JP2870179B2 - Chip type metallized film capacitor and manufacturing method thereof - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel metallized film capacitor, and particularly to a chip-type metallized film capacitor suitable for surface mounting, which requires heat resistance and miniaturization, and its manufacture. About the method.

2. Description of the Related Art In recent years, there has been a strong demand for electronic and electric components to be smaller, lighter, have higher performance, have lower costs, and be compatible with surface mounting.
There is no exception in film capacitors, and research and development are being actively conducted for miniaturization and high performance.

6 (a) and 6 (b) show the structure of a conventional metallized film capacitor. As shown in the figure, a metallized film composed of a vapor-deposited electrode layer 17 formed by vapor-depositing a metal on one side of a derivative film 16 composed of a plastic film is laminated, and cut to an appropriate size. End electrodes 13 are formed by spraying metal. The surface of the end face electrode 13 is covered with solder to form a solder plated electrode 14. Further, the side surface of the capacitor element is covered with a simple protective film to complete the capacitor element. 19 is a margin.

An effective method for making a film capacitor into chips and miniaturizing it to be compatible with surface mounting is to construct a capacitor element using a metallized film obtained by depositing a metal material on a heat-resistant dielectric film that is as thin as possible. And to reduce the parts that are not directly related to the capacitor capacity as much as possible.
That is, it is necessary to make the exterior as simple as possible.

At present, a moldless chip type capacitor shown in FIG. 2 can be cited as one of the most miniaturized configurations among the film capacitors for surface mounting. This is a configuration in which the exterior formed by a conventional film capacitor molding method is almost removed, and has a configuration in which an extremely thin protective film having a thickness of about 0.1 mm is coated on the outside of the capacitor element. The exterior of the conventional film capacitor is
In particular, it is not unusual to have a thickness of several mm in order to impart solder heat resistance, such as in the case of surface mounting, and this moldless chip capacitor is an epoch-making miniaturized product.
This moldless chip type capacitor can obtain solder heat resistance for surface mounting only with a simple protective film because the dielectric film used is a polyphenylene sulfide (PPS) film or polyethylene naphthalate. (Hereinafter abbreviated as PEN) due to the use of plastic film with excellent heat resistance such as film.
However, simply using these heat-resistant plastic films cannot be used as a moldless chip type capacitor. Even if the plastic film itself has solder heat resistance, the heat-shrinkable phenomenon always occurs in the heat-resistant plastic film manufactured through the stretching step. For example, when a capacitor element made of a heat-resistant plastic film is put into a solder bath at about 220 ° C. to 230 ° C., large deformation of the capacitor element occurs due to thermal shrinkage of the film. In order to prevent this deformation, thermal aging of the capacitor element is indispensable. That is,
After laminating or winding a metallized film and forming end face electrodes on both side surfaces, in order to impart solder heat resistance, at least under an atmosphere of about 200 ° C. or more, apply appropriate pressure to the capacitor element, Means for performing a heat aging treatment is taken.

The problem to be solved by the present invention By applying such a conventional high-temperature heat aging treatment to a plastic film, the adhesive strength between the film layers is extremely enhanced. Recovery effect (self-healing) is not sufficiently exhibited. This self-healing action is, as shown in FIGS. 7 (a) to (c), (a) →
The process proceeds in the order of (b) → (c).
In order to sufficiently exhibit this effect, a minimum amount of oxygen necessary for oxidizing the deposition electrode and the dielectric and a minimum space necessary for scattering generated gas and products are required. When the adhesive strength between the film layers of the capacitor element is extremely enhanced, the self-healing effect is less likely to be exerted due to a lack of space for scattering oxygen and reaction products required for oxidation. A general film capacitor having a self-healing action does not break down as a capacitor due to the above-mentioned self-healing action, even if it contains some film defect.
On the other hand, in a moldless chip type capacitor in which the interlayer adhesive strength is extremely enhanced by the heat treatment, even if the same voltage is applied to the capacitor, the capacitor is easily broken.

Actually, compared to metallized film capacitors that have a self-healing effect, the potential gradient of the moldless chip type capacitor (rated voltage value applicable per unit thickness of dielectric)
Has a value of about 1/2.

At present, there is a demand for further miniaturization of chip components for surface mounting. In order to meet such demands, improvement of the potential gradient is an unavoidable subject.

In addition, high reliability for film capacitors has become an indispensable requirement today, and in order to meet this requirement, it has a self-healing effect and has good long-term life characteristics such as 60 ° C humidity resistance guarantee. There is a need for the development of simple moldless chip capacitors.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a compact surface-mountable moldless capacitor having a self-healing action and a high potential gradient.

Means for Solving the Problems A dielectric film made of a plastic film, a vapor deposition electrode layer formed between the dielectric films, at least one surface of the dielectric film, and the vapor deposition electrode layer facing the dielectric film A release agent layer formed therebetween and an end face electrode joined to the end face of the vapor deposition electrode with each other and alternately bonded to the vapor deposition electrode, and subjected to a heat aging treatment for imparting heat resistance. .

Further, as the release agent, one of a silicone degrading agent and a fluorine-based releasing agent, or a mixture thereof is used.

In addition, a step of winding or laminating a single-sided or double-sided metallized film, a step of forming an end face electrode on an end face of a vapor deposition electrode, and a step of impregnating a release agent between metallized film layers, and imparting heat resistance to the capacitor element And at least a heat aging step.

Further, a polyethylene naphthalate film or a polyphenylene sulfide film is used as the dielectric film, and heat aging at 200 ° C. or more is performed.

Action Filmless capacitor having such a structure and a method of manufacturing the same, and a film that inhibits a self-healing action due to a release agent present between layers even when a plastic film dielectric is subjected to a high-temperature heat aging treatment by a manufacturing method thereof. The occurrence of strong bonding between the layers can be suppressed,
Therefore, the self-healing action of the original metallized film capacitor is exhibited, and a high potential gradient moldless chip type film capacitor can be obtained.

In addition, a silicone-based release agent (for example, dimethylpolysiloxane or the like) or a fluorine-based release agent (for example, fluoroalkyl phosphate) having sufficient heat resistance can be used as the interlayer release agent of the present invention. Thus, a moldless chip type film capacitor having sufficient heat resistance can be obtained. And since these silicone type and fluorine type compounds take a crosslinked (network) structure, and this network structure is relatively large and the moisture permeability is good,
Moisture resistance is greatly improved. The phenomenon of improving the moisture resistance characteristics is that, for example, changing the semiconductor junction coating material of the semiconductor chip from an epoxy resin to a silicone resin substantially eliminates corrosion of aluminum vapor-deposited wiring, and significantly improves moisture resistance characteristics. It can be understood on the basis of the same principle.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

(Example 1) On a dielectric film 6 made of a 2.7 μm thick PEN film,
A single-sided metallized film on which a 300 mm thick aluminum vapor-deposited electrode 7 was formed was prepared and laminated, and then metal was sprayed on the end face to form the end face electrode 3. The surface of the end face electrode 3 is covered with solder to form a solder plated electrode 4. The mother capacitor element is immersed for a predetermined time in a release agent solution containing a fluoroalkyl phosphate ester as a main component, and then the capacitor element is taken out.The element is subjected to a heat treatment to disperse the solvent contained in the release agent solution. Was. In this way,
The mother capacitor element impregnated with the release agent 8 between the film layers is subjected to a heat aging treatment for a predetermined time while gradually increasing the temperature and in an atmosphere at a maximum temperature of 230 ° C. while applying appropriate pressure in the film laminating direction of the element. Was. Then, the mother capacitor element obtained in this way is used, if necessary,
Cut to a predetermined length, cover the cut surface 2 with a simple protective film 5,
A moldless chip type capacitor 1 having a configuration as shown in FIG. 1 was obtained.

FIG. 2 shows the initial step-up breakdown characteristics of the chip capacitor when a DC voltage is applied, and FIG. 3 shows the humidity resistance load characteristics.

(Example 2) On the dielectric film 6 composed of a 2.7 μm thick PEN film,
A single-sided metallized film on which a 300 mm thick aluminum vapor-deposited electrode 7 was formed was prepared and laminated, and then metal was sprayed on the end face to form the end face electrode 3. The surface of the end face electrode 3 is covered with solder to form a solder plated electrode 4. The mother capacitor element was immersed in a release agent liquid containing methylhydrogenpolysiloxane as a main component, and left under a vacuum atmosphere for a predetermined time to perform vacuum impregnation. Thereafter, the capacitor element was taken out, the element was subjected to a heat treatment, and the silicone-based release agent was cured. In this manner, while gradually increasing the temperature of the mother capacitor element impregnated with the release agent 8 between the film layers, heat aging is performed for a predetermined time in an atmosphere at a maximum temperature of 230 ° C. while applying appropriate pressure in the film laminating direction of the element. Processing was performed. Thereafter, the mother capacitor element thus obtained is cut to a predetermined length, if necessary, and the cut surface 2 is covered with a simple protective film 5 to obtain a moldless chip type capacitor having a configuration as shown in FIG. 1 was obtained.

