Anion conducting membrane

Abstract

Provided is a material capable of further extending the life of a cell including a zinc species as a negative electrode active material. The present invention relates to an anion conducting membrane formed using an anion conducting membrane-forming material, the anion conducting membrane-forming material including a conjugated diene based polymer and/or a (meth)acrylic based polymer, and a compound containing at least one element selected from Groups I to XVII of the periodic table, the anion conducting membrane having a cross-section in which a ratio of a combined area of particles of the compound containing at least one element selected from Groups I to XVII of the periodic table to a combined area of the components of the anion conducting membrane-forming material other than the compound (particles of the compound/components of the anion conducting membrane-forming material other than the compound) is 70/30 to 30/70.

Claims

1. An anion conducting membrane formed using an anion conducting membrane-forming material, the anion conducting membrane-forming material comprising: a conjugated diene based polymer and/or a (meth)acrylic based polymer; and a compound containing at least one element selected from Groups I to XVII of the periodic table, the anion conducting membrane having a cross-section in which a ratio of a combined area of particles of the compound containing at least one element selected from Groups I to XVII of the periodic table to a combined area of the components of the anion conducting membrane-forming material other than the compound (particles of the compound/components of the anion conducting membrane-forming material other than the compound) is 70/30 to 30/70, the (meth)acrylic based polymer containing as a major constituent a monomer unit derived from a C1-C12 alkyl group-containing (meth)acrylic acid alkyl ester monomer, and the anion conducting membrane satisfying a value X represented by the following equation (1) of 1000 or more: $\begin{array}{cc}X=0.005\frac{T^{2}F}{L}& \left(1\right)\end{array}$ wherein T represents the air permeance (s); F represents the piercing strength (N); represents the density (g/cm.sup.3); and L represents the average membrane thickness (m).

2. The anion conducting membrane according to claim 1, wherein the particles of the compound containing at least one element selected from Groups I to XVII of the periodic table in the cross-section of the anion conducting membrane have an average cross-sectional particle size of 0.1 to 1.0 m.

3. The anion conducting membrane according to claim 1, wherein the compound containing at least one element selected from Groups I to XVII of the periodic table is at least one compound selected from the group consisting of oxides, hydroxides, layered double hydroxides, and phosphoric acid compounds.

4. The anion conducting membrane according to claim 1, wherein the compound containing at least one element selected from Groups I to XVII of the periodic table is a hydroxide and/or layered double hydroxide.

5. The anion conducting membrane according to claim 1, wherein the conjugated diene based polymer is a styrene-butadiene based copolymer.

6. The anion conducting membrane according to claim 1, wherein the anion conducting membrane-forming material further comprises at least one selected from the group consisting of halogen-containing polymers, carboxy group-containing polymers, hydroxy group-containing polymers, and polyolefins.

7. The anion conducting membrane according to claim 1, wherein the membrane has a multilayer structure.

8. The anion conducting membrane according to claim 1, wherein the membrane has a liquid absorption rate of 1% or more for a 6.7 mol/L KOH aqueous solution saturated with zinc oxide.

9. A cell component comprising the anion conducting membrane according to claim 1.

10. The cell component according to claim 9, wherein the cell component is a separator.

11. A cell comprising the cell component according to claim 9.

12. The anion conducting membrane according to claim 1, wherein the conjugated diene based polymer contains at least one functional group selected from the group consisting of an ester group, a hydroxy group, and a carboxy group.

13. The anion conducting membrane according to claim 1, wherein the conjugated diene based polymer has a glass transition temperature of 20 C. or higher.

14. The anion conducting membrane according to claim 1, wherein the conjugated diene based polymer has a glass transition temperature of 50 C. or lower.

15. The anion conducting membrane according to claim 1, wherein the proportion by mass of the conjugated diene based polymer and the (meth)acrylic based polymer falls within the range of 1% by mass or more and 99% by mass or less per 100% by mass of the anion conducting membrane-forming material.

16. A separator comprising a laminated structure of the anion conducting membrane according to claim 1 and an additional separator member other than the anion conducting membrane.

17. The separator according to claim 16, wherein the additional separator member is non-woven fabric.

18. The cell according to claim 11, wherein the cell comprises a water-containing electrolyte solution.

19. The cell according to claim 11, wherein the cell comprises an aqueous electrolyte solution.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows the cross-section of the 100-m-thick anion conducting membrane prepared in Example 1-1 observed with a scanning electron microscope.

(2) FIG. 2 shows the cross-section of the 100-m thick membrane prepared in Comparative Example 1-1 observed with a scanning electron microscope.

(3) FIG. 3 is a graph showing the results of charge and discharge evaluation in Example 1-1 and Comparative Examples 1-1 and 1-2.

DESCRIPTION OF EMBODIMENTS

(4) The invention is described in more detail below with reference to examples, but is not limited thereto. Unless otherwise mentioned, the term part(s) means part(s) by weight and % means % by mass.

(5) The following describes the measurement methods employed in the examples.

(6) <Air Permeance>

(7) In the examples, the air permeance (s) was measured in accordance with the Oken method (JIS P 8117) using an oken type air-permeability & smoothness tester KY-55 produced by Asahi Seiko Co., Ltd., and the measurement values were averaged.

(8) The upper limit of the measurement time was set to 30,000 s. When the measurement time exceeded this upper limit, the air permeance was regarded as 30,000 s. That is, in the examples, an air permeance of 30,000 s means an air permeance of at least 30,000 s. Therefore, the value X determined using such an air permeance means the minimum estimated value X.

(9) <Piercing Strength>

(10) The piercing strength (N) was measured in accordance with JIS Z 1707-1997 using a digital force gauge ZTA-50N (produced by Imada Co., Ltd.). A specimen was fixed, and pierced with a needle-like jig having a diameter of 1.0 mm and a semicircular tip shape with a radius of 0.5 mm at a rate of 505 ram/min. The maximum stress generated until the tip of the jig penetrated through the specimen was measured. The maximum stress values of five or more specimens were averaged.

(11) <Density>

(12) The density (g/cm.sup.3) of an anion conducting membrane was determined by measuring the mass and the volume of a specimen of the membrane, and dividing the mass by the volume. The volume of the specimen was determined from the length and the width thereof measured using a caliper and the thickness thereof measured in accordance with the following method of measuring the membrane thickness. After the determination of the volume, the mass of the specimen was measured using a precision balance (four decimal places).

(13) <Thickness of Membrane>

(14) The thicknesses (m) of an anion conducting membrane and a coating made of an insulating substance were measured using a film thickness meter (trade name: Digimatic Indicator 543-394 produced by Mitutoyo Corporation). The thickness was measured at three points of a specimen, and the resulting values were averaged.

(15) <Calculation of Value X>

(16) The value X was determined using the following equation (1), where T (s) represents the air permeance, F (N) represents the piercing strength, (g/cm.sup.3) represents the density, and L (m) represents the thickness of a membrane. They were determined by the above-described methods.

(17) $\begin{array}{cc}X=0.005\frac{T^{2}F}{L}& \left(1\right)\end{array}$
<Liquid Absorption Rate>

(18) Ten square specimens with a size of 25 mm25 mm were randomly cut from an anion conducting membrane, and the masses (M.sub.b) of the dried specimens and the masses (M.sub.a) of the specimens after immersion overnight in a 6.7 mol/L KOH aqueous solution saturated with zinc oxide were measured to determine the liquid absorption rate values. These values were averaged to determine the liquid absorption rate.

(19) <Degree of Swelling>

(20) Ten square specimens with a size of 25 mm25 mm were randomly cut from an anion conducting membrane, and the thicknesses (T.sub.b) of the dried specimens and the thicknesses (T.sub.a) of the specimens after immersing overnight in a 6.7 mol/L KOH aqueous solution were measured to determine the values of degree of swelling. These values were averaged to determine the degree of swelling.

(21) <Resistance Value>

(22) The resistance value () was measured under the following conditions.

(23) Number of cells placed: Five cells (average)

(24) Composition of Each Cell

(25) Working electrode: Ni plate

(26) Counter electrode: Ni plate

(27) Electrolyte solution: 6.7 mol/L KOH aqueous solution saturated with zinc oxide

(28) Measurement sample: immersed in the electrolyte solution overnight

(29) Effective area: 15 mm

(30) AC impedance was measured. The prepared test object was allowed to stand in a thermostatic bath at 25 C. for 30 minutes, and AC impedance was measured under the following conditions.

(31) Applied voltage: 10 mV vs. open circuit voltage

(32) Frequency domain: 100 kHz to 100 Hz

(33) The resistance value (R) was determined by the following formula using an intercept component (Ra) obtained from the impedance and an intercept component (Rb) in the case of using no measurement sample.
R=(RaRb).
<Charge and Discharge Test>

(34) Zinc oxide powder (produced by Mitsui Mining and Smelting Co., Ltd.), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), and carbon powder (trade name: Ketjen Black EC600JD produced by Lion Specialty Chemicals Co., Ltd.) were kneaded at a ratio by mass of 59:5:4 to prepare an active material. The active material was placed on a punched nickel to prepare a zinc negative electrode. A positive electrode was prepared by attaching a zinc plate and the above-described active material to a punched nickel. A single-layer anion conducting membrane was placed between these electrodes. The charge and discharge cycle was performed using a mercury electrode as a reference electrode at a charge and discharge current of 60 mA/cm.sup.2 for 10 minutes to confirm charge and discharge characteristics of the anion conducting membrane.

(35) The number of cells placed: Five cells (average)

(36) Reference electrode: Mercury electrode

(37) Electrolyte solution: 6.7 mol/L KOH aqueous solution saturated with zinc oxide

(38) <Average Particle Size of Inorganic Compound Particles>

(39) The average particle size of the particles of an inorganic compound was measured using a dispersion prepared by dispersing the particles of an inorganic compound in a below-described dispersion medium by laser diffraction (apparatus name: laser diffraction-scattering particle size distribution measuring apparatus LA-950 produced by HORIBA, Ltd., dispersion medium: 0.2% by mass sodium hexametaphosphate-containing ion exchange water). Thus, a 50% volume average particle size was determined as the volume average particle size.

(40) <Volume Average Particle Size of Polymer Aqueous Dispersion>

(41) The volume average particle size of a polymer aqueous dispersion was measured as follows: an aqueous dispersion of a polymer was diluted with distilled water, and about 10 mL of the dilution was put into a glass cell, and subjected to dynamic light scattering using a particle size distribution analyzer (trade name: NICOMP Model 380 produced by Particle Sizing Systems). Thus, a 50% volume average particle size was determined as the volume average particle size.

(42) <Glass Transition Temperature of Polymer>

(43) The glass transition temperature was measured as follows: a polymer was applied to a glass plate and dried at 120 C. for one hour to form a polymer film, and the glass transition temperature of the resulting polymer film was measured using a differential scanning calorimeter (apparatus name: thermal analyzer DSC3100S produced by BRVKER).

(44) <Area Ratio Between Particles of Compound and Components of Anion Conducting Membrane-Forming Material Other than the Compound>

(45) The area ratio was determined as follows: the anion conducting membrane was cut perpendicular to the surface of the membrane to prepare a membrane cross-section (the membrane cross-section was prepared using a 10 mm10 mm area in the short-side central portion of the anion conducting membrane), and 10000 magnified images of any five different points of the cross-section were taken using a scanning electron microscope so that the anion conducting membrane-forming material portion accounted for 70% or more of the cross-section. An area of 8 m in the thickness direction12 m in the plane direction was randomly selected in each magnified image of the cross-section, and opened in Microsoft Paint Ver. 5.1, graphic software produced by Microsoft, and further the area of the anion conducting membrane-forming material portion was extracted and converted to black-and-white. In the converted image, the area of other than the inorganic compound particles was represented by black, and the area of the inorganic compound particles was represented by white. The resulting image was analyzed using image analysis software produced by Image metrology to determine the ratio between the combined area of the inorganic compound particles and the combined area of other than the inorganic compound particles in the image. In the processing, the contrast of the black and white areas was increased to represent the particles as distinct dots.

(46) <Proportion of Voids>

(47) Similarly to the above area ratio, the area ratio was determined as follows: the anion conducting membrane was cut perpendicular to the surface of the membrane to prepare a membrane cross-section (the membrane cross-section was prepared using a 10 mm10 mm area in the short-side central portion of the anion conducting membrane), and 10000-times magnified images of any five different points of the cross-section were taken using a scanning electron microscope so that the anion conducting membrane-forming material portion accounted for 70% or more of the cross-section. An area of 8 m in the thickness direction12 m in the plane direction was randomly selected in each magnified image of the cross-section was opened in Microsoft Paint Ver. 5.1, graphic software produced by Microsoft, and further the area of the anion conducting membrane-forming material portion was extracted and converted to black-and-white. In the converted image, the area of the voids was represented by black, and the area of components was represented by white. The resulting image was analyzed using image analysis software produced by Image metrology to determine the proportion of the voids in the image. In the processing, the contrast of the black and white areas was increased to represent the voids as distinct dots.

(48) <Cross-Sectional Particle Size of Inorganic Compound Particles in Membrane>

(49) Similarly to the above area ratio, the area ratio was determined as follows: the anion conducting membrane was cut perpendicular to the surface of the membrane to prepare a membrane cross-section (the membrane cross-section was prepared using a 10 mm10 mm area in the short-side central portion of the anion conducting membrane), and 10000 magnified images of any five different points of the cross-section were taken using a scanning electron microscope so that the anion conducting membrane-forming material portion accounted for 70% or more of the cross-section. Here, the contrast was adjusted so that only the area of the particles of the inorganic compound was represented by white in the following image processing and the adjusted image was saved. An area of 8 m in the thickness direction12 m in the plane direction was randomly selected in each magnified image of the cross-section was opened in Microsoft Paint Ver. 5.1, graphic software produced by Microsoft, and further the area of the anion conducting membrane-forming material portion was extracted and converted to black-and-white. In the converted image, the area of the inorganic compound particles was represented by white. The resulting image was analyzed using image analysis software produced by Image metrology to determine the particle size of the inorganic compound particles from the white area in the image. In the processing, the contrast of the black and white areas was increased to represent the particles as distinct dots. One hundred particles were measured, and the resulting values were averaged to give the cross-sectional particle size. When elliptical particles were observed, the value of the major axis and the value of the minor axis were measured and averaged for 100 particles, and the resulting average values were averaged to determine the cross-sectional particle size.

(50) <Evaluation of Membrane-Forming Properties>

(51) The membrane-forming properties were evaluated as follows.

(52) 0. No membrane was formed.

(53) 1. A membrane was formed, but partly adhered to a roller and broken.

(54) 2. Breakage and damage were less, but much unevenness was observed.

(55) 3. A strong membrane was formed.

Preparation Example of (Meth)Acrylic Based Polymer

Preparation Example 1

(56) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 64 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion was prepared from 26 parts by mass of deionized water, 4 parts by mass of a 10% aqueous solution of sodium dodecylbenzenesulfonate, 1.5 parts by mass of 1,6-hexanediol dimethacrylate, 46.5 parts by mass of methyl methacrylate, 50 parts by mass of dodecyl methacrylate, and 2 parts by mass of acrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion was added to the flask, the contents were heated to 80 C. under stirring while nitrogen gas was gently blown into the flask, and 2 parts by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the resulting pre-emulsion (123.5 parts by mass), 6 parts by mass of a 5% aqueous solution of ammonium persulfate, and 6 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise to the flask over two hours. After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 48.2%, a pH of 7.8, and a volume average particle size of 190 nm.

Preparation Example 2

(57) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 64 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion was prepared from 26 parts by mass of deionized water, 4 parts by mass of a 10% aqueous solution of sodium dodecylbenzenesulfonate, 54 parts by mass of methyl methacrylate, 44 parts by mass of dodecyl methacrylate, and 2 parts by mass of acrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion was added to the flask, the contents were heated to 80 C. under stirring while nitrogen gas was gently blown into the flask, and 2 parts by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the resulting pre-emulsion (123.5 parts by mass), 6 parts by mass of a 5% aqueous solution of ammonium persulfate, and 6 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise to the flask over two hours. After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 47.8%, a pH of 7.6, and a volume average particle size of 175 nm was obtained.

Preparation Example 3

(58) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 63 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion was prepared from 21 parts by mass of deionized water, 10 parts by mass of a 25% aqueous solution of HITENOL LA-10, 1.5 parts by mass of 1,6-hexanediol dimethacrylate, 21 parts by mass of methyl methacrylate, 76 parts by mass of 2-ethylhexyl methacrylate, and 1.5 parts by mass of acrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion was added to the flask, the contents were heated to 80 C. under stirring while nitrogen gas was gently blown into the flask, and 2 parts by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the resulting pre-emulsion (124.5 parts by mass), 6 parts by mass of a 5% aqueous solution of ammonium persulfate, and 6 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise to the flask over two hours. After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 47.7%, a pH of 7.9, and a volume average particle size of 200 nm was obtained.

Preparation Example 4

(59) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 64 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion was prepared from 26 parts by mass of deionized water, 4 parts by mass of a 10% aqueous solution of sodium dodecylbenzenesulfonate, 1.5 parts by mass of 1,6-hexanediol dimethacrylate, 56.5 parts by mass of methyl methacrylate, 41 parts by mass of dodecyl methacrylate, 1 part by mass of methacrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion was added to the flask, the contents were heated to 80 C. under stirring while nitrogen gas was gently blown into the flask, and 2 parts by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the resulting pre-emulsion (123.5 parts by mass), 6 parts by mass of a 5% aqueous solution of ammonium persulfate, and 6 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise to the flask over two hours. After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 48.0%, a pH of 8.1, and a volume average particle size of 220 nm was obtained.

Preparation Example 5

(60) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 59 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion (1) was prepared from 10.5 parts by mass of deionized water, 6 parts by mass of a 25% aqueous solution of HITENOL NF-08 (produced by Dai-Ichi Kogyo Seiyaku Co., Ltd.), 18 parts by mass of 2-ethylhexyl acrylate, 31 parts by mass of n-butyl methacrylate, and 1 part by mass of acrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion (1) was added to the flask, the contents were heated to 80 C. while nitrogen gas was gently blown, and 1 part by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the pre-emulsion (1) (60 parts by mass), 3 parts by mass of 5% ammonium persulfate, and 3 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise over two hours.

(61) After the dropwise addition, the temperature was further maintained at 80 C. for one hour. Subsequently, a pre-emulsion (2) containing 10.5 parts by mass of deionized water, 6 parts by mass of a 25% aqueous solution of HITENOL NF-08 (produced by Dai-Ichi Kogyo Seiyaku Co., Ltd.), 18 parts by mass of 2-ethylhexyl acrylate, 30 parts by mass of n-butyl methacrylate, and 2 parts by mass of acrylic acid; 3 parts by mass of a 5% aqueous solution of ammonium persulfate; and 3 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise over two hours.

(62) After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 48.1%, a pH of 7.6, and a volume average particle size of 180 nm was obtained.

Preparation Example 6

(63) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 64 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion was prepared from 21 parts by mass of deionized water, 10 parts by mass of a 25% aqueous solution of HITENOL LA-10, 1.5 parts by mass of 1,6-hexanediol dimethacrylate, 53 parts by mass of methyl methacrylate, 44 parts by mass of 2-ethylhexyl acrylate, and 1.5 parts by mass of acrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion was added to the flask, the contents were heated to 80 C. under stirring while nitrogen gas was gently blown into the flask, and 2 parts by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the resulting pre-emulsion (124.5 parts by mass), 6 parts by mass of a 5% aqueous solution of ammonium persulfate, and 6 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise to the flask over two hours. After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 48.3%, a pH of 7.8, and a volume average particle size of 190 nm was obtained.

Preparation Example 7

(64) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 59 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion (1) was prepared from 10.5 parts by mass of deionized water, 6 parts by mass of a 25% aqueous solution of HITENOL NF-08 (produced by Dai-Ichi Kogyo Seiyaku Co., Ltd.), 1 part by mass of 1,6-hexanediol dimethacrylate, 10 parts by mass of methyl methacrylate, 23 parts by mass of dodecyl methacrylate, 5 parts by mass of styrene, 10 parts by mass of n-butyl methacrylate, and 1 part by mass of acrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion (1) was added to the flask, the contents were heated to 80 C. while nitrogen gas was gently blown, and 1 part by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the pre-emulsion (1) (60 parts by mass), 3 parts by mass of 5% ammonium persulfate, and 3 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise over two hours.

(65) After the dropwise addition, the temperature was further maintained at 80 C. for one hour. Subsequently, a pre-emulsion (2) containing 10.5 parts by mass of deionized water, 6 parts by mass of a 25% aqueous solution of HITENOL NF-08 (produced by Dai-Ichi Kogyo Seiyaku Co., Ltd.), 0.5 parts by mass of 1,6-hexanediol dimethacrylate, 10 parts by mass of methyl methacrylate, 23 parts by mass of dodecyl methacrylate, 15 parts by mass of styrene, 1 part by mass of itaconic acid, and 0.5 parts by mass of acrylic acid; 3 parts by mass of a 5% aqueous solution of ammonium persulfate; and 3 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise over two hours.

(66) After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 48.1%, a pH of 7.7, and a volume average particle size of 185 nm was obtained.

Preparation Example 8

(67) A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 64 parts by mass of deionized water. Separately, in the dropping funnel, a pre-emulsion was prepared from 26 parts by mass of deionized water, 4 parts by mass of a 10% aqueous solution of sodium dodecylbenzenesulfonate, 24 parts by mass of methyl methacrylate, 43.5 parts by mass of dodecyl methacrylate, 30 parts by mass of styrene, 1 part by mass of itaconic acid, and 1.5 parts by mass of acrylic acid. Next, a 6.5-part by mass portion of the resulting pre-emulsion was added to the flask, the contents were heated to 80 C. under stirring while nitrogen gas was gently blown into the flask, and 2 parts by mass of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Subsequently, the rest of the resulting pre-emulsion (123.5 parts by mass), 6 parts by mass of a 5% aqueous solution of ammonium persulfate, and 6 parts by mass of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly added dropwise to the flask over two hours. After the dropwise addition, the temperature was further maintained at 80 C. for two hours, and 25% ammonia water was added so that the pH reached about 8. Thereafter, the reaction solution was cooled to room temperature. Thus, an aqueous dispersion of a (meth)acrylic based copolymer having a nonvolatile content of 48.2%, a pH of 7.6, and a volume average particle size of 185 nm was obtained.

1. Examples of the First Aspect of the Invention

Example 1-1

(68) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: POLYFLON D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 100:100:5:3:15. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 3 based on the above criteria.

(69) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.3 N, a density () of 1.54 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 228,690.

(70) Further, the resulting anion conducting membrane had a liquid absorption rate of 18% and a degree of swelling of 9%.

(71) The cross-section of the resulting anion conducting membrane observed with a scanning electron microscope was shown in FIG. 1. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 54/46, and the proportion of the voids was 0.00%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.36 m.

(72) The resulting anion conducting membrane had a resistance (R) of 0.23, and achieved 310 cycles of charge and discharge in charge-discharge evaluation. FIG. 3 shows the results of the charge-discharge evaluation.

Example 1-2

(73) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 100:100:5:3:15. The kneaded mixture was roll-pressed to prepare a 300-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 3 based on the above criteria.

(74) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 4.3 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 300 m. The X value determined from these values was 97,395.

(75) Further, the resulting anion conducting membrane had a liquid absorption rate of 20% and a degree of swelling of 11%.

(76) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.2% or less. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.39 m.

(77) The resulting anion conducting membrane had a resistance (R) of 0.64, and achieved 700 cycles of charge and discharge in charge-discharge evaluation.

Example 1-3

(78) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 65:135:5:3:15. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 1 based on the above criteria.

(79) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.1 N, a density () of 1.35 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 188,325.

(80) Further, the resulting anion conducting membrane had a liquid absorption rate of 17% and a degree of swelling of 11%.

(81) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 33/67, and the proportion of the voids was 0%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.42 m.

(82) The resulting anion conducting membrane had a resistance (R) of 0.22, and achieved 250 cycles of charge and discharge in charge-discharge evaluation.

Example 1-4

(83) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 135:65:5:3:15. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 1 based on the above criteria.

(84) The anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.7 N, a density () of 1.68 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 204,120.

(85) Further, the resulting anion conducting membrane had a liquid absorption rate of 15% and a degree of swelling of 9%.

(86) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 69/31, and the proportion of the voids was 0.5%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.30 m.

(87) The resulting anion conducting membrane had a resistance (R) of 0.20, and achieved 260 cycles of charge and discharge in charge-discharge evaluation.

Example 1-5

(88) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD102A, produced by JSR Corporation, Tg=5 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 100:100:5:3:15. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 3 based on the above criteria.

(89) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.7 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 183,465.

(90) Further, the resulting anion conducting membrane had a liquid absorption rate of 16% and a degree of swelling of 9%.

(91) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 52/48, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.34 m.

(92) The resulting anion conducting membrane had a resistance (R) of 0.23, and achieved 300 cycles of charge and discharge in charge-discharge evaluation.

Example 1-6

(93) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD104A produced by JSR Corporation, Tg=7 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 100:100:5:3:20. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 2 based on the above criteria.

(94) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.8 N, a density () of 1.49 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 187,740.

(95) Further, the resulting anion conducting membrane had a liquid absorption rate of 15% and a degree of swelling of 9%.

(96) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 53/47, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(97) The resulting anion conducting membrane had a resistance (R) of 0.2, and achieved 300 cycles of charge and discharge in charge-discharge evaluation.

Example 1-7

(98) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m) and an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%) were kneaded with a kneader at a ratio by mass of 100:100. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 1 based on the above criteria.

(99) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.2 N, a density () of 1.53 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 220,320.

(100) Further, the resulting anion conducting membrane had a liquid absorption rate of 18% and a degree of swelling of 11%.

(101) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 54/46, and the proportion of the voids was 0.2% relative to the total area of the cross-section of the membrane. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.39 m.

(102) The resulting anion conducting membrane had a resistance (R) of 0.25, and achieved 290 cycles of charge and discharge in charge-discharge evaluation.

Example 1-8

(103) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD1002 produced by JSR Corporation, Tg=20 C., solid content: 50%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 100:100:5:3:15. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 1 based on the above criteria.

(104) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.1 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 212,040.

(105) Further, the resulting anion conducting membrane had a liquid absorption rate of 18% and a degree of swelling of 11%.

(106) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 52/48, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.39 m.

(107) The resulting anion conducting membrane had a resistance (R) of 0.20, and achieved 300 cycles of charge and discharge in charge-discharge evaluation.

Example 1-9

(108) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 50%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:5:15. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 1 based on the above criteria.

(109) Further, the resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.0 N, a density () of 1.53 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 206,550.

(110) The resulting anion conducting membrane had a liquid absorption rate of 17% and a degree of swelling of 9%.

(111) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.5%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.42 m.

(112) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 280 cycles of charge and discharge in charge-discharge evaluation.

Example 1-10

(113) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 50%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 100:100:3:15. The kneaded mixture was roll-pressed to prepare a 100-m-thick anion conducting membrane. The membrane-forming properties were evaluated as 2 based on the above criteria.

(114) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.7 N, a density () of 1.53 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 185,895.

(115) Further, the resulting anion conducting membrane had a liquid absorption rate of 18% and a degree of swelling of 10%.

(116) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 51/49, and the proportion of the voids was 0.7%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.40 m.

(117) The resulting anion conducting membrane had a resistance (R) of 0.22, and achieved 270 cycles of charge and discharge in charge-discharge evaluation.

Example 1-11

(118) An amount of 100 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 100 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1, 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 10 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 100 m, and heated at 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 3 based on the above criteria.

(119) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 1.9 N, a density () of 1.50 g/cm.sup.3, and a thickness (L) of 99 m. The X value determined from these values was 129,545.

(120) Further, the resulting anion conducting membrane had a liquid absorption rate of 11% and a degree of swelling of 4%.

(121) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 54/46, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(122) The resulting anion conducting membrane had a resistance (R) of 0.22, and achieved 400 cycles in charge-discharge evaluation.

Example 1-12

(123) An anion conducting membrane was obtained in the same manner as in Example 1-11, except that an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 2 was used instead of the aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1 in Example 1-11. The membrane-forming properties were evaluated as 2 based on the above criteria.

(124) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.7 N, a density () of 1.53 g/cm.sup.3, and a thickness (L) of 102 m. The X value determined from these values was 182,250.

(125) Further, the resulting anion conducting membrane had a liquid absorption rate of 13% and a degree of swelling of 3%.

(126) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.34 m.

(127) The resulting anion conducting membrane had a resistance (R) of 0.22, and achieved 400 cycles in charge-discharge evaluation.

Example 1-13

(128) An anion conducting membrane was obtained in the same manner as in Example 1-11, except that an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 3 was used instead of the aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1 in Example 1-11. The membrane-forming properties were evaluated as 2 based on the above criteria.

(129) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.5 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 103 m. The X value determined from these values was 164,927.

(130) Further, the resulting anion conducting membrane had a liquid absorption rate of 13% and a degree of swelling of 4%.

(131) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 56/44, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.34 m.

(132) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 350 cycles in charge-discharge evaluation.

Example 1-14

(133) An anion conducting membrane was obtained in the same manner as in Example 1-11, except that an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 4 was used instead of the aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1 in Example 1-11. The membrane-forming properties were evaluated as 2 based on the above criteria.

(134) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 1.7 N, a density () of 1.50 g/cm.sup.3, and a thickness (L) of 98 m. The X value determined from these values was 117,092.

(135) Further, the resulting anion conducting membrane had a liquid absorption rate of 12% and a degree of swelling of 3%.

(136) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 56/44, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.34 m.

(137) The resulting anion conducting membrane had a resistance (R) of 0.23, and achieved 360 cycles in charge-discharge evaluation.

Example 1-15

(138) An anion conducting membrane was obtained in the same manner as in Example 1-11, except that an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 5 was used instead of the aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1 in Example 1-11. The membrane-forming properties were evaluated as 1 based on the above criteria.

(139) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 1.9 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 99 m. The X value determined from these values was 131,273.

(140) Further, the resulting anion conducting membrane had a liquid absorption rate of 13% and a degree of swelling of 5%.

(141) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(142) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 330 cycles in charge-discharge evaluation.

Example 1-16

(143) An anion conducting membrane was obtained in the same manner as in Example 1-11, except that an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 6 was used instead of the aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1 in Example 1-11. The membrane-forming properties were evaluated as 3 based on the above criteria.

(144) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 1.9 N, a density () of 1.5 g/cm.sup.3, and a thickness (L) of 103 m. The X value determined from these values was 124,515.

(145) Further, the resulting anion conducting membrane had a liquid absorption rate of 13% and a degree of swelling of 5%.

(146) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.33 m.

(147) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 330 cycles in charge-discharge evaluation.

Example 1-17

(148) An anion conducting membrane was obtained in the same manner as in Example 1-11, except that an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 7 was used instead of the aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1 in Example 1-11. The membrane-forming properties were evaluated as 2 based on the above criteria.

(149) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.8 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 101 m. The X value determined from these values was 188,376.

(150) Further, the resulting anion conducting membrane had a liquid absorption rate of 12% and a degree of swelling of 3%.

(151) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.35 m.

(152) The resulting anion conducting membrane had a resistance (R) of 0.23, and achieved 380 cycles in charge-discharge evaluation.

Example 1-18

(153) An anion conducting membrane was obtained in the same manner as in Example 1-11, except that an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 8 was used instead of the aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1 in Example 1-11. The membrane-forming properties were evaluated as 1 based on the above criteria.

(154) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.5 N, a density () of 1.49 g/cm.sup.3, and a thickness (L) of 99 m. The X value determined from these values was 169,318.

(155) Further, the resulting anion conducting membrane had a liquid absorption rate of 16% and a degree of swelling of 7%.

(156) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.38 m.

(157) The resulting anion conducting membrane had a resistance (R) of 0.20, and achieved 400 cycles in charge-discharge evaluation.

Example 1-19

(158) An amount of 135 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 65 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1, 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 15 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 100 m, and heated 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 1 based on the above criteria.

(159) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 1.5 N, a density () of 1.67 g/cm.sup.3, and a thickness (L) of 103 m. The X value determined from these values was 109,442.

(160) Further, the resulting anion conducting membrane had a liquid absorption rate of 11% and a degree of swelling of 5%.

(161) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 65/35, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(162) The resulting anion conducting membrane had a resistance (R) of 0.20, and achieved 400 cycles in charge-discharge evaluation.

Example 1-20

(163) An amount of 65 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 135 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1, 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 2 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 100 m, and heated 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 1 based on the above criteria.

(164) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.2 N, a density () of 1.34 g/cm.sup.3, and a thickness (L) of 102 m. The X value determined from these values was 130,059.

(165) Further, the resulting anion conducting membrane had a liquid absorption rate of 13% and a degree of swelling of 4%.

(166) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 34/66, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.38 m.

(167) The resulting anion conducting membrane had a resistance (R) of 0.20, and achieved 360 cycles in charge-discharge evaluation.

Example 1-21

(168) An amount of 100 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 100 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 2, 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 10 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 50 m, and heated 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 2 based on the above criteria.

(169) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 1.8 N, a density () of 1.54 g/cm.sup.3, and a thickness (L) of 52 m. The X value determined from these values was 239,885.

(170) Further, the resulting anion conducting membrane had a liquid absorption rate of 13% and a degree of swelling of 4%.

(171) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.34 m.

(172) The resulting anion conducting membrane had a resistance (R) of 0.10, and achieved 380 cycles in charge-discharge evaluation.

Example 1-22

(173) An amount of 100 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 100 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 2, 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 10 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 100 m, and heated 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 2 based on the above criteria.

(174) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.2 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 153 m. The X value determined from these values was 143,059.

(175) Further, the resulting anion conducting membrane had a liquid absorption rate of 14% and a degree of swelling of 3%.

(176) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.35 m.

(177) The resulting anion conducting membrane had a resistance (R) of 0.31, and achieved 410 cycles in charge-discharge evaluation.

Example 1-23

(178) An amount of 100 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 100 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 3, 3 parts by mass of methyl cellulose (trade name: SM1500 produced by Shin-Etsu Chemical Co., Ltd.), and 10 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 100 m, and heated 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 2 based on the above criteria.

(179) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.2 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 150,480.

(180) Further, the resulting anion conducting membrane had a liquid absorption rate of 11% and a degree of swelling of 3%.

(181) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 56/44, and the proportion of the voids was 0.3%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.34 m.

(182) The resulting anion conducting membrane had a resistance (R) of 0.26, and achieved 400 cycles in charge-discharge evaluation.

Example 1-24

(183) An amount of 100 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 100 parts by mass of an aqueous dispersion of an acrylonitrile-butadiene based copolymer (product name: NA-13, produced by A&L, solid content: 47%), 5 parts by mass of an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 15 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed. Thus, a 100-m-thick anion conducting membrane was obtained. The membrane-forming properties were evaluated as 1 based on the above criteria.

(184) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.6 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 177,840.

(185) Further, the resulting anion conducting membrane had a liquid absorption rate of 19% and a degree of swelling of 11%.

(186) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 52/48, and the proportion of the voids was 0.3%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.36 m.

(187) The resulting anion conducting membrane had a resistance (R) of 0.22, and achieved 340 cycles in charge-discharge evaluation.

Example 1-25

(188) An anion conducting membrane was obtained in the same manner as in Example 1-13, except that 5 parts by mass of a polyacrylic acid salt (trade name: AQUALIC DL522 produced by Nippon Shokubai Co., Ltd.) was used instead of 3 parts by mass of the carboxymethylcellulose as in Example 1-13 and the amount of the pure water was changed from 10 parts by mass as in Example 1-13 to 5 parts by mass. The membrane-forming properties were evaluated as 2 based on the above criteria.

(189) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.1 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 142,695.

(190) Further, the resulting anion conducting membrane had a liquid absorption rate of 18% and a degree of swelling of 12%.

(191) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 54/46, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.34 m.

(192) The resulting anion conducting membrane had a resistance (R) of 0.19, and achieved 350 cycles in charge-discharge evaluation.

Example 1-26

(193) An amount of 50 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 50 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1, 1 part by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 60 parts by mass of pure water were kneaded with a homogenizing disperser to prepare a uniform aqueous slurry of the anion conducting membrane-forming material. The resulting aqueous slurry was applied with an applicator to the silicone-treated surface of a polyethylene terephthalate (PET) film (release film) in which one surface was treated with silicone, and dried at 120 C. for 30 minutes. Thereafter, the resulting coating of the anion conducting membrane-forming material was peeled from the release film. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 3 based on the above criteria.

(194) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.5 N, a density () of 1.53 g/cm.sup.3, and a thickness (L) of 98 m. The X value determined from these values was 175,638.

(195) Further, the resulting anion conducting membrane had a liquid absorption rate of 12% and a degree of swelling of 5%.

(196) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 52/48, and the proportion of the voids was 0% relative to the total area of the cross-section of the membrane. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.35 m.

(197) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 420 cycles in charge-discharge evaluation.

Example 1-27

(198) An anion conducting membrane was obtained in the same manner as in Example 1-26, except that an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 50%) was used instead of the aqueous dispersion of the (meth)acrylic based copolymer in Example 1-26. The membrane-forming properties were evaluated as 3 based on the above criteria.

(199) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.6 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 177,840.

(200) Further, the resulting anion conducting membrane had a liquid absorption rate of 16% and a degree of swelling of 9.5%.

(201) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 52/48, and the proportion of the voids was 0% relative to the total area of the cross-section of the membrane. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.39 m.

(202) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 320 cycles in charge-discharge evaluation.

Comparative Example 1-1

(203) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), and pure water were kneaded with a kneader at a ratio by mass of 100:120:50. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The cross-section of the resulting membrane observed with a scanning electron microscope was shown in FIG. 2. The membrane-forming properties were evaluated as 3 based on the above criteria.

(204) The resulting anion conducting membrane had an air permeance (T) of 1,000 s, a piercing strength (F) of 0.6 N, a density () of 1.27 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 38.

(205) Further, the resulting anion conducting membrane had a liquid absorption rate of 25% and a degree of swelling of 11%. Further, the proportion of the voids was 4.5%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.40 m.

(206) The resulting anion conducting membrane had a resistance (R) of 0.19. In charge-discharge evaluation as in Example 1-1, a short circuit occurred between the positive electrode and the negative electrode due to dendrite growth in the 85th cycle of charge and discharge. FIG. 3 shows the results of the charge-discharge evaluation.

Comparative Example 1-2

(207) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), and pure water were kneaded with a kneader at a ratio by mass of 100:120:50. The kneaded mixture was roll-pressed. Thus, a 300-m-thick anion conducting membrane was obtained. The membrane-forming properties were evaluated as 3 based on the above criteria.

(208) The resulting anion conducting membrane had an air permeance (T) of 1,600 s, a piercing strength (F) of 1.3 N, a density () of 1.29 g/cm.sup.3, and a thickness (L) of 300 m. The X value determined from these values was 72.

(209) Further, the resulting anion conducting membrane had a liquid absorption rate of 23% and a degree of swelling of 15%. Further, the proportion of the voids was 5.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.39 m.

(210) The resulting anion conducting membrane had a resistance (R) of 0.57. In charge-discharge evaluation as in Example 1-1, a short circuit occurred between the positive electrode and the negative electrode due to dendrite growth in the 165th cycle of charge and discharge. FIG. 3 shows the results of the charge-discharge evaluation.

Comparative Example 1-3

(211) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 150:50:5:3:30. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The membrane-forming properties were evaluated as 1 based on the above criteria.

(212) The resulting anion conducting membrane had an air permeance (T) of 3,800 s, a piercing strength (F) of 1.4 N, a density () of 1.59 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 1607.

(213) The resulting anion conducting membrane had a liquid absorption rate of 17% and a degree of swelling of 11%.

(214) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 74/26, and the proportion of the voids was 1.4%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.38 m.

(215) The resulting anion conducting membrane had a resistance (R) of 0.24, and in charge-discharge evaluation, a short circuit occurred between the positive electrode and the negative electrode due to dendrite growth in the 120th cycle of charge and discharge.

Comparative Example 1-4

(216) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and pure water were kneaded with a kneader at a ratio by mass of 50:150:5:3:15. The resulting kneaded mixture was highly fluid, and could not be formed into a membrane. The membrane-forming properties were evaluated as 0 based on the above criteria.

Comparative Example 1-5

(217) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m) and a 50% polyolefin dispersion (product name: CHEMIPEARL, Mitsui Chemicals, Inc.) were kneaded with a kneader at a ratio by mass of 100:100. These materials could not be sufficiently bonded to each other, and were less likely to be formed into a membrane. The membrane-forming properties were evaluated as 0 based on the above criteria.

Comparative Example 1-6

(218) An amount of 145 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 55 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1, 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 10 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 100 m, and heated 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 2 based on the above criteria.

(219) The resulting anion conducting membrane had an air permeance (T) of 4,000 s, a piercing strength (F) of 1.9 N, a density () of 1.67 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 2538.

(220) Further, the resulting anion conducting membrane had a liquid absorption rate of 16% and a degree of swelling of 11%.

(221) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 74/26, and the proportion of the voids was 1.3%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(222) The resulting anion conducting membrane had a resistance (R) of 0.18, and achieved 120 cycles in charge-discharge evaluation.

Comparative Example 1-7

(223) An amount of 55 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 145 parts by mass of an aqueous dispersion of the (meth)acrylic based copolymer obtained in Preparation Example 1, 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 10 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed to a thickness of 100 m, and heated 120 C. for 10 minutes. Thus, an anion conducting membrane was obtained. The membrane-forming properties were evaluated as 1 based on the above criteria.

(224) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 2.3 N, a density () of 1.33 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 137,655.

(225) Further, the resulting anion conducting membrane had a liquid absorption rate of 15% and a degree of swelling of 11%.

(226) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 27/73, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(227) The resulting anion conducting membrane had a resistance (R) of 0.26, and achieved 110 cycles in charge-discharge evaluation.

Example 1-28

(228) An aqueous slurry of an anion conducting membrane-forming material was obtained in the same manner as in Example 1-27. The resulting aqueous slurry was applied with an applicator to a non-woven fabric (trade name: H-8007, produced by Japan Vilene Company, Ltd.) in an amount of 1 g/cm.sup.2, and dried at 120 C. for 30 minutes. Thus, the non-woven fabric and the anion conducting membrane thereon were integrated to prepare an anion conducting membrane laminate.

(229) The resulting anion conducting membrane laminate had an air permeance (T) of 30,000 s, a piercing strength (F) of 4.7 N, a density () of 1.23 g/cm.sup.3, and a thickness (L) of 185 m. The X value determined from these values was 140,619.

(230) The resulting anion conducting membrane laminate had a liquid absorption rate of 11% and a degree of swelling of 0.8%.

(231) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the anion conducting membrane portion of the resulting anion conducting membrane laminate was 53/47, and the proportion of the voids was 0% relative to the total area of the cross-section of the membrane. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(232) The resulting anion conducting membrane laminate had a resistance (R) of 0.14, and when the resulting anion conducting membrane laminate was used as a separator in charge-discharge evaluation, 360 cycles were achieved.

Example 1-29

(233) The anion conducting membrane obtained in Example 1-1 was placed on a non-woven fabric (trade name: H-8007 produced by Japan Vilene Company, Ltd.), and they were bonded to each other with a roll-type laminator. Thus, the non-woven fabric and the anion conducting membrane thereon were integrated to prepare an anion conducting membrane laminate. When the resulting anion conducting membrane laminate was used as a separator in charge-discharge evaluation, 340 cycles of charge and discharge were achieved.

Example 1-30

(234) The resulting anion conducting membrane obtained in Example 1-22 was placed on a non-woven fabric (trade name: H-8007 produced by Japan Vilene Company, Ltd.), and they were bonded to each other with a roll-type laminator. Thus, the non-woven fabric and the anion conducting membrane thereon were integrated to prepare an anion conducting membrane laminate. When the resulting anion conducting membrane laminate was used as a separator in charge-discharge evaluation, 450 cycles were achieved.

(235) As described above, cells having a longer life and suitable for long-term use were obtained by preparing an anion conducting membrane having the ratio of the combined area of the particles of the inorganic compound to the combined area of the other components of 70/30 to 30/70 using an anion conducting membrane-forming material containing a conjugated diene based polymer and/or a (meth)acrylic based polymer and particles of an inorganic compound such as hydrotalcite, and then forming a cell using the resulting anion conducting membrane.

2. Examples of the Second Aspect of the Invention Example 2-1

(236) An amount of 100 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 35 parts by mass of an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD-2001 produced by JSR Corporation, solid content: 48%), 5 parts by mass of an aqueous dispersion of PTFE (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), 3 parts by mass of carboxymethylcellulose (trade name: DAICEL 1380 produced by Daicel FineChem Ltd.), and 28 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed. Thus, a 100-m-thick anion conducting membrane was obtained.

(237) The resulting anion conducting membrane had an air permeance (T) of 3,500 s, a piercing strength (F) of 0.7 N, a density () of 1.28 g/cm.sup.3, and a thickness (L) of 102 m. The X value determined from these values was 538.

(238) Further, the resulting anion conducting membrane had a liquid absorption rate of 10% and a degree of swelling of 0.6%.

(239) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the anion conducting membrane portion of the resulting anion conducting membrane was 69/31, and the proportion of the voids was 4.8% relative to the total area of the cross-section of the membrane. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.39 m.

(240) The resulting anion conducting membrane had a resistance (R) of 0.19, and when the resulting anion conducting membrane was used as a separator in charge-discharge evaluation, 305 cycles were achieved.

Example 2-2

(241) An amount of 100 parts by mass of hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), 80 parts by mass of an aqueous dispersion of the (meth)acrylic based polymer obtained in Preparation Example 1, and 15 parts by mass of pure water were kneaded with a kneader to prepare a uniform kneaded mixture. The resulting kneaded mixture was roll-pressed at a roll gap of 100 m to prepare an anion conducting membrane.

(242) The resulting anion conducting membrane had an air permeance (T) of 4,300 s, a piercing strength (F) of 0.8 N, a density () of 1.24 g/cm.sup.3, and a thickness (L) of 109 m. The X value determined from these values was 841.

(243) Further, the resulting anion conducting membrane had a liquid absorption rate of 18% and a degree of swelling of 1.5%.

(244) The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the anion conducting membrane portion of the resulting anion conducting membrane was 59/41, and the proportion of the voids was 5.2% relative to the total area of the cross-section of the membrane. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.43 m.

(245) The anion conducting membrane had a resistance (R) of 0.20, and when the resulting anion conducting membrane was used as a separator in charge-discharge evaluation, 320 cycles were achieved.

Comparative Example 2-1

(246) A battery cell was formed using a zinc negative electrode prepared by coating punched nickel with an active material that was a mixture of zinc oxide and PTFE kneaded at a ratio by mass of 96:4, a non-woven fabric (average thickness: 1000 m) as a separator, a nickel positive electrode as a counter electrode, and a Ag/AgO electrode as a reference electrode.

(247) The resulting anion conducting membrane had an air permeance (T) of 1 s, a piercing strength (F) of 12 N, a density () of 0.09 g/cm.sup.3, and a thickness (L) of 1000 m. The X value determined from these values was 0.00001.

Comparative Example 2-2

(248) A battery cell was formed using the same negative and positive electrodes as in Comparative Example 2-1 and an ion conducting membrane (average thickness: 25 m) formed of a single microporous membrane formed using polyolefin and having an average pore diameter of 100 nm as a separator.

(249) The resulting anion conducting membrane had an air permeance (T) of 380 s, a piercing strength (F) of 2.7 N, a density () of 0.5 g/cm.sup.3, and a thickness (L) of 25 m. The X value determined from these values was 39.

Comparative Example 2-3

(250) Hydrotalcite as an inorganic compound and a PTFE dispersion as a polymer (trade name: POLYFLON D-210 produced by Daikin Industries, Ltd.) were kneaded at a ratio by mass of 4:6 at 30 C. for three minutes to prepare a 50-m-thick ion conducting membrane. A battery cell was formed using the same negative and positive electrodes as in Comparative Example 2-1 and the ion conducting membrane as a separator.

(251) The resulting anion conducting membrane had an air permeance (T) of 1,400 s, a piercing strength (F) of 0.7 N, a density () of 1.3 g/cm.sup.3, and a thickness (L) of 50 m. The X value determined from these values was 178.

3. Examples of the Third Aspect of the Invention Example 3-1

(252) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:20. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The resulting membrane was heated 80 C. for one hour and additionally heated at 120 C. for one hour to prepare an anion conducting membrane. The membrane-forming properties were evaluated as 2 based on the above criteria.

(253) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.5 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 237,825.

(254) Further, the resulting anion conducting membrane had a liquid absorption rate of 18% and a degree of swelling of 7%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 54/46, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.38 m.

(255) The resulting anion conducting membrane had a resistance (R) of 0.23, and achieved 450 cycles in charge-discharge evaluation.

Example 3-2

(256) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:35. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The resulting membrane was heated 80 C. for one hour, and additionally heated at 160 C. for one hour to prepare an anion conducting membrane. The membrane-forming properties were evaluated as 2 based on the above criteria.

(257) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.5 N, a density () of 1.49 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 234,675.

(258) Further, the resulting anion conducting membrane had a liquid absorption rate of 12% and a degree of swelling of 8%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 53/47, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.38 m.

(259) The resulting anion conducting membrane had a resistance (R) of 0.24, and achieved 380 cycles in charge-discharge evaluation.

Example 3-3

(260) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD102A produced by JSR Corporation, Tg=5 C., solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:5. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The resulting membrane was heated 80 C. for one hour and additionally heated at 160 C. for one hour to prepare an anion conducting membrane. The membrane-forming properties were evaluated as 2 based on the above criteria.

(261) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.4 N, a density () of 1.54 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 235,620.

(262) Further, the resulting anion conducting membrane had a liquid absorption rate of 11% and a degree of swelling of 1%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.35 m.

(263) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 330 cycles in charge-discharge evaluation.

Example 3-4

(264) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: SR-152 produced by Nippon A&L Inc., solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:20. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The resulting membrane was heated 80 C. for one hour and additionally heated at 120 C. for one hour to prepare an anion conducting membrane. The membrane-forming properties were evaluated as 1 based on the above criteria.

(265) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.2 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 218,880.

(266) Further, the resulting anion conducting membrane had a liquid absorption rate of 4% and a degree of swelling of 5%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 54/46, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.35 m.

(267) The resulting anion conducting membrane had a resistance (R) of 0.23, and achieved 305 cycles in charge-discharge evaluation.

Example 3-5

(268) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:50:5. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The resulting membrane was heated 80 C. for 12 hours to prepare an anion conducting membrane. The membrane-forming properties were evaluated as 3 based on the above criteria.

(269) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.4 N, a density () of 1.52 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 232,560.

(270) Further, the resulting anion conducting membrane had a liquid absorption rate of 8% and a degree of swelling of 6%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.35 m.

(271) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 320 cycles in charge-discharge evaluation.

Example 3-6

(272) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: SR-152 produced by NIPPON A&L INC., solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:20. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The resulting membrane was heated 80 C. for one hour to prepare an anion conducting membrane. The membrane-forming properties were evaluated as 2 based on the above criteria.

(273) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.1 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 210,645.

(274) Further, the resulting anion conducting membrane had a liquid absorption rate of 19% and a degree of swelling of 8%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 55/45, and the proportion of the voids was 0.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.38 m.

(275) The resulting anion conducting membrane had a resistance (R) of 0.22, and achieved 315 cycles in charge-discharge evaluation.

Example 3-7

(276) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD-2001 produced by JSR Corporation, solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:20. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The resulting membrane was heated 80 C. for one hour to prepare an anion conducting membrane. The membrane-forming properties were evaluated as 2 based on the above criteria.

(277) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.3 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 224,235.

(278) Further, the resulting anion conducting membrane had a liquid absorption rate of 21% and a degree of swelling of 9%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 53/47, and the proportion of the voids was 0.1%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.36 m.

(279) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 310 cycles in charge-discharge evaluation.

Example 3-8

(280) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of a styrene-butadiene based copolymer (product name: TRD2001 produced by JSR Corporation, Tg=2 C., solid content: 48%), and pure water were kneaded with a kneader at a ratio by mass of 100:100:35. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The membrane-forming properties were evaluated as 1 based on the above criteria.

(281) The resulting anion conducting membrane had an air permeance (T) of 30,000 s, a piercing strength (F) of 3.1 N, a density () of 1.51 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 210,645.

(282) Further, the resulting anion conducting membrane had a liquid absorption rate of 28% and a degree of swelling of 31%. The ratio of the combined area of the hydrotalcite particles to the combined area of the other components in the cross-section of the resulting anion conducting membrane was 53/47, and the proportion of the voids was 0.2% or less. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.37 m.

(283) The resulting anion conducting membrane had a resistance (R) of 0.21, and achieved 240 cycles in charge-discharge evaluation.

Comparative Example 3-1

(284) Hydrotalcite (trade name: DHT-6 produced by Kyowa Chemical Industry Co., Ltd., average particle size: 0.20 m), an aqueous dispersion of polytetrafluoroethylene (trade name: D210C produced by Daikin Industries, Ltd., solid content: 60%), and pure water were kneaded with a kneader at a ratio by mass of 100:120:50. The kneaded mixture was roll-pressed. Thus, a 100-m thick membrane was obtained. The membrane-forming properties were evaluated as 3 based on the above criteria.

(285) The resulting anion conducting membrane had an air permeance (T) of 1,500 s, a piercing strength (F) of 0.7 N, a density () of 1.3 g/cm.sup.3, and a thickness (L) of 100 m. The X value determined from these values was 102.

(286) Further, the resulting anion conducting membrane had a liquid absorption rate of 26% and a degree of swelling of 12%. In the cross-section of the resulting anion conducting membrane, only the hydrotalcite particles and voids were observed and no anion conducting membrane-forming material components other than the particles of the compound were observed. The proportion of the area of the voids was 5.2%. The hydrotalcite particles in the anion conducting membrane had a cross-sectional particle size of 0.41 m.

(287) The resulting anion conducting membrane had a resistance (R) of 0.20, and achieved 180 cycles in charge-discharge evaluation.

(288) As described above, cells having a much longer life and suitable for longer-term use were obtained by preparing an anion conducting membrane having a liquid absorption rate of 25% or less using an anion conducting membrane-forming material containing a conjugated diene based polymer and/or a (meth)acrylic based polymer and particles of an inorganic compound such as hydrotalcite, and forming a cell using the resulting anion conducting membrane.