US3795660A
Expired / Lapsed
US
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Method of isolating aromatic polysulphones
Assignee: Imperial Chemical Industries Ltd
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Filing: 1971-12-20
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Granted: 1974-03-05
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Expires: 1991-12-20
Abstract
Abstract A METHOD IS PROVIDED FOR IMPROVING THE ISOLATION OF AROMATIC POLYSULPHONES ROM THE REACTION MIXTURE IN WHICH THEY ARE FORMED COMPRISING ADDING TO THE REACTION MIXTURE AN INERT SOLVENT FOR THE AROMATIC POLUSULPHONE, THE INERT SOLVENT BEING LIQUID AT THE POLYMERIZATION TEMPERATURE BUT SOLID AT THE TEMPERATURE AT WHICH THE REACTION MIXTURE IS SUBSEQUENTLY PROCESSED.
Inventors
- 👤 R Feasey
- 👤 A Newton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:36
CPC Classifications
C; C08; C08G; C08G65/00; C08G65/34; C08G65/46; C08G75/00; C08G75/20
Claims Analysis
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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) | 1977-03-04 | 1977-09-03 | 1978-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-04 | 1981-09-03 | 1982-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-04 | 1985-09-03 | 1986-03-05 | $7700.00 | Window Closed / Lapsed |