyclopentadiene-type epoxy resin is 100 pts.mass, mixing amounts of the components are as follows: the (A) liquid epoxy resin is 50 to 90 pts.mass, the (B) dicyclopentadiene-type epoxy resin is 10 to 50 pts.mass, the (C) acid anhydride curing agent is 75 to 120 pts.mass and the (D) inorganic filler is 500 to 1500 pts.mass.

Description

  The present invention relates to a resin composition for a film capacitor and a film capacitor, and relates to a liquid epoxy resin composition suitable for producing a film capacitor and a film capacitor excellent in characteristics such as moisture permeability obtained by using the resin composition. .

  In the conventional film capacitor manufacturing method, for both foil type and metallized type, first, a film is wound up to form a film capacitor element, and then the film capacitor element is hot-pressed to reduce the space between the films. In general, there has been a method (Patent Document 1) in which resin dip is performed with an epoxy resin, and the air inside the film capacitor element is replaced with resin by evacuation to impregnate the resin between the films.

  After that, an injection mold having a cavity recess capable of accommodating the film capacitor element is provided, the film capacitor element is accommodated in the cavity recess, and the injection mold is clamped to form a cavity enclosing the film capacitor element. The polyphenylene sulfide resin is injected into the cavity, and the film capacitor element housed in the cavity is sealed with resin to form an outer cover of the film capacitor element, and the resin between the wound films of the film capacitor element There has also been proposed a method of impregnating (Patent Document 2).

  In addition, an epoxy resin composition in which an inorganic water-absorbing material is added to a composition having a moisture diffusion coefficient of a predetermined range as an epoxy resin having a low moisture permeability of the cured product and suitable as a premold type hollow package material ( Patent Document 3) is known.

Japanese Patent Publication No. 5-77324 JP-A-7-161578 JP 7-216196 A

  However, in the method of Patent Document 1, heat press is performed in order to increase the capacity. However, this process causes the film forming the film capacitor element to be subjected to thermal stress or pressure stress, and the film is deteriorated. There is a problem that the stability of the capacity and the impact resistance are reduced.

In addition, in the method of Patent Document 2, PPS (polyphenylene sulfide) injection molding requires a high pressure of 100 to 250 kgf / cm ² and a high temperature of 300 ° C., so that the film capacitor element is damaged. In order to prevent possibility, there existed problems, such as requiring preliminary sealing before this sealing.

  Furthermore, although the epoxy resin excellent in moisture permeability is proposed by patent document 3, this epoxy resin is not described about the application to a film capacitor, and molding conditions are 150-180 degreeC and high temperature. For this reason, when applied, the film capacitor element deteriorates, so that it cannot be diverted as it is.

  The present invention has been made in view of such circumstances, and has excellent capacitor characteristics, particularly good appearance, no voids, low moisture permeability of the cured product, low change rate of insulation resistance, and excellent reliability. An object of the present invention is to provide a film capacitor.

  As a result of repeated research on film capacitors, the present inventors have found that the above-described problems can be solved by using a specific resin composition, and have completed the present invention.

  That is, the resin composition for a film capacitor of the present invention comprises (A) a liquid epoxy resin, (B) a dicyclopentadiene type epoxy resin, (C) an acid anhydride curing agent, and (D) an inorganic filler. It is a resin composition for film capacitors contained as an essential component, and the blending amount of each component when the total amount of the (A) liquid epoxy resin and (B) dicyclopentadiene type epoxy resin is 100 parts by mass. The (A) liquid epoxy resin 50 to 90 parts by mass, the (B) dicyclopentadiene type epoxy resin 10 to 50 parts by mass, the (C) acid anhydride curing agent 75 to 120 parts by mass, and the (D) inorganic The filler is 500 to 1500 parts by mass.

  The film capacitor of the present invention is characterized in that a film capacitor element is sealed using the resin composition for a film capacitor.

  Since the resin composition for a film capacitor of the present invention is excellent in moldability and its cured product is excellent in moisture permeability, a film capacitor excellent in reliability can be obtained by applying this resin composition. .

It is a figure explaining the manufacturing method of the film capacitor of the present invention. It is sectional drawing of the film capacitor of this invention.

  Hereinafter, the resin composition for film capacitors and the film capacitor of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited at all by those drawings.

  FIG. 1 is a diagram for explaining a method for producing a film capacitor of the present invention. Here, the mold used for manufacturing the film capacitor is composed of a lower mold 1 and an upper mold 2, and the mold has recesses formed in the lower mold 1 and the upper mold 2, respectively. The recess is a cavity. A film capacitor is manufactured by performing injection molding using the resin composition melted in the cavity.

  First, as shown in FIG. 1A, a film capacitor element 3 is disposed in a recess of a lower mold 1 having a recess of a predetermined shape and temperature controlled, and a liquid epoxy resin composition 4 is disposed thereon. The upper mold 2 having the injection nozzle 5 is covered, the joint between the lower mold 1 and the lower mold 1 is hermetically sealed, and the inside of the cavity formed by the lower mold 1 and the upper mold 2 is a vacuum pump or the like (illustrated) Is omitted under reduced pressure) to reach 10 Torr. Here, the injection nozzle 5 is connected to the sprue 2a for introducing the resin provided in the upper mold 2 into the cavity at the front end portion 5c, and the entire nozzle is configured to be movable up and down. Further, the nozzle tip 5c can be opened and closed by raising and lowering the plunger 5b concentrically disposed in the nozzle main pipe 5a.

  Then, as shown in FIG. 1 (b), when the inside of the cavity is kept at a certain degree of reduced pressure, the tip portion 5c of the injection nozzle 5 is opened, and the liquid epoxy resin composition 4 is placed between the lower mold 1 and the upper mold. Injection into the cavity between the mold 2. After filling the cavity with a liquid epoxy resin composition 4 by injection, the lower mold 1 and the upper mold 2 are heated to an appropriate temperature and cured, and the electrode terminal 3a of the film capacitor element 3 is formed by the upper mold. 2 and the lower mold 1 are held without a gap.

  When the curing is completed, the lower mold 1 and the upper mold 2 are opened, and the film capacitor as a molded product is taken out. The film capacitor 11 obtained here has, for example, a structure in which the film capacitor element 3 is covered and protected with a cured product 12 of a liquid epoxy resin composition, as shown in FIG. The end portion protrudes out of the cured product 12 and can be connected to other devices.

  Here, the film capacitor element 3 is a capacitor formed by winding a film and an electrode foil, and protrudes so that the metal electrode 3a extends in the opposite direction to the capacitor body in parallel from the upper and lower surfaces thereof. Yes. The illustrated film capacitor element 3 is an example, and the film capacitor element 3 in the present invention can be used without particular limitation as long as it is a known film capacitor element.

  Thus, in the manufacturing method of the present invention using the injection molding, the supply of the liquid epoxy resin composition 4 to the film capacitor 3 and the sealing molding can be continuously performed efficiently, and the unfilled portion and the void can be performed. In addition, it is possible to obtain a sealed molded body having a good appearance. Thus, when using a thermosetting resin, after setting injection temperature to low temperature, it is preferable to fill a high temperature metal mold | die and harden | cure.

  As the injection filling conditions, the injection temperature is preferably 50 to 70 ° C. If it is less than 50 ° C., the fluidity will deteriorate. On the other hand, if it is higher than 70 ° C., it is not preferable in that a part of the curing reaction proceeds in the injection nozzle. The filling rate is preferably 0.2 to 5.0 L / min. If it is less than 0.2 L / min, it is not preferable from the viewpoint of productivity. On the other hand, if it is 5.0 L / min, a resin entrainment void may occur in the sealed molded body, which is not preferable.

  As a pressurizing condition, 0.2 to 10 MPa is preferable. If it is less than 0.2 MPa, unfilled portions and voids are generated. On the other hand, if it is greater than 10 MPa, the film capacitor element is damaged.

  The injection nozzle or the like may be equipped with a heating means such as a heater that can heat the resin to a desired temperature for maintaining the resin.

  The heat curing of the resin composition is preferably performed at 90 to 110 ° C. for about 5 to 25 minutes. Within this range, the curing reaction proceeds slowly, and the resin composition is uniformly impregnated and filled in the voids of the film capacitor element.

  The temperature of the mold is preferably 90 to 120 ° C. Under 90 ° C., insufficient curing occurs. On the other hand, if it is higher than 120 ° C., the film capacitor element is damaged by heat. The lower mold 1 and the upper mold 2 are preferably made of a metal having heat resistance and corrosion resistance such as stainless steel.

  Further, it is preferably taken out from the mold and post-cured as necessary. For example, it is carried out at 100 ° C. for 2 hours.

  Next, the liquid epoxy resin composition of the present invention used in the above-described production method will be described in detail.

  The subject of the present invention is to provide a film capacitor which exhibits a stable insulation resistivity, has no moisture permeability, is excellent in reliability, and has a good appearance. The present inventors have found that a film capacitor satisfying the above characteristics can be obtained by sealing and molding the periphery of a film capacitor element with a resin composition containing a predetermined component in a predetermined ratio. is there.

  That is, the liquid epoxy resin composition of the present invention comprises (A) a liquid epoxy resin, (B) a cyclopentadiene type epoxy resin, (C) an acid anhydride curing agent, and (D) an inorganic filler. It is contained as an essential component, and other additives are blended as necessary.

  Here, the liquid epoxy resin (A) used in the present invention has more than one epoxy group per molecule, and preferably has two epoxy groups per molecule. Examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, novolac type epoxy resins, glycidyl ester type epoxy resins, and alicyclic epoxy resins other than dicyclopentadiene type. And glycidyl ether. These can be used alone or in admixture of two or more.

（式中、Ｒ^１及びＲ^２は、それぞれ独立して、水素原子及び置換基を有していてもよい炭素数１〜１０の一価の炭化水素基から選ばれ、ｎは０〜１０の整数を示し、ｍは０〜６の整数を示す。）で示されるエポキシ樹脂等が挙げられる。 The dicyclopentadiene type epoxy resin (B) used in the present invention has a main skeleton derived from cyclopentadiene, which is a cyclic diene having a five-membered ring structure, and more than one epoxy group per molecule. It is preferable that it has 2 epoxy groups per molecule. As the dicyclopentadiene type epoxy resin, for example, the following general formula (I)

(In the formula, R ¹ and R ² are each independently selected from a hydrogen atom and a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and n is 0 to 10). And an epoxy resin represented by the following formula: m represents an integer of 0 to 6.

R ¹ in the general formula (I) is, for example, a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, or a tert-butyl group; a vinyl group, an allyl group, or a butenyl group. Alkenyl groups such as halogenated alkyl groups, amino group-substituted alkyl groups, mercapto group-substituted alkyl groups; substituted or unsubstituted monovalent hydrocarbon groups having 1 to 5 carbon atoms, such as methyl Group, an alkyl group such as an ethyl group and a hydrogen atom are preferable, and a methyl group and a hydrogen atom are more preferable.

Examples of R ² include a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, and a tert-butyl group; an alkenyl group such as a vinyl group, an allyl group, and a butenyl group; A substituted or unsubstituted monovalent hydrocarbon group having 1 to 5 carbon atoms such as a group, an amino group-substituted alkyl group, a mercapto group-substituted alkyl group; and the like. Among these, a hydrogen atom is preferable. Examples of such an epoxy resin include HP-7200 (manufactured by Dainippon Ink & Chemicals, Inc., trade name) and the like, which are available as commercial products.

  The average molecular weight of the dicyclopentadiene type epoxy resin is 100 to 1000. If it is this range, the point which can prevent that a material leaks from a nozzle at the time of injection molding with favorable mixing property with a hardening | curing agent is excellent.

  In the present invention, it is indispensable to use two types of epoxy resins (A) liquid epoxy resin and (B) dicyclopentadiene type epoxy resin in combination. When the amount is 100 parts by mass, the range is (A) 50 to 90 parts by mass of the liquid epoxy resin and 10 to 50 parts by mass of the dicyclopentadiene type epoxy resin. Here, when the component (A) is less than 50 parts by mass, the viscosity does not decrease, and as a result, the impregnation property is not good, and when it exceeds 90 parts by mass, the moisture resistance reliability of the cured product Decreases and the desired cured product characteristics cannot be obtained.

