US3634356A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state polymerization of polyester filaments
Assignee: FMC Corp
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Filing: 1969-05-02
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Granted: 1972-01-11
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Expires: 1989-05-02
Abstract
Abstract A PROCESS OF INCREASING THE MOLECULAR WEIGHT OF A LOW MOLECULAR WEIGHT POLYESTER COMPRISING FORMING SAID LOW MOLECULAR WEIGHT POLYESTER INTO SOLID FILAMENTS AND THEN EXPOSING SAID FILAMENTS TO A FLOWING STREAM OF A HOT INERT GAS, MAINTAINING THE TEMPERATURE BELOW THE MELTING POINT OF SAID FILAMENTS, FOR SUCH A TIME UNTIL THE POLYESTER HAS AN INTRINSIC VISCOSITY OF AT LEAST 0.60.
Inventors
- 👤 Sager Tryon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:26
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/80
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) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |