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US3972968A Expired / Lapsed US ⏱️ 0.0 years remaining

Use of hot buoyant liquid to convert pitch to continuous carbon filament

Assignee: Sunoco Inc R&M
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Filing: 1974-11-21
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Granted: 1976-08-03
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Expires: 1994-11-21
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Abstract

Abstract Suitable pitch is formed into a filament continuously and upward by various means located at the bottom of a vessel containing a hot buoyant liquid. The liquid buoys up the fragile filament as it ascends the vessel from a lower region held at one temperature to an upper region where the temperature is about 450°-700°C. The filament emerges upward out of the liquid to move further through a still higher temperature (>900°C) zone which upon leaving the previously formed pitch is a carbon filament. The liquid can be a blend of suitable molten inorganic salts or a molten inorganic oxide.

Inventors

  • 👤 Edward M. Kohn

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 03:57
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/145; Y; Y10; Y10S; Y10S264/00; Y10S264/19

Claims Analysis

Total Claims: 29
Claim 1
Independent Claim 179 words
A process for producing continuous carbon filaments comprising: a. forming at least one stream of molten carbon forming pitch wherein resulting formed molten pitch is in contact with a liquid selected from a group consisting of a blend of molten inorganic salts and molten inorganic oxide; b. passing the formed molten pitch stream generally vertically upward through the liquid which is maintained within a temperature range wherein the pitch forms a continuous stream; c. continuing the generally vertically upward passage of the stream of formed molten pitch through a second liquid layer maintained between a temperature of about 450°-700° C and wherein the second liquid layer is in direct contact with the first liquid layer and both layers are composed of the same material and upon leaving the second liquid layer the pitch's hydrogen content is substantially reduced; and d. after the formed pitch leaves the second liquid layer it enters an inert atmosphere maintained at a temperature in excess of about 900°-1000° C and upon leaving the inert atmosphere the previously formed pitch stream is a carbon filament.
Claim 2
Dependent Claim 179 words
A process for producing continuous carbon filaments comprising: a. forming at least one stream of molten carbon forming pitch wherein resulting formed molten pitch is in contact with a liquid selected from a group consisting of a blend of molten inorganic salts and molten inorganic oxide; b. passing the formed molten pitch stream generally vertically upward through the liquid which is maintained within a temperature range wherein the pitch forms a continuous stream; c. continuing the generally vertically upward passage of the stream of formed molten pitch through a second liquid layer maintained between a temperature of about 450°-700° C and wherein the second liquid layer is in direct contact with the first liquid layer and both layers are composed of the same material and upon leaving the second liquid layer the pitch's hydrogen content is substantially reduced; and d. after the formed pitch leaves the second liquid layer it enters an inert atmosphere maintained at a temperature in excess of about 900°-1000° C and upon leaving the inert atmosphere the previously formed pitch stream is a carbon filament.
Claim 3
Dependent Claim 26 words
Process according to claim 1 wherein the liquid has a melting point below about 375° C and a boiling point in excess of about 750° C.
Claim 4
Dependent Claim 12 words
Process according to claim 2 wherein the liquid is a LiCl/KCl eutectic.
Claim 5
Dependent Claim 31 words
Process according to claim 1 wherein the temperature of (d) is in excess of 2000° C and upon leaving the inert atmosphere the previously formed pitch stream is a graphite filament.
Claim 6
Dependent Claim 21 words
Process according to claim 1 wherein the carbon forming pitch contains a carbon to hydrogen atomic ratio of greater than 1.55.
Claim 7
Dependent Claim 20 words
Process according to claim 5 wherein the pitch is selected from the group consisting of petroleum pitch and coal pitch.
Claim 8
Dependent Claim 19 words
Process according to claim 6 wherein the pitch has a softening point within the range of about 150°-400° C.
Claim 9
Dependent Claim 26 words
Process according to claim 7 wherein the liquid has a melting point below about 375° C and a boiling point in excess of about 750° C.
Claim 10
Dependent Claim 12 words
Process according to claim 8 wherein the liquid is a LiCl/KCl eutectic.
Claim 11
Dependent Claim 31 words
Process according to claim 9 wherein the temperature of (d) is in excess of 2000° C and upon leaving the inert atmosphere the previously formed pitch stream is a graphite filament.
Claim 12
Dependent Claim 15 words
Process according to claim 1 wherein the temperature of (b) is between about 150°-500° C.
Claim 13
Dependent Claim 24 words
Process according to claim 11 wherein the pitch upon leaving the second liquid layer contains a carbon to hydrogen atomic ratio greater than 1.88.
Claim 14
Dependent Claim 21 words
Process according to claim 12 wherein the time of contacting of (d) is sufficient to remove most of the remaining hydrogen.
Claim 15
Dependent Claim 20 words
Process according to claim 13 wherein the carbon contained in the carbon filament is greater than about 95 weight percent.
Claim 16
Dependent Claim 21 words
Process according to claim 14 wherein the carbon forming pitch contains a carbon to hydrogen atomic ratio of greater than 1.55.
Claim 17
Dependent Claim 20 words
Process according to claim 15 wherein the pitch is selected from the group consisting of petroleum pitch and coal pitch.
Claim 18
Dependent Claim 19 words
Process according to claim 16 wherein the pitch has a softening point within the range of about 150°-400° C.
Claim 19
Dependent Claim 26 words
Process according to claim 16 wherein the liquid has a melting point below about 375° C and a boiling point in excess of about 750° C.
Claim 20
Dependent Claim 12 words
Process according to claim 18 wherein the liquid is a LiCl/KCl eutectic.
Claim 21
Dependent Claim 30 words
Process according to claim 1 wherein after the carbon filament is obtained, the filament is subject to an elevated temperature for a sufficient time to convert the carbon into graphite.
Claim 22
Dependent Claim 15 words
Process according to claim 20 wherein the elevated temperature is in excess of 2000° C.
Claim 23
Dependent Claim 15 words
Process according to claim 21 wherein the temperature of (b) is between about 150°-500° C.
Claim 24
Dependent Claim 27 words
Process according to claim 22 wherein the time of contacting at said temperature range of (c) is sufficient to substantially reduce the hydrogen content of the pitch.
Claim 25
Dependent Claim 24 words
Process according to claim 23 wherein the pitch upon leaving the second liquid layer contains a carbon to hydrogen atomic ratio greater than 1.88.
Claim 26
Dependent Claim 21 words
Process according to claim 24 wherein the time of contacting of (d) is sufficient to remove most of the remaining hydrogen.
Claim 27
Dependent Claim 20 words
Process according to claim 25 wherein the carbon contained in the carbon filament is greater than about 95 weight percent.
Claim 28
Dependent Claim 23 words
Process according to claim 26 wherein the filament after subjected to the elevated temperature contains more than about 99 weight percent of carbon.
Claim 29
Dependent Claim 11 words
Process according to claim 27 wherein the carbon is essentially graphite.

References Cited (Backward Citations)

US3461197A Cited
US3508871A Cited
US3347959A Cited
US3448185A Cited
US3595946A Cited
US3755526A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1979-08-03 1980-02-02 1980-08-03 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1983-08-03 1984-02-02 1984-08-03 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1987-08-03 1988-02-02 1988-08-03 $7700.00 Window Closed / Lapsed

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