Alkaline battery separator and process for producing the same

A process for producing an alkaline battery separator comprising the steps of:

• substantially uniformly admixing (1) polyolefin dividable composite fibers having an average fiber length of 20 to 60 mm, said polyolefin dividable composite fibers being a combination of high-density polyethylene and polypropylene, (2) high-strength fibers having an average fiber length of 30 to 60 mm and a fiber strength of at least 7 g/denier, said high-strength fibers being polypropylene and/or ultra-high-strength polyethylene, and (3) polyolefin heat-sensitive-adhesive fibers having an average fiber length of 30 to 60 mm, said polyolefin heat-sensitive-adhesive fibers being composed of a core component of polypropylene and a sheath component of low-density polyethylene, to form a fiber web by a dry-laid method, said high-strength fibers accounting for 25 to 40 mass % with respect to a total mass of said polyolefin dividable composite fibers, said high-strength fibers and said polyolefin heat-sensitive-adhesive fibers;
• subjecting the resulting fiber web to a heat-fusing treatment and a hydro-entangling treatment, to obtain a heat-fused and hydro-entangled nonwoven fabric;
• and then, imparting a hydrophilic property to the resulting heat-fused and hydro-entangled nonwoven fabric.

A process for producing an alkaline battery separator comprising steps of:

• substantially uniformly admixing (1) polyolefin dividable composite fibers having an average fiber length of 20 to 60 mm, (2) high-strength fibers having an average fiber length of 30 to 60 mm and a fiber strength of 5 g/denier or more, and (3) polyolefin heat-sensitive-adhesive fibers having an average fiber length of 30 to 60 mm, said polyolefin heat-sensitive-adhesive fiber containing a polyolefin adhesive portion having a melting point lower that a melting point of said polyolefin dividable composite fiber and lower than a melting point of said high-strength fiber, then adding a lubricating oil thereto, and thereafter forming said fiber web by dry laid method, said high-strength fibers accounting for 20 to 45 mass % with respect to a total mass of said polyolefin dividable composite fibers, said high strength fibers and said polyolefin heat-sensitive-adhesive fibers;
• subjecting the resulting fiber web to a heat-fusing treatment and a hydro-entangling treatment, to obtain a heat-fused and hydro-entangled nonwoven fabric, and then, imparting a hydrophilic property to the resulting heat-fused and hydro-entangled nonwoven fabric.