Patent ID: 11908629
Assignee: SEKISUI CHEMICAL CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 7:
8. A method of manufacturing an electret sheet, comprising:
an extrusion step of obtaining a synthetic resin sheet;
an aging step of aging the synthetic resin sheet obtained in the extrusion step such that a surface temperature of the synthetic resin sheet becomes [(a melting point of a synthetic resin)−30° C.] or higher and [(the melting point of the synthetic resin resin)−1° C.] or lower;
a stretching step of uniaxially stretching the synthetic resin sheet after the aging step;
an annealing step of annealing the synthetic resin sheet after the stretching step; and
a charging step of charging the synthetic resin sheet, and
wherein the electret sheet is the electret sheet according to claim 1.