Patent US3577357A successfully refreshed from Google Patents.
US3577357A
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Selectively sulfonated block copolymers
Assignee: Shell USA Inc
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Filing: 1968-11-29
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Granted: 1971-05-04
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Expires: 1988-11-29
Abstract
Abstract BLOCK COPOLYMERS EXHIBITING WATER ABSORPTION CHARACTERISTICS INDICATING THEIR USE IN WATER PURIFICATION MEMBRANES AND THE LIKE COMPRISE BLOCK COPOLYMERS HAVING SULFONATED POLYVINYL ARENE BLOCKS AND ALPHA-OLEFIN ELASTOMERIC BLOCKS, THE SULFUR CONTENT OF THE COPOLYMERS VARYING FROM ABOUT 1% BY WEIGHT TO ONE SULFONATED RADICAL PER MONOVINYL ARENE UNIT.
Inventors
- 👤 De Loss E Winkler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:31
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/76; B01D71/80; C; C08; C08F; C08F8/00; C08F8/34; C08F8/36
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) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |