PURPOSE: To enable electrolyte to be retained for a long period of time, and increase both the preservation performance and the liquid-leakage resistant performance of an alkaline battery, an air cell or the like by forming a separator for the battery from a non-woven mixed fabric consisting of a processed fiber treated with acrylic acid, a thermoplastic synthetic fiber and soluble PVA used as a binder fiber.

CONSTITUTION: A separator 1 is prepared from a non-woven fabric consisting of a processed fiber 12, which is formed by coating a fiber made of an acrylonitrile system polymer 10 with a surface layer 11 consisting of an acrylic acid which has carboxyl groups (-COOH) and is excellent in its electrolyte-holding ability, polypropylene used as a thermoplastic synthetic fiber 13, and a binder fiber 14 consisting of a soluble PVA. The above surface layer 11 consisting of acrylic acid, when impregnated with electrolyte, becomes a colloidal electrolyte holding layer due to the swollen acrylic acid. The above acrylic acid, since it is partially cross-linked, is insoluble in the electrolyte, shows an excellent swelling performance, can hold a large amount of the electrolyte, and can form a stable liquid-holding layer. In addition, the fiber 13 gives a flexibility to the separator 1, and prevents any break of the separator which might be caused during the assembly process of a battery.