Ion exchange membrane and electrolyzer
An ion exchange membrane includes a layer S including a fluorine-containing polymer having a sulfonic acid group, a layer C including a fluorine-containing polymer having a carboxylic acid group, and a plurality of strengthening materials arranged inside the layer S and functioning as at least one of reinforcement yarn and sacrifice yarn. A and B satisfy following formulas: B ≤240 μm (1) 2.0≤ B/A ≤5.0 (2) wherein, when the ion exchange membrane is viewed from the top surface, A represents an average cross-sectional thickness of the membrane measured in pure water for a region, in which the strengthening materials do not exist, and B represents an average cross-sectional thickness of the membrane measured in pure water for a region, in which strands of the reinforcement yarn overlap with each other, and in a region, in which the reinforcement yarn overlaps with the sacrifice yarn.
1. An ion exchange membrane comprising:
a layer S comprising a fluorine-containing polymer having a sulfonic acid group;
a layer C comprising a fluorine-containing polymer having a carboxylic acid group; and
a plurality of strengthening materials arranged inside the layer S and functioning as at least one of reinforcement yarn and sacrifice yarn;
wherein A and B, both of which are defined below, satisfy following formulas (1) and (2):
B≤ 240 μm (1)
2.0≤ B/A≤ 5.0 (2)
wherein, when the ion exchange membrane is viewed from a top surface,
A represents an average cross-sectional thickness of the membrane measured in pure water for a region, in which the strengthening materials do not exist, and
B represents an average cross-sectional thickness of the membrane measured in pure water for a region, in which strands of the reinforcement yarn overlap with each other, and for a region, in which the reinforcement yarn overlaps with the sacrifice yarn.
2. The ion exchange membrane according to claim 1 , wherein A and C1 which is defined below satisfy following formula (3):
40 μm≤ A ≤C1 (3)
wherein C1 represents a maximum value of a distance between a surface of the layer S and reinforcement yarn most distant from the surface of the layer S, the distance being measured in pure water and in a direction of the thickness of the membrane in the region, in which strands of the reinforcement yarn overlap with each other.
3. The ion exchange membrane according to claim 1 , wherein
the layer S has a continuous hole therein and a plurality of opening portions on a surface thereof, and
a ratio of a total area of the opening portions to an area of the surface of the layer S is 0.4 to 15%.
4. The ion exchange membrane according to claim 1 , wherein a surface of the layer S has raised portions having a height of 20 μm or more, when viewed from a cross section.
5. The ion exchange membrane according to claim 4 , wherein an arrangement density of the raised portions is 20 to 1500 raised portions/cm 2 .
6. An electrolyzer comprising the ion exchange membrane according to claim 1 .
7. A method for producing the ion exchange membrane according to claim 1 .