US3817933A
Expired / Lapsed
US
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Process for the preparation of high molecular weight hydroxypoly-urethanes which are soluble in organic solvents
Assignee: Bayer AG
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Filing: 1972-09-28
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Granted: 1974-06-18
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Expires: 1992-09-28
Abstract
Abstract A THREE-STAGE PROCESS FOR THE PREPARATION OF HIGH MOLECULAR WEIGHT POLYURETHANES WHICH ARE SOLUBLE IN ORGANIC SOLVENTS AND WHICH CONTAIN FREE HYDROXYL GROUPS IS DISCLOSED WHEREIN A DIHYDROXY COMPOUND AND A DIISOCYANATE ARE REACTED AT A TEMPERATURE OF 110: C. TO 160*C. IN THE PRESENCE OF A NON-POLAR OR SLIGHTLY POLAR SOLVENT IN A FIRST STAGE AND THEN REACTED AT A REDUCED TEMPERATURE OF 60* C. TO 100* C. FOR 12 TO 72 HOURS IN A SECOND STAGE AND THEN THE SOLVENT IS REMOVED IN A THIRD STAGE AT A TEMPERATURE ABOVE 100*C.
Inventors
- 👤 G Niederdellmann
- 👤 H Bormann
- 👤 H Conrad
- 👤 G Oertel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:03
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/82; C08G18/08; C08G18/0838; C08G18/0842; C08G18/0847; C08G18/0852; C08G18/10; C08G18/28; C08G18/40; C08G18/42; Y; Y10; Y10S; Y10S528/00; Y10S528/902
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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |