US4398024A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the purification of cellulose and starch ethers
Assignee: Bayer AG
•
Filing: 1981-11-13
•
Granted: 1983-08-09
•
Expires: 2001-11-13
Abstract
Abstract A process for purification and working-up of cellulose or starch ethers using a solid-jacket sieve centrifuge for removing the suspension agent extraction with purifying agent and isolation of the purified ether product.
Inventors
- 👤 Claus-Rudiger Bernert
- 👤 Christian Kords
- 👤 Detmar Redeker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:54
CPC Classifications
C; C08; C08B; C08B31/00; C08B31/08; B; B04; B04B; B04B1/00; B04B1/20; B04B3/00; B04B3/04; C08B11/00; C08B11/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
87 words
The process for the purification and isolation of a crude reaction product comprising a cellulose or starch ether suspension by removing the suspending agent, said process comprising introducing the cellulose or starch ether suspension into a solid jacket sieve worm centrifuge, separating off the suspending agent leaving a moist solid which is then conveyed to the filter zone of said centrifuge, uniformly contacting the moist solid with a purifying agent, separating the purifying agent from the solid by centrifuge and recovering purified cellulose or starch ether solid.
Claim 2
Dependent Claim
87 words
The process for the purification and isolation of a crude reaction product comprising a cellulose or starch ether suspension by removing the suspending agent, said process comprising introducing the cellulose or starch ether suspension into a solid jacket sieve worm centrifuge, separating off the suspending agent leaving a moist solid which is then conveyed to the filter zone of said centrifuge, uniformly contacting the moist solid with a purifying agent, separating the purifying agent from the solid by centrifuge and recovering purified cellulose or starch ether solid.
Claim 3
Dependent Claim
11 words
The process according to claim 1 wherein the process is continuous.
Claim 4
Dependent Claim
17 words
The process according to claim 1 wherein the suspending agent is chemically different from the purifying agent.
Claim 5
Dependent Claim
14 words
The process according to claim 1 wherein the purifying agent is a water/alcohol mixture.
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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) | 1986-08-08 | 1987-02-07 | 1987-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-08 | 1991-02-07 | 1991-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-08 | 1995-02-07 | 1995-08-09 | $7700.00 | Window Closed / Lapsed |