JPS62252064A - Separator for storage battery - Google Patents

Abstract

PURPOSE:To increase electrolyte retantion capacity and electrlyte absorbing capacity in addition to high strength and hardness by bonding glass fibers with water-glass adhesive. CONSTITUTION:Glass fibers mainly consist of fine glass fibers having a mean diameter of 2mum or less, and contain 0-35wt% thick glass fibers having a mean diameter of 10-30mum, and 0-30wt% medium-fine glass fibers having a mean diameter exceeding 2mum but less than l0mum. A preferable mean length of the fine glass fibers is 7-50mm and particularly 10-40mm. Alkali-containing silicate glass fiber is preferable as the ingredient. The fine, medium fine, and thick alkali-containing silicate glass fivers are intertwined in a wet-type paper making process, and in addition, bonded each other with water-glass adhesive added in the paper making process. As the water-glass adhesive, an inorganic adhesive containing water-glass is used in addition to water-glass.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a separator for a storage battery, and particularly to a separator for a storage battery mainly composed of glass fiber.

[Prior art] As a separator for storage batteries containing glass fiber,
Various types have already been proposed and put into practical use, but they can be broadly classified into the following three types. That is.

■Mainly made of short glass fibers, ■Mixed and molded short glass fibers and synthetic fibers, ■ Powder is held in short glass fibers.

It is.

Among these, there is a separator made of a mixture of glass am and powder, which is described in Japanese Patent Application Laid-Open No. 58-206046, but although this separator has good liquid absorption properties, However, there are problems in that the powder easily peels off and falls off from the separator, and the tensile strength is also low.

On the other hand, as a separator made by mixing short glass fibers and synthetic fibers,
-22531, JP-A-56-99968, JP-A-5
There are products described in Japanese Patent Publication No. 3-136632 and Japanese Patent Publication No. 58-663, but these have the advantage of being easy to assemble storage batteries due to their high mechanical strength (tensile strength, rigidity, etc.); It has the disadvantages of poor performance and liquid retention, and a short lifespan due to the presence of organic matter in the system.

On the other hand, there are two types of separators mainly made of glass fiber: those that use a binder such as an organic liquid adhesive, and those that do not use such a binder.

[Problem to be solved by the invention 1 Among separators mainly made of glass fiber, those that do not use a binder can freely expand in volume due to their liquid absorption ability, and have excellent liquid retention and absorption properties for electrolyte. This separator is the best in terms of battery characteristics, but because it is shaped simply by the force of water vitrification and entanglement of the glass fiber surface, its strength and hardness are low, making it difficult to assemble batteries using machines. It has the disadvantage of being difficult to withstand and having poor working conditions.

On the other hand, when organic fibers or thermoplastic binders are used, their adhesive effects improve strength and hardness, but they are less hydrophilic than glass, so the liquid retention and absorption properties of the separator are reduced. Deteriorate.

Moreover, with a liquid-soluble binder, it dissolves in the electrolyte,
There is a problem that it causes a decrease in battery performance, and it is not preferable from the viewpoint of oxidation resistance.

[Means for Solving the Problems] The present invention solves the above-mentioned problems of the prior art and provides a separator for storage batteries that has good strength and hardness, and also has excellent liquid retention and liquid absorption properties. The gist of the present invention is a storage battery separator, which is mainly made of glass fiber and is characterized in that glass m/a are bonded together with a water glass adhesive.

The present invention will be explained in more detail below.

Glass ta#n constituting the storage battery separator of the present invention
is mainly composed of small diameter glass fibers with an average diameter of 2 pLm or less, and large diameter glass fibers with an average diameter of 10 to 304 m @0 to 35
It is preferable that the glass fibers of medium and small diameters #IO to 30% by weight and average diameter of more than 2 #Lm and less than 10Lm are contained. It is inexpensive, and the tensile strength of the separator can be improved by using especially large-diameter glass fibers. The preferred average diameter of small-diameter glass fibers is 0.5 to 1.
．． 0 g, m, more preferably 0.6 to 0.9 Bm. When the diameters l, OBme, and jfi increase, the pore diameter of the separator increases, and conversely, when the diameters become smaller than 0.5 μm, the manufacturing cost increases.

The preferable content of this small diameter glass fiber is 60% by weight or more of the glass fiber weight, particularly preferably 65% by weight or more.If the content is less than 60% by weight, the liquid absorbency and liquid retention are improved. This is because they are more likely to lack sex.

