US3969268A
Expired / Lapsed
US
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Process for preparing active carbon fibers
Assignee: Toyobo Co Ltd
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Filing: 1974-12-31
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Granted: 1976-07-13
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Expires: 1994-12-31
Abstract
Abstract A process for preparing active carbon fibers which comprises (a) providing a cellulose fiber with a phosphorus compound reactive thereto, (b) subjecting the resulting fiber to heat treatment at about 200° to 350°C until the decreased percentage of fiber becomes about 40 to 75 % (W/W) and then (c) subjecting the resultant fiber to activation treatment at about 450° to 1000°C in an atmosphere containing not less than about 5 % (V/V) of steam until the decreased percentage of fiber becomes about 65 to 95 % (W/W), the said phosphorus compound showing a residual percentage of phosphorus of not less than about 70 % (W/W) after the heat treatment of the step (b) and a residual percentage of phosphorus of not more than about 10 % (W/W) after the activation treatment of the step (c).
Inventors
- 👤 Takashi Fukuda
- 👤 Nobuo Ishizaki
- 👤 Shoichi Iwahori
- 👤 Masayoshi Shimada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:22
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/28023; D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/16
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
135 words
A process for preparing active carbon fibers which comprises (a) providing a cellulose fiber with a phosphorus compound reactive thereto, (b) subjecting the resulting fiber to heat treatment at about 200° to 350°C until the decreased percentage of fiber becomes about 40 to 75 % (W/W) and then (c) subjecting the resultant fiber to activation treatment at about 450° to 1000°C in an atmosphere containing not less than about 5 % (V/V) of steam until the decreased percentage of fiber becomes about 65 to 95 % (W/W), the said phosphorous compound showing a residual percentage of phosphorus of not less than about 70 % (W/W) after the heat treatment of the step (b) and a residual percentage of phosphorus of not more than about 10 % (W/W) after the activation treatment of the step (c).
Claim 2
Dependent Claim
135 words
A process for preparing active carbon fibers which comprises (a) providing a cellulose fiber with a phosphorus compound reactive thereto, (b) subjecting the resulting fiber to heat treatment at about 200° to 350°C until the decreased percentage of fiber becomes about 40 to 75 % (W/W) and then (c) subjecting the resultant fiber to activation treatment at about 450° to 1000°C in an atmosphere containing not less than about 5 % (V/V) of steam until the decreased percentage of fiber becomes about 65 to 95 % (W/W), the said phosphorous compound showing a residual percentage of phosphorus of not less than about 70 % (W/W) after the heat treatment of the step (b) and a residual percentage of phosphorus of not more than about 10 % (W/W) after the activation treatment of the step (c).
Claim 3
Dependent Claim
35 words
The process according to claim 1, wherein the phosphorus compound is an oxy acid of phosphorus or an ester or salt thereof, a polyphosphate, a polyphosphonate, a phosphine, a phosphine oxide or a phosphonium salt.
Claim 4
Dependent Claim
51 words
The process according to claim 2, wherein the phosphorus compound is a polyphosphate of the formula: ##EQU3## wherein R is a monovalent hydrocarbon residue having 1 to 18 carbon atoms, R' is a divalent hydrocarbon residue having 1 to 18 carbon atoms and n is an integer of 3 or more.
Claim 5
Dependent Claim
54 words
The process according to claim 2, wherein the phosphorus compound is a polyphosphate of either one of the formulae: ##EQU4## wherein R is a monovalent hydrocarbon residue having 1 to 18 carbon atoms, R' is a divalent hydrocarbon residue having 1 to 18 carbon atoms and n is an integer of 3 or more.
Claim 6
Dependent Claim
25 words
The process according to claim 1, wherein the phosphorus compound is provided to the fiber in an amount of about 0.5 to 20 % (W/W).
Claim 7
Dependent Claim
25 words
The process according to claim 5, wherein the phosphorus compound is provided to the fiber in an amount of about 2 to 10 % (W/W).
Claim 8
Dependent Claim
18 words
The process according to claim 1, wherein the phosphorus compound is provided in the form of a solution.
Claim 9
Dependent Claim
26 words
The process according to claim 7, wherein the solution is an aqueous solution containing the phosphorus compound in a concentration of 3 to 60 % (W/W).
Claim 10
Dependent Claim
15 words
The process according to claim 1, wherein the fiber is provided with a nitrogen-containing compound.
Claim 11
Dependent Claim
20 words
The process according to claim 9, wherein the nitrogen-containing compound has a boiling point of not less than about 100°C.
Claim 12
Dependent Claim
59 words
The process according to claim 9, wherein the nitrogen-containing compound is ammonium hydroxide, an ammonium salt of an organic or inorganic acid, urea, thiourea, an amine having a boiling point of not less than about 100°C or a compound having a urethane bond, an amide bond or a urea bond and a molecular weight of not less than 200.
Claim 13
Dependent Claim
17 words
The process according to claim 9, wherein the nitrogen-containing compound is the same as the phosphorus compound.
Claim 14
Dependent Claim
32 words
The process according to claim 12, wherein the nitrogen-containing compound is an ammonium salt of an oxy acid of phosphorus or a condensation product of an oxy acid of phosphorus with urea.
Claim 15
Dependent Claim
29 words
The process according to claim 9, wherein the proportion of the nitrogen-containing compound as nitrogen and the phosphorus compound as phosphorus is 0.1 - 5.0 : 1 by weight.
Claim 16
Dependent Claim
29 words
The process according to claim 1, wherein the heat treatment is carried out in an atmosphere comprising a combustion gas of a hydrocarbon having 1 to 6 carbon atoms.
Claim 17
Dependent Claim
18 words
The process according to claim 15, wherein the hydrocarbon is methane, ethane, propane, butane, heptane, ethylene or butylene.
Claim 18
Dependent Claim
25 words
The process according to claim 15, wherein the treatment is carried out until the decreased percentage of fiber becomes about 45 to 65 % (W/W).
Claim 19
Dependent Claim
25 words
The process according to claim 1, wherein the activation treatment is carried out in an atmosphere containing about 10 to 70 % (V/V) of steam.
Claim 20
Dependent Claim
25 words
The process according to claim 18, wherein the treatment is carried out until the decreased percentage of fiber becomes about 70 to 90 % (W/W).
Claim 21
Dependent Claim
12 words
The process according to claim 3, wherein R is substituted with halogen.
Claim 22
Dependent Claim
12 words
The process according to claim 3, wherein R' is substituted with halogen.
Claim 23
Dependent Claim
12 words
The process according to claim 4, wherein R is substituted with halogen.
Claim 24
Dependent Claim
12 words
The process according to claim 4, wherein R' is substituted with halogen.
References Cited (Backward Citations)
US1819165A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |