JPH0770416B2 - Method of manufacturing chip type film capacitor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a chip type film capacitor.

2. Description of the Related Art In recent years, electronic devices have become more and more multifunctional and more compact, and electronic parts used for them have become smaller, lighter, shorter and smaller. A typical example is chip formation of electronic components.

Among the chip capacitors, the chip film capacitors are currently larger in volume and projected area than chip tantalum electrolytic capacitors and chip ceramic capacitors. That is, the chip-type film capacitor is formed by winding a metallized plastic film pair having a thickness of 1 to 3 μm around a circular drum having a diameter of 600 mm for several hundred times, and then for a few hundred times over it through a spacer, and repeating this. After forming multiple layers and applying metallikon to both end surfaces, heat-treating and precut into semi-circular shape, then cutting to a predetermined size, welding the lead frame to the metallikon part to suit the surface mounting method, shape, In order to improve the dimensional accuracy, we manufacture chip-type film capacitors by performing molding such as transfer molding (injection molding) as an exterior method.

Problems to be Solved by the Invention However, in molding such as transfer molding, the outer thickness is required to be 0.5 mm or more, and even if the dielectric film is thickened, the outer thickness ratio becomes large, which is larger than other chip type capacitors. This is an obstacle to downsizing, and the amount of capital investment for welding machines and molding machines for welding external extraction electrodes such as lead frames is high. There were drawbacks such as a significant decrease in the amount of stay and an increase in cost.

Means for Solving the Problems The present invention is intended to provide a method for manufacturing a chip-type film capacitor which eliminates the above-mentioned drawbacks, and is manufactured by the following process sequence.

(A) A step of winding a pair of metallized plastic films around the circular drum 1 a predetermined number of times to form a plurality of layers of the wound material 7 through the spacers 2a, 2b, 2c, 2d, and (b) the winding. In the process, before or after inserting the spacer, the adhesive sheet 5 having the strip-shaped electrode foils 4 attached to both end surfaces of the heat-resistant adhesive film 3 is attached to the electrode foils 4 by the spacers 2a, 2
Wind one or more times so that it touches b, 2c, 2d,
A step of providing the electrode layer 6 in advance; and (c) a step of spraying a metal material on both end surfaces of the plurality of layers of the wound material 7 provided with the electrode layer 6 to form the electrode extraction metallikon portion 8. ) A step of heat-treating the plurality of layers of the wound material 7 at a predetermined temperature, (e) a step of preliminarily cutting the plurality of layers of the wound material 7 into a plurality of pieces, and (f) the electrode extraction metallikon portion. 8 is impregnated with a low-viscosity liquid thermosetting resin and is subjected to a thermosetting treatment, (g) a step of polishing the end face of the electrode extraction metallikon part 8, and (h) the electrode extraction metallikon part 8 and the electrode layer 6. This is a method for manufacturing a chip-type film capacitor, which includes a plating step and (i) a cutting step for forming a capacitor 10 having a predetermined electrostatic capacity.

The chip-type film capacitor obtained by the above-described manufacturing method has the electrode foil 4 in the winding step in order to reduce the thickness of the outer package.
The electrode foil 4 is covered with a heat-resistant adhesive sheet 5 attached to
The surface area of the extraction electrode is made sufficiently large by the electrode layer 6 formed in 1. to ensure solderability at the time of mounting on the board, and the slight thickness of the electrode layer 6 is used to form a gap between the board and the capacitor body. It is possible to reduce the influence of heat when mounting and soldering when mounted on a board.

Furthermore, in order to improve the moisture resistance of the above-mentioned capacitor element, a sufficient moisture-proof treatment can be performed by impregnating a low-viscosity liquid thermosetting resin having a viscosity of 200 to 400 cps and a low surface tension of 20 to 30 dynes, thereby improving the moisture resistance. It is possible to obtain a very good chip type film capacitor. Further, the capacitor having the above structure does not require an injection molding machine or an expensive metal mold like a mold type exterior, and only needs a thermosetting furnace for resin curing and a cutting machine, which simplifies the process and reduces the cost. realizable.

EXAMPLE An example of the method of manufacturing the chip film capacitor of the present invention will be described below.

