US5093036A
Expired / Lapsed
US
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Conductive polymer composition
Assignee: Littelfuse Inc
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Filing: 1988-09-20
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Granted: 1992-03-03
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Expires: 2008-09-20
Abstract
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.
Inventors
- 👤 Jeff Shafe
- 👤 O. James Straley
- 👤 Ravinder K. Oswal
- 👤 Gordon McCarty
- 👤 Amitkumar N. Dharia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:19
CPC Classifications
C; C09; C09D; C09D11/00; C09D11/52; H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/146; H01; H01B; H01B1/00; H01B1/20; H01B1/24; H01C; H01C7/00; H01C7/02; H01C7/027
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
50 words
A polymer thick film ink which exhibits PTC behavior, said ink comprising (1) an organic polymer which has a crystallinity of at least 5%; (2) an active solvent which is suitable for dissolving the polymer at room temperature; and (3) carbon black which has a pH of less than 4.0.
Claim 2
Dependent Claim
50 words
A polymer thick film ink which exhibits PTC behavior, said ink comprising (1) an organic polymer which has a crystallinity of at least 5%; (2) an active solvent which is suitable for dissolving the polymer at room temperature; and (3) carbon black which has a pH of less than 4.0.
Claim 3
Dependent Claim
17 words
An ink according to claim 1 wherein the carbon black has a pH of less than 3.0.
Claim 4
Dependent Claim
13 words
An ink according to claim 1 wherein the carbon black has been oxidized.
Claim 5
Dependent Claim
12 words
An ink according to claim 1 wherein the polymer comprises a fluoropolymer.
Claim 6
Dependent Claim
18 words
An ink according to claim 4 wherein the polymer comprises a terpolymer of vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene.
Claim 7
Dependent Claim
15 words
An ink according to claim 1 wherein the solvent comprises dimethyl formamide, isophorone, or cyclohexanone.
Claim 8
Dependent Claim
14 words
An ink according to claim 1 wherein the viscosity is 7500 to 10,000 cps.
Claim 9
Dependent Claim
16 words
An ink according to claim 1 wherein the polymer has a crystallinity of at least 10%.
Claim 10
Dependent Claim
16 words
An ink according to claim 8 wherein the polymer has a crystallinity of at least 15%.
Claim 11
Dependent Claim
10 words
An ink according to claim 1 which further comprises graphite.
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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) | 1995-03-03 | 1995-09-02 | 1996-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-03 | 1999-09-02 | 2000-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-03 | 2003-09-02 | 2004-03-03 | $7700.00 | Window Closed / Lapsed |