Porous separator comprising inorganic/polymer composite fiber and method of making same

A method for forming an electrolyte permeable diaphragm on a foraminous structure for use in an electrolytic cell, which method comprises establishing an aqueous slurry by introducing to an aqueous medium as particulate material a non-isotropic organic and inorganic composite fiber comprising from about 5 percent to about 70 percent by weight organic halocarbon polymer fiber and from about 30 percent to about 95 percent by weight of very finely-divided inorganic particulates bound in said polymer fiber, and from about 10 percent to about 1,000 weight percent based on the weight of said composite fiber, of additional particulate material in mixture with said composite fiber, drawing the slurry through a foraminous substrate to deposit particulate materials thereon in the form of a diaphragm, drying the deposited diaphragm and heating same to allow the organic polymer of the composite fibers to fuse together.

A method for forming an electrolyte permeable diaphragm on a foraminous structure for use in an electrolytic cell, which method comprises establishing an aqueous slurry by introducing to an aqueous medium as particulate material a non-isotropic organic and inorganic composite fiber comprising from about 5 percent to about 70 percent by weight organic halocarbon polymer fiber and from about 30 percent to about 95 percent by weight of very finely-divided inorganic particulates bound in said polymer fiber, from about 10 to about 1,000 weight percent, based on the weight of said composite fiber, of additional particulate material in mixture with said composite fiber, and at least about 0.05 weight percent of base as well as sufficient thickening agent to provide at least about 0.5 gram per liter of thickening agent to said aqueous slurry, drawing the slurry through a foraminous substrate to deposit particulate materials thereon in the form of a diaphragm, drying the deposited diaphragm and heating same to allow the organic polymer of the composite fibers to fuse together.

A method for forming an electrolyte permeable diaphragm on a foraminous structure for use in an electrolytic cell, which method comprises (1) establishing an aqueous sIurry by introducing to an aqueous medium particulate fiber material of asbestos fiber along with non-isotropic organic and inorganic composite fiber, which composite fiber comprises, in adherent combination, from about 5 percent to about 70 percent by weight organic halocarbon polymer fiber together with from about 30 percent to about 95 percent by weight of very finely-divided inorganic particulates impacted into said polymer fiber, (2) drawing the slurry through a foraminous substrate to deposit particulate materials thereon in the form of a diaphragm, (3) drying the deposited diaphragm and (4) heating same to allow the organic polymer of the composite fibers to fuse together.

A deposited diaphragm, deposited from a slurry on a foraminous substrate, said diaphragm having non-isotropic organic and inorganic composite fibers of 5 to 70 weight organic halocarbon polymer fiber in adherent combination with from about 30 to 95 weight percent of very finely-divided inorganic particulates impacted into said fiber during fiber formation, said deposited diaphragm having a weight per unit of surface area of between about 3 and about 12 kilograms per square meter.