JPH03102811A - Electrolyte for electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent deterioration of characteristic due to cleaning with cleanser of halogen hydrocarbon by dissolving benzoic acid as solute in solvent containing gamma-butyrolactone as a main ingredient, ethylene glycol and water, dissolving monoalkylamine or dialkylamine, and specifying its pH. CONSTITUTION:Solvent of electrolyte contains gamma-butyrolactone as a main ingredient, 25wt.% or less of ethylene glycol and 0.1-8wt.% of water. Benzoic acid is dissolved as salute. In order to adjust its pH to 4-7.5, monoalkylamine or dialkylamine is added. The gamma-butyrolactone of the main ingredient in the solvent surrounds the halogen cleanser molecules to prevent the cleanser from being brought into contact with the water so as to suppress hydrolysis. The monoalkylamine or dialkylamine traps chlorine ions generated through the hydrolysis of the cleanser and exhibits strong correction suppressing action.

Description

[Detailed description of the invention] (Industrial use portion) The present invention relates to an electrolytic solution for electrolytic capacitors.

(Junior's technology) Conventional electrolytic capacitors such as aluminum lightning capacitors are made by winding an anode foil connected to a lead wire, a separator, and a cathode foil in layers to form a capacitor element, which is then impregnated with an electrolytic solution to form a case. It is stored in a case, and a lid is attached to the case to create a sealed structure (Xu).

Etched aluminum foils are used for the positive #1 foil and the negative electrode foil, and in particular, the former is chemically converted to form a dielectric oxide film.

By the way, when electronic components such as electrolytic capacitors are connected to a printed circuit board, 1,1,1-trichloroethane or 1,1,2-trichloroethane is used to remove flux and dirt contained in the solder used for connection. The cleaning process is performed using a halogen-based cleaning agent such as 1,2,2-trifluoroethane (Freon 113).

(Problem to be Solved by the Invention) However, in the permeation capacitor having the conventional structure, cleaning liquid may sometimes enter through the gap between the case and the case.

When the cleaning solution enters the case, it reacts with the water contained in the electrolyte to liberate chlorine ions, which cause corrosion of the anode and cathode foils. As a result, defects such as significant deterioration of the electrolytic capacitor's gas characteristics or loss of its function as a capacitor occur.

In order to prevent this drawback, some electrolytic capacitors have a structure in which epoxy resin is applied to the outer surface of the lid, but this requires the application of the resin and its curing process, making the manufacturing process complicated and time-consuming. be.

In addition, gf! such as nitro compounds such as P-nitrophenol and P-nitrobenzoic acid, and silver compounds are added to the electrolyte. Inhibitors may also be added. However, P-nitrophenol is yellow and has an extremely strong staining property, which causes problems in workability as it stains cases, hands, etc. P-nitrobenzoic acid does not have any dyeing problems, but even when added in a small amount, the constant spark pressure decreases and the pressure resistance is low. Also,
Conventional corrosion inhibitors are Freon 11, which has less dissociation of FA elements.
It shows a relatively good corrosion inhibiting effect against 1.
1.1-Trichloroethane has the disadvantage of low effectiveness.

The object of the present invention is to improve the above-mentioned drawbacks and to provide an electrolytic solution for detoxification capacitors that can prevent the deterioration of characteristics caused by cleaning with a halogenated hydrocarbon-based cleaning solution.

(Means for Solving the Problems) In order to achieve the above-mentioned objectives, Masaaki Moto developed a solution containing γ-butyrolactone as a main component, 25 wt% or less of ethylene glycol, and 0.1 to 3 wt% of water. The present invention provides a detoxification solution for electrolytic capacitors, which has benzoic acid as a solute and monoalkylamine or dialkylamine dissolved therein to have a pH of 4 to 7.5.

(Function) γ-Butyrolactone, which is the main component in the solvent, surrounds the molecules of the halogen-based cleaning liquid, prevents the cleaning liquid from coming into contact with water, and has the effect of suppressing hydrolysis.

Furthermore, monoalkylamines and dialkylamines trap chlorine ions generated by hydrolysis of the cleaning solution, and exhibit a strong corrosion inhibiting effect.

(Example) Hereinafter, the present invention will be explained based on examples.

The solvent for the defroster solution is mainly composed of γ-butyrolactone, 25 wt% or less of ethylene glycol, and 0.1 to 8 w of water.
Consists of t% components.

Dissolves benzoic acid as a solute.

Also, adjust the pH to 4-7.5! Then, add heptanoalkylamine or dialgylamine. ●For monoargylamine, use monomethylamine, monoethylamine, or monobrobylamine. Dimethylamine, diethylamine, or dibropylamine is used as the dialkylamine.

Next, an aluminum lightning capacitor with a rating of 250V-470 μF was made by impregnating it with the lightning solution of the embodiment of the present invention, the comparative example, and the conventional example! J-build. And these condensation→ノ,
Pour 1,1,"L-trichloroethane at a temperature of 50℃ into a cleaning tank, wash for 15 minutes, and then reduce the temperature to 110℃.
A high-temperature load test was conducted by placing the specimen in a high-temperature Igt ~ and applying a pressure of 250 V to investigate the state of corrosion. The number of samples is 30lI for the example, comparative example, and conventional example! After the test time of 500 hours, the 10th side was disassembled and the test time was 1000 hours.
After that, the remaining 20 pieces were dismantled and the corrosion status of each piece was investigated.

The results were as shown in the table.

Below is the crowd.

As is clear from the table, according to Examples 1 to 4 of the present invention, there was no corrosion even after 500 hr and 1000 hr, while in Conventional Example 1 and Conventional Example 2, the corrosion was 1.
After 000 hours, r94 meals had occurred in all the animals. Furthermore, as is clear from Comparative Example 1 and Comparative Example 2, if the content of ethylene glycol exceeds 25w%, the
Afterwards, corrosion occurs in 8 and 12 cases, respectively, and the corrosion suppression effect decreases. Further, as is clear from Comparison @ 3 and Comparative Example 4, when water is not included, the specific resistance increases, and as per the present invention, when water is included, the specific resistance can be lowered.

In addition, the solvent was γ-butyrolactone 75wt%, ethylene glycol iQwt%, water, and the solute was benzoin M10w.
The figure shows the change in specific resistance when the water content is changed in an electrolytic solution consisting of 5 wt % of diethylamine and 5 wt % of diethylamine.

As is clear from the figure, when the water content exceeds Bwt%, the specific resistance hardly changes. Furthermore, it is generally known that the more water is added, the more gases are generated and the life of the capacitor is shortened. Furthermore, if water is not added, the chemical formation properties will be very poor. Therefore, the appropriate amount of water to be added is 0.1 to 8w1%.

As described above, according to the present invention, the corrosion inhibiting effect can be improved because the main component is γ-butyrolactone and heptanoalkylamine and dialkylamine are dissolved. By dissolving ethylene glycol, the spark voltage can be increased by dissolving
By adding in a range of 8 wt%, a solution for a dragon capacitor with low resistivity can be obtained.

[Brief explanation of drawings]

The figure shows a graph of changes in specific resistance when the content of water in the electrolyte is changed.

Claims (1)

[Claims] (1) In a solvent containing γ-butyrolactone as a main component, 25 wt% or less of ethylene glycol, and 0.1 to 8 wt% of water, benzoic acid is dissolved as a solute, and monoalkylamine or dialkylamine is dissolved, P
An electrolytic solution for electrolytic capacitors with H of 4 to 7.5.