US5202184A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for producing para-aramid pulp and pulp produced thereby
Assignee: EIDP Inc
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Filing: 1991-07-01
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Granted: 1993-04-13
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Expires: 2011-07-01
Abstract
Abstract A method for producing para-aramid pulp includes forming a liquid, actively-polymerizing solution and subjecting the solution to orienting flow which produces an optically anisotropic liquid solution with polymer chains oriented in the direction of the flow. When the solution has a viscosity sufficient to maintain the orientation of the polymer chains, the solution is incubated until it gels. The gel is cut transversely at intervals and para-aramid pulp is isolated from the gel. Para-aramid pulp produced by the process can be used similarly to pulp produced from spun fiber.
Inventors
- 👤 Roland T. Brierre
- 👤 Stephan C. De La Veaux
- 👤 James E. Geary, Jr.
- 👤 Wesley Memeger, Jr.
- 👤 Michael L. Trancynger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:35
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/58; D01F6/60; D01F6/605; D01D; D01D5/00; D01D5/38; D21; D21H; D21H13/00; D21H13/10; D21H13/20; D21H13/26; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2904; Y10T428/2913; Y10T428/2922; Y10T428/2925; Y10T428/2933; Y10T428/2964; Y10T428/2967; Y10T428/2969
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
77 words
Para-aramid pulp consisting essentially of pulp-like short fibers comprised of bundles of sub-micron diameter fibrils of para-aramid free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g.
Claim 2
Dependent Claim
77 words
Para-aramid pulp consisting essentially of pulp-like short fibers comprised of bundles of sub-micron diameter fibrils of para-aramid free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g.
Claim 3
Dependent Claim
18 words
The para-aramid pulp of claim 1 wherein the inherent viscosity of said para-aramid is between 3.0 and 4.25.
Claim 4
Dependent Claim
14 words
The para-aramid pulp of claim 1 wherein said length is less than 13 mm.
Claim 5
Dependent Claim
79 words
Poly(p-phenylene terephthalamide) pulp consisting essentially of pulp-like short fibers comprised of bundles of sub-micron diameter fibrils of poly(p-phenylene terephthalamide) free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g.
Claim 6
Dependent Claim
79 words
Poly(p-phenylene terephthalamide) pulp consisting essentially of pulp-like short fibers comprised of bundles of sub-micron diameter fibrils of poly(p-phenylene terephthalamide) free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g.
Claim 7
Dependent Claim
14 words
The para-aramid pulp of claim 4 wherein said length is less than 13 mm.
Claim 8
Dependent Claim
94 words
Para-aramid pulp consisting essentially of pulp-like short fibers comprised of bundles of sub-micron diameter fibrils of para-aramid free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g, said fibrils having a wavy, structure and said fibers being fibrillated along the length of the fiber.
Claim 9
Dependent Claim
94 words
Para-aramid pulp consisting essentially of pulp-like short fibers comprised of bundles of sub-micron diameter fibrils of para-aramid free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g, said fibrils having a wavy, structure and said fibers being fibrillated along the length of the fiber.
Claim 10
Dependent Claim
98 words
Para-aramid pulp consisting essentially of pulp-like uncollapsed, never-dried short fibers comprised of bundles of sub-micron diameter fibrils of para-aramid free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, and, when dried, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g, said short fibers containing at least 30% water based on the weight of the dry fiber.
Claim 11
Dependent Claim
98 words
Para-aramid pulp consisting essentially of pulp-like uncollapsed, never-dried short fibers comprised of bundles of sub-micron diameter fibrils of para-aramid free of sulfonic acid groups and having an inherent viscosity of between 2.0 and 4.5, having a diameter of between 1μ to 150μ and a length of between 0.2 mm and 35 mm, and, when dried, having a crystallinity index of less than 50, a crystallite size of less than 40 Å, and a surface area of greater than 2 m 2 /g, said short fibers containing at least 30% water based on the weight of the dry fiber.
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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) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |