Patent US3775549A successfully refreshed from Google Patents.
US3775549A
Expired / Lapsed
US
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Electrically insulating polyproplyene laminate paper and oil-impregnated electric power cable using said laminate paper
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1972-06-23
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Granted: 1973-11-27
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Expires: 1992-06-23
Abstract
Abstract An insulation for electric cables which comprises a biaxially oriented polypropylene film bonded to an oil-impregnated paper by means of a melt-extruded polyolefin adhesive and the resulting insulated cable are disclosed.
Inventors
- 👤 S Matsuda
- 👤 H Kuwabara
- 👤 H Kubo
- 👤 Y Sasajima
- 👤 K Suzuki
- 👤 T Fukamachi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:21
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/10; H; H01; H01B; H01B3/00; H01B3/18; H01B3/48; H01B3/485; B32B27/32; B32B38/00; B32B38/08; B32B38/16; B32B38/164; B32B7/00; B32B7/04; B32B7/12; H01B13/00; H01B13/30; B32B2260/00; B32B2260/04; B32B2307/00; B32B2307/20; B32B2307/206; B32B2307/50; B32B2307/514; B32B2307/518; B32B2307/70; B32B2307/724; B32B2307/7242; B32B2307/7244; B32B2309/00; B32B2309/08; B32B2309/10; B32B2309/105; B32B2317/00; B32B2317/12; B32B2323/00; B32B2323/10; B32B2457/00; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/3188; Y10T428/31895
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
13 words
The laminate of claim 1 wherein said polyolefin adhesive is an unoriented polyolefin.
Claim 2
Dependent Claim
13 words
winding the moisture-containing polypropylene-paper laminate around said conductor while said laminate is wet;
Claim 3
Dependent Claim
6 words
drying to remove the moisture; and
Claim 4
Dependent Claim
19 words
The laminate of claim 2 wherein the air-impermeability of said electrically insulating paper is at least 200 Gurley seconds.
Claim 5
Dependent Claim
21 words
The laminate of claim 3 wherein the thickness of said biaxially oriented polypropylene film is not more than 100 Mu m.
Claim 6
Dependent Claim
6 words
impregnating said laminate with said oil.
Claim 7
Dependent Claim
25 words
The laminate of claim 3 wherein the thickness of said polyolefin adhesive is not more than 0.75 times the thickness of said electrically insulating paper.
Claim 8
Dependent Claim
102 words
An oil-impregnated electric power cable comprising an electrical conductor and insulation surrounding said conductor, at least a portion of said insulation comprising an electrically insulating polypropylene-paper laminate consisting of an integrated assembly selected from the group consisting of polypropylene and a propylene copolymer containing a major proportion of propylene units, the thickness of said adhesive being less than the thicknesses of each of said paper and said film and being as small as possible without substantially sacrificing the bond strength exhibited between said electrically insulating paper and said polypropylene film, said electrically insulating polypropylene-paper laminate having an electrically insulAting oil impregnated therein.
Claim 9
Dependent Claim
43 words
The electric power cable of claim 14 wherein said electrically insulating polypropylene-paper laminate is wound around said conductor with the paper side of said laminate facing the conductor and wherein said electrically insulating paper has an air-impermeability of at least 200 Gurley seconds.
Claim 10
Dependent Claim
44 words
The electric power cable of claim 7 wherein the thickness of said biaxially oriented polypropylene film is not more than 100 Mu m and wherein the thickness of said polyolefin adhesive is not more than 0.75 times the thickness of said electrically insulating paper.
Claim 11
Dependent Claim
15 words
The electric power cable of claim 7 wherein said polyolefin adhesive comprises an unoriented polyolefin.
Claim 12
Dependent Claim
40 words
The electric power cable of claim 7 wherein the ratio of the dielectric constant ( epsilon ) of said electrically insulating polypropylene-paper laminate to the dielectric constant ( epsilon ) of said electrically insulating oil varies from 1 to 1.5.
Claim 13
Dependent Claim
19 words
The electric power cable of claim 7 wherein the dielectric loss tangent thereof is not more than 0.5 percent.
Claim 14
Dependent Claim
12 words
The process for producing the electric power cable of claim 15 comprising:
References Cited (Backward Citations)
US3497574A
Cited
US3194872A
Cited
US3380868A
Cited
US3370106A
Cited
US3450968A
Cited
US3542717A
Cited
US3634546A
Cited
US3607987A
Cited
US3671383A
Cited
US3560227A
Cited
US3594489A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |