JPH04209514A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent that the bonding property of a cathode electrode to a semiconductor layer and to an outer-package resin, the moistureproof property of a capacitor and the electric characteristic of the capacitor after a moistureproof treatment are deteriorated by a method wherein a one-liquid conductive paste whose composition is specific is used. CONSTITUTION:At a solid electrolytic capacitor, a dielectric layer 2, a semiconductor layer 3 and a cathode electrode 4 are formed sequentially on an anode body 1 composed of a metal provided with a valve action. It is outer-packaged by using a resin. At the solid electrolytic capacitor, the electrode 4 is formed of a conductive paste whose essential components are a denatured resin, a conductive powder, a fine silica powder, a porous filler and a water repellent. The denatured resin is composed of polypara-hydroxy styrene and an epoxy resin; a silver powder, a silver-plated copper powder, a copper powder, a nickel powder, carbon or the like is used as the conductive powder. The manufactured conductive paste is diluted additionally with butyl acetate; a solid electrolytic capacitor element is dipped; the cathode electrode is formed. Thereby, the bonding property and the electric characteristic of the solid electrolytic capacitor are enhanced, the electric characteristic is not lowered even after a moistureproof treatment and the reliability of the capacitor can be enhanced.

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor with excellent adhesive properties and electrical properties. [0002]

[Prior Art] Conventionally, this type of solid electrolytic capacitor is
As shown in FIG. 1, an anode body 1 made of a metal with valve action such as tantalum, aluminum, niobium, etc. is subjected to chemical conversion treatment,
After forming the dielectric layer 2, a semiconductor layer 3 and a cathode electrode 4 are sequentially formed on its surface, and the cathode electrode 4 is bonded to the cathode lead frame 5 using a conductive adhesive 6, and the anode body 7 is soldered. 8, and its outer peripheral surface is bonded to resin 9.
It is made up of an exterior. [0003] However, in the past, the cathode electrode was usually formed using a conductive paste, and there was a drawback that the electrical characteristics of the solid electrolytic capacitor after a moisture resistance test deteriorated due to the performance of the semiconductor paste of the cathode electrode. [0004]

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a solid electrolytic capacitor that has excellent adhesive properties and negative characteristics at the cathode electrode. [0005]

[Means for Solving the Problems] As a result of intensive research to achieve the above object, the present inventors have found that by forming a cathode electrode using a one-component conductive paste having the composition described below. The present invention has been completed by discovering that the above object can be achieved. [0006] That is, the present invention provides a solid electrolytic capacitor in which a dielectric layer, a semiconductor layer, and a cathode electrode are sequentially formed on an anode body made of a metal having a valve action, and the solid electrolytic capacitor is packaged with a resin. ) a modified resin consisting of polyparahydroxystyrene and (b) an epoxy resin. (B) conductive powder (C) fine silica powder (D) porous filler (E) solid electrolyte characterized by forming a cathode @ electrode using a conductive paste containing a water repellent as an essential component It is a capacitor. [00071 Modified resin (A) used in the present invention includes:
It consists of (a,) polyparahydroxystyrene and (b) an epoxy resin. (a) Polyparahydroxystyrene is a resin represented by chemical formula 1, and has a molecular weight of 30
00 to 8,000 and a hydroxyl equivalent of about 120. [0008]

