Patent US5195013A successfully refreshed from Google Patents.
US5195013A
Expired / Lapsed
US
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PTC conductive polymer compositions
Assignee: Tyco International Ltd Bermuda
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Filing: 1992-04-13
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Granted: 1993-03-16
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Expires: 2012-04-13
Abstract
Abstract Conductive polymer PTC compositions have improved properties, especially at voltages of 200 volts or more, if they are very highly cross-linked by means of irradiation, for example to a dosage of at least 50 Mrads, preferably at least 80 Mrads, e.g. 120 to 600 Mrads. The cross-linked compositions are particularly useful in circuit protection devices and layered heaters.
Inventors
- 👤 Stephen M. Jacobs
- 👤 Mary S. McTavish
- 👤 Frank A. Doljack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:45
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/027
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
83 words
An electrical circuit which comprises (a) a power source having a voltage V which is at least 200 volts; (b) an electrical load; and (c) a circuit protection device which comprises (i) a radiation cross-linked PTC conductive polymer element, and (ii) two electrodes which are connected to the power source so that current passes through the PTC element; said device when subjected to SEM scanning, showing a maximum difference in voltage between two points separated by 10 microns of less than 3 volts.
Claim 2
Dependent Claim
83 words
An electrical circuit which comprises (a) a power source having a voltage V which is at least 200 volts; (b) an electrical load; and (c) a circuit protection device which comprises (i) a radiation cross-linked PTC conductive polymer element, and (ii) two electrodes which are connected to the power source so that current passes through the PTC element; said device when subjected to SEM scanning, showing a maximum difference in voltage between two points separated by 10 microns of less than 3 volts.
Claim 3
Dependent Claim
24 words
A circuit according to claim 1 wherein the cross-linked PTC conductive polymer element has a resistivity at 23° C. of less than 50 ohm-cm.
Claim 4
Dependent Claim
33 words
A circuit according to claim 1 wherein the conductive polymer composition of the circuit protection device comprises a polymeric component and, dispersed in the polymeric component, a particulate conductive filler comprising carbon black.
Claim 5
Dependent Claim
18 words
A circuit according to claim 3 wherein the polymeric component consists essentially of one or more crystalline polymers.
Claim 6
Dependent Claim
13 words
A circuit according to claim 4 wherein the polymeric component comprises a polyolefin.
Claim 7
Dependent Claim
14 words
A circuit according to claim 5 wherein the polymeric component consists essentially of polyethylene.
Claim 8
Dependent Claim
91 words
An electrical circuit which comprises (a) a power source having a voltage V which is at least 200 volts; (b) an electrical load; and (c) a circuit protection device which comprises (i) a radiation cross-linked PTC conductive polymer element, and (ii) two columnar electrodes which are embedded in the PTC element and are connected to the power source so that current flows through the PTC element; said device, when subjected to SEM scanning, showing a maximum difference in voltage between two points separated by 10 microns of less than 4.2 volts.
Claim 9
Dependent Claim
91 words
An electrical circuit which comprises (a) a power source having a voltage V which is at least 200 volts; (b) an electrical load; and (c) a circuit protection device which comprises (i) a radiation cross-linked PTC conductive polymer element, and (ii) two columnar electrodes which are embedded in the PTC element and are connected to the power source so that current flows through the PTC element; said device, when subjected to SEM scanning, showing a maximum difference in voltage between two points separated by 10 microns of less than 4.2 volts.
Claim 10
Dependent Claim
32 words
A circuit according to claim 7 wherein said device, when subject to SEM scanning, shows a maximum difference in voltage between two points separated by 10 microns of less than 3.0 volts.
Claim 11
Dependent Claim
33 words
A circuit according to claim 7 wherein the conductive polymer composition of the circuit protection device comprises a polymeric component and, dispersed in the polymeric component, a particulate conductive filler comprising carbon black.
Claim 12
Dependent Claim
12 words
A circuit according to claim 9 wherein the polymeric component comprises polyethylene.
Claim 13
Dependent Claim
24 words
A circuit according to claim 7 wherein the cross-linked PTC conductive polymer element has a resistivity at 23° C. of less than 50 ohm-cm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-03-15 | 1996-09-14 | 1997-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-15 | 2000-09-14 | 2001-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-15 | 2004-09-14 | 2005-03-16 | $7700.00 | Window Closed / Lapsed |