JPH0770413B2 - Method of manufacturing film capacitor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a film capacitor used in electronic equipment and electric equipment.

Conventional Technology Conventionally, capacitors are made of polyphenylene sulfide (hereinafter
PPS) is formed on both sides of a dielectric film made of aluminum and vapor-deposited electrodes made of aluminum are formed on it, a coating dielectric made of polyphenylene oxide (hereinafter abbreviated as PPO) is formed on it, cut to a specified size, and double-sided vapor-deposited. After making a double-sided coating film, then stacking hundreds of double-sided vapor-deposited double-sided coating films, forming a metallikon layer made of brass for electrical connection to the vapor deposition electrode and forming a mother capacitor, then 90 to 120 ° C It is heated up to 200 ° C to remove the residual solvent in the coating dielectric, aged at 200 ° C for 1 hour, milled to a certain size to make a capacitor element, and the comb leads are welded and then the epoxy resin is used to mold the exterior. The finished product was made by processing the comb lead as an external electrode.

Problems to be Solved by the Invention In recent years, the demand for reliability is increasing more and more in electronic devices and electric devices, and in the past, the humidity resistance was 40 ° C, the relative humidity was 95%, and the guarantee time was 1000 hours. 60
Demand has risen for 1000 hours at ℃ and 95% relative humidity.

Conventional film capacitors had the problem of deterioration in electrical characteristics such as a decrease in capacitance of 10% or more after 500 hours and a large increase in loss angle under conditions of 60 ° C and 95% relative humidity. In the capacitor with the deteriorated electrical characteristics, the vapor deposition electrode in the exposed portion without the coating dielectric near the methacholine layer disappeared.

It is an object of the present invention to obtain an inexpensive capacitor that can be guaranteed for humidity for 1000 hours at a temperature of 60 ° C. and a relative humidity of 95%.

Means for Solving Problems The cause of deterioration of electrical characteristics after 500 hours at a temperature of 60 ° C. and a relative humidity of 95% is the dew condensation on the exposed vapor deposition electrode, and the water and aluminum cause a chemical reaction to cause aluminum hydroxide or oxidation. This is because it changed to aluminum and became an insulator.

Therefore, the present invention utilizes an oligomer contained in PPS by heat-treating a capacitor element or a mother capacitor, and heat-flows out or vaporizes to form a thin film of the oligomer on the vapor deposition electrode to suppress the influence of dew condensation. It is trying to solve it.

Action In the present invention, therefore, by applying heat to the capacitor element or the mother capacitor, the oligomer flows out or vaporizes from the PPS film to form an oligomer thin film of several to several tens of Å on the aluminum vapor deposition electrode, and the oligomer thin film is condensed to form aluminum. By protecting the vapor deposition electrode, it is possible to guarantee 2000 hours at 40 ° C and 95% relative humidity or 1000 hours at 60 ° C and 95% relative humidity. The presence of the oligomer layer was revealed by the fact that the sulfur component was detected as a result of ESCA analysis of the surface of the aluminum vapor deposition electrode.

EXAMPLES The present invention will be described below.

(Example 1) A vapor deposition electrode made of aluminum having a thickness of 400 Å was formed on both sides of a dielectric film made of a PPS film having a thickness of 2 μm (containing 1% by weight of an oligomer), and a dielectric film having a thickness of 1 μm was formed thereon. Make a long double-sided vapor deposition double-sided coating film with a width of 5 mm by forming a coating dielectric made of PPO, then 500
After obtaining the capacitor strips by stacking the metallicon layers of brass with a thickness of 0.5 mm on both sides of the stacking surface
After performing the heat treatment shown in the table, make a capacitor element by milling with a width of 3 mm, weld this capacitor element to the comb lead, apply a 0.5 mm thick mold exterior with epoxy resin, and then remove the comb lead. External electrodes were formed by individually separating and bending a part to obtain capacitors.

(Conventional example 2) Next, as a conventional example, the capacitor strip obtained in the example was subjected to 200 ° C.
After heat treatment for a period of time, a capacitor was obtained through the same steps as in the example.

Each of the capacitors of the present invention and the conventional example obtained as described above is
Table 1 shows the life time and heat treatment conditions, where the time when the rate of change in capacitance becomes negative when left in an atmosphere of 100 at a humidity of 60 ° C and a relative humidity of 95% is shown in Table 1. As a result, it has been found that the moisture resistance of the present invention can be greatly improved and the oligomer layer has a function of improving the moisture resistance of the capacitor. It was also found that the heat treatment conditions are closely related to the outflow amount of the oligomer.

Further, similar results were obtained when the wound capacitor element was used.

EFFECTS OF THE INVENTION According to the present invention, a capacitor element or a capacitor strip using a PPS film containing an oligomer is subjected to heat treatment at a temperature of 40 ° C. and a relative humidity of 95% for 200 hours or at a temperature of 60 ° C. and a relative humidity of 95%. It is possible to guarantee for 1000 hours.

Also, as a method for increasing the moisture resistance, it is only necessary to install a heating furnace in the middle of the process, so the equipment cost is lower than other methods, and other characteristics of the capacitor can be manufactured reasonably without being adversely affected. However, it is extremely valuable to be able to reduce costs and improve productivity.

Front page continuation (72) Inventor Nobuki Sunagure 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kenji Kuwata, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. Kenji Ishida 1006, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Nobuyuki Kume, No. 1006, Kadoma, Kadoma City, Osaka Pref., Matsushita Electric Industrial Co., Ltd. Kadoma 1006, Matsushita Electric Industrial Co., Ltd. (56) References JP-A-61-102021 (JP, A) JP-A-62-158312 (JP, A)

Claims (1)

[Claims] 1. A capacitor element in which a polyphenylene sulfide film containing an oligomer is subjected to metal vapor deposition, and a dielectric resin is further formed thereon by coating, and these are wound or laminated at a temperature of 180 ° C. or more for 10 hours or more. A method for producing a film capacitor, which comprises subjecting an oligomer in a polyphenylene sulfide film to flow out or vaporization from the film by heat treatment to form a thin film on a metal vapor deposition film.