JPS6120312A - Method of producing chip type solid electrolytic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an IN manufacturing method for a chip-type solid electrolytic capacitor, particularly to improvements in moisture-proof preparation and lead frame connection means.

[Technical background of the invention and its problems] In general, chip-type solid electrolytic capacitors are manufactured by, for example, embedding and sintering a lB pole wire (21) in a valve metal powder, as shown in FIG. A lead frame (23) is connected to each of the anode wire (21) and the cathode conductive layer constituting the outer surface of the capacitor element (22) of the capacitor element (22) formed through the steps of (24) to form a capacitor body (25), and then the lead frame (23) is attached to both sides (26) of the capacitor body (25).
) and the bottom surface (27). However, the exterior thickness t of a chip-type solid electrolytic capacitor made of 4R is generally 0.3 to 0.5M.
Since the lead frame (23) is extremely thin, attempts have been made to apply an undercoat to improve moisture resistance, but the target object is small and the lead frame (23) is plate-shaped. Since the undercoat was drawn out in the opposite direction, it was difficult to apply the undercoat with high precision. That is, the capacitor element (21
) It is impossible to form an undercoat film by immersing only the part in the undercoat paint solution, and when applying an undercoat, it must be applied by dipping, which may cause problems in workability. Of course, since the undercoat material is in the form of paint, it flows as shown in Figure 7, causing the undercoat film (29) to adhere to unnecessary parts of the lead frame (28) or to an insufficient thickness. There were many problems that needed to be resolved, such as the undercoat material becoming uniform and exposed from the outer H (30) surface, and unnecessary undercoat material adhering to the mold during transfer molding. For this reason, methods have been adopted to improve the moisture resistance of the capacitor element itself by improving the method of forming MnO2, but it is still not perfect and in the end, the capacitor element is packaged without an undercoat in preparation for a certain amount of moisture absorption. This is the current situation. In the figure, (31) is a capacitor element.

[Object of the Invention] The present invention has been made in view of the above points, and by adopting a means for performing an undercoat treatment before connecting the lead frame and removing the undercoat film at the lead frame connection part. It is an object of the present invention to provide a method for manufacturing a chip-type solid electrolytic capacitor that can prevent characteristic deterioration due to moisture absorption and has good workability.

[Summary of the Invention] The method for manufacturing a chip-type solid electrolytic capacitor of the present invention involves immersing a capacitor element formed by integrally embedding an anode wire in valve metal powder and sintering it in a synthetic resin paint, and coating the entire circumference of the capacitor element. Before curing the undercoat film formed on the surface, remove the paint film on the part that will be bonded to the lead frame, then heat and harden the paint film on other parts, and connect the lead frame to the part where the paint film was removed. It is characterized by applying the exterior by transfer molding.

[Embodiments of the Invention] The details of the present invention will be described below with reference to the drawings. That is, as shown in Fig. 2, an anode wire (1) is integrally embedded and sintered in a valve metal powder such as tantalum or aluminum, and then a dielectric oxide film, a solid electrolyte, a carbon graphite layer, and a tin metal layer are formed on the surface of the anode body. The capacitor element (2) is made of, for example, epoxy, which is formed by sequentially forming cathode layers.

Means for dipping into a synthetic resin coating liquid (3) such as urethane, acrylic, silicone, etc. and then pulling it up to form an undercoat film (4) on the entire circumferential surface of the capacitor element (2) as shown in FIG. and means for removing a part of the undercoat film (4) by, for example, air blasting or sandblasting to form a film removed portion (5) as shown in FIG. As shown in FIG.
) are respectively connected to the lead frame (7) which becomes the cathode plate metal terminal to the paint film removed part (5), and an exterior (8) is applied by transfer molding to form the capacitor body (9), and the capacitor body (9) is led out from the capacitor body (9). It consists of a means for bending a lead frame (61 (7)) along the capacitor main body (9), side surface (10) and bottom surface (11).Identical parts in FIGS. 1 to 4 are the same. A code is attached.

According to the deep-type solid electrolytic capacitor constructed as described above, the undercoat treatment is performed on the lead frame (6) (
7) Since it is immersed in the synthetic resin paint liquid (3) before connection, the synthetic resin paint does not adhere to the lead frame (6H7) and only the capacitor element (2) is coated with a uniformly thick undercoat film ( 4) The viscosity of the synthetic resin coating liquid (3) can be lowered due to immersion, making it possible to form a 1JIll coating film, efficiently preventing characteristic deterioration due to moisture absorption, and preventing chip-type coating using conventional means. Problems with the manufacturing method of solid electrolytic capacitors can be solved at once.

