US3728290A
Expired / Lapsed
US
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Method for the preparation of a separation medium for gel filtration
Assignee: Cytiva Sweden AB
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Filing: 1971-04-26
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Granted: 1973-04-17
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Expires: 1991-04-26
Abstract
Abstract THE PRESENT INVENTION RELATES TO AN IMPROVED METHOD FOR PREPARING A SEPARATING MEDIUM FOR GEL FILTRATION IN WHICH GAINS OF A RIGID HYDROPHILIC MACROPOROUS COPOLYMER OF ACRYLAMIDE (OR 1-VINYL-12-PYRROLIDINONE) WITH N,(''METHYLENE-BIS-ACRYLAMIDE HAS COPOLYMERIZED IN ITS PORSE A SECOND COPOLYMER OF ONE OR MORE ACRYLAMIDES (OR 1VINYL -2- PYRROLIDINONE) WITHIN N,(''-METHYLENE-BIS-ACRYLAMIDE IN THE PRESENCE OF AN INITIATOR (AS SET FORTH IN U.S.P. 3,616,936) CHARACTERIZED IN THAT THE INITIATOR IS PRESENT IN THE PORES OF THE RIGID HYDROPHILIC, MACROPOROUS COPOLYMER WHEN THE COPOLYMERIZABLE SUBSTENCES OF SAID SECOND COPOLYMER ARE INTRODUCED THEREINTO.
Inventors
- 👤 I Johansson
- 👤 M Joustra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:18
CPC Classifications
C; C08; C08F; C08F265/00; C08F265/10; B; B01; B01J; B01J20/00; B01J20/22; Y; Y10; Y10S; Y10S521/00; Y10S521/905
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) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |