JP2889322B2 - Solid electrolytic capacitors - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to a solid electrolytic capacitor provided with a resin and having excellent electric characteristics.

(Prior Art) As shown in FIG. 1, a solid electrolytic capacitor to which the present invention relates is formed by subjecting an anode body 1 made of a metal having a valve action such as tantalum, aluminum and niobium to a chemical conversion treatment to form a dielectric layer 2. After the formation, the semiconductor layer 3 and the cathode layer 4 are further formed on the surface thereof, and the cathode layer 4 is connected to the external lead frame 5.
The anode body lead 7 connected to the anode body 1 is bonded to the anode external lead 8 with solder 9, and the outer peripheral surface thereof is exteriorly covered with an exterior resin 10. ing.

(Problems to be Solved by the Invention) (Problems to be Solved by the Invention) However, conventionally, the cathode layer is formed using a normal conductive paste, and the performance of the conductive paste of the cathode layer causes the performance of the solid electrolytic capacitor to be reduced. There is a disadvantage that the electrical characteristics after moisture resistance are deteriorated.

The present invention has been made in order to solve the above-mentioned drawbacks, and an object of the present invention is to provide a solid electrolytic capacitor which is excellent in electric characteristics after moisture resistance despite being covered with a resin.

[Constitution of the Invention] (Means for Solving the Problems) The present inventors have conducted intensive studies to achieve the above object, and as a result, the use of a conductive paste having a composition described later has shown that the adhesive property of the cathode layer can be improved. It has been found that a solid electrolytic capacitor which is excellent in electric resistance and is hardly deteriorated in electric characteristics after moisture resistance can be obtained, and the present invention has been completed.

That is, the present invention provides a solid electrolytic capacitor in which a dielectric layer, a semiconductor layer, and a cathode layer are sequentially formed on an anode body made of a metal having a valve action, and is packaged using a resin. A solid electrolytic capacitor comprising a modified resin comprising a hydroxystyrene resin and an epoxy resin, (B) a conductive powder and a fine silica-based powder, and (C) a conductive filler containing a porous filler as an essential component. It is.

 Hereinafter, the present invention will be described in detail.

As the modified resin (A) comprising the polyparahydroxystyrene resin and the epoxy resin used in the present invention, the polyparahydroxystyrene resin and the epoxy resin may be simply dissolved and mixed, or if necessary, may be partially reacted with each other by a heating reaction. It is also possible to combine them. If necessary for the reaction, a curing catalyst can be used. Further, the working viscosity can be improved by dissolving these component resins in a common solvent.

The polyparahydroxystyrene resin used here is a resin represented by the following formula.

(In the formula, n represents an integer of 25 to 90.) Examples of such a resin include Marcalinker M (trade name, manufactured by Maruzen Petrochemical Co., Ltd.) and the like.
It has a hydroxyl equivalent of about 120 at ~ 8000. As the epoxy resin used for the modified resin, the following bisphenol diepoxides are industrially produced and can be effectively used in the present invention. Epicoat 827,828,834,1001,1002,1007,1009 (manufactured by Shell Chemical Company, trade name), DER330,331,332,334,335,336,337,660
(Trade name of Dow Chemical Company), Araldite GY250,260,
280,6071,6084,6097,6099 (manufactured by Ciba Geigy, trade name), EPI-REZ510,5101 (manufactured by JONE DABNEY, trade name), Epicron 810,1000,1010,3010 (manufactured by Dainippon Ink and Chemicals, Product name) and EP series (product name, manufactured by Asahi Denka Co., Ltd.). Further, by using a novolak epoxy resin having an average number of epoxy groups of 3 or more, for example, a hot
0 ° C.) can be further improved. Those having a molecular weight of 500 or more are suitable as these novolak epoxy resins. Examples of industrially produced novolak epoxy resins include the following. Araldite EPN1138,1139, ECN 1273,1280,1
299 (manufactured by Ciba Geigy, trade name), DEN431,438 (manufactured by Dow Chemical Company, trade name), Epicoat 152,154 (manufactured by Shell Chemical Company, trade name), ERR-0100, ERRB-0447, ERLB-0
488 (manufactured by Union Carbide, trade name), EOCN series (manufactured by Nippon Kayaku Co., Ltd.) and the like, and these epoxy resins can be used alone or in combination of two or more.

It is desirable that the modified resin composed of the polyparahydroxystyrene resin and the epoxy resin is dissolved and mixed with the following solvent. Solvents that can be used here include dioxane, hexane, benzene, toluene, solvent naphtha, industrial gasoline, cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, diethylene glycol diethyl ether, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like are used, and these are used alone or in combination of two or more.

As the conductive powder (B) and the fine silica-based powder used in the present invention, a conductive powder and a fine silica powder are used in combination. Silver powder, silver-plated copper powder, copper powder, nickel powder, carbon and the like are used as the conductive powder. As the fine silica powder, for example, AEROSIL (trade name, manufactured by Nippon AEROSIL Co., Ltd.) and the like can be mentioned, and those having a particle size of 1 μm or less are preferable.

The porous filler (C) used in the present invention is used in combination to prevent migration, and is not particularly limited as long as it is a porous filler. For example, Talcite (Kyowa Chemical Industry Co., Ltd.), Ketjen Black (Carbon Black, Ketjen Co., Ltd.), Celite (Diatomaceous earth, Johns)
Manville (trade name) and the like.
A mixture of more than one species can be used.

The conductive paste used in the present invention contains a modified resin composed of a polyparahydroxystyrene resin and an epoxy resin, a conductive powder and a fine silica-based powder, and a porous filler as essential components, but does not violate the object of the present invention. In the above, if necessary, an antifoaming agent and other additives can be added and blended.

After sufficiently mixing these components according to a conventional method, the mixture is further kneaded with, for example, a three-roll mill, then defoamed under reduced pressure, diluted with an acetate-based solvent, and dipped in a solid electrolytic capacitor element to form a cathode layer. Then, after joining the cathode layer and the lead frame with a conductive adhesive, the anode body lead is soldered to the anode outer lead, and the resin is externally covered by a molding method or a dipping method to manufacture a solid electrolytic capacitor. it can.

(Function) The solid electrolytic capacitor of the present invention uses a modified resin composed of a polyparahydroxystyrene resin and an epoxy resin, and by using a porous filler in combination with the modified resin, provides excellent adhesiveness and electrical properties after moisture resistance. It was something that could be done.

(Examples) Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “parts” means “parts by weight” unless otherwise specified.

Example 1 Epoxy resin 1001 (manufactured by Shell Chemical Co., Ltd., trade name) 37.5 times of epoxy resin and 10 parts of Marcalinker M (manufactured by Maruzen Petrochemical Co., Ltd., trade name) of polyparahydroxystyrene resin were mixed in 103 parts of diethylene glycol diethyl ether. At 100
The mixture was subjected to a dissolution reaction at 1 ° C. for 1 hour to obtain a viscous resin. This resin
In 22 parts, an amine complex of boron trifluoride 1.0 as a catalyst
Parts, additive 0.03 parts, silver powder 57 parts, AERYL # 200
(Nippon Aerosil Co., Ltd., product name) 2.0 parts, Talcite
A conductive paste was manufactured by mixing 0.1 part and 50 parts of butyl acetate.

Example 2 15.8 parts of Epicoat 828 (trade name, manufactured by Shell Chemical Co., Ltd.) of epoxy resin and 10 parts of Marcalinker M (trade name, manufactured by Marumae Petrochemical Co., Ltd.) of polyparahydroxystyrene resin were combined with 56 parts of butyl cellosolve acetate. The solution was reacted at 100 ° C. for 1 hour to obtain a viscous resin. In 22 parts of this resin,
1.0 part of amine complex of boron trifluoride, silver powder 5 as catalyst
7 parts, Aerial # 200 (see above) 2.5 parts, Talcite 0.1
And 50 parts of butyl acetate to obtain a conductive paste.

Example 3 66 parts of epoxy resin EOCN103S (trade name, manufactured by Nippon Kayaku Co., Ltd.) and 34 parts of Marukalinker M (supra) of polyparahydroxystyrene resin. Butyl carbitol acetate 11
A dissolution reaction was performed in 7 parts at 100 ° C for 1 hour to obtain a viscous resin. To 22 parts of this resin, 1.0 part of an amine complex of boron trifluoride as a catalyst, 57 parts of silver powder, AERYL # 200 (see above)
2.0 parts, 0.1 part of talcite, and 50 parts of butyl acetate were mixed to produce a conductive paste.

Comparative Example A commercially available epoxy resin-based conductive paste for a solvent-type semiconductor was obtained.

Using the conductive paste obtained in Examples 1 to 3 and Comparative Example, a solid electrolytic capacitor is dipped therein to form a cathode layer, and then the lead frame and the cathode layer are joined, and a resin is formed by a molding method. By covering with an exterior, a solid electrolytic capacitor was manufactured. The solid electrolytic capacitor thus obtained was tested for adhesion strength and moisture current leakage. The results are shown in Table 1. As shown in Table 1, the present invention was excellent, and the effects of the present invention were confirmed.

[Effects of the Invention] As is clear from the above description and the results in Table 1, the solid electrolytic capacitor of the present invention has excellent adhesive properties and electrical properties after moisture resistance, and has excellent electrical properties even when packaged with a resin. The decline was slight.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view for explaining a solid electrolytic capacitor to which the present invention relates. 1 ... Anode body, 2 ... Dielectric layer, 3 ... Semiconductor layer, 4 ...
... Cathode layer, 5 ... Cathode lead frame, 6 ... Conductive adhesive, 7 ... Anode lead, 8 ... Anode outer lead, 9
…… Solder, 10 …… Exterior resin.

Claims (1)

(57) [Claims] 1. A solid electrolytic capacitor in which a dielectric layer, a semiconductor layer, and a cathode layer are sequentially formed on an anode body made of a metal having a valve action, and are packaged using a resin. A solid electrolytic capacitor comprising a conductive resin containing a modified resin comprising a styrene resin and an epoxy resin, (B) a conductive powder and a fine silica-based powder, and (C) a porous filler.