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:
Feb. 09, 1982
Filed:
Nov. 30, 1979
Lee M Middleman, Portola Valley, CA (US);
Alan J Gotcher, Saratoga, CA (US);
Raychem Corporation, Menlo Park, CA (US);
Abstract
Electrical devices comprising PTC elements have improved electrical stability when they comprise an oxygen barrier which restricts access of air to the element so that the PTC element absorbs oxygen at a rate less than 10.sup.-6 cc/sec/gram. The devices are for example circuit control devices or self-limiting heaters. Preferred PTC elements comprise a polymer having dispersed therein carbon black and an additive which stabilizes the polymer against degradation, especially an organic antioxidant. The oxygen barrier may for example be a layer of a polymeric composition or a self-supporting container principally made of metal and filled with an inert gas.