Patent US4456749A successfully refreshed from Google Patents.
US4456749A
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Procedure for precipitating cellulose derivative
Assignee: Neste Oyj
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Filing: 1982-12-30
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Granted: 1984-06-26
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Expires: 2002-12-30
Abstract
Abstract The present invention concerns a procedure for precipitating cellulose carbamate from an aqueous alkali solution. The solution is brought into contact with an aqueous solution of sulphuric acid containing one or several cations selected from the group consisting of Na, Al, Mg, Zn and Ca cations, whereby in the precipitation of cellulose carbamate the advantage is gained that the dry matter content of the fibre can be made high enough.
Inventors
- 👤 Leo Mandell
- 👤 Vidar Eklund
- 👤 Kurt Ekman
- 👤 Jouko Huttunen
- 👤 Olli Turunen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:03
CPC Classifications
C; C07; C07D; C07D231/00; C07D231/02; C07D231/10; C07D231/12; C07D249/00; C07D249/02; C07D249/08; C08; C08B; C08B15/00; C08B15/05; C08B15/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
44 words
Procedure for precipitating cellulose carbamate from an aqueous alkali solution, characterized in that the solution is brought into contact with an aqueous solution of sulphuric acid containing one or several cations selected from the group consisting of Na, Al, Mg, Zn and Ca cations.
Claim 2
Dependent Claim
44 words
Procedure for precipitating cellulose carbamate from an aqueous alkali solution, characterized in that the solution is brought into contact with an aqueous solution of sulphuric acid containing one or several cations selected from the group consisting of Na, Al, Mg, Zn and Ca cations.
Claim 3
Dependent Claim
34 words
Procedure according to claim 1, characterized in that the sulphuric acid solution contains 2-20 % by weight sulphuric acid, 3-30% by weight sodium sulphate and 0.1-25% by weight aluminium, magnesium, calcium or zinc sulphate.
Claim 4
Dependent Claim
36 words
Procedure according to claim 1, characterized in that the alkali solution of the carbamate is pressed through a perforated or slit-like orifice into the sulphuric acid solution to the purpose of precipitating carbamate fibre or film.
Claim 5
Dependent Claim
23 words
Procedure according to any one of claims 1, characterized in that the alkali solution of carbamate contains 4-15% by weight of cellulose carbamate.
References Cited (Backward Citations)
GB216475A
Cited
US2129708A
Cited
US2134825A
Cited
GB516672A
Cited
GB1265010A
Cited
EP0057105A2
Cited
US4404369A
Cited
US4367191A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-26 | 1987-12-26 | 1988-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-26 | 1991-12-26 | 1992-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-26 | 1995-12-26 | 1996-06-26 | $7700.00 | Window Closed / Lapsed |