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US 4,907,340 AGranted
Electrical device comprising conductive polymers
AssigneeRaychem Corporation
InventorsShou-Mean Fang, Charles H. Camphouse
Life of this patent
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Abstract
A process for preparing an electrical device which comprises a conductive polymer exhibiting PTC behavior. The device is irradiated by use of an electron beam at an average dose rate of less than 3.0 Mrad/minute. The cross-linking may be to a level of 50 to 100 Mrad or higher for devices designed to withstand high voltage test conditions. The device may be a laminar device comprising a center layer of higher resistivity than two surrounding layers.
Claims4
A process for the preparation of an electrical device which comprises
- (1) a PTC element composed of a cross-linked conductive polymer composition which exhibits PTC behavior and which comprises a polymeric component and, dispersed in the polymeric component, a particulate conductive filler;
- and
- (2) two electrodes which are electrically connected to the PTC element and which are connectable to a source of electrical power to cause current to pass through the PTC element,
- which process comprises subjecting the PTC element to radiation cross-linking in which (i) said cross-linking is achieved by use of an electron beam and (ii) the average dose rate is at most 3.0 Mrad/minute.
1 more element
Dependencies are inferred from the claim text.