Process and apparatus for manufacturing an electret article

Abstract

A process for electret treatment is described, involving (1) placing the dielectric article between a combination of a first ion-repulsive electrode and a first ion-attractive electrode and between a combination of a second ion-repulsive electrode and a second ion-attractive electrode, under a specified arrangement; (2) supplying a first positive ion and a first negative ion from a first ion generating means between the dielectric article and the first ion-repulsive electrode, the first ion generating means being selected from an alternating current surface discharge element and an alternating current corona-type ion generating element; (3) applying a direct current voltage between the first ion-repulsive electrode and the first ion-attractive electrode to produce a first potential difference therebetween, whereby only one of the first positive and negative ions is moved in a specified direction, and is transferred on the dielectric article; (4) supplying a second positive ion and a second negative ion from a second ion generating means between the dielectric article and a second ion-repulsive electrode, the second ion generating means being selected from specified elements; and (5) applying a direct current voltage between the second ion-repulsive electrode and the second ion-attractive electrode to produce a second potential difference therebetween, whereby only the second ion having polarity opposite to polarity of the first ion transferred on the dielectric article is moved in a specified direction, and is transferred on the dielectric article.