Patent US781488A successfully refreshed from Google Patents.
US4237274A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of solutions of cellulose derivatives which can be coagulated and spun to form regenerated cellulose _bodies
Assignee: SNIA Viscosa SpA
•
Filing: 1979-02-23
•
Granted: 1980-12-02
•
Expires: 1999-02-23
Abstract
Abstract A process for the preparation of solutions of cellulose derivatives from which formed bodies, such as fibres or films, of regenerated cellulose can be obtained by coagulation and regeneration, e.g. by wet spinning, is disclosed. The cellulose is transformed into a methylol derivative containing more than 2 units of formaldehyde per anydroglucosidic unit, which derivative is soluble in organic solvents of the class consisting of polar aprotic solvents constituted by N-substituted amides, pyridine and formamide. The methylol derivative is prepared by treating cellulose with paraformaldehyde and dimethylsulphoxide. The methylol derivative is then dissolved in one of the aforesaid solvents, preferably dimethylformamide or dimethylacetamide, to provide spinnable viscous solutions from which formed bodies can be obtained, e.g. by spinning in an aqueous alkaline bath.
Inventors
- 👤 Roberto Leoni
- 👤 Alberto Baldini
- 👤 Gianfranco Angelini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:12
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/09; C08J3/091; C08J3/096; C08B; C08B1/00; C08B1/003; D; D01; D01F; D01F2/00; D01F2/06; D01F2/08; C08J2301/00; C08J2301/08; C08J2301/26; C08J2301/28
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
73 words
A process for the preparation of solutions of cellulose derivatives from which regenerated cellulose bodies may be prepared by coagulation and regeneration, characterized in that a methylol derivative of cellulose is prepared, which derivative contains more than 2 units for formaldehyde per anhydroglucosidic unit, and said derivative is dissolved in an organic spinning solvent selected from the group consisting of polar aprotic solvents containing N-substituted amide moieties in their structure, pyridine, and formamide.
Claim 2
Dependent Claim
73 words
A process for the preparation of solutions of cellulose derivatives from which regenerated cellulose bodies may be prepared by coagulation and regeneration, characterized in that a methylol derivative of cellulose is prepared, which derivative contains more than 2 units for formaldehyde per anhydroglucosidic unit, and said derivative is dissolved in an organic spinning solvent selected from the group consisting of polar aprotic solvents containing N-substituted amide moieties in their structure, pyridine, and formamide.
Claim 3
Dependent Claim
22 words
A process according to claim 1, characterized in that the methylol derivative contains at least 3 units of formaldehyde per anhydroglucosidic unit.
Claim 4
Dependent Claim
21 words
A process according to claim 1, characterized in that the methylol derivative is prepared by contacting cellulose with paraformaldehyde and DMSO.
Claim 5
Dependent Claim
31 words
A process according to claim 1, characterized in that the spinning solvent is a polar aprotic solvent selected from the group consisting of dimethylformamide (DMF), dimethylacetamide, tetramethylurea, N-methylpyrrolidone and hexamethylphosphoramide (HMPT).
Claim 6
Dependent Claim
46 words
A process according to claim 3, characterized in that cellulose is dissolved in a system composed of paraformaldehyde and DMSO, and the methylol derivative of cellulose thus formed is separated from the DMSO and brought into solution, without regeneration of the cellulose, in the spinning solvent.
Claim 7
Dependent Claim
46 words
A process according to claim 5, characterized in that the methylol derivative is separated from the DMSO by precipitating it from the solution in DMSO by means of at least one agent which is a non-solvent non-regenerating agent of the cellulose and is miscible with DMSO.
Claim 8
Dependent Claim
29 words
A process according to claim 6, characterized in that the non-solvent non-regenerating agent is selected from the group consisting of ethers, esters, alcohols, aldehydes, ketones and chlorinated organic liquids.
