US4259281A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for reducing micro-voids in the extruded insulation of electric cables
Assignee: Pirelli and C SpA
•
Filing: 1979-04-17
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Granted: 1981-03-31
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Expires: 1999-04-17
Abstract
Abstract A process for reducing micro-voids in cross-linked cable insulation without reducing the voltage breakdown strength thereof in which process the insulation, after cross-linking, is heated at a temperature in the range from about 120° C. to about 150° C. and under a pressure less than 10 mm. Hg for a period from about 8 hours to 48 hours. Also, a cable having such insulation which has micro-voids less than about 10 2 per mm 3 and a perforation gradient greater than the perforation gradient of a cable which has not been so treated.
Inventors
- 👤 Gianmario Lanfranconi
- 👤 Bernardino Vecellio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:38
CPC Classifications
H; H01; H01B; H01B13/00; H01B13/06; H01B13/14; H01B13/145; C; C08; C08J; C08J7/00; C08J7/08; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
67 words
A process for reducing the micro-voids in cross-linked polyethylene insulation around an electric cable conductor and for increasing the perforation gradient thereof, said process comprising heating the so cross-linked insulation at a temperature from about 120° to 150° C. and in an ambient having a pressure less than 10 mm. Hg for a time sufficient to significantly reduce the number of said micro-voids per mm 3 .
Claim 2
Dependent Claim
67 words
A process for reducing the micro-voids in cross-linked polyethylene insulation around an electric cable conductor and for increasing the perforation gradient thereof, said process comprising heating the so cross-linked insulation at a temperature from about 120° to 150° C. and in an ambient having a pressure less than 10 mm. Hg for a time sufficient to significantly reduce the number of said micro-voids per mm 3 .
Claim 3
Dependent Claim
27 words
A process as set forth in claim 1 wherein said insulation is heated at said temperature and at said pressure for about eight to about forty-eight hours.
Claim 4
Dependent Claim
37 words
A process as set forth in claim 1 or 2 wherein said insulation is cross-linked by incorporating a cross-linking agent therein and by subjecting it to saturated steam at a pressure at least several times atmospheric pressure.
Claim 5
Dependent Claim
14 words
A process as set forth in claim 3 wherein said cross-linking agent is dicumylperoxide.
Claim 6
Dependent Claim
33 words
A process as set forth in claim 1 wherein said insulation is cross-linked by incorporating a cross-linking agent therein and by subjecting it to heat and pressure without the penetration of moisture therein.
Claim 7
Dependent Claim
14 words
A process as set forth in claim 5 wherein said cross-linking agent is dicumylperoxide.
Claim 8
Dependent Claim
39 words
A process as set forth in claim 1 wherein said insulation is heated at said temperature and at said pressure for a time sufficient to reduce the number of micro-voids to less than 10 3 per mm 3 .
References Cited (Backward Citations)
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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) | 1984-03-30 | 1984-09-29 | 1985-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-30 | 1988-09-29 | 1989-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-30 | 1992-09-29 | 1993-03-31 | $7700.00 | Window Closed / Lapsed |