  The (C) acid anhydride curing agent used in the present invention may be any known acid anhydride curing agent as an epoxy resin curing agent. Specific examples of the acid anhydride curing agent include tetrahydrophthalic anhydride. , Hexahydrophthalic anhydride, methylhexahydrophthalic anhydride and the like.

  The compounding amount of the (C) acid anhydride curing agent is in the range of 75 to 120 parts by mass when the total amount of the component (A) and the component (B) is 100 parts by mass. Moreover, it is preferable to set it as an equivalent of 0.9 to 1.1 times with respect to the epoxy equivalent of a liquid epoxy resin and a dicyclopentadiene type epoxy resin. When blending outside this range, impact resistance and reliability are lowered, which is not preferable.

  The (D) inorganic filler used in the present invention is not particularly limited as long as it is an inorganic filler blended in the resin composition. For example, silica, alumina, silicon nitride, boron nitride, magnesia, boehmite, calcium carbonate , Aluminum hydroxide, talc and the like. These fillers may be used individually by 1 type, and may mix and use 2 or more types. In the present invention, silica powder is preferably used, and the use of spherical silica powder is particularly preferable.

  Here, (D) an inorganic filler contains in the range of 500-1500 mass parts, when the total amount of (A) component and (B) component is 100 mass parts. When the amount of the filler is 500 parts by mass or less, the structure such as a film capacitor element or an electrode is likely to be distorted or damaged due to shrinkage of the cured product. However, it is not preferable because unfilled portions are generated. Within the above range, the cured product has good thermal shock resistance, mechanical strength, and flame retardancy.

  In addition, as the inorganic filler (D) in the present invention, it is preferable to use one kind of filler having different average particle diameters in terms of fluidity at the time of injection. For example, the whole inorganic filler is 100% by mass. It is more preferable that spherical fused silica having an average particle size of 15 to 25 μm is contained in an amount of 70 to 90% by mass and spherical fused silica having an average particle size of 1 to 5 μm is contained in an amount of 10 to 30% by mass. When spherical fused silica is used, it is particularly preferable that the inorganic filler is composed only of the above-described spherical fused silica.

  In addition, when using the above-mentioned spherical fused silica having different average particle diameters, other inorganic fillers can also be contained. In that case, the remaining filler is silica powder composed of fused crushed silica and crystalline silica. Is preferable from the viewpoint of low water absorption and low moisture permeability of the cured product. When blending outside this range, the fluidity at the time of injection is lowered and unfilled portions are generated, which is not preferable.

  Moreover, although this invention makes the said component an essential component, in order to improve a hardening characteristic, (E) hardening accelerator can also be added. There is no restriction | limiting in particular as (E) hardening accelerator used for this invention, Arbitrary things can be suitably selected and used from what was conventionally used as a hardening accelerator of an epoxy resin.

  Examples of the (E) curing accelerator include aromatic dimethylurea, aliphatic dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro-4 -Methylphenyl) -1,1-dimethylurea, ureas such as 2,4-bis (3,3-dimethylureido) toluene, benzyldimethylamine, 1,8-diazabicyclo (5.4.0) undecene-7 , Tertiary amine compounds such as triethylamine, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-phenylimidazole, 2 -Existence of imidazole compounds such as phenyl-4-methylimidazole, triphenylphosphine salt, etc. Phosphine salt compounds. These curing accelerators may be used alone or in combination of two or more. Of these, imidazole-based curing accelerators can be preferably used from the viewpoint of low moisture permeability and moisture resistance reliability.

  (E) The amount of the curing accelerator is usually 0.1 when the total amount of the component (A) and the component (B) is 100 parts by mass from the viewpoint of the balance between curing acceleration and cured resin physical properties. About 10 to 10 parts by mass, preferably 0.4 to 5 parts by mass.

  The liquid epoxy resin composition has a coupling agent (for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, etc.) as long as the effects of the present invention are not impaired. , Mold release agents (eg, synthetic wax, natural wax, linear aliphatic metal salts, acid amides, esters, etc.), colorants (eg, carbon black, cobalt blue, etc.), low stress imparting agents (eg, silicone) Oil, silicone rubber, etc.), an antifoaming agent, etc. may be further blended.

