Devices comprising conductive polymer compositions
First Claim
1. An electrical sheet heater which comprises:
- (1) a laminar resistive element which is composed of a conductive polymer composition which comprises an organic polymer, and dispersed in the polymer, a particulate filler;
(2) a plurality of electrodes at least two of which can be connected to a source of electrical power to cause current to pass through the laminar element, and which are dimensioned and positioned on a surface of the element so that when current passes between the electrodes, a substantial proportion of the current is parallel to the faces of the laminar element; and
(3) a dielectric layer positioned over at least part of the electrodes, the dielectric layer having been applied directly onto the electrodes in liquid form, and then solidified so that a solidified layer is formed having a first surface which is intimately bonded to at least part of the electrodes, and a second surface, facing away from the electrodes, with the proviso that if another member is bonded to the second surface of the solidified dielectric layer, at least one of the following conditions is satisfied (a) the peel strength of the bond between the said another member and the second surface of the dielectric layer is less than the peel strength of the bond between the first surface of the dielectric layer and the electrode; and
(b) the peel strength of the bond between the said another member and the second surface of the dielectric layer is less than 3 lbs. per inch at 20°
C.
2 Assignments
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Accused Products
Abstract
A number of improvements to electrical devices, particularly sheet heaters, comprising conductive polymer compositions, are provided. The preferred heater has the following features (a) it comprises a laminar resistive element and a plurality of electrodes which are so positioned that the predominant direction of current flow is parallel to the faces of the laminar element, (b) it comprises a laminar insulating element adjacent to but not secured to the electrodes and the resistive element; (c) it comprises a metallic foil, which acts as a ground plane and is positioned adjacent the insulating element but is not secured thereto; (d) it comprises a dielectric layer intimately bonded to the resistive element and to the electrodes.
The invention also provides an electrical device comprising first and second members having different resistivities, and a thin contact layer of intermediate resistivity positioned between the first and second members.
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Citations
13 Claims
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1. An electrical sheet heater which comprises:
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(1) a laminar resistive element which is composed of a conductive polymer composition which comprises an organic polymer, and dispersed in the polymer, a particulate filler; (2) a plurality of electrodes at least two of which can be connected to a source of electrical power to cause current to pass through the laminar element, and which are dimensioned and positioned on a surface of the element so that when current passes between the electrodes, a substantial proportion of the current is parallel to the faces of the laminar element; and (3) a dielectric layer positioned over at least part of the electrodes, the dielectric layer having been applied directly onto the electrodes in liquid form, and then solidified so that a solidified layer is formed having a first surface which is intimately bonded to at least part of the electrodes, and a second surface, facing away from the electrodes, with the proviso that if another member is bonded to the second surface of the solidified dielectric layer, at least one of the following conditions is satisfied (a) the peel strength of the bond between the said another member and the second surface of the dielectric layer is less than the peel strength of the bond between the first surface of the dielectric layer and the electrode; and
(b) the peel strength of the bond between the said another member and the second surface of the dielectric layer is less than 3 lbs. per inch at 20°
C. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification