JP2960153B2 - Electrolyte for driving electrolytic capacitors - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic solution for driving a high-pressure aluminum electrolytic capacitor (hereinafter referred to as an electrolytic solution) that enables cleaning of an aluminum electrolytic capacitor up to 450 WV with a halogenated hydrocarbon. Things.

2. Description of the Related Art Conventionally, as an electrolytic solution for a high-voltage electrolytic capacitor, an electrolytic solution containing ethylene glycol as a main solvent and dissolving boric acid and an organic acid or a salt thereof has been used. Also, there is an increasing demand for cleaning with halogenated hydrocarbons. Therefore, for the purpose of preventing corrosion of the capacitor element,
Measures have been considered by adding nitro compounds to these electrolytes.However, with nitrobenzoic acid or nitrophenol, which is usually used for low-pressure electrolytes, the withstand voltage is significantly reduced. Nitroanisole and nitrophenetol are known as nitro compounds that can be used for high-voltage applications. However, application of these high-voltage electrolytic capacitors to electrolytes is not possible due to problems in withstand voltage and reliability. Nitro compounds that can be used as electrolytes for electrolytic capacitors have not yet been put to practical use.

Problems to be Solved by the Invention When an electrolytic capacitor is mounted on a printed circuit board by soldering, in a step of removing solder flux in the process,
By immersion in a halogenated hydrocarbon used as a cleaning agent or by a steam bath, the halogenated hydrocarbon penetrates through the sealing material of the electrolytic capacitor and enters the inside of the capacitor, decomposes and generates chlorine ions. Since chlorine ions could corrode the capacitor element,
Nitrobenzoic acid or nitrophenol was added to prevent corrosion by halogenated hydrocarbons.
Their addition has been limited to low pressure applications (mainly 100 WV or less) because of their lower withstand voltage.

Therefore, nitroanisole, nitrophenetol, etc. have been studied as nitro compounds that do not lower the withstand voltage even when added to the electrolytic solution for medium pressure electrolytic capacitors.
The application up to 0 WV is the limit, and nitroanisole or nitrophenetol has low thermal stability, and gradually changes to nitrophenol by cleavage of the ether bond, so it depends on withstand voltage and halogenated hydrocarbon. There was a problem that the ability to prevent corrosion was reduced.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides nitroacetophenone, nitrobenzamide in an electrolyte obtained by dissolving boric acid or a salt thereof and an organic acid or a salt thereof with ethylene glycol as a main solvent. 0.1 wt% of at least one of
An electrolytic solution for driving an electrolytic capacitor, characterized in that it is added in an amount of less than 0.5 wt%.

The nitroacetophenone is O-nitroacetophenone, m-nitroacetophenone, or P-nitroacetophenone, and the nitrobenzamide is O-nitrobenzamide, m-nitrobenzamide, or P-nitrobenzamide.

The electrolytic solution according to the present invention suppresses the release of chloride ions even when halogenated hydrocarbons used as a cleaning agent enter the capacitor case in a high-pressure aluminum electrolytic capacitor, and has thermal stability. Since it is high, there is no decrease in withstand voltage and ability to suppress chloride ion release.

Examples Hereinafter, examples of the present invention will be described.

Table 1 shows a comparative example of the composition, specific resistance and spark generation voltage of the electrolytic solution of the present invention and the conventional electrolytic solution. In Table 1, electrolyte sample symbols A, B, C, and D are conventional examples, and E is an example of the present invention.

As is clear from Table 1, the sample symbol E according to the present invention was used.
No decrease in the withstand voltage is observed in the electrolytic solution of the present invention as compared with the conventional voltage solution.

Table 2 shows the ratings made using the electrolyte shown in Table 1.
The results obtained by immersing a 450WV22uF aluminum electrolytic capacitor in 1,1,1-trichloroethane for 5 minutes and then performing a high-temperature load test at 105 ° C. for 5000 hours are shown.

As is clear from Table 2, the sample symbol E according to the present invention was used.
The electrolytic capacitor using the electrolytic solution of the above does not decrease the ability to suppress the release of chlorine ions from halogenated hydrocarbons even in a test in a high temperature atmosphere for a long time,
It was not possible with an electrolytic capacitor using a conventional electrolytic solution. It is possible to clean electrolytic capacitors up to a rated voltage of 450 WV with halogenated hydrocarbons.

Effect of the Invention As described above, one or more of nitroacetophenone and nitrobenzamide are added to an electrolytic solution obtained by dissolving boric acid or a salt thereof and an organic acid or a salt thereof using the ethylene glycol of the present invention as a main solvent, and adding 0.1 or more of the same. Aluminum electrolytic capacitors using an electrolytic solution characterized by being added in an amount of not less than 0.5% by weight and less than 0.5% by weight enable cleaning of aluminum electrolytic capacitors up to 450 WV with halogenated hydrocarbons,
In addition, since the thermal stability is high, there is no thermal deterioration of the chloride ion release inhibitor, so that it is possible to maintain excellent characteristics over a wide temperature range for a long time, and industrial and practical value becomes large. Things.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-15610 (JP, A) JP-A-2-28916 (JP, A) JP-A-3-64905 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H01G 9/035

Claims (1)

(57) [Claims] An electrolytic solution comprising ethylene glycol as a main solvent and boric acid or a salt thereof dissolved in an organic acid or a salt thereof, wherein at least one of nitroacetophenone and nitrobenzamide is contained in an amount of 0.1 wt% to 0.5 wt%. An electrolytic solution for driving an electrolytic capacitor, characterized in that it is added in an amount of less than.