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US 5,178,797 AGranted
Conductive polymer compositions having improved properties under electrical stress
AssigneeRaychem Corporation
InventorJoseph H. Evans
Life of this patent
Estimating the term…
Abstract
Conductive polymer compositions comprise carbon black or graphite dispersed in a polymer and further comprise an arc-controlling additive such as alumina hydrate. Such compositions have improved performance when subjected to electrical stress and are, therefore, particularly useful in circuit protection devices.
Claims20
A conductive polymer composition which has a resistivity at 23.degree. C. of less than 10.sup.6 ohm-cm and which comprises
- (1) an organic polymer component which is present in amount 20 to 91% by volume of the composition;
- (2) a conductive filler component which consists essentially of carbon black or graphite or a mixture of carbon black and graphite, which has been dispersed in said polymer component and which is present in amount 4 to 65% by volume of the composition;
- and
- (3) an arc-controlling additive which is a particulate material and which has been dispersed in said polymer component.
1 more element
A composition which exhibits PTC behavior, which has a resistivity at 23.degree. C. of less than 10.sup.6 ohm-cm and which comprises
- (1) an organic polymer component which is present in amount 20 to 91% by volume of the composition;
- (2) a conductive filler component which consists essentially of carbon black or graphite or a mixture of carbon black and graphite, which has been dispersed in said polymer component and which is present in amount 4 to 65% by volume of the composition;
- and
- (3) an arc-controlling additive which is a particulate material and which has been dispersed in said polymer component.
1 more element
An electrical device which comprises
- (A) a PTC element composed of a conductive polymer composition which exhibits PTC behavior, which has a resistivity at 23.degree. C. of less than 10.sup.6 ohm.cm, and which comprises
- (1) an organic polymer component which is present in amount 20 to 91% by volume of the composition and which has at least 10% crystallinity;
- (2) a conductive filler component which consists essentially of carbon black, which has been dispersed in said polymer component, and which is present in amount 4 to 65% by volume of the composition;
- and
- (3) an arc-controlling additive which is a particulate material and which has been dispersed in said polymer component and
- (B) at least two electrodes which can be connected to a source of electrical power and which when so connected cause current to flow through the PTC element.
3 more elements
Dependencies are inferred from the claim text.