SEPARATOR FOR ALUMINUM ELECTROLYTIC CAPACITORS, AND ALUMINUM ELECTROLYTIC CAPACITOR

A separator for aluminum electrolytic capacitors interposed between paired electrodes contains a synthetic resin fiber, and has porosity within a range of 65 to 85%, average pore size within a range of 0.5 to 25.0 µm, and Clark stiffness within a range of 1 to 10 cm3/100. Moreover, the separator is nonwovens including this structure. Furthermore, use of the separator in solid electrolytic capacitors and hybrid electrolytic capacitors allows reduction in initial ESR and short circuit defect rate, and improvement in reliability of being able to endure use over a long period of time in a severe environment. Yet further, the separator may be used in an aluminum electrolytic capacitor using a conductive polymer as a cathode material.