EP0138424A2
Expired / Lapsed
EP
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Electrical devices comprising conductive polymers exhibiting ptc characteristics
Assignee: Raychem Corp
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Filing: 1984-09-21
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Granted: —
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Expires: 2004-09-21
Abstract
Abstract Conductive polymer compositions which exhibit PTC behavior and which are useful, for example, in heating mammals and for other uses in which the surface of the heater must be maintained at a relatively low temperature. Preferred compositions comprise carbon black (or other particulate conductive filler) dispersed in a crosslinked polymer component comprising a cycloolefin polymer having a crystallinity of at least 5% and a melting point in the range 0°C to 80°C.
Inventors
- 👤 Tai Chun Cheng
- 👤 Bruce Alan Mckinley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 19:16
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: 12
Claim 1
Independent Claim
64 words
A conductive polymer composition which exhibits PTC behavior and which comprises (a) a 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 component.
Claim 2
Dependent Claim
64 words
A conductive polymer composition which exhibits PTC behavior and which comprises (a) a 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 component.
Claim 3
Dependent Claim
38 words
A composition 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
36 words
A composition according to Claim 1 or 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 5
Dependent Claim
26 words
A composition according to Claim 1, 2 or 3 wherein the polymer component comprises a polymer of cyclooctenamer having a trans content of 60 to 90%.
Claim 6
Dependent Claim
17 words
A composition according to any one of the preceding claims wherein the polymer component has been cross-linked.
Claim 7
Dependent Claim
23 words
A composition according to claim 5 wherein the polymer compnent has been cross-linked by radiation to a dosage of 5 to 30 Mrad.
Claim 8
Dependent Claim
24 words
A composition according to any one of the preceding claims which further comprises an antioxidant which has a melting point of 40° to 100°C.
Claim 9
Dependent Claim
30 words
A composition according to any one of the preceding claims which further comprises an antioxidant which is a hindered phenol and which has a molecular weight of at least 600.
Claim 10
Dependent Claim
49 words
An electrical device which comprises a PTC element which is composed of a conductive polymer composition as claimed in any one of the preceding claims, and at least two electrodes which can be connected to a source of electrical power to cause current to pass through the PTC element.
Claim 11
Independent Claim
105 words
A method of heating a mammal or other temperature sensitive substrate, which comprises bringing the substrate into conductive thermal contact with a self-regulating heater comprising (1) a PTC element which is composed of a conductive polymer composition which (a) exhibits PTC behavior and (b) comprises a particulate conductive y filler dispersed in a cross-linked polymer component comprising a crystalline organic polymer having a melting point of 20° to 80°C; and (2) at least two electrodes which are connected to a source of electrical power to cause current to pass through the PTC element, said heater having a maximum surface temperature which is less than 45°C.
Claim 12
Independent Claim
105 words
A method of heating a mammal or other temperature sensitive substrate, which comprises bringing the substrate into conductive thermal contact with a self-regulating heater comprising (1) a PTC element which is composed of a conductive polymer composition which (a) exhibits PTC behavior and (b) comprises a particulate conductive y filler dispersed in a cross-linked polymer component comprising a crystalline organic polymer having a melting point of 20° to 80°C; and (2) at least two electrodes which are connected to a source of electrical power to cause current to pass through the PTC element, said heater having a maximum surface temperature which is less than 45°C.
References Cited (Backward Citations)
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