US3717522A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming a cross-linked polyethylene insulator
Assignee: SWCC Corp
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Filing: 1969-07-25
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Granted: 1973-02-20
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Expires: 1989-07-25
Abstract
Abstract A cross-linked polyethylene insulation having good electrical characteristics can be obtained by laminatedly wrapping of solid phase polyethylene film containing a small amount of substantially involatile hydrocarbon insulating oil and di- Alpha -cumyl peroxide round a solid article and then heating the wrapped article. The present method is suitable as a method for forming a thick cross-linked polyethylene insulation on large size conductor or forming a joint section of cross-linked polyethylene cable.
Inventors
- 👤 A Shirato
- 👤 H Furuyama
- 👤 M Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:52
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/441
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
161 words
A method for forming a cross-linked polyethylene insulation, which comprises immersing a solid phase polyethylene film having a thickness of 0.05 to 0.5 mm and containing 60 percent by weight of polyethylene soluble in xylene at 80*C. in a solution of substantially involatile hydrocarbon insulating oil containing at least 10 percent by weight of dissolved di- Alpha -cumyl peroxide, impregnating the film with the solution until the film contains 0.5 to 5.0 percent by weight of the insulating oil and 0.5 to 5.0 percent by weight of the peroxide,; laminatedly wrapping the impregnated film around a solid article under a tension of 0.2 to 1.2 kg/mm2 applied to the film to form a plurality of film interlayers; and then heating the wrapped article at a temperature of 110* to 180*C. to fuse said film interlayers into an integral insulating layer and to cross-link the polyethylene until at least 70 percent by weight of the polyethylene becomes insoluble in xylene at 80*C.
Claim 2
Independent Claim
161 words
A method for forming a cross-linked polyethylene insulation, which comprises immersing a solid phase polyethylene film having a thickness of 0.05 to 0.5 mm and containing 60 percent by weight of polyethylene soluble in xylene at 80*C. in a solution of substantially involatile hydrocarbon insulating oil containing at least 10 percent by weight of dissolved di- Alpha -cumyl peroxide, impregnating the film with the solution until the film contains 0.5 to 5.0 percent by weight of the insulating oil and 0.5 to 5.0 percent by weight of the peroxide,; laminatedly wrapping the impregnated film around a solid article under a tension of 0.2 to 1.2 kg/mm2 applied to the film to form a plurality of film interlayers; and then heating the wrapped article at a temperature of 110* to 180*C. to fuse said film interlayers into an integral insulating layer and to cross-link the polyethylene until at least 70 percent by weight of the polyethylene becomes insoluble in xylene at 80*C.
Claim 3
Dependent Claim
14 words
The method of claim 1 in which said solid article is an electrical conductor.
Claim 4
Dependent Claim
20 words
The method of claim 1 in which said involatile hydrocarbon insulating oil fills very fine voids formed between said layers.
Claim 5
Independent Claim
226 words
A method for forming a cross-linked polyethylene insulation, which comprises immersing a solid phase polyethylene film havIng a thickness of 0.05 to 0.5 mm that is substantially completely soluble in xylene at 80*C. in a solution of substantially involatile hydrocarbon insulating oil containing at least 10 percent by weight of di- Alpha -cumyl peroxide and at least 10 percent by weight of a peroxide for cross-linking polyethylene having a decomposition temperature lower than 110*C.; impregnating the film with said solution until the film contains 0.5 to 5.0 percent by weight of the insulating oil, 0.5 to 5.0 percent by weight of di- Alpha -cumyl peroxide and 0.5 to 5.0 percent by weight of the peroxide having a decomposition temperature lower than 110*C.; heating the impregnated film at a temperature lower than 110*C. until 3 to 40 percent by weight of the polyethylene in said film becomes insoluble in xylene at 80*C.; laminatedly wrapping the resulting partially cross-linked film around a solid article under a tension of 0.2 to 1.2 kg/mm2 applied to the film to form a plurality of film interlayers; and then heating the wrapped article at a temperature of 110* to 180*C. to weld the film interlayers into an integral insulating layer and to cross-link the polyethylene further until at least 70 percent by weight of the polyethylene becomes insoluble in xylene at 80*C.
Claim 6
Independent Claim
226 words
A method for forming a cross-linked polyethylene insulation, which comprises immersing a solid phase polyethylene film havIng a thickness of 0.05 to 0.5 mm that is substantially completely soluble in xylene at 80*C. in a solution of substantially involatile hydrocarbon insulating oil containing at least 10 percent by weight of di- Alpha -cumyl peroxide and at least 10 percent by weight of a peroxide for cross-linking polyethylene having a decomposition temperature lower than 110*C.; impregnating the film with said solution until the film contains 0.5 to 5.0 percent by weight of the insulating oil, 0.5 to 5.0 percent by weight of di- Alpha -cumyl peroxide and 0.5 to 5.0 percent by weight of the peroxide having a decomposition temperature lower than 110*C.; heating the impregnated film at a temperature lower than 110*C. until 3 to 40 percent by weight of the polyethylene in said film becomes insoluble in xylene at 80*C.; laminatedly wrapping the resulting partially cross-linked film around a solid article under a tension of 0.2 to 1.2 kg/mm2 applied to the film to form a plurality of film interlayers; and then heating the wrapped article at a temperature of 110* to 180*C. to weld the film interlayers into an integral insulating layer and to cross-link the polyethylene further until at least 70 percent by weight of the polyethylene becomes insoluble in xylene at 80*C.
Claim 7
Dependent Claim
31 words
The method of claim 4 in which the peroxide for cross-linking polyethylene having a decomposition temperature below 110*C is selected from the group consisting of tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyisobutyrate, and 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.
Claim 8
Dependent Claim
14 words
The method of claim 4, in which said solid article is an electrical conductor.
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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |