Patent US3784540A successfully refreshed from Google Patents.
US3784540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of preparing soluble hema-based polymers
Assignee: National Patent Development Corp
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Filing: 1971-10-05
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Granted: 1974-01-08
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Expires: 1991-10-05
Abstract
Abstract SOLVENT SOLUBLE SOLID HYDROPHILIC POLYMERS AND COPOLYMERS OF HYDROXYETHYL METHACRYLATE AND OTHER HYDROXYALKYL ACRYLATES AND METHACRYLATES ARE PREPARED BY POLYMERIZING THE MONOMER IN AN ORGANIC SOLVENT OR DILUENT FOR THE MONOMER WHICH IS A NON-SOLVENT FOR THE POLYMER HAVING A COEFFICIENT OF SWELLING OF NOT OER 2, PREFERABLY NOT OVER ABOUT 1.5 AND A TEMPERATURE OF PRECIPITATION OF 0 OR ABOVE, PREFERABLY 30* C. OR ABOVE WHILE MAINTAINING THE SOLIDS CONENT IN SOLUTION BELOW THAT AT WHICH THE POLYMER IS STILL COMPLETELY SOLUBLE IN DIMETHYL FORMAMIDE AT 10% CONCENTRATION. GRADUAL FEEDING OF MONOMER CAN BE USED.
Inventors
- 👤 K Kliment
- 👤 J Rutherford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:35
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/10; C08F220/26; C08F220/28; C08F220/281
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) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |