JPH0748375B2 - Separator paper for alkaline batteries - Google Patents

Description

TECHNICAL FIELD The present invention relates to separator paper used in various alkaline batteries such as alkaline manganese batteries, silver batteries, mercury batteries, and zinc-air batteries, and in particular, contact between an anode active material and a cathode active material. It is intended to prevent internal short circuit of the battery due to, and also improve other various characteristics required for the separator paper, and therefore to a more precise and small internal resistance separator paper for alkaline batteries. .

2. Description of the Related Art Usually, in the above alkaline battery, a separator paper for separating the anode active material and the cathode active material is used, and the characteristics required as this separator paper are contact between the anode active material and the cathode active material. It is necessary to prevent internal short-circuiting due to, and to have excellent durability that does not cause shrinkage or deterioration with respect to electrolytic solutions such as potassium hydroxide or depolarizers such as manganese dioxide, and to cause an electromotive reaction. In addition to holding a sufficient amount of electrolytic solution, the internal resistance can be reduced without disturbing the conduction of ions, and the volume occupied when incorporated in the battery is small, and the amount of the bipolar active material can be increased. It is possible.

As conventional separator paper, vinylon fiber (copolymer fiber of vinyl chloride and vinyl acetate) and rayon fiber are mixed and heat-treated by a paper machine dryer or post-processing to partially heat-bond the vinylon fiber. Separator paper in which fibers are bound to each other, or linter pulp, vinylon fibers and cellulose fibers such as rayon fibers are blended,
Polyvinyl alcohol fiber is added as a binder for mixing, and the polyvinyl alcohol fiber is dissolved in water contained in wet paper with a paper machine dryer, and dried, and synthetic fibers such as separator paper and cellulose are bound to each other and cellulose. Mixed paper made of fibers is used.

Further, JP-A-62-154559 discloses an alkaline dry battery in which some or all of the fibers constituting the separator paper are replaced with conventional thick fibers having a fineness of 1 to 3 denier and synthetic fibers having a fineness of 0.8 denier or less. For separator paper, and containing the synthetic fibers and cellulose fibers, the weight ratio is 15:85 ~ 85:
15 separator paper, further double-layered separator paper, one layer of which is a synthetic fiber having a fineness of 0.8 denier or less, and the other layer is made of cellulosic fibers having a fineness of 1.0 denier or more, which is more dense. The structure of the separator paper is disclosed. Further, the applicant, at the time when the addition of mercury was allowed, according to JP-A-54-87824,
As a separator paper with low electrical resistance, which is dense and prevents internal short circuit of both polar active materials, synthetic fiber to make the CSF value of 510-720 ml softly beaten mercerized wood kraft pulp 50% or more. It provides a separator paper obtained by mixing with.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, a separator paper obtained by mixing and mixing such a conventional synthetic fiber and separator fiber has practically no problem in durability against electrolytic solution or depolarizing agent and retaining property of electrolytic solution. ,
Since the separator paper has a large pore size, there is a problem in that it is insufficient in terms of preventing an internal short circuit due to contact between the bipolar active materials. In order to deal with this, when used as a separator, the separator paper is laminated in several layers to reduce the substantial pore diameter, or it is superposed with a separator material having fine pores such as cellophane film or polyethylene porous membrane. Means such as use are adopted.

Also, in an alkaline battery using zinc as the cathode active material,
Conventionally, in order to smoothly carry out the discharge reaction, a means of converting the surface of zinc particles into an amalgam by using mercury as an active material has been used, but it is possible to reduce the amount of mercury used from the viewpoint of preventing environmental pollution due to mercury in recent years. I'm sick. In other words, in Japan, the regulated amount of mercury added was 9.0% for zinc before March 1985, but became 3.0% for zinc after March 1985, and after September 1987 zinc was added. On the other hand, it is 1.0% for AA and AA batteries and 1.5% for AA batteries. for that reason,
For the purpose of reducing the above-mentioned mercury, lead, indium, gallium,
A zinc active material with aluminum added is used, but as a new problem, when the battery is used at a light load, needle crystals of zinc oxide (dendrites) are generated in the separator paper and If this condition continues, there is a risk of an internal short circuit. That is, by reducing the amount of mercury, zinc, which is the cathode active material, is easily corroded, and as a result, zinc oxide crystals having electroconductivity are deposited, and the crystals migrate into the separator paper to produce the bipolar active material. Are electrically contacted with each other to induce an internal short circuit, and the battery capacity is reduced.

