Patent US4659871A successfully refreshed from Google Patents.
US4659871A
Expired / Lapsed
US
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Cable with flame retarded cladding
Assignee: Raychem Ltd
•
Filing: 1986-06-24
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Granted: 1987-04-21
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Expires: 2006-06-24
Abstract
Abstract Polymeric cladding for elongate substrates, preferably electrical conductors, comprises an inner layer and an outer layer, the outer layer being a cross-linked polymer composition filled with halogen-free particulate inorganic flame-retardant filler which has been treated with material which increases the elongation to break of the composition at 200 DEG C. to at least 50%. The enhanced elongation enables the cladding better to resist burning, possibly by reducing the tendency for the outer layer to split when exposed to fire. Bundles of insulated electrical wires may be wrapped in mineral tape, preferably mica tape, to provide circuit integrity cables which are significantly smaller and/or lighter than previously known.
Inventors
- 👤 Timothy S. Smith
- 👤 Richard J. Murphy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:29
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/42; C; C08; C08K; C08K9/00; C08K9/04; H01B3/303; H01B3/44; H01B3/441; H01B7/00; H01B7/17; H01B7/29; H01B7/295; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/294; Y10T428/2958
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
135 words
A multiconductor electric cable which comprises: (a) a bundle of electrical conductors each of which is electrically insulated from each other conductor by means only of an insulating coating of an organic polymeric material that is extruded onto the individual conductors; (b) a mineral tape wrapped around the bundle of electrical conductors; and (c) an outer cable jacket; wherein each insulating coating has a thickness in the range of from 0.1 to 0.4 mm and comprises an inner layer and an outer layer, the inner layer having a volume resistivity of at least 10 10 ohm cm and the outer layer including an inorganic flame retardant filler that causes the insulating coating to leave an electrically insulating residue on combustion and will prevent shorting of the conductors when maintained at 800° C. for 90 minutes.
Claim 2
Dependent Claim
135 words
A multiconductor electric cable which comprises: (a) a bundle of electrical conductors each of which is electrically insulated from each other conductor by means only of an insulating coating of an organic polymeric material that is extruded onto the individual conductors; (b) a mineral tape wrapped around the bundle of electrical conductors; and (c) an outer cable jacket; wherein each insulating coating has a thickness in the range of from 0.1 to 0.4 mm and comprises an inner layer and an outer layer, the inner layer having a volume resistivity of at least 10 10 ohm cm and the outer layer including an inorganic flame retardant filler that causes the insulating coating to leave an electrically insulating residue on combustion and will prevent shorting of the conductors when maintained at 800° C. for 90 minutes.
Claim 3
Dependent Claim
22 words
A cable as claimed in claim 1, wherein the filler is selected from the group consisting of hydrated metal oxides and silica.
Claim 4
Dependent Claim
13 words
A cable as claimed in claim 1, wherein the filler comprises hydrated alumina.
Claim 5
Dependent Claim
18 words
A cable as claimed in claim 1, wherein the organic polymeric material comprises an alkene homo- or copolymer.
Claim 6
Dependent Claim
18 words
A cable as claimed in claim 4, wherein the organic polymeric material comprises polyethylene or an ethylene/propylene copolymer.
Claim 7
Dependent Claim
31 words
A cable as claimed in claim 1, wherein the quantity of filler in the outer layer is at least 60% by weight based on the total weight of the outer layer.
Claim 8
Dependent Claim
54 words
A cable as claimed in claim 1, wherein the material forming the outer layer is cross-linked and the filler of the outer layer has been treated with a treatment material that will increase the elongation to break of the material forming the outer layer at 200° C. to a value of at least 50%.
Claim 9
Dependent Claim
18 words
A cable as claimed in claim 1, wherein the insulating coating of each conductor is substantially halogen free.
Claim 10
Dependent Claim
13 words
A cable as claimed in claim 1, wherein each mineral tape contains mica.
Claim 11
Dependent Claim
15 words
A cable as claimed in claim 1, wherein the cable jacket is substantially halogen free.
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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) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |