WO1998022988A1

WO1998022988A1 - Separator for lead-acid battery and method for manufacturing the same

Info

Publication number: WO1998022988A1
Application number: PCT/JP1997/004255
Authority: WO
Inventors: Toshikazu Senoo; Masaki Shoji; Kunio Tabata; Kenzo Sakata
Original assignee: Mitsui Chemicals, Inc.
Priority date: 1996-11-21
Filing date: 1997-11-21
Publication date: 1998-05-28

Abstract

A separator for lead-acid battery is constituted of a synthetic pulp in which texture of constituent fibers is complicated, and a laminated sheet (III) forming a coated layer (II) of an inorganic powder and an acid-proof polymer at least on one surface of a porous substrate sheet (I), comprising an acid-proof inorganic powder and an acid-proof inorganic fiber, and manufactured by a wet papermaking process. The separator can be formed of a sheet-like or a bag-like laminated sheet, and it is possible to form projecting sections on at least one surface of the sheet (III) or no projecting section on the surfaces of the sheet (III). In a method for manufacturing the separator, the laminated sheet (III) is manufactured in such a way that the porous substrate sheet (I) is prepared by a wet papermaking process by scattering the synthetic pulp in which texture of constituent fibers is complicated and acid-proof inorganic powder and/or acid-proof inorganic fibers in a medium, and the coated layer (II) is formed by coating a pasty mixed solution prepared by adding water to the inorganic powder and acid-proof polymer to at least one surface of the sheet (I) and drying the solution so that the solid content percentage amounts to 10-70 wt.%. The above-mentioned projecting sections can be formed through an embossing process or rib forming process. When this invention is used, a separator for lead-acid battery having a lower electrical resistance and an excellent acid-proof can be obtained, and a sheet-like or bag-like separator having projecting sections on at least one surface of the laminated sheet (III) or having no projecting section on the surfaces of the sheet (III) can be obtained.

Description

* H »Separator for lead-acid battery and its manufacturing method

The present invention relates to a separator for a lead-acid battery and a method for producing the same, and more particularly, to a separator for a lead-acid battery having low electric resistance and excellent oxidation resistance, and particularly suitable for an automobile and a method for producing the same. . Background art

Lead-acid battery separators for automobiles are required to have low electric resistance and excellent oxidation resistance. In order to meet these requirements, as a separation, a slurry obtained by mixing a synthetic resin powder or a silica-based inorganic powder with it and suspending it in water is used as a porous material such as a nonwoven fabric. Separator impregnated in a hydrophilic base sheet (JP-A-57-95071, JP-A-6-237675) and lipophilic polymer fibers Abstract Separator impregnated with a water-soluble oil emulsion (Japanese Patent Publication No. 416,462), or synthetic resin emulsion made by imparting viscous properties to a sheet mainly composed of glass fiber. Is known (Japanese Patent Application Laid-Open No. Sho 60-130550).

In a separator in which a coating layer of a mixture of an inorganic powder and a synthetic resin is formed on a porous substrate sheet, an increase in electric resistance due to the formation of the coating layer is inevitable. No. 5 7-950 7 1 ゃ Non-woven fabric or woven fabric disclosed in Japanese Patent Application Laid-Open No. 6-2 36572 And the separators one data using to, in order to improve the oxidation resistance, the basis weight of the coating layer comprising a mixture of an inorganic powder and a synthetic resin such as 5 0~ 1 5 0 g / m 2 The electrical resistance becomes too large because it must be increased.

Separate paper sheets impregnated with synthetic resin emulsions, disclosed in Japanese Patent Publication No. 4-6146 and Japanese Patent Application Laid-Open No. 60-15050, are also disclosed. Similarly, an increase in electrical resistance due to the impregnation of the synthetic resin emulsion is inevitable, but a large amount of synthetic resin emulsion is required in order to significantly improve the oxidation resistance. Too big.

Therefore, these separations have not sufficiently satisfied the above requirements as separations for lead-acid batteries.

Further, as a separator having a rib for the purpose of satisfying the above requirements as a lead storage battery separator, a bag-shaped separator is used, and the separator material is bent at predetermined intervals. Separate unit having a plurality of line-ribs in which a chevron-shaped convex portion is formed inside the bag in a vertical direction (Japanese Patent Application Laid-Open No. 3-127448). I-like seno ,. A separator having a plurality of so-called pipe-shaped ribs in which pipe-shaped protrusions made of a thermoplastic resin are formed at predetermined intervals on one side of a base material of the separator (Japanese Patent Laid-Open No. 63-51010) 4 No. 6) is known.

One of the main roles of the ribs in Separete is to secure the necessary space between the electrodes in the battery to maintain the required amount of electrolyte. However, in the case of the bag-shaped separator having a line rib disclosed in the above-mentioned Japanese Patent Application Laid-Open Publication No. 3-127428, the electric power is insufficient due to insufficient strength. The electrode group pressure in the pond causes deformation such as crushing of the line rib, and the space required for holding the electrolyte is insufficient.

As an improved product, a bag-shaped separator in which a rib formed by embedding a line rib of the above shape and a synthetic resin in the vertical direction is formed inside the bag has been proposed (JP-A-3-13888). No. 55). However, although this bag-shaped separator has been improved in terms of securing the space required to hold the electrolyte, the separator substrate itself has not been improved, and it is used as a separator for lead-acid batteries. Cannot meet all the requirements of oxidation resistance.

In addition, even in the separators having pipe-like ribs proposed in Japanese Patent Application Laid-Open No. 63-51046, the ribs are easily deformed due to the space inside the ribs, and Insufficient space for holding liquid. Further, this type of separator has not been improved in the separator substrate itself, as in the separator proposed in Japanese Patent Application Laid-Open No. HEI 3-138855. It is not possible to fully satisfy the requirements of a separator with excellent oxidation resistance.

The present inventors have studied diligently to solve the above-mentioned problems, obtain a separation for a lead storage battery having low electric resistance and excellent oxidation resistance, and have been manufactured by a wet papermaking method and have a large number of constituent fibers. A coating layer containing an inorganic powder and an acid-resistant polymer on at least one side of a porous substrate sheet made of a synthetic pulp in a branched state and acid-resistant inorganic powder and / or acid-resistant inorganic fiber. And a separator made of a laminated sheet having the above-described coating layer formed on the surface opposite to the convex portion formed on one surface of the porous substrate sheet. Has low electrical resistance As a result, they found that they had excellent oxidation resistance and the like, and completed the present invention.

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and is a sheet-shaped or bag-shaped separator for a lead storage battery having low electric resistance and excellent oxidation resistance, and its production. It aims to provide a method. Disclosure of the invention

The lead-acid battery separator according to the present invention comprises:

A porous base material made of a synthetic pulp (a) in which the constituent fibers are in a multi-branched state and an acid-resistant inorganic powder (b) and / or an acid-resistant inorganic fiber (c), which is produced by a wet papermaking method. It is characterized by comprising a laminated sheet (m) in which a coating layer (Π) containing an inorganic powder (d) and an acid-resistant polymer (e) is formed on at least one surface of the sheet (I). ing.

In the separator for a lead storage battery according to the present invention, a convex portion may be provided on one or both surfaces of the laminated sheet (ΠΙ). For example, on the surface of the porous base sheet (I) layer of the laminated sheet (m), projections may be formed continuously or discontinuously on substantially the same line, A plurality of protrusions formed continuously or discontinuously on the same straight line may be formed at predetermined intervals in the width direction.

Such a convex portion may be formed in a rib shape by hot-melt type resin, or may be formed by embossing the porous base sheet (I). As an example of such a separator for a lead storage battery, a porous base sheet (I) is embossed. The convex portion is formed on one surface of the porous substrate sheet (I) on the surface opposite to the surface on which the convex portion is formed. Separation evening where (セ) is formed.

Further, the laminated sheet (m) may be formed in a bag shape. As the porous base sheet (I),

Synthetic pulp (a) 5 to 70% by weight,

Acid resistant inorganic powder (b) and Z or acid resistant inorganic fiber (c) 5 to 60% by weight,

5 to 50% by weight of synthetic fiber (f) and / or composite adhesive fiber (g)

A sheet consisting of

Synthetic pulp (a) 5 to 70% by weight,

Acid resistant inorganic powder (b) and / or acid resistant inorganic fiber (c) 5 to 60% by weight,

5 to 50% by weight of the synthetic fiber (f) and / or the composite adhesive fiber (g);

A binder (h) having a melting point lower than the melting point or the decomposition temperature of the synthetic pulp (a), or a binder (h) exhibiting an adhesive force at the above-mentioned temperature of 0.5 to 10% by weight;

A sheet consisting of is preferably used.

It is particularly preferable that the dry basis weight of the coating layer (Π) is in the range of 5 to 50 g / m ² .

The coating layer (Π) has an inorganic powder (d) of 30 to 90% by weight <%, The acidic polymer (e) preferably comprises 10 to 70% by weight, and the inorganic powder (d) constituting the coating layer (Π) has an average particle size of 10 βm or less. Inorganic powder having a specific surface area of 100 to 250 m ² / g (i) 100 to 90% by weight, an average particle diameter of 1 to 30 m, and a specific surface area of 0 It is preferably a mixture with inorganic powder of 1 to 50 m ² / g (ii) 90 to 10% by weight.

