JPS58180011A - Method of sheathing 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 The present invention relates to a method of packaging a non-inductive structure capacitor.

Capacitor packaging methods include metal or nonmetallic cases or nonmetallic packaging. Non-metallic exteriors include methods such as resin dipping, powder coating, casting, and insulating tape wrapping with Ushitake Endonol. The purpose of encasing a 1° capacitor is to insulate it from the outside and sufficiently block the outside air, which is currently the most economical way to manufacture capacitors by combining various factors such as equipment, material cost, and workability. This ensures that the insulation is completely protected. On the other hand, if the external insulating material adheres to the terminal, accidents such as poor contact may occur when connecting to an external circuit. That is, it is necessary for the exterior to have no resin or the like attached to the terminal portion, and for the resin to be attached uniformly to the element. To explain the dipping method that is most commonly used at present, the capacitor element is added to a liquid resin that is made by adding adhesive particles to epoxy resin or unsaturated polyester resin to give it tackiness. y3
L. Then, when it is gently pulled up, the tree adheres to the entire surface of the element for 111 kalpas. Terminal areas where you want to avoid resin adhesion, usually lead
1. If the wire lead-out part is immersed in uncured resin liquid or there is a risk of resin liquid adhering to it, cover it with non-adhesive resin such as adhesive resin or fluororesin beforehand. By applying the resin to the area, it is possible to prevent the resin 7' from getting wet.

, l'j There is no problem with the above dipping method for a capacitor with an inductive structure where the outside of the element shown in Figure 2 is made of an insulating material and has no metal parts or corners on the side, but the element shown in Figure 4 has no problem with the dipping method described above. It is difficult to form a uniform coating on capacitors with a non-inductive structure, such as metallized film capacitors, which have metal parts serving as electrodes on the outside and have corners and protrusions.

To explain with reference to the drawings, FIG. 1 is an external view of a film capacitor having an inductive structure, and FIG. 2 is a cross-sectional view taken along the line A--A. Reference numeral 1 denotes an element in which a film and an electrode are overlapped and rolled up, and the outside is made of an insulating film. 2 is a lead wire, and 3 is a dipped resin. Since there are no corners on the outside of the element 1, the resin adheres almost uniformly around the element.

FIG. 3 is an external view of a non-inductive metallized film capacitor, and FIG. 4 is a cross-sectional view taken along the line A--A. 4 is a metallized film, 5 is a metal sprayed with zinc, solder, or the like using metallicon, 6 is a lead wire, and 7 is a resin that has been debossed. On the outside of the element, there is metal such as metal contactor and lead wire 6, and there are also corner parts as shown in B. Therefore, the corner part B of the resin becomes extremely thin compared to the flat part C,
For example, while the thickness of the flat portion C is 0.2+mm, the thickness of the corner portion is less than 0.1 mm, and insulation from the outside is incomplete.

If this dip-dip resin is applied thickly, the resin will sag at the bottom and spoil the appearance, so by repeating dipping and heat curing several times, it is possible to reduce the sagging and perfect the insulation from the outside. It has the drawbacks of being large in size and requiring a lot of man-hours. Among various features, the powder coating method has the advantage that even corners and protrusions can be coated very well and no sagging occurs. On the other hand, it has the disadvantage that it cannot be applied thinly to cover the entire surface. Powder coating Yuyori-C coating JゎE non-inductive structure I 77'/month.

An external view is shown in Figure 5. FIG. 6 is a sectional view taken along the line A-A. The corner B is covered with powder resin to approximately the same thickness as the other parts, and can be completely insulated from the outside.

Another drawback when applying powder coating to a capacitor is that resin adheres to the lead-out portion of the lead wire. To coat the part between the leads of the capacitor element, part D in FIG. 5, part D must be immersed in the powder fluidized bed. 1 to 3 times from the top of the element, depending on the thickness of the element
It is necessary to deeply immerse the powder in a fluidized powder bath. As shown in the external view of FIG. 5, the completed capacitor has excess resin 8 attached to the lead-out portion of the lead wire 6.

In the case of powder coating, unlike liquid resin dipping, it is not possible to prevent resin from adhering even if a non-adhesive resin such as silicone resin or fluororesin is applied to the lead wire lead-out portion in advance. If resin 8 is attached to the lead wire lead-out part, when attaching the capacitor to the printed circuit board, the resin 8 may enter the hole in the board and the soldering may be incomplete, or the capacitor may be printed to ensure perfect soldering. This causes inconveniences such as requiring extra space because it is mounted at a distance from the substrate.

The present invention is a capacitor exterior packaging method that takes advantage of the advantages of powder coating and liquid resin dipping, and will be explained in detail below.