  The liquid epoxy resin composition of the present invention having the above composition preferably has a gel time at 100 ° C. of 5 to 30 minutes. When the gel time is 5 minutes or less, voids are likely to be generated in the cured product, and when it is 30 minutes or more, the shape retainability of the cured product is deteriorated.

  A film capacitor (200 mm × 250 mm, thickness) is formed by an injection molding method in which the resin composition of the present invention is injected into a cavity in which 12 film capacitor elements (60 mm × 35 mm, thickness 60 mm) are placed under the above conditions and then cured. 70 mm) can be manufactured.

  In such a manufacturing method, a liquid epoxy resin composition is supplied and sealed using an upper mold having an injection mechanism on the upper side of the film capacitor element 3 held in the lower mold under a certain reduced pressure. Thus, it is possible to obtain a capacitor device having a good appearance with no unfilled portions and voids. Furthermore, the capacitor device obtained in this way is excellent in all characteristics such as moisture permeability and insulation resistance, and is a highly reliable device.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

(Examples 1-7 and Comparative Examples 1-5)
Each raw material of the blend composition (parts by mass) shown in Table 1 and Table 2 was uniformly stirred and mixed to prepare a liquid epoxy resin composition.

  Next, the film capacitor element 3 is accommodated in the recess of the lower mold 1, the upper mold 2 is aligned, and the liquid epoxy resin composition 4 prepared previously is introduced into the nozzle main pipe 5 a of the injection nozzle 5 of FIG. 1. Then, the inside of the cavity between the lower mold 1 and the upper mold 2 was reached to 10 Torr with a vacuum pump. Next, the plunger 5b is raised, and the resin composition is injected and filled into the cavity at a filling speed of 0.5 L / min and an injection temperature of 60 ° C., and then the lower mold 1 and the upper mold 2 are heated under 0.5 MPa. The resin composition was heated and cured at 100 ° C. for 20 minutes, and the electrode terminal 3a of the film capacitor element 3 was sandwiched between the upper mold 2 and the lower mold part 1 without a gap. Thereafter, the mold was opened (the cured product was taken out of the mold), and post-curing was performed at 100 ° C. for 2 hours to produce a film capacitor. The evaluation results of various properties in each example are shown in Table 1 and Table 2.

  In addition, each raw material component used is as follows.

[Epoxy resin]
(1) R140P (Bisphenol A type epoxy resin manufactured by Mitsui Chemicals, trade name; liquid, epoxy equivalent 188)
(2) jER807 (Bisphenol F type epoxy resin manufactured by Mitsubishi Chemical Corporation, trade name; liquid, epoxy equivalent 170)
(3) HP-7200 (DIC dicyclopentadiene type epoxy resin, trade name; liquid, epoxy equivalent 260)
(4) HP-4032 (Naphthalene skeleton epoxy resin manufactured by DIC, trade name: solid, epoxy equivalent 150)
(5) SR-16H (Glicidyl ether manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name; liquid, epoxy equivalent 157)
(6) BREM-105 (Nippon Kayaku Brominated epoxy resin, trade name; solid, epoxy equivalent 280)
(7) EPOXAN (silicon-modified epoxy resin manufactured by Shin-Etsu Chemical Co., Ltd., trade name; solid, epoxy equivalent 300)

[Curing agent]
(1) HN2000 (manufactured by Hitachi Chemical Co., Ltd., methyltetrahydrophthalic anhydride, trade name; acid anhydride equivalent 166)
(2) HN5500 (Methylhexahydrophthalic anhydride manufactured by Hitachi Chemical Co., Ltd., trade name; acid anhydride equivalent 168)
(3) NH-7000 (Phenol resin manufactured by Nippon Kayaku Co., Ltd., trade name: hydroxyl group equivalent 140)
(4) XL225-3L (phenol resin manufactured by Mitsui Chemicals, trade name; hydroxyl group equivalent 170)

[Defoaming agent]
TSA720 (Momentive Performance Materials Japan, product name)
[Silane coupling agent]
A-187 (Nihon Unicar Co., Ltd. 3-glycidoxypropyltrimethoxysilane, trade name)