The average pore size of the laminated sheet (ΙΠ) is preferably in the range of 0.1 to 10 ^ m.

The method for producing a separation battery for a lead storage battery according to the present invention includes:

The synthetic pulp (a) in which the constituent fibers are in a multi-branched state, the acid-resistant inorganic powder (b) and Z or the acid-resistant inorganic fiber (c) are dispersed in a medium, and the porous base material is formed by a wet papermaking method. Prepare sheet (I),

Next, a paste-like mixed solution prepared by adding water so that the solid content concentration of the inorganic powder (d) and the acid-resistant polymer (e) is 10 to 70% by weight is added to the porous substrate sheet. It is characterized in that it is applied on at least one side of the sheet (I) and dried to form a coating layer (Π) to form a laminated sheet (m).

The porous substrate sheet (I) is

Synthetic pulp (a) 5 ~ 70 weight ° '' 0,

5 to 50% by weight of synthetic fiber (f) and Z or composite type adhesive fiber (g)

The force formed from, or Synthetic pulp (a) 5 to 70% by weight,

It is preferably formed from

The porous base sheet (I) preferably has a porosity of 50% or more and an average pore diameter of 0.5 to 20 m.

The mixing ratio [(d) / (e)] of the inorganic powder (d) and the acid-resistant polymer (e) constituting the solid content in the paste-like mixture is 30 Z70 to 90. / 10 is preferred.

It is preferable to apply the paste-like mixed solution to at least one surface of the porous base sheet (I) using a coater.

The laminated sheet (Π) having the convex portions formed on the surface is formed, for example, by forming the coating layer (Π) on at least one surface of the porous base sheet (I) and forming a laminated sheet (m). After the production, a linear rib can be bonded and formed on one or both sides of the laminated sheet (m) using a hot melt type resin.

In the present invention, the porous substrate sheet is produced by a wet papermaking method.

After the production of (I) or the production of the laminated sheet (ΙΠ), the bonding of the composite adhesive fiber (g) constituting the porous base sheet (I) It is preferable to perform the heat treatment at a temperature not lower than the temperature and not higher than the melting point of the synthetic pulp (a) or at a temperature at which the binder (h) exhibits an adhesive force.

Further, the laminated sheet (m) having the convex portions formed on the surface is manufactured by manufacturing the porous substrate sheet (I) by a wet papermaking method and then using an embossing roll to form the porous substrate sheet (I). On the sheet (I), an embossing process for forming a substantially linear convex portion continuously or discontinuously is performed.

Next, the solid content of the inorganic powder (d) and the acid-resistant polymer (e) is 10 to 70% on the surface of the porous substrate sheet (I) opposite to the surface on which the projections are formed. It can be obtained by applying a paste-like mixed solution prepared by adding water to a concentration of water and drying it to form a coating layer (Π).

In this method, after the porous substrate sheet (I) is produced by a wet papermaking method, the composite substrate is made of a composite adhesive fiber (g) constituting the porous substrate sheet (I) at an adhesion temperature or higher and synthesized. The heat treatment is performed at a temperature lower than the melting point of the pulp (a) or at a temperature at which the binder (h) exhibits an adhesive force, and then the embossed roll is used to form a porous substrate sheet (I). , Embossing to form almost linear projections,

Next, the solid content concentration of the inorganic powder (d) and the acid-resistant polymer (e) is 10 to 70 on the surface of the porous substrate sheet (I) opposite to the surface on which the projections are formed. It is preferable to apply a paste-like mixed solution prepared by adding water so as to have a weight%, and then dry to form a coating layer (Π) to form a laminated sheet (ΠΙ).

Further, the laminated sheet (m) having the convex portions formed on the surface is the laminated sheet (m). — After manufacturing (g), it can also be obtained by embossing using an embossing roll to form a substantially linear projection continuously or discontinuously.

In the method for manufacturing a separator for a lead storage battery according to the present invention, the laminated sheets (πι) obtained by the above-described manufacturing method are overlapped, and one end thereof is sealed to form one opening. It can be a bag. A brief description of the screen

FIG. 1 is a schematic view showing an example of a coating apparatus used for forming a coating layer (π) on the surface of a porous substrate sheet (I) in the present invention.

FIG. 2 is a cross-sectional view showing an example of a laminated sheet (m) in which a rib is formed on the surface of a porous substrate sheet (I).

Also, FIGS. 3, 4 and 5 show that the coating layer (Π) is formed on one side of the porous substrate sheet (I) on which the protrusions are formed by embossing, on the side opposite to the protrusions. It is sectional drawing which shows the example of a laminated sheet. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a separation battery for a lead storage battery according to the present invention and a method for manufacturing the same will be specifically described.

The lead storage battery separator according to the present invention comprises a laminated sheet (m) having a coating layer (π) formed on one or both sides of a porous substrate sheet (I).

Porous substrate sheet (I), The porous substrate sheet (I) is manufactured by a wet paper-making method, and is composed of a synthetic pulp (a), an acid-resistant inorganic powder (b) and Z or acid-resistant inorganic fiber (c). And, if necessary, a synthetic fiber (f) and / or a composite adhesive fiber (g), and a binder having a melting point lower than the melting point of the synthetic pulp (a) or a decomposition temperature (a). h).

Synthetic pulp (a)

In the synthetic pulp (a) used in the present invention, it is preferable that fibers constituting the pulp are in a multi-branched state and have acid resistance. As such a synthetic pulp (a), specifically,

Ethylene and other oligomers such as polyethylene homopolymers such as polyethylene and polypropylene, or ethylene-propylene copolymers, ethylene-tributene copolymers, and ethylene 4-methyl-1-pentene copolymers In addition to polyolefin-based synthetic pulp containing polyolefin as a main component consisting of a copolymer with styrene, polystyrene, polymethylmethacrylate, polyacrylonitrile, vinyl chloride resin, vinylidene chloride Synthetic pulp mainly composed of polymers such as resin, nylon, polyester, and polyfluoroethylene can be used. Among them, polyolefin synthetic pulp is preferably used because it is excellent in acid resistance and inexpensive. Among polyolefins, ethylene-based polymers and propylene-based polymers are preferably used from the viewpoint of acid resistance.

Here, “acid resistance” means acid resistance to sulfuric acid aqueous solution, which is an electrolyte solution for lead-acid batteries. Synthetic pulp that does not undergo shape change or chemical change even when immersed in sulfuric acid aqueous solution, specifically For the pulp, a synthetic pulp having an acid resistance value of 0.6% or less specified in JISC 222 is preferable. In addition, when heat sealing is performed at the time of producing a bag-shaped separator, synthetic pulp (a) exhibits a large adhesive strength. (MFR; ASTM D 1238, 190 ° C, 2.16 kg load) is 10 g / 10 min or less, preferably 0.1 to 5 g Z 10 min. For propylene-based polymer, The weight (MFR; ASTM D 1238, 230; C, 2.16 kg load) should be 30 g / 10 minutes or less, and preferably 0.1 to 20 g / 10 minutes.

In the synthetic pulp (a), the constituent fibers have many branches, and the average fiber length is preferably 0.1 to 10 mm. When synthetic pulp (a) having an average fiber length within the above range is used, the entanglement between the fibers is sufficient, so that the sheet can be easily formed and a uniform porous substrate sheet ( I) can be easily obtained.

Furthermore, the freeness of synthetic pulp (a) (measurement method: JISP 8121) is 1.0 to 20.0 seconds / g, especially 2.0 to 10.0 seconds / g. I prefer that there be. When a synthetic pulp having a freeness within the above range is used, a porous substrate sheet (I) having sufficient strength, having appropriate voids, and having good liquid permeability is used. Can be obtained.

The synthetic pulp (a) used in the present invention is known per se. For example, as described in detail in Encyclopedia of Chemical Technology 3rd ed. Is manufactured.

Here, the term "wet papermaking" refers to a method of papermaking using water or various solvents, and is not particularly limited. Preferred examples of the method include a solution flush or an emulsion flash. After performing a flash, A method of performing a beating process and the like are included.

The synthetic pulp (a) used in the present invention is a pulp used for so-called paper or sheet production. Since the constituent fibers have a multi-branched structure, the fibers are entangled with each other when formed into a sheet. However, the void forms a complicated passage. On the other hand, webs composed of single fibers such as nonwoven fabrics have a pore structure that is essentially different from synthetic pulp (a), and nonwoven fabrics have relatively large through-holes and a straight structure. Therefore, when a coating liquid containing the inorganic powder (d) and the acid-resistant polymer (e) is applied, a large amount of the coating layer (Π) formed enters between the fibers and the laminated sheet

The effect of the coating layer (Π) for controlling the pore diameter of (ΠΙ) is impaired, and if the coating layer (Π) is made thicker to produce the effect as the coating layer, the effect will be lost. There is a problem that the resistance increases, and the object of the present invention cannot be achieved.

Synthetic pulp (a) is synthetic pulp (a), acid-resistant inorganic powder (b), acid-resistant inorganic fiber (c), synthetic fiber (f), composite adhesive fiber (g) and binder (h) It is preferably used in an amount of 5 to 70% by weight, particularly preferably 10 to 50% by weight, based on the total amount of 100% by weight.

Acid-resistant inorganic powder (b)

Specific examples of the acid-resistant inorganic powder (b) used in the present invention include synthetic silica, silica earth, and silicon. Powders such as monolite, alumina, zeolite and the like can be mentioned. Of these, synthetic silica is preferably used.

These acid-resistant inorganic powders (b) can be used alone. Alternatively, two or more kinds can be used in combination.

Here, the “acid resistance” of the acid-resistant inorganic powder (b) has the same meaning as described above, and the acid-resistant inorganic powder (b) changes its shape and chemical even when immersed in an aqueous sulfuric acid solution. It is an inorganic powder that does not cause a specific change, specifically, an inorganic powder having an acid resistance value of 0.6% or less specified in JISC 222.

Acid-resistant inorganic powder (b) includes synthetic pulp (a), acid-resistant inorganic powder (b), acid-resistant inorganic fiber (c), synthetic fiber (f), composite adhesive fiber (g) and It is preferably used in an amount of 5 to 60% by weight, particularly preferably 10 to 50% by weight, based on 100% by weight of the binder (h).

Acid-resistant inorganic fiber (c)

Specific examples of the acid-resistant inorganic fiber (c) used in the present invention include glass fiber, silica fiber, and alumina silicate fiber. Of these, glass fibers are preferably used.

These acid-resistant inorganic fibers (ji) can be used alone or in combination of two or more.

Here, the “acid resistance” of the acid-resistant inorganic fiber (c) has the same meaning as described above, and the acid-resistant inorganic fiber (c) has a shape change and a chemical change even when immersed in a sulfuric acid aqueous solution. Inorganic fibers that do not cause water, specifically, inorganic fibers having an acid resistance value of 0.6% or less specified in JISC 222.

Acid-resistant inorganic fiber (c) is synthetic pulp (a), acid-resistant inorganic powder (b), acid-resistant inorganic fiber (c), synthetic fiber (f), composite adhesive fiber It is used in an amount of preferably 5 to 60% by weight, particularly preferably 10 to 50% by weight, based on 100% by weight of the total amount of the fiber (g) and the binder (h).

Synthetic fiber (f)

Specific examples of the synthetic fiber (f) used as required in the present invention include polyamide (nylon), polyethylene terephthalate (PET), and polypropylene (PP). And a fiber made of a synthetic resin such as polyethylene (PE).

These synthetic fibers (f) can be used alone or in combination of two or more.

The synthetic fiber (f) used in the present invention preferably has a melting point higher than the melting point of the binder (h) or the bonding temperature of the composite adhesive fiber (g). It is preferable to have excellent acid resistance as described above.

Synthetic fiber (f) is used as a reinforcing component to increase the rigidity and strength of the base sheet. Synthetic pulp (a), acid-resistant inorganic powder (b), acid-resistant inorganic fiber (C), synthetic fiber (f), conjugate adhesive fiber (g) and binder (h), based on a total amount of 100% by weight, preferably 5 to 50% by weight, particularly preferably Is used in an amount of 10 to 40% by weight.

Composite adhesive fiber (g)

As the composite adhesive fiber (g) used as required in the present invention, an adhesive fiber combining a high melting point component and a low melting point component, for example, polypropylene (PP) / polyethylene (PE) , Polyethylene Adhesive fibers having a side-by-side type / core-sheath type structure by a combination of terephthalate (PET) / low-melting point PET and the like are listed. In this composite fiber, the low-melting-point component is disposed outside.

These composite adhesive fibers (g) can be used alone or in combination of two or more.

The bonding temperature of the composite adhesive fiber (g) is 10 ° C higher than the lowest of the melting point or decomposition temperature of synthetic pulp (a) and the melting point or decomposition temperature of synthetic fiber (f). It is desirable that it is lower than this.

The composite adhesive fiber (g) is used as a reinforcing component to increase the rigidity and strength of the base sheet, similarly to the synthetic fiber (f), and the synthetic pulp (a) 100% by weight of acid-resistant inorganic powder (b), acid-resistant inorganic fiber (c), synthetic fiber (f), composite adhesive fiber (g) and binder-(h) It is preferably used in an amount of 5 to 50% by weight, particularly preferably 10 to 40% by weight.

When the composite adhesive fiber (g) is used, the effect as the binder (h) described later is also exerted at the same time, so that the binder (h) is not used. It is not necessary to use it, but in order to further increase the strength, it is preferable to use the binning (h) together.

Daichi (h)

The binder (h) used as necessary in the present invention is intended to bind pulp, fiber, and inorganic powder to give strength to the porous base sheet (I). In the present invention, a heat-bonding binder is used, which exhibits an adhesive force at a temperature lower than the melting point or decomposition temperature of the synthetic pulp (a). Examples of such a heat bonding type binder include polyethylene, polypropylene, and other polyolefins having a melting point lower than the melting point of synthetic pulp (a), polystyrene, polymethyl methacrylate, and polyacryl. Examples include rilonitrile, vinylidene chloride resin, nylon and polyester.

Also, the form of the binder (h) is, for example,

Various synthetic fibers having the same raw material as the synthetic pulp (a); as described above, the core has a melting point higher than the melting point of the synthetic pulp (a), and the sheath has the melting point of the synthetic pulp (a). A so-called core-sheath composite fiber having a lower melting point than the melting point;

Polyolefin resin powder, low melting polyester powder, vinyl chloride resin powder, epoxy resin powder, or emulsion thereof; natural or synthetic rubber latex; and

Examples include acrylic resin emulsions.

These binders (h) can be used alone or in combination of two or more.

The melting point of the binder (h) is the melting point or decomposition temperature of the synthetic pulp (a) or the melting point or decomposition temperature of the high melting point of the composite adhesive fiber (g) out of the melting point or decomposition temperature of the synthetic fiber (f). It is desirable that the temperature be lower than the lowest temperature by 10 ° C or more. When the binder (h) is an amorphous polymer such as rubber, the temperature at which the amorphous polymer softens and exhibits adhesiveness may be used as a guide for the heat treatment temperature.

Binder (h) is synthetic pulp (a), acid-resistant inorganic powder (b), acid-resistant inorganic fiber (c), synthetic fiber (f), composite adhesive fiber (g) And 100% by weight or less, preferably 0.5 to 10% by weight, particularly preferably 1 to 5% by weight, based on the total amount of 100% by weight of the binder (h). Used. Porous substrate sheet (I)

The porous substrate sheet (I) used in the present invention comprises synthetic pulp (a), acid-resistant inorganic powder (b) and Z or acid-resistant inorganic fiber (c), and if necessary, synthetic fiber. (F) and a warm-formed article formed from Z or the composite adhesive fiber (g) and a binder (h). Among them, synthetic pulp (a) 5 to 70% by weight, acid-resistant inorganic powder (b) and Z or acid-resistant inorganic fiber (c) 5 to 60 weight <¾, synthetic fiber (f) and or 5 to 50% by weight of the composite adhesive fiber (g) and 0 to 10% by weight of a binder (h) having a melting point lower than the melting point or decomposition temperature of the synthetic pulp (a). The porous base sheet (I) made of In particular, synthetic pulp (a) 10 to 50% by weight, acid-resistant inorganic powder (b) and Z or acid-resistant inorganic fiber (f) 10 to 50 weight ⁰ , synthetic fiber (f) and A porous base sheet (I) comprising 10 to 40% by weight of a composite adhesive fiber (g) and 0.5 to 10% by weight of a binder (h) is preferred. New

The porous substrate sheet (I) produced by the wet papermaking method using each of the above components has a porosity of 50% or more and an average pore diameter of 0.5 to 20 m. It is preferable that the maximum pore diameter is 200 m or less.

The porosity is determined by the apparent volume of the sample as V and the weight of the sample as the density of the material. When the volume obtained by dividing by degrees is VQ, this is the value obtained by the following equation.

Porosity (%) = {(V-V.) ZV} x l 0 0

The average pore size and the maximum pore size are as shown in “POROUS

MATERIALS, INC.), Based on ASTM F316-86.

If the average pore size of the porous base sheet (I) is smaller than 0.5 Zm, it becomes difficult to produce the sheet by a wet paper-making method, and furthermore, the electrical resistance of the obtained separator becomes high.

When the average pore size of the porous substrate sheet (I) is larger than 20 / m, the inorganic powder (d) and the acid-resistant material are attached to one or both surfaces of the porous substrate sheet (I). When the coating layer (（) containing the reactive polymer (e) is formed, it is difficult to control the laminated sheet (II) with a small pore size and uniformity.

Incidentally, if the maximum pore diameter of the porous base sheet (I) exceeds 200 m, it is not desirable because the active material dropped from the electrode may slip and cause a short. Preparation of porous substrate sheet (I)

The porous base sheet (I) may be, for example, the above-mentioned synthetic pulp (a) and at least one kind of acid-resistant inorganic powder (b) or acid-resistant inorganic fiber (c), if necessary. A mixture containing at least one of the synthetic fiber (f) or the composite adhesive fiber (g) and the binder (h) is dispersed in a medium such as water and wet-processed. Preparation Is done.

In this wet papermaking, a warmed sheet of the above mixture is papered on a net. This wet sheet may be dewatered only, or dewatered and lightly pressed. The dehydrated sheet is sent to a drying step, and is preferably dried with a hot air oven using a hot air oven or a drum type dryer.

In the present invention, it is preferable that the dried sheet is heat-treated following the drying step. This heat treatment is also preferably performed in a hot air oven or a drum type dryer. Drying and heat treatment may be performed simultaneously.

This heat treatment is performed at a temperature not lower than the bonding temperature of the composite adhesive fiber (g) and not higher than the melting point of the synthetic pulp (a), or not lower than the melting point of the binder (h) and not higher than the melting point of the synthetic pulp (a). At a temperature of In particular, at a temperature of 5 ° C or higher than the bonding temperature of the composite adhesive fiber (g) and 5 ° C or lower than the melting point of the synthetic pulp (a), or 5 ° C or higher than the melting point of the binder (h) The heat treatment is preferably performed at a temperature of 5 ° C or less from the melting point of the synthetic pulp (a). When the insulator (h) is an amorphous polymer such as rubber, heat treatment is performed at the bonding temperature. It is desirable that this heat treatment be performed before the formation of the next coating layer (形成) or before the formation of the projections in order to impart mechanical strength to the porous base sheet (I).

Here, the “bonding temperature” of the composite adhesive fiber (g) refers to a temperature at which the low melting point component is melted, and the amorphous polymer is softened to develop an adhesive force. The porous base sheet (I) produced by the wet papermaking described above has a thickness force of '0.05 to ensure the electrical characteristics required for the separator and the adaptability to battery assembly. I. 0 mm, preferable properly is in the range of 0. 1 ~ 0. 4 mm, density of 0. 1 ~ 0. 6 g / cm 3, is favored properly 0. 2~ 0. 4 g / cm ³ The porous base sheet (I) having a maximum pore diameter of 200 m or less, preferably 100 m or less, is suitable.

Before forming the coating layer (Π) described later on one or both sides of the porous base sheet (I), the porous base sheet (I) is provided with convex portions on one or both sides of the porous base sheet (I). Can be formed. Examples of the method of forming the protrusion include a so-called rib formation method and a method of forming a protrusion by embossing. The method of forming these parts will be described later.

Coating layer (π) ヽ

In the present invention, the porous substrate sheet (I) may have an application layer (Π) containing an inorganic powder (d) and an acid-resistant polymer (e) on one or both sides thereof. The coating layer (Π) may be provided on the surface of the porous substrate sheet (I) opposite to the surface on which the projections are formed.

Inorganic powder (d)

The inorganic powder (d) forming the coating layer (層) is preferably an acid-resistant synthetic or natural silica-based, alumina-based or silica-alumina-based inorganic powder. Examples include powders of silica earth, synthetic silica, fused aluminum, powder and zeolite.

These inorganic powders (d) can be used alone or in combination of two or more. These inorganic powders (d) is laid preferred that the specific surface area measured by the BET method is in the range of ^{0. 1 ~ 2 5 0 m 2} Z g, average particle size 3 0 m or less of the inorganic powder (D) is preferably used. In particular, in order to ensure the porosity of the coating layer (Π) and to suppress cracking of the coating layer (Π), the average particle size is 10 m or less, and the specific surface area is 100 to 250. m ² / g of the inorganic powder (i) and the average particle diameter of 1 to 30 μm and the specific surface area of 0 :! to 50 m ² / g of the inorganic powder (ii) It is more preferable to use a mixture of at least two kinds of inorganic powders (d) having different particle diameters and specific surface areas. For example, as the inorganic powder (d), a mixture of the inorganic powder (i) of 10 to 90% by weight and the inorganic powder (ii) of 90 to 10% by weight is preferable.

By using a mixture of the inorganic powders (d) having different average particle diameters and specific surface areas, it is possible to obtain a separation battery for lead-acid batteries that is balanced in physical properties. Incidentally, the inorganic powder (i) alone tends to cause cracks in the coating layer (るため) due to too large specific surface area, and the inorganic powder (ii) alone tends to increase the electrical resistance. is there. If the specific surface area of the inorganic powder (d) is smaller than 0.1 m ² ng or the average particle size is larger than 30 m, the porous substrate sheet (I) has If the voids are filled, penetrating pores will not be formed, and if the specific surface area is greater than 250 m ² / g or the average particle size is less than 0.1 m, apply. Therefore, it becomes difficult to maintain a paste state having a necessary viscosity.

For this reason, it is preferable to use a mixture of the above inorganic powder (i) and inorganic powder (ii). Adopt such mixed use Then, the coating layer (Π) having flexibility and no cracking can be formed, and the coating layer (を持つ) having appropriate electric resistance can be formed with a relatively small basis weight.

Here, the “average particle size” is the average particle size measured by the Coulter Counter-1 measuring device using the Elect-Mouth Zone Method, and the particle size distribution is the normal particle size distribution of the powder by wet or dry classification. It is.

Acid-resistant polymer (e)

The acid-resistant polymer (e) that forms the coating layer (Π) is a synthetic resin having a glass transition temperature (Tg) of −50 to 80 ° C, which is excellent in acid resistance and oxidation resistance. Although a rubber-like material is used, a polymer having a glass transition temperature (T _g ) in the range of -5 to 70 ° C. is preferred because it is easily available. Specific examples of such preferred acid-resistant polymer (e) include:

Acrylic resin such as methyl methacrylate;

Olefin-based or gen-based polymers such as polyethylene, polypropylene and polybutadiene;

Polymers such as polystyrene, polyacrylonitrile, polyvinyl chloride, styrene-butadiene rubber, and nitrylbutadiene rubber are exemplified.

These acid-resistant polymers (e) can be used alone or in combination of two or more.

Here, the “acid resistance” of the acid-resistant polymer (e) has the same meaning as described above, and the acid-resistant polymer (e) undergoes shape change and chemical change even when immersed in an aqueous sulfuric acid solution. Polymers having no acid resistance, specifically, those having an acid resistance value of 0.6% or less as specified in JISC 222. These acid-resistant polymers (e) are mixed with water together with the inorganic powder (d) when forming the coating layer (Π), and used as a paste-like mixed solution. It is preferable to be in the emulsion or dispersion state.

Formation of coating layer (Π)

This coating layer (Π) is usually made of a paste-like mixed solution prepared by adding water to the inorganic powder (d) and the acid-resistant polymer (e), and the porous base material having no convex portions formed thereon. It is convex on the surface of the sheet (I), on the surface opposite to the surface on which the ribs of the porous substrate sheet (I) are formed, or by embossing the porous substrate sheet (I). It can be formed by applying a coater to the surface opposite to the surface on which the portion is formed, that is, the concave surface, and then drying. For example, in a coating apparatus as shown in FIG. 1, while supplying a paste-like mixture 2 to a mixing tank 3, a porous substrate sheet 1 is simultaneously coated with a coating bar coater 4 and a guide roll 5. The paste-like mixed solution 2 is applied to one surface of the porous substrate sheet 1 through the gap, and then dried, whereby the coating layer 6 can be formed.

Further, a porous substrate sheet on which these convex portions may be formed.

(I) can be immersed in the paste-like mixture to form a coating layer (π) (so-called impregnation coating method).

In the present invention, it is preferable to form the coating layer (Π) by using all over the glass.

As the paste-like mixture used for forming the coating layer (Π), the solid content of the inorganic powder (d) and the acid-resistant polymer (e) is 10 to 70% by weight. Preferably, the moisture is in the range of 30 to 90% by weight. As the solid content, the inorganic powder (d) is preferably in the range of 30 to 90% by weight, and the acid-resistant polymer (e) is preferably in the range of 10 to 70% by weight. New The use of a paste-like liquid mixture having a solid content within the above range provides excellent adhesion between the inorganic powders (d) and also does not impair the porosity of the porous substrate sheet (I). A coating layer (Π) can be formed.

The viscosity of the paste-like mixed solution is 500 to 100,000 cPs (25 ° C.) from the viewpoint of ensuring adhesion to the porous substrate sheet (I). It is preferable to be within the range.

In the preparation of the paste-like mixture, the viscosity within the above range cannot be obtained only by mixing the inorganic powder (d), the acid-resistant polymer (e) and water, and the porous base sheet (I) If the adhesiveness of the rubber is insufficient, a thickener may be added in addition to these components.

Specific examples of the thickener include sodium polyacrylate, carboxymethyl cellulose, gelatin, polyvinyl alcohol, and the like.

The coating layer (Π) formed on the surface opposite to the surface on which the projections are formed by the embossing of the porous substrate sheet (I), ie, the concave surface, has a dry basis weight of l to 200. g Z cm ² , preferably 2 ~ :! OO gcm ² , more preferably in the range of 5 to 50 gZm ² . When the coating layer (Π) is formed so that the dry basis weight is within the above range, the electric resistance value is within the appropriate range for the separation, and the laminated sheet (酸化) with improved oxidation resistance is obtained. can get. According to the experiments of the present inventors, by setting the average pore size of the laminated sheet (m) on which the coating layer (Π) is formed to be about 0.1 to 10 ^ m, an appropriate electric resistance can be obtained. It was found that a separé evening exhibiting acid resistance was obtained.

Convex part forming method

Laminated sheet without protrusions obtained as described above

(m) and the projections in the porous base sheet (I) are usually formed by a projection forming method called a rib forming method or an embossing method. Examples of the laminated sheet (m) on which the convex portions are formed include: (1) As shown in FIG. 2, the porous base sheet 1 has ribs 8 formed on the surface thereof. Laminated sheet 7 consisting of base sheet 1 and coating layer 6, (2) As shown in FIGS. 3, 4, and 5, a porous base sheet 1 having convex portions formed by enbossing. A laminated sheet 7 in which a coating layer 6 is formed on one surface opposite to the convex portion is exemplified.

Rib forming method

In the present invention, after forming a coating layer (Π) containing an inorganic powder (d) and an acid-resistant polymer (e) on at least one surface of the porous base sheet (I), At least one of the surface of the coating layer (Π) and the surface of the porous substrate sheet (I), or one surface of the porous substrate sheet (I) before forming the coating layer (層), Preferably, a plurality of ribs, for example, a substantially linear rib, may be formed.

By forming the ribs, diffusion of the electrolytic solution and release of gas generated from the electrodes can be improved. In addition, the formation of the ribs makes it difficult for the porous substrate sheet (I) to directly contact the electrode. — (I) is less susceptible to oxidative degradation due to electrode reactions.

The shape and height of the rib are not particularly limited. The ribs are usually formed on the same straight line continuously or discontinuously in a straight line, and a plurality of ribs are formed at predetermined intervals in the width direction, or are continuous or discontinuous on the same meander. It is formed in a meandering shape. The height of the rib may be about 0.2 to 2 mm, and the interval may be about 3 to 30 mm.

The material constituting the rib is not particularly limited as long as it has acid resistance and is not oxidized and deteriorated by oxygen gas generated from the electrode. An acid-resistant hot-melt resin is preferably used.

Examples of acid-resistant hot-melt resins include polyolefin-based, polyamide-based, polyester-based, ethylene-vinyl acetate copolymer-based, thermoplastic rubber-based, polyurethane-based, and epoxy-based resins. Are mentioned. These hot methylolates may be used alone or in combination of two or more.

Among these resins, a polyolefin resin having excellent oxidation resistance is preferred, and in particular, atactic polypropylene (APP) and a polyolefin resin containing polyethylene as a main component are preferred. Can be

The content of these hot melt resins is not particularly limited in the composition of the ribs, but is not less than 50% by weight from the viewpoint of ease of work such as coating. It is preferable to

It also improves the oxidation resistance and mechanical strength of the hot melt resin. For this purpose, a thermoplastic resin such as isotactic polypropylene (IPP), low molecular weight polypropylene wax or low molecular weight polyethylene wax can be blended with the hot melt type resin. In addition, an inorganic powder such as synthetic resin can be blended with the hot melt type resin in place of these thermoplastic resins, and further, such an inorganic powder can be mixed with the thermoplastic resin. It can be blended with hot melt type resin.

These thermoplastic resins and inorganic powders are usually blended with the hot melt resin in a ratio of 5 to 50% by weight.

Convex part forming method by embossing

In the present invention, the surface of the porous base sheet (I) before forming the coating layer (層) or the surface of the porous base sheet (I) layer of the laminated sheet (m) or the coating layer ( )) The 表面 part formed by embossing on the surface is formed substantially continuously on the same straight line or discontinuously in a substantially straight line, and a plurality of forces are formed at predetermined intervals in the width direction. Or a continuous or discontinuous meandering shape on the same meandering, and a plurality of forces formed at predetermined intervals in the width direction, or a plurality of hemispherical or frustoconical shapes Preferably, it is formed in

The height of the protrusions formed by embossing and the distance between the protrusions are not particularly limited. In the case where there are a plurality of convex portions formed on the same straight line or the same meandering continuously or discontinuously in a substantially linear or meandering shape in a predetermined interval, the height of the convex portions is usually 0.2 to 0.2. The distance may be about 2 mm, and the interval may be about 3 to 30 mm.

In addition, when the shape of the protrusion is a plurality of hemispheres or truncated cones, Usually, the diameter should be about 1 to 10 mm and the height of the projections should be about 0.2 to 2 mm, and the interval should be about 3 to 50 mm.

The embossing of the porous base sheet (I) or the laminated sheet (ΠΙ) is generally performed by passing these sheets between a pair of embossing rolls.

The combination of the embossing rolls used is not particularly limited as long as the shape of the convex portion can be added, and is not particularly limited. For example, a metal convex roll and a metal concave roll, and a metal convex roll may be used. Examples include a combination of a rubber concave roll, a metal convex roll and a rubber flat roll, a metal convex roll and a paper concave roll, a metal convex roll and a paper flat roll, and the like.

The conditions for embossing differ depending on the combination of the embossing rolls and the physical properties of the porous base sheet (I) or the laminated sheet (ΙΠ), but the porous substrate sheet (I) or the laminated sheet (I) m) is preferably carried out under conditions where the physical properties of the material do not change as much as possible before and after embossing. Usually, the roll temperature is from room temperature to 150 ° C, and the nip pressure between the rolls is 1 to 30 kg Z cm. ^The embossing is performed under the condition that the sheet feed speed is in the range of about 1 to 5 Om / min.

There is a merit that a convex portion can be formed more easily by a method of forming a convex portion by embossing with an embossing roll than by the above-described rib forming method. In addition, by forming the coating layer (Π) on the concave surface of the porous base sheet (I) formed by embossing, the strength of the protrusions formed by embossing is increased, and practically, It is possible to provide a lead storage battery with sufficient strength. Ku Seno Reta

The separator for a lead storage battery according to the present invention is a sheet-like separator using the laminated sheet (m) as it is, which is composed of the laminated sheet (m) on which the above-mentioned projections may be formed. It may be evening, or it may be a bag-shaped separation that was used in a bag.

The average pore size of the laminated sheet (m) used in the separation for a lead storage battery according to the present invention is preferably in the range of 0.1 to 10 m to improve the electric resistance value and the oxidation resistance. Preferred in point. That is, the average pore size

If it is less than 0.1 in, the electrical resistance of the separator increases, and if it exceeds 1, the effect of improving oxidation resistance is small. The porosity of the laminated sheet (m) is preferably 50% or more in order to reduce electric resistance.

The lead storage battery separator composed of the laminated sheet (m) according to the present invention usually has the following performance.

(1) The anode and cathode can be electrically isolated as insulators.

(2) Good diffusion of electrolyte and low electric resistance.

(3) Excellent acid resistance and heat resistance.

(4) It has the mechanical strength necessary for battery assembly and practical use.

(5) Does not elute substances harmful to battery performance.

Therefore, the separator for a lead storage battery according to the present invention is useful as a separator for an open storage battery, and is particularly preferable as a separator for an automotive storage battery.

Overnight Separation

The bag-shaped separator is, for example, a laminated sheet having no projections. (m) are overlapped or folded back and overlapped, and the other side end except for one side end is bonded by a fusion seal using ultrasonic waves or heating, or a mechanical seal such as gear crimping, etc. m)) in the form of a bag.

Further, in the case of a laminated sheet (m) having a convex portion, for example, the laminated sheet (m) should have the surface on which the convex portion is formed or the surface on which the convex portion is not formed inward. The other side end except for one side end is formed into a bag by a fusion seal using ultrasonic waves or heating, or a mechanical seal using gear crimping, etc. By forming, a bag-like separator can be obtained.

As described above, when forming the laminated sheet (π) into a bag shape, the surface on which the convex portion such as a rib is formed is overlapped so as to come to the inside of the bag, or folded back and overlapped. It may be superimposed on the outside of the bag, or may be folded back and superimposed. For example, in a lead-acid battery, when the anode plate is placed in a bag-shaped separator made of laminated sheets (m), make sure that the ribs and other protrusions are inside the bag-shaped separator. When the cathode plate is placed in the bag-shaped separator, it is preferable that the protrusions such as ribs are located outside the bag-shaped separator.

An example of the structure of the bag-shaped separator is disclosed in detail in Japanese Patent Application Laid-Open No. 1991/1991 filed by the present applicant. The invention's effect According to the present invention, it is possible to provide a sheet-like or bag-like separator for a lead storage battery having low electric resistance and excellent oxidation resistance, and at least one of the surfaces has a convex portion. It is possible to provide a sheet-like and bag-shaped separator that has been formed and a sheet- and bag-shaped separator that has no projections formed at all. Example

Hereinafter, the present invention will be described with reference to examples. The present invention is not limited to these examples.

Example A-1

<Preparation of porous substrate sheet,

As synthetic pulp (a) in which the constituent fibers are in a multi-branched state, polyethylene synthetic pulp (melting point = 135 ° C, average fiber length = lmm, freeness = 3 seconds Zg) 30% by weight,

As acid-resistant inorganic powder (b), silica earth 45 weight%,

Synthetic fibers (f) polyester fiber 2 3 wt Q ₀ as, and Pa, and the Lee Nda (h) a styrene - molded butadiene copolymer Gomubai Sunda wet papermaking method sheet comprising a single 2 wt%, then 1 2 5 ° C subjected to a drying and heat treatment through the set drum dryer, thickness 0. 2 5 mm, density 0. ³ 5 g Z cm 3 of the porous substrate sheet (porosity = 7 6% , Average pore size = 15 ju maximum pore size = 50 m).

Preparation of paste-like mixture for coating layer formation \

As the inorganic powder (d), an average particle diameter of 1 m, a specific surface area 2 2 0 m ² Bruno g silica 4% by weight, average particle size 15 / m, specific surface area 2 m ² g g silica earth 6 weight ⁰ , average particle size 3 / m, specific surface area 3 m ² g 10% by weight of light,

The acid-resistant polymer (e) has a glass transition point (T g) of 1.5% by weight of a solid content of an acrylic resin emulsion having a glass transition point (T g) of 70 ° C. -5 ° C styrene-butadiene copolymer latex (SBR) 3% by weight of emulsion as solids,

A paste-like mixed solution (viscosity: 400 cps (25 ° C.)) consisting of 0.5% by weight of sodium polyacrylate and 75% by weight of water was prepared as a thickener.

This base-like mixed solution was applied to one surface of the porous substrate sheet using the application apparatus shown in FIG. 1, and then heated and dried at 150 ° C. to obtain a dry basis weight of 4 A coating layer of 0 g Z m ² was formed. In this application, as shown in Fig. 1, the paste-like mixed solution 2 is supplied to the mixing tank 3 in the coating apparatus, and at the same time, the porous substrate sheet 1 is simultaneously coated with the coating bar 4 and the guide roll 5. Between the two.

Then, using a hot-melt resin (“Asahi Tack TD3—176” (trade name) manufactured by Asahi Chemical Synthetic Co., Ltd.) on the coating surface, the rib height was 0.8 mm and the rib spacing was 1 mm. A plurality of continuous linear ribs were formed so as to have a thickness of 0 mm to obtain a lead storage battery separator (average pore diameter = l ^ m). Separator characteristics of the obtained separator were measured by the following method. The results are shown in Table 1.

<Method of measuring separator characteristics: (1) Thickness: measured according to JISC 222

(2) Electric resistance value Measured according to JISC2313.

(3) Oxidation resistance time An anode plate and a cathode plate are placed in a test container, and a 50 mm x 50 mm Seno and temperature sample is set between them. Load was applied. In this state, 100 ml of sulfuric acid aqueous solution (specific gravity at 20: 1.3) was put into the vessel, and a DC current of 2.5 A was passed at 50 ° C, and the terminal voltage between both electrodes was 2 The time during which 6 V or less or the voltage difference dropped 0.2 V within 2 hours was measured, and this was defined as the oxidation resistance time.

Example A-2

Preparation of paste-like mixture for forming coating layer

As inorganic powder (d), 10% by weight of synthetic silica having an average particle size of 1 m and a specific surface area of 220 m ² / g, an average particle size of 15 ^ m, and a specific surface area of 2 m ² / g Kay Sou soil 6 wt%, average particle diameter 3 m, a specific surface area of 3 m ² Roh 'g Pas one line preparative 4% by weight of,

The acid-resistant polymer (e) has a glass transition point (T g) of 70% at 70 ° C as a solid content of 2% by weight as a solid, and a glass transition point (T g). -Paste-like mixture consisting of 2.5% by weight of SBR emulsion at 5 ° C as solids, 0.5% by weight of sodium polyacrylate as a thickener, and 75% by weight of water <½ A liquid (viscosity 450 000 cPs (25 ° C)) was prepared.

Formation of coating layer and formation of rib One side of the same porous substrate sheet as in Example A-1 was applied using the coating apparatus shown in Fig. 1 in the same manner as in Example A-1, and then heated and dried at 150 ° C. A coating layer having a dry basis weight of 20 gm ² was formed.

Subsequently, a plurality of continuous linear ribs were formed in the same manner as in Example 1 to obtain a lead storage battery separator (average pore diameter = 2 ^ m).

Separator characteristics of the obtained separator were measured by the above method. The results are shown in Table 1.

Example A-3

<Preparation of porous substrate sheet

As synthetic pulp (a), polyethylene synthetic pulp (average fiber length = 1 mm, freeness = 3 seconds Z g) 30% by weight,

45% by weight of synthetic silica as acid-resistant inorganic powder (b),

23% by weight of composite heat-bonding fiber composed of polypropylene and polyethylene (melting point: 110 ° C) as the composite adhesive fiber (g), and styrene as the binder (h) A butadiene copolymer rubber binder consisting of 2% by weight; and

The thickness 0. 2 0 mm, density 0. ³ 5 g / cm 3 of the porous substrate sheet scratch Bok (porosity = 7 6%, an average pore diameter = 1 3 ^ m, a maximum pore size = 4 5 ^ m) Was prepared by a wet papermaking method.

Preparation of paste mixture for coating layer formation \

As inorganic powder (d), synthetic silica having an average particle diameter of 1 βm and a specific surface area of 220 m ² /10% by weight, an average particle diameter of 15 m, and a specific surface area of 2 m ² , 'g 18% by weight

The acid-resistant polymer (e) has a glass transition point (Tg) of -5 ° C. 11.5% by weight of BR emulsion as solids,

A paste-like mixture (viscosity: 500 cps (25)) consisting of 0.5% by weight of sodium polyacrylate and 60% by weight of water was prepared as a thickener. .

<Formation of coating layer and formation of ribs

This paste-like mixed solution was applied to one surface of the porous substrate sheet using the coating apparatus shown in FIG. 1 in the same manner as in Example A-1.

The resultant was dried by heating at ° C to form a coating layer having a dry basis weight of 45 g nom ² . Next, a plurality of continuous linear ribs were formed in the same manner as in Example 1 to obtain a lead storage battery separator (average pore size = 1 Hm).

Separation characteristics of the obtained separation were measured by the above method. The results are shown in Table 1.

Example A-4

<Preparation of a paste mixture for forming a coating layer,

As inorganic powder (d), synthetic silica having an average particle size of 1 βm and a specific surface area of 220 m ² / g 8 weight ¹¹ , an average particle size of 15 ^ m, and a specific surface area of 2 m ² / 20% by weight of g

As the acid-resistant polymer (e), an acrylic resin having a glass transition point (Tg) of -5 ° C is 3.5% by weight as a solid content, and the glass transition point (Tg) is 3.5% by weight. A paste-like liquid mixture consisting of 8% by weight of SBR emulsion at 6 ° C as solids, 0.5% by weight of sodium polyacrylate as a thickener, and 60% by weight of water ( A viscosity of 500 000 cPs (25 ° C) was prepared.

Coating layer and rib formation One side of the same porous substrate sheet as in Example A-3 was coated using the coating apparatus shown in FIG. 1 in the same manner as in Example A-1, and then dried by heating at 150 ° C. A coating layer having a basis weight of 25 gm ² was formed.

Next, a plurality of continuous linear ribs were formed in the same manner as in Example 1 to obtain a lead storage battery separator (average pore diameter = 2 ^ m).

Comparative Example A-1

As a porous base sheet, a nonwoven fabric made of polyester fiber having a basis weight of 40 g nom ² , a thickness of 0.2 mm, and a density of 0.2 g Z cm ³ was used. In the same manner as in Example 1, a coating layer having a basis weight of 100 g / m ² and comprising the same inorganic powder and the acid-resistant polymer as in Example 1 was formed.

Next, a plurality of continuous linear ribs were formed in the same manner as in Example 1 to obtain a comparative separator (average pore diameter = 15 m).

Comparative Example A-2

The same porous substrate sheet one Bok Example 1, impregnated with § click Riruemaruji Yo emissions 2 0 wt% aqueous solution, and dried by heating 1 2 0 ^D C.

Next, a plurality of ribs were formed in the same manner as in Example 1 to obtain a separator for comparison (average pore diameter = 7 m).

The separation properties of the obtained separator were measured by the above method. The results are shown in Table 1. table 1

Example A-1 Example A-2 Example A-3 Example A-4 Comparative Example A-1 Comparative Example A-2 Porous substrate sheet

Thickness mm) 0.25 0.25 0.20 0.20 0.20 0.25 Acrylema Dry basis weight (gZm ² ) 40 20 45 25 1 00 Revolution impregnation Rib formation Yes Yes Yes Yes Yes Yes Electric resistance

(Ω. Dm ² Z) 0.0007 0.0006 0000.0007 0.0005 0.00 1 0 0.00 1 3 Oxidation resistance time

(hrs / sheet) 330 300 340 305 1 60 1 40

As is clear from Table 1, the separation of this example has lower electric resistance and extremely excellent oxidation resistance as compared with the comparative example. Example B-1

Preparation of porous base sheet

As synthetic pulp (a), polyethylene synthetic pulp (manufactured by Mitsui Petrochemical Industries, Ltd., trade name SWPEST-2, melting point: 135 ° C) 30% by weight <%

As the acid-resistant inorganic powder (b), synthesized Li Ca (Japan Shi Li Ca Co., trade name Nipsil NS - T) 4 5 Weight ^0/0,

And a composite adhesive fiber (g), polypropylene with polyethylene (melting point 1 1 0 ° C) and composite thermal bonding fibers consisting (Daiwaboupori Te click trade name NBFE type) 2 3 Weight ⁰ '0 , and

As a binder (h), a styrene-butadiene copolymer rubber binder (manufactured by Nippon Zeon Co., Ltd., trade name: Nipol LX430), a sheet consisting of 2% by weight, is formed by a wet papermaking method. , Followed by drying and heat treatment through a drum dryer set at 125 ° C,

The thickness 0. 2 0 mm, density 0. ³ 5 g Z cm 3 of the porous substrate sheet one Bok (porosity = 7 6%, an average pore diameter = 1 0 m, a maximum pore size = 4 0 ^ m) Preparation did.

