WERKWIJZE VOOR HET VERVAARDIGEN VAN EEN ELEC- TREET FILTER EN ELECTREET FILTERS, VERKREGEN VOLGENS DEZE WERKWIJZE.

摘要

A method for forming a filter of electrically charged electret fiber material, consisting of a high molecular weight, nonpolar polymeric substance, comprising drawing, charging, and fibrillating a foil of said high molecular weight substance. The fibrillated foil is wound and then crimping is effected.