Claim 9
Dependent Claim
32 words
A process according to claim 7, characterized in that the non-solvent non-regenerating agent is selected from the group consisting of cyclohexane, acetone, benzaldehyde, chloroform, tetrahydrofurane, dioxane, ethylene glycol nonoethylether, dimethylether, and methanol.
Claim 10
Dependent Claim
24 words
A process according to claim 6, characterized in that the non-solvent non-regenerating agent is selected from the group consisting of acetonitrile and ethyl acetate.
Claim 11
Dependent Claim
36 words
A process according to claim 5, characterized in that the dissolution of the cellulose is effected in the presence of an amount of formaldehyde in excess of the theoretical amount relative to the desired methylol derivative.
Claim 12
Dependent Claim
31 words
A process according to claim 5, characterized in that the solution of the cellulose derivative in DMSO is concentrated by evaporation until a major portion of the DMSO has been removed.
Claim 13
Dependent Claim
44 words
A process according to claim 5, characterized in that an organic spinning solvent having a boiling point higher than that of DMSO is added to the solution of methylol derivative in DMSO and subsequently at least a major portion of the DMSO is distilled.
Claim 14
Dependent Claim
48 words
A process according to claim 5, characterized in that a major portion of the DMSO is distilled from the solution of methylol derivative in DMSO, and said methylol derivative is precipitated by means of a non-solvent non-regenerating agent, and the precipitate is dissolved in the organic spinning solvent.
Claim 15
Dependent Claim
49 words
A process according to claim 5, characterized in that an organic spinning solvent is added to the solution of methylol derivative in DMSO, said derivative is precipitated from the resulting solution by means of a non-solvent non-regenerating agent, and the said derivative is re-dissolved in the same spinning solvent.
Claim 16
Dependent Claim
39 words
A process according to claim 5, characterized in that the methylol derivative is precipitated from its solution in the spinning solvent by means of a non-solvent non-regenerating agent, and the precipitate is washed and thereafter dissolved in spinning solvent.
Claim 17
Dependent Claim
34 words
A process according to claim 3, characterized in that the methylol derivative is prepared by contacting cellulose and paraformaldehyde with an amount of DMSO smaller than that required for the formation of a solution.
Claim 18
Dependent Claim
28 words
A process according to claim 16, characterized in that the cellulose and the formaldehyde are contacted with the DMSO and are heated to temperatures above 100 ° C.
Claim 19
Dependent Claim
35 words
A process according to claim 16, characterized in that the cellulose, the formaldehyde and the DMSO are left in contact at elevated temperatures until a translucid, tacky mass, soluble in the spinning solvent is formed.
Claim 20
Dependent Claim
32 words
A process according to claim 16, characterized in that from 4 to 7.5 parts by weight of DMSO and from 1.3 to 2 parts of paraformaldehyde per part of cellulose are used.
Claim 21
Dependent Claim
25 words
A process according to claim 16, characterized in that the methylol derivative is dissolved in the spinning solvent at elevated temperatures, but below 100° C.
Claim 22
Dependent Claim
56 words
A process for the preparation of formed bodies, in particular filaments, of regenerated cellulose, characterized in that a solution of cellulose derivative in a spinning solvent is prepared according to claim 1, and the cellulose derivative is coagulated from said solution and the cellulose is regenerated by means of at least one coagulating and regenerating bath.
Claim 23
Dependent Claim
16 words
A process according to claim 21, characterized in that the bath is an aqueous alkaline bath.
Claim 24
Dependent Claim
18 words
A process according to claim 22, characterized in that the aqueous alkaline bath is an aqueous ammonia solution.
References Cited (Backward Citations)
US3776692A
Cited
US4022631A
Cited
US4056675A
Cited
US4086418A
Cited
US4097666A
Cited
US4145391A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-02 | 1984-06-02 | 1984-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-02 | 1988-06-02 | 1988-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-02 | 1992-06-02 | 1992-12-02 | $7700.00 | Window Closed / Lapsed |