PRODUCTION OF IMPROVED DIAPHRAGM FOR ELECTROLYSIS

PURPOSE:To improve mechanical strength without degrading the performance of an asbestos diaphragm in a diaphragm type electrolytic cell for aq. alkali chloride solns. in the stage of producing said diaphragm by impregnating fine particles of specific synthetic resins in the asbestos diaphragm then subjecting the same to a curing treatment. CONSTITUTION:Asbestos fibers are put into a 10% NaOH soln. and are stirred, whereby asbestos slurry is prepared. On the other hand, the liquid prepd. by adding a fluooresin such as polytetrafluoroethylene to a latex prepd. by dispersing fine particles of a vinylidene fluoridehexafluoropropylene copolymer in water at 1:(0.5-5) ratio based on the above-mentioned copolymer and further mixing 2-20wt% hexamethylene diamine carbamate based on the fine granular solids in the latex is added to the asbestos slurry. This slurry is deposited on cathode wire nets and is then vaccum sucked, thereafter the slurry is dried by heating and is cured at 150 deg.C, whereby the asbestos diaphragm is produced.