Ion exchange membrane for alkali chloride electrolysis and alkali chloride electrolysis apparatus

An ion exchange membrane, comprising, in an order from one surface to the other surface:

• a layer (C);
• a layer (Sa);
• a layer (Sb-1);
• a reinforcing material;
• and
• a layer (Sb-2),
• wherein the layer (C) comprises a fluorinated polymer having at least one carboxylic acid functional group,
• each of the layer (Sa), the layer (Sb-1), and the layer (Sb-2) independently comprises a fluorinated polymer having at least one sulfonic acid functional group,
• the reinforcing material is completely disposed between the layer (Sb-1) and the layer (Sb-2) such that the reinforcing material is substantially in parallel with the layer (Sb-1) and the layer (Sb-2) and that the reinforcing material is not in contact with the layer (Sa),
• an ion exchange capacity of the layer (Sa) is lower than an ion exchange capacity of the layer (Sb-1) and an ion exchange capacity of the layer (Sb-2),
• the ion exchange capacity of the layer (Sb-1) is different from the ion exchange capacity of the layer (Sb-2),
• a ratio of a thickness of the layer (Sa) to a total thickness of the layer (Sb-1) and the layer (Sb-2) is at most 0.4, and
• a difference between an ion exchange capacity of the layer (C) and the ion exchange capacity of the layer (Sa) is at most 0.5 meq/g dry resin.