JPS59121819A - Condenser - 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 Field of Industrial Application This invention relates to capacitors using metallized films.

Conventional structure and problems Metallized film capacitors are generally made by winding a metalized film, then wrapping several layers of non-metalized film around the outermost periphery to form a capacitor element, and then flattening it with heat and pressure. Electrodes were formed either by molding, or by leaving it in the cylindrical shape after winding, and melting and spraying metal such as zinc or tin onto the ends (metallicon). At that time, masking was performed using various methods to prevent metallicon particles from adhering to the outermost surface of the capacitor element, but masking could not be carried out completely when the shape of the capacitor element was small. As a result, metallicon particles adhere to the outermost surface of the capacitor element, resulting in defects such as a decrease in insulation resistance.

In order to remove these adhered metallicon particles, a method of mechanically removing them with visual confirmation is generally used, but in the past, a colorless and transparent film such as polyester or polypropylene was used as a protective insulating material on the outermost periphery of the element. is used, and even if metallic particles with a grayish metallic color adhere to the surface, it is difficult to identify and remove them, and as they cannot be completely removed, short circuits may occur due to bridges of attached metallic particles. However, the insulation resistance and dielectric loss tangent deteriorated, causing a decrease in reliability. Furthermore, during removal, the film may peel off, which poses a major problem in terms of properties and appearance.

Purpose of the Invention The purpose of the present invention is to easily identify and remove metallicon particles that adhere to the surface of the insulating film covering the outermost periphery of a capacitor element during electrode formation, thereby reducing insulation resistance defects and improving reliability. It is an object of the present invention to provide a capacitor that can be improved.

Structure of the Invention The capacitor of the present invention has a capacitor element formed by winding or laminating a metallized film, the outermost periphery of which is coated with a colored insulating film having a colored coating layer formed on one or both sides of a plastic film, and a metallized film is coated on the end face of the element. It has an edge electrode formed thereon.

In this way, by using a colored insulating film, the metallicon particles attached to the outer surface of the film have completely different hues, making it easy to visually identify the metallicon particles, and ensuring the metallicon particles are removed. It is uruno.

Description of examples An embodiment of this invention will be described based on the drawings.

That is, in this capacitor, the outermost periphery of a capacitor element 1 wound with a metallized film is covered and protected with a colored insulating film 4, and then the end i 1 a of the capacitor element 1 is covered with a colored insulating film 4.
Electrodes were formed on the end surface 1a by spraying hemetalicon particles.

The colored insulating film 4 is made by mixing a red dye into a resin (such as a modified polyether type polyester resin) that is non-tacky at room temperature and sticky at 60° C. or higher on one side of a transparent or translucent plastic film 2. A colored coating layer 3 is provided over almost the entire surface. The colored insulating film 4 is wound around the outermost circumference of the capacitor element 1 so that the coating layer 3 is on the inner surface, and then heat-sealed to the main body of the capacitor element 1 by heating using a heat press or the like. Note that, for convenience of explanation, the drawing shows the insulating film 4 in an expanded state near its end.

With this configuration, the end face 1a of the capacitor element 1
Even if the hemetallicon particles are sprayed, the outermost part of the capacitor element 1 is coated with a red-colored insulating film, so the color of the metallicon particles adhering to the outermost part of the element is grayish and metallic. The particles are completely different and can be easily identified visually, making it easier to remove metallicon particles.

Next, the capacitor obtained in this example and the conventional capacitor obtained by winding a plastic film without a colored coating layer around a capacitor element: 77'7? Metallicon particles were sprayed on each end face, and then metallicon particles adhering to the outermost periphery were removed, and the insulation resistance defect rate and appearance defect rate were investigated. The results are shown in the table below.

As is clear from the table, by protecting and insulating the outermost part of the capacitor element 1 with the plastic film 2 having a colored coating layer 3 for easy identification, metallicon particles adhere to the surface of the plastic film 2 and form electrodes. Metallicon particles that cause short circuits can be easily removed, significantly reducing the defective insulation resistance rate and contributing to improved capacitor characteristics and reliability.

Furthermore, a colored coating layer 3 made of a resin that is non-adhesive at room temperature and tacky at 60° C. or above is provided on the inner surface of the plastic film 2, so that it can be easily heat-treated or the capacitor element 1
The plastic film 2, the capacitor element, and the overlapping film 2 are firmly bonded to each other by the heat during thermoforming. It is possible to prevent peeling of the insulating film 4 and the occurrence of film cracks, etc., and as a result, as mentioned above, the appearance defect rate can be significantly reduced.

It should be noted that, instead of the plastic film 2 provided with the colored coating layer 3, it is possible to add a coloring agent in advance to color the film 2 at the time of manufacturing, which will of course make it easier to identify and remove the metallicon particles. Coloring the film at the time of manufacturing increases costs, has problems with film manufacturing technology and productivity, and has many problems such as an increase in insulation defects in the film.
Undesirable.

Further, in this embodiment, a case has been described in which the colored coating layer 3 is provided only on one side (inner surface) of the plastic film 2, but the colored coating layer 3 may be provided on both sides of the plastic film 2. At that time, coloring agents such as dyes and pigments are mixed into the colored coating layer 3.
It is possible to use a non-adhesive resin as the resin forming the capacitor element 1 and apply an adhesive to the inner surface of the capacitor element 1 to adhere it to the capacitor element 1. Further, the coloring agent mixed into the colored coating layer 3 is not limited to a red one, and any coloring agent can be used as long as the attached metallicon particles can be easily identified.

Effects of the Invention As described above, according to the present invention, metallic particles attached to the surface of the insulating film that covers and protects the outermost periphery of the capacitor element can be easily identified, thereby reducing insulation resistance defects and improving reliability. It has the effect of improving.

[Brief explanation of the drawing]

The drawing is a perspective view of one embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Capacitor element, la... End surface, 2... Plastic film, 3... Colored coating layer, 4
...Colored insulation film 81

Claims (3)

[Claims] (1) A capacitor element made by winding or laminating a metallized film, a colored insulating film that covers and protects the outermost periphery of the element by forming a colored coating layer on one or both sides of a plastic film, and a metallized film at the end of the element. A capacitor with electrodes formed by. (2) The capacitor according to claim (1), wherein the colored insulating film is a transparent or translucent plastic film that covers the outermost periphery of the content element, and the inner surface of the transparent or translucent plastic film is coated with a resin or glue containing a colorant. . (3) The capacitor according to claim (2), wherein the resin or glue is non-tacky at room temperature and sticky at temperatures above 60'C, and the colored insulating film is heat-sealed around the outer periphery of the content element.