Patent US4337095A successfully refreshed from Google Patents.
US4337095A
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Process for the preparation of solutions of cellulose derivatives in organic solvents having higher concentration and solutions obtained by said process
Assignee: SNIA VISCOSA SpA - NAZIONALE INDUSTRIA APPLICAZIONI VISCOSA Soc
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Filing: 1980-05-30
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Granted: 1982-06-29
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Expires: 2000-05-30
Abstract
Abstract A process for the preparation of high concentration solutions of celluloseerivatives in organic solvents comprises contacting with paraformaldehyde and the solvent a cellulose which has a polymerization degree lower than 300 and preferably not significantly higher than 200. The solvent is selected from among dimethylformamide, dimethylacetamide and N-methylpyrrolidone.
Inventors
- 👤 Roberto Leoni
- 👤 Alberto Baldini
- 👤 Angelo Calloni
- 👤 Gianfranco Angelini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:42
CPC Classifications
C; C08; C08B; C08B1/00; C08B1/003
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
43 words
A process for the preparation of a solution of a methylol derivative of cellulose in an organic solvent, comprising contacting cellulose having a polymerization degree lower than 300 with paraformaldehyde and with the solvent at a temperature sufficiently high to dissolve the cellulose.
Claim 2
Dependent Claim
43 words
A process for the preparation of a solution of a methylol derivative of cellulose in an organic solvent, comprising contacting cellulose having a polymerization degree lower than 300 with paraformaldehyde and with the solvent at a temperature sufficiently high to dissolve the cellulose.
Claim 3
Dependent Claim
13 words
Process according to claim 1, wherein the solvent is dimethylformamide, dimethylacetamide or N-methylpyrrolidone.
Claim 4
Dependent Claim
23 words
Process according to claim 2, wherein the solvent is dimethylacetamide substantially free from acetic acid and containing not more than 0.1% of water.
Claim 5
Dependent Claim
14 words
Process according to claim 1, wherein the dissolution temperature is higher than 135° C.
Claim 6
Dependent Claim
17 words
Process according to claim 1, wherein the initial CH 2 O/cellulose ratio is not lower than 8.
Claim 7
Dependent Claim
18 words
Process according to claim 1, wherein the polymerization degree of the cellulose is not substantially higher than 200.
Claim 8
Dependent Claim
29 words
Process according to claim 1, further comprising treating the solution to reduce its formaldehyde content to a value corresponding to a CH 2 O/cellulose ratio not less than 3.
Claim 9
Dependent Claim
29 words
Process according to claim 7, wherein the formaldehyde content of the solution is reduced to a value corresponding to a CH 2 O/cellulose ratio of from 5 to 10.
Claim 10
Dependent Claim
28 words
A solution of a methylol derivative of cellulose in an organic solvent having a cellulose content of from 16 to 20%, by the process according to claim 1.
References Cited (Backward Citations)
US4237274A
Cited
US4268666A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-28 | 1985-12-28 | 1986-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-28 | 1989-12-28 | 1990-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-28 | 1993-12-28 | 1994-06-29 | $7700.00 | Window Closed / Lapsed |