JPH0437019A - A solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prepare a solid electrolytic capacitor with superior electrical characteristics after moisture-proofing despite resin armoured capacitor by forming a dielectric layer, semiconductor layer, and negative electrode layer sequentially on the positive electrode made of metal having a valve action, while in the resin armoured solid electrolytic capacitor by forming the negative electrode using conductive paste consisting of particular resin, powder, and solvent. CONSTITUTION:When the negative layer of a solid electrolytic capacitor is formed using a modified resin made of polyparahydroxystyrene resin and epoxy resin, conductive powder and fine silica powder, and aliphatic hydrocarbons solvent as prerequisite components, the negative layer is formed to have a superior adhesiveness, thus being able to prepare a solid electrolytic capacitor whose electrical characteristics after moisture-profing are not easily degraded.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to a solid electrolytic capacitor that is packaged with resin and has excellent electrical characteristics.

(Prior Art) As shown in FIG. 1, a solid electrolytic capacitor related to the present invention has a dielectric layer 2 formed by chemically treating an anode body 1 made of a metal with a valve action such as tantalum, aluminum, or niobium.
After forming, a semiconductor layer 3 and a cathode layer 4 are further formed on the surface.
At the same time, the cathode layer 4 is adhesively fixed to the external lead frame 5 using a conductive adhesive 6, and the anode body lead 7 leading to the anode body 1 is joined to the anode external lead 8 with solder 9. The outer peripheral surface is covered with a covering resin 10.

(Problem to be Solved by the Invention) However, conventionally, the cathode layer is formed using an ordinary conductive paste, and the electrical properties of the solid electrolytic capacitor after moisture resistance deteriorate due to the performance of the conductive paste of the cathode layer. was there.

The present invention has been made to eliminate the above-mentioned drawbacks, and aims to provide a solid electrolytic capacitor that has excellent electrical characteristics after being resistant to moisture despite being coated with resin.

[Means for Solving the Problems of the Invention] As a result of intensive research aimed at achieving the above object, the inventors of the present invention have developed adhesive properties by using Asasei's conductive paste, which will be described later. The inventors have completed the present invention by discovering that a solid electrolytic capacitor can be obtained in which a cathode layer with excellent properties can be formed and whose electrical characteristics are less susceptible to deterioration after being resistant to moisture.

That is, the present invention provides a solid electrolytic capacitor in which a dielectric layer, a semiconductor layer, and a # electrode layer are sequentially formed on an anode body made of a metal having a valve action, and the cathode layer is (A) It is characterized by being formed of a modified resin consisting of polyparahydroxystyrene resin and epoxy resin, (B) conductive powder and aim silica powder, and (C) conductive paste whose essential components are an aliphatic hydrocarbon solvent. This is a solid electrolytic capacitor.

The present invention will be explained in detail below.

For the modified resin (A) consisting of polyparahydroxystyrene resin and epoxy resin used in the present invention, polyparahydroxystyrene resin and epoxy resin may be simply dissolved and mixed, or if necessary, they can be mutually mixed by heating reaction. They may be partially bonded, and a curing catalyst may be used if necessary for the reaction. Furthermore, the working viscosity can be improved by dissolving these component resins in a common solvent.

The polypara-droxystyrene resin used here is a resin represented by the following formula.

(However, in the formula, n represents an integer of 25 to 90.) Examples of such resins include Markarin Riki-M (manufactured by Kokushi Petrochemical Co., Ltd., trade name), which has a molecular weight of 3000 to 800.
0 and the hydroxyl equivalent is about 120. Epoxy resins used in the modified resin include dieboxides of suphenols such as those listed below, which are industrially produced and can be effectively used in the present invention. Epicote 827, 828, 834, 1001, 1002゜1007.1009 (manufactured by Shell Chemical Co., Ltd., trade name), D
ER330, 331, 332, 334, 335°336
．． 337,660 (trade name manufactured by Tau Chemical Company), Araldite GY250,260,2806071.608
4,6097.6099 (Ciba Power manufactured by Iggy Co., Ltd., product name), EPI-REZ510゜5101 (JONE
Manufactured by DABNEY, product name), Epicron 810,10
There are 00,1010°3010 (manufactured by Dainippon Ink and Chemicals Co., Ltd., trade name) and EP series (manufactured by Jiryuka Co., Ltd., trade name).

Further, by using a novolac epoxy resin having an average number of epoxy groups of 3 or more, for example, the adhesive strength at high temperatures (350° C.) can be further improved. As these novolak epoxy resins, those having a molecular weight of 500 or more are suitable. Examples of such novolak epoxy resins that are industrially produced include the following. Araldite BPNI 13'8,1139
, ECN1273.1280.1299 (manufactured by Ciba Geigy, trade name), DEN431,438 <manufactured by Dow Chemical Company, trade name), Epicote 152.154 (manufactured by Shell Chemical Company, trade name), ERR-Of 00, ERRB
-0447, ERLB-0488 (manufactured by Union Carbide Co., Ltd., trade name), EOCN series (manufactured by Nippon Kayaku Co., Ltd., trade name), etc. These epoxy resins can be used alone or in combination of two or more. be able to.

It is preferable to dissolve and mix the modified resin consisting of polyparahydroxystyrene resin and epoxy resin in the following solvents. Solvents that can be used here include dioxane, hexane, benzene, toluene, solvent naphtha, industrial gasoline, and cellosolve 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.

As the conductive powder and fine silica powder (B) used in the present invention, a conductive powder and fine silica powder are used in combination. As the conductive powder, silver powder, silver-plated copper powder, copper powder, nila gel powder, carbon, etc. are used. Further, examples of the fine silica powder include Aeroseal (manufactured by Nippon Aeroseal Co., Ltd., trade name), and those having a particle size of 1 μm or less are preferable.

As the aliphatic hydrocarbon solvent (C) used in the present invention,
It is used as a component of the solvent for the paste, and there are no particular restrictions as long as it is an aliphatic hydrocarbon solvent. Examples of these solvents include gasoline, petroleum, benzene, mineral spirits, hexane, and petroleum naphtha. These can be used alone or in a mixture of two or more.

The conductive paste used in the present invention contains a modified resin consisting of polyparahydroxystyrene resin and epoxy resin, conductive powder, machine cord silica powder, and aliphatic hydrocarbon solvent as essential components. Antifoaming agents and other additives may be added and blended as necessary within a range that does not cause adverse effects.

After thoroughly mixing these components according to a conventional method, the mixture is further kneaded using, for example, three rolls, and then defoamed under reduced pressure and diluted with an acetate-based solvent, and the solid electrolytic capacitor element is dipped to form a cathode layer. After that, after bonding the cathode layer and lead frame with a conductive adhesive, the TII body lead is soldered to the anode external lead, and the exterior is coated with resin using a molding method or dip method to manufacture a solid electrolytic capacitor. can.

(Function) The solid electrolytic capacitor of the present invention has excellent adhesive properties and electrical properties after moisture resistance by using a modified resin consisting of polyparahydroxystyrene resin and epoxy resin, and by using an aliphatic hydrocarbon solvent in particular. I was able to make it work.

(Examples) Next, the present invention will be specifically explained by examples, but the present invention is not limited by these examples.
In the following Examples and Comparative Examples, "parts" means "parts by weight J" unless otherwise specified.

Example 1 37.5 parts of the epoxy resin Epikote 1001 (manufactured by Shell Chemical Co., Ltd., trade name) and 10 parts of the polyparahydroxystyrene resin Marcarin Power-M (manufactured by Koki Petrochemical Co., Ltd., trade name) were mixed with diethylene glycol. A viscous resin was obtained by dissolving and reacting in 103 parts of diethyl ether at 100°C for 1 hour.To 22 parts of this resin, 1.0 part of an amine complex of boron trifluoride as a catalyst and 0.03 part of an additive were added. , 57 parts of silver powder, 2.0 parts of Aeroseal #200 (manufactured by Nippon Aeroseal Co., Ltd., trade name), 5 parts of hexane, and 45 parts of butyl acetate were mixed to produce a conductive paste.

Example 2 15.8 parts of epoxy resin Epikote 828 (manufactured by Shell Chemical Co., Ltd., trade name) and 1 part of polyparahydroxystyrene resin Marcarin Power-M (manufactured by Marumae Petrochemical Co., Ltd., trade name)
0 parts and 10 parts in 56 parts of butyl cellosolve acetate.
A dissolution reaction was carried out at 0° C. for 1 hour to obtain a viscous resin. To 22 parts of this resin, boron trifluoride amine i was added as a catalyst.
M body 1.0 parts, silver powder 57 parts, Aeroseal #200
<previously mentioned) 2.5 parts, hexane 5 parts, and butyl acetate 4 parts
A conductive paste was prepared by mixing 5 parts.

Example 3 66 parts of epoxy resin EOCN103S (manufactured by Nippon Kayaku Co., Ltd., trade name) and 34 parts of polyparahydroxystyrene resin Marcarin Power-M (mentioned above) were mixed at 100°C in 117 parts of butylcarpitol acetate. A viscous resin was obtained by dissolving and reacting for 1 hour. To 22 parts of this resin, 1.0 part of an amine complex of boron trifluoride as a catalyst, 57 parts of silver powder, 2.0 parts of Aerosil #200 (mentioned above), and 5 parts of hexane.
and 45 parts of butyl acetate to prepare a conductive paste.

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

Using the conductive pastes obtained in Examples 1 to 3 and Comparative Examples, a solid electrolytic capacitor was dipped therein to form a cathode layer, and then the lead frame and the cathode layer were bonded and molded. Coated with resin and hardened
Manufactured electrolytic capacitors. The solid electrolytic capacitor thus obtained was tested for adhesive strength and moisture resistance and current leakage.

The results are shown in Table 1, and the present invention was superior in all cases, confirming the effects of the present invention.

[Effects of the Invention] As is clear from the above explanation 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 exteriorized with resin. The deterioration in properties was slight.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view of a solid electrolytic capacitor to which the present invention relates. 1...Anode body, 2...Dielectric layer, 3...Semiconductor layer, 4...# as pole layer, 5...lI! Pole lead frame, 6... Conductive adhesive, 7. Anode body lead, 8... Anode outer lead, 9... Solder,
1o...Exterior resin. Patent ratio - person Toshiba Chemical Corporation *1: 2.0 on lead frame with ffl plating
@X2. Glue the OIm silicone tip and measure using a tension gauge at a temperature of 25°C. 2 Dielectric layer

Claims (1)

[Claims] 1. An anode body made of a metal having a valve action, a dielectric layer,
In a solid electrolytic capacitor in which a semiconductor layer and a cathode layer are sequentially formed and then packaged with a resin, the cathode layer is made of (A) a modified resin made of polyparahydroxystyrene resin and an epoxy resin, (B) conductive powder and fine silica. A solid electrolytic capacitor formed of a conductive paste containing powder and (C) an aliphatic hydrocarbon solvent as an essential component.