US4547328A
Expired / Lapsed
US
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Method for producing foamed plastic insulator
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1984-04-16
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Granted: 1985-10-15
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Expires: 2004-04-16
Abstract
Abstract A foamed plastic insulator such as an insulated wire having a foamed plastic material insulation layer formed over a conductor. The plastic material includes at least one component having a swelling ratio greater than 55%, and the component comprises at least 20% by weight of the insulation layer. The insulated wire is produced by adding a blowing agent such as a chemical blowing agent and an inert gas and extruding the mixture over a conductor.
Inventors
- 👤 Masao Yuto
- 👤 Yoichi Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:43
CPC Classifications
H; H01; H01B; H01B13/00; H01B13/06; H01B13/14; B; B29; B29C; B29C44/00; B29C44/20; B29C44/32; B29C44/322; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/441; H01B7/00; H01B7/17; H01B7/28; H01B7/282; H01B7/285; H01B7/2855; Y; Y02; Y02A; Y02A30/00; Y02A30/14; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/13
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
65 words
A method for producing a foamed plastic insulator comprising the steps of: preparing a plastic material comprising low density polyethylene having a melt flow swelling ratio of at least 55% adding a chemical and/or inert gas blowing agent to said plastic material, extruding a mixture of said plastic material and said blowing agent over a conductor, and foaming said mixture to produce foamed insulation layer.
Claim 2
Independent Claim
65 words
A method for producing a foamed plastic insulator comprising the steps of: preparing a plastic material comprising low density polyethylene having a melt flow swelling ratio of at least 55% adding a chemical and/or inert gas blowing agent to said plastic material, extruding a mixture of said plastic material and said blowing agent over a conductor, and foaming said mixture to produce foamed insulation layer.
Claim 3
Dependent Claim
30 words
The method of claim 1 further comprising the step of extruding a second plastic material over said mixture simultaneously with the extrusion of said mixture to form a solid layer.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein said blowing agent is a chemical blowing agent selected from the group consisting of azodicarbonamide, 4,4'-oxybis(bensenesulfonylhydrazide).
Claim 5
Dependent Claim
36 words
The method of claim 3, wherein said mixture of at least two kinds of polyolefins consists essentially of at least 20 weight percent of low density polyethylene whose melt flow swelling ratio is greater than 55%.
Claim 6
Dependent Claim
11 words
The method of claim 2, wherein said solid layer is polyolefin.
Claim 7
Dependent Claim
22 words
The method of claim 1 wherein said blowing agent is a chemical blowing agent selected from the group consisting of azodicarbonamide, 4,4'-oxybis(bensenesulfonylhydrazide).
Claim 8
Dependent Claim
27 words
The method of claim 1 wherein said blowing agent is an inert gas blowing agent selected from the group consisting of nitrogen, argon, and carbonic acid gases.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |