JP2883164B2 - 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 using a resin for an exterior 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, niobium or the like 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, and the cathode layer 4 is connected to the external lead frame 5.
The anode body lead 7 connected to the cathode body 1 is joined to the anode outer lead 8 with solder 9, and the outer peripheral surface of the anode body lead 7 is packaged with a package resin 10. ing.

(Problems to be Solved by the Invention) However, conventionally, the cathode layer is formed by using a normal conductive paste, and the electric characteristics of the solid electrolytic capacitor after moisture resistance are deteriorated due to the performance of the conductive paste of the cathode layer. was there.

The present invention has been made in order to solve the above-mentioned drawbacks, and provides a fixed electrolytic capacitor which has excellent adhesiveness of a cathode layer and excellent electrical properties after moisture resistance despite being covered with a resin. What you want to do.

[Structure of the Invention] (Means for Solving the Problems) The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have excellent adhesiveness by using a conductive paste having a composition described later. The inventors have found that a solid electrolytic capacitor in which a cathode layer can be formed and the electric characteristics of which are hardly deteriorated after moisture resistance is 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 modified resin comprising a hydroxystyrene resin and an epoxy resin; (B) an epoxy resin having a benzophenone-based imide group; (C) a conductive powder and a fine silica-based powder; A solid electrolytic capacitor characterized by being formed by:

 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 the novolak epoxy resin industrially produced include the following. Araldite EPN1138,1139, ECN1273,1280,1299
(Ciba-Geigy, trade name), DEN431,438 (Dow Chemical, trade name), Epicoat 152,154 (Shell Chemical, trade name), ERR-0100, ERRB-0447, ERLB-0488
(Trade name, manufactured by Union Carbide Co., Ltd.) and EOCN series (trade name, manufactured by Nippon Kayaku Co., Ltd.). 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 epoxy resin (B) having a benzophenone-based imide group used in the present invention, any resin having both an epoxy group and a benzophenone-based imide group in a compound may be used.

The mixing ratio of the epoxy resin having a benzophenone-based imide group is desirably 5 to 80% by weight based on the total amount of the resin components [(A) + (B)]. If the amount is less than 5% by weight, there is no effect on the improvement of the adhesive strength.
If the content is more than 10% by weight, the reactivity tends to be poor, which is not preferable.

As the conductive powder (C) 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 (D) acetate solvent used in the present invention includes:
For example, methyl acetate, ethyl acetate, butyl acetate, isopropyl acetate, isoamyl acetate and the like can be mentioned, and these can be used alone or in combination of two or more. The acetate-based solvent is used as one component of the conductive paste solvent.

The conductive paste used in the present invention is a modified resin composed of a polyparahydroxystyrene resin and an epoxy resin, an epoxy resin having a benzophenone-based imide group, a conductive powder, and a fine silica-based powder, and an acetate-based solvent as an essential component. However, an antifoaming agent and other additives can be added and compounded within a range not inconsistent with the object of the present invention and as necessary.

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 into 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 lead is soldered and covered with a resin by a molding method or a dipping method to manufacture a solid electrolytic capacitor.

(Function) The solid electrolytic capacitor of the present invention can form a cathode layer having excellent adhesion by using a modified resin composed of a polyparahydroxystyrene resin and an epoxy resin and an epoxy resin having a benzophenone-based imide group. The electrical properties after moisture resistance were excellent.

(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 33.7 parts of Epicoat 1001 (manufactured by Shell Chemical Co., Ltd.) of epoxy resin, 10 parts of Marukalinker M (manufactured by Maruzen Petrochemical Co., Ltd.) of polyparahydroxystyrene resin, epoxy resin having benzophenone-based imide group 3.75 parts,
100 in 103 parts of diethylene glycol diethyl ether
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
A conductive paste was manufactured by mixing 2.0 parts (trade name, manufactured by Nippon Aerosil Co., Ltd.) and 50 parts of butyl acetate.

Example 2 14.3 parts of Epicoat 828 (trade name, manufactured by Shell Chemical Co., Ltd.) of epoxy resin, 10 parts of Marukalinker M (trade name, manufactured by Marumae Petrochemical Co., Ltd.) of polyparahydroxystyrene resin, epoxy having a benzophenone-based imide group 1.58 parts of resin,
Dissolution reaction was performed in 56 parts of butyl cellosolve acetate 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
, 2.5 parts of AEROGYL # 200 (supra) and 50 parts of butyl acetate to prepare a conductive paste.

Example 3 Epoxy resin EOCN103S (trade name, manufactured by Nippon Kayaku Co., Ltd.) 60
Parts, 34 parts of Marcalinker M (described above) of a polyparahydroxystyrene resin and 6.6 parts of an epoxy resin having a benzophenone-based imide group were dissolved and reacted in 117 parts of butyl carbitol acetate at 100 ° C. for 1 hour to obtain a viscosity. A thick resin was obtained. A conductive paste was prepared by mixing 22 parts of this resin with 1.0 part of an amine complex of boron trifluoride as a catalyst, 57 parts of silver powder, 2.0 parts of AERYL # 200 (described above), and 50 parts of butyl acetate.

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 was dipped therein to form a cathode layer, and then the lead frame and the cathode layer were joined, and a resin was formed by a molding method. To produce a solid electrolytic capacitor. The solid electrolytic capacitor thus obtained was tested for adhesion strength and moisture current leakage. The results are shown in Table 1, and all of them show that the present invention is excellent, and the effect of the present invention was confirmed.

[Effects of the Invention] As is clear from the above description and Table 1, the solid electrolytic capacitor of the present invention is excellent in adhesiveness and electrical properties after moisture resistance, and the electrical properties are not deteriorated even when packaged with a resin. It 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 modified resin composed of a styrene resin and an epoxy resin, (B) an epoxy resin having a benzophenone-based imide group, (C) a conductive powder and a fine silica-based powder, and (D) a conductive paste containing an acetate-based solvent as an essential component. A solid electrolytic capacitor characterized by being formed.