Preheat a non-inductive capacitor element whose lead wires are coated with a very thin layer of non-adhesive resin such as silicone resin, plastic resin, etc., and place it in a powder fluidization tank to the extent that the element is almost immersed. Perform all powder coating. Thereafter, the powder-coated capacitor element is placed in a liquid resin dipping tank until it is completely immersed, and after being gently pulled out of the tank, it is heated and cured.

FIG. 7 shows an external view of a non-inductive structure capacitor equipped with an exterior according to the present invention, and FIG. 8 shows a sectional view taken along the line 8-A.

Since the lead wire extraction portion is not immersed in the powder resin tank, powder resin does not adhere to it. In addition, almost no powder resin is applied to the seventh cut portion. Metallicon 5 and lead wire 6 in Fig. 8
The metal parts, including corners and protrusions, are coated with powdered resin.

Since heat inside the element is conducted to the metal part and transferred to the surface, the powder resin tends to adhere to the metal part more thickly than the insulating part. The above trend is a useful effect for non-inductive structure capacitors since the metal parts of the device are required to be insulated from the outside. Since the liquid resin dip is applied on top of the powder coating, it has better adhesion on the metal parts than dipping directly onto the element, and is applied evenly over the entire surface.

Since the liquid resin is applied uniformly, the resin can be applied thinly, resulting in less dripping. During the liquid resin dipping process, when the device is pulled up from the liquid resin dipping tank and heat cured, if the lead wires are placed downwards and heat cured, the liquid resin tends to be applied a little thickly to the seventh dipping area. Therefore, the total resin thickness in the D part, where powder coating is hardly applied, is almost the same as the other parts, improving the uniformity of the overall thickness of the exterior resin layer. I can do it.

The thickness of the exterior resin of a non-inductive structure capacitor varies depending on the size of the element, the type of resin, and working conditions, but an example for comparison is as follows. In the case of only liquid resin dip, it is about 0.4 m, in the case of powder coating only, about 0.4 + nM, and in the case of the present invention, about 0.3 m, and the powder coating and liquid resin dip are each about 0.15 m. The result of packaging according to the present invention will be explained with reference to FIG. 8. In the device, the outer metallic compound 5 and the 1,1-wire 6, including the corners and protrusions, are covered with a powdered resin 10, and the outside is covered with a liquid resin. After being dipped in resin, it is covered with thermoset resin 11 and is completely insulated from the outside.

The element is impregnated with filler-free liquid resin under reduced pressure in order to completely protect the insulation by isolating the capacitor from the outside air and to prevent pinholes from forming on the exterior surface due to air bubbles from inside the element. A so-called undercoat, which is then thermally cured, may be applied. Since the thickness of the resin applied to the surface by undercoating is 0.1 mm or less, when powder coating is applied on top of this, there is no change in the tendency for the powder resin to be applied thickly to the metal parts. Therefore, there is also a method of applying the powder coating of the present invention and liquid resin dip after undercoating. In this case, the process can serve as both the thermal curing of the undercoat and the preheating of the powder coating.

A 1 μF metallized film capacitor element was fabricated using a metalized film made by vapor-depositing aluminum on a 3 μ polyethylene terephthalate film, and after applying an undercoat, 1000 pieces of each were manufactured using liquid resin dipping, powder coating, and each method of the present invention. did. The thickness of the exterior resin is about 0.3 mm in the case of the present invention, and about 0.4 mm in the other two cases. In the case of liquid resin dip, there were 34 appearance defects, and the majority of the defects were due to dimensional defects due to sagging. In the case of powder coating, there were 76 defects in appearance, and most of the defects were caused by pinholes. In the case of the present invention, the appearance defects were only three pinhole defects. In addition, 10 pieces of each were sampled and subjected to a 1,000-hour humidity test at a temperature of 40° C. and a relative humidity of 95%. As a result, the resistance of all samples was 30,000 MΩ or more, and excellent results regarding 1Ijt humidity were obtained.

As described above, according to the present invention, the exterior of a capacitor with stable quality and non-inductive structure can be manufactured economically with little dripping.

[Brief explanation of the drawing]

The figures are only for explaining the present invention; Fig. 1 is an external view of a conventional inductive structure capacitor, Fig. 2 is a sectional view thereof, and Fig. 3 is a sectional view of the conventional inductive structure capacitor.
The figure is an external view of a non-inductive structure capacitor coated with a conventional liquid resin dip, FIG. 4 is a cross-sectional view thereof, and FIG. FIG. 6 is a sectional view thereof, FIG. 7 is an external view of a non-inductive structure capacitor according to the present invention, and FIG. 8 is a sectional view thereof. Patent applicant: Towa Electric Co., Ltd. Figure 2 Figure 4

Claims (1)

[Claims] After applying non-adhesive resin to the lead wire of a capacitor with a non-inductive structure, powder coating is applied, and then liquid resin is applied again.
Method for packaging a capacitor characterized by coating 1.