JPS59138058A - Separator for storage battery - Google Patents

Abstract

PURPOSE:To enable a separator with good acid resistance to be manufactured without any necessity of complicate processes by sticking and tangling together large-diameter glass fiber and small-diameter glass fiber, which are made of silicate glass containing alkali and which are mixed in a specified ratio, by a wet method without using any adhesives. CONSTITUTION:A separator for a storage battery is prepared by sticking and tangling together large-diameter glass fiber and small-diameter glass fiber which have the composition of silicate glass containing alkali by a wet method without using any special adhesives. The large-diameter glass fiber has a mean diameter of 13-30mu (preferably 15-25mu) and the small-diameter glass fiber has a mean diameter of below 3mu (preferably 0.6-1.5mu). The proportion of the large- diameter fiber to the total amount of both fibers is adjusted to 20-80wt% (preferably 40-80wt%).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a separator for a storage battery, and more particularly to a separator for a lead-acid battery mainly composed of glass fiber.

BACKGROUND ART Conventionally, a separator for storage batteries has been used in which a so-called glass mantle made by interlacing glass fibers having an average diameter of 1 s-isμ and a microporous separator are laminated together. However, this separator requires a complicated process of manufacturing the glass mantle and the microporous separator separately and pasting them together, and has the disadvantage that the manufacturing cost is relatively high. As an integrated separator that does not require such a bonding process, for example, 50 parts by weight of glass fiber with a fiber diameter of /μ or less (for example, 0.3 μ) is used in JP-A-3-3-32. , the fiber diameter is 10-30μ (for example //μ
A separator for a storage battery is described, which contains glass fibers of 5 parts by weight and 5 parts by weight of natural cellulose fibers intertwined with each other. However, this separator did not have very good acid resistance, so there was a limit to how long the life of a storage battery using this separator could be extended, and the manufacturing cost of the separator was also not very low.

The present invention aims to eliminate the drawbacks of conventional separators for storage batteries and to provide a separator for storage batteries that can be manufactured without the need for complicated processes, has excellent acid resistance, and is inexpensive to manufacture. purpose.

That is, the present invention has an average diameter of 73 to 30μ and a diameter of 3 to 100μ.
It consists of large-diameter glass fibers with an average length of mm and small-diameter glass fibers with an average diameter of 3μ or less. The large-diameter glass fibers and the small-diameter glass fibers both have the composition of alkali-containing silicate glass, and they are bonded and intertwined with each other during wet papermaking without a special adhesive. This is a separator for storage batteries.

The storage battery separator of the present invention is composed of large-diameter glass fibers and small-diameter glass fibers.
Average diameter of 3-30μ, more preferably /3-, . 25
It has an average diameter of μ and an average length of 3 to 100 mm. When the diameter of the large fiber is smaller than 73 μ, the productivity of the fiber is low and the cost is high; on the other hand, when it is larger than 30 μ, the flexibility of the separator is too small, making it difficult to assemble the storage battery. Papermaking becomes difficult. Large-diameter fibers are made by cutting continuous spun glass fibers into 3 to 100 pieces using a cutter.
Obtained by cutting into lengths of mm. If the cutting length is less than 3 mm, the cutting cost will increase, and the rate of loss due to the cutting falling off with water from the perforated conveyor net during papermaking will increase, which is undesirable. If the paper is cut into lengths, it becomes difficult to uniformly disperse the paper into water for papermaking, which is not preferable.

The small diameter glass fiber used is less than 3μ, preferably 0
．． ~/, with an average diameter of μ. Small diameter glass fibers with an average diameter greater than 3 microns are not preferred since they increase the maximum through hole diameter of the separator and risk causing a short circuit between the C1 battery electrodes. However, glass fibers with an average diameter that is too small are expensive to manufacture, so it is preferable that the diameter is 0168 or more. This small-diameter glass fiber is manufactured by the FA method, centrifugation method, or other so-called short glass fiber manufacturing method, and usually has an average length of q to 3 Q mm.

The mixing ratio of the large-diameter glass fibers and the small-diameter glass fibers constituting the separator of the present invention is such that the large-diameter fibers are 20 to 0% by weight, preferably 0 to 0% by weight, based on the combined amount of both fibers. %. If the proportion of large-diameter fibers is less than 20%, the mechanical strength of the separator decreases and manufacturing costs increase due to an increase in the amount of small-diameter fibers, which is not preferable.

On the other hand, if the amount of large-diameter fibers exceeds go %, this is not preferable because it causes a decrease in the liquid retention capacity of the separator and a deterioration in the liquid absorption.

Both the large diameter glass fibers and the small diameter glass fibers of the separator of the present invention have an alkali-containing silicate glass composition. When these glass fibers are used to manufacture separators by wet papermaking, the alkali and phosphor components in the glass fibers probably react with water for dispersion, forming a water glass layer on the surface of the glass fibers. The water glass layer acts as an adhesive and bonds the glass fibers together. Therefore, organic fibers, binders, etc., which were conventionally required for manufacturing separators, are not required at all in the present invention, and the separators of the present invention do not contain organic fibers, resin binders, or other special adhesives.

These adhesives weaken the acid resistance of the separator and therefore the separators of the present invention have superior acid resistance compared to conventional separators.

Preferable conditions for forming the adhesive layer during papermaking are as follows. A large-diameter glass fiber and a small-diameter glass fiber, both of which have an alkali-containing silicate glass composition, are dispersed for a certain period of time, e.g., s-, 2°, in water to which nitric acid has been added to maintain the pH value at 2 to 3. I'll let it happen. During this time, an adhesive layer is formed on the surface of the glass fiber, and this glass fiber is made into paper and then heated to a predetermined temperature, e.g.
By heating to "c", the intertwined large diameter glass fibers and small diameter glass fibers are bonded to each other by a strong adhesive layer.The large diameter glass fibers and the small diameter glass fibers have the same glass composition. Although it is not necessary to use the glass, an alkali-containing silicate glass composition having good acid resistance is used.

The degree of acid resistance is J-5Q-2 in the state of glass fiber.
J! Desirably, the weight loss when measured according to 0.2 is 2% or less. Glass fibers that easily form an adhesive layer on the glass fiber surface during the papermaking process and have excellent acid resistance have a silicic acid (SiO2) component of O~7j% by weight, and an alkali component R20 (Na20 + 20%). gold side) is g ~, 20%, where 51020R20
is 75 to 90%, and other components that may be included include, for example, Ga, Cr M';' O+ B 2
03.

It is preferable that the glass be made of an alkali-containing silicate glass containing at least seven types, such as Al2O3+ Zn○ and Fe2O3. Examples of preferred alkali-containing silicate glasses are shown in Table 7.

The separator of the present invention differs depending on the type and dimensions of the storage battery in which it is incorporated, but usually has a thickness of O.S-5mm and a thickness of 0.5mm. /! It has a density of r ~0.2/9/Cm3.

Next, the present invention will be explained with reference to examples.

It has the composition of C glass in Table 7 and has an average diameter of 79μ.
A long glass fiber is spun using a cutter, and the long fiber is cut into a length of 2 Q mm using a cutter to obtain a large diameter glass fiber. In addition, short glass fibers having the composition of glass A shown in Table 7, having an average diameter of 0, gμ, and an average length of 9 mm are produced by the FA method to obtain small-diameter glass fibers. Both of these glass fibers are combined with 100 parts by weight of water to give O,
P of the water is added in the proportion of S parts by weight and at the mixing ratio shown in Table 2, stirred and dispersed uniformly, and further sulfuric acid is added to reduce the P of the water.
Maintain H at 3.0 and continue stirring for approximately 70 minutes.

Thereafter, papermaking was carried out and the material was heated to 100°C to obtain a mat-like separator plate for storage batteries. It was observed that the large diameter and small diameter glass fibers constituting this separator were bonded to each other by water glass formed on the surface thereof.

These separators have thicknesses and densities as shown in Table 2.

It had tensile strength, liquid absorption, liquid holding power, electrical resistance, acid resistance, and maximum pore size.

