Patent US3707431A successfully refreshed from Google Patents.
US3707431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Film structure having undulating surface
Assignee: EIDP Inc
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Filing: 1971-01-19
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Granted: 1972-12-26
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Expires: 1991-01-19
Abstract
Abstract A THERMOPLASTIC FILM ORIENTED BY BIAXIAL STRETCHING HAVING A NOMINAL THICKNESS OF 5 MILS OR LESS AND TRANSVERSEY REPEATNG UNDULATIONS THAT FORM RIDGES AND VALLEYS EXTENDING LONGITUDINALLY ALONG THE LENGTH OF THE FILM WHEREIN THE RATIO OF THE WAVELENGTH TO AMPLITUDE OF THE UNDULATIONS IS ABOUT 500-2000:1 AND THE AMPLITUDE IS NOT GREATER THAN ABOUT 10% OF THE THICKNESS OF THE FILM. THESE FILMS HAVE SIGNIFICANTLY IMPROVED WINDING CHARACTERISTICS AND ARE PARTICULARLY USEFUL AS A BASE FILM FOR MANUFACTURING MAGNETIC RECORDING TAPES.
Inventors
- 👤 Harold Barnard Whitfield Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:40
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/74; G11B5/78; B; B29; B29C; B29C55/00; B29C55/02; B29C55/10; B29C55/12; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24628; Y10T428/24669; Y10T428/24694; Y10T428/26
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-26 | 1976-06-26 | 1976-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-26 | 1980-06-26 | 1980-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-26 | 1984-06-26 | 1984-12-26 | $7700.00 | Window Closed / Lapsed |