US4910389A
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Conductive polymer compositions
Assignee: Tyco International Ltd
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Filing: 1988-06-03
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Granted: 1990-03-20
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Expires: 2008-06-03
Abstract
Abstract A conductive polymer composition which exhibits PTC behavior comprises a crystalline organic polymer, carbon black, and a high resistivity particulate filler. The high resistivity filler is semiconductive and has a resistivity at least 100 times that of the carbon black. Compositions of the invention exhibit good resistance stability when exposed to thermal cycling. They are useful in electrical devices requiring compositions with high resistivity.
Inventors
- 👤 Edward S. Sherman
- 👤 Mark S. Thompson
- 👤 Andrew Tomlinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:26
CPC Classifications
H; H01; H01C; H01C17/00; H01C17/22; H01C17/232; H01C7/00; H01C7/02; H01C7/027; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
120 words
A conductive polymer composition which exhibits stable PTC behavior and which comprises (1) a crystalline organic polymer which has a melting point T m ; (2) a first particulate conductive filler which (i) comprises carbon black, (ii) has a particle size D 1 , and (iii) is present at a volume loading V 1 ; and (3) a second particulate filler which (i) is semiconductive, (ii) has a particle size D 2 , and (iii) is present at a volume loading V 2 , wherein (a) the resistivity of the second filler p 2 is at least 100 times the resistivity of the first filler p 1 , and (b) the resistivity of the composition is at least 100 ohm-cm.
Claim 2
Dependent Claim
120 words
A conductive polymer composition which exhibits stable PTC behavior and which comprises (1) a crystalline organic polymer which has a melting point T m ; (2) a first particulate conductive filler which (i) comprises carbon black, (ii) has a particle size D 1 , and (iii) is present at a volume loading V 1 ; and (3) a second particulate filler which (i) is semiconductive, (ii) has a particle size D 2 , and (iii) is present at a volume loading V 2 , wherein (a) the resistivity of the second filler p 2 is at least 100 times the resistivity of the first filler p 1 , and (b) the resistivity of the composition is at least 100 ohm-cm.
Claim 3
Dependent Claim
16 words
A composition according to claim 1 wherein p 2 is 10 -1 to 10 8 ohm-cm.
Claim 4
Dependent Claim
15 words
A composition according to claim 2 wherein p 2 is 1 to 10 6 ohm-cm.
Claim 5
Dependent Claim
15 words
A composition according to claim 3 wherein p 2 is 10 to 10 5 ohm-cm.
Claim 6
Dependent Claim
17 words
A composition according to claim 1 wherein the resistivity of the composition is at leas 1000 ohm-cm.
Claim 7
Dependent Claim
17 words
A composition according to claim 5 wherein the resistivity of the composition is at least 10,000 ohm-cm.
Claim 8
Dependent Claim
14 words
A composition according to claim 1 wherein D 2 is 0.2 to 1.0 micron.
Claim 9
Dependent Claim
14 words
A composition according to claim 7 wherein D 2 is 0.3 to 0.9 micron.
Claim 10
Dependent Claim
14 words
A composition according to claim 8 wherein D 2 is 0.35 to 0.8 micron.
Claim 11
Dependent Claim
18 words
A composition according to claim 1 wherein the ratio D 2 to D 1 is 1:5 to 1:20.
Claim 12
Dependent Claim
18 words
A composition according to claim 10 wherein the ratio D 2 to D 1 is 1:7 to 1:15.
Claim 13
Dependent Claim
17 words
A composition according to claim 1 wherein p 2 is at least 1000 times p l .
Claim 14
Dependent Claim
24 words
A composition according to claim 1 wherein the total loading by volume of the first and second fillers V t is 20 to 50%.
Claim 15
Dependent Claim
13 words
A composition according to claim 13 wherein V t is 25 to 45%.
Claim 16
Dependent Claim
13 words
A composition according to claim 14 wherein V t is 30 to 40%.
Claim 17
Dependent Claim
19 words
A composition according to claim 13 wherein the ratio of V 1 to V 2 is 20:80 to 40:60.
Claim 18
Dependent Claim
19 words
A composition according to claim 16 wherein the ratio of V 1 to V 2 is 25:75 to 35:65.
Claim 19
Dependent Claim
21 words
A composition according to claim 1 wherein the carbon black has a particle size D 1 from 30 to 60 millimicrons.
Claim 20
Dependent Claim
13 words
A composition according to claim 1 wherein the second filler is zinc oxide.
Claim 21
Dependent Claim
14 words
A composition according to claim 19 wherein the zinc oxide is doped with aluminum.
Claim 22
Dependent Claim
14 words
A composition according to claim 1 wherein the second filler has been surface treated.
Claim 23
Dependent Claim
17 words
A composition according to claim 21 wherein the surface treatment is a coating of a dispersing agent.
Claim 24
Dependent Claim
13 words
A composition according to claim 22 wherein the dispersing agent is propionic acid.
Claim 25
Dependent Claim
13 words
A composition according to claim 1 wherein the second filler exhibits NTC behavior.
Claim 26
Dependent Claim
159 words
An electrical device which exhibits PTC behavior and which comprises (1) a PTC element comprising a conductive polymer composition which exhibits PTC behavior and which comprises (a) a crystalline organic polymer which has a melting point T m ; (b) a first particulate conductive filler which (i) comprises carbon black, (ii) has a particle size D 1 , and (iii) is present at a volume loading V 1 ; and (c) a second particulate filler which (i) is semiconductive, (ii) has a particle size D 2 , and (iii) is present at a volume loading V 2 , wherein (A) the resistivity of the second filler p 2 is at least 100 times the resistivity of the first filler p 1 , and (B) the resistivity of the composition is at least 100 ohm-cm, 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 27
Dependent Claim
159 words
An electrical device which exhibits PTC behavior and which comprises (1) a PTC element comprising a conductive polymer composition which exhibits PTC behavior and which comprises (a) a crystalline organic polymer which has a melting point T m ; (b) a first particulate conductive filler which (i) comprises carbon black, (ii) has a particle size D 1 , and (iii) is present at a volume loading V 1 ; and (c) a second particulate filler which (i) is semiconductive, (ii) has a particle size D 2 , and (iii) is present at a volume loading V 2 , wherein (A) the resistivity of the second filler p 2 is at least 100 times the resistivity of the first filler p 1 , and (B) the resistivity of the composition is at least 100 ohm-cm, 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 28
Dependent Claim
14 words
A device according to claim 25 wherein the electrical device is a self-regulating heater.
Claim 29
Dependent Claim
12 words
A device according to claim 26 wherein the PTC element is laminar.
Claim 30
Dependent Claim
13 words
A device according to claim 27 wherein the electrodes comprise laminar metal sheets.
Claim 31
Dependent Claim
12 words
A device according to claim 28 wherein the electrodes comprise electrodeposited metal.
Claim 32
Dependent Claim
25 words
A device according to claim 25 wherein the electrical device is crosslinked to a level equivalent to an irradiation dose of 2 to 40 Mrad.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
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