US5328756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature sensitive circuit breaking element
Assignee: 3M Co
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Filing: 1992-01-31
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Granted: 1994-07-12
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Expires: 2012-01-31
Abstract
Abstract A composite article comprising a fibrillated polytetrafluoroethylene (PTFE) matrix, electrically conductive particles, and energy expandable, electrically nonconductive hollow polymeric particles, which composite is conductive and allows for the flow of electricity and which, upon attaining a temperature which causes expansion of the expandable polymeric particles, becomes insulating and causes the flow of electricity to cease. The articles are thin and can be used as electrical circuit breaking elements.
Inventors
- 👤 Robin E. Wright
- 👤 William V. Balsimo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:03
CPC Classifications
H; H01; H01H; H01H85/00; H01H85/02; H01H85/04; H01H85/05; H01H85/055; H01H85/06; H01B; H01B1/00; H01B1/20; H01B1/22; H01B1/24; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249971; Y10T428/249972; Y10T428/249986; Y10T428/31504; Y10T428/3154; Y10T428/31544
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
62 words
An electrically conductive composite article comprising a polytetrafluoroethylene fibril matrix having enmeshed therein (a) electrically conductive metal-containing particles, and (b) electrically nonconductive, energy expandable hollow polymeric particles, said composite article having a resistivity of less than about 1000 Ω.cm prior to expansion of said energy expandable particles and greater than about 10 5 Ω. cm after expansion of said energy expandable particles.
Claim 2
Dependent Claim
62 words
An electrically conductive composite article comprising a polytetrafluoroethylene fibril matrix having enmeshed therein (a) electrically conductive metal-containing particles, and (b) electrically nonconductive, energy expandable hollow polymeric particles, said composite article having a resistivity of less than about 1000 Ω.cm prior to expansion of said energy expandable particles and greater than about 10 5 Ω. cm after expansion of said energy expandable particles.
Claim 3
Dependent Claim
25 words
The composite article according to claim 1 wherein the weight ratio of conductive particles to nonconductive particles is in the range of 999:1 to 3:1.
Claim 4
Dependent Claim
25 words
The composite article according to claim 1 wherein the weight ratio of total particles to fibril matrix is in the range of 98:2 to 75:25.
Claim 5
Dependent Claim
18 words
The composite article according to claim 1 wherein said conductive particles are metal particles or metal coated particles.
Claim 6
Dependent Claim
20 words
The composite article according to claim 4 wherein said metal or metal-coated particles are powder, flakes, bubbles, fibers, or beads.
Claim 7
Dependent Claim
18 words
The composite article according to claim 1 wherein said article has a resistivity of less than 50 ohm-cm.
Claim 8
Dependent Claim
71 words
An electrically conductive composite article comprising a polytetrafluoroethylene fibril matrix having enmeshed therein (a) electrically conductive metal-containing particles, and (b) electrically nonconductive, energy expandable hollow polymeric particles having a polymeric shell and a liquid or gaseous core said composite article having a resistivity of less than about 1000 Ω.cm prior to expansion of said energy expandable particles and greater than about 10 5 Ω.cm after expansion of said energy expandable particles.
Claim 9
Dependent Claim
71 words
An electrically conductive composite article comprising a polytetrafluoroethylene fibril matrix having enmeshed therein (a) electrically conductive metal-containing particles, and (b) electrically nonconductive, energy expandable hollow polymeric particles having a polymeric shell and a liquid or gaseous core said composite article having a resistivity of less than about 1000 Ω.cm prior to expansion of said energy expandable particles and greater than about 10 5 Ω.cm after expansion of said energy expandable particles.
Claim 10
Dependent Claim
55 words
The composite article according to claim 7 wherein said nonconductive expandable particles have shells comprising copolymers selected from the group consisting of vinyl chloride and vinylidene chloride, vinyl chloride and acrylonitrile, vinylidene chloride and acrylonitrile, styrene and acrylonitrile, methyl methacrylate and styrene, methyl methacrylate and ethyl methacrylate, methacrylonitrile and acrylonitrile, and methyl methacrylate and orthochlorostyrene.
Claim 11
Dependent Claim
22 words
The composite article according to claim 1 wherein said conductive particles have a size in the range of 0.1 to 600 micrometers.
Claim 12
Dependent Claim
24 words
The composite article according to claim 1 wherein said nonconductive expandable particles expand at a temperature in the range of 40° to 220° C.
Claim 13
Dependent Claim
18 words
The composite article according to claim 7 wherein said shell of said nonconductive expandable particles are poly(vinylidene chloride-co-acrylonitrile).
Claim 14
Dependent Claim
17 words
The composite article according to claim 7 wherein said shell of said nonconductive expandable particles is poly(methacrylonitrile-co-acrylonitrile).
Claim 15
Dependent Claim
23 words
The composite article according to claim 1 which is a membrane having a thickness in the range of 0.010 cm to 0.32 cm.
Claim 16
Dependent Claim
42 words
The composite article according to claim 1 wherein said composite article has a resistivity of less than about 100 Ω.cm prior to expansion of said energy expandable particles and greater than about 10 6 Ω.cm after expansion of said energy expandable particles.
Claim 17
Dependent Claim
43 words
The composite article according to claim 1 wherein said composite article has a resistivity of less than about 50 ≠. cm prior to expansion of said energy expandable particles and greater than about 10 7 Ω.cm after expansion of said energy expandable particles.
Claim 18
Dependent Claim
59 words
An irreversible fuse element comprising a polytetrafluoroethylene fibril matrix, having enmeshed therein a) electrically conductive particles, and b) electrically nonconductive, energy expandable hollow polymeric particles said composite article having a resistivity of less than about 1000 Ω.cm prior to expansion of said energy expandable particles and greater than about 10 5 Ω.cm after expansion of said energy expandable particles.
Claim 19
Dependent Claim
59 words
An irreversible fuse element comprising a polytetrafluoroethylene fibril matrix, having enmeshed therein a) electrically conductive particles, and b) electrically nonconductive, energy expandable hollow polymeric particles said composite article having a resistivity of less than about 1000 Ω.cm prior to expansion of said energy expandable particles and greater than about 10 5 Ω.cm after expansion of said energy expandable particles.
Claim 20
Dependent Claim
32 words
The fuse element according to claim 14 wherein said electrically conductive particles are selected from the group consisting of carbon, metal, and particles coated with at least one of carbon and metal.
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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) | 1997-07-11 | 1998-01-10 | 1998-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-07-11 | 2002-01-10 | 2002-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-07-11 | 2006-01-10 | 2006-07-12 | $7700.00 | Window Closed / Lapsed |