FIG. 2 shows the initial step-up breakdown characteristics of the chip capacitor, and FIG. 4 shows the humidity resistance load characteristics.

Example 3 A dielectric film 6 made of a 2.0 μm thick PPS film was
A single-sided metallized film on which a 300 mm thick aluminum vapor-deposited electrode 7 was formed was prepared and laminated, and then metal was sprayed on the end face to form the end face electrode 3. The surface of the end face electrode 3 is covered with solder to form a solder plated electrode 4. The mother capacitor element was immersed in a release agent solution containing a fluoroalkyl phosphate as a main component for a predetermined time, and then the element was taken out. The element was subjected to a heat treatment to disperse the solvent contained in the release agent solution. . In this way, the mother capacitor element impregnated with the release agent between the film layers is heated for a predetermined time under an atmosphere of a maximum temperature of 260 ° C. while applying appropriate pressure in the film laminating direction of the element while gradually increasing the temperature. Aging treatment was performed. Thereafter, the mother capacitor element thus obtained is cut to a predetermined length, if necessary, and the cut surface 2 is covered with a simple protective film 5 to obtain a moldless chip type capacitor having a configuration as shown in FIG. 1 was obtained.

FIG. 3 shows the initial step-up breakdown characteristics of the chip capacitor, and FIGS. 5 (a) to 5 (c) show the moisture resistance load characteristics.

(Comparative Example 1) Approximately 30 on the derivative film 16 composed of a 2.7 μm thick PEN film.
A single-sided metallized film on which a 0-mm thick aluminum vapor-deposited electrode 17 was formed was prepared and laminated, and then a metal was sprayed on an end face to form an end face electrode 13. The surface of the end face electrode 13 is covered with solder to form a solder plated electrode 14. afterwards,
The mother capacitor element was subjected to a heat aging treatment for a predetermined period of time in an atmosphere at a maximum temperature of 230 ° C. while applying an appropriate pressure in the film laminating direction of the element while gradually increasing the temperature. Thereafter, the mother capacitor element thus obtained is cut to a predetermined length, if necessary, the cut surface 12 is covered with a simple protective film 15, and a moldless chip type capacitor having a configuration as shown in FIG. I got 11.

FIG. 2 shows the initial step-up breakdown characteristics of this chip capacitor, and FIGS. 4 (a) to 4 (c) show the moisture resistance load characteristics.

(Comparative Example 2) On the derivative film 16 made of a 2.0 µm thick PPS film, about 30
A single-sided metallized film on which a 0-mm thick aluminum vapor-deposited electrode was formed was prepared and laminated, and then a metal was sprayed on the end face to form an end face electrode 13. The surface of the end face electrode 13 is covered with solder to form a solder plated electrode 14. Thereafter, the mother capacitor element was subjected to a heat aging treatment for a predetermined time in an atmosphere at a maximum temperature of 260 ° C. while gradually increasing the temperature while applying an appropriate pressure in the film laminating direction of the element. Thereafter, the mother capacitor element thus obtained is cut to a predetermined length, if necessary, the cut surface 12 is covered with a simple protective film 15, and a moldless chip type capacitor having a configuration as shown in FIG. I got 11.

FIG. 3 shows the initial step-up breakdown characteristics of the chip capacitor, and FIGS. 5 (a) to 5 (c) show the moisture resistance load characteristics.

The initial step-up breakdown characteristics (FIG. 2) and the humidity resistance load characteristics (FIGS. 4 (a) to (c)) of the chip capacitors of the present invention obtained in Example 1 and Example 2 were obtained in Comparative Example 1. It can be seen that the chip capacitor has characteristics superior to those of the chip capacitor (FIGS. 2 and 4 (a) to (c)).

Further, the initial step-up breakdown characteristics (FIG. 3) and the moisture resistance load characteristics (FIGS. 5A to 5C) of the chip capacitor of the present invention obtained in Example 3 are also obtained by the chip obtained in Comparative Example 2. It can be seen that the capacitor has characteristics superior to those of the capacitor (FIGS. 3 and 5 (a) to (c)).

