US5250226A
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Electrical devices comprising conductive polymers
Assignee: Tyco International Ltd
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Filing: 1988-06-03
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Granted: 1993-10-05
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Expires: 2008-06-03
Abstract
Abstract Conductive polymer compositions which exhibit PTC behavior comprising a first polymeric component which may be crystalline, a second component, and a particulate conductive filler. The second component may comprise either a polymer which exhibits side chain crystallization or a crystalline material which has a sharp melting point and has poor physical properties at room temperature and/or exhibits no melt strength at elevated temperatures. The compositions are particularly useful in electrical devices which exhibit "square" resistance vs. temperature characteristics.
Inventors
- 👤 Ravinder K. Oswal
- 👤 Amitkumar N. Dharia
- 👤 Leonard Barrett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:32
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/028
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
93 words
A conductive polymer composition which exhibits PTC behavior and which comprises (1) a first polymeric component which comprises a crystalline organic polymer which (i) has a melting point T m1 , and (ii) has a crystallinity of at least 10%. (2) a second polymeric component which (i) exhibits side chain crystallization, (ii) has a melting point T m2 which is within the range (T m1 -150)°C. to (T m1 +50)°C., and (iii) comprises a vinyl polymer having a linear side chain comprising at least eight carbon atoms; and (3) a particulate conductive filler.
Claim 2
Dependent Claim
93 words
A conductive polymer composition which exhibits PTC behavior and which comprises (1) a first polymeric component which comprises a crystalline organic polymer which (i) has a melting point T m1 , and (ii) has a crystallinity of at least 10%. (2) a second polymeric component which (i) exhibits side chain crystallization, (ii) has a melting point T m2 which is within the range (T m1 -150)°C. to (T m1 +50)°C., and (iii) comprises a vinyl polymer having a linear side chain comprising at least eight carbon atoms; and (3) a particulate conductive filler.
Claim 3
Dependent Claim
17 words
A composition according to claim 1 wherein the linear side chain comprises 10 to 18 carbon atoms.
Claim 4
Dependent Claim
23 words
A composition according to claim 1 wherein the second polymeric component has a weight average molecular weight of at least 5×10 4 .
Claim 5
Dependent Claim
23 words
A composition according to claim 3 wherein the second polymeric component has a weight average molecular weight of at least 8×10 4 .
Claim 6
Dependent Claim
23 words
A composition according to claim 4 wherein the second polymeric component has a weight average molecular weight of at least 1×10 5 .
Claim 7
Dependent Claim
22 words
A composition according to claim 1 wherein the second polymeric component comprises the polymer of a vinyl ester of a fatty acid.
Claim 8
Dependent Claim
14 words
A composition according to claim 6 wherein the second polymeric component comprises poly(vinyl stearate).
Claim 9
Dependent Claim
19 words
A composition according to claim 7 wherein the poly(vinyl stearate) has a melting temperature between 30° and 50° C.
Claim 10
Dependent Claim
18 words
A composition according to claim 1 wherein the first polymeric component has a crystallinity of at least 5%.
Claim 11
Dependent Claim
24 words
A composition according to claim 9 wherein the first polymeric component comprises at least 15% by weight of repeating units derived from a cycloolefin.
Claim 12
Dependent Claim
24 words
A composition according to claim 10 wherein the first polymeric component comprises at least 50% by weight of repeating units derived from a cycloolefin.
Claim 13
Dependent Claim
24 words
A composition according to claim 10 wherein the first polymeric component comprises a polymer of cyclooctenamer having a trans content of 55 to 90%.
Claim 14
Dependent Claim
23 words
A composition according to claim 1 wherein the first polymeric component has a melting point in the range of 0° to 80° C.
Claim 15
Dependent Claim
23 words
A composition according to claim 13 wherein the first polymeric component has a melting point in the range of 20° to 50° C.
Claim 16
Dependent Claim
13 words
A composition according to claim 1 wherein the conductive filler comprises carbon black.
Claim 17
Dependent Claim
35 words
A composition according to claim 15 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 18
Dependent Claim
21 words
A composition according to claim 1 wherein the second polymeric component comprises not more than 15% by weight of the composition.
Claim 19
Dependent Claim
20 words
A composition according to claim 1 wherein T m2 is within the range (T m1 -150)°C. to (T m1 +50)°C.
Claim 20
Dependent Claim
13 words
A composition according to claim 1 which comprises (4) an inorganic particulate filler.
Claim 21
Dependent Claim
29 words
A composition according to claim 21 wherein the inorganic filler is zinc oxide and it is present in an amount not more than 30% by weight of the composition.
Claim 22
Dependent Claim
119 words
A conductive polymer composition which exhibits PTC behavior and which comprises (1) a first polymeric component which comprises an organic polymer; (2) a second component which (i) has a crystallinity of at least 10%, (ii) has a sharp melting point T m2 such that the temperature range from the start of melting to the completion of melting as determined from a DSC curve is less than 30° C., and (iii) when exposed to temperatures above T m2 has no melt strength, and (iv) comprises a vinyl polymer having a linear side chain comprising at least eight carbon atoms; and (3) a particulate conductive filler; the ratio of the first polymeric component to the second component being 10:1 to 2:1.
Claim 23
Dependent Claim
119 words
A conductive polymer composition which exhibits PTC behavior and which comprises (1) a first polymeric component which comprises an organic polymer; (2) a second component which (i) has a crystallinity of at least 10%, (ii) has a sharp melting point T m2 such that the temperature range from the start of melting to the completion of melting as determined from a DSC curve is less than 30° C., and (iii) when exposed to temperatures above T m2 has no melt strength, and (iv) comprises a vinyl polymer having a linear side chain comprising at least eight carbon atoms; and (3) a particulate conductive filler; the ratio of the first polymeric component to the second component being 10:1 to 2:1.
Claim 24
Dependent Claim
14 words
A composition according to claim 21 wherein the first polymeric component is an elastomer.
Claim 25
Dependent Claim
24 words
A composition according to claim 21 wherein the first polymeric component is a crystalline organic polymer which has a melting temperature T m1 .
Claim 26
Dependent Claim
16 words
A composition according to claim 21 wherein the first polymeric component is an amorphous thermoplastic polymer.
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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) | 1996-10-04 | 1997-04-05 | 1997-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-04 | 2001-04-05 | 2001-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-04 | 2005-04-05 | 2005-10-05 | $7700.00 | Window Closed / Lapsed |