JPS6316891B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD This invention relates to a capacitor using a metallized film. Conventional structure and its 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 when the shape of the capacitor element is small, it is difficult to completely mask the capacitor element. Metallicon particles adhered to the outermost peripheral surface of the device, causing defects such as a decrease in insulation resistance. In order to remove these attached metallicon particles, a method is generally used to mechanically remove them by visual inspection, but in the past, a colorless and transparent film such as polyester or polypropylene was generally used as a protective insulating material for the outermost periphery of the element. is used,
Even if metallicon particles, which have a grayish metallic color, adhere to the surface, it is difficult to identify and remove them, and since they cannot be completely removed, bridges of the adhered metallicon particles may cause short circuits, causing insulation resistance and dielectric The tangent deteriorated, causing a decrease in reliability. Further, during removal, the film may turn over, which poses a major problem in terms of properties and appearance. Purpose of the Invention An object of the present invention is to be able to easily identify and remove metallicon particles that adhere to the surface of an insulating film covering the outermost periphery of a capacitor element during electrode formation, thereby reducing insulation resistance defects and improving reliability. The purpose of the present invention is to provide a capacitor that can improve the performance. Structure of the Invention The capacitor of the present invention has a colored insulating film formed by forming a colored coating layer on one or both sides of a plastic film on the outermost periphery of a capacitor element formed by winding or laminating a metalized film, and a colored insulating film formed with a colored coating layer on one or both sides of the plastic film. This is an electrode formed. In this way, by using a colored insulating film, the metallicon particles adhering to the outer peripheral surface of the film have different hues, making it easy to visually identify the metallicon particles and making it easier to remove the metallicon particles. It can definitely be done. DESCRIPTION OF EMBODIMENTS An embodiment of the present 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 metallicon particles are sprayed onto the end surface 1a of the capacitor element 1 to form an electrode on the end surface 1a. It was formed. 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 the transparent or translucent plastic film 2. colored coating layer 3 formed by
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. In addition,
For convenience of explanation, the drawing shows the insulating film 4 in an expanded state near its end. With this configuration, even if metallicon particles are sprayed onto the end surface 1a of the capacitor element 1, the outermost periphery of the capacitor element 1 is covered with the red-colored insulating film. The hue of the metallicon particles, which have a metallic color with a gray color, attached to the surface of the metallicon particles is completely different and can be easily identified visually, making it easy to remove the metallicon particles. Next, metallicon particles were sprayed onto the end faces of the capacitor obtained in this example and the conventional capacitor obtained by wrapping a plastic film without a colored coating layer around a capacitor element, and then the outermost periphery of the capacitor was sprayed with metallicon particles. The defective rate of insulation resistance and the defective appearance rate were investigated for those in which metallicon particles attached to the surface were removed. The results are shown in the table below.

[Table] 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 so that the metallicon particles can be easily identified, the metallicon particles adhere to the surface of the plastic film 2. Metallicon particles that short-circuit the electrodes can be easily removed, significantly reducing the insulation resistance defect 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 sticky at 60° C. or higher is provided on the inner surface of the plastic film 2, and the plastic film 2 and the capacitor Since the overlapping films 2 are firmly bonded to each other by the element and winding, the insulating film 4 may peel off and burrs on the film may occur between the electrode formation process by spraying metallicon particles and the final packaging process. It is possible to prevent this from occurring, and as a result, as mentioned above, the appearance defect rate can be significantly reduced. It should be noted that, instead of using the plastic film 2 provided with the colored coating layer 3, it is possible to add a coloring agent in advance to the film 2 for coloring, which will of course make it easier to identify and remove metallicon particles. Coloring the film at the time of manufacturing increases the cost, has problems in terms of 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 this time, a non-adhesive resin can be used as the resin mixed with a coloring agent such as a dye or pigment to form the colored coating layer 3, and it can be adhered to the capacitor element 1 by applying an adhesive to the inner surface. Furthermore, 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 it can easily identify the adhered metallicon particles. 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 a capacitor element can be easily identified, thereby reducing insulation resistance defects and increasing reliability. It has the effect of improving sexuality.

[Brief explanation of the drawing]

The drawing is a perspective view of one embodiment of the invention. 1... Capacitor element, 1a... End face, 2...
Plastic film, 3... colored coating layer, 4... colored insulating film.

Claims (1)

[Scope of Claims] 1. A capacitor element in which a metallized film is wound or laminated, a colored insulating film in which a colored coating layer is formed on one or both sides of a plastic film to cover and protect the outermost periphery of the element, and A capacitor with electrodes formed of metallicon on the end face. 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 capacitor element, and the inner surface of the film is coated with a resin or glue containing a coloring agent. 3. The capacitor according to claim 2, wherein the resin or glue is non-tacky at room temperature and sticky at 60° C. or higher, and the colored insulating film is heat-sealed to the outer periphery of the capacitor element.