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US4859836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Melt-shapeable fluoropolymer compositions
Assignee: Tyco International Ltd Bermuda
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Filing: 1986-08-14
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Granted: 1989-08-22
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Expires: 2006-08-14
Abstract
Abstract Melt-shapeable polymeric compositions comprising a first fluoropolymer of relatively low crystallinity, e.g. a copolymer of tetrafluoroethylene and a perfluorinated comonomer, and a second fluoropolymer of relatively high crystallinity, especially a fluoropolymer obtained by irradiating PTFE or another fluoropolymer which cannot be melt-shaped in the absence of other polymers. The weight ratio of the first to the second polymer is preferably 0.3:1 to 2.5:1. The compositions have a wide variety of uses, for example as insulating materials or, if they contain carbon black or another conductive filler, as PTC conductive polymers.
Inventors
- 👤 Hans E. Lunk
- 👤 Donald A. Reed
- 👤 Marguerite E. Deep
- 👤 Charles Hill
- 👤 Andrew Au
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:29
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/028; C; C08; C08L; C08L27/00; C08L27/02; C08L27/12; C08L27/18; H01B; H01B1/00; H01B1/20; H01B1/24; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/443; H01B3/445; C08L2205/00; C08L2205/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
101 words
An electrical device which comprises (1) a melt-shaped conductive polymer element which comprises a polymeric component and, dispersed therein, a particulate conductive filler, said polymeric component comprising a mixture of (A) a first fluoropolymer which has a crystallinity of less than 45% and which can be melt-shaped in the absence of other polymers, and (B) a second crystalline fluoropolymer which is polytetrafluoroethylene and which has a crystallinity of at least 50%, and (2) at least two electrodes which can be connected to a source of electrical power and which, when so connected, cause current to flow through the conductive polymer element.
Claim 2
Dependent Claim
101 words
An electrical device which comprises (1) a melt-shaped conductive polymer element which comprises a polymeric component and, dispersed therein, a particulate conductive filler, said polymeric component comprising a mixture of (A) a first fluoropolymer which has a crystallinity of less than 45% and which can be melt-shaped in the absence of other polymers, and (B) a second crystalline fluoropolymer which is polytetrafluoroethylene and which has a crystallinity of at least 50%, and (2) at least two electrodes which can be connected to a source of electrical power and which, when so connected, cause current to flow through the conductive polymer element.
Claim 3
Dependent Claim
14 words
A device according to claim 1 wherein the conductive polymer element exhibits PTC behavior.
Claim 4
Dependent Claim
55 words
A device according to claim 2 wherein the conductive polymer element has a resistivity at 23° C. of 1 to 10 6 ohm.cm and comprises a carbon black having a particle size D of 20 to 150 millimicrons and a surface area S in m 2 /gram such that S/D is not more than 10.
Claim 5
Dependent Claim
35 words
A device according to claim 3 wherein the device is a circuit protection device having a resistance of less than 100 ohms and the conductive polymer element has a resistivity of less than 100 ohm.cm.
Claim 6
Dependent Claim
59 words
A device according to claim 2 wherein the first fluoropolymer has a melt viscosity at 380° C. of 5×10 3 to 1×10 6 poise, and the second fluoropolymer has a melt viscosity at 380° C. of less than 10 6 poise and the ratio by weight of the first fluoropolymer to the second fluoropolymer is from 0.3:1 to 5:1.
Claim 7
Dependent Claim
68 words
A device according to claim 2 wherein the polymeric component comprises a mixture of (1) a tetrafluoroethylene copolymer which is selected from (a) copolymers of tetrafluoroethylene and hexafluoropropylene and (b) copolymers of tetrafluoroethylene and a perfluorinated vinyl ether, and (2) polytetrafluoroethylene which has been irradiated to a dose of 5 to 30 Mrad, the ratio by weight of polymer (1) to polymer (2) being from 0.3:1 to 5:1.
Claim 8
Dependent Claim
22 words
A device according to claim 1, wherein the first and second fluoropolymers constitute at least 85% by weight of the polymeric component.
Claim 9
Dependent Claim
20 words
A device according to claim 1, wherein the polytetrafluoroethylene has been irradiated to a dose of 2.5 to 40 Mrad.
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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) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |