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US5227237A
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Noncircular cross-section carbon fiber, process for producing the same and composite of the carbon fiber with resin
Assignee: Toray Industries Inc
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Filing: 1990-08-31
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Granted: 1993-07-13
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Expires: 2010-08-31
Abstract
Abstract A noncircular cross-section carbon fiber wherein the cross-section is a noncircular one having at least one plane of symmetry passing the centroid and having an angle of rotational symmetry, θ, defined by θ=360°/n, in which n is an integer of 1 to 10; wherein the internal structure has no lamellar structure and the fiber has a substantially uniform crystalline structure; and wherein the fiber surface has a surface smoothness S of 1.16 or below and the tensile strength and the tensile modulus of the fiber in the form of a resin-impregnated strand is 300 kg/mm 2 or above and 20 ton/mm 2 or above, respectively; a process for producing such carbon fiber; and a composite of such carbon fiber with a resin.
Inventors
- 👤 Hideo Saruyama
- 👤 Akira Okuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:00
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; D01D; D01D5/00; D01D5/253; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T428/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
103 words
A noncircular cross-section carbon fiber, comprising a noncircular cross-section having at least one plane of symmetry passing its centroid and having an angle θ of rotational symmetry defined by θ=360°/n, in which n is an integer of 1 to 10; wherein an internal structure has no lamellar structure and said fiber has a substantially homogeneous crystalline structure; wherein a surface smoothness S of a fiber surface is 1.16 or below; and wherein a tensile strength and a tensile modulus of the carbon fiber in the form of a resin-impregnated strand are 300 kg/mm 2 or above and 20 ton/mm 2 or above, respectively.
Claim 2
Dependent Claim
103 words
A noncircular cross-section carbon fiber, comprising a noncircular cross-section having at least one plane of symmetry passing its centroid and having an angle θ of rotational symmetry defined by θ=360°/n, in which n is an integer of 1 to 10; wherein an internal structure has no lamellar structure and said fiber has a substantially homogeneous crystalline structure; wherein a surface smoothness S of a fiber surface is 1.16 or below; and wherein a tensile strength and a tensile modulus of the carbon fiber in the form of a resin-impregnated strand are 300 kg/mm 2 or above and 20 ton/mm 2 or above, respectively.
Claim 3
Dependent Claim
33 words
A carbon fiber according to claim 1, wherein the value of n which defines the angle of rotational symmetry θ=360°/n of the cross-section of the fiber is an integer of 1 to 5.
Claim 4
Dependent Claim
47 words
A carbon fiber according to claim 1, wherein a degree D of deformation defined by a ratio R/r, wherein R is the radius of the circumscribed circle of the cross-section of the fiber and r is the radius of the inscribed circle thereof, is 1.1 to 7.0.
Claim 5
Dependent Claim
47 words
A carbon fiber according to claim 1, wherein a degree D of deformation defined by a ratio R/r, wherein R is the radius of the circumscribed circle of the cross-section of the fiber and r is the radius of the inscribed circle thereof, is 1.2 to 6.0.
Claim 6
Dependent Claim
39 words
A carbon fiber according to claim 1, wherein the the tensile strength and the tensile modulus of the fiber in the form of a resin-impregnated strand is 320 kg/mm 2 or above and 22 ton/mm 2 or above, respectively.
Claim 7
Dependent Claim
12 words
A composite comprising the carbon fiber of claim 1 and a resin.
Claim 8
Dependent Claim
144 words
A process for producing a noncircular cross-section carbon fiber, comprising spinning a dope comprising an acrylonitrile polymer and an oxidation promoting vinyl monomer containing at least 95 mol % of acrylonitrile and a solvent for said polymer through a spinneret having noncircular cross-section holes temporarily into air or an inert gas atmosphere and immersing the spun dope in a coagulation bath comprising said solvent and a coagulant immediately after the spinning, followed by washing with water and drawing, thereby making fiber having a cross-section which is a noncircular one having at least one plane of symmetry passing its centroid and having an angle θ of rotational symmetry defined by θ=360°/n, wherein n is an integer of 1 to 10, oxidizing said fiber as a precursor, a fineness of the precursor being 0.3 to 1.5 denier, and carbonizing the oxidized precursor into a carbon fiber.
Claim 9
Dependent Claim
144 words
A process for producing a noncircular cross-section carbon fiber, comprising spinning a dope comprising an acrylonitrile polymer and an oxidation promoting vinyl monomer containing at least 95 mol % of acrylonitrile and a solvent for said polymer through a spinneret having noncircular cross-section holes temporarily into air or an inert gas atmosphere and immersing the spun dope in a coagulation bath comprising said solvent and a coagulant immediately after the spinning, followed by washing with water and drawing, thereby making fiber having a cross-section which is a noncircular one having at least one plane of symmetry passing its centroid and having an angle θ of rotational symmetry defined by θ=360°/n, wherein n is an integer of 1 to 10, oxidizing said fiber as a precursor, a fineness of the precursor being 0.3 to 1.5 denier, and carbonizing the oxidized precursor into a carbon fiber.
Claim 10
Dependent Claim
31 words
A process according to claim 7, wherein the acrylonitrile polymer is a copolymer comprising 98 mol % or above of acrylonitrile and 2 mol % or below of a vinyl monomer.
Claim 11
Dependent Claim
29 words
A process according to claim 7, wherein n which defines said angle θ of rotational symmetry of the cross-section of the fiber is an integer of 1 to 5.
Claim 12
Dependent Claim
18 words
A process according to claim 7, wherein a single-filament fineness of the precursor is 0.1 to 2.5 denier.
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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) | 1996-07-12 | 1997-01-11 | 1997-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-12 | 2001-01-11 | 2001-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-12 | 2005-01-11 | 2005-07-13 | $7700.00 | Window Closed / Lapsed |