Further, the average length of this small diameter glass fiber is preferably 7 to 7.
50 mm, more preferably 10 to 40 mm. If the average length is shorter than 10 mm, the strength of the separator will be reduced, and if it is longer than 50 mm, it will be difficult to uniformly disperse the separator in water during papermaking.

Such small-diameter glass fibers can be manufactured by the FA method (flame method), centrifugation method, or other short glass fiber manufacturing methods.

In addition, in the present invention, glass m! The average diameter of A was determined by taking photographs of three locations on the sample using an electron microscope, and measuring 20 mm at each location.
It is calculated by measuring the diameter of a book fiber to the nearest 0.1 pLm and taking the average fti of these.

When medium-sized glass fibers are used, the preferred average diameter is 2.0 to 5.0 μm, especially 3.0 to 4.0 μm.
It is. In addition, the content is 5.0 to 30 m weight of glass fiber
．． 0% by weight, especially 1O00-25. It is preferable to set the amount of Ofi to %.

By blending glass fibers with medium and small diameters, the amount of small-diameter glass fibers can be reduced, which is advantageous in terms of cost.

In addition, the length of this medium-thin diameter glass fiber is 7 to 50 mm,
Particularly preferred is 10 to 40 mm.

If large diameter glass fibers are used, their preferred average diameter is between 10 and 204 m, especially between 12 and 19 ILm.

In addition, the content is preferably 8 to 35% by weight, especially 10 to 30% by weight of the weight of glass fiber #I. If the average diameter is smaller than 10#Lm, or the content is less than 8% by weight. When the average diameter exceeds 20 mt- or the content exceeds 35 mt, the tensile strength improvement effect becomes smaller.
If the weight exceeds 1 g, the liquid absorption and liquid retention properties of the separator will decrease. The length of this large diameter glass fiber is 5 to 80 mm.
Particularly preferred is 6 to 40 mm.

A suitable range of the composition of the glass fiber will be explained next.

The composition of the glass fibers constituting the separator of the present invention is not particularly limited, but it is preferable to use alkali-containing silicate glass fibers. A water glass-like substance is generated on the surface of the glass fibers, and the adhesiveness of this water glass substance, along with the added water glass adhesive described later, allows the fibers to be bonded together better, increasing the adhesive strength. In the present invention, among alkali-containing silicate glass fibers, those having good acid resistance are preferably used because they are used in storage batteries. The degree of acid resistance is preferably such that the weight loss is 2% or less when measured according to JISC-2202 in the state of glass fibers with an average fiber diameter of 1 m g or less, and the composition of such glass fibers As for 5tO2 of 60-75% and R20 of 8-20% (N & 20, K2O
(5i02+R20 is 75-80%), and in addition, e.g.
aO1M g O, B 203, Al2O2, ZnO1
Examples include those containing one or two types of plugs such as F e 20 :+. An example of a preferable alkali-containing silica M salt glass is shown in Table 1 below.

Table 1 The separator for a storage battery of the present invention is preferably made of alkali-containing silicate glass 1w1 of small diameter, medium diameter, or large diameter having the above composition.
The fibers are intertwined through wet papermaking and bonded together with a water glass adhesive added during the manufacturing process.

In the present invention, in addition to water glass, the water glass adhesive includes an inorganic adhesive containing water glass, specifically rSi
1pap700J is mentioned. The amount of water glass adhesive added varies depending on the composition, average diameter, average length, etc. of the glass fibers, but if it is too small, the effect of improving the strength of the separator through adhesion will be low, and if it is too large, the adhesion will be too strong and absorption will be reduced. Generally, it is preferable that the amount is 1 to 10% by weight in terms of solid content based on the weight of the glass fiber, since it inhibits the swelling property when liquid is applied and deteriorates the liquid absorption property.

In order to manufacture such a separator for a storage battery according to the present invention, a glass fiber paper product is first manufactured.

In this case, glass fibers cut in advance to a predetermined length may be blended in a desired ratio and mixed to form a paper. However, it is advantageous to use the following method, for example.

That is, prepare relatively long glass mm1 of small diameter, medium diameter, and large diameter cut into predetermined lengths manufactured by FA method (flame method), centrifugation method, and other short glass fiber manufacturing methods,
These four diameter fibers are blended in an appropriate ratio and dispersed using a pulper.

Alternatively, the glass fibers may be cut into shorter lengths by an appropriate cutting means while being fed to the paper machine net.