[Inorganic filler]
(1) HS-106 (Spherical fused silica manufactured by Micron, trade name; spherical, average particle size 18.2 μm)
(2) SO-C6 (spherical fused silica manufactured by Admafine, trade name: spherical, average particle size 2.2 μm)
[Curing accelerator]
2E4MZ (imidazole manufactured by Shikoku Kasei Co., Ltd., trade name)

<Hardened resin>
(1) Boiling water absorption rate A disc-shaped sample (diameter 50 mm × thickness 3 mm) produced by curing the resin composition at 100 ° C. for 5 hours is immersed in boiling water for 1 hour and cured before and after immersion. Based on the amount of substance, the mass increase with respect to the mass before immersion was calculated as the boiling water absorption rate.
(2) Moisture permeability About a disk-shaped sample (diameter 60 mm × thickness 2 mm) produced by curing the resin composition at 100 ° C. for 5 hours, 85 ° C./85 by the cup method (JIS L 1099). The amount of mass change in an environment of 300% in% RH was calculated, and based on the value, the increase in mass per 1 m ² for 24 hours was calculated as the moisture permeability evaluation characteristic.

(3) Molding appearance The molded film capacitor was arbitrarily cut, the presence or absence of voids on the cut surface was visually confirmed, and evaluated according to the following criteria.
○: No void △: Slightly voided ×: Voided (4) Insulation resistance The insulation resistance between package (PKG) electrodes after 1000 hours in an 85 ° C / 85% RH environment in a molded film capacitor It was measured. From the change rate of the insulation resistance before and after the test, the following criteria were used for evaluation.
○: Change rate of less than 20% △: Change rate of 20% or more and less than 50% ×: Change rate of 50% or more

  As is apparent from Table 1, in Examples 1 to 7, by using an epoxy resin composition that is a combination of a liquid epoxy resin and a dicyclopentadiene type epoxy resin, the change in insulation resistivity after the moisture resistance test, that is, It was possible to obtain a sealed molded body having a small change rate of insulation resistance and a good appearance.

  In contrast, as shown in Table 2, in Comparative Examples 1 to 3 in which no dicyclopentadiene type epoxy resin was used, the rate of change in insulation resistance was large. Further, in Comparative Example 4 in which the filler filling amount was 1500 parts by mass or more, there were many unfilled portions, and the rate of change in insulation resistance was large. Further, when the curing agent is different as in Comparative Example 5, curing at 100 ° C. for 5 hours was insufficient.

DESCRIPTION OF SYMBOLS 1 ... Lower die, 2 ... Upper die, 3 ... Film capacitor element, 4 ... Liquid epoxy resin composition, 5 ... Injection nozzle, 11 ... Film capacitor, 12 ... Hardened | cured material

Claims (7)

A resin composition for a film capacitor comprising (A) a liquid epoxy resin, (B) a dicyclopentadiene type epoxy resin, (C) an acid anhydride curing agent, and (D) an inorganic filler as essential components. And
When the total amount of the (A) liquid epoxy resin and the (B) dicyclopentadiene type epoxy resin is 100 parts by mass, the blending amount of each component is 50 to 90 parts by mass of the (A) liquid epoxy resin, (B) 10 to 50 parts by mass of a dicyclopentadiene type epoxy resin, 75 to 120 parts by mass of the (C) acid anhydride curing agent, and 500 to 1500 parts by mass of the (D) inorganic filler. Resin composition for capacitors.   Furthermore, the resin composition for film capacitors of Claim 1 formed by containing 0.1-10 mass parts of (E) hardening accelerators.   The resin composition for a film capacitor according to claim 2, wherein the curing accelerator is imidazole.   The said (D) inorganic filler consists of 70-90 mass% of inorganic fillers with an average particle diameter of 15-25 micrometers, and 10-30 mass% of inorganic fillers with an average particle diameter of 1-5 micrometers. The resin composition for film capacitors as described.   The resin composition for a film capacitor according to any one of claims 1 to 4, wherein the (B) dicyclopentadiene type epoxy resin has an average molecular weight of 100 to 1,000.   A film capacitor comprising a film capacitor element sealed with the resin composition for a film capacitor according to any one of claims 1 to 5.   The film capacitor element is installed in the mold, then the mold is closed, the resin composition is injected into the mold by an injection molding method, and the resin composition is obtained by heating and curing. Film capacitor.

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