US4551499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymeric dielectrics
Assignee: STC PLC
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Filing: 1984-08-08
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Granted: 1985-11-05
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Expires: 2004-08-08
Abstract
Abstract A nucleating agent comprising either a substantially non-polar wax or an inert inorganic finely divided powder is incorporated in a thermoplastics polymer, e.g. polyethylene. Thus reduces the spherulite size of the material and thus increases its breakdown field strength.
Inventors
- 👤 Brian A. Cranfield
- 👤 John C. Fothergill
- 👤 Susan V. Wolfe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:38
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/441; C; C08; C08K; C08K3/00; C08K3/34; C08K3/36
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
67 words
A thermoplastic polymer dielectric selected from the group consisting of polyethylene and polypropylene and having incorporated therein a nucleating agent, said nucleating agent comprising ceresin wax having an average particulate diameter of less than one micron, said nucleating agent being incorporated in an amount of about 0.01-5 weight percent whereby the average polymer spherulite size is reduced and the breakdown field strength of the polymer is increased.
Claim 2
Dependent Claim
67 words
A thermoplastic polymer dielectric selected from the group consisting of polyethylene and polypropylene and having incorporated therein a nucleating agent, said nucleating agent comprising ceresin wax having an average particulate diameter of less than one micron, said nucleating agent being incorporated in an amount of about 0.01-5 weight percent whereby the average polymer spherulite size is reduced and the breakdown field strength of the polymer is increased.
Claim 3
Dependent Claim
19 words
The polymer dielectric of claim 1 wherein the average spherulite diameter is in a range of about 25-30 microns.
Claim 4
Dependent Claim
13 words
An electrical cable or wire product utilizing the polymer dielectric of claim 1.
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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) | 1988-11-04 | 1989-05-06 | 1989-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-04 | 1993-05-06 | 1993-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-04 | 1997-05-06 | 1997-11-05 | $7700.00 | Window Closed / Lapsed |