JP2001325965A - Manufacturing method of manganese dry battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a manganese dry battery in which an amount of alcohol used as a solvent, dispersion characteristic of the paste grain is secured, a surface condition of an application plane after an application and a drying are also good, and also strong load discharge electricity characteristics are excellent, concerning the solvent for a paste applied to a separator. SOLUTION: A mixed solvent of alcohol and water is used for the distribution solvent of the paste material applied to the separator, and still more preferably, the solvent in the paste exists in a range of 10-20 weight % of alcohol, and 30-40 weight % of water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manganese dry battery, and more particularly to a manganese dry battery which is excellent in heavy load discharge performance by using a novel separator.

[0002]

2. Description of the Related Art A separator in a manganese dry battery is prepared by dispersing starch and a small amount of a binder substance in water or an alcohol solvent on kraft paper (base paper), applying the paste liquid with a roller or the like, and then subjecting the paste to a hot air atmosphere. It is manufactured by passing through and drying. That is, water or alcohol is generally used alone as a dispersion solvent for "starch and a small amount of binder substance" (hereinafter referred to as a "sizing material") during the preparation of the size liquid, and alcohol is especially heavily used.

[0003]

However, when water is used alone as a dispersing solvent for the paste material, the binder substance, the crosslinked starch as a starch substance, and the crosslinked etherified starch particles are uniformly dispersed in the solvent. Instead, they become lumps and form crater-like depressions during the coating on the base paper and the subsequent hot-air drying step. As a result, there is a problem that the battery discharge performance is adversely affected.

On the other hand, when alcohol, which is a conventional dispersion solvent, is used, the dispersibility of the binder substance, crosslinked starch, and crosslinked etherified starch particles in the solvent and the surface condition of the coated surface after coating and drying are reduced. Although improved, costs are high and there are environmental issues such as disposal.
Also, the discharge performance was particularly insufficient for heavy load discharge performance.

The present invention has been made to solve the above-mentioned problem, and as for the dispersing solvent for the paste material for the separator, the dispersibility of the binder substance, the crosslinked starch and the crosslinked etherified starch particles is ensured while reducing the amount of alcohol used. Also, the surface condition of the coated surface after coating and drying is good,
It is another object of the present invention to provide a method for manufacturing a manganese dry battery which is excellent in heavy load discharge performance by improving ion diffusion.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, a method of manufacturing a manganese dry battery according to the present invention is directed to a method of manufacturing a manganese dry battery including a positive electrode mixture containing manganese dioxide as a positive electrode active material, a negative electrode zinc, and a separator. The method
The separator is obtained by applying a paste containing a starch substance, a binder substance and a dispersion solvent to a separator base paper and then drying the paste, and using a mixed solvent of alcohol and water as a dispersion solvent in the paste liquid. The solvent in the size liquid is preferably in the range of 10 to 20% by weight of alcohol and 30 to 40% by weight of water.

[0007] This makes it possible to improve the heavy-load discharge performance while ensuring the dispersibility of the paste material in the paste.
Furthermore, by reducing the amount of alcohol used, we can respond to environmental considerations and reduce equipment costs.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a manganese dry battery comprising a positive electrode mixture containing manganese dioxide as a positive electrode active material, a negative electrode zinc, and a separator, wherein the separator comprises starch, a binder material, a dispersion solvent, Is applied to a separator base paper and dried, and a solvent obtained by mixing alcohol and water is used as a dispersion solvent in the paste liquid. By using a mixed solvent of alcohol and water as a dispersing solvent for the paste material, while reducing the amount of alcohol used, the binder material and the starchy crosslinked starch, the dispersibility of the crosslinked etherified starch particles are also ensured, and To provide a manganese dry battery that is excellent in heavy load discharge performance by improving ion diffusion.

When a mixed solvent of alcohol and water is used as the dispersion solvent, the swelling state of the paste material can be made uniform, and by using this separator, the heavy load discharge performance of the battery can be improved. Can be. This is because the swelling state of the paste material becomes uniform, so that the diffusion and movement of ions in the separator are performed smoothly, the rise of the internal resistance is suppressed, and as a result, the battery reaction is accelerated and the heavy load discharge performance is improved. It is considered that this has improved.

Further, it is preferable that the content of alcohol used as a dispersion solvent for the size liquid is 10 to 20% by weight and the content of water is 30 to 40% by weight based on the size liquid.

