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US4511623A Expired / Lapsed US ⏱️ 0.0 years remaining

Highly oriented aromatic polyamide short fiber

Assignee: Kolon Industries Inc
•
Filing: 1983-08-16
•
Granted: 1985-04-16
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Expires: 2003-08-16
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Abstract

Abstract High oriented poly(p-phenylenetetraphthalamide) short fibers having an inherent viscosity of at least 5.0 and a dimension of 2-12 μm in diameter and 1000-5000 μm in length are provided. These fibers have a physical form of irregular cross-sections and needle point-like ends similar to those of natural wood pulp fibers, and crystalline properties such as a crystallinity of more then 50%, an orientation angle of less than 25° and an apparent crystallite size of more that 50 Å as determined from an X-ray diffractogram scan, and a cross-section with four extinction positions through 360° rotation when observed under a polarizing microscope. These fibers are prepared, without spinning steps, by subjecting the molecular chains of poly(p-phenyleneterephthalamide) to mechanical parallelization during the growth of the chains in a polymerization system therefor containing a pyridine/amide-based solvent.

Inventors

  • 👤 Han S. Yoon
  • 👤 Tae W. Son

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 06:19
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/02; C08G69/08; C08G69/14; C08G69/16; D; D01; D01D; D01D5/00; D01D5/26; C08G69/26; C08G69/32; D01D5/38; D01F; D01F6/00; D01F6/58; D01F6/60; D01F6/605; D21; D21H; D21H13/00; D21H13/10; D21H13/20; D21H13/26; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2904; Y10T428/2913; Y10T428/2973; Y10T428/2976

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 129 words
A fiber of poly(p-phenyleneterephthalamide) characterized by having: a pulp-like short fiber form of about 2-100 μm in diameter and about 1,000-50,000 μm in length; irregular cross-sections in a plane taken perpendicular to the fiber length and needle point-like ends similar to those of natural wood pulp fibers; an inherent viscosity of at least 5.0 as measured at a concentration of 0.5 g of polymer in 100 ml of 97% concentrated sulfuric acid at 30° C.; a crystallinity of more than 50%, an orientation angle of less than 25°, and an apparent crystallite size of more than 50 Angstroms, based upon X-ray diffraction pattern data; and a cross-section with four extinction positions through 360° rotation of a cross-sectional specimen of said fiber, reviewed under crossed polarizers of a polarizing microscope.
Claim 2
Dependent Claim 129 words
A fiber of poly(p-phenyleneterephthalamide) characterized by having: a pulp-like short fiber form of about 2-100 μm in diameter and about 1,000-50,000 μm in length; irregular cross-sections in a plane taken perpendicular to the fiber length and needle point-like ends similar to those of natural wood pulp fibers; an inherent viscosity of at least 5.0 as measured at a concentration of 0.5 g of polymer in 100 ml of 97% concentrated sulfuric acid at 30° C.; a crystallinity of more than 50%, an orientation angle of less than 25°, and an apparent crystallite size of more than 50 Angstroms, based upon X-ray diffraction pattern data; and a cross-section with four extinction positions through 360° rotation of a cross-sectional specimen of said fiber, reviewed under crossed polarizers of a polarizing microscope.
Claim 3
Dependent Claim 13 words
The fiber of claim 1 wherein the inherent viscosity is up to 8.0.
Claim 4
Dependent Claim 13 words
The fiber of claim 2 wherein the inherent viscosity is at least 7.5.
Claim 5
Dependent Claim 14 words
The fiber of claim 1 wherein the inherent viscosity is from 6.0 to 8.0.
Claim 6
Dependent Claim 14 words
The fiber of claim 1 wherein the inherent viscosity is from 6.12 to 7.54.
Claim 7
Dependent Claim 18 words
The fiber of claim 1 wherein the fiber diameter is 2-12 μm and fiber length is 1,000-5,000 μm.
Claim 8
Dependent Claim 13 words
A plurality of the fibers of claim 1 formed into a sheet material.
Claim 9
Dependent Claim 14 words
A plurality of the fibers of claim 1 used as a heat resistant material.

References Cited (Backward Citations)

US3133138A Cited
US3671542A Cited
US3869430A Cited
US4048429A Cited
US4162346A Cited
JPS5427021A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-04-15 1988-10-15 1989-04-16 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-04-15 1992-10-15 1993-04-16 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-04-15 1996-10-15 1997-04-16 $7700.00 Window Closed / Lapsed

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