[0009] Specific examples thereof include Markarin-Ryoku-M (manufactured by Maruzen Petrochemical Co., Ltd., trade name). [00101(b) Epoxy resins are not limited, but include those that are industrially produced and can be effectively used in the present invention, such as Epicote 827, 828, 83.
4.1001.10O2, 1007, 1009 (manufactured by Shell Chemical Co., Ltd., trade name) DER330, 331, 332, 3
34,335,336,337,660 (manufactured by Dow Chemical Company, trade name), Araldite GY250,260,2
80.6071, 6084, 6097.6099 (manufactured by Ciba Geigy, trade name), EPI-REZ510.5
101 (manufactured by Jonedabney Co., Ltd., trade name), Evicron 810.1000, 1010.3010 (manufactured by Dainippon Ink & Chemicals Co., Ltd., trade name), and EP series (manufactured by Asahi Denka Co., Ltd., trade name). As the epoxy resin, especially when using an epoxy resin having an average number of epoxy groups of 3 or more, such as a novolac epoxy resin, it is possible to
) can further improve the adhesive strength. As these novolac epoxy resins, those having a molecular weight of 500 or more are suitable. Examples of industrially produced novolac epoxy resins include Araldite EPN1.
138,1139,ECN1273,1280.129
9 (manufactured by Ciba Geigy, product name), DEN431,4
38 (manufactured by Dow Chemical Company, trade name) Ebiko h152
, 154 (manufactured by Shell Chemical Co., Ltd., trade name), ERR-01
00, ERRB-0447, ERLB-0488 (manufactured by Union Carbide Co., Ltd., trade name), EOCN series (manufactured by Nippon Kayaku Co., Ltd., trade name), etc., and these can be used alone or in a mixture of two or more types. can. [00111 The modified resin used in the present invention may be obtained by simply dissolving and mixing polyparahydroxystyrene and an epoxy resin, or may be obtained by partially bonding them together by heating reaction, if necessary. When carrying out the reaction, a curing catalyst can be used if necessary. [0012] In the case of dissolving and mixing, polyparahydroxystyrene and epoxy resin may be added and dissolved at once, but first, polyparahydroxystyrene is dissolved in a solvent,
Next, it is preferable to dissolve and mix the epoxy resin. The working viscosity can also be improved by dissolving these component resins in a common solvent. Solvents used here include dioxane, hexane, benzene, toluene,
Solvent naphtha, industrial gasoline, cellosolve acetate,
Examples include butyl acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carpitol acetate, diethylene glycol diethyl ether, dimethyl formamide, dimethyl acetamide, N-methyl pyrrolidone, etc., and these may be used alone or in combination of two or more. [0013] Examples of the conductive powder (B) used in the present invention include silver powder, silver-plated copper powder, copper powder, nickel powder, carbon, etc., and these can be used alone or in a mixture of two or more kinds. . [0014] Examples of the fine silica powder (C) used in the present invention include Aeroseal (manufactured by Nippon Aeroseal Co., Ltd., trade name) with an average particle size of 1 μm or less, and these may be used alone or in combination of two or more. can be used. [0015] Examples of the porous filler (D) used in the present invention include talcite, Ketschenblack, and celite, and these can be used alone or in combination of two or more. [0016] The water repellent (E) used in the present invention includes fluorocarbon-based, silicone-based, etc.
Examples include TL450, 610, 500F, KT400M (manufactured by Kitamura Co., Ltd., trade name), TSL8241.81.85 (manufactured by Toshiba Silicone Co., Ltd., trade name), and these can be used alone or in a mixture of two or more kinds. can. [0017] The conductive paste used in the present invention has as essential components a modified resin consisting of polyparahydroxystyrene and an epoxy resin, a conductive powder, a fine silica powder, a porous filler, and a water repellent. Antifoaming agents and other additives may be added and blended as necessary within a range that does not cause adverse effects. After thoroughly mixing the above-mentioned components according to a conventional method, the mixture is further kneaded using three rolls, and then defoamed under reduced pressure to produce a conductive paste. [0018] The conductive paste thus produced is further diluted with butyl acetate, and a solid electrolytic capacitor element is dipped to form a cathode electrode. Thereafter, after bonding the cathode electrode and the lead frame with a conductive adhesive, the anode body lead is soldered, and the exterior is coated with a resin by a molding method or a dip method to manufacture a solid electrolytic capacitor. [0019]

[Function] The solid electrolytic capacitor of the present invention uses a one-component conductive paste having the composition described above, thereby improving the adhesion of the cathode electrode to the semiconductor layer and the exterior resin, the moisture resistance of the capacitor, and the electrical properties after moisture resistance. was able to prevent deterioration. [00201

[Examples] Next, the present invention will be specifically explained by examples, but the present invention is not limited by these examples. In addition, in the following examples and comparative examples, “
"Parts" means "parts by weight" unless otherwise specified. [00211 Example 1 37.5 parts of epoxy resin Epikote 1001 (manufactured by Shell Chemical Co., Ltd., trade name) and 10 parts of parahydroxystyrene Marukalinker M (manufactured by Maruzen Petrochemical Co., Ltd., trade name) were mixed with diethylene glycol diethyl ether. A dissolution reaction was carried out in 103 parts at 100° C. for 1 hour to obtain a viscous modified resin. To 22 parts of this resin, 1.0 part of boron trifluoride amine complex as a catalyst, 0.03 part of additive, 57 parts of silver powder,
Fine silica powder: 2.0 parts of Aeroseal #200 (manufactured by Nippon Aeroseal Co., Ltd., trade name), 0.1 part of Talcite
A conductive paste was prepared by mixing 0.5 parts of KTL-500F (manufactured by Kitamura Co., Ltd., trade name) as a water repellent, and 50 parts of butyl acetate. [0022] Example 2 Epoxy resin Epicoat 828 (manufactured by Shell Chemical Co., Ltd.,
05.8 parts of the product name and 10 parts of parahydroxystyrene marcarine force-M (manufactured by Maruzen Petrochemical Co., Ltd., trade name),
100°C in 56 parts of butyl cellosolve acetate, 1
A time dissolution reaction was performed to obtain a viscous modified resin. To 22 parts of this resin, 1.0% of an amine complex of boron trifluoride was added as a catalyst.
0 parts, 57 parts of silver powder, 2.5 parts of Aeroseal #200 (mentioned above) as fine silica powder, 0.1 part of talcite,
KTL6100 (manufactured by Kitamura Co., Ltd., trade name) 5 as a water repellent
and 50 parts of butyl acetate were mixed to prepare a conductive paste. [0023] Example 3 66 parts of epoxy resin EOCN103S (manufactured by Nippon Koyaku Co., Ltd., trade name) and 34 parts of parahydroxystyrene Marcalin Power-M (mentioned above) were heated at 100°C in 117 parts of butylcarpitol acetate. , conduct a dissolution reaction for 1 hour,
A viscous modified resin was obtained. To 22 parts of this resin, 1.0 part of an amine complex of boron trifluoride as a catalyst, 57 parts of silver powder,
Aeroseal #200 as fine silica powder (mentioned above)
2.0 parts, 0.1 parts of talcite, TSL8 as water repellent
241 (manufactured by Toshiba Silicone Co., Ltd., trade name) and 50 parts of butyl acetate were mixed to prepare a conductive paste. [0024] Comparative Example A commercially available epoxy resin-based solvent-based conductive paste for semiconductors was obtained. [0025] After dipping the solid electrolytic capacitor element with the conductive paste obtained in Examples 1 to 3 and the comparative example to form a cathode electrode, the lead frame and the cathode electrode were joined, and the conductive pastes obtained in Examples 1 to 3 and Comparative Example were dipped, and then the lead frame and the cathode electrode were bonded, and the conductive pastes were molded with resin. A solid electrolytic capacitor was manufactured by applying an outer coating. [0026] Adhesion and moisture absorption current leak tests were conducted on the obtained conductive paste or solid electrolytic capacitor, and the results are shown in Table 1. The present invention exhibits excellent characteristics*
*The effect of the present invention could be confirmed. [0027] [Table 1] *: 2.0mmX on a silver-plated lead frame
A 2.0 mm silicon chip was bonded at 200°C for 60 minutes, and the temperature was measured at 25°C using a tension gauge. [0028]

[Effects of the Invention] As is clear from the above explanation and Table 1, the solid electrolytic capacitor of the present invention has excellent adhesive properties and electrical properties, and the electrical properties do not deteriorate even after moisture resistance, making it highly reliable. Met.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of a solid electrolytic capacitor to which the present invention relates.

[Explanation of symbols]

1 Anode body 2 Dielectric layer 3 Semiconductor layer 4 Cathode electrode 5 Cathode lead frame 6 Conductive adhesive 7 Anode body lead 8 Solder 9 Exterior resin

Claims (1)

[Claims] [Claim 1] A solid electrolytic capacitor in which a dielectric layer, a semiconductor layer, and a cathode electrode are sequentially formed on an anode body made of a metal having a valve action, and the solid electrolytic capacitor is covered with a resin, comprising: (A) polyparahydroxystyrene and epoxy; A cathode electrode is formed using a modified resin (B) conductive powder (C) fine silica powder (D) porous filler (E) a conductive paste whose essential ingredients are a water repellent. solid electrolytic capacitor.