As shown in FIG. 2, a circular drum 1 having a diameter of 600 mm is used as a winding core, and a predetermined number of 25 μm-thick polyethylene terephthalate film is wound around the core to form a spacer 2a. As shown in FIG. A copper foil sticking adhesive sheet 5 in which a strip-shaped copper foil 4 having a thickness of 18 μm and a width of 1 mm is stuck to both end faces of a 16 μm-thick aramid resin film 3 once with the copper foil part 4 inside (in contact with the spacer 2a) The electrode layer 6 is wound to form an electrode layer 6, and a metallized polyethylene terephthalate film (hereinafter referred to as MPET film) or metal polyphenylene fluid film (hereinafter referred to as MPET film) having a thickness of 1.5 to 3 μm and having aluminum as a vapor deposition electrode is formed on the outer periphery of the electrode layer 6. MPPS
A film) is polymerized in a pair and wound 500 times, and the copper foil-bonded adhesive sheet 5 is wound around the outer circumference once with the copper foil portion 4 facing outward to form an electrode layer 6 to form a first layer wound product. 7a is formed, the spacer 2b is formed on the outer periphery of the first layer wound product 7a in the same manner as described above, and the copper foil sticking adhesive sheet 5 is placed on the outer periphery of the spacer 2b in the same manner as described above with the copper foil portion 4 inside. The electrode layer 6 is wound once to form the electrode layer 6, and a pair of MPET film or MPPS film is polymerized on the outer periphery of the electrode layer 6 in the same manner as described above to obtain the same capacitance as that of the first layer wound product 7a. As described above, for example, 494 windings are performed, and the copper foil-bonded adhesive sheet 5 is wound around the outer periphery once to form an electrode layer 6 to form a second layer winding 7b. A spacer 2c is formed on the outer periphery of the wound material 7b in the same manner as above, and a copper foil is attached to the outer periphery of this spacer 2c in the same manner as above. With the adhesive sheet 5 inside, the electrode layer 6 is wound once to form an electrode layer 6, and a pair of MPET film or MPPS film is polymerized on the outer periphery of the electrode layer 6 in the same manner as described above to form the first layer wound product 7a. It is wound, for example, 488 times so as to obtain a capacitance, and is wound once with the copper foil-attached adhesive sheet 5 on the outer side to form an electrode layer 6 to form a third layer wound article 7c. , This 3rd layer roll 7c
The same spacers 2d as described above are formed on the outer circumference of the three-layer wound product 7. Then, zinc or zinc and solder are sprayed on both end faces of the three-layer wound article 7 to form electrode lead-out metallikon portions 8 having a thickness of 0.3 to 0.5 mm. After that, about 180 ℃ (170-23
Heat treatment is performed at a temperature of 0 ° C. for about 2 hours (may be 1 to 3 hours), and after the heat treatment is completed, the three-layer wound product 7 is removed from the circular drum 1 and, as shown in FIG. The semicircular three-layer wound product 7 is cut into two semicircular pieces, and then the semicircular three-layer wound article 7 is cut into two semicircular layers 7a, 7b, 7c.
The layered products 7a, 7b, 7c separated into layers (Fig. 5 shows a cross-sectional view) have a viscosity of 20% in order to improve the moisture resistance.
0 ~ 400cps, low surface tension 20 ~ 30 dynes, glass transition point 100
Low-viscosity liquid epoxy resin of ~ 150 ℃ is vacuum 10 ~ 30mmHg
And impregnation for 3 minutes, followed by heating at 135 ° C. for 2 hours to cure. Since the end face of the electrode lead-out metallikon part 8 is a rough surface and has fine holes, the epoxy resin cured by the impregnation / thermosetting treatment is attached, so that the electrode lead-out is performed as shown in FIG. 6 (cross-sectional view). The end face of the metallikon portion 8 is polished to smooth and remove the resin attached to the end face, and then the copper foil portion 4 and the electrode lead-out metallikon portion 8 are plated with solder 9. After the solder plating, for example, a plurality of chip type film capacitors 10 having a predetermined electrostatic capacity shown in FIG.

Although the MPET film or the MPPS film is used in the above-mentioned embodiments, other metal plastic films may be used, and a three-layer wound product is shown, but a wound product having four or more layers may also be used. Good.

Although the araside resin film is used for the copper foil-bonded adhesive sheet in the above-described embodiments, a film such as a polyimide film, a polyphenylene flu film, a polyethylene terephthalate film, or a U polymer film may be used. The copper foil attached to the adhesive sheet may be a rolled copper foil, an untreated copper foil, an electrolytic copper foil, or the like, and a metal foil such as a nickel foil, an aluminum foil, or a tin foil may be used as an electrode foil in addition to the copper foil.

