US4921656A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formation of melt-spun acrylic fibers which are particularly suited for thermal conversion to high strength carbon fibers
Assignee: BASF SE
•
Filing: 1988-08-25
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Granted: 1990-05-01
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Expires: 2008-08-25
Abstract
Abstract An acrylic multifilamentary material possessing an internal structure which is particularly suited for thermal conversion to high strength carbon fibers is formed via a specifically defined combination of processing conditions. The acrylic polymer while in substantially homogeneous admixture with appropriate concentrations (as defined) of acetonitrile, C 1 to C 4 monohydroxy alkanol, and water is melt extruded and is drawn at a relatively low draw ratio which is substantially less than the maximum draw ratio achievable. This fibrous material which is capable of readily undergoing drawing is passed through a heat treatment zone wherein the evolution of residual acetonitrile, the monohydroxy alkanol and water takes place. The resulting fibrous material following such heat treatment is subjected to additional drawing to accomplish further orientation and internal structure modification and to produce a fibrous material of the appropriate denier for carbon fiber production. One accordingly is provided a reliable route to form a fibrous acrylic precursor for carbon fiber production without the necessity to employ the solution-spinning routes commonly utilized in the prior art for precursor formation. One can now eliminate the utilization and handling of large amounts of solvent as has heretofore been necessary when forming an acrylic carbon fiber precursor. Also, arcylic fiber precursors possessing a wide variety of cross-sectional configurations now are made possible which can be thermally converted into carbon fibers of a similar cross-sectional configuration.
Inventors
- 👤 Gene P. Daumit
- 👤 Yoon S. Ko
- 👤 Christopher R. Slater
- 👤 Jozef G. Venner
- 👤 Chi C. Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:13
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/02; D01F6/18; D01D; D01D5/00; D01D5/08; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22
Claims Analysis
Total Claims: 84
Claim 1
Independent Claim
299 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers comprising: (a) forming at an elevated temperature a substantially homogeneous melt consisting essentially of (i) an acrylic polymer containing at least 85 weight percent of recurring acrylonitrile units, (ii) approximately 5 to 20 percent by weight of acetonitrile based upon said polymer, (iii) approximately 1 to 8 percent by weight of C 1 to C 4 monohydroxy alkanol based upon said polymer, and (iv) approximately 12 to 28 percent by weight of water based upon said polymer, (b) extruding said substantially homogeneous melt while at a temperature within the range of 140° to 190° C. through an extrusion orifice containing a plurality of openings into a filament-forming zone provided with a substantially non-reactive gaseous atmosphere provided at a temperature within the range of approximately 25° to 250° C. while under a longitudinal tension wherein substantial portions of said acetonitrile, monohydroxy alkanol, and water are evolved and an acrylic multifilamentary material is formed, (c) drawing said substantially homogeneous melt and acrylic multifilamentary material subsequent to passage through said extrusion orifice at a draw ratio of approximately 0.6 to 6.0:1, (d) passing said resulting acrylic multifilamentary material following steps (b) and (c) in the direction of its length through a heat treatment zone provided at a temperature of approximately 90° to 200° C. while at a relatively constant length wherein the evolution of substantially all of the residual acetonitrile, monohydroxy alkanol, and water present therein takes place, and (e) drawing said acrylic multifilamentary material resulting from step (d) while at an elevated temperature at a draw ratio of at least 3:1 to form an acrylic multifilamentary material having a mean single filament denier of approximately 0.3 to 5.0.
