Abstract: The present invention provide a separator for an electrochemical device which comprises a wet nonwoven fabric comprising one or more kinds of fibrillated organic fibers which are at least partially fibrillated into a fiber diameter of 1 &mgr;m or less, and one or more kinds of. unfibrillated organic fibers having a fineness of 0.5 dtex or less, which exhibits excellent heat resistance, electrolyte holding properties, internal short-circuit preventing property, and winding property, which results in a lowered internal resistance and prolonged life of an electrochemical device, and a method for producing the same and an electrochemical device.

Abstract: The present invention provides a non-woven fabric for an alkali cell separator capable of preventing active materials from transfer, and having distinguished electrolyte solution absorbability and retainability in spite of a small areal weight and also provides a process for producing the same. The non-woven fabric is substantially free from perforations and has a center surface average roughness SRa of not more than 13 .mu.m at streaks of entanglement on at least one side of the non-woven fabric, a maximum pore diameter of not more than 50 .mu.m and a water absorbability under pressure of not less than 20 g/m.sup.2, and a standard deviation of pore diameter distribution of not more than 20 .mu.m, as determined by bubble point method.