Preparation of paste-like mixture for coating layer formation>

As inorganic powder (d), 10% by weight of synthetic silica having an average particle size of 1 βm and a specific surface area of 220 m ² / g, an average particle size of 15 ^ m, and a specific surface area of 2 m ² / g g of diatomaceous earth 5% by weight, As the acid-resistant polymer (e), an acrylic resin emulsion (Polytron FX—2210) manufactured by Asahi Kasei Kogyo Co., Ltd., having a solid content of 10% by weight, and

A paste-like mixed solution (viscosity: 40000 cPs (25 ° C)) consisting of 75% by weight of water was prepared.

Convex part formation by embossing>

Using two embossing rolls consisting of a combination of a metal convex roll and a paper concave roll, the metal convex roll temperature is 130 ° C, the nip pressure between the rolls is 10 kg / cm, and the base sheet feeding speed Under the condition of 5 m / 'minute, the embossing was performed by passing the porous substrate sheet between the two embossed mouths. By this embossing, a plurality of linear convex portions continuous on the same straight line could be formed at intervals of 10 mm. The total thickness of the porous base sheet including the embossed protrusions was 1.0 mm.

<Formation of coating layer ヽ

The paste-like mixed solution was applied to the embossed concave side of the embossed sheet obtained as described above using the application device shown in FIG. 1 in the same manner as in Example A-1. The resultant was dried by heating at ° C to form a coating layer having a dry basis weight of 30 g / m ² , thereby obtaining a lead storage battery separator (average pore diameter = 2 m).

Separator characteristics of the obtained separator were measured by the above method. The results are shown in Table 2.

Example B-2

Preparation of paste-like mixture for coating layer formation: As inorganic powder (d), synthetic silica having an average particle diameter of 1 βm and a specific surface area of 220 m ² , g was 10% by weight, an average particle diameter of 15 ^ m, and a specific surface area of 2 m ^2. 5% by weight of g

As an acid-resistant polymer, Acryl Resin Emulsion (made by Asahi Kasei Corporation, trade name: Polytron FX-2210) has a solid content of 8 weight ⁰ and a glass transition point (T g) — 5 ° C styrene-butadiene copolymer latex (SBR) Paste-like liquid mixture consisting of 2% by weight of solids and 75% by weight of water (viscosity of 400 c P s (25 ° C.)) was prepared.

Convex formation by embossing

Example B—Using the same porous substrate sheet as in 1, using two embossing rolls composed of a combination of a metal convex roll and a paper concave roll, the metal convex roll temperature was set at 135 ° C and the roll was rolled. Embossing is performed by passing a porous substrate sheet between the two embossing ports under the conditions of a nip pressure of 5 kg Z cm and a substrate sheet feeding speed of 5 m / min. Done. By this embossing, a plurality of linear projections continuous on the same straight line could be formed at intervals of 10 mm. The total thickness of the porous base sheet including the embossed protrusions was 0.8 mm.

The embossed sheet was coated on the concave side of the embossed sheet using the coating apparatus shown in FIG. 1 in the same manner as in Example A-1, then dried by heating at 150 ° C. to obtain a dry basis weight of 45 g / By forming two types of coating layers, m ² and 100 g Z m ² , a lead-acid battery separator having an average pore diameter of 2 m and a separator for a lead-acid battery having an average pore diameter of 1 m were obtained. Separator characteristics of the obtained separator were measured by the above method. The results are shown in Table 2.

Example B-3

<Preparation of porous substrate sheet

. The thickness of the porous substrate sheet 0 except that the 2 5 mm, Example B -. 1 with the same porous substrate sheet one preparative (density ^{= 0 3 5 g / cm 3} , the porosity = 7 690, average pore size = 10 m, maximum pore size = 40 m) were prepared by a wet papermaking method.

Preparation of paste-like mixture for coating layer formation \

As inorganic powder (d), 7% by weight of synthetic silica having an average particle size of 1 nm and a specific surface area of 220 m ² / g, an average particle size of 15 ^ m and a specific surface area of 2 m ² _Zg 8% by weight

As the acid-resistant polymer (e), an acrylic resin emulsion (Polytron F X—2 210) manufactured by Asahi Kasei Kogyo Co., Ltd., having a solid content of 10% by weight, and

A paste-like mixed solution (viscosity: 400 cps (25 ° C.)) consisting of 75% by weight of water was prepared.

Convex part formation by round boss processing>

Using two embossing rolls consisting of a combination of a metal convex roll and a paper concave roll, the metal convex roll temperature was 130 ° C, the nip pressure between the rolls was 10 kg Z cm, Embossing was performed by passing the porous substrate sheet between two embossing rolls under the conditions of a feed speed of 5 mZ. By this embossing, it was possible to form a plurality of discontinuous linear projections on the same straight line at intervals of 10 mm. The total thickness of the porous base sheet including the embossed protrusions was 1.0 mm.

Forming a coating layer>

The paste-like mixture was applied to the embossed concave side of the embossed sheet using the application apparatus shown in FIG. 1 in the same manner as in Example A-1, and then dried by heating at 150 ° C. Two types of coating layers having a dry basis weight of 40 gm ² and 50 g / m ² were formed to obtain two types of separation batteries for lead-acid batteries (average pore diameter = 2 u rn).

Separation characteristics of the obtained separation were measured by the above method. The results are shown in Table 2.

Example B-4

<Preparation of paste-like mixed solution for coating layer formation,

As an inorganic powder (d), a 7% by weight synthetic silica having an average particle size of 1 βm and a specific surface area of 220 m ² /, a gay particle having an average particle size of 15 m and a specific surface area of 2 m ² Zg 8% by weight of soil

As the acid-resistant polymer (e), acrylic resin emulsion (trade name: Polytron FX—2210, manufactured by Asahi Kasei Kogyo Co., Ltd.) is 5% by weight as a solid content, and has a glass transition point. (T g) — 5 ° C styrene-butadiene copolymer latex (SBR) 5% by weight as solid content of emulsion, and

Convex formation by embossing

Using the same porous substrate sheet as in Example B-3, a metal convex roll was used. Using two embossing rolls, which are a combination of a concave roll made of paper, a metal convex roll temperature of 135 ° C, a nip pressure between rolls of 5 kgcm, and a substrate sheet feed speed of 5 m / min. Under the conditions, an embossing process was performed by passing a porous substrate sheet between two embossing holes. By this embossing, it was possible to form a plurality of discontinuous linear projections on the same straight line at intervals of 10 mm. The total thickness of the porous base sheet including the embossed protrusions was 0.8 mm.

Coating layer formation>

The paste-like mixture was applied to the embossed concave side of the embossed sheet using the coating apparatus shown in FIG. 1 in the same manner as in Example A-1, and then dried by heating at 150 ° C. , two kinds of coating layer having a dry basis weight of 5 O g Zm ² and 1 0 0 g / m ² was formed, the average pore size of 2 m lead acid battery separator Isseki and average pore size of 1 mu m lead acid battery separator evening of I got Separation characteristics of the obtained separation were measured by the above method. The results are shown in Table 2.

Comparative Example B-1

Using the same porous substrate sheet as in Example B-1 and using two embossing rolls composed of a combination of a metal convex roll and a paper concave roll, the metal convex roll temperature was 130 ° C. C, Emboss by passing a porous substrate sheet between the two embossing holes under the conditions of 10 kg / cm nip pressure between rolls and a substrate sheet feed speed of 5 m / min. Processing was performed to obtain a comparative separator (average pore diameter = 10 m). By embossing, it was possible to form a plurality of linear projections on the same straight line at intervals of 10 mm. The porous substrate sheet including the embossed protrusions The total thickness of the bird was 1. O mm.

Comparative Example B-2

Using the same porous substrate sheet as in Example B-3, using two embossing rolls composed of a combination of a metal convex roll and a paper concave roll, a metal convex roll temperature of 135 ° C, Embossing is performed by passing a porous substrate sheet between two embossing rolls under the conditions of a nip pressure between rolls of 5 kg / cm and a substrate sheet feed speed of 5 m / 'min. Thus, a comparative separator (average pore size = 10 m) was obtained. By embossing, it was possible to form a plurality of discontinuous linear projections on the same straight line at intervals of 10 mm. The total thickness of the porous base sheet including the embossed projections was 1.0 mm.

A lead-acid battery was constructed using each separator of Examples A-1 to 4 and Examples B-1 to 4, and a battery life test (SAEJ240Cycle) was performed.

