JP2932745B2 - Glass mat for storage battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass mat for a storage battery, and more particularly, to a storage battery disposed between a separator and an anode plate in a liquid battery such as a lead storage battery for the purpose of preventing the anode active material from falling off. Related to glass mats.

[0002]

2. Description of the Related Art Conventionally, in a liquid battery such as a lead storage battery, a technique of arranging a glass mat between a separator and an anode plate has been adopted for the purpose of preventing the anode active material from falling off. It has greatly contributed to the improvement. Heretofore, as the glass mat, a mat formed by bonding a glass fiber having an average diameter of 19 μm with an acrylic resin by a dry method has been used. That is, an acrylic resin is sprayed on the spun glass fiber and wound on a drum that reciprocates in the axial direction to form a roving in which the winding angle of the glass fiber is crossed. A mat-like material cut from the roving is spread. A felt mat manufactured by widening the crossing angle of glass fibers is used.

[0003] Glass mats made by such a dry method are:
Since the glass fiber is not cut short, it has good slipperiness, good stacker workability after uniting with the separator and cutting the small plate, and the average fiber diameter is as large as 19 μm, so the electric resistance is small and the battery performance is kept high. It has advantages such as being able to.

[0004] However, the conventional glass mats described above have a drawback that the gap between the electrode plates is likely to be uneven at the time of battery assembly because the thickness of the glass mat varies greatly and the thickness is uneven. That is, when manufacturing a glass mat by a dry method,
Since the felt obtained by spreading has uneven thickness, a glass mat having a uniform thickness cannot be obtained.

In the prior art, a plurality of the felts are used one on top of another to make the thickness uniform, but a sufficient effect has not been obtained.

[0006] To solve such problems,
The present inventors have found that 50 to 95% by weight of alkali-containing glass fibers having an average diameter of 13 to 15 μm and an average diameter of 17 to 21 μm
Consisting of 5 to 50% by weight of an alkali-containing glass fiber of
An acrylic resin binder having a glass transition point of 30 to 80 ° C. is added to a glass fiber mat manufactured by a wet papermaking method,
A glass mat for a storage battery having 15 to 25% by weight based on the weight of the glass fiber mat was found, and a patent application was previously filed (Japanese Patent Application No. 1-174950, hereinafter referred to as "first application"). According to the glass mat for storage battery, the storage battery has good slipperiness, excellent workability of stacker after being combined with the separator and cutting the small plate, low electric resistance, little variation in thickness, and uniform thickness. A glass mat is provided.

[0007]

The glass mat for a storage battery of the prior application is cut into small plates by laminating with a separator, punched out by a stacker in a battery assembling process, and superimposed on an electrode plate to form an electrode plate group. A hard and rigid glass mat for storage batteries to make.

On the other hand, in recent years, battery assembling methods have been diversified. For example, a battery assembling method in which a separator and a glass mat are bonded in a strip shape and interposed in a zigzag manner between a plurality of electrode plates has also been implemented. It was started. However, when such a battery assembling method is employed, the glass mat for a storage battery of the prior application described above is hard and has too high a rigidity, so that a problem occurs in that the glass mat is broken at a folding position of the self-folding.

The present invention solves the problems caused by its rigidity while maintaining the features of the above-mentioned prior application, and has a sufficiently flexible glass mat for a storage battery which does not break even when bent in a battery assembly process. The purpose is to provide.

[0010]

The glass mat for a storage battery of the present invention has an average diameter of 16 to 21 μm and an average length of 30 to 1 μm.
An acrylic resin binder having a glass transition point of 0 to −40 ° C. is added to a glass fiber mat manufactured by a wet papermaking method, which is composed of 00 mm alkali-containing glass fiber, and 8 to 15 weight based on the weight of the glass fiber mat. %.

Hereinafter, the present invention will be described in detail. The glass mat for a storage battery of the present invention is a glass fiber mat manufactured by a wet papermaking method, and its constituent glass fibers are alkali-containing glass fibers having an average diameter of 16 to 21 μm and an average length of 30 to 100 mm.

By the way, in a glass mat for a storage battery by a wet papermaking method, the following may be considered. That is, when the average diameter of the constituent glass fibers is large, for example, when the glass fibers have an average diameter of 19 μm and are 100% by weight, the obtained glass mat becomes poor in slip and good handling workability cannot be obtained. . That is, in order to form a glass mat by a wet papermaking method, it is necessary to use glass fibers cut to a length of 6 to 30 mm, but when forming glass fibers of such a length, the diameter of the glass fibers is large. As a result, the glass mat obtained due to the rough glass fiber end face has poor slip. Therefore, from the viewpoint of preventing the slip of the glass mat from decreasing due to the end face of the glass fiber, the diameter of the constituent glass fiber is preferably as small as possible, for example, 100% by weight of the glass fiber having an average diameter of 14 μm.
The glass mat composed of the above has good sliding characteristics.

However, when the electric resistance of the glass mat is considered, when the average diameter of the constituent glass fibers is small,
For example, it is not preferable that the mat is made of 100% by weight of glass fiber having an average diameter of 14 μm, because the mat becomes too clogged and the electric resistance becomes large.

Accordingly, in order to obtain a glass mat having good slippage and low electric resistance, the glass mat for the storage battery of the prior application has an average diameter of 13 to 15 μm.
m to 50 to 95% by weight of alkali-containing glass fibers and 5 to 50% by weight of alkali-containing glass fibers having an average diameter of 17 to 21 μm.

However, as a result of research, the present inventors have found that by using an appropriate dispersant, the average length can be reduced to 30 to 30 μm.
It has been found that glass fibers of 100 mm can be dispersed well and that it is not necessary to use glass fibers cut to 6 to 30 mm. And average length 30-1
By using a relatively long glass fiber of 00 mm, the glass fiber end surface that makes the mat slippery described above decreases, and the mat slides better.
It is no longer necessary to use a glass fiber having such a small diameter, and it is possible to use glass fiber having an average fiber diameter of 16 to 21 μm and 100%. Therefore, in the present invention, the average fiber diameter is 16 to 21 μm, and the average length is 30 to
100 mm glass fiber is used.

In the present invention, the glass transition temperature (T
g) 8 to 15% by weight of an acrylic resin binder having a temperature of 0 to -40 ° C based on the weight of the glass fiber mat.

Here, if the Tg of the acrylic resin binder used is lower than -40 ° C., the slipperiness of the obtained glass mat is deteriorated, the binder is spread, and the resistance value of the obtained glass mat is large. Becomes Conversely, T
When the g exceeds 0 ° C., the obtained glass mat becomes hard and brittle and easily breaks.

As the acrylic resin binder suitable for the present invention, an acrylic ester copolymer containing methyl methacrylate and acrylic acid as main components and having a Tg of 0 to -40 ° C. can be mentioned.

When the amount of the acrylic resin binder adhered is less than 8% by weight based on the weight of the glass fiber mat, the tensile strength of the glass mat is weak, and it is difficult to obtain the necessary strength at the time of processing. If it exceeds, the cracks are liable to occur and the electrical resistance increases, which is not preferable in any case.

In the present invention, among the alkali-containing glass fibers, those having good acid resistance are preferably used because they are used for storage batteries. The degree of the acid resistance is determined in the state of glass fiber having an average fiber diameter of 1 μm or less according to JISC-JIS.
Desirably, the weight loss when measured according to 2202 is 2% or less. Further, the composition of such glass fibers is 60 to 75% SiO ₂ and 8 to 20% by weight.
R ₂ O (alkali metal oxides such as Na ₂ O and K ₂ O) (wherein SiO ₂ + R ₂ O is 75%).
90%), Other example CaO, MgO, B ₂ O
₃ or one or two of Al ₂ O ₃ , ZnO, Fe ₂ O _3, etc.
And those containing more than one species. An example of a preferred alkali-containing silicate glass is shown in Table 1 below.

[0021]

[Table 1]

In order to manufacture the glass mat for a storage battery of the present invention, for example, the following method is advantageous. That is, it was manufactured by a long fiber manufacturing method in which continuously melted glass was pulled out from a nozzle and wound around a drum,
A continuous filament is prepared and cut into a predetermined length by a cutter. Alternatively, the glass fiber may be cut into a predetermined length by an appropriate cutting means while the glass fiber is supplied to the paper machine net.

The cut glass fiber having a predetermined length and a predetermined fiber diameter is formed into a net-like paper. At this time, the viscosity of water in the disintegrator and / or the viscosity of the paper in the paper-making tank are determined using a viscous material. Is preferably about 3 to 15 centipoise. The glass fiber is dispersed by performing wet papermaking with such a viscosity.

In the present invention, a predetermined amount of an acrylic resin binder is applied to such a glass fiber papermaking sheet by applying a method such as spraying, impregnation or a curtain coating method to form a battery glass mat.
The storage battery glass mat of the present invention obtained by such a wet papermaking method is a glass mat having excellent thickness uniformity whose thickness variation is within a standard value ± 10%.

[0025]

According to the wet papermaking method, since a stable sheet can be obtained continuously, the battery glass mat of the present invention has a uniform thickness with little variation in thickness. The average length of the glass fiber used in the present invention is 30.
Since the thickness is ｍｍ100 mm, a glass mat for a storage battery is provided which has good slipperiness, excellent bonding properties with a separator, and excellent workability. Moreover, the average diameter of the glass fibers is 16 to 2
Because of the relatively large thickness of 1 μm, a glass mat with low electric resistance is provided at low cost. In addition, since the binder has a Tg of 0 to -40 ° C, the binder is flexible, has excellent crack resistance when bent, and has a binder adhesion of 8 to 40 ° C.
Since the content is 15% by weight, the electric resistance can be kept low.

[0026]

The present invention will be described more specifically with reference to the following examples. Example 1 In the glass fiber configuration shown in Table 2, an acrylic resin binder having a Tg shown in Table 2 was adhered by a wet method at an adhesion amount shown in Table 2 (ratio to the glass fiber weight).
A glass mat having a thickness of 0.6 mm was manufactured. For each glass mat, the slipperiness, crack resistance, tensile strength, and electric resistance were examined by the following methods, and the results are shown in Table 2 together with the results of determination as glass mats for storage batteries.

Slippery (g) Using two samples of 100 mm × 100 mm, one sample is laid on a measuring table, and a 5 kg-weight of 10 mm in width is placed on the edge of the sample. Place the other sample on it (2
The overlap area of the samples is 90 mm × 100 mm), and a bake plate (100 mm × 100 mm) is laid thereon and a load is applied thereon. The sample sandwiched between is pulled through a push-pull gauge, and the load on the push-pull gauge when the sample starts to move is read.

Cracking resistance The sample that was broken when bent was evaluated as x, and the sample that did not crack was evaluated as ○. Tensile strength (kg / 15mm width) The external force value (g) when the both ends of a sample with a width of 15 mm are pulled and cut is determined, and divided by the thickness (mm) to obtain a width of 15 m.
It is indicated by a value per m and a thickness of 1 mm.

Electric resistance (Ω · dm ² / sheet) Measured according to JISC2313. As a result, the ones outside the scope of the present invention (Nos. 1, 3, 6, 7, 9) lacked the required characteristics as glass mats for storage batteries. 2,4,5,8 had good properties.

[0030]

[Table 2]

[0031]

As described in detail above, the glass mat for a storage battery of the present invention has good slipperiness. With moderate flexibility and high strength. Excellent crack resistance.
, More excellent handling and workability when assembling the storage battery. Electric resistance is small. Small variations in thickness. , A higher performance storage battery can be manufactured. Since glass fibers having a relatively large diameter are used, the cost can be reduced. It is extremely industrially useful as a glass mat for a storage battery.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-40365 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01M 2/16

Claims (1)

(57) [Claims] 1. An average diameter of 16 to 21 μm and an average length of 30
An acrylic resin binder having a glass transition point of 0 to -40 ° C is added to a glass fiber mat made of a wet papermaking method, which is made of an alkali-containing glass fiber having a glass transition temperature of 8 to 15 mm. A glass mat for a storage battery, wherein the glass mat is attached by weight%.