JP2735646B2 - Sealing body for electrolytic capacitor and method for manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a sealing body for an electrolytic capacitor, and more particularly, to a high gas impermeability and a paste infiltration by surface treatment of a sealing body carbon-based rubber sheet. The present invention relates to a sealing body for an electrolytic capacitor to which transparency and excellent chemical resistance are added, and a method for producing the same.

[Related Art] Electrolytic capacitors are small, large-capacity, inexpensive, and have excellent characteristics such as smoothing of rectified output. They are one of the important components of various electric and electronic devices. An aluminum film converted into an oxide film serving as a dielectric by oxidation is used as an anode, and an element composed of this and a current collecting cathode is impregnated with an electrolytic solution (paste) and sealed in a container.

Since an electrolytic capacitor is used while performing a chemical reaction for regenerating an oxide film, its characteristics most depend on the properties of an electrolytic solution to be used. As an electrolytic solution for an electrolytic capacitor, an electrolytic solution composed of ethylene glycol and boric acid is generally used. This type of electrolytic solution is an aqueous electrolytic solution that generates condensed water, and hydrates an oxide film dielectric. In recent years, non-aqueous electrolytes that do not substantially contain water tend to be used more and more because problems such as deterioration and occurrence of poor appearance of capacitors due to gasification of water during use at high temperatures occur.

The container for enclosing the element impregnated with the electrolytic solution includes a case having an opening at one end and made of a metal material such as aluminum, and a sealing body mainly made of bakelite. As the base material of the sealing body, bakelite is most commonly used from the viewpoints of structure retention characteristics, cost, and the like. In manufacturing, after the element impregnated with the electrolytic solution is put in the case, the sealing body is fitted and sealed in the opening of the case to assemble the electrolytic capacitor product. In order to ensure this fitting, a rubber sheet or the like is often interposed between the bakelite substrate and the opening.

In order to improve the performance of the electrolytic capacitor and expand the application, it is necessary to promote the active use of the non-aqueous electrolytic solution as described above. Even if the properties are improved by improving the electrolytic solution, the deterioration of the life characteristics due to the deterioration of the sealing body cannot be avoided from the viewpoint of the overall performance of the capacitor product.

There have been attempts to improve the sealing body of an electrolytic capacitor so as to realize a wider range of usable electrolytes. For example, Japanese Patent Publication No. 57-38182 discloses a thermocompression bonding of a vulcanized rubber sheet and a filled polypropylene plate containing a filler such as talc with a polyolefin-based hot melt film containing polypropylene or polyethylene as a main component. There is disclosed an electrolytic capacitor characterized by using a sealing plate joined by performing the above steps. In the same publication, column 2, line 34 to column 3, line 4, butyl rubber (IIR) is the most stable material, but there is concern about liberation of corrosive extracts. It is described that practical use as a sealing material has not progressed much. For this reason, in this technology, in order to achieve the purpose, studies are being made to obtain a sealing plate that does not corrode using ethylene propylene terpolymer (EPT) as the next best material.

On the other hand, in the manufacturing process of the electrolytic capacitor, after the element is put in a case and sealed with a sealing body, in order to give a clean appearance by cleaning dirt derived from paste and the like attached to the case and the like during the manufacturing, A step of cleaning using a cleaning agent such as chlorocene is indispensable. In this case, if the sealing by the sealing member is not reliable, the cleaning agent enters the inside of the electrolytic capacitor and causes deterioration of the product. From this point of view, the reliability of the sealing by the sealing member has a great influence on the product quality.

In order to obtain a suitable sealing body for electrolytic capacitors with a wide range of applications, comprehensive consideration should be given to the organic solvent resistance, chemical resistance, fit, and adhesion to the bake plate of the rubber sheet to be interposed. There is a need.

Rubber sheets such as IIR and EPT used for the sealing body for electrolytic capacitors have the properties as described above as a material, but in order to provide a suitable sealing body, not from the surface of the material, but for the electrolytic capacitor. It is considered that there is a means for improving the processing by paying attention to the processing that adds properties suitable for the sealing body. Conventionally, the sealing body has been improved by attaching a Teflon sheet or the like having good gas impermeability and chemical resistance to the surface of a rubber sheet. It can be said that the focus is on.

