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. 25, 1978
Filed:
Nov. 26, 1976
Applicant:
Inventor:
Anupama Mishra, Guelph, CA;
Assignee:
Uniroyal Ltd., , CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01B / ;
U.S. Cl.
CPC ...
307 / ; 252 632 ; 361233 ;
Abstract
An electret made of styrene-type polymer (e.g., polystyrene), having a volume resistivity of at least 10.sup.16 ohm-cm and a glass transition temperature above 50.degree. C, and containing not more than 1% by weight of electron-donor impurities and not more than 0.5% by weight of electron-acceptor impurities, said electret being capable of retaining at least 75% of its charge after exposure to a temperature of 50.degree. C and a relative humidity of 100% for 100 days.