| 摘要 |
PROBLEM TO BE SOLVED: To provide a separator for a battery having a liquid excellently hold ing property by giving a hydrophilic treatment for a nonwoven fabric made of very fine fiber, having a large specific surface area, serving as a thin film, and capable of being easily manufacturing. SOLUTION: This separator is composed of such a three layers structure that one nonwoven fabric layer made from a polyolefin derived fiber, namely a fine fiber having a mean fiber diameter of 5μm or less is set to an intermediate layer, and another nonwoven fabric layers made from a polyolefin derived fiber, having a mean fiber diameter of 5-20μm are set to be an upper layer and a lower layer. In the separator, a hydrophilic treatment for the nonwoven fabric is given which is a total basis weight of 20-90 g/m<2> , and the intermediate layer is set to a melt blow nonwoven fabric layer and the upper and lower layers are set to a span pound nonwoven fabric layer.
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