US3890283A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for post-polymerizing polyglycolic acid
Assignee: Wyeth Holdings LLC
•
Filing: 1973-06-04
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Granted: 1975-06-17
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Expires: 1993-06-04
Abstract
Abstract A process for producing ultra high molecular weight polyglycolic acid comprising subjecting polyglycolic acid of conventional molecular weight to a prolonged heat treatment under vacuum.
Inventors
- 👤 Donald James Casey
- 👤 Martin Epstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:22
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/02; C08G63/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
50 words
A PROCESS FOR INCREASING THE MOLECULAR WEIGHT OF POLYGLYCOLIC ACID COMPRISING HEATING SAID POLYGLYCOLIC ACIDS IN A SOLID STATE AT A TEMPERATURE BETWEEN ABOUT 150*C. AND 220*C. FOR A PERIOD OF TIME OF AT LEAST 4 DAYS AT AN ABSOLUTE PRESSURE BETWEEN ABOUT 0.1 MM. AND 1.0 MM. OF MERCURY.
Claim 2
Dependent Claim
50 words
A PROCESS FOR INCREASING THE MOLECULAR WEIGHT OF POLYGLYCOLIC ACID COMPRISING HEATING SAID POLYGLYCOLIC ACIDS IN A SOLID STATE AT A TEMPERATURE BETWEEN ABOUT 150*C. AND 220*C. FOR A PERIOD OF TIME OF AT LEAST 4 DAYS AT AN ABSOLUTE PRESSURE BETWEEN ABOUT 0.1 MM. AND 1.0 MM. OF MERCURY.
Claim 3
Dependent Claim
15 words
A process according to claim 1 in which the polyglycolic acid is in pellet form.
Claim 4
Dependent Claim
17 words
The process according to claim 1 in which the temperature is maintained at about 190* to 200*C.
Claim 5
Dependent Claim
15 words
The process according to claim 3 in which the polyglycolic acid is in pellet form.
Claim 6
Dependent Claim
48 words
The process according to claim 1 in which the polyglycolic acid being heated contains as a molecular weight regulator a reactive content or chemically combined content of from about 0.05 to about 1.5 mole percent of an alcohol devoid of any reactive groups other than alcoholic hydroxy groups.
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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) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |