Nonwoven fabric in an electret state and process for its production.

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.