PURPOSE: A thin resin film is placed on the gap between two sheets of ion- exchange membranes which oppose to each other at their edges so as to cover the gap and the part of the gap is pressed with heat to produce the titled ion- exchange membrane with flattened joint parts, which is useful as a diaphragm for alkali chloride electrolysis.
CONSTITUTION: Two sheets of ion-excange resin membrane preferably cation- exchange membrane of perfluorohydrocarbon are made to oppose to each other at their edges so that a small gap, preferably less than 2mm width, is left, and a thin resin film, preferably the one that has the same properties as the ion- exchange membrane to be jointed does and melts at 5W10°C lower than the membrane, is placed on the gap so as to cover it. Then, the part is pressed with a bakelite plate with nichrom wire heater built in to joint the two sheets. The thin film is preferably 10W15mm wide, 3/5W1/10 thick of the ion-exchange membrane and 1W10 times the volume of the gap.
SAJIMA YASUO
IWAMOTO JIYUNJIROU