As a result of performing Life Testing, the cycle life was equal to or longer than that of a commercially available polyethylene film separator. Table 2

Example B-1 Example B-2 Example B-3 Example B-4 Comparative Example B-1 Comparative Example _ _2

^ Porous material sheet

h 匾 f-mi ⁰ ^ (m 0, 20 0. 20 0. 25 0. 25 0. 20 0.25 Embossed shape i car Overall speed Continuous Discontinuous Discontinuous Continuous ^ ^ "!

Straight line straight line straight line business τ H '

j ^ -ffj 'v ΙΠ ill J π 0.8.1.0.0.8 * w 1 Ω 涂; product? ^ Bizoen 7 ffCi field to fl 一人 alone 1 kH / Mr.

iJi

M ^, no 1 0 1 0 7 7

> r Seo L. Li 5 8 8

Acryl resin emalzico solids) 1 0 8 1 0 5

S BR Emarjoz solids) 2 5

Water 75 75 75 75 Dry basis weight (gZm ² ) 30 45 1 00 4 0 50 50 1 00

Electric resistance

(Ω · dm ² / sheet) 0.0005 0.0006 0.0007 0.0007 0.0007 0.0006 0.0008 0.0004 0.0005 oxidation time

(hrs / 300 330 360 330 330 34 0 370 90 1 1 0

As is clear from Table 2, the separator of this example has a low electric resistance, and has extremely excellent oxidation resistance as compared with the comparative example in which only embossing is performed.

Claims

Claim scope

1. A porous pulp made of a synthetic pulp (a) in which the constituent fibers are in a multi-branched state, an acid-resistant inorganic powder (b) and Z or an acid-resistant inorganic fiber (c), produced by a wet paper-making method. At least one side of the base sheet (I) is composed of a laminated sheet (ΠΙ) formed with a coating layer (Π) containing an inorganic powder (d) and an acid-resistant polymer (e). Features lead-acid battery seno and writer.

2. The lead storage battery separator according to claim 1, wherein a convex portion is provided on one or both surfaces of the laminated sheet (m).

3. The convex portion is formed on the surface of the porous base sheet (I) layer of the laminated sheet (m) continuously or discontinuously on substantially the same straight line. 2. Separation for lead-acid batteries according to paragraph 2 of the paragraph.

4. The lead-acid battery separator according to claim 2, wherein the convex portion is formed by hot-melt resin in a rib shape.

5. The lead storage battery separator according to claim 2, wherein the projections are formed by embossing the porous base sheet (I).

6. The protrusions are formed on one surface of the porous base sheet (I) in a continuous or discontinuous manner on substantially the same straight line by embossing, and the porous base sheet (I) 3. The separator for a lead-acid battery according to claim 2, wherein the coating layer (Π) is formed on a surface opposite to a surface on which the convex portions are formed.

7. The lead storage battery separator according to any one of claims 1 to 6, wherein the laminated sheet (m) is formed in a bag shape.

8. The porous substrate sheet (I),

Synthetic pulp (a) 5 to 70% by weight,

Synthetic fiber (f) and / or composite adhesive fiber (g) 5-50% by weight

The lead storage battery separator according to any one of claims 1 to 7, wherein the separation is for a lead storage battery.

9. The porous substrate sheet (I),

Synthetic pulp (a) 5 to 70% by weight,

Synthetic fiber (f) and composite or composite adhesive fiber (g) 5 to 50 Weight percent,

A binder (h) having a melting point lower than the melting point or the decomposition temperature of the synthetic pulp (a) or exhibiting an adhesive force at the above-mentioned temperature;

The lead-acid battery separator according to any one of claims 1 to 7, wherein the separator comprises:

10. The lead-acid battery according to any one of claims 1 to 9, wherein the dry basis weight of the coating layer (Π) is in the range of 5 to 50 gm ^2. For separator.

11. The coating layer (Π), the inorganic powder (d) is composed of 30 to 90% by weight, and the acid-resistant polymer (e) is composed of 10 to 70% by weight. Separation for lead-acid batteries according to any one of the paragraphs 1 to 10 — evening.

1 2. The inorganic powder (d) constituting the coating layer (Π) has an average grain size of 10 Hm or less and a specific surface area of 100 to 250 m ² / g. Inorganic powder (i) an inorganic powder having an average particle size of 10 to 90% by weight and a specific surface area of 0.1 to 50 m ² / g; The separator for a lead storage battery according to any one of claims 1 to 11, wherein the separator is a mixture of 0 to 10% by weight.

1 3. The average pore size of the laminated sheet (m) is in the range of 0.1 to 10 μm. The separator for a lead-acid battery according to any one of claims 1 to 12, characterized in that the separator is located within the separator.

1 4. Synthetic pulp (a), whose constituent fibers are in a multi-branched state, and acid-resistant inorganic powder (b) and Z or acid-resistant inorganic fiber (c) are dispersed in a medium and wet-laid. A porous substrate sheet (I) is prepared, and then the inorganic powder (d) and the acid-resistant polymer (e) have a solid concentration of 1%.

A paste-like mixed solution prepared by adding water to a concentration of 0 to 70% by weight is applied to at least one side of the porous substrate sheet (I), dried, and dried. ) To form a laminated sheet (m).

1 5. The porous substrate sheet (I)

Synthetic pulp (a) 5 to 70% by weight,

15. The method for producing a separation battery for a lead-acid battery according to claim 14, wherein the method comprises:

1 6. The porous substrate sheet (I),

Synthetic pulp (a) 5 ~ 70 weight 重量,

Acid resistant inorganic powder (b) and / or acid resistant inorganic fiber (c) 5 ~ -5i-

60% by weight,

A synthetic fiber (f) and / or a composite adhesive fiber (g) of 5 to 5 °% by weight;

A binder (h) having a melting point lower than the melting point or the decomposition temperature of the synthetic pulp (a), or a binder (h) exhibiting adhesive force at the above-mentioned temperature of 0.5 to 10% by weight;

15. The method for producing a lead-acid battery separator according to claim 14, wherein the method comprises:

17. The porous substrate sheet (I) having a force, a porosity of 50% or more, and an average pore diameter of 0.5 to 20 zm. 16. A method for producing a separator for a lead storage battery according to any one of the above items 16.

1 8. The mixing ratio of the inorganic powder (d) and the acid-resistant polymer (e) constituting the solid content in the paste-like mixed solution [(d) (e) I is 30 Z70-9 The method for producing a separator for a lead-acid battery according to any one of claims 14 to 17, wherein the method is 0/10.

19. The above paste-like mixture is applied to at least one side of a porous substrate sheet (I) using a coater. The method for producing a lead storage battery separator according to any one of the above items.

20. The coating layer is formed on at least one side of the porous base sheet (I). After forming the laminated sheet (m) by forming (π), it is necessary to bond a linear rib to one or both surfaces of the laminated sheet (in) using a hot melt type resin. The method for producing a lead storage battery separator according to any one of claims 14 to 19, characterized by the above-mentioned.

2 1. After producing the porous substrate sheet (I) by wet papermaking or after producing the laminated sheet (m), the porous substrate sheet (I) is formed. Heat treatment at a temperature above the bonding temperature of the composite adhesive fiber (g) and below the melting point of the composite pulp (a), or at a temperature at which the binder (h) force develops adhesive force. 20. The method for producing a lead storage battery separator according to any one of claims 14 to 20.

2 2. After manufacturing the porous substrate sheet (I) by wet papermaking, an approximately linear convex portion is formed on the porous substrate sheet (I) using an embossing roll. An embossing process for forming a continuous or discontinuous shape is performed. Then, the inorganic powder (d) and the acid-resistant polymer ( e) A paste-like mixed solution prepared by adding water so that the solid content concentration becomes 10 to 70% by weight is applied, and dried to form a coated layer (Π), and a laminated sheet (ΙΠ) is formed. The method for producing a lead-acid battery separator according to any one of claims 14 to 19, characterized in that:

2 3. The porous base sheet (I) was manufactured by wet papermaking. Then, at a temperature not lower than the bonding temperature of the composite adhesive fiber (g) constituting the porous base sheet (I) and not higher than the melting point of the synthetic pulp (a), the binder (h) has an adhesive force. Heat treatment at a temperature that develops, and then embossing is performed to form a substantially linear convex portion on the porous substrate sheet (I) using an embossed hole.

Next, the solid content concentration of the inorganic powder (d) and the acid-resistant polymer (e) is 10 to 70 on the surface of the porous substrate sheet (I) opposite to the surface on which the projections are formed. A paste-like mixed solution prepared by adding water to a concentration of 1% by weight, followed by drying to form a coating layer (Π) to form a laminated sheet (m). Item 10. The method for producing a lead storage battery separator according to any one of Items 4 to 19.

24. After manufacturing the laminated sheet (m), the laminated sheet (m) is subjected to embossing using an embossing roll to form a substantially linear convex portion continuously or discontinuously. Item 14. The method for producing a lead-acid battery separator according to any one of Items 1 to 19.

25. The laminated sheet (ΠΙ) is overlapped, a side end thereof is sealed to form one opening, and a bag-like shape is formed. 6. The method for producing the separation for lead-acid batteries according to any one of the items 5 to 5.