Butyl rubber (IIR) is considered to be the most stable as a sealing material from the viewpoint of material properties, but studies are being conducted to realize a truly effective sealing body for electrolytic capacitors without being bound by its material properties. As a result of stacking, by performing surface treatment of a carbon-based rubber sheet represented by IIR, it is possible to realize a sealing body for an electrolytic capacitor having high gas impermeability, paste impermeability, and excellent chemical resistance. Was found this time.

Thereby, it is expected that the above-mentioned problem such as release of the corrosive extract is also reduced at the same time.

[Problems to be Solved by the Invention] The present invention adds high gas impermeability and paste impermeability and excellent chemical resistance by surface treatment of a sealing carbon-based rubber sheet to prevent gas (paste) leakage. An object of the present invention is to provide a sealing body for an electrolytic capacitor which reduces the cleaning resistance, improves the washing resistance, and extends the life of the aluminum electrolytic capacitor, and a method for manufacturing the same.

[Means for Solving the Problems] According to the present invention, there is provided a sealing body for an electrolytic capacitor comprising a carbon-based rubber sheet, wherein one or both surfaces of the carbon-based rubber sheet are fluorinated by a fluorine-containing gas treatment. The present invention provides a sealing body for an electrolytic capacitor, characterized by having a thin film layer of polyfluorocarbon having low gas and paste permeability due to the above.

Furthermore, according to the present invention, when producing a sealing body for an electrolytic capacitor made of a carbon-based rubber sheet, the sealing body carbon-based rubber sheet press-formed is exposed to a fluorine-containing gas, and fluorinated by treating one or both surfaces. A method for producing a sealing body for an electrolytic capacitor, characterized in that a thin film layer of polyfluorocarbon having high gas and paste impermeability is formed.

It is preferable that the carbon-based rubber sheet is an IIR rubber sheet.

It is preferable that the fluorine-containing gas is a single gas of fluorine alone or a mixed gas of a single fluorine and a mixture of a gas selected from the group consisting of sulfur dioxide gas, oxygen gas and nitrogen gas.

The treatment with a fluorine-containing gas is preferably carried out at room temperature in a stainless steel container having a Teflon coating on the inside as shown in FIG. 1 at a total pressure of 0.05 to 5 kg / cm ² and a partial pressure of a fluorine-only gas. The processing is performed under the conditions of 0.001 to 1 kg / cm ² and the processing time of 1 to 120 minutes.

Using the sealing body for an electrolytic capacitor described above, the element impregnated with the paste can be sealed in a case by a normal manufacturing process to manufacture an electrolytic capacitor.

[Action] The present invention relates to an IIR or EPT used for a sealing body for electrolytic capacitors.
The present invention is not intended to improve the properties of the carbon-based rubber sheet as described above, but to improve the processing by adding a property suitable for a sealing body for an electrolytic capacitor.

That is, using a sealing body for an electrolytic capacitor made of a carbon-based rubber sheet, exposing the press-formed sealing body carbon-based rubber sheet to a fluorine-containing gas, and treating one or both surfaces thereof, a polyfluorinated material having high gas and paste impermeability. A thin film layer of carbon is formed on the surface of the rubber sheet, thereby suppressing gas (paste) permeation.

By using the carbon-based rubber sheet having been subjected to the surface treatment according to the present invention, the characteristics of the sealing body for the electrolytic capacitor are improved, gas (paste) hardly escapes in the electrolytic capacitor product, and the chemical resistance of the sealing body is reduced. As a result, the cleaning agent such as freon or chlorocene hardly enters the inside of the capacitor, so that the life of the aluminum electrolytic capacitor can be prolonged and the cleaning resistance can be improved.

[Effects of the Invention] According to the present invention, the surface treatment of the sealing body carbon-based rubber sheet adds high gas impermeability and paste impermeability and excellent chemical resistance, and reduces gas (paste) bleeding. The present invention provides a sealing body for an electrolytic capacitor, which improves washing resistance and extends the life of an aluminum electrolytic capacitor, and a method for manufacturing the same.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited only to the following examples.

Preparation of Sealing Body An IIR rubber sheet was placed in a stainless steel container whose inside was coated with Teflon as shown in FIG. 1, and at room temperature, the total pressure was 3 kg / cm ^2, and 2% F ₂ as a fluorine-containing gas was used. /
The treatment with a fluorine-containing gas was performed using a 98% N ₂ gas under a treatment condition of a treatment time of 20 minutes.

