| 摘要 |
PROBLEM TO BE SOLVED: To obtain a hydrophilic non-woven fabric having a cost merit capable of highly sulfonating even under a moderate sulfonation-treating condition and having less reduction of the strength of the non-woven fabric, and a battery separator maintaining good battery performance while improving its self discharging performance. SOLUTION: This hydrophilic non-woven fabric having a rapid sulfonation reaction rate and hydrophilic property in a state of having a small reduction of a non-woven fabric strength is obtained by sulfonation-treating a fibrous aggregate containing at least 5 wt.% thermoplastic synthetic fiber in which on at least a part of the fiber surface, a copolymer or mixture with propylene having <20 wt.% ethylene content is exposed. For example, in the case that the thermoplastic synthetic fiber is an ethylene-propylene copolymer containing 3-20 wt.% ethylene content, it is suitable in points that the sulfonation reaction rate is rapid, its adhesion strength is excellent and the reduction of the non- woven fabric strength is small.
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