In addition, the cut glass fibers are made into paper on a net, and at that time, it is preferable that the pH inside the refractory machine and/or the pH in the papermaking tank be less than about 3, for example about 2.5. By difficult and/or wet papermaking in an acidic region.

An adhesive layer of wood glass derived from glass fibers is formed on the surface of glass 1a, and then this is heated to a predetermined temperature, e.g.
By heating to 60° C., the glass fibers are bonded together by the water glass on their surface.

That is, if the glass fibers constituting the separator have an alkali-containing silicate glass composition.

Alkaline components and silica components in the miscellaneous glass 1a.

It reacts with water for dispersion in an acidic range of about PH 2.5 to form a water glass layer on the surface of the glass fibers, and this water glass layer acts as an adhesive to firmly adhere the glass fibers to each other.

Normally, the glass fiber paper product wet-formed in this way is dried along a drum dryer to produce a product, but in producing the separator of the present invention, after drying the obtained paper product, or Before drying, a wood glass adhesive is applied to the paper product by a so-called external addition method in which the paper is passed through a water glass adhesive bath, and then heated and dried.

By heating and drying, the glass fibers are firmly bonded by the attached water glass.

Note that the method of adding the water glass adhesive is not limited to the external addition method described above, and other methods may also be used. However, when using the external addition method, a large amount of water glass is attached to the surface of the paper product, and it is heated and dried. By doing so, it is possible to obtain a separator whose surface portion is strongly bonded by the added water glass and whose strength is improved. In this way, the mechanical strength and hardness of separators with stronger adhesion on the surface are significantly higher due to the strength and hardness of the surface, and the adhesion on the inside is weaker than on the surface.
1&1i when absorbing liquid! It has good IJ properties and excellent liquid retention and liquid absorption properties, which are extremely advantageous.

When a large amount of water glass is attached to the surface area in this way, the amount of water glass attached to the surface area from the surface of the paper product to approximately A of the total thickness is equivalent to the weight of the glass fibers in that area in terms of solid content. It is preferable that the amount is 5% by weight or more.

In addition, when making glass fibers, a dispersant may be used when dispersing the fibers in water, and a dialkyl sulfosuccinate may be added to a wet-processed fiber paper product, for example, a fiber paper product on a papermaking net. Spray the
By adding 0.005 to 10% by weight of dialkyl sulfosuccinate to the glass fiber, the liquid retention property of the separator can be improved due to the hydrophilicity of dialkyl sulfosuccinate. The dialkyl sulfosuccinate may be mixed into the dispersion water in the paper-making tank instead of being sprayed as described above. The thickness of the separator itself of the present invention varies depending on the storage battery used, but is generally 0.5 mm thick. It is preferable that it is 3-3 mm.

The separator for a storage battery of the present invention thus obtained preferably has a tensile strength of 400 g, 715 mm width x 1 mm thickness or more, a buckling strength of 30 g, 710 mm width x 1 mm thickness or more, and a liquid absorption rate of 80 mm 75 minutes or more.

[Function] The separator for storage batteries of the present invention is made of substantially only glass components, mainly glass fibers, and does not contain binders or binders, so it has extremely excellent liquid absorption and liquid retention properties. .

In addition, organic fibers and other organic adhesives that are normally used to improve the strength of separators may weaken the acid resistance of the separator, whereas separators made of glass components as in the present invention It has extremely excellent acid resistance.

In the present invention, the glass fibers constituting the separator are bonded to each other by water glass derived from a wood-glass adhesive, so that the strength and hardness of the separator are significantly improved.

〔Example〕

Examples and comparative examples will be described below.

Example 1 Glass fiber fi75gL with an average diameter of 0.8 μm and an average length of 10 mm whose composition is C in Table i1 and glass fiber with an average diameter of 4 pm and an average length of 15 mm @25ffl whose composition is C in Table 1 % in water, stirred and dispersed using a water jet disperser, and further added sulfuric acid to adjust the pH of the water to 2.
．． 7 and held for about 10 minutes. Next, papermaking is carried out, and a water glass adhesive (manufactured by Central Glass ■, trade name 5ilpap700) is added to the obtained papersheet by an external addition method in a solid content based on the weight of glass fiber #I. After adhering 5% by weight in terms of conversion, it was heated and dried at 150° C. to produce a matte separator for storage batteries.

Table 2 shows the results of measurements of the separator's loss on ignition, liquid absorption rate, tensile strength, buckling strength, maximum pore diameter, and liquid retention under pressure.

