JPH02101726A - Separator for electrolytic capacitor - Google Patents

Abstract

PURPOSE:To obtain an electrolytic capacitor that is low in equivalent series resistance value or excellent in sound quality by making it contain fibers at least partly consisting of animal protein. CONSTITUTION:This contains fibers consisting of animal protein. These fibers relate to artificial protein fibers made of protein such as milk, casein, etc., and for example polymerized mixture, which is obtained by dissolving protein in thick aqueous solution of proper inorganic salt together with the monomer of acrylonitrile and adding radical polymerization catalyst to it and polymerizing acrylonitrile, becomes fiber raw material, and this is obtained as fibers by wet spinning. The thickness of one fiber is enough thinner than Manila hemp, and those are obtained as paper by cutting, beating, paper making, etc. As the paper made of this protein fiber is close, the maintenance amount of electrolyte improve, and electrical resistance value when electrolyte is impregnated can be made small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a separator in an electrolytic capacitor in which an anode foil and a cathode foil made of aluminum foil or the like are laminated or wound with a separator in between.

[Prior Art] Generally, an aluminum electrolytic capacitor is manufactured by laminating an anode foil and a cathode foil made of aluminum foil with a separator in between, or by impregnating a wound capacitor element with an electrolytic solution and assembling it together with a sealing body in an exterior case. It has an intricate structure.

In such laminated or wound type electrolytic capacitors, a separator is used to retain a sufficient amount of electrolyte and to prevent short circuits between the electrodes. The material for manufacturing the separator is vegetable fiber or synthetic resin fiber.

Most separators made of vegetable fibers are kraft paper or Manila hemp paper. In addition, small amounts of products made from Indian solar sieve and cotton are also used.

Although kraft paper is cheap and strong, it has the disadvantage that the fibers are flat, so the current path after being impregnated with electrolyte becomes long and the electrical resistance increases. Manila hemp paper has the advantage of lower resistance than kraft paper because the fiber shape is somewhat circular and the current path is shorter. Papers made from a mixture of kraft and manila hemp are also used.

Materials for separators made of synthetic fibers include polypropylene, vinylon, rayon, polyethylene, and polyester. Such synthetic fibers can be obtained in a shape close to a perfect circle, so they can have a low resistance value after being impregnated with an electrolyte, but they have the disadvantage that it is difficult to obtain a material with good properties as paper. It is often used as a mixed paper with kraft or manila hemp.

[Problems sought to be solved by the invention] Electrolytic capacitors using separators as described above still have a high resistance value and hold a small amount of electrolyte (
When viewed as an electrolytic capacitor, it has a high electrical resistance value at room temperature and low temperature, which causes problems when used in switching power supplies. In addition, when electrolytic capacitors are used as power supply smoothing capacitors or coupling capacitors for audio equipment, they have a high resistance value with respect to frequency, and are difficult to absorb internal and external vibrations.
It has become difficult to prevent audio signal deterioration and sound quality distortion.

[Means for Solving the Problems] However, in order to solve the above-mentioned problems, the present invention provides a separator containing fibers made of animal protein.

The fibers made of animal protein used as the material constituting the separator of the present invention refer to artificial protein fibers made from proteins such as milk casein. A polymerization mixture obtained by dissolving acrylonitrile in a concentrated aqueous solution and adding a radical polymerization catalyst thereto and polymerizing acrylonitrile becomes a fiber raw material, which is obtained as a fiber by wet spinning. The polymerization mixture that becomes the fiber raw material is a protein, a graft polymer of acrylonitrile to protein, and a homopolymer of acrylonitrile.
Consists of ingredients. Incidentally, it is preferable that protein and acrylonitrile are copolymerized at a ratio of about 3 Nia. Such milk casein fiber is called Promix and is already commercially available. Moreover, instead of acrylonitrile, a promix can also be obtained by copolymerizing a protein with a vinyl monomer such as acrylic ester, acrylic amide, vinyl acetate, or vinyl pyridine.

Artificial protein fibers made from animal protein have a single fiber thickness that is much thinner than Manila hemp.
This is obtained as paper by cutting, beating, paper making, etc. Since paper made from protein fibers is dense, the amount of electrolyte retained can be improved, and the electrical resistance value when impregnated with electrolyte can be reduced. Also,
In order to strengthen the mechanical strength, when made as a mixed paper by incorporating vegetable fibers such as manila hemp and kraft,
The protein fibers are tightly entangled in the gaps between the thick fibers of Manila hemp and kraft, forming extremely thin gaps, which improves the withstand voltage of the electrolytic paper separator. It was also found that the electrical resistance value when impregnated with electrolyte was significantly smaller than that of Manila hemp or kraft alone. In addition, according to separators containing protein fibers, the separators are soft and have little repulsive force against minute bending forces caused by vibrations, and therefore can prevent audio signal deterioration and sound quality distortion. be.

The separator according to the present invention is made of protein fibers alone, or mixed with other vegetable fibers, synthetic resin fibers, glass fibers, or mixed fibers thereof.

Next, a paper made only of the above milk casein fibers and a mixed paper made of the above milk casein fibers and manila hemp were respectively prepared, and γ-butyrolactone, ethylene glycol, acetonitrile, N- Although the paper was immersed in N dimethylformamide, ethylene glycol monomethyl ether, and diethylene glycol monomethyl ether solutions for a long time, no changes such as discoloration or deterioration were observed in either paper.

However, deterioration was observed in the caustic soda solution.

[Example] Example 1 A separator made of 70% milk casein fiber and 30% Manila hemp, thickness 60LLm, density 0.5g/cm
The airtightness of this separator is 20.
ES at 20°C and 1kHz when impregnated with γ-butyrolactone electrolyte.
R was 0.67Ω.

Reference example: Manila hemp alone separator, thickness 60μm, density 0
．． A sample with a weight of 5 g/cm3 was prepared. The airtightness of this separator is 10.5 sec 7100 cc, and when impregnated with γ-butyrolactone electrolyte, it is heated at 20°C and 1 kHz.
The ESR of z was 0.75Ω.

Next, an aluminum electrolytic capacitor with a rating of 63 V and a capacity of 470 μF was prepared using the above-mentioned separator, and the frequency characteristics of the equivalent series resistance (ESR) at 20° C. were measured.

The results are shown in Table 1.

Table 1 Frequency characteristics When we investigated the 3rd harmonic distortion rate when a 10kHz signal was input when 1kHz vibration was applied to these electrolytic capacitors, we found that those of Example 1 were superior to those of the reference example. ,
It was found that the reduction was 4 to 5 dB.

In addition, when these electrolytic capacitors were used in the coupling circuit of a CD player and listened to with different attachments, it was found that the distortion in high-frequency sound quality was significantly reduced in the case of Example 1 compared to the case of the reference example. The amount of information in the sound was significantly increased, resulting in a well-balanced and high-quality sound. [Effect] As mentioned above, according to the separator of the present invention containing at least a portion of protein fibers, the equivalent series resistance value We can provide electrolytic capacitors with low sound quality and electrolytic capacitors with good sound quality.

In addition to aluminum electrolytic capacitors, the separator according to the present invention can also be used for energy storage devices such as electric double layer capacitors, solid electrolytic capacitors, other special capacitors, secondary batteries, secondary batteries, and other special batteries. Can be applied as a separator.

Claims (2)

[Claims] (1) A separator for an electrolytic capacitor containing at least a portion of fibers made of animal protein. (2) The separator for an electrolytic capacitor according to claim (1), wherein the fiber made of animal protein is milk casein fiber.