US4725394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing high stength cellulosic fibers
Assignee: EIDP Inc
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Filing: 1985-02-19
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Granted: 1988-02-16
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Expires: 2005-02-19
Abstract
Abstract High strength, high modulus cellulose triacetate fibers are produced by spinning a 30-50% by weight solution of cellulose triacetate having an acetyl content of at least 42.5% and an inherent viscosity of at least 5 from a solvent mixture comprising nitric acid and another solvent having a molecular weight of less than 160 in a mol ratio of 1-3 through an air gap into a coagulating bath.
Inventors
- 👤 John P. O'Brien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:46
CPC Classifications
D; D01; D01F; D01F2/00; D01F2/24; D01F2/28
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
104 words
Process for preparing high strength cellulose triacetate fibers having at least 42.5% by weight acetyl groups by extruding a high solids, optically anisotropic solution of cellulose triacetate in a solvent mixture comprising nitric acid and another solvent having a molecular weight of less than 160 through an inert noncoagulating fluid layer into a coagulating bath wherein the cellulose triacetate has an inherent viscosity of at least 5 (0.5 g/dl in hexafluoroisopropanol at 30° C.), the polymer concentration is from about 30% to about 50% by weight, and the mol ratio of nitric acid to the other solvent is from about 1 to about 3.
Claim 2
Dependent Claim
104 words
Process for preparing high strength cellulose triacetate fibers having at least 42.5% by weight acetyl groups by extruding a high solids, optically anisotropic solution of cellulose triacetate in a solvent mixture comprising nitric acid and another solvent having a molecular weight of less than 160 through an inert noncoagulating fluid layer into a coagulating bath wherein the cellulose triacetate has an inherent viscosity of at least 5 (0.5 g/dl in hexafluoroisopropanol at 30° C.), the polymer concentration is from about 30% to about 50% by weight, and the mol ratio of nitric acid to the other solvent is from about 1 to about 3.
Claim 3
Dependent Claim
19 words
Process of claim 1 wherein the other solvent is selected from the group consisting of water and methylene chloride.
Claim 4
Dependent Claim
30 words
Process of claim 2 wherein the other solvent is water, the mol ratio of nitric acid to water is 1.1 to 2.6 and the polymer concentration is 35-40% by weight.
Claim 5
Dependent Claim
20 words
Process of claim 2 wherein the coagulation bath is comprised of a 1-3 carbon atom alcohol or diol and water.
Claim 6
Dependent Claim
14 words
Process of claim 4 wherein the coagulating bath is comprised of methanol and water.
Claim 7
Dependent Claim
18 words
Process of claim 5 wherein the coagulating bath is comprised of from about 25 to about 50% methanol.
References Cited (Backward Citations)
US30352A
Cited
US1521876A
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US1943461A
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USRE30352E
Cited
FR2340344A1
Cited
US4370168A
Cited
US4464323A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-15 | 1991-08-17 | 1992-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-15 | 1995-08-17 | 1996-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-15 | 1999-08-17 | 2000-02-16 | $7700.00 | Window Closed / Lapsed |