US3702357A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Uniformity of polyester films
Assignee: Eastman Kodak Co
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Filing: 1971-06-25
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Granted: 1972-11-07
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Expires: 1991-06-25
Abstract
Abstract CONVENTIONALLY HEAT-SET, BIAXIALLY ORIENTED POLYESTER FILMS SUCH AS POLY(ETHYLENE TEREPHTHALATE) GENERALLY HAVE NON-UNIFORM PHYSICAL PROPERTIES ACROSS THE WIDTH OF THE FILM. IT HAS BEEN DISCOVERED THAT THE RELATIVE UNIFORMITY OF SUCH PROPERTIES ACROSS THE WIDTH OF THE FILM CAN BE SIGNIFICANTLY INCREASED BY STRETCHING THE FILM IN THE TRANSVERSE DIRECTION (DURING THE TENTERING STEP) WHILE THE SURFACES OF THE FILM ARE MAINTAINED AT A SUBSTANTIALLY UNIFORM TEMPERATURE OF AT LEAST ABOUT 260*F., WHICH IS HIGHER THAN WAS HERETOFORE BELIEVED PRACTICAL IN A TENTERING OPERATION.
Inventors
- 👤 Edward W Smith Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:35
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/02; B29C55/10; B29C55/12; B29C55/14; B29C55/143; B29C71/00; B29K; B29K2067/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1975-11-07 | 1976-05-08 | 1976-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-07 | 1980-05-08 | 1980-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-07 | 1984-05-08 | 1984-11-07 | $7700.00 | Window Closed / Lapsed |