JP2003109881A - Sealer for electrolytic capacitor and method of manufacturing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealer for an electrolytic capacitor capable of maintaining good heat resistance and the longevity thereof even at high temperatures. SOLUTION: The sealer for the electrolytic 16 includes a polyphenylene sulfide film 2 which is bonded to an elastic rubber 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing body for an electrolytic capacitor, and more particularly to a sealing body for an electrolytic capacitor which has good heat resistance and physical properties by bonding a polyphenylene sulfide film to an elastic rubber.

[0002]

2. Description of the Related Art Electrolytic capacitors are small, have a large capacity, are inexpensive, and exhibit excellent characteristics for smoothing the rectified output.
It is one of the important constituents of electronic equipment. Generally, an aluminum film whose surface is changed into an oxide film as a dielectric by electrolytic oxidation is used as an anode, and an element composed of this and a collecting cathode is used as an electrolytic solution (paste). It is manufactured by impregnating the same in a container and enclosing it in a container.

The container for enclosing the element impregnated with the electrolytic solution is
It has an opening at one end and is composed of a case and a sealing body made of a metal material such as aluminum. In manufacturing, an electrolytic capacitor product is assembled by placing an element impregnated with an electrolytic solution in a case and then enclosing a sealing body in the case opening. As a conventional example, FIG. 5 is a cross-sectional view showing a configuration of an electrolytic capacitor 10, in which a capacitor element 12 in which an anode foil and a cathode foil are wound together with a separator is impregnated with an electrolytic solution, and the capacitor element is formed into a bottomed cylindrical shape. Outer case 14
And the open end of the outer case is sealed by the sealing body 16.

Among the parts of the electrolytic capacitor, the sealing body greatly affects the performance of the electrolytic capacitor, especially the deterioration and life of the electrolytic solution due to evaporation and diffusion of the electrolytic solution. Therefore, it is necessary to select an appropriate sealing body for the electrolytic solution. Is very important,
An elastic rubber is usually used as the sealing body.

[0005]

Conventionally, as a means for improving the problem, it has been dealt with by changing the kind and filling amount of the rubber filler. However, since the absolute level of properties largely depends on the molecular structure of the polymer, it has been difficult to make a breakthrough.

Further, as a conventional sealing rubber for an electrolytic capacitor which is required to have sealing property and heat resistance, isobutylene / isoprene / divinylbenzene (trade name: Bayer XL1), which is partially cross-linked butyl resin having good heat resistance to some extent, is used.
0000) Peroxide cross-linked butyl rubber of a terpolymer was used. However, the processability as a solid rubber is extremely poor, and the places where peroxide-crosslinked butyl using this polymer is produced are limited.

Further, Japanese Patent Application Laid-Open No. 7-307253 proposes a method of adhering a metal or resin to the surface of the sealing body to reduce the permeability of the electrolytic solution.

Further, Japanese Unexamined Patent Publication (Kokai) No. 8-306596 proposes an electrolytic capacitor in which a sealing member is made of a rubber composition and a resin material, and thereby has a small amount of permeation of an electrolytic solution and excellent alkali resistance.

On the other hand, in recent years, the guaranteed operating temperature of electrolytic capacitors used for automobile electrical components and inverter lighting is 15
The temperature has risen to 0 ° C.

However, in any of the above conventional sealing rubbers for electrolytic capacitors, high temperature use is limited to 125 ° C., and there is a problem that it cannot withstand particularly long time use at a high temperature such as 150 ° C. there were.

The present invention has been made in view of the above technical problems, and one of the objects of the present invention is that the heat resistance is better than that of the above-mentioned sealing body, and the life can be long even at high temperatures. An object is to provide a sealing body for an electrolytic capacitor and a manufacturing method thereof.

Still another object is to reduce the permeation of the electrolytic solution at the sealing site to prevent the performance deterioration of the electrolytic capacitor and to prevent the sealing body from contacting with the air to prevent cracking or hardening of the sealing body. An object is to provide a sealing body for an electrolytic capacitor that prevents it.

[0013]

In order to achieve the above object, a sealing body for an electrolytic capacitor according to the present invention is a sealing body used for sealing an electrolytic capacitor, in which a polyphenylene sulfide film is bonded to an elastic rubber. It is characterized by

Further, the polyphenylene sulfide film can be bonded to one side and both sides of the elastic rubber.

Further, the polyphenylene sulfide film is subjected to surface treatment by corona treatment and UV treatment, and when the elastic rubber is vulcanized and molded, a polyphenylene sulfide film is placed on the rubber so that the rubber is vulcanized and bonded at the same time. preferable.

Further, the polyphenylene sulfide film can be joined to the vulcanized elastic rubber by applying an adhesive agent after roughening sandpaper and surface treatment by plasma treatment.

At this time, the adhesive is selected from epoxy type adhesives, cyanoacrylate type adhesives, silicone type adhesives, polyimide type adhesives and silane coupling agents.

The elastic rubber is preferably a resin-vulcanized butyl rubber.

Further, there is provided a method of manufacturing a sealing body for an electrolytic capacitor, in which a polyphenylene sulfide film is bonded to rubber.

As the production method of the present invention, one is to subject a polyphenylene sulfide film to a surface treatment by corona treatment and UV treatment, and place the polyphenylene sulfide film on the rubber during vulcanization molding of an elastic rubber, Provided is a method for producing a sealing body by performing vulcanization molding and joining at the same time.

Further, as a further method, the polyphenylene sulfide film is subjected to surface treatment by sandpaper roughening and plasma treatment and then applied with an adhesive to bond with the vulcanized elastic rubber. Thus, the sealing body for an electrolytic capacitor of the present invention can be manufactured.

With the above constitution, the physical properties of the sealing body are improved, the heat resistance is good, and it becomes possible to have a long life even at high temperature.
Further, it becomes possible to reduce the permeability of the electrolytic solution to prevent the performance deterioration of the electrolytic capacitor and prevent the sealing body from cracking or hardening.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

The electrolytic capacitor sealing body according to the present invention comprises:
A polyphenylene sulfide film is bonded to elastic rubber.

The polyphenylene sulfide film is
It is a crystalline biaxially oriented film having about 40% crystallization, which is produced by a melt extrusion / biaxially stretched film forming method. This material, polyphenylene sulfide, is a polymer consisting of simple repeating benzene rings and sulfur atoms, and has excellent properties such as super heat resistance, flame retardancy, chemical resistance, and electrical properties. The polyphenylene sulfide film has mechanical properties such as tensile properties and viscoelasticity comparable to those of polyester films, and can be manufactured into a film having a thickness of 1.5 to 350 μm. Furthermore, it is excellent in heat resistance and can be used up to 160 to 200 ° C in the long term and up to 230 to 260 ° C in the short term. Furthermore, the phenomenon of cracking that occurs in other amorphous polymer films such as polyetherimide films does not occur. Furthermore, it has excellent hygroscopic properties and hydrolysis resistance, and does not show deterioration in high temperature steam unlike polyester films and polyimide films. Also, it has excellent chemical properties and has excellent chemical resistance as compared with polyester and polyimide. Furthermore, it has excellent electric characteristics, exhibits temperature and frequency characteristics, and maintains a low dielectric loss as compared with a polyester film up to a high temperature. This film may be configured alone or as a three-layer composite film in which another film, for example, a polyester film is inserted. The polyphenylene sulfide film can be surface-treated by sandpaper roughening, corona treatment, UV treatment, plasma treatment or the like. When joining the elastic rubber and the polyphenylene sulfide film, the polyphenylene sulfide film is subjected to the corona treatment or U
It can be joined by vulcanization molding after surface treatment by V treatment. In addition, the polyphenylene sulfide film surface-treated by sandpaper roughening and plasma treatment can be bonded to the elastic rubber by applying an adhesive. As a specific example of this adhesive,
Epoxy, cyanoacrylate, silicone, and polyimide adhesives are commonly used. Further, silane coupling agents such as vinyl, epoxy, methacryl and mercapto are also effective.

The elastic rubber according to the present invention may be a rubber material used for a conventional sealing body, such as ethylene propylene diene rubber capable of organic peroxide vulcanization, partially crosslinked butyl rubber,
Composed of either resin vulcanized butyl rubber.

The sealing body of the present invention seals an electrolytic capacitor (FIG. 4), and its structure is shown in FIG.
Various structures 16 as shown in are possible. In FIG. 1, the elastic rubber is 1, and the polyphenylene sulfide film is 2. Thus, the polyphenylene sulfide film 2 can be adhered to one side and both sides of the elastic rubber 1. Further, the thicker the polyphenylene sulfide film is, the more the deterioration of the rubber is suppressed. However, the thickness of the polyphenylene sulfide film is preferably 25 to 100 μm.

