| 摘要 |
PROBLEM TO BE SOLVED: To provide a separator which is easily wettable with electrolyte with has a electrolyte-holding characteristic, superior in permeability of oxygen gas generated in charging, and highly strong by fixing resin fine particles having a specified particle size which is graft-polymerized with an ethylenic unsaturated acid and its ester to the surface of a fiber constituting a polyolefin nonwoven fabric. SOLUTION: As resin fine particles to be fixed to the fiber of a nonwoven fabric, for example, polyolefin resin is included, and its particles size is preferably 0.01-10 μm. In order to impart a hydrophilic property to the resin fine particle, it is necessary to graft-polymerize an ethylenic unsaturated fatty acid and its ester therewith. As the suitable ethylenic unsaturated fatty acid and its ester, acrylic acid, methacrylic acid or the like can be cited. Such resin fine particles are fixed by applying its aqueous dispersed body to the nonwoven fabric followed by heating. |
