JPS6252426B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to alkaline batteries such as silver batteries, mercury batteries, alkaline manganese batteries, and nickel-zinc batteries.In particular, the present invention relates to alkaline batteries such as silver batteries, mercury batteries, alkaline manganese batteries, and nickel-zinc batteries. In this case, leakage of the alkaline electrolyte due to corrosion or excessive amalgamation of the copper layer used as the innermost layer is prevented, thereby providing an alkaline battery with good storage performance. Figures 1 and 2 show a cross-sectional view and a partial cross-sectional view, respectively, of a button-type silver oxide battery or an alkaline manganese battery. The active material 2, separator 3, and electrolyte-containing liquid 4 are inserted in sequence, while the sealing plate 5, which also serves as a cathode terminal, is composed of a clad plate with a copper layer as the innermost layer, and contains zinc powder and gelled alkaline electrolyte. A cathode active material 6 made of a mixture is filled therein. A sealing plate 5 forming a cathode container is fitted into the opening of the anode container 1 via an insulating packing 7 made of synthetic resin such as polyamide resin or polyolefin resin, and the opening of the anode container 1 is curled inward. The battery is often hermetically sealed. Conventionally, insulating packing 7 includes resin packing whose surface is coated with a flexible sealant 8 such as polyisobutylene or polyamide, and flexible sealing made of two layers of low molecular weight polyamide and high molecular weight polyamide. It has been proposed that the material be coated with an inhibitor, and furthermore, that it be coated with a mixture of low molecular weight polyamide and high molecular weight polyamide. In addition, as the sealant 8, low molecular weight fatty acid polyamide, semi-inorganic polymer, asphalt, pitch,
Various methods such as microcrystalline wax, fluororesin, and silicone oil have been investigated, and although they have shown some effectiveness, they have not yet achieved a fully satisfactory sealing performance. Furthermore, chlorinated polyethylene disclosed in Japanese Patent Publication No. 52-47815 is superior to the above-mentioned sealants and is currently used as a practical sealant. However, even when these sealants are used, a sufficiently satisfactory sealing effect cannot be obtained, and the electrolyte may leak out from around the cathode sealing plate 5 during battery storage, causing a short circuit of the battery. Otherwise, accidents such as corrosion of external equipment using batteries and further reduction in battery capacity have occurred. In small button batteries, these accidents occur mostly due to the creep phenomenon peculiar to the alkaline electrolyte between the cathode sealing plate 5 and the insulating packing 7, except for those caused by manufacturing variations and variations in the shape and dimensions of parts. It was due to liquid leakage. These variations in dimensional accuracy are a problem caused by the finishing accuracy of raw materials or processing molds, etc., and although it can be improved to some extent, it is desirable to develop a sealant that is more effective in suppressing leakage and is stable even at high temperatures. was. The present inventors have previously discovered that certain amines and amides as sealants are effective in preventing the corrosion of sealing plate metals, especially in preventing amalgamation of cladding materials whose contact surfaces are copper. The number of mg of KOH equivalent to 1 g of amine measured by the method of Testing Association) D2074-62T.
Precisely weigh 0.5g to 5g into a 200ml Erlenmeyer flask and add each solvent (methyl cellosolve, butyl carbidol, or a mixed solvent of triol/butanol = 2/1 (volume ratio)) depending on the type of sample. ) and dissolve while heating. After cooling, add brome phenol blue (0.1% methanol solution) as an indicator, and dissolve with 1/2N or 1/10NHCl.
Calculated using the following formula, with the end point being the point at which the sample solution changes from blue to a yellowish color and then continues to turn yellow for 30 seconds. Amine value = [Normality of HCl standard solution] x [Titer of HCl standard solution] x 56.1 x [Required amount of HCl standard solution (ml)] / The higher the sample weight (g), the better the sealing performance. However, when the amine value was high, the sealing performance at high temperatures could not be said to be sufficient. In response to this, the present inventors have conducted extensive research and discovered the following fact, leading to the present invention. That is, an epoxy adduct polyamide containing an epoxy adduct polyamide amine or a mixture of the epoxy adduct polyamide amine and a solvent as a sealant for sealing between a sealing plate that also serves as a cathode terminal and an insulating packing. It was discovered that an alkaline battery with an amine layer interposed therein is an excellent alkaline battery without leakage, and also has excellent sealing properties at high temperatures. The epoxy adduct polyamide amine of the present invention comprises (1) one or more compounds selected from compounds having at least two epoxide groups in one molecule, and (2) at least two amino acids in one molecule. It is a reaction product obtained by reacting one or more compounds selected from the group-containing compounds. Note that the amino group here refers to -NH ₂ ,

It is represented by the formula: (R represents an alkyl group). The above-mentioned method of reacting a compound having an epoxide group with a compound having an amino group is possible by simply mixing them together, but in order to control the reaction, it is better to dissolve them in an appropriate solvent and react in a solution. good. In this case, heating may be performed if necessary. It is necessary to add an amount of active hydrogen to the compound having an amino group that is equivalent to or more than the epoxide group of the compound having an epoxide group, and it is important to leave unreacted amino groups. The compounds having the epoxide group include: 1. Bisphenol A epoxy resin 2. Polyglycol epoxy resin 3. Novolak epoxy resin 4. Alicyclic epoxy resin 5. Epoxidized soybean oil. Further, the compounds having an amino group include: 1 aliphatic diamine 2 aromatic diamine 3 fatty acid polyamide amine which is a reaction product of an unsaturated dibasic fatty acid and an aliphatic diamine. Next, the present invention will be explained in detail with reference to Examples. In Examples 1 and 2, the mixture ratio of bisphenol A type epoxy resin and fatty acid polyamide amine was changed and the reaction was carried out in a mixed solvent of toluene/isopropyl alcohol. In Example 3, a phenol novolac type epoxy resin and a fatty acid polyamide amine were reacted in a toluene/isopropyl alcohol mixed solvent.
In either case, dry the solvent thoroughly and assemble the battery as shown in Figure 1 at a temperature of 45℃ and a humidity of 90%.
The RH and number of leaks after storage for 8 weeks in an environment of 60°C and 90% RH were investigated. The number of samples was 50 in each case. The results are shown in Table 1.

[Table] As a result of the above, while the conventional chlorinated polyethylene described in Japanese Patent Publication No. 52-47814 does not stop leaking, alkaline batteries using epoxy adduct polyamide amine as a sealant have excellent leakage resistance. The liquid properties were shown. This is because epoxy adduct polyamide amine has an amino group in its molecular chain, which has a strong interaction with the copper surface, and has an epoxy chain in its molecular chain, so it has excellent heat resistance, and is not thermoplastic. It is thought that this makes it easier to relax the stress during assembly, which improves the sealing properties. As described above, the present invention significantly improves the leakage resistance of alkaline batteries by using epoxy adduct polyamide amine as a sealant between the sealing plate and the packing. In addition, when using epoxidized soybean oil and polyglycol type epoxy resin having epoxide groups,
According to the same evaluation as in Table 1, there were 5 to 10 leaks, and the alicyclic epoxy resin had zero leaks.
A compound having an epoxide group or an amino group is
Preferably, the compound has a molecular skeleton with a glass transition temperature of 80° C. or higher, and epoxy adduct amine with an amino group at the end is preferred.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the alkaline battery of the present invention, and FIG.
The figure is a partial sectional view showing the sealed portion of the alkaline battery. DESCRIPTION OF SYMBOLS 1... Anode container, 2... Anode active material, 3... Separator, 5... Sealing plate forming a cathode container, 6...
Cathode active material, 7... Insulating packing, 8... Sealing agent.

Claims (1)

[Claims] 1. An epoxy adduct polyamide amine layer containing an epoxy adduct polyamide amine or a mixture of the epoxy adduct polyamide amine and a solvent is interposed as a sealant for sealing between the sealing plate that also serves as a cathode terminal and the insulating packing. alkaline battery.