JPH0437108A - Manufacturing method of multilayer film capacitor - 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 Fields of Application The present invention is directed to a compensation method which is used in general electronic equipment and is applied to an insulating film in which a dielectric film is sandwiched between a metallized film and a metal film deposited on an insulating film. This invention relates to a method for forming a dielectric film for an acoustic film capacitor.

Conventional technology Conventionally, the dielectric film of a horizontal one-film capacitor is formed by dissolving a dielectric material in a solvent, lacquering both sides or one side of a double-sided metallized film, and then evaporating the solvent in a hot air oven. ing. However, in the current situation where there is a strong demand for miniaturization in the market, when making film capacitors smaller by thinning the dielectric film, it is difficult to maintain the same voltage resistance characteristics as conventional products even if the dielectric film is made thinner. is necessary.

In this way, after lacquering the paint D, the solvent is rapidly evaporated to form a dielectric film (as the solvent evaporates, voids are generated inside the dielectric B-iI and the surface roughness becomes rough.

When a voltage is applied to such a dielectric film, voids inside the dielectric film and roughness of the surface cause a drop in dielectric breakdown voltage.

Methods to suppress the amount of solvent evaporation after lacquering, reduce voids inside the dielectric film, and improve surface roughness include changing the solvent, increasing the concentration of the dielectric material in the paint, and slowing down the solvent drying speed. Attempts have been made and various proposals have been made.

Problems to be Solved by the Invention However, if the amount of evaporation of the solvent is suppressed by changing to a high-boiling solvent, the amount of solvent remaining in the dielectric film will increase, causing various problems when the film capacitor is torn down. Negative impact on custom orders. Also, the dielectric material eave height of the paint! ! As a result, the absolute amount of solvent decreases and the viscosity τ increases, resulting in poor lacquering properties.

Also, slowing down the solvent drying speed reduces the voluntariness.

The present invention solves the above-mentioned problems, and aims to provide a multilayer film capacitor with improved withstand voltage characteristics by reducing voids inside the dielectric film after lacquering and improving surface roughness.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention' is a method in which a paint made by dissolving a material for forming a dielectric film in a solvent is metallized on both sides.
After lacquering at least one surface of the film, a dielectric film is formed by heating while applying pressure.

Effect By heating the dielectric film after lacquering while applying pressure as described above, the generation of voids inside the dielectric film during the formation of the dielectric coating film is suppressed, and the growth of voids once generated is also suppressed. It grows to a size that poses a problem and becomes a female. Therefore, the withstand voltage characteristics of the completed dielectric film are improved.

Examples Below, please refer to FIGS. 1 to 3 for implementation sequences of the present invention.
I will explain while doing so.

Example (1) A dielectric film whose dielectric material is polyphenylene oxide and whose film thickness is 8 μmar is heated and pressurized using a heat flux machine.The applied temperature is 80°C and 13o°C.
, 1so'(:, 17oC, 1e.

The dielectric film of the present invention is formed by setting the C1 pressure to to, p/, 4, and heating/pressing time 5 seconds. The withstand voltage characteristics of the dielectric film formed by the above method were superior to those of conventional dielectric films.

FIG. 1 (IL), (kl) shows a comparison of the custom-made withstand voltage per unit thickness between the dielectric film formed in this example and a conventional dielectric film. In the figure, the marks * indicate the average values of the conventional dielectric film, and the marks * indicate the average values of the present invention. The vertical line attached to the average value indicates the range of variation in the experimental values.

The same applies to each of the following figures. The average initial discharge voltage per unit thickness is at most 19 V/μm, and the average breakdown voltage is at most 1 s□V/μm. The initial discharge voltage described here refers to the initial electrical work at the interface between the dielectric film and the double-sided metallized film, when the metal in the defective area scatters and the insulation is restored, and it is the dielectric breakdown voltage that functions as a toma film capacitor. He is an electrician who will disappear.

Example (2) The conditions for forming the dielectric film in Example (2) were the same as those in Example (1), and the dielectric film of the present invention was formed by heating and pressurizing the dielectric film for 16 seconds. Shape, taste. The withstand voltage characteristics of the dielectric film formed by the above method were superior to those of conventional dielectric films. FIG. 2 (!L) and (b) show a comparison of the withstand voltage characteristics per unit thickness between the dielectric film formed in this example and a conventional dielectric film.

The average initial discharge voltage per unit thickness is up to 26'
i/1tm, breakdown voltage is maximum 11QV/
Improved by μm.

Example (3) The applied temperature was 160°C, and the applied pressure was 1 og/c, f.

2009/cA,'00g/ca,eoog/clr
+800, @ /c, J, 10009 /c4. A dielectric film of the present invention is formed in the same manner as in Example (1) using a pressure and heating time of 6 seconds. Dielectric film!
It was a bit disappointing. 11) and (b) show a comparison of the custom-made withstand voltage per unit thickness between the dielectric film formed in this example and a conventional dielectric film. The initial discharge voltage 111E' per unit thickness is a maximum of 32v/μm on average, and the dielectric breakdown voltage riE! d average current up to 215 V/ltm.

Although polyphenylene oxide is used as the dielectric film material in each of the examples above, polycarbonate or polyester can also be used as the dielectric film material and have the same effect of improving withstand voltage characteristics.

Furthermore, as is clear from the withstand voltage characteristic diagrams shown in each of the above examples, the paint was prepared so that the dielectric film thickness ranged from 0.1 μm to S, O μm, and the dielectric film after lacquering was Heating at a temperature of 190'C to 190'C
0. ! Applying a pressure of i'/cJ to 1ooooji/J for a period of 0.1 seconds to 60 seconds is particularly effective in reducing voids inside the dielectric film and improving surface roughness. It has a remarkable effect on improving the durability of the dielectric film.

In this example, a heat press machine was used as a means for heating and pressurizing the dielectric film, but a hot roller or the like may be used as other means, and the dielectric film may be heated and pressurized after lacquering. The withstand voltage characteristics can be improved by
You can achieve your intended purpose.

Effects of the Invention As described above, by heating and pressurizing the 'd1 dielectric film according to the present invention, voids inside the dielectric film can be reduced and surface roughness can be improved. Therefore, by increasing the density of the dielectric film, the withstand voltage characteristics can be improved, and reliability can be improved.

[Brief explanation of drawings]

Figure 1゛! L), (b), Figure 2! ,! L),
(b), FIG. 3+a), and (b) are diagrams showing a comparison between a dielectric film according to the present invention and a conventional dielectric film, which are custom-made with a withstand voltage of a specific unit thickness. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1 figure ia*fi overturned (・C) MJ 11! ! *7! (・υ 11J heat abuseff ("(J my temperature (@C) Initial discharge voltage (vism-) of shore level obstacle a+sr-) 薯*tf[FtJ+island 7': 1.Iff) 11mHk:
am electric Fk (VIEsuJ

Claims (3)

[Claims] (1) A method for forming a dielectric film for a laminated film capacitor, which comprises lacquering at least one side of a double-sided metallized film with a paint prepared by dissolving a dielectric film material in a solvent, and then heating the film while applying pressure. (2) The method for forming a dielectric film for a multilayer film capacitor according to claim (1), wherein the dielectric film material is polycarbonate, polyphenylene oxide, or polyester. (3) Film thickness of dielectric film material ranges from 0.1 μm to 5.0 μm
μm, heating temperature from 80℃ to 190℃, pressure 10
The method for forming a dielectric film of a multilayer film capacitor according to claim 1, wherein the dielectric film is formed in a range of g/cm^2 to 1000 g/cm^2 and a heating and pressurizing time is 0.1 seconds to 60 seconds.