[0011] When the alcohol and water are below the respective lower limits, the viscosity of the size liquid is too high, so that application unevenness to the separator substrate is likely to occur. When the upper limit is exceeded, the concentration of the size material in the size liquid is too low. The amount of glue necessary for the separator base material cannot be secured. When the ratio of alcohol to water exceeds the maximum value of the ratio of water in the blending ratio, that is, the upper limit of water (40% by weight) / the lower limit of alcohol (4% by weight) of 4, the glue material becomes solvent. It is not preferable because it is difficult to be uniformly dispersed in the inside and the glue material tends to be in a lump. on the other hand,
The minimum value of the ratio of water, ie, the lower limit value of water (30% by weight) / the upper limit value of alcohol (20% by weight) is 1.5.
If it is less than the above, the effect of improving the discharge performance is not exhibited.

It is preferable that the paste liquid contains an etherified polysaccharide of a vegetable sticky substance. The etherified polysaccharide of plant sticky substances is a polysaccharide mainly composed of D-galactose, D-mannose and the like obtained by extracting from locust bean (carob), guaran bean, guar gum, etc. obtained on the Mediterranean coast. And polysaccharides etherified with polyethylene oxide, propylene oxide or ethylene chlorohydrin. Specifically, for example, guar gum having a degree of etherification of 0.1 to 0.3 mol% with propylene oxide is used.

[0013] Etherified polysaccharides of plant adhesives are superior in water retention, viscosity increase and acid resistance as compared with natural starch, crosslinked starch, crosslinked etherified starch, etc. because of their high hydrophilicity. Therefore, when used as a sizing material in a sizing solution, the zinc ions in the sizing material layer applied to the separator base material increase due to the discharge reaction, and the pH generated in the sizing material layer decreases, resulting in an acid generated. Since the particles are less likely to be disintegrated, the retention of the electrolyte is good and the storage performance is excellent.

However, since the etherified polysaccharide of the vegetable sticky substance has a low concentration and a high viscosity when dissolved in water, the viscosity sharply increases when dispersed in a mixed solvent of water and alcohol, and the dispersion is uniform. The size liquid is produced without being subjected to the above operation. Therefore, when the viscosity of the etherified polysaccharide of the vegetable sticky substance sharply increases, the etherified polysaccharide itself of the vegetable sticky substance is not uniformly dispersed in the solvent and becomes a mass. As a result, uneven application of the paste liquid to the separator base material occurs, and the yield is reduced, which impairs productivity.

For this reason, it is preferable that the paste liquid is prepared by dispersing the etherified polysaccharide of the vegetable adhesive substance in alcohol, adding water, and then mixing the mixture of the starchy substance and the binder substance. The etherified polysaccharide of the vegetable adhesive is dispersed uniformly in water-compatible alcohol, and then the viscosity of the paste liquid is adjusted by adding water. After adding the etherified polysaccharide of the plant adhesive, water is added to increase the viscosity, but the binder material and starch added in the next step do not immediately swell, so that it is difficult to form a block (spring), It can be uniformly dispersed.

As the alcohol for the dispersion solvent, ethyl alcohol, methyl alcohol, etc. may be used alone or as a mixture.

Examples of the starch include crosslinked starch and crosslinked etherified starch, and these can be used alone or in combination.

Examples of the binder substance include a copolymer of vinyl acetate and crotonic acid, and a water-soluble binder is preferable.

A negative electrode zinc can used in the dry battery of the present invention;
There is no particular limitation on the positive electrode mixture, the carbon rod, the sealing body, the exterior material, and the like, and those conventionally used can be used.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to only the examples in the examples, and the materials of the respective constituent members are not limited to the examples.

FIG. 1 is a structural sectional view of a manganese dry battery of the present invention. In FIG. 1, a negative electrode zinc can 4 is formed by molding metal zinc into a cup shape, is filled with a positive electrode mixture 1 via a separator 3, and a carbon rod 2 having carbon powder hardened is inserted into the center thereof. Have been. The separator 3 is made of a kraft paper having one surface coated with a paste material mainly composed of cross-linked starch. The separator 3 is disposed so that the surface on which the paste material is applied faces the negative zinc can 4. The agent 1 and the negative electrode zinc can 4 are separated. The positive electrode mixture 1 is a powdery material prepared by mixing manganese dioxide, conductive carbon black, and an electrolytic solution at a constant weight ratio of 50% by weight, 10% by weight, and 40% by weight, respectively. The electrolyte was prepared at a ratio of 30% by weight of zinc chloride and 70% by weight of water.

The carbon rod 2 penetrates through the center hole of the sealing body 5 and the flange paper 9, and the upper part is in contact with the positive electrode terminal plate 11, and functions as a current collector on the positive electrode side. The sealing body 5 is formed by molding a polyolefin-based resin such as polyethylene or polypropylene, nylon, or the like, and has a hole in the center portion into which the carbon rod 2 is inserted. The flange paper 9 is formed by punching a paperboard into an annular shape having a center hole.

The outer peripheral side of the negative electrode zinc can 4 is covered with a resin tube 8 made of a heat-shrinkable resin film for securing insulation, and the upper end thereof covers the outer peripheral upper surface of the sealing body 5. Cover, the lower end of which is a seal ring 7
The lower surface is covered.

The positive electrode terminal plate 11 is made of a tin plate, and has a central portion in the shape of a cap which covers the upper end of the carbon rod 2.
The outer peripheral portion has a flat plate shape. An insulating ring 12 made of resin is arranged in contact with the flat outer surface of the positive electrode terminal plate 11. A seal ring 7 formed by punching a paperboard impregnated with paraffin into a ring shape in a state of being in contact with the outer surface of the flat outer peripheral portion of the negative electrode terminal plate 6 is arranged.

The metal jacket 10 is formed by rolling a tin plate into a tubular shape, and is disposed on the outer peripheral side of the resin tube 8. The lower end is bent inward, and the upper end is curled inward. And the tip is an insulating ring 1
2, the insulating ring 12, the flat outer peripheral portion of the positive electrode terminal plate 11, the upper end portion of the resin tube 8, the outer peripheral portion of the sealing body 5, the open end portion of the negative electrode zinc can 4, and the lower end of the resin tube 8 , The seal ring 7 and the negative electrode terminal plate 6 are fixed at predetermined positions, respectively.

Using the R6 manganese dry battery configured as described above, batteries of the examples and comparative examples of the present invention were manufactured and their characteristics were evaluated. (Example 1) A separator used in a manganese dry battery of the present invention was prepared using a solvent in which the mixing ratio of alcohol and water to the entire size liquid was 15% by weight of alcohol and 35% by weight of water. The manganese dry battery manufactured using the battery was used as the battery of Example 1. A battery of Comparative Example was prepared in the same manner as the battery of Example 1, except that the solvent in the paste liquid was prepared with a single solvent of 50% by weight of alcohol. The composition ratio of the size liquid is shown in (Table 1). In addition, a crosslinked starch, a crosslinked etherified starch, and a water-soluble binder were used as the paste material, and ethyl alcohol was used as the alcohol.

[0027]

[Table 1]

Five similar dry batteries were prepared, and for each battery, 3.9 Ω continuous discharge (final voltage 0.8 V) at room temperature after initial storage and storage at 45 ° C. for one month, and 1.8.
A Ω pulse discharge (a 15-second discharge / 45-second discharge pause cycle was continuously repeated: cut-off voltage 0.9 V) test was performed, and the duration was measured. The results are shown in (Table 2).
The performance numerical values in (Table 2) are calculated from the average value of n = 5, and show the comparative values (index) when the performance of the comparative example is set to 100.

[0029]

[Table 2]

As shown in Table 2, the battery of the present invention has improved initial discharge performance as compared with the battery of the comparative example.

In this embodiment, since the paste material is uniformly dispersed in the solvent, the paste material does not clump and the crater-shaped depressions are formed during the hot air drying step after the paste is applied onto the base paper. Did not occur.

In this embodiment, the mixing order of the alcohol, water and the cross-linking starch, the cross-linked etherified starch and the water-soluble binder as the sizing material does not affect the performance. Can be efficiently dispersed in a mixture of crosslinked starch and crosslinked etherified starch. Example 2 The separator used in the manganese dry battery of the present invention used a solvent in which the mixing ratio of alcohol and water was 15% by weight of alcohol and 35% by weight of water with respect to the entire size liquid, and guar gum was used as a size material. 3% by weight of plant-adhesive etherified polysaccharide having a degree of etherification of 0.1 to 0.3 mol% with propylene oxide, 12% by weight of crosslinked starch, 25% by weight of crosslinked etherified starch, 10% by weight of water-soluble binder , And the batteries of Examples 2 and 3 were manufactured using the same. The composition ratio of the size liquid is shown in (Table 1).

However, in the battery of Example 2, the etherified polysaccharide of the vegetable adhesive was dispersed in a mixed solvent of alcohol and water, and then the mixture of crosslinked starch, crosslinked etherified starch and a water-soluble binder was used. A separator prepared by dispersing a paste liquid was used. In addition, the battery of Example 3
After dispersing the etherified polysaccharide of the plant-based adhesive in alcohol, water was added, and then a mixture in which a mixture of crosslinked starch, crosslinked etherified starch and a water-soluble binder was dispersed to prepare a paste liquid was used. Ethyl alcohol was used as the alcohol.

Five similar dry batteries were prepared, and for each battery, a 3.9 Ω continuous discharge at room temperature after initial storage and storage at 45 ° C. for one month (final voltage 0.8) was performed in the same manner as in Example 1.
V) and 1.8Ω pulse discharge (final voltage 0.9V)
The test was performed and the duration was measured. The results are shown in (Table 3). The performance values in Table 3 were calculated from the average value of n = 5, and the performance of the comparative example used in Example 1 was 1
The comparison value (index) when 00 is set is shown.

[0035]

[Table 3]

As shown in Table 3, the battery of the present invention has improved initial discharge performance and discharge performance after storage at 45 ° C. for one month as compared with the battery of the comparative example.

However, in the battery of Example 2, the viscosity of the etherified polysaccharide of the vegetable sticky substance sharply increased, and the etherified polysaccharide of the vegetable sticky substance itself was not uniformly dispersed in the solvent, but formed a mass. As a result, uneven coating on the separator base material was generated, and the yield was reduced.

The mixing ratio of alcohol and water to the whole size liquid is preferably in the range of 10 to 20% by weight of alcohol and 30 to 40% by weight of water. Viscosity is too high and coating unevenness is likely to occur.If the alcohol and water exceed their respective upper limits, the concentration of the paste material in the paste liquid is too low to secure the amount of paste required for application to the separator substrate. Can not.

In the ratio of alcohol to water, the maximum value of the ratio of water in the compounding ratio of the present invention, that is, the upper limit value of water (40% by weight) / the lower limit value of alcohol (10% by weight) is 4 If it exceeds, the paste material is difficult to be uniformly dispersed in the solvent, and the paste material is likely to be in a lump, which is not preferable.
On the other hand, the minimum value of the water ratio, that is, the lower limit value of water (30
%) / 1.5, which is the upper limit of alcohol (20% by weight), the effect of improving discharge performance is not exhibited.

In this embodiment, ethyl alcohol is used as the alcohol, but low-cost methyl alcohol may be used.

[0041]

As described above, according to the present invention,
Compared to the case where the conventional alcohol solvent is used alone, the amount of alcohol used can be reduced and the heavy load discharge performance of the manganese dry battery can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a cylindrical manganese dry battery of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode mixture 2 Carbon rod 3 Separator (wrapping paper) 4 Zinc can 5 Sealing body 6 Negative terminal plate 7 Seal ring 8 Resin tube 9 Flange paper 10 Metal jacket 11 Positive terminal plate 12 Insulating ring 13 Bottom paper

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Hase 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. Terms (reference) 5H021 AA02 BB12 BB13 CC02 EE00 EE13 EE23 EE33 HH01 5H024 AA03 AA06 AA14 BB02 BB07 BB08 BB18 CC02 CC14 DD09 EE09 FF04 FF31 GG01 GG02 HH01

Claims (4)

[Claims] 1. A method for producing a manganese dry battery comprising a positive electrode mixture containing manganese dioxide as a positive electrode active material, negative electrode zinc, and a separator, wherein the separator comprises starch, a binder substance, and a dispersion solvent. A method for producing a manganese dry battery, comprising applying a solvent to a separator base paper and drying it, and using a solvent obtained by mixing alcohol and water as a dispersion solvent in the paste liquid. 2. The content of alcohol used as a dispersion solvent for the size liquid is 10 to 20% by weight with respect to the size liquid, and the content of water is in the range of 30 to 40% by weight.
A method for producing the manganese dry battery according to the above. 3. The method for producing a manganese dry battery according to claim 1, wherein the paste liquid contains an etherified polysaccharide of a vegetable sticky substance. 4. The paste liquid is prepared by dispersing an etherified polysaccharide of a plant sticky substance in alcohol, adding water, and then mixing the starchy substance and a binder substance.
A method for producing the manganese dry battery according to the above.