Abstract: An ion exchange membrane having a structure that an ion exchange resin is filled in spaces of a porous base film, the porous base film has a structure that at least two porous olefin resin layers are laminated with a bonding strength of 100 gf/cm or more to less than 700 gf/cm and a Gurley air permeance of 500 sec/100 ml or less in terms of a 100 ?m thick film. In this ion exchange membrane, base film has high air permeability though it has a multi-layer structure that a plurality of porous resin films are bonded together, and therefore a rise in electric resistance caused by the lamination of the base sheets is effectively suppressed.

Abstract: An ion exchange membrane having a structure that an ion exchange resin is filled in spaces of a porous base film, the porous base film has a structure that at least two porous olefin resin layers are laminated with a bonding strength of 100 gf/cm or more to less than 700 gf/cm and a Gurley air permeance of 500 sec/100 ml or less in terms of a 100 ?m thick film. In this ion exchange membrane, base film has high air permeability though it has a multi-layer structure that a plurality of porous resin films are bonded together, and therefore a rise in electric resistance caused by the lamination of the base sheets is effectively suppressed.

Abstract: An ion-exchange membrane including a porous unstretched polyethylene sheet in which fine pores are piercing, the pores being filled with an ion-exchange resin. The ion-exchange membrane exhibits excellent concentration property.

Abstract: An ion-exchange membrane including a porous unstretched polyethylene sheet in which fine pores are piercing, the pores being filled with an ion-exchange resin. The ion-exchange membrane exhibits excellent concentration property.

Abstract: Disclosed is a bipolar membrane comprising a cation-exchange membrane in which a cation-exchange group present at least at its adhered surface has been ion-exchanged with a heavy metal ion, which is adhered closely to an anion-exchange membrane at a peel strength of not less than 0.2 kg f/25 mm, and having a water-splitting current efficiency of not less than 80% and a water-splitting membrane potential of not more than 2.0 V.

Abstract: Disclosed is an anion-exchange membrane prepared by subjecting a membrane composed of a resin containing a high-molecular-eight compound having haloalkyl groups chemically bound thereto to ultraviolet radiation or ionizing radiation to thereby decrease the amount of the haloalkyl groups present in its surface portion less than 0.1 micrometer deep from its surface by 10 to 95% from that of the haloalkyl groups present in the interior of the membrane, and the converting the haloalkyl groups present in the membrane into anion-exchange groups.