US4129451A
Expired / Lapsed
US
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Spinnable cellulose solution and process for making same
Assignee: Rhone Poulenc Textile SA
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Filing: 1977-07-14
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Granted: 1978-12-12
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Expires: 1997-07-14
Abstract
Abstract Spinnable, shapable solutions of celluose are disclosed, wherein the solutions contain native cellulose in a mixture of dimethylsulphoxide (DMSO) and formaldehyde. The cellulose has a degree of polymerization (DP) of at least 400 and a concentration in the mixture of at least 6% by weight, based on the volume of DSMO. The formaldehyde/cellulose weight ratio is 0.2 to 2, and the solutions have a water content no greater than 5,000 ppm by weight. The solutions are obtained by dissolving the cellulose in a mixture of DMSO and formaldehyde, at a formaldehyde/cellulose weight ratio of at least 1, and thereafter the formaldehyde/cellulose weight ratio is reduced, if necessary, to the final level of about 0.2 to 2. The solutions can be converted into films, membranes, sponges, varnishes, paints, and especially into filaments, with the filaments being generally similar in properties to regenerated cellulose filaments.
Inventors
- 👤 Jacques Menault
- 👤 Henry Rodier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:52
CPC Classifications
C; C08; C08B; C08B16/00; C08L; C08L1/00; C08L1/02; D; D01; D01F; D01F2/00
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
69 words
A spinnable, shapable solution of native cellulose in dimethylsulphoxide and formaldehyde, said cellulose having a degree of polymerization of at least 400 and a concentration in said solution of at least 6% by weight of cellulose per volume of dimethylsulphoxide, said formaldehyde present in a formaldehyde/cellulose weight ratio of about 0.2 to less than 0.8, said solution having a water content no greater than about 5000 ppm by weight.
Claim 2
Dependent Claim
69 words
A spinnable, shapable solution of native cellulose in dimethylsulphoxide and formaldehyde, said cellulose having a degree of polymerization of at least 400 and a concentration in said solution of at least 6% by weight of cellulose per volume of dimethylsulphoxide, said formaldehyde present in a formaldehyde/cellulose weight ratio of about 0.2 to less than 0.8, said solution having a water content no greater than about 5000 ppm by weight.
Claim 3
Dependent Claim
20 words
Solution of claim 1, wherein said solution has a Np value less than 250 and a clogging index above 70.
Claim 4
Dependent Claim
25 words
Solution of claim 2, wherein said solution has a Np value no greater than about 200 and a clogging index of at least about 80.
Claim 5
Dependent Claim
26 words
Solution of claim 2, wherein the cellulose concentration of said solution is from about 8 to about 20% by weight of cellulose per volume of dimethylsulphoxide.
Claim 6
Dependent Claim
20 words
Solution of claim 4, wherein the water content of said solution is no greater than about 2000 ppm by weight.
Claim 7
Dependent Claim
17 words
Solution of claim 2, wherein the formaldehyde/cellulose weight ratio of said solution is between 0.2 and 0.6.
Claim 8
Dependent Claim
87 words
Process for producing spinnable, shapable solutions of native cellulose, said process comprising dissolving a native cellulose having a DP of at least about 400 and a moisture content below about 1% by weight in DMSO and formaldehyde at a formaldehyde/cellulose weight ratio of at least 1, and a concentration of cellulose of at least 6% by weight per volume of DMSO, the moisture content of the solution being no greater than 5,000 ppm by weight, and thereafter reducing the formaldehyde/cellulose weight ratio, to about 0.2 to 0.8.
Claim 9
Dependent Claim
87 words
Process for producing spinnable, shapable solutions of native cellulose, said process comprising dissolving a native cellulose having a DP of at least about 400 and a moisture content below about 1% by weight in DMSO and formaldehyde at a formaldehyde/cellulose weight ratio of at least 1, and a concentration of cellulose of at least 6% by weight per volume of DMSO, the moisture content of the solution being no greater than 5,000 ppm by weight, and thereafter reducing the formaldehyde/cellulose weight ratio, to about 0.2 to 0.8.
Claim 10
Dependent Claim
18 words
Process of claim 7, wherein the DMSO has a water content of less than 1,000 ppm by weight.
Claim 11
Dependent Claim
17 words
Process of claim 8, wherein the formaldehyde/cellulose weight ratio during said dissolving is between 1 and 2.
Claim 12
Dependent Claim
28 words
Process of claim 8, wherein said cellulose has a DP of at least 1,000 and the DMSO has a water content of less than 500 ppm by weight.
Claim 13
Dependent Claim
17 words
Process of claim 8, wherein the formaldehyde is introduced into the DMSO in the form of paraformaldehyde.
Claim 14
Dependent Claim
15 words
Process of claim 8, wherein the formaldehyde/cellulose weight ratio is reduced to 0.2 to 0.6.
Claim 15
Dependent Claim
14 words
Process of claim 8, wherein 8 to 20 weight percent of cellulose is dissolved.
Claim 16
Dependent Claim
18 words
Process of claim 8, wherein the cellulose is dissolved at a temperature of about 90° to 130° C.
Claim 17
Dependent Claim
18 words
Process of claim 8, wherein the water content of said solution is less than 2,000 ppm by weight.
Claim 18
Dependent Claim
107 words
Process for producing spinnable, shapeable solutions of native cellulose, said process comprising dissolving a native cellulose having a DP of at least about 400 and a moisture content below about 1 percent by weight in DMSO and formaldehyde at a formaldehyde/cellulose weight ratio of at least one, and a concentration of cellulose of at least 6 percent by weight per volume of DMSO, the moisture content of the solution being no greater than 5000 ppm by weight, and thereafter reducing the formaldehyde/cellulose weight ratio by removal of formaldehyde from said solution until the formaldehyde/cellulose weight ratio is within the range of about 0.2 to less than 0.8.
Claim 19
Dependent Claim
107 words
Process for producing spinnable, shapeable solutions of native cellulose, said process comprising dissolving a native cellulose having a DP of at least about 400 and a moisture content below about 1 percent by weight in DMSO and formaldehyde at a formaldehyde/cellulose weight ratio of at least one, and a concentration of cellulose of at least 6 percent by weight per volume of DMSO, the moisture content of the solution being no greater than 5000 ppm by weight, and thereafter reducing the formaldehyde/cellulose weight ratio by removal of formaldehyde from said solution until the formaldehyde/cellulose weight ratio is within the range of about 0.2 to less than 0.8.
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) | 1981-12-11 | 1982-06-12 | 1982-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-11 | 1986-06-12 | 1986-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-11 | 1990-06-12 | 1990-12-12 | $7700.00 | Window Closed / Lapsed |