| 摘要 |
PURPOSE:To obtain a substrate having liquid retention characteristics so high that it can retain liquid, such as electrolyte, at a high rate and keep its high retentivity even if being pressurized after retaining liquid once by a method wherein a laminate is made of a three-layer nonwoven fabric in which an intermediate layer is made of a nonwoven fabric of a rough structure and each outer layer is made of a nonwoven fabric of a dense structure. CONSTITUTION:A nonwoven fabric laminate is made of a three-layer nonwoven fabric in which each outer layer is made of a dense nonwoven fabric and an intermediate layer is made of a rough nonwoven fabric. The dense nonwoven fabric forming each outer layer preferably has an average fiber diameter of 0.05-15mum and is desirably produced by spraying melt fiber in a melt blow method in consideration of liquid retention characteristics and the like required as a battery separator and the like. If the dense nonwoven fabric forming each outer layer has an average fiber diameter less than 0.05mum, electrolyte or other liquid is hard to infiltrate into the laminate, and the laminate is hard to produce. On the other hand, if more than 15mum, liquid retained once is released by being pressurized. Therefore, a dense nonwoven fabric out of this range is insufficient in liquid retention characteristics as the requirement of a battery separator and the like. |
