Patent US3177181A successfully refreshed from Google Patents.
US3177181A
Expired / Lapsed
US
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Two stage vacuum devolatilization to purify polyamides
Assignee: Foster Grant Co Inc
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Filing: 1960-11-14
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Granted: 1965-04-06
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Expires: 1980-11-14
Abstract
No abstract record available.
Inventors
- 👤 Sidney J Baum
- 👤 Aelion Rene
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:51
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/46
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
110 words
A METHOD OF POLYMER PURIFICATION WHEREIN UNPOLYMERIZED MONOMER AND VOLATILIZABLE LOW MOLECULAR WEIGHT OLIGOMERS ARE REMOVED FROM A POLY(AMINOCARBOXYLIC ACID)-TYPE POLYAMIDE REACTION PRODUCT, SAID METHOD COMPRISING: FEEDING SAID POLYAMIDE REACTION PRODUCT THROUGH AN EXTRUSION ZONE IN A MOLTEN STATE AT A TEMPERATURE IN THE RANGE FROM ABOUT 200*C. TO ABOUT 300*C.; EXTRACTING AT LEAST A PREDOMINANT PORTION OF THE MONOMER BY FEEDING THE MOLTEN POLYMERS PAST A FIRST VENTING PASSAGE IN THE EXTRUSTION ZONE, SAID PASSAGE BEING MAINTAINED AT A SUBATMOSPHERIC PRESSURE OF FROM ABOUT 2 TO ABOUT 40 MILLIMETERS OF MERCURY; MAINTAINING SAID PREDOMINANT PORTION OF THE EXTRACTED MONOMER AT A TEMPERATURE OF FROM ABOUT 70*C. TO ABOUT 100*C.;
Claim 2
Independent Claim
110 words
A METHOD OF POLYMER PURIFICATION WHEREIN UNPOLYMERIZED MONOMER AND VOLATILIZABLE LOW MOLECULAR WEIGHT OLIGOMERS ARE REMOVED FROM A POLY(AMINOCARBOXYLIC ACID)-TYPE POLYAMIDE REACTION PRODUCT, SAID METHOD COMPRISING: FEEDING SAID POLYAMIDE REACTION PRODUCT THROUGH AN EXTRUSION ZONE IN A MOLTEN STATE AT A TEMPERATURE IN THE RANGE FROM ABOUT 200*C. TO ABOUT 300*C.; EXTRACTING AT LEAST A PREDOMINANT PORTION OF THE MONOMER BY FEEDING THE MOLTEN POLYMERS PAST A FIRST VENTING PASSAGE IN THE EXTRUSTION ZONE, SAID PASSAGE BEING MAINTAINED AT A SUBATMOSPHERIC PRESSURE OF FROM ABOUT 2 TO ABOUT 40 MILLIMETERS OF MERCURY; MAINTAINING SAID PREDOMINANT PORTION OF THE EXTRACTED MONOMER AT A TEMPERATURE OF FROM ABOUT 70*C. TO ABOUT 100*C.;
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-04-05 | 1968-10-05 | 1969-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-04-05 | 1972-10-05 | 1973-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-04-05 | 1976-10-05 | 1977-04-06 | $7700.00 | Window Closed / Lapsed |