JP2993595B2 - Manufacturing method of manganese dry battery separator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a manganese dry battery separator, and more particularly to a method for producing a manganese dry battery separator in which a paste mainly composed of starch is applied to a separator base paper.

[0002]

2. Description of the Related Art A manganese dry battery generally has an internal structure as shown in FIG. That is, a separator 2 is mounted inside a negative electrode zinc can 1 having a bottomed shape along the inner peripheral surface of the negative electrode zinc can 1, and a positive electrode mixture 3 is loaded inside the separator 2. A carbon rod 4 is inserted into the center of the positive electrode mixture 3. The opening of the negative electrode zinc can 1 is closed with a plastic sealing gasket 5, and the upper end of the carbon rod 4 penetrates the center hole of the sealing gasket 5. Further, a positive electrode terminal plate 6 is put on the upper end of the carbon rod 4, and a negative electrode terminal plate 7 is put on the bottom outer surface side of the negative electrode zinc can 1.

[0003] The separator 2 is manufactured by applying a paste to the surface of a separator base paper. As a method of producing the paste, for example, a heating mixing method or a room temperature mixing method is known.

As shown in FIG. 5, corn starch J and longum CE-3 as starches are weighed and mixed with water, respectively, and an electrolytic solution is weighed and mixed therewith. Water and an electrolyte solution heated to about ° C are respectively measured and added, and the mixture is stirred and swelled with heating to gel. Then, after the solution was cooled to about 40 ° C. or lower, the solution was further stirred to obtain a paste for coating the separator.
This type of manufacturing method is disclosed, for example, in Japanese Patent Publication No. 57-32970.

In this heating and mixing method, it takes time to cool after heating, and the process becomes complicated. In addition, heating and cooling equipment is required, and gelatinization proceeds from heating to cooling. Therefore, there are various problems such as difficulty in obtaining an optimum viscosity as a paste applied to a separator for a manganese dry battery.

[0006] On the other hand, the room temperature mixing method is a method of producing a paste without performing a heat treatment, and uses room temperature water instead of heated water and eliminates heating during stirring. Has become. This is because a sedimentation preventing binder is appropriately mixed in and the stirring is constantly performed in order to prevent the sizing agent in the solution from settling. In particular, when raw starch is used, it is also stirred when it is applied to the separator base paper.

[0007] The paste obtained in this manner is
A separator base paper made of kraft paper having a thickness of 70 to 100 μm is coated on one surface with a roller so as to have a solid content of 20 to 40 g / m ^2, and then dried at a temperature of 110 ° C. or more to form a separator for a manganese dry battery. .

[0008]

However, in the conventional room temperature mixing method, the operation of mixing the binder for preventing sedimentation is complicated, and the stirring operation for applying the binder to the separator is also complicated. Further, when the paste is applied to the separator and then dried, the drying temperature is set at 11 ° C.
Because it is 0 ° C or more, it becomes excessively dry and cracks,
There may be problems such as curl and shrinkage,
There is also a problem that the drying time must be set precisely to obtain a stable separator, and the process control is complicated.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to produce a paste at room temperature, to greatly simplify the production process, and to obtain a stable separator. It is an object of the present invention to provide a method for manufacturing a separator for a manganese dry battery, which can easily perform the method.

[0010]

In the present invention in order to achieve the above object, according to an aspect of, after swelling the starch added and mixed aqueous solution of zinc chloride to the starch, water or hydroxide to this swelling was
An aqueous solution of cypropylcellulose is mixed to form a paste, and the paste is applied to a separator base paper. After the starch is mixed with the aqueous zinc chloride solution and swelled, water is added.
Therefore, even if this water or aqueous zinc chloride solution is at room temperature, starch
Does not settle. Therefore, there is no need to add a binder or constantly stir to prevent sedimentation. to this
If the paste is prepared at a normal temperature, it is possible to eliminate harmful effects such as a change in viscosity over time due to a high or low temperature or a change in temperature. Therefore, the optimum viscosity can be set only by adjusting the amount of water in the water or the aqueous solution of hydroxypropylcellulose after swelling. Therefore, the optimum viscosity of the paste can be easily obtained.

When the above-mentioned aqueous solution of hydroxypropylcellulose is used, the wettability is increased to accelerate the swelling of the starch,
Handling becomes simple.

Preferably, in adding and mixing the aqueous zinc chloride solution to the starch, the aqueous zinc chloride solution is added to the starch at a predetermined flow rate for about one minute while stirring the starch. I do. By controlling the mixing flow rate of the aqueous zinc chloride solution, swelling can be performed quickly and sufficiently, and the swelling time can be reduced.

[0013] More preferably, in adding and mixing the water or the aqueous solution of hydroxypropyl cellulose to the swollen product, the water or the aqueous solution of hydroxypropyl cellulose is added to the swollen product while stirring the swollen product. Add and mix at a predetermined flow rate for 10 to 15 minutes. By controlling the mixing flow rate of water or the aqueous solution of hydroxypropylcellulose in this manner, the water or the aqueous solution of hydroxypropylcellulose is favorably dispersed in the swollen material, and the generation of granular lumps can be reduced.

Preferably, the separator base paper coated with the paste is dried at a temperature in the range of 50 to 105 ° C., so that it can be dried at a lower temperature than in the past. Such problems can be solved, and a stable separator can be obtained.

In order to obtain a stable separator as described above, the basis weight of the paste relative to the separator (the solid content of the paste applied to the separator base paper) is 80 g / max.
up to m ² can be increased.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a separator for a manganese dry battery according to the present invention will be described below with reference to the accompanying drawings. The separator according to the present invention is obtained by applying a paste mainly composed of starch to a separator base paper, and is manufactured through the steps shown in FIG.

First, the production of the paste will be described. For starch, 100 parts by weight of corn starch J and 200 parts by weight of Longum CE-3, 300 parts by weight of 35.5.
% Zinc chloride aqueous solution is mixed at room temperature and swelled by aging. Thereafter, the swelled product is adjusted in viscosity by adding and mixing water at room temperature, and then the lumps are reduced by aging to form a paste.

In this viscosity adjustment, it is not necessary to set various conditions such as the amount of water and the temperature as in the prior art, but only the amount of water to be added may be set. For example, as shown in FIG. 2, since the viscosity of the paste has a downward linear characteristic with respect to the liquid to be added, a desired viscosity can be easily obtained. At this time, instead of using water as a liquid to be added, an aqueous solution of about 2.0% hydroxypropylcellulose (hereinafter referred to as an HPC aqueous solution) is used as a humectant to enhance wettability, speed up swelling of starch, and facilitate handling. Becomes

By adjusting the viscosity, the basis weight of the separator coated with the paste can be controlled. In the case of the paste having the viscosity characteristics shown in FIG.
A basis weight of about 20 g / m ² can be obtained at about 0 cps.

Further, in adding and mixing the aqueous zinc chloride solution to the starch, as shown in FIG. 3, the mixing flow rate of the aqueous zinc chloride solution with respect to the starch is controlled while stirring the starch, and substantially at a predetermined flow rate. It is preferable to add and mix over 1 minute. For example, 100 parts by weight of Constarch J
And 200 parts by weight of Longum CE-3 are mixed with 360 parts by weight of a 35.5% aqueous zinc chloride solution. At this time,
2 kg of constarch J, 4 kg of longum CE-3,
The aqueous zinc chloride solution is made up to 5.5 liters. When the mixing flow rate of the aqueous zinc chloride solution is controlled and mixed at a predetermined flow rate for one minute, swelling is quickly and sufficiently performed, and the process can immediately proceed to the next step without the need to secure aging.

In addition, preferably, water or an aqueous solution of hydroxypropylcellulose is added to and mixed with the swelled product, as shown in FIG. 3, while stirring the swelled product with water or an aqueous solution of hydroxypropylcellulose. The mixing flow rate is controlled and the mixture is added at a predetermined flow rate for 10 to 15 minutes and mixed. For example, 100 parts by weight of Constarch J and 200 parts by weight of Longum CE-3 are mixed with 360 parts by weight of an aqueous solution of zinc chloride, and swelled, and 11 to 12 liters of water is mixed. When the flow rate of water mixed with the swelling material is controlled and mixed at a predetermined flow rate for 10 to 15 minutes, the water is well dispersed in the swelling material, and the generation of granular lumps is reduced. This reduces the aging time required to reduce lumps. When 11 liters of water were mixed, the viscosity was about 900 cps and the separator basis weight was 25 g /
m ² was obtained, and when 12 liters of water were mixed, the viscosity was about 1600 cps and the basis weight of the separator was 35 g /
m ² was obtained.

In the above-described method for producing a paste, there is no heating step or a step of adding a heated liquid, and all materials of the paste and the temperature environment over the entire production process can be at room temperature. Detrimental effects such as temporal changes in viscosity due to low temperature or temperature change can be eliminated. Further, it is not necessary to use a heating and cooling facility.

Further, since water is added at room temperature after the starch is swollen at room temperature, the starch does not settle in water, and it is not necessary to add a binder for preventing settling. In addition, the stirring operation is minimal, and it is not necessary to constantly stir the entire manufacturing process.

In addition to the above-mentioned HPC aqueous solution, InCl ₃
The same effect can be obtained by using an inhibitor for the purpose of improving the corrosion resistance, potential stability, and discharge performance of the aqueous solution (equalizing the reaction surface of the zinc can). Corrosion can be prevented.

Next, a method for producing a separator coated with the paste obtained by the above-described production method will be described. First, this paste is applied to a separator base paper made of kraft paper at 20 to 80 g / m ² . Apply at basis weight. Then, it is dried at a temperature of 50 to 105 ° C. by passing it through a hot-air drying furnace to obtain a separator for a manganese dry battery. At this time,
Since drying is performed at a relatively low temperature of 50 to 105 ° C. instead of drying at a high temperature of 110 ° C. or higher as in the related art, problems due to overdrying can be prevented.

In order to confirm the effect of preventing the above problems by the separator manufacturing method of the present invention, the drying state and the basis weight of the separator according to the present invention and the separator manufactured by the manufacturing method described in the section of the prior art were respectively changed by changing the drying temperature and the basis weight. , The presence or absence of curl, and the application state were investigated. Regarding the application of the paste produced according to the present invention, only one side (zinc can side) and both sides of the separator base paper are applied.
As expected.

Table 1 shows the results. In the table, regarding the dry state, those with insufficient drying and unevenness were marked as x and those that were good were marked with ○, and the presence or absence of curl was determined as having and not having curled. The coating state was evaluated as x when the coating could not be applied satisfactorily due to insufficient drying or the like.

At a drying temperature of about 45 ° C. or less, all of the above three items caused problems according to the examples manufactured according to the present invention and the conventional examples. In Examples and Examples, good separators having no problems were obtained in a drying temperature range of 50 to 105 ° C., and especially in the case of a basis weight of about 35 g / m ^{2 in} Examples, the separator was flexible when assembled as a manganese dry battery. No defects such as cracks were generated at all, and no problem such as deterioration or deformation occurred even in a high-temperature and high-humidity environment, and an extremely good separator was obtained. On the other hand, when the drying temperature is in the range of about 110 ° C. or more, unevenness in the dried state, curling and cracks are generated, and in the present invention, the drying temperature is 50 to 105 ° C.
It was confirmed that a relatively low temperature was desirable. In addition, the basis weight of the paste based on the separator
It was also confirmed that it can be increased to 0 g / m ² .

Further, in the conventional examples and above, when the drying temperature is in the range of 45 to 105 ° C., the drying state becomes uneven, curls and cracks occur, and the drying temperature is about 1 ° C.
At 10 ° C., only the curl occurs in the conventional example and the conventional example at the drying temperature of about 110 ° C. or more, and the comparative example or the comparative example at the drying temperature of about 160 ° C. or more obtained a relatively good separator. However, the drying time had to be performed more precisely than in the examples, and the process management was complicated.

[0030]

[Table 1] As described above, when the battery characteristics after storage of the R03-type manganese dry battery shown in FIG. 4 employing the separator obtained by the manufacturing method described above were measured, the results shown in Table 2 were obtained.
In all of the storage conditions at the initial stage, after storage at 60 ° C. for 20 days, and after storage at 45 ° C. for 3 months, it was confirmed that the example manufactured according to the present invention had a longer discharge time and was superior to the conventional example. Was. In the table, M.P. , H .; Indicates discharge time and discharge time until the voltage drops to a predetermined end voltage, and 15 ohms 10 M / D indicates that discharge is performed at 15 ohms for 10 minutes per day.

[0031]

[Table 2]

[0032]

As described above in detail, according to the present invention, the production process can be greatly simplified, and the paste material can be used at room temperature without heating, thus making the production extremely simple.

Further, it is not necessary to use an additive such as a binder or a heating / cooling equipment, so that the mass productivity can be greatly improved and the manufacturing cost can be significantly reduced.

Further, it is possible to improve the discharge performance and storage performance of the battery employing the separator using the paste produced by the production method of the present invention. Further, since the drying can be performed at a lower temperature than the conventional one, the manufacturing cost can be reduced.

In addition, an aqueous zinc chloride solution is added to and mixed with the starch by adding an aqueous zinc chloride solution to the starch at a predetermined flow rate for about 1 minute while stirring the starch, thereby mixing the starch quickly and swelling. The swelling time can be shortened sufficiently.

More preferably, in adding and mixing water or an aqueous solution of hydroxypropylcellulose to the swelled product, water or an aqueous solution of hydroxypropylcellulose is added to the swelled product at a predetermined flow rate while stirring the swelled product. By adding and mixing for 15 minutes, water or an aqueous solution of hydroxypropylcellulose is satisfactorily dispersed in the swollen material, so that generation of lumps can be reduced, and the aging time for reducing lumps can be shortened.

[Brief description of the drawings]

FIG. 1 is a chart showing a manufacturing process of a separator for a manganese dry battery according to the present invention.

FIG. 2 is a graph showing a viscosity characteristic of a paste with respect to an amount of an aqueous HPC solution of the paste for coating a separator according to the present invention.

FIG. 3 is a chart showing a production process by controlling a flow rate of a zinc chloride aqueous solution and water.

FIG. 4 is a partially broken longitudinal sectional view of a manganese dry battery employing a separator according to the present invention and a conventional manufacturing method.

FIG. 5 is a chart showing a process for manufacturing a conventional separator for a manganese dry battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Negative electrode zinc can 2 Separator 3 Positive electrode mixture 4 Carbon rod 5 Sealing gasket 6 Positive terminal plate 7 Negative terminal plate 8 Shrink tack label

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihide Izumi 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd. (56) References JP-A-58-100357 (JP, A) (58 ) Surveyed field (Int.Cl. ⁶ , DB name) H01M 2/16

Claims (5)

(57) [Claims] An aqueous zinc chloride solution is added to and mixed with starch to swell the starch, and then the swelled product is mixed with water to form a paste, and the paste is applied to a separator base paper. For producing a manganese dry battery separator. 2. After added and mixed aqueous solution of zinc chloride to the starch to swell the starch, hydroxypropyl this swelling was
A method for producing a separator for a manganese dry battery, comprising mixing an aqueous cellulose solution into a paste and applying the paste to a separator base paper. 3. The method of adding and mixing the aqueous solution of zinc chloride to the starch, comprising adding the aqueous solution of zinc chloride to the starch at a predetermined flow rate for about 1 minute while stirring the starch. A method for producing a separator for a manganese dry battery according to claim 1 or 2. 4. When the water or the aqueous solution of hydroxypropylcellulose is added to and mixed with the swelled product, the water or the aqueous solution of hydroxypropylcellulose is added to the swelled product at a predetermined flow rate while stirring the swelled product. The method for producing a separator for a manganese dry battery according to any one of claims 1 to 3, wherein the mixture is added and mixed over 10 to 15 minutes. 5. The method for producing a separator for a manganese dry battery according to claim 1, wherein the separator base paper coated with the paste is dried in a temperature range of 50 to 105 ° C. Method.