Patent US3316620A successfully refreshed from Google Patents.
US3316620A
Expired / Lapsed
US
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Process for the production of electrets
Assignee: Philip Morris USA Inc
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Filing: 1964-02-28
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Granted: 1967-05-02
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Expires: 1984-02-28
Abstract
No abstract record available.
Inventors
- 👤 Jr Lawrence Lee Stewart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:02
CPC Classifications
H; H01; H01G; H01G7/00; H01G7/02; H01G7/021; H01G7/023; Y; Y10; Y10T; Y10T29/00; Y10T29/43; Y10T29/435; Y10T29/49; Y10T29/49002; Y10T29/49226
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
75 words
A PROCESS FOR THE PRODUCTION OF ELECTRETS WHICH COMPRISES WRAPPING AT LEAST ONE LAYER OF AN INSULATED ELECTRETFORMING MATERIAL AROUND AN ELECTRICALLY CONDUCTING CORE, PLACING AN ELECTRICALLY CONDUCTING SHEATH AROUND SAID ELECTRET-FORMING MATERIAL, HEATING THE ASSEMBLY TO A PREDETERMINED TEMPERATURE FOR A PREDETERMINED TIME, APPLYING A DIRECT CURRENT ELECTRICAL FIELD BETWEEN SAID CORE AND SAID SHEATH, AND SEPARATING SAID ELECTRET-FORMING MATERIAL FROM SAID CORE AND SAID SHEATH AFTER TERMINATION OF SAID HEAT AND FIELD APPLICATIONS.
Claim 2
Dependent Claim
75 words
A PROCESS FOR THE PRODUCTION OF ELECTRETS WHICH COMPRISES WRAPPING AT LEAST ONE LAYER OF AN INSULATED ELECTRETFORMING MATERIAL AROUND AN ELECTRICALLY CONDUCTING CORE, PLACING AN ELECTRICALLY CONDUCTING SHEATH AROUND SAID ELECTRET-FORMING MATERIAL, HEATING THE ASSEMBLY TO A PREDETERMINED TEMPERATURE FOR A PREDETERMINED TIME, APPLYING A DIRECT CURRENT ELECTRICAL FIELD BETWEEN SAID CORE AND SAID SHEATH, AND SEPARATING SAID ELECTRET-FORMING MATERIAL FROM SAID CORE AND SAID SHEATH AFTER TERMINATION OF SAID HEAT AND FIELD APPLICATIONS.
References Cited (Backward Citations)
US2785350A
Cited
US2842653A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1970-05-01 | 1970-10-31 | 1971-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-05-01 | 1974-10-31 | 1975-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-05-01 | 1978-10-31 | 1979-05-02 | $7700.00 | Window Closed / Lapsed |