US3663670A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plug flow method for molding foamed polylactams
Assignee: EIDP Inc
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Filing: 1967-06-20
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Granted: 1972-05-16
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Expires: 1987-06-20
Abstract
Abstract FOAMED EXPANDED POLYLACTAMS ARE PREPARED BY ANIONICALLY POLYMERIZING LACTAM IN A MOLD CAVITY IN THE PRESENCE OF FOAMING AGENT UNDER PRESSURE SUFFICIENT TO MAINTAIN FOAMING AGENT IN THE LACTAM, I.E., MONOMERIC LACTAM OR POLYLACTAM. THEN, AFTER POLYMERIZATION IS SUBSTANTIALLY COMPLETE, PRESSURE ON THE POLYACTAM IS REDUCED BY OPENING AN EXIT PORT AND EJECTING THE SHAPED SOLID POLYLACTAM OUT OF THE MOLD CAVITY INTO AN AREA OF LOWER PRESSURE THUS PRODUCING CELLULAR POLYACTAM OF LOW DENSITY AND HIGH TENSILE STRENGTH.
Inventors
- 👤 Kenneth G Swayne
- 👤 Henry L Dragun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:09
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J2377/00; C08J2377/02; Y; Y10; Y10S; Y10S264/00; Y10S264/14
Claims Analysis
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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) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |