(GB2070847-B)      Open celled microporous membrane is coated on at least one surface with a uniform porous coating comprising a low hydrogen over-potential material. Prior to deposition of the coating, the microporous membrane has an electrical resistance when rendered hydrophilic of not greater than about 50 milliohms-sq.in a reduced bulk density (compared to the corresp. substrate membrane having no open-celled structure), a surface area of at least 10 sq./g and an av. pore size of 200-10000 Angstroms. The porous coating extends over virtually the whole surface of the substrate and has a uniform thickness of at least 50 Angstroms, but is insufficient to cause the electrical resistance of the coated membrane to exceed 75 milliohms-sq.in when rendered hydrophilic.    The microporous substrate is esp. of polypropylene and is prepd. by the 'dry stretch' method and the low hydrogen over-potential coating is e.g. of Ni, Fe, Co, Pt, Pd, In, Cr, Mn, Ti, or alloys of these in a total thickness of 100-750 Angstroms.    The coated microporous membranes are esp. useful as battery separators in rechargeable zinc electrode-contg. batteries, which are resistant to penetration by zinc dendrites and are capable of increasing the uniformity of current density on recharging the battery. (25pp)    (DE3107205-C)      Open-all microporous membrane has, on at least one surface, a coating having a uniformly porous layer (I) on a material having low hydrogen overvoltage and, before the deposition of layer (I), having an electrical resistance, in hydrophilized state, of not more than about 7.75 microohms/cm2, a low cubic measure w.r.t. the corresp. substrate membrane without an open-all structure, a surface of at least 10m2/g and a mean pore size of 20 - 1000 nm.    The porous layer covers a surface which itself is covered with the surface of the microporous substrate membrane, on which it is applied, and has a uniform total thickness of at least 5nm, but which is insufficient to increase the electrical resistance of the coated microporous membrane, in hydrophilic state, above 11.63 microohms/cm2.    USE -   Membrane is useful as a battery separator and reduces the penetration of the separator by zinc dendrites. (23pp)    (JP92027671-B)      Open celled microporous membrane is coated on at least one surface with a uniform porous coating comprising a low hydrogen over-potential material. Prior to deposition of the coating, the microporous membrane has an electrical resistance when rendered hydrophilic of not greater than about 50 milliohms-sq. in a reduced bulk density (compared to the corresp. substrate membrane having no open-celled structure), a surface area of at least 10 sq./g and an average pore size of 200-10000 Angstroms. The porous coating extends over virtually the whole surface of the substrate and has a uniform thickness of at least 50 Angstroms, but is insufficient to cause the electrical resistance of the coated membrane to exceed 75 milliohms-sq.in when rendered hydrophilic.    The microporous substrate is esp. of polypropylene and is prepd. by the `dry stretch' method and the low hydrogen over potential coating is e.g. of Ni, Fe, Co, Pt, Pd, In, Cr, Mn, Ti or alloys of these in a total thickness of 100-750 Angstroms. The coated microporous membranes are esp. useful as battery separators in rechargeable zinc electrode-contg. batteries, which are resistant to penetration by zinc dendrites and are capable of increasing the uniformity of current density on recharging the battery. (J56138864-A)