On the other hand, in order to prevent the internal short circuit, if the thickness of the separator paper is increased or the number of laminated separator papers is increased, the volume of the separator paper occupying the inside of the battery increases, and the amount of the active material inevitably increases. Will decrease and the battery capacity will decrease. When superposed with a separator material having fine holes such as cellophane film, a thin separator is obtained, which is convenient in terms of battery capacity,
On the other hand, it becomes difficult to insert the separator paper into the battery, and because the cellophane and the separator paper have different dimensional changes in the electrolytic solution, it can be applied to a small separator area such as a button type battery. However, there is a problem that it is difficult to apply it to a cylindrical battery having a large separator area.

Further, as described in JP-A-62-154559, by replacing some or all of the fibers constituting the separator paper with conventional thick denier fibers and using synthetic fibers having a fineness of 0.8 denier or less, the separator In order to densify, the use of synthetic fibers with a small fineness increases the density of the obtained sheet, and the fibers are mutually heat-sealed or bound with a binder. There is a problem that the binding area increases and the electric resistance increases more than the sheet density increases. Further, since the synthetic fiber having a small fineness is expensive, the cost is increased. Further, the above-mentioned Japanese Patent Laid-Open No. 54-87
The denseness of the separator paper obtained by No. 824 is 0.2 to 1.2 seconds / 100 ml in terms of airtightness, and it is possible to effectively prevent internal short circuit at the time when a sufficient amount of mercury was allowed to be added. Yes, it is, but nowadays it is no longer sufficient to prevent internal short circuits, as regulations for lowering mercury levels are tightened. In addition, since the separator paper obtained when the CSF value is made small and beaten to a high degree has a high density and has a high electric resistance, the above-mentioned JP-A-54-8782 is used.
In No. 4, the degree of beating is as mild as CSF value of 510 to 720 ml. Therefore, in order to prevent the internal short circuit and obtain the above-mentioned airtightness, it was necessary to blend mercerized wood kraft pulp at 50% by weight or more.

Therefore, the present invention solves various problems that such conventional alkaline battery separator paper has, and densifies the separator paper to bring the bipolar active material into contact with the separator paper, or to reduce mercury. It is an object of the present invention to obtain an alkaline battery separator paper which can prevent an internal short circuit due to a conductive zinc oxide crystal and can maintain battery capacity while keeping electric resistance low.

Means for Solving the Problems The present invention, in order to achieve the above object, is a separator paper for alkaline batteries, which is made by mixing beaten alkali-resistant cellulose fibers and synthetic fibers, wherein the alkali-resistant cellulose fibers are 10 % To 50% by weight, and the degree of beating of the alkali-resistant cellulose fiber is CSF.
Is in the range of 500 ml to 0 ml in the range of separator paper for alkaline batteries, characterized in that a part or all of the alkali resistant cellulose fibers are mercerized fibers of natural cellulose fibers, while A part or all of the alkali resistant cellulose fiber is mercerized from softwood wood pulp to form a separator paper for an alkaline battery.

Further, some or all of the alkali resistant cellulose fibers are mercerized fibers of hardwood wood pulp, and some or all of the alkali resistant cellulose fibers are esparto pulp, pineapple pulp, manil hemp pulp and sisal pulp. At least one selected
It is characterized by being a mercerized fiber of the seed.
Further, a part or all of the alkali-resistant cellulose fiber is a polynosic rayon fiber, and a part or all of the synthetic fiber is a polyethylene synthetic pulp, which is a separator paper for an alkaline battery.

Further, in the present invention, a beaterable alkali-resistant cellulose fibers and synthetic fibers are mixed with a binder, and a separator paper for an alkaline battery formed by binding the alkali-resistant cellulose fibers from 10% by weight. The alkali-resistant cellulose fiber is contained in an amount of 50% by weight, and the beating degree of the alkali-resistant cellulose fiber is in the range of 500 ml to 0 ml in terms of CSF, which is a separator paper for alkaline batteries. Part or all is a fiber obtained by mercerizing hardwood wood pulp, and part or all of the synthetic fiber is vinylon fiber. Further, the binder is polyvinyl alcohol powder, or the binder is polyvinyl alcohol fiber, which is a separator paper for an alkaline battery.

According to the present invention having the above-described structure, the obtained separator paper is one in which fibrillated fine cellulose fibers are contained in the separator paper, and the airtightness is excellent in the denseness, When used as separator paper for alkaline batteries, the effect of preventing internal short-circuiting due to contact between both electrode active materials and the internal short-circuiting due to conductive zinc oxide crystals associated with low mercury content is low, and the electrical resistance is low, and It is possible to obtain a separator paper capable of increasing the filling amount. Further, compared to separator paper using fine denier synthetic fibers, synthetic fibers do not absorb electrolyte at all, whereas cellulose fibers are fibers that absorb electrolyte and can contribute to conductivity. Even if the same fine denier synthetic fiber is used, the separator paper according to the present invention has a small area which does not contribute to the conductivity of the binding portion due to the presence of fine cellulose fibers around the synthetic fiber, and thus has a high density. The electrical resistance can be kept low even as an excellent airtight separator paper.

Furthermore, when mercerized cellulose is beaten and used, it retains a sufficiently short ion conduction path even if it has a relatively high density, and has extremely excellent compactness and uniformity. The compactness can completely prevent an internal short circuit, and the sufficiently short ion conductive path can increase the ion conductivity to reduce the electric resistance. Further, due to the mercerization, the cross section of the fiber is changed from a flat cross section to a circular cross section, and the ion conductivity is improved. Further, since the fibers are hardened by the mercerization, the fibers are beaten in a free state by beating, and the fibers are dispersed smaller, so that it is difficult to increase the density even if the beating degree is increased.

EXAMPLES Various examples of the separator paper for alkaline batteries according to the present invention will be described below.

First, the cellulose fiber used in the present invention is a beating fiber having excellent alkali resistance, and examples of such a fiber include softwood wood pulp, hardwood wood pulp, esparto pulp, pineapple pulp, manila hemp pulp and sisal pulp. A mercerized pulp obtained by subjecting natural cellulose fibers such as the above to a cold alkali treatment is used. In particular, mercerized pulp of hardwood wood pulp, esparto pulp, and pineapple pulp has a small fiber diameter, and is therefore suitable because the airtightness of the separator paper can be increased.

The above-mentioned mercerization treatment means that the above natural cellulose fiber is added to a cold alkali, for example, 40% potassium hydroxide solution in an amount of 3 to
The fibers are swollen by immersing them for 4 hours and washed well to remove hemicellulose, which is easily disintegrated in the pulp, and at the same time, the flat cross section of the fibers is circularized.

Also, the α-cellulose content of linter pulp is 97%.
The above pulps have excellent alkali resistance and can be used without mercerization. Furthermore, even in regenerated cellulose fibers, regenerated cellulose fibers such as polynosic rayon fibers and cupra fibers cause fibrillation by beating, and therefore can be used in the present invention.

Next, beaten the alkali-resistant cellulose fiber,
After the cellulose fibers are fibrillated into fine fibers, the beaten cellulose fibers are mixed with synthetic fibers, and if necessary, binders such as polyvinyl alcohol fibers are added and mixed to carry out mixed papermaking.

The content and beating degree of the cellulose fiber can be set to an appropriate value according to the characteristics required for the battery separator, but in the case of the present invention, the content of the cellulose fiber is 10% by weight to 50% by weight. So that it is in the range of%,
Moreover, the beating degree is CSF (Canadian Standard Freeness, Canadian St
Andard Freeness) is set to be in the range of 500 ml to 0 ml. That is, the one containing 50% by weight or more of cellulose fibers swells remarkably when impregnated with an electrolytic solution, and the separator volume when incorporated in a battery becomes large because the thickness of the cellulose fibers increases, which inevitably results. The amount of active material has to be reduced, resulting in a decrease in battery capacity. When the content of cellulose fibers is 10% by weight or less, the liquid retaining property of the electrolytic solution when incorporated in the battery becomes insufficient, and the internal resistance of the battery increases.

If the beating degree of cellulose fiber exceeds 500 ml,
The fibrillation of the fibers by beating is insufficient, and only separator paper with poor compactness as in the past can be obtained, and such separator paper containing less beating cellulose fibers is The degree of swelling will increase. Conversely, if the beating degree of the cellulose fiber is increased and CSF reaches 0 ml and the cellulose fiber is further beaten, the cellulose fiber will flow out from the paper making net during paper making, resulting in a decrease in yield. Bring results.