Claim 2
Dependent Claim
299 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers comprising: (a) forming at an elevated temperature a substantially homogeneous melt consisting essentially of (i) an acrylic polymer containing at least 85 weight percent of recurring acrylonitrile units, (ii) approximately 5 to 20 percent by weight of acetonitrile based upon said polymer, (iii) approximately 1 to 8 percent by weight of C 1 to C 4 monohydroxy alkanol based upon said polymer, and (iv) approximately 12 to 28 percent by weight of water based upon said polymer, (b) extruding said substantially homogeneous melt while at a temperature within the range of 140° to 190° C. through an extrusion orifice containing a plurality of openings into a filament-forming zone provided with a substantially non-reactive gaseous atmosphere provided at a temperature within the range of approximately 25° to 250° C. while under a longitudinal tension wherein substantial portions of said acetonitrile, monohydroxy alkanol, and water are evolved and an acrylic multifilamentary material is formed, (c) drawing said substantially homogeneous melt and acrylic multifilamentary material subsequent to passage through said extrusion orifice at a draw ratio of approximately 0.6 to 6.0:1, (d) passing said resulting acrylic multifilamentary material following steps (b) and (c) in the direction of its length through a heat treatment zone provided at a temperature of approximately 90° to 200° C. while at a relatively constant length wherein the evolution of substantially all of the residual acetonitrile, monohydroxy alkanol, and water present therein takes place, and (e) drawing said acrylic multifilamentary material resulting from step (d) while at an elevated temperature at a draw ratio of at least 3:1 to form an acrylic multifilamentary material having a mean single filament denier of approximately 0.3 to 5.0.
Claim 3
Dependent Claim
38 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according wherein said acrylic polymer contains at least 91 weight percent of recurring acrylonitrile units.
Claim 4
Dependent Claim
38 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according wherein said acrylic polymer contains at least 91 weight percent of recurring acrylonitrile units.
Claim 5
Dependent Claim
41 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said acrylic polymer contains 91 to 98 weight percent of recurring acrylonitrile units.
Claim 6
Dependent Claim
71 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said acrylic polymer includes recurring units derived from a member selected from the group consisting of methyl acrylate, methyl methacrylate, and mixtures thereof, and recurring units derived from a member selected from the group consisting of methacrylic acid, itaconic acid, and mixtures thereof.
Claim 7
Dependent Claim
94 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 4 wherein said acrylic polymer comprises 93 to 98 weight percent of recurring acrylonitrile units, approximately 1.7 to 6.5 weight percent of recurring units derived from a member selected from the group consisting of methyl acrylate, methyl methacrylate, and mixtures thereof, and approximately 0.3 to 2.0 weight percent of recurring units derived from a member selected from the group consisting of methacrylic acid, itaconic acid, and mixtures thereof.
Claim 8
Dependent Claim
55 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially homogeneous melt of step (a) contains approximately 72 to 80 percent by weight of said acrylic polymer based upon the total weight of the composition.
Claim 9
Dependent Claim
54 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said acetonitrile is provided in said substantially homogeneous melt in step (a) in a concentration of approximately 7 to 18 percent by weight of said polymer.
Claim 10
Dependent Claim
38 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said C 1 to C 4 monohydroxy alkanol is methanol.
Claim 11
Dependent Claim
60 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said C 1 to C 4 monohydroxy alkanol is provided in said substantially homogeneous melt in step (a) in a concentration of approximately 2 to 7 percent by weight of said polymer.
Claim 12
Dependent Claim
54 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said water is provided in said substantially homogeneous melt in step (a) in a concentration of approximately 15 to 23 percent by weight of said polymer.
Claim 13
Dependent Claim
43 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially homogeneous melt of step (a) additionally contains a minor concentration of a lubricant
Claim 14
Dependent Claim
39 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 11 wherein said lubricant is sodium stearate and said surfactant is sorbitan monolaurate.
Claim 15
Dependent Claim
47 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially homogeneous melt is at a temperature of approximately 160° to 185° C. when extruded in step (b).
Claim 16
Dependent Claim
53 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially homogeneous melt is at a temperature which exceeds the hydration and melting temperature by at least 15° C. when extruded in step (b).
Claim 17
Dependent Claim
53 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially homogeneous melt is at a temperature which exceeds the hydration and melting temperature by at least 20° C. when extruded in step (b).
Claim 18
Dependent Claim
52 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein during step (b) said extrusion orifice contains a plurality of substantially circular openings having diameters within the range of approximately 40 to 65 microns.
Claim 19
Dependent Claim
43 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein during step (b) said extrusion orifice contains a plurality of substantially uniform substantially non-circular openings.
Claim 20
Dependent Claim
57 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially non-reactive gaseous atmosphere of said filament-forming zone of step (b) is selected from the group consisting of air, steam, carbon dioxide, nitrogen, and mixtures of the foregoing.
Claim 21
Dependent Claim
51 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially non-reactive gaseous atmosphere of said filament-forming zone of step (b) is provided at a pressure of approximately 0 to 100 psig.
Claim 22
Dependent Claim
52 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially non-reactive gaseous atmosphere of said filament-forming zone of step (b) is provided at a superatmospheric pressure of approximately 10 to 50 psig.
Claim 23
Dependent Claim
53 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said substantially non-reactive gaseous atmosphere of said filament-forming zone of step (b) is provided at a temperature within the range of 90° to 200° C.
Claim 24
Dependent Claim
46 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said acrylic multifilamentary material is drawn at a draw ratio of approximately 0.8 to 5.0:1 during step (c).
Claim 25
Dependent Claim
39 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said drawing step (c) is carried out in said filament-forming zone.
Claim 26
Dependent Claim
64 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein a portion of said drawing of step (c) is carried out in said filament-forming zone simultaneously with said filament formation, and a portion of said drawing is carried out in at least one adjacent drawing zone.
Claim 27
Dependent Claim
48 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein at the conclusion of step (c) said acrylic multifilamentary material possesses a denier per filament of approximately 3 to 40.
Claim 28
Dependent Claim
54 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said acrylic multifilamentary material at the conclusion of step (c) possesses a substantially circular cross section and a denier to filament of approximately 3 to 12.
Claim 29
Dependent Claim
58 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said acrylic multifilamentary material at the conclusion of step (c) possesses filaments having a predetermined substantially uniform non-circular cross section and a denier per filament of approximately 6 to 40.
Claim 30
Dependent Claim
46 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said heat treatment zone of step (d) is provided at a temperature of approximately 110° to 175° C.
Claim 31
Dependent Claim
47 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein during step (d) said acrylic multifilamentary material comes in contact with the surface of at least one heated roller.
Claim 32
Dependent Claim
46 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein during step (d) said acrylic multifilamentary material comes in contact with the drums of a suction drum drier.
Claim 33
Dependent Claim
60 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein at the conclusion of step (d) said acrylic multifilamentary material contains less than 2.0 percent by weight of acetonitrile, C 1 to C 4 monohydroxy alkanol and water based upon said polymer.
Claim 34
Dependent Claim
60 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein at the conclusion of step (d) said acrylic multifilamentary material contains less than 1.0 percent by weight of acetonitrile, C 1 to C 4 monohydroxy alkanol and water based upon said polymer.
Claim 35
Dependent Claim
47 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein during step (e) said resulting acrylic multifilamentary material is drawn at a draw ratio of approximately 4 to 10:1.
Claim 36
Dependent Claim
42 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said drawing of step (e) is carried out in an atmosphere which contains steam.
Claim 37
Dependent Claim
47 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein said drawing of step (e) is carried out in steam at a pressure of approximately 10 to 30 psig.
Claim 38
Dependent Claim
59 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 34 wherein prior to said drawing of step (e) said acrylic multifilamentary material is conditioned by passage while at a substantially constant length through an atmosphere containing hot water, steam, or mixtures thereof.
Claim 39
Dependent Claim
53 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 35 wherein prior to drawing in step (e) said acrylic multifilamentary material is conditioned by passage while at a substantially constant length through an atmosphere containing steam.
Claim 40
Dependent Claim
58 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein following said drawing of step (e) said acrylic multifilamentary material consists of filaments having substantially uniform substantially circular cross sections and a denier per filament of approximately 0.3 to 1.5.
Claim 41
Dependent Claim
58 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein following said drawing of step (e) said acrylic multifilamentary material consists of filaments having substantially uniform substantially circular cross sections and a denier per filament of approximately 0.5 to 1.2.
Claim 42
Dependent Claim
62 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein following said drawing of step (e) said acrylic multifilamentary material possesses filaments having predetermined substantially uniform non-circular cross sections wherein the closest surface from all internal locations is less than 8 microns in distance.