In the above embodiment, the case where one capacitor element is immersed alone in the synthetic resin paint liquid will be exemplified and explained in 1. As shown in FIG.
) A plurality of anode wires (14) are connected together, for example, by a connecting body (15).
) to support multiple pieces at once and apply synthetic resin coating liquid (16
), it goes without saying that the undercoat treatment may also be carried out by immersing it in a liquid.

Next, the conditions of the chip-type solid tantalum capacitor obtained according to Example (A) of the present invention and the chip-type solid tantalum capacitor obtained according to the conventional reference example (8) without undercoating at 121°C and 2 atm. The volume change rate and ta with respect to time in the pressure cutter burst by
As a result of investigating changes in nδ characteristics, the results were as shown in FIGS. 8 and 9. In Example (A), the sample b was immersed in a silicone resin paint solution as an undercoat treatment, so the samples were 30 for each of 6V-15 μF (A) and (B), and the numerical value is an average value. As is clear from FIGS. 8 and 9, the rate of change in customer numbers and tan δ both increase with the passage of time in the case of Reference Example (8), whereas in the case of Example (A
) demonstrated an excellent effect with a small rate of change.

[Effects of the Invention] According to the present invention, a capacitor element formed by integrally embedding and sintering an anode wire is immersed in a synthetic resin paint, an undercoat film is formed on the entire circumference of the capacitor element, and the paint film is The paint film on the part that will be bonded to the lead frame is removed before curing, and then the lead frame is connected to the part where the paint film is removed after it hardens, which prevents property deterioration due to moisture absorption and improves workability. A method for manufacturing a chip-type solid electrolytic capacitor can be provided.

[Brief explanation of drawings]

Figures 1 to 4 relate to one embodiment of the present invention; Figure 1 is a sectional view showing a completed chip-type solid electrolytic capacitor;
The figure is a schematic diagram explaining the means for applying undercoat 1, Figure 3 is a sectional view showing the capacitor element after forming the undercoat film, and Figure 4 is the capacitor element after forming the removed part of the undercoat film. FIG. 5 is a schematic diagram illustrating an undercoat means according to another embodiment, and FIGS. 6 and 7 are sectional diagrams each showing a completed chip type solid electrolytic capacitor according to a conventional reference example. be. (11 (14)... Anode wire (2) (13)... Capacitor element (31 (1
6)...Synthetic resin coating liquid (4)...
・・・・・・Undercoat film (5)・・・・・・・・・
...... Paint film removal part (6) (7) ...... Lead frame (8) ...... Exterior (
9)・・・・・・・・・Capacitor body (10)
・・・・・・・・・・・・Side (11)・・・・・・
・・・・・・Applicant for permission to hold the bottom side Marukon Electronics Co., Ltd. Figure 2 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Simple side (appetizer) Figure 9 Procedure Amendment Writing Method) % Formula % 1. Indication of the case 1982 Patent Group No. 1141064 2. Title of the invention Method for manufacturing chip-type solid electrolytic capacitors 3. Person making the amendment Relationship to the case Patent applicant Address: 1560 Miya, Nagai City, Yamagata Prefecture Telephone: Nagai (0238184-2131 (main)) Postal code: 993 October 30, 1980 (shipment date) 5. Subject to correction nn 411116 M 1m W M mi IM
6! a 11 The figure shows one embodiment of the present invention, and FIG. 1 is a sectional view showing a completed chip-type solid electrolytic capacitor.
Fig. 2 is a schematic diagram explaining the undercoat means, Fig. 3 is a sectional view showing the capacitor element after forming the undercoat film, and Fig. 4 shows the capacitor element after forming the removed portion of the undercoat film. 5 is an original schematic diagram illustrating an undercoat means according to another embodiment, and FIGS. 6 and 7 are sectional views each showing a completed chip type solid electrolytic capacitor according to a conventional reference example, Figure 8 shows time-
FIG. 9 is a capacitance change rate characteristic curve diagram, and FIG. 9 is a time-loss characteristic curve diagram.

Claims (1)

[Claims] A means for forming a capacitor element by integrally embedding an anode wire in valve action metal powder and sintering it; a means for immersing and pulling up the capacitor element in a synthetic resin paint solution to form an undercoat film; A means for removing a part of the film by air blasting or sandblasting to form a film-removed part, a means for subsequently heating to harden the undercoat film, and a lead frame for each of the anode wire and the film-removed part. a means for connecting the capacitor, and a means for packaging the capacitor with transfer molding to form a capacitor body;
A method for manufacturing a chip-type solid electrolytic capacitor, comprising sequentially bending each lead frame led out from the capacitor body along the side and bottom surfaces of the capacitor body.