Elektret-Vliesstoff und Verfahren zu seiner Herstellung

摘要

The improved nonwoven fabric in an electret state is composed of monofilaments with an average fiber diameter of 0.5 - 100 mu m that are formed of a polymer composition containing no more than 1 mol% of polar groups; the fabric has a weight of 5 - 100 g/m<2>, a bulk density of 0.05 - 0.40 g/cm<3> and an average surface charge density of at least 0.1 x 10<-><9> C/cm<2>. This nonwoven fabric is capable of efficient dust collection and its trapping ability is retained for a prolonged time even in a hot and humid condition. Also disclosed are a process for producing this nonwoven fabric, as well as a filtering and an air masking material which are composed of that nonwoven fabric.