JPH1174161A - Drive electrolyte of electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the drive electrolyte of an electrolytic capacitor from increasing in resistivity by a method, wherein higher dibasic acid or its ammonium salt and boric acid or its ammonium salt are dissolved into a solvent whose main component is ethylene glycol, and a specific wt.% specific polyethylene glycol diacrylate is added to the above mixture for the formation of the drive electrolyte. SOLUTION: Multivalent alcohol such as ethylene glycol or the like is used as a solvent, adipic acid, sebacic acid or its ammonium salt is used as a main solute, mannitol and orthophosphoric acid are used as an additive for the formation of electrolyte, ammonia water as as a pH adjustor is added to the electrolyte, and polyethylene glycol diacrylate represented by a formula is added to the above electrolyte. An amount of polyethylene glycol diacrylate added to the electrolyte ranges form 0.10 to 10 wt.%. As a result of this setup, an electrolyte of this constitution can be improved in withstand voltage without increasing resistivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electrolytic solution for driving an electrolytic capacitor (hereinafter referred to as an electrolytic solution), and more particularly to an electrolytic solution having improved withstand voltage.

[0002]

2. Description of the Related Art Conventionally, synthetic polymers such as polyethylene glycol and polyacrylate have been used in an electrolytic solution in which a higher dibasic acid or its ammonium salt, and boric acid or ammonium borate are dissolved in a solvent containing ethylene glycol as a main component. It has been known that the addition of the compound improves the withstand voltage. However, these synthetic polymers have a very low solubility in the above-mentioned solvents, and there is a problem that only a small amount can be dissolved.

[0003]

Polyethylene glycol having a relatively small degree of polymerization of 1000 or less has high solubility in an electrolytic solution, but has little effect on the improvement of withstand voltage. On the other hand, those having a degree of polymerization of 1000 or more have a large effect on the improvement of the withstand voltage, but are accompanied by a significant increase in the specific resistance. In addition, since polyacrylate has an action as an electrolyte, the withstand voltage can be improved without greatly increasing the specific resistance, but the solubility is very low in an electrolytic solution containing ethylene glycol as a main solvent, and a very small amount is used. Can only be added. The present invention is intended to improve the above-mentioned drawbacks and to provide an electrolytic solution that can improve the withstand voltage while suppressing the increase in the specific resistance of the electrolytic solution, and can also improve the solubility. is there.

[0004]

SUMMARY OF THE INVENTION According to the present invention, polyethylene glycol diacrylate does not hinder the movement of ions in an electrolytic solution and has a higher solubility in ethylene glycol than polyethylene glycol having a polymerization degree of 1000 or more and polyacrylate. The present invention has been made to solve the above-mentioned problem by applying the characteristics to an electrolytic solution. That is, polyethylene glycol diacrylate is obtained by dissolving a higher dibasic acid or its ammonium salt, and boric acid or its ammonium salt in a solvent containing ethylene glycol as a main component.

Embedded image Of 0.10 to 10.0 wt%.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in Chemical formula 2, polyethylene glycol diacrylate has a structure in which acrylic acid has two terminals at the end of polyethylene glycol, and the terminal acrylic acid acts as an electrolyte in an electrolytic solution. Since the polyethylene glycol portion in the molecule exhibits a withstand voltage effect, it is possible to improve the withstand voltage without increasing the specific resistance. In addition, it has high solubility in ethylene glycol and is effective.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete contents of the embodiments will be described below. The solvent is a polyhydric alcohol such as ethylene glycol,
Use of adipic acid, sebacic acid or its ammonium salt as the main solute, mannitol or orthophosphoric acid as an additive, and ammonia water added as a pH adjuster. As an example, polyethylene diacrylate and polyethylene glycol and polyacrylate as comparative examples were added as shown in Table 1, and a specific resistance of the sample was measured at 30 ° C. and a spark generation voltage at 85 ° C. was measured.

[0007]

[Table 1]

As shown in Comparative Examples 1 and 2 in Table 1, 0.1 wt% of polyethylene glycol having a polymerization degree of 1000 was used.
When added at 1.0 wt%, the spark voltage increases, but when the spark voltage is 415 V, the specific resistance increases to 730 Ω · cm, and when the spark voltage is 430 V, the specific resistance increases to 780 Ω · cm. At 10.0 wt%, it did not completely dissolve. Next, the result of study on the addition of polyacrylate is shown in Comparative Example 4, but even at 0.1 wt%, complete dissolution was not possible. Therefore, when polyethylene glycol diacrylate is added as shown in Examples 1 to 3, when the added amount is 1.0 wt%, the spark voltage becomes 430 V
And the specific resistance is suppressed to 720Ωcm, and 10.0wt%
Even when added, it was completely soluble, the spark voltage could be increased to 440 V, and the specific resistance could be suppressed to about 740 Ω · cm. At this time, if the added amount of polyethylene glycol diacrylate is less than 0.10 wt%, there is no effect of improving the withstand voltage, and if it exceeds 10.0 wt%,
The corrosion resistance to aluminum increases, and the withstand voltage decreases, which is unsuitable.

[0009]

As described above, polyethylene glycol diacrylate can be easily dissolved in an electrolyte mainly composed of ethylene glycol, and the withstand voltage can be improved without increasing the specific resistance. .

Claims (1)

[Claims] 1. A higher dibasic acid or an ammonium salt thereof, and a boric acid or an ammonium salt thereof are dissolved in a solvent containing ethylene glycol as a main component to obtain polyethylene glycol diacrylate. Of 0.10 to 10.0 wt% of an electrolytic solution for driving an electrolytic capacitor.