In the first embodiment, the main component of the release agent solution is a fluorine-based release agent. However, a silicone-based release agent, another release agent having heat resistance, or a mixed solution thereof may be used.

In Example 2, a thermosetting type silicone compound was used as a main component as a release agent. However, each of a silicone type release agent or a fluorine type release agent of a hardening, gelling, and oily type capable of vacuum impregnation, or In addition, a release agent having heat resistance or a mixture thereof may be used.

Further, in this embodiment, as the dielectric film, PE
Although the N film and the PPS film used aluminum as the material for the vapor deposition electrode, it is clear that the effects of the present invention can be obtained in other combinations.

Note that, in the present embodiment, the case where the laminated capacitor element is formed using the single-sided metallized film has been described, but the wound capacitor element using the single-sided metallized film and the double-sided metallized film were used. It is apparent that the effects of the present invention can be obtained even with a multilayer capacitor element or a wound capacitor element.

According to the present invention, as is apparent from the above description of the embodiment, the self-recovery action inherent to the metallized film capacitor is exhibited, the potential gradient can be made higher than that of the conventional product, and the size and solder size can be reduced. A moldless type chip capacitor having heat resistance and high reliability can be obtained. In addition, by using a silicone-based release agent or a fluorine-based release agent as an interlayer release agent, it is possible to significantly improve the moisture resistance characteristics as compared with the related art while securing sufficient heat resistance as a chip-type capacitor. And the like.

[Brief description of the drawings]

FIG. 1 (a) is a partially cutaway perspective view showing a configuration of a chip-type metallized film capacitor according to one embodiment of the present invention, and FIG. 1 (b) is a sectional view taken along line AA of FIG. 1 (a). FIG. 2 is a diagram showing the results of the initial step-up breakdown test of Examples 1 and 2 and Comparative Example 1, FIG. 3 is a diagram showing the results of the initial step-up breakdown test of Example 3 and Comparative Example 2, and FIG. ) Is a diagram showing a change in capacitance of each of Examples 1 and 2 and Comparative Example 1 by a humidity resistance test at 60 ° C.
FIG. 4 (b) is a diagram showing the change in tan δ, FIG. 4 (c) is a diagram showing the change in insulation resistance, and FIG. 5 (a) is a result of a 60 ° C. humidity resistance load test of Example 3 and Comparative Example 2. FIG. 5 (b) shows the same tan δ change, FIG. 5 (c) shows the same insulation resistance change, and FIG. 6 (a) shows the conventional chip type metallization. FIG. 6 (b) is a sectional view taken along the line BB of FIG. 6 (a), and FIG. 7 is a view showing a self-recovery action mechanism of the metallized film capacitor. is there. 1 ... Moldless chip type film capacitor, 2 ...
... cut surface, 3 ... end surface electrode, 4 ... solder plating electrode,
5: simple protective film, 6: dielectric film, 7: vapor-deposited electrode layer, 8: release agent, 9: margin.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Chiichi Ozasa 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-company (58) Field surveyed (Int.Cl. ⁶ , DB name) H01G 4/00-4/40

Claims (4)

(57) [Claims] 1. A dielectric film made of a plastic film, a vapor deposition electrode layer formed between the dielectric films, and a gap between at least one surface of the dielectric film and the vapor deposition electrode layer facing the dielectric film. A chip-type metallized film having a release agent layer to be formed and end face electrodes which are respectively joined to the end faces of the vapor deposition electrodes and are alternately connected to the vapor deposition electrodes, and which have been subjected to a heat aging treatment for imparting heat resistance. Capacitors. 2. The chip-type metallized film capacitor according to claim 1, wherein one of a silicone-based release agent and a fluorine-based release agent is used as the release agent. 3. A step of winding or laminating a one-sided or two-sided metallized film, a step of forming an end face electrode on an end face from which a vapor deposition electrode is drawn out, a step of impregnating a release agent between metallized film layers, A method for producing a chip-type metallized film capacitor, comprising at least a heat aging step for imparting properties. 4. The method for producing a chip-type metallized film capacitor according to claim 3, wherein a polyethylene naphthalate film or a polyphenylene sulfide film is used as the dielectric film and heat aging is performed at 200 ° C. or more.