JP2869162B2 - Glue for manganese dry batteries - Google Patents

Description

The present invention relates to a sizing agent for manganese dry batteries, and more particularly to a sizing agent which does not require mercury for corrosion protection of zinc.

<< Conventional Technology >> In a manganese dry battery, a paste is used for a separator that separates a zinc can constituting a negative electrode from a positive electrode mixture. A small amount of mercury is included for corrosion protection of zinc cans together with an aqueous solution such as ammonium.

However, mercury is a pollutant, and it is an issue to achieve mercury-free.

<< Problems to be Solved by the Invention >> In this case, if mercury is simply removed from the paste, the zinc can is easily corroded during storage, which causes a problem in storage performance.

Therefore, the present inventors have studied various anticorrosion agents as a substitute for the mercury, and have noticed that an anionic surfactant composed of an alkyl ether sulfate or a salt thereof exhibits a remarkable anticorrosion effect. Thus, the present invention has been completed.

<< Means for Solving the Problems >> To achieve the above object, the present invention relates to a paste used for a separator for separating a zinc can and a positive electrode mixture,
This paste contains an anticorrosive selected from an anionic surfactant composed of an alkyl ether polyesulfate or a salt thereof.

The sizing agent is generally a mixture of an electrolyte obtained by dissolving a mixture of zinc chloride and ammonium chloride in water, and a starch composed of flour and corn starch. To this, a small amount of the surfactant is added.

Nonionic surfactant consisting of an alkyl allyl ether of polyethylene oxyethylenic used as corrosion inhibitor has the general formula: is represented by the R-SO ₃ H or R-SO ₃ Me,.

However, the following procedure is used to prepare a glue having at least one composition selected from the group consisting of R = C5 to C30 and n = 5 to 20 Me = Na and K, and to assemble the battery.

A predetermined amount of corn starch and flour are dry mixed.

An electrolytic solution to which a predetermined amount of the surfactant has been added in advance is added thereto, and the mixture is wet-mixed to complete the preparation of the size liquid.

The prepared size liquid is poured by a conventional method into a zinc can having an open end, and then the positive electrode mixture thus formed is charged into the zinc can. The size liquid is uniformly interposed, and both are separated by the size liquid.

The zinc can is heated to gelatinize the size liquid, and then the opening of the zinc can is covered with a positive terminal plate via an insulator to complete the unit cell.

If the amount of the surfactant is less than 0.1% (weight, the same applies hereinafter) with respect to the total amount of the sizing agent, no effect as an anticorrosive agent is observed. So that the amount added is 0.1 to 0.5
% Is the appropriate range.

In consideration of other adverse effects and economy, it is preferable that the amount of the surfactant added is limited to the lower limit of 0.1%.

<< Effect >> The addition of a surfactant produces an anticorrosion effect even with mercury-free.

This is presumably because the hydrophilic group in the above general formula is adsorbed on the zinc can side, and the hydrophobic group shields the electrolyte.

<< Effects of the Invention >> As described above, in the present invention, mercury is not contained in the paste, which has a great effect on pollution prevention, and also causes problems such as storability and corrosion due to mercury-free. Nothing.

<< Example >> Next, an example of the present invention will be described. However, it is not limited to the following embodiments.

Pastes having the compounding ratios of Examples and Comparative Examples 1 and 2 shown in Table 1 below were prepared by the above-described procedure. The numerical value of the composition is gram.

The electrolytic solution has a commonly used composition, and has the following composition ratio.

H ₂ O: ZnCl ₂ : NH ₄ Cl = 100: 22: 38 As the anionic surfactant composed of an alkyl ether sulfate used in the examples, Alscope DB-55 (manufactured by Toho Chemical Co., Ltd.) The real value of the formulation is 0.1% of the total amount which is the lower limit of the present invention.
% Is set.

Next, the paste of each composition described above was incorporated into a manganese dry battery according to the above procedure to prepare a battery, and each of these 30 batteries was examined at a temperature of 45 ° C. for 3 months to investigate the weight loss of the zinc can. As a result, in the case of the example, no pinholes were generated at all, as in the case of adding mercury of Comparative Example 2, and no loss of corrosion was observed.

On the other hand, in the case where the anticorrosive agent of Comparative Example 1 was not added, 10 out of 30 (the occurrence rate of 33%) was 2
Pinholes penetrating ~ 30 places of zinc cans have occurred,
A significant difference was apparent from the present invention.

From the above, it was confirmed that the surfactant added in the above-described amount produces the same anticorrosion effect as mercury in the paste.

Furthermore, initial characteristics and 45 in Examples and Comparative Examples
As a result of investigating electrical characteristics such as open-circuit voltage, short-circuit current, and continuous discharge performance after storage at ℃ 3 months, the results shown in Tables 2 and 3 below were obtained.

From the results shown in Tables 2 and 3, it was confirmed that in the present invention, even after the initial storage and after storage for 3 months, the electrical characteristics were comparable to those of Comparative Example 2 to which mercury was added, and the variation was also reduced. Was.

As a precautionary measure, a paste obtained by adding 0.1 g (0.05% based on the total amount) of the same surfactant below the lower limit of the present invention to the paste of the above composition was stored under the same conditions. About 8 points were confirmed, and the anticorrosion effect was reduced.

Therefore, at least the amount of addition shown in the examples can exhibit the same corrosion protection as mercury.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Takashi Takeshima, Inventor 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd. (72) Tomoyuki Nagai 5-36-11, Shimbashi, Minato-ku, Tokyo In Fuji Electric Chemical Co., Ltd. (56) References Hikaru 2-77858 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01M 2/16 H01M 6/06 H01M 4 / 06-4/12

Claims (1)

(57) [Claims] 1. A sizing agent used for a separator for separating a zinc can and a positive electrode mixture, wherein the sizing agent is an anticorrosive selected from an anionic surfactant comprising an alkyl ether sulfate or a salt thereof. A sizing agent for manganese dry batteries, characterized by containing.