US4530999A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing cellulose carbamate fibers or films
Assignee: Neste Oyj
•
Filing: 1984-11-01
•
Granted: 1985-07-23
•
Expires: 2004-11-01
Abstract
Abstract The production of cellulose carbamate fibers or films by reacting cellulose with urea to form cellulose carbamate which is dissolved in alkaline solution to form a spinning solution which is spun through an acid precipitation bath is improved by subjecting the cellulose carbamate prior to dissolution in alkaline solution to irradiation of about 0.05-10 Mrad. After dissolution in alkaline solution the same may be subjected to further mild irradiation.
Inventors
- 👤 Johan-Fredrik Selin
- 👤 Jouko Huttunen
- 👤 Olli Turunen
- 👤 Jan Fors
- 👤 Vidar Eklund
- 👤 Kurt Ekman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:30
CPC Classifications
D; D01; D01F; D01F2/00; C; C08; C08B; C08B15/00; C08B15/05; C08B15/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
101 words
In a method for producing cellulose carbamate fiber or film, comprising the steps of reacting cellulose and urea at elevated temperature to form cellulose carbamate, dissolving the thus-formed cellulose carbamate in an alkaline solution to prepare a spinning solution from which cellulose carbamate can be spun, and spinning the thus-prepared solution through an acid precipitation solution to form fiber or film, the improvement comprising the step of irradiating the thus-formed cellulose carbamate with from about 0.05 to about 10 Mrad of radiation dose prior to dissolving the same in the alkaline solution, whereby the dissolvability of the cellulose carbamate is increased.
Claim 2
Dependent Claim
101 words
In a method for producing cellulose carbamate fiber or film, comprising the steps of reacting cellulose and urea at elevated temperature to form cellulose carbamate, dissolving the thus-formed cellulose carbamate in an alkaline solution to prepare a spinning solution from which cellulose carbamate can be spun, and spinning the thus-prepared solution through an acid precipitation solution to form fiber or film, the improvement comprising the step of irradiating the thus-formed cellulose carbamate with from about 0.05 to about 10 Mrad of radiation dose prior to dissolving the same in the alkaline solution, whereby the dissolvability of the cellulose carbamate is increased.
Claim 3
Dependent Claim
40 words
In the method of claim 1, the improvement comprising the additional step of irradiating the cellulose carbamate after dissolution in the alkaline solution, whereby the total irradiation dose of the cellulose carbamate being from about 0.05 to about 10 Mrad.
Claim 4
Dependent Claim
20 words
The method of claim 1, wherein the cellulose carbamate is irradiated in the form of loose fibers or a web.
Claim 5
Dependent Claim
20 words
The method of claim 2 wherein the cellulose carbamate is irradiated in the form of loose fibers or a web.
Claim 6
Independent Claim
84 words
A method for producing cellulose carbamate fiber or film, comprising the steps of reacting cellulose with urea to form cellulose carbamate, irradiating the thus-formed cellulose carbamate with from about 0.05 to about 10 Mrad of radiation dose, whereby the dissolvability of the cellulose carbamate is increased, dissolving the thus-irradiated cellulose carbamate in an alkaline solution to form a spinning solution, from which cellulose carbamate can be spun, and spinning the thus formed spinning solution through an acid precipitation solution to form fiber or film.
Claim 7
Independent Claim
84 words
A method for producing cellulose carbamate fiber or film, comprising the steps of reacting cellulose with urea to form cellulose carbamate, irradiating the thus-formed cellulose carbamate with from about 0.05 to about 10 Mrad of radiation dose, whereby the dissolvability of the cellulose carbamate is increased, dissolving the thus-irradiated cellulose carbamate in an alkaline solution to form a spinning solution, from which cellulose carbamate can be spun, and spinning the thus formed spinning solution through an acid precipitation solution to form fiber or film.
Claim 8
Dependent Claim
35 words
The method of claim 5, comprising the additional step of irradiating the cellulose carbamate after dissolution in the alkaline solution, the total irradiation of the cellulose carbamate being from about 0.05 to about 10 Mrad.
Claim 9
Dependent Claim
20 words
The method of claim 5 wherein the cellulose carbamate is irradiated in the form of loose fibers or a web.
Claim 10
Dependent Claim
21 words
The method of claim 6, wherein the cellulose carbamate is in the form of loose fiber or a web when irradiated.
Claim 11
Dependent Claim
20 words
The method of claim 5, wherein the cellulose remains untreated with alkali prior to, and during reaction with the urea.
Claim 12
Dependent Claim
17 words
The method of claim 5, wherein the cellulose is not irradiated prior to reaction with the urea.
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) | 1988-07-22 | 1989-01-21 | 1989-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-22 | 1993-01-21 | 1993-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-22 | 1997-01-21 | 1997-07-23 | $7700.00 | Window Closed / Lapsed |