Comparative example 1 Except that I didn't use water glass adhesive.

A separator was manufactured in the same manner as in Example 1, and its shelf life was measured.

The results are shown in Table 2.

Table 2 From Table 2, the following is clear.

That is, the separator made of glass fibers of the present invention and bonded with water glass to which fibers are added has excellent liquid absorption and liquid retention properties equivalent to those of conventional separators made of glass fibers. In addition to maintaining high properties in other properties as well, the tensile strength and buckling strength have been significantly improved. 1 The waterglass fiber adhesion of the present invention has a significantly superior effect. be done.

The methods for measuring various characteristic values in Examples and Comparative Examples are as follows.

■ Thickness (mm) Measure the sample while pressing it with a load of 20 kg/dW in the thickness direction. (JISC-2202) ■ Fabric weight (g/cm') This is the value obtained by dividing the sample weight by the sample area.

■ Density (g/Cm') Area of sample (weight 1W) l OcmX 10 cm (S)
When T is the thickness of the sample when a load of 20 kg is applied to the
Represented by in.

■ Loss on ignition (%) Heat the sample in air to 600°C until it becomes constant, and calculate the loss by dividing the weight of the sample by the original weight of the sample.

(2) Liquid absorption rate (mm 15 minutes) It is determined by holding the sample vertically, immersing its lower part in a dilute sulfuric acid solution with a specific gravity of 1.3, and measuring the rise in the liquid level by -L over time after 5 minutes.

(2) Tensile strength (g/15mm width) The value of the external force when pulling both ends of a 15mm wide sample and cutting it is divided by the thickness and is expressed as the value (g) of width 15mm and thickness Inm.

■ Buckling strength (g/10mm width) Prepare a sample with a width of 50mm and a length of 100mm, hold the upper 50mm of the length with a holder, hold it so that the lower 50mm protrudes, and weigh the lower tip of the sample. The sample is pressed against the scale by gently lowering the holder, and the load (g) at the time of buckling is determined. and width 10
mm, converted to value per 1 mm thickness and displayed.

■ Maximum pore diameter (tom) Immerse four test pieces in a methanol solution for at least 30 minutes, set the sample in the sample holder of a commercially available maximum pore diameter measuring device, and pour 10 to 5 cc of methanol from the top with a pipette. Flow air gently, read the air pressure when bubbles are generated from methanol, and use a formula to determine the maximum pore diameter.

■ Liquid retention under pressure (g/cc) Thickness at 20kg/drn' load is inm and dimensions are 10
A cm x 10 cm sample was soaked in water and 20k thick in the thickness direction.
The water content (g) in the sample when a weight of g is applied is determined, and this is expressed as the value divided by the volume (CC) of the sample.

[Effects of the Invention] As detailed above, the storage battery separator of the present invention is mainly composed of glass fibers, and the glass fibers are JaR-treated with a water glass adhesive added during the manufacturing process. , (2) Since it is mainly made of glass fiber, it has good liquid absorption and liquid retention properties, especially excellent liquid retention property under pressure. Also,
It also has excellent oxidation resistance.

■ Because the glass fibers are stably bonded by water glass, high strength and hardness can be obtained.

It has excellent effects such as

Therefore, according to the separator of the present invention, a high-performance storage battery can be manufactured with excellent workability, and its industrial utility is extremely high.

Claims (6)

[Claims] (1) A separator for a storage battery, which is mainly composed of glass fibers and is characterized in that the glass fibers are bonded together with a water glass adhesive. (2) Mainly glass fibers with an average diameter of 2 μm or less, 0-35% by weight of glass fibers with an average diameter of 10-30 μm, and 0-3% by weight of glass fibers with an average diameter of more than 2 μm and less than 10 μm.
The separator for a storage battery according to claim 1, comprising 0% by weight. (3) The amount of water glass adhesive relative to the weight of glass fiber,
Claim 1: 1 to 10% by weight in terms of solid content
The separator for a storage battery according to item 1 or 2. (4) Any one of claims 1 to 3, wherein the tensile strength is 400 g/15 mm width x 1 mm thickness or more.
A separator for storage batteries as described in . (5) The separator for a storage battery according to any one of claims 1 to 4, which has a buckling strength of 30 g/10 mm radius x 1 mm thickness or more. (6) The separator for a storage battery according to any one of claims 1 to 5, which has a liquid absorption rate of 80 mm/5 minutes or more.