JPH0670945B2 - Double-sided metallized film capacitor - Google Patents

Description

FIELD OF THE INVENTION This invention relates to double-sided metallized film capacitors.

2. Prior Art FIG. 2 shows a schematic structure of a conventional metallized film capacitor element part. Reference numeral 11 is a polyolefin film such as polypropylene or polyethylene, and 12 is a vapor deposition film formed on one surface of the film 11. A metal such as aluminum or zinc is used as the vapor deposition metal. 13 is a metallikon layer for leading out the electrode. Furthermore, in a conventional wax-impregnated type capacitor, a mixture of paraffin wax, polybutene oil, polyethylene oligomer, etc. is used, and the mixing ratio of normal paraffin in the impregnating agent is about 50% by weight. .

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described conventional configuration, since the dielectric and the electrode are formed of the single-sided metallized polyolefin film, the number of man-hours for forming the metal vapor deposition film becomes large, and eventually the capacitor is formed. There is a drawback that the device cost is high. Therefore, attempts have been made to metallize both surfaces of the polyolefin film. However, as the impregnating agent for a capacitor equipped with a double-sided metallized polyolefin film and a laminated film, if a normal paraffin mixing ratio of 50% by weight or more is used, a conventional single-sided metallized polyolefin film capacitor is used. It is difficult to obtain the same level of performance as that obtained by impregnating conventional impregnating agents.

The present invention solves the above conventional problems.

Means for Solving the Problems In order to achieve this object, the present invention is characterized in that a double-sided metallized polyolefin film and a laminated film are used, and an impregnant having a normal paraffin mixing ratio of 40% by weight or less is used. And

When the paraffin wax (and a part of polybutene insulating oil are mixed) is used for the capacitor including the double-sided metallized polyolefin film and the laminated film as described above, the film swells and the volume increases. However, as described above, when composed of different materials such as a double-sided metallized polyolefin film and a laminated film, the swellability is different, a dimensional change occurs between the two, and eventually a void is generated. The generation of voids is suppressed by setting the mixing ratio to a certain value or less. Therefore, electrical deterioration is reduced.

Example FIG. 1 is a partial schematic cross-sectional view of a capacitor formed by using the double-sided metallized polyolefin film according to the present invention. In the figure, 1 is a polyolefin film such as polypropylene or polyethylene. 2 is a vapor-deposited metal such as aluminum or zinc. Reference numeral 3 denotes a laminated film, which may be a polyolefin film such as polypropylene or polyethylene, a polyester film, a polyphenylene sulfide film, a polysulfone film, a Kapton film, or a polyvinylidene fluoride film. Four
Is a metallikon layer for leading out the electrode.

Reference numeral 5 denotes an impregnating agent. In the structure shown in FIG. 1, the life characteristics of the capacitor differ depending on the type of impregnating agent. Especially when the swelling properties of the vapor-deposited film and the laminated film are different, a great difference occurs in the life characteristics. Tables 1 and 3 show a comparison of the characteristics of the capacitors when polypropylene was used as the laminated film and the mixing ratio of the normal paraffin of the impregnating agent was variously changed. The capacitor sample was 50 μF, and the trial application was performed at 60 ° C. and 300 V.

From FIG. 3 and Table 1, those having a normal paraffin content of 40% by weight or less (Examples 1 to 3) satisfy the JIS standard,
Further, those of 50% by weight or more (Comparative Examples 1 to 3) do not meet the requirements and cannot be put to practical use. When the mixing ratio of normal paraffin in the impregnating agent becomes high, the swelling of the polyolefin becomes large, and the swelling between the vapor-deposited film and the laminated film causes a large dimensional difference, which causes wrinkles in the laminated film, which forms voids. However, when a voltage is applied between the electrodes, corona discharge occurs, which causes deterioration of the insulating material and reduction of the capacity due to oxidation of the electrode film.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to maintain the excellent electric characteristics of the double-sided metallized film capacitor, which greatly contributes to the practical application of the double-sided metallized polyolefin film capacitor.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a main part of a capacitor using a double-sided metallized polyolefin film according to the present invention, FIG. 2 is a schematic sectional view of a conventional capacitor using a single-sided metallized film, and FIG. 3 is a life of the capacitor. It is a figure which shows the comparison of a characteristic. 1 ... Polyolefin film, 2 ... Evaporated film, 3 ...
Laminated film, 5 ... Impregnating agent.

Claims (1)

[Claims] 1. A double-sided metallized polyolefin film and a laminated film are provided, and the mixing ratio of normal paraffin is
A double-sided metallized film capacitor characterized by using an impregnating agent of 40% by weight or less.