The methods for measuring these characteristic values and the average diameter and average length of the fibers are as follows.

(1) Thickness: 20 Kg/C1m in the thickness direction of the sample
Table 7 of 2] 3 Measured under pressure.

(J Engineering SC-, 220, 2) (2) Density Area of sample 100m x 100m (S) 2
0 to 9 loads! When T is the thickness of the sample when (W) is added, it is expressed as a value given by the formula: W/(sxT)<9/am3).

(3) Tensile strength width: 10 It is expressed as the value of the external force (K) when pulling both ends of a tram sample and causing it to break.

(4) Liquid absorption rate Hold the sample vertically and place the lower part with a specific gravity of 1.
It is expressed as the distance m < mm (7 minutes) that the dilute sulfuric acid rises per minute when immersed in a dilute sulfuric acid solution.

(5) Liquid retention property The weight W2 of the sample containing water when the sample is soaked with water until it is saturated and the sample is hung until ice no longer drips, and the weight W2 of the sample when it does not contain water. Determine Wl, /(7(7X (W2-Wl)/W
Expressed as a value of 2 (%).

(6) Electrical resistance Test cell with a window area of 5drn2 (
The voltage drop v2 was measured by passing a DC current of /A between multiple electrodes of J Engineering S Cr5t3), and the voltage drop v1 was measured when dilute sulfuric acid was added without setting the sample. - Calculate S/n (Vl) and use it as the electrical resistance (Ω・dm2/piece).

(7) Acid resistance Weight Wl (Durham) dry sample in g.

1.2Q.

The sample was immersed in a dilute sulfuric acid solution kept at °C for 5 hours, then washed and dried, and its weight W2 (grams) was measured. Expressed as weight loss (%) calculated by /W1.

The smaller this value, the better the acid resistance. be.

(8) Average diameter Approximately /
It is calculated by taking 20 fibers from each fiber, measuring their diameters using a microscope, and taking the average value of these.

(9) Average length 60 taken out from the above average diameter measurement
The length of the book fibers is measured and expressed as the average value.

For comparison, the average diameter is //μ and the average length is 2Qmm.

C glass composition of 70% glass fiber (weight %, same hereinafter), average diameter 3.5 μ, average length /, 2 mm.

A glass fiber composition of 5% and an average diameter of 0 μm,
Average length 9 mm, glass fiber qO% of A glass composition,
A separator consisting of a link ~S% (comparative example/) and an average diameter of 79μ, an average length of −2 (7 mm + O) and a glass fiber IO% of the glass composition of Table C and an average diameter of 2Sμ,
Average length 77mm, 70% glass fiber of A glass composition, average diameter O0gμ, average length 9mm.

A separator consisting of 20% glass fiber of glass composition (
Comparative Example 2) was produced by the papermaking method in the same manner as in the Examples, and its properties are shown in the table below. As can be seen from the table, the separator of the present invention has superior acid resistance compared to that of the comparative example. Furthermore, the larger the diameter of the glass fibers that make up the separator, the cheaper the manufacturing cost, but the glass fibers that make up the separator of the present invention have a larger diameter than the glass fibers of conventional separators. Therefore, the separator of the present invention can be manufactured at a lower cost than in the past.

Claims (2)

[Claims] (1) Consists of large-diameter glass fibers having an average diameter of 73 to 30μ and average length of 3 to 100mm, and small-diameter glass fibers having an average diameter of 3μ or less; With respect to the total amount of fiber,
? The large-diameter glass fiber and the small-diameter glass fiber both have the composition of alkali-containing silicate glass, and are bonded to each other without a special adhesive by wet paper forming. Intertwined battery separators. (2) The large-diameter glass fiber and the small-diameter glass fiber have an average diameter of /j~2Sμ and O1~75μ, respectively, and the large-diameter glass fiber has an average diameter of l1oep-Zμ with respect to the total amount of it and the small-diameter glass fiber. A separator for a storage battery according to claim 5, wherein the separator is contained in an amount of 0% by weight.