SEPARATOR FOR ELECTRIC DOUBLE LAYER CAPACITOR

The purpose of the present invention is to realize a separator that has excellent thermal stability in size, shape and the like even in a high temperature environment. The separator comprises a nonwoven fabric obtained by subjecting nonwoven fabric comprising homo-PAN fibers to a flame proofing process in a temperature range of 210 DEG C to 300 DEG C, wherein the value of ID/IN, which is the ratioof an absorption peak intensity ID of a carbon double bond-derived region (1580 to 1610 cm-1) of the homo-PAN nonwoven fabric as determined by infrared absorption spectroscopy, to an absorption peakintensity IN derived from a nitrile group (2240 cm), is not less than 0.07, and wherein the fiber shape and size are stably maintained after immersion for 30 minutes in an electrolytic solution at140 DEG C including propylene carbonate. 本发明的目的在于，实现种即使在高温环境下，尺寸、形状等的热稳定性也优异的隔膜。由将由均聚PAN纤维构成的无纺布在210～300℃的温度范围内进行耐热化处理的无纺布构成，在该均聚PAN无纺布的红外吸收光谱分析中，碳碳双键特征区域(1580～1610cm)中的吸收峰值强度I，与腈基特征区域(2240cm)中的吸收峰值强度I的比I/I的值为0.07以上，而且，在含有碳酸丙烯