Further, in order to produce the sealing body of the present invention, for example, for a polyphenylene sulfide film,
Surface treatment is performed by corona treatment and UV treatment, and the polyphenylene sulfide film is placed during vulcanization molding of the elastic rubber, and the rubber is vulcanized and bonded at the same time. The surface treatment by the UV treatment is preferably 4
0 seconds.

Further, in the production method of the present invention, when the rubber after vulcanization is joined, the adhesive is applied to the polyphenylene sulfide film after the surface treatment by sandpaper roughening or plasma treatment. It can also be bonded to a polyphenylene sulfide film.

[0030]

EXAMPLES The present invention will be described below in detail based on examples, but the present invention is not limited to these examples. The components blended in the following examples and comparative examples are as follows.

[Example 1] 40 with respect to a polyphenylene sulfide film having a thickness of 38 µ (Torelina made by Toray)
After surface treatment by UV treatment for irradiation for 2 seconds, the polyphenylene sulfide film was placed on one side of the resin vulcanized butyl rubber, and the rubber was vulcanized and molded and simultaneously joined to produce a sealing body (for Φ8 product). .

Example 2 A sealing body (for a Φ8 product) was produced under the same conditions as in Example 1 except that the thickness of the polyphenylene sulfide film of Example 1 was 100 μm.

[Comparative Example 1] A sealing body made of a rubber of a resin vulcanized butyl rubber not bonded to a polyphenylene sulfide film was prepared by a conventional method.

Heat Aging Test The sealing bodies of Examples 1 and 2 and Comparative Example 1 described above were JIS K
According to 6257, by air heating aging test (normal oven method), after leaving in the oven at 150 ° C. for a certain time,
The products of Examples 1 and 2 were disassembled, the film was peeled off from the rubber surface, and the hardness of the surface was measured. FIG. 2 shows the change in hardness over time. The change in hardness of Example 1 shows a plot of {circle around (1)}, Example 2 shows a plot of [▲], and Comparative Example 1 shows a plot of ●.

From these results, in Comparative Example 1 in which no film was attached, cracking occurred at high temperature for a long time, but in Examples 1 and 2, stable hardness was preserved. Further, Example 2 in which the film was thicker had less change in hardness than Example 1 and retained more stable physical properties.

Example 3 The polyphenylene sulfide film of Example 1 was placed on both sides of a resin vulcanized butyl rubber,
A sealing body was produced under the same conditions as in Example 1 except for the above.

[Comparative Example 2] An adhesive (Chemlog, manufactured by Road Corporation, USA) was applied to Teflon (manufactured by Nitto Denko Corporation) having a thickness of 500 µ, and then bonded to one surface of a peroxide-vulcanized butyl rubber. Then, a sealed body was produced.

GBL Permeation Test As a result of measuring the permeation amount of the γ-butyrolactone (GBL) -based electrolytic solution with respect to each of the sealing bodies of Examples 1 and 3 and Comparative Examples 1 and 2 described above, the results are shown. Is shown in FIG.
Here, the test conditions are both 105 ° C. and 2000 hours. The GBL permeation amount change of the sealing body of Example 1 shows a plot of (1), and Example 3 shows a plot of (). Comparative Example 1 shows a plot of ●, and Comparative Example 2 shows a plot of ○.

As is clear from FIG. 2, the γ-butyrolactone (in the examples 1 and 3 which are the sealing bodies to which the polyphenylene sulfide film is bonded are more than the sealing body made of the rubber alone in the comparative example 1). GBL) has an advantage that the amount of permeation of the electrolytic solution is small and the life can be extended. Further, it was also found that the amount of permeation in Example 3 in which both surfaces were bonded was smaller than that in Example 1 in which the polyphenylene sulfide film was bonded to the rubber on one surface.

Further, in Comparative Example 2 in which Teflon (registered trademark) is adhered to rubber as a typical example of a fluororesin known to be excellent in heat resistance, chemical resistance, electric insulation, etc. The same GB as in Example 3 in which a 38 μm thick polyphenylene sulfide film was bonded to both sides of rubber.
It can be seen that a thickness of as much as 500μ is required to have the effect of L electrolyte permeation.

Example 4 A sealed body was prepared in the same manner as in Example 1 except that the UV irradiation time was 20 seconds in Example 1.

Comparative Example 3 A 38 μm-thick polyphenylene sulfide film (Torelina made by Toray) was bonded to one side of a peroxide-cured butyl rubber by UV treatment. U
The V treatment conditions were as follows: UV intensity was about 98 mW / cm 2, irradiation distance was about 80 mm, and irradiation was performed for 40 seconds with a lamp of 800 W low-pressure mercury lamp to produce a sealed body.

[Comparative Example 4] In Comparative Example 3, the UV treatment time was 20 seconds, and the others were the same as in Comparative Example 3 to produce a sealing body.

Adhesion Evaluation Test For Examples 1 and 4 and Comparative Examples 3 and 4, JIS K6
Table 1 shows the results of the tensile shearing adhesive strength test conducted using 256 standard strip-shaped test pieces.

[0045]

[Table 1]

From Table 1, Example 1 in which the UV treatment time was 40 seconds
The adhesive strength of Comparative Example 3 was higher than that of Example 4 and Comparative Example 4 in which the UV treatment time was 20 seconds. From this result, it was found that when the sealing body of the present invention is manufactured, the UV treatment time of 40 seconds is more suitable than the 20 seconds in terms of adhesive strength.

[0047]

As described above, according to the present invention,
A sealing body for an electrolytic capacitor, in which a polyphenylene sulfide film is bonded to an elastic rubber,
Under the condition of high temperature of 150 ° C. and long time, the heat aging property and high temperature life property can be significantly improved. Further, the permeability of the electrolytic solution can be reduced to prevent the performance deterioration of the electrolytic capacitor, and the sealing body from being cracked or hardened. Further, in order to obtain the effect, the sealing body for joining the films in the present application can be made thinner than the case where other resin materials are laminated, so that the electrolytic capacitor can be downsized.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a sealing body for an electrolytic capacitor according to the present invention.

FIG. 2 is a graph showing changes in rubber hardness over time in a 150 ° C. heat aging test of Examples and Comparative Examples of the electrolytic capacitor sealing body according to the present invention.

FIG. 3 is a graph showing changes in the permeation amount of the electrolytic solution at 1050 ° C. in Examples and Comparative Examples of the electrolytic capacitor sealing body according to the present invention.

FIG. 4 is a schematic cross-sectional view of an electrolytic capacitor using the electrolytic capacitor sealing body according to the present invention.

FIG. 5 is a schematic cross-sectional view showing the configuration of a conventional electrolytic capacitor.

[Explanation of symbols]

1 elastic rubber 2 Polyphenylene sulfide film 10 Electrolytic capacitor 12 Capacitor element 14 Outer case 16 Sealed body

Claims (8)

[Claims] 1. A sealing body for use in sealing an electrolytic capacitor, wherein a polyphenylene sulfide film is bonded to an elastic rubber forming the sealing body. 2. The polyphenylene sulfide film is subjected to surface treatment by corona treatment or UV treatment, the polyphenylene sulfide film is placed on the rubber at the time of vulcanization molding of an elastic rubber, and the rubber is vulcanized at the same time as bonding. Item 1. A sealing body for an electrolytic capacitor according to Item 1. 3. The polyphenylene sulfide film is bonded to an elastic rubber after vulcanization by applying an adhesive after surface treatment by sandpaper roughening or plasma treatment.
The sealing body for the electrolytic capacitor described. 4. The sealing body for an electrolytic capacitor according to claim 1, wherein the elastic rubber is a resin-vulcanized butyl rubber. 5. The sealing body for an electrolytic capacitor according to claim 3, wherein the adhesive is an epoxy-based adhesive, a cyanoacrylate-based adhesive, a silicone-based adhesive, a polyimide-based adhesive or a silane coupling agent. 6. A method for producing a sealing body for an electrolytic capacitor, in which a polyphenylene sulfide film is bonded to elastic rubber. 7. The polyphenylene sulfide film is subjected to surface treatment by corona treatment or UV treatment, a polyphenylene sulfide film is placed on the elastic rubber at the time of vulcanization molding, and the rubber is vulcanized and bonded at the same time. 6. The method for manufacturing the sealing body for an electrolytic capacitor according to 6. 8. The polyphenylene sulfide film is bonded to an elastic rubber after vulcanization by applying an adhesive after surface treatment by sandpaper roughening or plasma treatment.
A method for producing a sealing body for an electrolytic capacitor as described above.