First, after placing the IIR rubber sheet sample 10 in the container 12, sealing the container and closing all the gas control valves 14, the three-way valve 16 is operated to cut off the communication with the outside air, and the container 12 And the vacuum pump 18 were connected. The fluorine single gas control valve 20 and the inert nitrogen gas control valve 22 are closed. After evacuating the container 12 by operating the vacuum pump 18, all the gas control valves 14 are opened, and while monitoring the pressure with the pressure gauge 24, the single fluorine gas control valve 20 and the inert nitrogen gas control valve 22 are adjusted. Then, a fluorine single gas and an inert nitrogen gas were introduced into the container until a predetermined pressure was reached. Thereafter, the sample 10 in the container was treated with a fluorine-containing gas under the above-described predetermined conditions.

Production of Electrolytic Capacitor Example 1 An electrolytic capacitor equipped with the sealing body produced as described above was produced. Using a γ-butyrolactone-based electrolytic solution as a paste, an electrolytic capacitor having a size of 6.3φ × 5 and a rating of 35V22 μF was produced by a conventional method.

FIG. 2 is a cross-sectional view of the electrolytic capacitor, and FIG. 3 is a cross-sectional view of the sealing body for an electrolytic capacitor according to the present invention. In the figure,
26 is an element, 28 is a case, 30 is a sealing body, 32 is a surface-treated carbon-based rubber sheet, 34 is a bake plate, 36 is a terminal, and 38 is a polyfluorocarbon layer.

Comparative Example 1 An electrolytic capacitor was produced in the same manner as in Example 1 except that a rubber sheet not subjected to a surface treatment was used.

Performance test For the electrolytic capacitor manufactured as described above, the capacitance (Ca
Change in p) and weight change due to paste omission (Δwt)
Was measured. FIG. 4 shows the test results for the change in the capacitance (Cap), and FIG. 5 shows the test results for the weight change (Δwt) due to the loss of the paste.

From these results, when using an organic solvent such as γ-butyrolactone as a component of the electrolytic solution, the sealed body for an electrolytic capacitor according to the present invention is an electrolytic capacitor represented by a change in capacitance and a change in weight due to paste removal. Is maintained for a long period of time, and the life can be extended.

[Brief description of the drawings]

FIG. 1 is a view showing an apparatus for processing a carbon-based rubber sheet according to the present invention, FIG. 2 is a sectional view of an electrolytic capacitor, FIG. 3 is a sectional view of a sealing body for an electrolytic capacitor according to the present invention, and FIG. FIG. 5 is a diagram showing a change in capacity, and FIG. 5 is a diagram showing a change in weight due to paste omission. 10 IIR rubber sheet sample 12 Container 14 Total gas control valve 16 Three-way valve 18 Vacuum pump 20 Single fluorine gas control valve 22 Inert nitrogen gas control valve 24 Pressure gauge, 26… Element 28… Case, 30… Sealing body 32… Surface-treated carbon-based rubber sheet 34… Bake plate, 36… Terminal 38… Polycarbonate layer

Claims (4)

(57) [Claims] 1. A sealing body for an electrolytic capacitor comprising a carbon-based rubber sheet, wherein one or both surfaces of the carbon-based rubber sheet are provided with polyfluorinated gas and paste having low permeability to gas and paste by fluorination by a fluorine-containing gas treatment. A sealing body for an electrolytic capacitor, comprising a carbon thin film layer. 2. The sealing body for an electrolytic capacitor according to claim 1, wherein the carbon-based rubber sheet is a butyl rubber sheet. 3. The sealing for an electrolytic capacitor according to claim 1, wherein the fluorine-containing gas is a single gas of fluorine alone or a mixed gas obtained by mixing simple fluorine with a gas selected from the group consisting of sulfur dioxide gas, oxygen gas and nitrogen gas. body. 4. When producing a sealing body for an electrolytic capacitor made of a carbon-based rubber sheet, the sealing-molded carbon-based rubber sheet press-molded is exposed to a fluorine-containing gas and treated on one or both sides to fluorinate the gas and gas. A method for producing a sealing body for an electrolytic capacitor, comprising forming a thin film layer of polyfluorocarbon having high paste impermeability.