Claim 43
Dependent Claim
45 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein following said drawing step (e) said acrylic multifilamentary material comprises filaments having substantially uniform crescent-shaped cross sections.
Claim 44
Dependent Claim
51 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein following said drawing of step (e) said acrylic multifilamentary material comprises filaments having substantially uniform multi-lobed cross sections of at least three lobes.
Claim 45
Dependent Claim
52 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein following said drawing of step (e) said acrylic multifilamentary material possesses a mean single filament tensile strength of at least 5.0 grams per denier.
Claim 46
Dependent Claim
52 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein following said drawing of step (e) said acrylic multifilamentary material possesses a mean single filament tensile strength of at least 6.0 grams per denier.
Claim 47
Dependent Claim
61 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein the product of step (e) upon thermal stabilization and carbonization is capable of yielding carbon fibers having a substantially circular cross section and an impregnated strand tensile strength of at least 450,000 psi.
Claim 48
Dependent Claim
61 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein the product of step (e) following thermal stabilization and carbonization is capable of yielding carbon fibers having a substantially circular cross section and an impregnated strand tensile strength of at least 500,000 psi.
Claim 49
Dependent Claim
63 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 1 wherein the product of step (e) upon thermal stabilization and carbonization is capable of yielding carbon fibers having a predetermined substantially uniform non-circular cross section and an impregnated strand tensile strength of at least 350,000 psi.
Claim 50
Dependent Claim
343 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers comprising: (a) forming at an elevated temperature a substantially homogeneous melt consisting essentially of (i) an acrylic polymer containing at least 91 weight percent of recurring acrylonitrile units, (ii) approximately 7 to 18 percent by weight of acetonitrile based upon said polymer, (iii) approximately 2 to 7 percent by weight of methanol based upon said polymer, and (iv) approximately 15 to 23 percent by weight of water based upon said polymer, with the proviso that the said acrylic polymer is present in a concentration of approximately 72 to 80 percent by weight based upon the total weight of the melt, (b) extruding said substantially homogeneous melt while at a temperature within the range of 160° to 185° C. which exceeds the hydration and melting temperature by at least 15° C. through an extrusion orifice containing a plurality of openings into a filament-forming zone provided with a substantially non-reactive gaseous atmosphere at a pressure of approximately 10 to 50 psig provided at a temperature within the range of approximately 90° to 200° C. while under a longitudinal tension wherein substantial portions of said acetonitrile, methanol, and water are evolved and an acrylic multifilamentary material is formed, (c) drawing said substantially homogeneous melt and acrylic multifilamentary material subsequent to passage through said extrusion orifice at a draw ratio of approximately 0.8 to 5.0:1, (d) passing said resulting acrylic multifilamentary material following steps (b) and (c) in the direction of its length through a heat treatment zone provided at a temperature of approximately 110° to 175° C. while at a relatively constant length wherein the evolution of substantially all of the residual acetonitrile, methanol, and water present therein takes place, and (e) drawing said acrylic multifilamentary material 1 resulting from step (d) while at an elevated temperature at a draw ratio of approximately 4 to 10:1 to form an acrylic multifilamentary material having a mean single filament denier of approximately 0.3 to 5.0.
Claim 51
Dependent Claim
343 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers comprising: (a) forming at an elevated temperature a substantially homogeneous melt consisting essentially of (i) an acrylic polymer containing at least 91 weight percent of recurring acrylonitrile units, (ii) approximately 7 to 18 percent by weight of acetonitrile based upon said polymer, (iii) approximately 2 to 7 percent by weight of methanol based upon said polymer, and (iv) approximately 15 to 23 percent by weight of water based upon said polymer, with the proviso that the said acrylic polymer is present in a concentration of approximately 72 to 80 percent by weight based upon the total weight of the melt, (b) extruding said substantially homogeneous melt while at a temperature within the range of 160° to 185° C. which exceeds the hydration and melting temperature by at least 15° C. through an extrusion orifice containing a plurality of openings into a filament-forming zone provided with a substantially non-reactive gaseous atmosphere at a pressure of approximately 10 to 50 psig provided at a temperature within the range of approximately 90° to 200° C. while under a longitudinal tension wherein substantial portions of said acetonitrile, methanol, and water are evolved and an acrylic multifilamentary material is formed, (c) drawing said substantially homogeneous melt and acrylic multifilamentary material subsequent to passage through said extrusion orifice at a draw ratio of approximately 0.8 to 5.0:1, (d) passing said resulting acrylic multifilamentary material following steps (b) and (c) in the direction of its length through a heat treatment zone provided at a temperature of approximately 110° to 175° C. while at a relatively constant length wherein the evolution of substantially all of the residual acetonitrile, methanol, and water present therein takes place, and (e) drawing said acrylic multifilamentary material 1 resulting from step (d) while at an elevated temperature at a draw ratio of approximately 4 to 10:1 to form an acrylic multifilamentary material having a mean single filament denier of approximately 0.3 to 5.0.
Claim 52
Dependent Claim
41 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48, wherein said acrylic polymer contains 91 to 98 weight percent of recurring acrylonitrile units.
Claim 53
Dependent Claim
70 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal, conversion to high strength carbon fibers according to claim wherein said acrylic polymer includes recurring units derived from a member selected from the group consisting of methyl acrylate, methyl methacrylate, and mixtures thereof, and recurring units derived from a member selected from the group consisting of methacrylic acid, itaconic acid, and mixtures thereof.
Claim 54
Dependent Claim
94 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 50 wherein said acrylic polymer comprises 93 to 98 weight percent of recurring acrylonitrile units, approximately 1.7 to 6.5 weight percent of recurring units derived from a member selected from the group consisting of methyl acrylate, methyl methacrylate, and mixtures thereof, and approximately 0.3 to 2.0 weight percent of recurring units derived from a member selected from the group consisting of methacrylic acid, itaconic acid, and mixtures thereof.
Claim 55
Dependent Claim
59 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein the substantially homogeneous melt formed in step (a) comprises said acrylic polymer in a concentration of approximately 74 to 80 percent by weight based upon the total weight of the melt.
Claim 56
Dependent Claim
50 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein said substantially homogeneous melt of step (a) additionally contains a minor concentration of a lubricant and a minor concentration of a surfactant.
Claim 57
Dependent Claim
39 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 53 wherein said lubricant is sodium stearate and said surfactant is sorbitan monolaurate.
Claim 58
Dependent Claim
53 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein said substantially homogeneous melt is at a temperature which exceeds the hydration and melting temperature by at least 20° C. when extruded in step (b).
Claim 59
Dependent Claim
54 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein during step (b) said extrusion orifice contains a plurality of substantially uniform substantially circular openings having diameters within the range of approximately 40 to 65 microns.
Claim 60
Dependent Claim
43 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein during step (b) said extrusion orifice contains a plurality of substantially uniform substantially non-circular openings.
Claim 61
Dependent Claim
53 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein said substantially non-reactive gaseous atmosphere of step (b) is selected from the group consisting of air, steam, carbon dioxide, nitrogen, and mixtures of the foregoing.
Claim 62
Dependent Claim
39 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein said drawing step (c) is carried out in said filament-forming zone.
Claim 63
Dependent Claim
64 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal, conversion to high strength carbon fibers according to claim 48 wherein a portion of said drawing of step (c) is carried out in said filament-forming zone simultaneously with said filament formation, and a portion of said drawing is carried out in at least one adjacent drawing zone.
Claim 64
Dependent Claim
48 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein at the conclusion of step (c) said acrylic multifilamentary material possesses a denier per filament of approximately 3 to 40.
Claim 65
Dependent Claim
54 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal, conversion to high strength carbon fibers according to claim 48 wherein said acrylic multifilamentary material at the conclusion of step (c) possesses a substantially circular cross section and a denier per filament of approximately 3 to 12.
Claim 66
Dependent Claim
58 words
An improved process for the formation of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein said acrylic multifilamentary material at the conclusion of step (c) possesses filaments having a predetermined substantially uniform non-circular cross section and a denier per filament of approximately 6 to 40.
