Abstract: To provide a diaphragm for electrolyzing alkaline water and a device for electrolyzing alkaline water, whereby at the time of electrolyzing alkaline water, it is possible to suppress the electrolysis voltage to be low even at a high current density and interlayer peeling is unlikely to occur. This diaphragm 1 for electrolyzing alkaline water comprises an ion-exchange membrane 10 which contains a polymer having sulfonic acid functional groups and which does not contain a polymer having carbonic acid functional groups, and a hydrophilic layer provided as the outermost layer on at least one side of the diaphragm, wherein the thickness of the ion-exchange membrane 10 is from 25 to 250 ?m. Or, the diaphragm 1 for electrolyzing alkaline water comprises an ion-exchange membrane 10, a reinforcing material 16 made of a woven fabric embedded in the ion-exchange membrane 10 and a hydrophilic layer provided as the outermost layer on at least one side of the diaphragm.

Abstract: To provide an ion exchange membrane for alkali chloride electrolysis which is a membrane having a high water permeability and being capable of maintaining a low electrolysis voltage while suppressing the amount of water supplied to a cathode chamber to be minimum, and which is capable of forming an aqueous alkali hydroxide solution having a high caustic alkali quality. The ion exchange membrane for alkali chloride electrolysis comprises a layer 12 made of a fluorinated polymer having carboxylic acid functional groups, and a layer 14A and a layer 14B made of a fluorinated polymer having sulfonic acid functional groups, wherein a reinforcing material 20 containing reinforcing threads 22 is disposed between the layer 14A and the layer 14B, the thickness when dried, of the layer 12 is from 9 to 28 ?m, the layer 14B includes a layer having an ion exchange capacity of from 1.3 to 2.

Abstract: To provide an ion exchange membrane for alkali chloride electrolysis whereby it is possible to make the electrolysis voltage low and the current efficiency high at the time of performing electrolysis of an alkali chloride; a method for its production; and an alkali chloride electrolysis apparatus using it. The ion exchange membrane for alkali chloride electrolysis has a layer (C) comprising a fluorinated polymer having carbonic acid functional groups, and a layer (S) comprising a fluorinated polymer having sulfonic acid functional groups; a reinforcing material containing reinforcing threads is disposed in the layer (S); and when measured after the ion exchange membrane for alkali chloride electrolysis is immersed and held in a 32 mass % sodium hydroxide aqueous solution warmed at 90° C. for 16 hours and subsequently immersed in a 32 mass % sodium hydroxide aqueous solution at 25° C.

Abstract: To provide a method capable of efficiently producing an ion exchange membrane for alkali chloride electrolysis which has high current efficiency, little variation in current efficiency and high alkaline resistance. This is a method for producing an ion exchange membrane 1 having a layer (C) 12 containing a fluorinated polymer (A) having carboxylic acid type functional groups, by immersing an ion exchange membrane precursor film having a precursor layer (C?) containing a fluorinated polymer (A?) having groups convertible to carboxylic acid type functional groups, in an aqueous alkaline solution comprising an alkali metal hydroxide, a water-soluble organic solvent and water, wherein the proportion of structural units having carboxylic acid type functional groups in the fluorinated polymer (A) is from 13.0 to 14.50 mol %; in the layer (C) 12, the value of resistivity is from 4.0×103 to 25.0×103 ?·cm, and the variation in resistivity is at most 4.

Abstract: To provide a method whereby it is possible to efficiently produce an ion exchange membrane for alkali chloride electrolysis, which has high current efficiency and high alkali resistance at the time of electrolyzing an alkali chloride.

Abstract: To provide a production method whereby an ion exchange membrane for alkali chloride electrolysis can be obtained which has high current efficiency, little variation in current efficiency and high alkaline resistance. This is a method for producing an ion exchange membrane 1 having a layer (C) 12 containing a fluorinated polymer (A) having carboxylic acid type functional groups, by immersing an ion exchange membrane precursor film having a precursor layer (C?) containing a fluorinated polymer (A?) having groups convertible to carboxylic acid type functional groups, in an aqueous alkaline solution comprising an alkali metal hydroxide, a water-soluble organic solvent and water, and converting the groups convertible to carboxylic acid type functional groups to carboxylic acid functional groups, wherein the concentration of the water-soluble organic solvent is from 1 to 60 mass % in the aqueous alkaline solution (100 mass %); the temperature of the aqueous alkaline solution is at least 40° C. and less than 80° C.

Abstract: To provide a process for producing an ion exchange membrane for electrolysis which has a low membrane resistance and which is capable of reducing the electrolysis voltage during the electrolysis, even if the membrane strength is increased, an ion exchange membrane for electrolysis, a precursor membrane of an ion exchange membrane for electrolysis, and an electrolysis apparatus.

Abstract: To provide an ion exchange membrane for alkali chloride electrolysis which has a low membrane resistance and which is capable of reducing the electrolysis voltage during the alkali chloride electrolysis, while increasing the membrane strength. An ion exchange membrane 1 for alkali chloride electrolysis wherein a reinforcing material 20 obtained by weaving with reinforcing yarns 22 and sacrificial yarns 24 is embedded in a fluoropolymer having ion exchange groups, the ion exchange membrane 1 comprises elution holes (28) formed by eluting at least a portion of a material of the sacrificial yarns 24, and in a cross section perpendicular to the length direction of the yarns, the total area (S) obtained by adding the cross-sectional area of an elution hole 28 and the cross-sectional area of a sacrificial yarn 24 remaining in the elution hole 28 is from 500 to 1,200 ?m2, and the number (n) of elution holes 28 between adjacent reinforcing yarns 22 is at least 10.

Abstract: To provide an ion exchange membrane for alkali chloride electrolysis for which membrane strength is increased while membrane resistance is reduced to reduce electrolysis voltage during alkali chloride electrolysis and which prevents peeling between layers (S) and a layer (C). The ion exchange membrane for alkali chloride electrolysis comprises a layer (C) which comprises a fluorinated polymer having carboxylic acid functional groups, at least two layers (S) which comprise a fluorinated polymer having sulfonic acid functional groups, and a reinforcing material, wherein the layers (S) include a layer (Sa) and a layer (Sb), the layer (Sa) is a layer which is adjacent to the layer (C), the layer (Sb) is a layer which is not adjacent to the layer (C), the reinforcing material is disposed in the layer (Sb) substantially in parallel to the layer (Sb) in a state not in contact with the layer (Sa), and the ion exchange capacity of the layer (Sa) is lower than the ion exchange capacity of the layer (Sb).

Abstract: To provide an ion exchange membrane for alkali chloride electrolysis which has high membrane strength and low membrane resistance, thereby capable of reducing the electrolysis voltage during alkali chloride electrolysis. In this ion exchange membrane (1) for alkali chloride electrolysis, a reinforcing material 20 formed by weaving reinforcing yarns 22 and sacrificial yarns 24 is disposed in a layer (S) 14, and layer (S) 14 has elution portions 28 formed by elution of at least portions of the sacrificial yarns 24.

Abstract: To provide an ion exchange membrane for alkali chloride electrolysis, which has low membrane resistance and which reduces the electrolysis voltage during alkali chloride electrolysis, even if the spacing between reinforcing yarns is made narrow to increase the membrane strength.

Abstract: The present invention provides a fluorinated cation exchange membrane comprising at least two layers, a first layer made of a fluoropolymer having sulfonic acid groups and a second layer made of a fluoropolymer having carboxylic acid groups on the cathode side thereof, wherein when an electrolytic soda process is conducted using the cation exchange membrane as a diaphragm between an anode compartment and a cathode compartment, the water transport number through the cation exchange membrane is at least 4.8 mol/F (F: Faraday) under operating conditions such that the brine concentration in the anode compartment is 200 g/L, the sodium hydroxide concentration in the cathode compartment is 32 mass %, the current density is 5 kA/m2, and the temperature is 90° C. The fluorinated cation exchange membrane of the present invention gives an excellent effect such that a uniform catholyte concentration can be maintained even when installed in an electrolytic cell having no special circulating means.

Abstract: The present invention provides a fluorinated cation exchange membrane comprising at least two layers, a first layer made of a fluoropolymer having sulfonic acid groups and a second layer made of a fluoropolymer having carboxylic acid groups on the cathode side thereof, wherein when an electrolytic soda process is conducted using the cation exchange membrane as a diaphragm between an anode compartment and a cathode compartment, the water transport number through the cation exchange membrane is at least 4.8 mol/F (F: Faraday) under operating conditions such that the brine concentration in the anode compartment is 200 g/L, the sodium hydroxide concentration in the cathode compartment is 32 mass %, the current density is 5 kA/m2, and the temperature is 90° C. The fluorinated cation exchange membrane of the present invention gives an excellent effect such that a uniform catholyte concentration can be maintained even when installed in an electrolytic cell having no special circulating means.