Patent ID: 8477480

Claim:
A separator for capacitors comprising a laminate comprising a nanofiber layer and a base layer, the laminate at least comprising the nanofiber layer on one surface or both surfaces thereof; the nanofiber layer comprising polyamide filaments formed from a polyamide (a) and having an average fiber diameter of 10 to 600 nm, and the base layer comprising fibers at least including polyamide fibers formed from a polyamide (a); and the polyamide (a) comprising a dicarboxylic acid unit and a diamine unit, (i) the dicarboxylic acid unit comprising a terephthalic acid unit in the proportion of not lower than 60% by mole, and (ii) the diamine unit comprising at least one diamine unit selected from the group consisting of 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit in the proportion of not lower than 60% by mole in total, wherein the nanofiber layer has a basis weight of 0.1 to 5 g/m 2 , and the ratio of base layer thickness to nanofiber layer thickness is 0.8:1 to 3.5:1.