JPS6226145B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a gasket material for insulating and sealing an opening in an alkaline battery, and particularly relates to an improvement in leakage resistance. Conventionally, in alkaline batteries, insulating gasket materials made of rubber-based materials containing chloroprene rubber as a main component, polyamide resins, polyethylene resins, etc. have been used as gasket materials for sealing the openings.
However, these batteries use an alkaline electrolyte, and because the liquid rises significantly due to the so-called electrocapillary phenomenon, leakage often occurs from the gap between the insulating gasket and the cathode or anode can, causing the terminal surface to become damaged. It was dirty and caused poor contact. In cases where there is significant leakage, the inside of equipment using alkaline batteries gets wet, causing corrosion and damage to parts, which can lead to serious accidents. The present invention aims to improve these drawbacks, and by adding carbon black (hereinafter abbreviated as CB), titanium white rutile, or titanium white anatase to nylon 66, it has excellent stress relaxation resistance and is suitable for battery containers and assemblies. The object of the present invention is to obtain a gasket material with good adhesion to metal parts such as electric bodies, and to provide an alkaline sealed battery with significantly improved leakage resistance. Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a metal container which also serves as an anode terminal, and houses an anode forming mixture 2 mainly composed of silver oxide, a separator 3 made of cellophane, grafted polyethylene, etc., and an electrolyte impregnated material 4 such as cotton, cotton paper, or nonwoven rayon fabric. are doing. Reference numeral 6 denotes a cathode can which also serves as a cathode terminal, and houses a cathode mixture 5 made of a mixture of zinc chloride powder and a gelling agent such as carboxymethyl cellulose which is formed into a gel by pressure molding or alkaline solution. 7 is an insulating gasket according to the present invention. Next, an example of an insulating gasket to which the present invention is applied will be described. Example 1 After mixing carbon black with nylon 66
Carbon black was uniformly dispersed in nylon 66 by melting at 250°C. This CB-filled nylon 66 was formed into a ring shape with an L-shaped cross section, and using this as a gasket, a battery as shown was assembled. We made 200 batteries each using gaskets of CB-containing nylon 66 with a CB content of 0.1, 0.4, 1.0, 2.0, and 3.0% by weight, respectively.
The number of samples that showed leakage after being left at 40°C and 95% relative humidity for 1,000 hours and also after being left for 2,000 hours was counted. For comparison with conventional batteries, a similar battery using a conventional gasket made of nylon 66, which does not contain CB, was also investigated under similar conditions. The results are shown in Table 1. In this example and the following examples, all batteries have an outer diameter of 11.6 mm and a thickness of 3.6 mm.

[Table] It is clear from this table that leakage is significantly reduced when CB is added. Although Table 1 only shows the number of batteries that leaked, the amount of leakage was also greatly improved. When the amount of carbon black contained is less than 0.1% by weight, there is not much improvement in terms of leakage compared to normal nylon 66, while when it is more than 2% by weight,
There is a problem with insulation, and the content of carbon black in nylon 66 is limited to 0.1 to 2% by weight. Example 2 Instead of the carbon black in Example 1, 0.4% by weight of each of titanium white rutile and titanium white anatase were mixed into nylon 66 in the same manner as in Example 1. We make nylon 66 gaskets with white rutile and nylon 66 gaskets with titanium white anatase.
A battery similar to that in Example 1 was assembled using them. 0.4% titanium white rutile filled nylon above
200 batteries each using a 66 gasket and a battery using a nylon 66 gasket containing 0.4% titanium white anatase were made, and a leakage resistance test similar to that shown in Table 1 in Example 1 was conducted under the same conditions. Summer. The results are shown in Table 2. For comparison, the results for a battery using a 0.4% by weight CB-containing nylon 66 gasket are also quoted from Table 1.

[Table] As examples above, we have described batteries using gaskets made of nylon 66 to which carbon black, titanium white rutile, and titanium white anatase have been added. It is expected that even if two or more selected inorganic pigments are added to nylon 66, they will be effective in improving leakage resistance. Finally, carbon black, titanium white rutile,
The reason why leakage resistance is improved by using a gasket made of nylon 66 to which an inorganic pigment such as titanium white anatase is added is presumed to be as follows. That is, nylon 66, which is a polyamide resin.
The addition of the inorganic pigment promotes crystallization, thereby increasing mechanical strength and improving stress relaxation resistance. Therefore, after a gasket made of nylon 66 containing inorganic pigments is inserted between the anode and cathode cans of a battery and sealed under pressure to seal the battery opening, it resists creep deformation over a long period of time. Because it will be. As described above, nylon to which 0.1 to 2% by weight of carbon black or 0.4% by weight of titanium white rutile or titanium white anatase according to the present invention has been added
The alkaline sealed battery using a gasket made of 66 has the advantage of being able to significantly improve leakage resistance compared to conventional batteries.

[Brief explanation of the drawing]

The drawing is a sectional view showing the basic structure of the alkaline sealed battery of the present invention. 1... Anode can, 2... Anode mixture, 3... Separator, 4... Electrolyte impregnated material, 5... Cathode mixture, 6
...Cathode can, 7...Insulating gasket.

Claims (1)

[Claims] 1. An alkaline sealed battery, characterized in that it is sealed with a gasket made of a resin composition in which 0.1 to 2% by weight of carbon black or 0.4% by weight of titanium white rutile or titanium white anatase is added to nylon 66.