US4514620A
Expired / Lapsed
US
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Conductive polymers exhibiting PTC characteristics
Assignee: Raychem Corp
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Filing: 1983-09-22
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Granted: 1985-04-30
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Expires: 2003-09-22
Abstract
Abstract Conductive polymer compositions which exhibit PTC behavior and comprise carbon black (or other particulate conductive filler) dispersed in a cross-linked polymer component comprising a cycloolefin polymer having a crystallinity of at least 5% and a melting point in the range 0° to 80° C. These compositions are particularly useful in the form of heaters which self regulate at a temperature in the range of 0° to 70° C. Such heaters are particularly useful for freeze protection and for heating human and other animal bodies.
Inventors
- 👤 Tai C. Cheng
- 👤 Bruce A. McKinley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:15
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/146; A; A61; A61F; A61F7/00; A61F7/007; C; C08; C08K; C08K3/00; C08K3/02; C08K3/04; H01; H01B; H01B1/00; H01B1/20; H01B1/24; H01C; H01C7/00; H01C7/02; H01C7/027; A61F2007/0001; A61F2007/0071; A61F2007/0073; A61F2007/0074
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
104 words
An electrical device which comprises a (1) a PTC element which is composed of a conductive polymer composition which exhibits PTC behavior and which comprises (a) a cross-linked polymer component which comprises at least 15% by weight of repeating units derived from a cycloolefin, which has a crystallinity of at least 5% and which has a crystalline melting point in the range of 0° to 80° C., and (b) a particulate conductive filler which is dispersed in said polymer; and (2) at least two electrodes which can be connected to a source of electrical power to cause current to flow through the PTC element.
Claim 2
Dependent Claim
104 words
An electrical device which comprises a (1) a PTC element which is composed of a conductive polymer composition which exhibits PTC behavior and which comprises (a) a cross-linked polymer component which comprises at least 15% by weight of repeating units derived from a cycloolefin, which has a crystallinity of at least 5% and which has a crystalline melting point in the range of 0° to 80° C., and (b) a particulate conductive filler which is dispersed in said polymer; and (2) at least two electrodes which can be connected to a source of electrical power to cause current to flow through the PTC element.
Claim 3
Dependent Claim
38 words
A device according to claim 1 wherein the polymer component comprises at least 50% by weight of a cycloolefin polymer in which at least 80% by weight of the repeating units are derived from at least one cycloolefin.
Claim 4
Dependent Claim
13 words
A device according to claim 2 wherein said cycloolefin is free from substituents.
Claim 5
Dependent Claim
34 words
A device according to claim 2 wherein the polymer component comprises a blend of 50 to 90% by weight of said cycloolefin polymer and 10 to 50% by weight of an acyclic olefin polymer.
Claim 6
Dependent Claim
23 words
A device according to claim 1 wherein the polymer component comprises a polymer of cyclooctenamer having a trans content of 60 to 90%.
Claim 7
Dependent Claim
15 words
A device according to claim 1 wherein the polymer component has been cross-linked by radiation.
Claim 8
Dependent Claim
23 words
A device according to claim 6 wherein the polymer component has been cross-linked by radiation to a dosage of 5 to 30 Mrad.
Claim 9
Dependent Claim
21 words
A device according to claim 1 wherein the polymer component has been cross-linked with the aid of a chemical cross-linking agent.
Claim 10
Dependent Claim
17 words
A device according to claim 1 which further comprises (3) an antioxidant which is a hindered phenol.
Claim 11
Dependent Claim
13 words
A device according to claim 9 wherein the antioxidant contains a 1,3-di-t-butyl-2-hydroxy group.
Claim 12
Dependent Claim
17 words
A device according to claim 9 wherein the antioxidant has a molecular weight of at least 600.
Claim 13
Dependent Claim
22 words
A device according to claim 1 which further comprises (3) an antioxidant which has a melting point of 40° to 100° C.
Claim 14
Dependent Claim
16 words
A device according to claim 1 wherein the particulate conductive filler consists essentially of carbon black.
Claim 15
Dependent Claim
35 words
A device according to claim 13 wherein the carbon black has a particle size (D) of 20 to 250 millimicrons and a surface area (S) such that the ratio S/D is not more than 10.
Claim 16
Dependent Claim
27 words
A device according to claim 1 wherein the PTC element has been prepared by melt-shaping and subsequently cross-linking a mixture of the polymer and the conductive filler.
Claim 17
Dependent Claim
24 words
A device according to claim 1 which is a strip heater comprising two elongate parallel electrodes which are embedded in an elongate PTC element.
Claim 18
Dependent Claim
11 words
A device according to claim 1 which is a sheet heater.
Claim 19
Dependent Claim
65 words
A conductive polymer composition which exhibits PTC behavior and which comprises (a) a cross-linked polymer component which comprises at least 15% by weight of repeating units derived from a cycloolefin, which has a crystallinity of at least 5% and which has a crystalline melting point in the range of 0° to 80° C., and (b) a particulate conductive filler which is dispersed in said polymer.
Claim 20
Dependent Claim
65 words
A conductive polymer composition which exhibits PTC behavior and which comprises (a) a cross-linked polymer component which comprises at least 15% by weight of repeating units derived from a cycloolefin, which has a crystallinity of at least 5% and which has a crystalline melting point in the range of 0° to 80° C., and (b) a particulate conductive filler which is dispersed in said polymer.
Claim 21
Dependent Claim
42 words
A composition according to claim 18 wherein the polymer is cyclooctenamer and the conductive filler is carbon black, and which further comprises an antioxidant which has a molecular weight of at least 600 and a melting point of 40° to 100° C.
Claim 22
Dependent Claim
38 words
A composition according to claim 18 wherein the polymer component comprises at least 50% by weight of a cycloolefin polymer in which at least 80% by weight of the repeating units are derived from at least one cycloolefin.
Claim 23
Dependent Claim
34 words
A composition according to claim 20 wherein the polymer component comprises a blend of 50 to 90% by weight of said cycloolefin polymer and 10 to 50% by weight of an acyclic olefin polymer.
Claim 24
Dependent Claim
15 words
A composition according to claim 18 wherein the polymer component has been cross-linked by radiation.
Claim 25
Dependent Claim
24 words
A composition according to claim 18 which further comprises an antioxidant which is a hindered phenol having a molecular weight of at least 600.
Claim 26
Dependent Claim
21 words
A composition according to claim 18 which further comprises an antioxidant which has a melting point of 40° to 100° C.
Claim 27
Dependent Claim
41 words
A composition according to claim 18 wherein the particulate conductive filler consists essentially of carbon black having a particle size (D) of 20 to 250 millimicrons and a surface area (S) such that the ratio S/D is not more than 10.
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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) | 1988-04-29 | 1988-10-29 | 1989-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-29 | 1992-10-29 | 1993-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-29 | 1996-10-29 | 1997-04-30 | $7700.00 | Window Closed / Lapsed |