Electret and filter using the same
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)]
1 . 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 not less than 16.3 ppm and less than 30.4 ppm, and
a QF value represented by the following formula is 1.52-1.61 mmAq−1 when particles having particle diameters of 0.3 to 0.5 μm are to be collected, where QF [mmAq−1]=−[ln (particle penetration (%)/100)]/[ventilation resistance (mmAq)].
2 . The electret according to claim 1 , comprising fatty acid magnesium salt.
3 . The electret according to claim 1 , wherein the nitrogen-containing compound contains a hindered-amine-based compound.
4 . A filter comprising the electret according to claim 1 .