Claim 67
Dependent Claim
47 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein during step (d) said acrylic multifilamentary material comes in contact with the surface of at least one heated roller.
Claim 68
Dependent Claim
46 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal, conversion to high strength carbon fibers according to claim 48 wherein during step (d) said acrylic multifilamentary material comes in contact with the drums of a suction drum drier.
Claim 69
Dependent Claim
56 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 at the conclusion of step (d) said acrylic multifilamentary material contains less than 2.0 percent by weight of acetonitrile, methanol, and water based upon the weight of said polymer.
Claim 70
Dependent Claim
57 words
An improved process for the production of an acrylic filamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein at the conclusion of step (d) said acrylic multifilamentary material contains less than 1.0 percent by weight of acetonitrile, methanol, and water based upon the weight of said polymer.
Claim 71
Dependent Claim
42 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal, conversion to high strength carbon fibers according to claim 48 wherein said drawing of step (e) is carried out in an atmosphere which contains steam.
Claim 72
Dependent Claim
47 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein said drawing of step (e) is carried out in steam at a pressure of approximately 10 to 30 psig.
Claim 73
Dependent Claim
59 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 68 wherein prior to said drawing of step (e) said acrylic multifilamentary material is conditioned by passage while at a substantially constant length through an atmosphere containing hot water, steam, or mixtures thereof.
Claim 74
Dependent Claim
53 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 69 wherein prior to drawing in step (e) said acrylic multifilamentary material is conditioned by passage while at a substantially constant length through an atmosphere containing steam.
Claim 75
Dependent Claim
54 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein following said drawing of step (e) said acrylic multifilamentary material possesses a substantially circular cross section and a denier per filament of approximately 0.3 to 1.5.
Claim 76
Dependent Claim
56 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein following said drawing of step (e) said acrylic multifilamentary material comprises filaments having a substantially circular cross section and a denier per filament of approximately 0.5 to 1.2.
Claim 77
Dependent Claim
64 words
An improved process for the production of an acrylic multifilamentary material which in particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein following said drawing of step (e) said acrylic multifilamentary material comprises filaments having a predetermined substantially uniform non-circular cross section wherein the closest filament surface from all internal locations is less than 6 microns in distance.
Claim 78
Dependent Claim
45 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein following said drawing step (e) said acrylic multifilamentary material comprises filaments having substantially uniform crescent-shaped cross sections.
Claim 79
Dependent Claim
50 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein following said drawing of step (e) said acrylic multifilamentary material comprises filaments having substantially uniform multi-lobed cross-sections of at least three lobes.
Claim 80
Dependent Claim
52 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein following said drawing of step (e) said acrylic multifilamentary material possesses a mean single filament tensile strength of at least 5.0 grams per denier.
Claim 81
Dependent Claim
52 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein following said drawing of step (e) said acrylic multifilamentary material possesses a mean single filament tensile strength of at least 6.0 grams per denier.
Claim 82
Dependent Claim
61 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein the product of step (e) upon thermal stabilization and carbonization is capable of yielding carbon fibers having a substantially circular cross section and an impregnated strand tensile strength of at least 450,000 psi.
Claim 83
Dependent Claim
61 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein the product of step (e) upon thermal stabilization and carbonization is capable of yielding carbon fibers having a substantially circular cross section and an impregnated strand tensile strength of at least 500,000 psi.
Claim 84
Dependent Claim
63 words
An improved process for the production of an acrylic multifilamentary material which is particularly suited for thermal conversion to high strength carbon fibers according to claim 48 wherein the product of step (e) upon thermal stabilization and carbonization is capable of yielding carbon fibers having a predetermined substantially uniform non-circular cross section and an impregnated strand tensile strength of at least 350,000 psi.
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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) | 1993-04-30 | 1993-10-30 | 1994-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-30 | 1997-10-30 | 1998-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-30 | 2001-10-30 | 2002-05-01 | $7700.00 | Window Closed / Lapsed |