Although the epoxy resin is used in the above-described embodiments, a thermosetting resin such as a polyester resin or a urethane resin may be used.

Although the circular drum is used in the above-described embodiment, the shape of the drum is not limited to the circular shape.

EFFECTS OF THE INVENTION As described above, in the method for manufacturing the chip-type film capacitor of the present invention, (A) the electrode foil sticking adhesive sheet exterior method is adopted, and the adhesive sheet having an exterior thickness of 0.1 mm or less is used. It can be made smaller than chip-type film capacitors made by molding.

(B) Since the lead frame is not used, a molding machine and a welding machine are unnecessary, and the capital investment amount can be significantly reduced.

(C) Since the surface area of the extraction electrode is made sufficiently large by the electrode layer 6 formed by the electrode foil 4 and the heat-resistant adhesive sheet 5 to which the electrode foil is attached in the winding step, the surface area of the extraction electrode is sufficiently increased. It is possible to ensure the solderability of
Due to the slight thickness of the electrode layer 6, a slight gap is formed between the printed circuit board and the capacitor body, so that direct heat conduction to the capacitor body during soldering is avoided, and thermal damage during soldering is mitigated. Alternatively, it can be avoided, and the deterioration of the electrical characteristics of the capacitor can be prevented.

(D) The dimensional accuracy can be made comparable to that of the conventional molding method.

(E) The capacitor element can be impregnated with a low-viscosity liquid thermosetting resin in order to improve the moisture resistance, and sufficient moisture-proof measures can be taken to obtain a chip-type film capacitor with extremely good moisture resistance.

(F) Capacitor production cost is low and economical.

It is effective in industrial and practical value.

[Brief description of drawings]

1 to 6 show the manufacturing process of the chip type film capacitor of the present invention, FIG. 1 is a perspective view of the finished product, and FIG. 2 is a cross-sectional view of the main part of a three-layer winding product wound on a circular drum. Fig. 3 is a perspective view of the copper foil adhesive sheet, and Fig. 4 is a semicircular shape.
A front view of the divided three-layer wound product, FIG. 5 is a cross-sectional view of the wound product for each layer with electrode drawing metallikon on both end faces, and FIG. 6 is solder plating of the electrode drawing metallikon part and copper foil part. FIG. 3 is a cross-sectional view of the wound material per one layer. 1: Circular drum 2a, 2b, 2c, 2d: Spacer 3: Heat-resistant adhesive film (aramid resin film), 4: Electrode foil (copper foil) 5: Adhesive sheet with electrode foil attached (copper foil adhesive sheet), 6: Electrode layer 7: Multiple layer wound material, 7a: First layer wound material 7b: Second layer wound material, 7c: Third layer wound material 8: Electrode extraction metallikon part, 9: Solder plating 10 : Chip type film capacitor

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Fumio Nishimura Inventor Fumio Nishimura Oike-dori, Nakagyo-ku, Kyoto 1st line Karasuma Higashiiri 1st floor, 4th Uehara Bldg., 191, Nakaboricho Uchihara Bldg. Nichicon Corporation Examiner Shozo Furudera (56) References JP-A-58-199517 (JP, A) Actually-laid-open Sho 63-12823 (JP, U)

Claims (1)

[Claims] 1. A pair of metallized plastic films are wound around a circular drum (1) a predetermined number of times to form spacers (2a, 2b, 2).
c, 2d) to form a plurality of layers of the wound product (7), and strip-shaped electrode foil (4) on both end faces of the heat-resistant adhesive film (3) before or after spacer insertion in the winding process. ) Is attached to the spacer (2a, 2b, 2c, 2d) so that the electrode foil (4) is in contact with the spacer (2a, 2b, 2c, 2d), and the electrode layer (6) is provided in advance, The multi-layer wound article (7) including the electrode layer (6)
A step of thermally spraying a metal material on both end surfaces of the electrode to form an electrode extraction metallikon part (8), a step of heat-treating the multi-layer wound material (7) at a predetermined temperature, and a step of heat-treating the multi-layer winding after the heat treatment. A step of preliminarily cutting the revolving metal (7) into a plurality of pieces; a step of impregnating and thermosetting the electrode lead-out metallikon portion (8) with a low-viscosity liquid thermosetting resin; A chip-type film capacitor including a step of polishing an end face, a step of plating the electrode extraction metallikon part (8) and an electrode layer (6), and a cutting step of forming a capacitor (10) having a predetermined capacitance. Production method.