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US 5,181,006 AGranted
Method of making an electrical device comprising a conductive polymer composition
AssigneeRaychem Corporation
InventorsJeff Shafe, O. James Straley, Gordon McCarty, Ravinder K. Oswal, Amitkumar N. Dharia
Life of this patent
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Abstract
A polymer thick film ink which exhibits PTC behavior comprising an organic polymer which is crystalline, an active solvent suitable for dissolving the polymer, and carbon black which has a pH of less than 4.0. The ink is particularly useful in producing electrical devices such as heaters and circuit protection devices.
Claims18
A method for producing an electrical device which comprises a conductive polymer which exhibits PTC behavior, said method comprising
- (1) mixing (a) carbon black which has a pH of less than 4.0, (b) an organic polymer which has a crystallinity of at least 5% and a melting point T.sub.m, and (c) an active solvent for the polymer;
- (2) allowing the polymer to dissolve in the solvent to form an ink;
- (3) applying the ink to a substrate to form a resistive element which, when cured, will exhibit PTC behavior;
- and
- (4) curing the ink by heating at a temperature T.sub.c for a time sufficient to remove the solvent.
2 more elements
An electrical device which comprises
- (1) a first electrode,
- (2) a second electrode, and
- (3) a resistive element which exhibits PTC behavior and which is supported by a substrate and which has been prepared by
- (a) mixing (i) carbon black which has a pH of less than 4.0, (ii) an organic polymer which has a crystallinity of at least 5% and a melting point T.sub.m, and (iii) an active solvent for the polymer;
- (b) allowing the polymer to dissolve in the solvent to form an ink;
- applying the ink to the substrate to form the resistive element which, when cured, will exhibit PTC behavior;
- and
- (d) curing the ink by heating at a temperature T.sub.c for a time sufficient to remove the solvent,
- the first and the second electrodes being connectable to a source of electrical power to pass current between the electrodes.
6 more elements
Dependencies are inferred from the claim text.