Process for producing an ion exchange membrane by grafting non ion-selective monomers onto a ion exchange

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The substrate in which a non-ion selective hydrophilic group or an ion exchange group is introduced is made of various hydrocarbon- or halogen-containing polymer films (the term "film" as used herein includes "sheets") or ion exchange membrane prepared by the copolymerization method or blending method.
The ion exchange membrane contemplated by this invention can be produced by grafting a monomer containing as ion exchange group to the hydrocarbon or halogen-containing polymer film, or by grafting a monomer containing a non-ion selective hydrophilic group to the ion exchange membrane of the latter type.
In the practice of this invention, the following methods can be used to produce an ion exchange membrane wherein both an ion exchange group and a non-ion selective hydrophilic group are incorporated in the substrate: (1) A monomer containing an ion exchange group (hereunder referred to as "monomer A") and/or a monomer containing a functional group capable of being converted to an ion exchange group by treatment such as hydrolysis (hereunder referred to as "monomer B") and a monomer containing a non-ion selective hydrophilic group (hereunder referred to as "monomer C") and/or a monomer having a functional group capable of being converted to a non-ion selective hydrophilic group by treatment such as hydrolysis (hereunder referred to as "monomer D") are co-grafted to a polymer film; (2) monomer A and/or monomer B are first grafted to a polymer film, and then monomer C and/or monomer D are grafted to the film; (3) monomer C and/or monomer D are first grafted to a polymer film, and then monomer A and/or monomer B are grafted to the film; and (4) monomer C and/or monomer D are grafted to an ion exchange membrane.
Hydrolysis and other treatments to convert the functional group in monomer B to an ion exchange group or to convert the functional group in monomer D to a non-ion selective hydrophilic group may be performed in the last step of each method, or after the first grafting is effected in methods (2) and (3)