US4097666A
Expired / Lapsed
US
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Solvent system for polysaccharides
Assignee: Lawrence University
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Filing: 1976-04-29
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Granted: 1978-06-27
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Expires: 1996-04-29
Abstract
Abstract Natural or modified polysaccharides are dissolved in a solvent system comprising dimethyl sulfoxide and formaldehyde. The solvent system is particularly suitable for dissolving cellulose due to the fact that cellulose is rapidly dissolved under moderate conditions of temperature and pressure. The dissolved polysaccharides are readily recovered from the solvent system by diluting the solvent system with water or a short chain alcohol.
Inventors
- 👤 Donald C. Johnson
- 👤 Myron D. Nicholson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:20
CPC Classifications
C; C08; C08L; C08L1/00; C08L1/02; C08B; C08B1/00; C08B1/003; C08B11/00; C08B11/02; C08B11/04; C08B11/08; C08B16/00; C08L1/08; C08L1/26; C08L1/28; C08L1/284
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
18 words
A composition comprising a natural or modified polysaccharide dissolved in a solvent system comprising dimethyl sulfoxide and formaldehyde.
Claim 2
Dependent Claim
18 words
A composition comprising a natural or modified polysaccharide dissolved in a solvent system comprising dimethyl sulfoxide and formaldehyde.
Claim 3
Dependent Claim
12 words
A composition in accordance with claim 1 wherein said polysaccharide is cellulose.
Claim 4
Dependent Claim
31 words
A composition in accordance with claim 1 wherein said formaldehyde is present in said solvent system at a ratio of from about 0.1:1 to about 20:1 by weight of said polysaccharide.
Claim 5
Dependent Claim
14 words
A composition in accordance with claim 1 wherein said formaldehyde is derived from paraformaldehyde.
Claim 6
Dependent Claim
21 words
A composition in accordance with claim 1 wherein water present in said solvent system is limited to less than about 1%.
Claim 7
Independent Claim
18 words
A method for dissolving polysaccharides comprising adding said polysaccharide to a solvent system comprising dimethyl sulfoxide and formaldehyde.
Claim 8
Independent Claim
18 words
A method for dissolving polysaccharides comprising adding said polysaccharide to a solvent system comprising dimethyl sulfoxide and formaldehyde.
Claim 9
Dependent Claim
12 words
A method in accordance with claim 6 wherein said polysaccharide is cellulose.
Claim 10
Dependent Claim
31 words
A method in accordance with claim 6 wherein said formaldehyde is present in said solvent system at a ratio of from about 0.1:1 to about 20:1 by weight of said polysaccharide.
Claim 11
Dependent Claim
24 words
A method in accordance with claim 6 wherein said formaldehyde is derived from paraformaldehyde by heating said solvent system containing dimethyl sulfoxide and paraformaldehyde.
Claim 12
Dependent Claim
23 words
A method in accordance with claim 6 wherein water present in said solvent system is limited to less than about 1% by weight.
Claim 13
Independent Claim
19 words
A method for manufacture of methylol cellulose comprising adding cellulose to a solvent system comprising dimethyl sulfoxide and formaldehyde.
Claim 14
Independent Claim
19 words
A method for manufacture of methylol cellulose comprising adding cellulose to a solvent system comprising dimethyl sulfoxide and formaldehyde.
Claim 15
Dependent Claim
31 words
A method in accordance with claim 11 wherein said formaldehyde is present in said solvent system at a ratio of from about 0.1:1 to about 20:1 by weight of said polysaccharide.
Claim 16
Dependent Claim
24 words
A method in accordance with claim 11 wherein said formaldehyde is derived from paraformaldehyde by heating said solvent system comprising dimethyl sulfoxide and paraformaldehyde.
Claim 17
Dependent Claim
24 words
A method in accordance with claim 11 wherein said water present in said solvent system is limited to less than about 1% by weight.
Claim 18
Independent Claim
52 words
A method for manufacture of a cellulose fiber comprising dissolving cellulose in a solvent system comprising dimethyl sulfoxide and formaldehyde, and regenerating a fiber from said celluose solution by injecting a stream of said solution into a regeneration medium selected from the group consisting of an aqueous medium and short chain alcohols.
Claim 19
Independent Claim
52 words
A method for manufacture of a cellulose fiber comprising dissolving cellulose in a solvent system comprising dimethyl sulfoxide and formaldehyde, and regenerating a fiber from said celluose solution by injecting a stream of said solution into a regeneration medium selected from the group consisting of an aqueous medium and short chain alcohols.
Claim 20
Dependent Claim
22 words
A method in accordance with claim 15 wherein said short chain alcohols are C-1 - C-6 straight or branched chain aliphatic alcohols.
Claim 21
Dependent Claim
18 words
A method in accordance with claim 15 wherein said short chain alcohols are selected from methanol and ethanol.
Claim 22
Independent Claim
53 words
A method for the manufacture of a cellulose film comprising dissolving cellulose in a solvent system comprising dimethyl sulfoxide and formaldehyde and regenerating a film from said cellulose solution by injecting a film of said solution into a regeneration medium selected from the group consisting of an aqueous medium and short chain alcohols.
Claim 23
Independent Claim
53 words
A method for the manufacture of a cellulose film comprising dissolving cellulose in a solvent system comprising dimethyl sulfoxide and formaldehyde and regenerating a film from said cellulose solution by injecting a film of said solution into a regeneration medium selected from the group consisting of an aqueous medium and short chain alcohols.
Claim 24
Dependent Claim
29 words
A method for the manufacture of a cellulose film in accordance with claim 18 wherein said short chain alcohols are C-1 - C-6 straight or branched chain aliphatic alcohols.
Claim 25
Dependent Claim
25 words
A method for the manufacture of a cellulose film in accordance with claim 18 wherein said short chain alcohols are selected from methanol and ethanol.
Claim 26
Independent Claim
62 words
A method for making paper comprising treating a cellulose source with a solvent system comprising dimethyl sulfoxide and formaldehyde so as to dissolve cellulose from said source, regenerating said cellulose from said solution by diluting said solution with a regeneration medium selected from the group consisting of an aqueous medium and short chain alcohols, and forming a web from said regenerated cellulose.
Claim 27
Independent Claim
62 words
A method for making paper comprising treating a cellulose source with a solvent system comprising dimethyl sulfoxide and formaldehyde so as to dissolve cellulose from said source, regenerating said cellulose from said solution by diluting said solution with a regeneration medium selected from the group consisting of an aqueous medium and short chain alcohols, and forming a web from said regenerated cellulose.
Claim 28
Dependent Claim
25 words
A method for making paper in accordance with claim 21 wherein said short chain alcohols are C-1 - C-6 straight or branched chain aliphatic alcohols.
Claim 29
Dependent Claim
21 words
A method for making paper in accordance with claim 21 wherein said short chain alcohols are selected from methanol and ethanol.
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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) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |