Electret and filter using the same

Abstract

It is provided that an electret having excellent filtering performance and a filter using the electret even in a case where polyolefin resin and magnesium element are contained. An electret comprising a polyolefin resin and a nitrogen-containing compound, wherein 0.1 to 5 parts by mass of the nitrogen-containing compound is contained to 100 parts by mass of the polyolefin resin, a proportion of a magnesium element contained in the electret is 5 to 100 ppm, and a QF value represented by the following formula is not less than 1.00 mmAq−1 when particles having particle diameters of 0.3 to 0.5 μm are to be collected. QF [mmAq−1]=−[ln(particle penetration(%)/100)]/[ventilation resistance (mmAq)]

Dependencies are inferred from the claim text.