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:
Jun. 29, 1976
Filed:
May. 08, 1974
Applicant:
Inventors:
Yuriko Igarashi, Musashino, JA;
Haruko Kakutani, Tokyo, JA;
Assignee:
Kureha Kagaku Kogyo Kabushiki Kaisha, Tokyo, JA;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B32B / ; B32B / ; B32B / ;
U.S. Cl.
CPC ...
428212 ; 156272 ; 156297 ; 156334 ; 1791 / ; 204165 ; 307 / ; 428213 ; 428215 ; 428334 ; 428335 ; 428336 ; 428409 ; 428412 ; 428421 ; 428480 ; 428483 ; 428520 ; 428522 ;
Abstract
A layered electret retaining a high surface potential for a prolonged period of time or substantially permanently consisting of a laminate of a plurality of unit electrets which are formed of a sheet of a synthetic plastic material, each side of the laminate having been covered by a thin film of a high molecular weight substance having a higher electric resistivity than that of the material of the unit electrets. In one modification, the thin film of the high molecular weight substance has been, in addition, interposed between adjacent unit electrets.