US4464323A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing high strength cellulosic fibers
Assignee: EIDP Inc
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Filing: 1982-08-09
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Granted: 1984-08-07
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Expires: 2002-08-09
Abstract
Abstract High strength, high modulus cellulose triacetate fibers are produced by spinning a 30-42% 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 trifluoroacetic acid and another solvent having a molecular weight of less than 160 in a mol ratio of 0.3-3.0 through an air gap into a coagulating bath. The fibers are optionally heat treated under tension or saponified to provide high strength high modulus regenerated cellulose fibers.
Inventors
- 👤 John P. O'Brien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:26
CPC Classifications
D; D01; D01F; D01F11/00; D01F11/02; D01F2/00; D01F2/24; D01F2/28
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
101 words
Process for preparing high strength cellulose triacetate fibers having at least 42.5% by weight acetyl groups by extruding a solution of cellulose triacetate in a solvent mixture comprising an organic acid having a pKa of no more than 3.5 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 30-42% by weight, and the mol ratio of organic acid to the other solvent is 0.3 to 3.0.
Claim 2
Dependent Claim
101 words
Process for preparing high strength cellulose triacetate fibers having at least 42.5% by weight acetyl groups by extruding a solution of cellulose triacetate in a solvent mixture comprising an organic acid having a pKa of no more than 3.5 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 30-42% by weight, and the mol ratio of organic acid to the other solvent is 0.3 to 3.0.
Claim 3
Dependent Claim
11 words
Process of claim 5 wherein the organic acid is trifluoroacetic acid.
Claim 4
Dependent Claim
21 words
Process of claim 8 wherein the other solvent is selected from the group consisting of water, methylene chloride and formic acid.
Claim 5
Dependent Claim
30 words
Process of claim 9 wherein the other solvent is water, the mol ratio of trifluoroacetic acid to water is 1.5 to 2.5 and the polymer concentration is 35-42% by weight.
Claim 6
Dependent Claim
32 words
Process of claim 9 wherein the other solvent is methylene chloride, the mol ratio of trifluoroacetic acid to methylene chloride is 1.0 to 2.5 and the polymer concentration is 34-42% by weight.
Claim 7
Dependent Claim
32 words
Process of claim 9 wherein the other solvent is formic acid, the mol ratio of trifluoroacetic acid to formic acid is 0.3 to 1.0 and the polymer concentration is 34-42% by weight.
Claim 8
Dependent Claim
16 words
Process of claim 9 wherein the coagulation bath is a 1-3 carbon atom alcohol or diol.
Claim 9
Dependent Claim
10 words
Process of claim 13 wherein the coagulating bath is methanol.
Claim 10
Dependent Claim
25 words
Process for increasing the strength and modulus of fibers produced by the process of claim 7 wherein the fibers are subsequently drawn 1-10% in steam.
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) | 1987-08-07 | 1988-02-06 | 1988-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-07 | 1992-02-06 | 1992-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-07 | 1996-02-06 | 1996-08-07 | $7700.00 | Window Closed / Lapsed |