The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 13, 2021
Filed:
Feb. 03, 2017
Sekisui Chemical Co., Ltd., Osaka, JP;
Tetsuhiro Kato, Osaka, JP;
Nobuto Kamiya, Osaka, JP;
Masahiro Tsuchiya, Osaka, JP;
Yuuta Katsurayama, Osaka, JP;
Yasuyuki Shirasaka, Osaka, JP;
SEKISUI CHEMICAL CO., LTD., Osaka, JP;
Abstract
The present invention provides an electret sheet that retains high piezoelectricity under high-temperature condition. The electret sheet of the invention is characterized by including a charged porous sheet, in which the electret sheet has a volume resistivity of 1.0×10Ω·cm or more at 25° C. and a dielectric breakdown voltage of 7 kV or more at 25° C. The electret sheet preferably having a volume resistivity of 1.0×10Ω·cm or more at 37° C. and a dielectric breakdown voltage of 7 kV or more at 37° C. retains excellent piezoelectricity even after being left under a high-temperature atmosphere over a long period.