Patent US3275593A successfully refreshed from Google Patents.
US3275593A
Expired / Lapsed
US
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Production of thermally stable polyoxymethylenes by boiling in water
Assignee: Evonik Operations GmbH
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Filing: 1963-05-10
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Granted: 1966-09-27
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Expires: 1983-05-10
Abstract
No abstract record available.
Inventors
- 👤 Querfurth Wilhelm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:27
CPC Classifications
C; C08; C08G; C08G2/00; C08G2/06; C08G2/08
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
45 words
A PROCESS FOR IMPROVING THE HEAT STABILITY OF POLYOXYMETHLENES PRODUCED BY HOMOPOLYMERIZATION OF WATER-FREE FORMALDEHYDE IN AN INERT SOLVENT IN THE PRESENCE OF A REDOX SYSTEM CATALYST WHICH COMPRISES HEATING SUCH POLYOXYMETHYLENE IN BOILING WATER UNTIL SUBSTANTIALLY NO FORMALDEHYDE CAN BE DETECTED IN SUCH WATER.
Claim 2
Dependent Claim
45 words
A PROCESS FOR IMPROVING THE HEAT STABILITY OF POLYOXYMETHLENES PRODUCED BY HOMOPOLYMERIZATION OF WATER-FREE FORMALDEHYDE IN AN INERT SOLVENT IN THE PRESENCE OF A REDOX SYSTEM CATALYST WHICH COMPRISES HEATING SUCH POLYOXYMETHYLENE IN BOILING WATER UNTIL SUBSTANTIALLY NO FORMALDEHYDE CAN BE DETECTED IN SUCH WATER.
Claim 3
Dependent Claim
29 words
THE PROCESS OF CLAIM 1 IN WHICH SAID BOILING WATER CONTAINS 0.5 TO 2.5% BY WEIGHT OF A TERITARY AMINE WITH REFERENCE TO THE POLYOXYMETHLENE BOILED IN SUCH WATER.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-09-26 | 1970-03-28 | 1970-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-09-26 | 1974-03-28 | 1974-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-09-26 | 1978-03-28 | 1978-09-27 | $7700.00 | Window Closed / Lapsed |