That is, in today's strict regulations for lowering mercury, internal short circuits cannot be prevented by the denseness of Japanese Patent Laid-Open No. 54-87824. Therefore, in order to realize the tightness (airtightness) that can prevent an internal short circuit even under today's low mercury conditions, the CSF value is 500 ml to 10 ml.
It is necessary to be highly beaten. On the other hand, if the content of such highly beaten alkali-resistant cellulose fibers exceeds 50% by weight, the airtightness becomes too high and the electrical resistance becomes too high to be suitable for use.

Therefore, in the present invention, even in today's low-mercury environment, effective prevention of internal short circuit, giving appropriate liquid retention to the separator paper, and in view of keeping the swelling degree low, the inclusion of alkali-resistant cellulose The amount is 10% to 50% by weight,
A beating degree of 500 ml to 0 ml is suitable. Particularly preferably, the content is 15% to 40% by weight, and the beating degree is 400 ml to 5%.
A range of 0 ml is appropriate.

The synthetic fiber used in the present invention is preferably a fiber having excellent alkali resistance, and as such a synthetic fiber, in addition to ordinary synthetic fibers such as polypropylene fiber, polyethylene fiber, polyamide fiber, vinylon fiber and vinylon fiber, polypropylene- There are composite fibers such as polyethylene composite fiber, polypropylene-polyethylene vinyl acetate composite fiber and polypropylene-polyethylene vinyl alcohol composite fiber, and synthetic pulp such as polypropylene synthetic pulp and polyethylene synthetic pulp. Among these synthetic fibers, the composite fiber is a fiber which is bound to each other by a dryer of a paper machine, and a separator paper having sufficient strength can be obtained only by mixing with cellulose fiber to make a paper, which is preferable. Further, synthetic pulp is a fibrillated synthetic resin, is a pulp-like material having fine branched fibrils, and when mixed with beaten cellulose fibers, the denseness of the obtained separator paper can be further improved. it can.

Incidentally, using polyamide fiber, vinylon fiber or the like as a synthetic fiber, when mixed with cellulose fiber, usually polyvinyl alcohol fiber, polyvinyl alcohol powder and the like binder is added and mixed to form a separator paper, but the addition amount of the binder is It is preferably in the range of 5% to 20% by weight. If the addition amount of the binder is less than 5% by weight, the strength of the separator paper decreases, which is not preferable. On the other hand, if the amount of the binder added exceeds 20% by weight, not only the fibers are bound to each other, but also the binder adheres in the interstices between the fibers in a film form, which undesirably increases the electric resistance. Since the polyvinyl alcohol powder has a smaller particle size than the polyvinyl alcohol fibers, it can be uniformly distributed between the synthetic fibers and the cellulose fibers, and thus even after being dissolved and dried by a paper machine dryer and acting as a fiber binder. Since it is evenly distributed among the fibers and does not easily adhere to the fiber gaps in a film shape, the electrical resistance can be made smaller than that of separator paper using polyvinyl alcohol fibers.

Further, in the production of the separator paper according to the present invention, one or more of the cellulose fibers are dispersed in water and beaten to a predetermined CSF with a beater or a double disc refiner for making paper, and then the above-mentioned synthesis is performed. One or more of the fibers are mixed, and further, a binder such as polyvinyl alcohol fiber or polyvinyl alcohol powder is added and mixed as a raw material to impart strength to the separator paper, and the mixture is used as a raw material. A general papermaking method such as papermaking with a paper machine such as a mesh paper machine is used.

Hereinafter, various concrete examples for producing the separator paper for an alkaline battery according to the present invention and comparative examples for producing a separator sheet of a conventional example will be shown for comparison with this example.

[Example 1] 25 parts by weight of mercerized hardwood wood pulp was beaten to CSF 200 ml with a double disc refiner, and then 65 parts by weight of vinylon fibers (0.5d x 2 mm) and 10 parts by weight of polyvinyl alcohol fibers were added and mixed. And used as raw material. Paper is made from this raw material on a circular net paper machine and has a thickness of 100 μm and a basis weight of 32.5 g / c.
m ³ of separator paper was obtained.

Example 2 15 parts by weight of linter pulp was beaten with a beater to 30 ml of CSF, and then 70 parts by weight of vinylon fiber (1d × 3 mm) and 15 parts by weight of polyvinyl alcohol fiber were added and mixed to obtain a raw material. Paper is made from this raw material with a cylinder paper machine, and the thickness is 138 μm.
A separator paper having a basis weight of 35.8 g / cm ³ was obtained.

[Example 3] After 30 parts by weight of polynosic rayon fiber (2d x 8 mm) was beaten with a beater to 400 ml of CSF, vinylon fiber (1 d x 3 m)
m) 60 parts by weight and 10 parts by weight of polyvinyl alcohol fiber were added and mixed to obtain a raw material. This raw material was subjected to paper making with a cylinder paper machine to obtain a separator paper having a thickness of 115 μm and a basis weight of 31.9 g / cm ³ .

Example 4 30 parts by weight of mercerized softwood wood pulp was beaten to 380 ml of CSF with a double disc refiner, and then 50 parts by weight of vinylon fiber (0.5d × 2 mm) and 20 parts by weight of polyvinyl alcohol powder were added and mixed. Used as raw material. Paper is made from this raw material with a circular net paper machine and has a thickness of 118 μm and a basis weight of 32.2 g / cm ^3.
To obtain a separator paper.

[Example 5] 40 parts by weight of mercerized softwood wood pulp was beaten to 480 ml of CSF with a double disc refiner, and then polypropylene-polyethylene vinyl acetate composite fiber (2d x 5 m
m) 60 parts by weight were added and mixed to obtain a raw material. This raw material was subjected to papermaking with a cylinder paper machine to obtain a separator paper having a thickness of 254 μm and a basis weight of 48.3 g / cm ³ .

[Example 6] After 45 parts by weight of mercerized softwood wood pulp was beaten to CSF of 160 ml with a double disc refiner, 25 parts by weight of polyethylene synthetic pulp and 30 parts by weight of polypropylene-polyethylene composite fiber (0.7d x 5 mm) were added. It was mixed and used as the raw material. Paper thickness of this raw material is made with a cylinder paper machine
A separator paper with 123 μm and a basis weight of 34.4 g / cm ³ was obtained.

[Comparative Example 1] 25 parts by weight of mercerized hardwood wood pulp after beating (CSF6
To 80 ml), 65 parts by weight of vinylon fiber (0.5d × 2 mm) and 10 parts by weight of polyvinyl alcohol fiber were added and mixed to obtain a raw material. This raw material was made into paper with a circular net paper machine and had a thickness of 110 μm.
A separator paper corresponding to Example 1 having a basis weight of 32.1 g / cm ³ was obtained.

[Comparative Example 2] 15 parts by weight of lightly beaten linter pulp (580 ml of CSF)
70 parts by weight of vinylon fiber (1d × 3 mm) and 15 parts by weight of polyvinyl alcohol fiber were added and mixed to prepare a raw material. Papermaking this raw material with a circular net paper machine, thickness 140μm, basis weight 35.7g
A separator paper of / cm ³ corresponding to Example 2 above was obtained.

Comparative Example 3 To 30 parts by weight of viscose rayon fiber (0.7d × 5 mm), 60 parts by weight of vinylon fiber (1d × 3 mm) and 10 parts by weight of polyvinyl alcohol fiber were added and mixed to prepare a raw material. This raw material was subjected to paper making with a cylinder paper machine to obtain a separator paper having a thickness of 118 μm and a basis weight of 31.5 g / cm ³ corresponding to Example 3 above.

Regarding the separator papers obtained in Examples 1 to 6 and Comparative Examples 1 to 3, the CSF (ml), thickness (μm), basis weight (g / cm ³ ), and tensile strength ( kg), airtightness (second / 100 ml), swelling degree (%) and electric resistance (mΩ) were measured. The measuring method and device are as follows.

(1) Thickness Thickness was measured at 5 points on the obtained separator paper with a diamond thickness gauge, and the average value thereof was used.

(2) Basis weight and tensile strength For the basis weight, the method specified in JIS P 8124 was adopted, and for the tensile strength, the method specified in JIS P 8113 was adopted.

(3) Airtightness Airtightness is JIS P 8117 (permeability test method for paper and board)
A circular diaphragm with a diameter of 6 mm is attached to the lower test piece mounting part of the B type measuring instrument of No. 2, and the time required for 100 ml of air to pass through the circular surface of the separator paper with a diameter of 6 mm sandwiched between the diaphragm (second / 100 ml) was measured.

(4) Degree of swelling Degree of swelling is calculated by using the following formula to measure the thickness of the separator paper before and after soaking it in a 40% KOH aqueous solution for 30 minutes by stacking two sheets of separator paper. It was

Swelling degree (%) = (thickness after soaking-thickness before soaking) ÷ thickness before soaking × 100 (5) Electric resistance Insert the separator paper between the parallel platinum electrodes at an interval of 3 mm. Then, the increase in the electrical resistance between the electrodes due to this insertion was taken as the electrical resistance of the separator paper. In addition, 40% KOH aqueous solution is used as the electrolyte, and the electric resistance between the electrodes is 1000H.
It was measured with an ESR meter at a frequency of z.

Table 1 shows the results of measuring the separator paper of each of the examples and comparative examples using such a measuring means.

As shown in the measurement results of Table 1, the separator paper according to the present invention has a significantly higher airtightness than the conventional separator paper, while the electrical resistance and the swelling degree are small. For example, Example 1 is a separator paper containing 25 parts by weight of mercerized cellulose fibers beaten to 200 ml of CSF, which corresponds to Comparative Example 1 using conventional unbeaten cellulose fibers. The airtightness of Example 1 is 1.2 seconds, which lacks in tightness and is apt to cause an internal short circuit, whereas the airtightness of Example 1 is 10.7 seconds, and the airtightness is significantly enhanced. The precision is improved. The electrical resistance of Comparative Example 1 was 18.5 mΩ, while the electrical resistance of Example 1 was improved to 17.9 mΩ, and the internal resistance can be reduced. Further, the swelling degree is 26 in Comparative Example 1.
%, Whereas Example 1 has a small value of 14%, and alkali resistance can also be improved.

Next, when comparing Example 2 in which the same raw material was beaten up to 30 mL of CSF as in Comparative Example 2 in which the degree of beating was 580 ml of CSF, the airtightness of Comparative Example 2 was 1.9 seconds, which is higher than that of Comparative Example 1 that was not beaten. It is slightly improved but not enough, and it is necessary to beat to less than 500 ml of CSF. And even if the same raw material was used, the airtightness was 15.8 when beaten up to 30 ml of CSF as in Example 2.
Secondly, the electric resistance and the degree of swelling are also small.

From the above measurement results, the separator paper according to the present invention has a high airtightness and is therefore excellent in denseness, and when used as a separator paper for an alkaline battery, an internal short circuit due to contact between the two electrode active materials is prevented, and further low mercury content is obtained. It is clear that the separator paper has a large effect of preventing an internal short circuit due to the electroconductive zinc crystal due to the increase in the temperature and has a small electric resistance.

Further, the beating reduces the degree of swelling in the electrolytic solution, thus improving the alkali resistance of the separator paper.

Next, using the separator papers obtained in Examples 1 to 6 and Comparative Examples 1 to 3, trial manufacture of an alkaline manganese battery (LR-6) using a low mercuricized zinc active material was carried out. Table 2 shows the results of measuring the discharge voltage of the battery before and after the discharge test for 100 hours at 75Ω.

As is clear from Table 2, in the case of the batteries of Comparative Examples 1, 2 and 3 using the conventional separator paper, the discharge voltage after the test was all 0.9.
In contrast to V or less, the batteries using the separator papers of Examples 1 to 6 according to the present invention have a discharge voltage of 1.00.
It was confirmed that V or more remained. That is, Comparative Examples 1 to
In the case of No. 3, since the separator paper was not sufficiently dense, the battery caused an internal short circuit due to the conductive zinc oxide crystals generated by the use of the low mercurized zinc active material. In this case, it can be considered that the conductive zinc oxide crystals were sufficiently blocked by the separator paper to prevent the internal short circuit of the battery.

Incidentally, the separator paper containing the finely beaten cellulose fibers like the separator paper according to the present invention is different from the separator paper in which the conventional unbeaten cellulose fibers and synthetic fibers are mixed, by the action of the electrolytic solution. It also seems to be prone to deterioration. However, as shown in the measurement results of Table 2, the separator paper obtained when the cellulose fiber having excellent alkali resistance among the cellulose fibers is beaten and used as in the present invention, is stored in the electrolytic solution for a long time. No deterioration was observed, but rather the degree of swelling in the electrolytic solution was reduced as shown in Table 1, so that the alkali resistance was improved.

Effects of the Invention As described in detail above, the alkaline battery separator paper according to the present invention is an alkaline battery separator paper obtained by mixing beaten alkali-resistant cellulose fibers and synthetic fibers, wherein the alkali-resistant cellulose is used. 10 fibers
It is contained in the range of 50% by weight to 50% by weight, and the beating degree of the alkali-resistant cellulose fiber is CSF value of 500 ml to 0 ml.
In the configuration of the alkaline battery separator paper in the range of, since the basic configuration is that a part or all of the alkali-resistant cellulose fiber is a mercerized fiber of natural cellulose fiber, the action and effect described below. Be brought. That is, since the pore size of the obtained separator paper is small, the fibers are densified and the airtightness of the separator paper is kept high. A short circuit can be effectively prevented. Further, when used as a separator paper, the number of laminated separator papers can be reduced, so that the battery capacity can be increased.

Further, it is possible to provide a separator paper which has a large effect of preventing an internal short circuit due to the conductive zinc crystal accompanying a reduction in mercury and has a small electric resistance. In addition, the alkaline battery prototyped using the low mercuricized zinc active material using the obtained separator paper, the conductive zinc oxide crystals are sufficiently blocked by the separator paper, the internal short circuit of the battery is prevented. The great effect that the discharge voltage of the battery after a long-term discharge test can be kept high is obtained. Furthermore, when beating and using the mercerized cellulose fiber, even if it has a relatively high density, it still retains a sufficiently short conductive path for ions, and has extremely excellent compactness and uniformity. Therefore, the compactness can completely prevent the internal short circuit, and the sufficiently short ion conductive path can enhance the ion conductivity and reduce the electric resistance. Also, it is easy to insert the separator paper into the battery,
It has the advantage that it is not affected by the size of the separator area in the battery.

Claims (11)

[Claims] 1. A separator paper for alkaline batteries, which comprises a mixture of beatenable alkali-resistant cellulose fibers and synthetic fibers, the alkali-resistant cellulose fibers being 10% by weight to
A separator paper for alkaline batteries, characterized in that it is contained in an amount of 50% by weight, and that the degree of beating of the alkali-resistant cellulose fiber is in the range of 500 ml to 0 ml in terms of CSF value. 2. The separator paper for an alkaline battery according to claim 1, wherein a part or all of the alkali resistant cellulose fibers are mercerized fibers of natural cellulose fibers. 3. The separator paper for alkaline batteries according to claim 1, wherein a part or all of the alkali-resistant cellulose fiber is a mercerized fiber of softwood wood pulp. 4. The separator paper for alkaline batteries according to claim 1, wherein a part or all of the alkali-resistant cellulose fibers are mercerized fibers of hardwood wood pulp. 5. A part or all of the alkali-resistant cellulose fiber is esparto pulp, pineapple pulp,
The separator paper for alkaline batteries according to claim 1, wherein the fiber is a mercerized fiber of at least one selected from Manila hemp pulp and sisal pulp. 6. The alkaline battery separator paper according to claim 1, wherein a part or all of the alkali resistant cellulose fibers are polynosic rayon fibers. 7. The separator paper for alkaline batteries according to claim 1, wherein a part or all of the synthetic fiber is polyethylene synthetic pulp. 8. A separator paper for an alkaline battery, which is prepared by mixing beaten alkali-resistant cellulose fibers and synthetic fibers with a binder and binding them, wherein the alkali-resistant cellulose fibers are contained in an amount of from 10% by weight. A separator paper for alkaline batteries, characterized in that it is contained in an amount of 50% by weight, and that the degree of beating of the alkali-resistant cellulose fiber is in the range of 500 ml to 0 ml in terms of CSF value. 9. The alkali resistant cellulose fibers are partially or wholly mercerized from hardwood wood pulp, and the synthetic fibers are partially or wholly vinylon fibers. The separator paper for alkaline batteries described above. 10. The separator paper for alkaline batteries according to claim 8, wherein the binder is polyvinyl alcohol powder. 11. The separator paper for alkaline batteries according to claim 8, wherein the binder is polyvinyl alcohol fiber.