US4871370A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stable crystalline cellulose III polymorphs
Assignee: United States Department of Agriculture
•
Filing: 1987-06-18
•
Granted: 1989-10-03
•
Expires: 2007-06-18
Abstract
Abstract Novel cellulosic fiber with improved resistance to abrasion and increased permeability to chemicals characterized by highly stable crystalline cellulose III and cellulose IV forms is disclosed. Cellulose is selected from either fiber, yarn, fabric, cotton, or mercerized cotton treated with ammonia vapors at from about ambient to 140° C. and from about 100 psi to 1700 psi for sufficient time to alter the interatomic planar distances and produce stable crystalline cellulose III polymorph. Crystalline cellulose III can also be immersed in ethylenediamine and then boiled in dimethylformamide to completely convert the III to cellulose IV.
Inventors
- 👤 Lawrence Y. Yatsu
- 👤 Timothy A. Calamari, Jr.
- 👤 Ruth R. Benerito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:07
CPC Classifications
D; D06; D06M; D06M11/00; D06M11/58; D06M11/59; D06M11/60; D06M13/00; D06M13/322; D06M13/325; D06M13/332
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
64 words
A process for producing cellulosic fiber with improved resistance to abrasion and increased permeability to chemicals comprising: treating cellulosic fiber with ammonia vapors for sufficient time at a temperature from about ambient to about 140° C. and at a pressure from about 100 psi to about 1700 psi to sufficiently alter the interatomic planar distances to produce a highly stable crystalline cellulose III polymorph.
Claim 2
Dependent Claim
64 words
A process for producing cellulosic fiber with improved resistance to abrasion and increased permeability to chemicals comprising: treating cellulosic fiber with ammonia vapors for sufficient time at a temperature from about ambient to about 140° C. and at a pressure from about 100 psi to about 1700 psi to sufficiently alter the interatomic planar distances to produce a highly stable crystalline cellulose III polymorph.
Claim 3
Dependent Claim
26 words
The process of claim 1 wherein the cellulosic fiber is selected from the group consisting of fiber, fabric, yarn, cotton bolls, native cotton and mercerized cotton.
Claim 4
Dependent Claim
33 words
The process of claim 1 including immersing the highly stable crystalline cellulose III polymorph in ethylenediamine and then in dimethylformamide at its boiling point to completely convert said cellulose III to cellulose IV.
Claim 5
Dependent Claim
26 words
The process of claim 3 wherein the cellulosic fiber is selected from the group consisting of fiber, fabric, yarn, cotton bolls, native cotton and mercerized cotton.
Claim 6
Dependent Claim
31 words
The process of claim 1 and including: immersing the cellulosic fiber in liquid ammonia in a bomb; and, evaporating the liquid ammonia in the bomb to said pressure and said temperature.
Claim 7
Dependent Claim
15 words
The process of claim 5 and including: releasing said pressure; and, drying the cellulosic fiber.
References Cited (Backward Citations)
GB1136417A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-02 | 1993-04-03 | 1993-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-02 | 1997-04-03 | 1997-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-02 | 2001-04-03 | 2001-10-03 | $7700.00 | Window Closed / Lapsed |