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Publication numberUS3053775 A
Publication typeGrant
Publication dateSep 11, 1962
Filing dateNov 12, 1959
Priority dateNov 12, 1959
Publication numberUS 3053775 A, US 3053775A, US-A-3053775, US3053775 A, US3053775A
InventorsWilliam F Abbott
Original AssigneeCarbon Wool Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method for carbonizing fibers
US 3053775 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

Sept. 115 1962 w, F. ABBOTT METHOD FOR CARBONIZING FIBERS Filed Nov. l2, 1959 l//LL//JM ,055077 INVENToR.

o-W 54X 706/145' VS United States Parent fornia i t Filed Nov.` 1 2', 1959, Ser. No. 852,580 8 Claims. (Cl. 252-421) This applicationisV a' continuation-impart of my prior, co-pending application Serial No. 569,391, filed March 5, 1956, entitled Method for Carbonizing Fibers, and Articles Produced Therefrom, now abandoned.

This' invention relates to Vfibrous materials and has particular reference to a process for carbonizing fibers and to articles produced therefrom.

One of the primary objects of this invention is to provide a process for the production of carbon in fibrous formv having a highV intrinsic liber density and good tensile strength. While fibers of carbon are not basically new, carbon fibers heretofore produced have been so weak in structure that they could not resist even slight mechanical forces without breakage or disintegration. The present invention provides for the first time bers substantially of car-bon which are su'fiiciently strong to retain theiriibrous form upon being subjected to mechanical forces.

Another object of this invention is to provide a hard, high density carbon in the form of tine fibers, the fibers being clean and' strong because of the high density, yet flexible and resilient due to the small diameter of the fibers.

Another object of this invention is to provide a process for the production of carbon fibers having a wide rangel ofiber diameter and other characteristics for use in varied specific applications.

Another object of this invention is to provide a carbon fiber which is capable of being activated to `a high level While -still .retaining 4a considerable part of its original strength, the activated fiber having adsorption characteristics equal on a weight basis to conventional activated carbon in granular form. Granular activated carbon is Well knownjin industrial applications, but is limited to use' applications' which provide means to contain the carbon granules. Activated carbonfibers of the present invention e'xtendthe use of carbon to clothing, masks, andiilters of fiber construction.

Other objects and advantages ofthe invention,` it is believed, will be readily apparent 4from the following detailed description o f preferred embodiments thereof when readin connection with the accompanying drawings.

In the drawings:

The single FlGURE is a diagrammatic view illustrating the apparatus required to carry out the process of this invention on a small scale.

Briefly, this invention comprehends within its scope the discovery that certain synthetic fibers may Ibe car-4 bonized by carefully controlled thermal decomposition to produce a dense, strong carbon fiber, The choice of rawmaten'als is limited to synthetic fibers of the nonthermoplastic type, which do nottend to melt or how on heating and hence retain the fibrous form when heated to the ldecomposition point.

Natural fibers, `such as cotton, for example, are not suitablefor the purpose of this invention. Although such fibers may be carbonized, they are weakand therefore are unsatisfactory for practical use in the form of carbon fibers.

lthas been found that a regenerated cellulose fiber, such as viscose rayon, cuprammnium rayon and'saponified acetate rayon, is a particularly suitable raw Amaterial foi accomplishing the endsofwthepresent invention.

HCC

The present process comprises heating' the raw fiber material in an inert, oxygenfree atmosphere to a temperature suiciently high to bring about substantially complete Vthermal decomposition of the non-carbon corrstituents ofthe material, great care being taken to confL trol the rate of temperature risesiohthat gasificaticn is slow to prevent fiber rupture by rapid dec'ompos'itiri.`

4It has been discovered that a critical temperature f angfel of from about 250 to about 5002" E ex'ists for thedej sired carbonization of the raw regenerated cellulose tibiA It is in this range that theV major part of the ca rbo-r'iiii-L tion takes place. It is extremely important' that the rate of temperature rise throngh this temperature range be controlled so that the weight yield of c'arbo 1 `1` fiber will be greater, preferably, than 45 percent' o\f the c bon content of the original raw regenerated cellulose, and so that the tensile strength ofthe resultant'carboniibei" will be at least 5,000 p. s.i. The temperature rise through thi-s range for a single fiber, for example, should take place uniformly in not less. than Srininuts and preferably over a period of one hour so as to preventexcessively fast gasification, s uch as would otherwisedamag'e the fiber. In actual practice, utilizinga mass .of fibersthe time required to raise the temperature o f 4the entire nia'ss of fibers through this range will exceed the timerequired for an individual fiber according .tothe heat, tran sfe r c har acteristics of the particular, equipment employed and the volume ofthe mass offibfers-v The gaseous decomposition products givemoffdu the heating, operation can themselvesprovide the inert, oxygen-free atmosphere if properly contained In` ,order; to avoid brittl eness in the product, theffiberddiameteri of the raw materials s'hould be'` less than abou;t 2 0 O microns. Preferably, the'ber diameter is lessl than 100 rnicrons.

The raw materials may, be` tijeateddnthefqrm offlco'n tinuous mono-filamentain ghyforrr'rv of shortflerigth .or staple fibers, the f orin oflyarn" of, woven webs; or. any other suitable fiber for '1r`1. Continuous mo'no-fila-, ments or yarns are preferredfsince they can be ,contin ously treatedj by passag e through a suitable furnace or other heating apparatn's. ,V ,i i

'l`l 1econtiui.i`o`usprocess` may `b 4 furnace having a p reheat sect1onf..fol lowed..b -pheric trap, .acarboniziing section aridaicool through, which the fiber, is drawn.,4` 'lghe roller .for the fiber shoulclfbe'ofi ceramic material, `an i aterial is preferably. suppo rit-edA andwguid A furnace onk a guide belt or beltsoi g1 1 a rtz.glassclcjthn Inasmuchas the fibers undergo. shrinkageofffrorn to 35% during carbonization, provision must, be, made for such shrinkage by providing for multiple-driver gf. quartzbelts in the carbonizatipn zjone f l`he cog l ing. s ec tioni may comprise water j acketedheat transfergplates,

The process may alsobe `carried out batchwiseyiu-. suitable furnace provided With adequate temperature controlrneans. ,y ff( Produtsrrodud by the abqvezdesribedthernial der composition processhave a .wide,se9pe ;of industria1 u s es., Thavbon .fibers are strong, yethighly iexible and man be readily fabricated into the desired form or assembled with other components foruse f-huS, Coritinuous carbon filaments may be.wover1 into ,yarn and/or clothgfor then, malinsulation, filtration applications nad., the .like..:i.Th.e. yarn, cloth, or staple carbon fiberstghaving sufficient strength to provide a sc lfzsupporting mass of fibers, may be formed into mats or padsforsimilar uses. Also, the carbon fibers in yarn, or staple form mayabemsedfas a catalyst 0r` Catalyst Carrier, and;L as a eaulkng mateal for; specialized applications. Other industrial` applications will readily present themselves to those skilled in the art.

If desired, the brous raw material may be formed before carbonization into mats, pads, orY continuous webs of low bulk density and having a high degree of shape retention by bonding the bers together with a suitable thermosetting resin such `as urea formaldehyde. The resin should be applied at a low viscosity such that cross-ber cementing occurs without the deposition of excessive or thick resin masses.v Any extensive thickening ofthe ber diameters or the formation of nodules of resin on the bers `is undesirable and produces brittle Vsections in the nished product. Preferably,the resin bond lm is of the sameorder ofmagnitude as the ber diameter. The cured,resinbonded ber mats or pads are carbonized in accordancewithV the above-described process to produce carbon-bonded, carbon ber mats or pads suitable forense in air lters, as thermal insulation and the like. e

V' It isjwithin the scopeofqthis invention to provide the carbon` bersV withV coatings of various types, applied either before or after carbonization. Such coatings may include oxides for various purposes,'i.e., MgO, ZnOg, etcQ, forimp'roved reproong, to minimize-the need to protect the material from-oxidizing atmospheres when used as la thermal insulation; Fe203, Cr2O3, A1203, as catalyst surfaces for catalytic reactions utilizing `the carbon ber as the carrier; CuO, CuzO, etc., for inversion of the selective adsorption characteristics to provide specic adsorption properties; andappropriate oxides to change the black color ofthe carbon bers.

The above and other surface coating materials may be introducedprior to or during regeneration and ber formation. This simplies the coating process and produces more thorough and-uniform coatings, more imperto the ber. It has been found that during the'carbonization process the raw material undergoes a change'from an elecnace on ceramic blocks 12 was a set of three rectangular iron pans 14, 15 and 16 of progressively increasing size.V The pan 14 measured 19" in length, 10 in width and 6 in depth; the pan 15 measured 20 X 11" x 61/2; and

can Viscose Co., 5.5 denier; length, 5"-7; qual., A;

type, var. reg.; lustre, brt.; sym., 1432) to prevent pack-` ing.V Pan 14 wasthen. covered with pan 15 and the two pans inverted and then covered with pan'16. 'Ihe furv Vnace was preheated to 300 F. for about l5 minutes and vious coatings, and coatings with a greater degree of bond the assembly of the three pans put into the center of the furnace on ceramic blocking to permit uniform movement of air. The furnaceand contents were then heated slowly through the gasication stage (300-500 F.) for 21A hours. The temperature was then allowed to rise to 1000 F. to drive o Vthe gases, the lfurnace then turned olf and the batch allowed to cool for 18% hours. v

The carbon bers producedV had a `tensile strength of l 10,000 p.s.i. and a weight yieldkof 52% of the carbon content of the raw regenerated cellulose bers. Y

The followingrexample vdescribes the production of activated kcarbon wool bers by the batch method:

f I ExampleVV vThe apparatus described in ,Example 1 was utilized with l the addition of a lengthY of 1i-inch steel tubing 30 welded through oneendV of thepan 15 andV to the bottom, the tubing being provided With a plurality (-about 6 in this case) of l 1zfinch holes 31 equally spaced inside the pan length. The tubing passed through the furnace'port- 11.`

uctrnay be made to exhibit variable specic resistance.

, SuehV materials are useful in electronic applications suchV asin making sensing elements, transducers, conductivity devices, andthe like.`

Carbon bers produced by the present carbonization method have verylow adsorption'capacity. These same bers jmay, however, befactivatedV to provide saturation adsorption capacities fori carbon tetrachloride, for exam! ple, of E10-50% by Weight of the activated carbon ber, whilestill retaining a higrhproportionjof the strength properties ofthe unactivated carbonized ber. It has Y been found that the vunactivated carbonized bers may be activated Vbyjreattion with steam at temperatures from Y 1Z00 to 1800 F. ThisV is( the well knownactivation process whichhas heretofore, been, applied to vgranular carbon materials'. 'Y The activation process may be carried out continuouslyon continuous laments by introducing a steam ret action? chamber immediately prior `to 'the cooling ,sectionV Y' carried out oni a small-scale batch operation, but itis to be understood that'theinvention-is not to be liimted to the details set forth: e

-Examplel j The apparatus is shown diagrammatically inthe drawingand includes a 4 bur`ner, gas-redbox kiln furnace 10 provided with a side port 11. Mounted inside the fur- A S-gallon bottle 39 of distilled water was positioned on top of the furnace'andprovided with a supply tube 40 conl nected to the tubing 50.V A stop-cock 45 was also provided in the tube 40.

The carbonization step vof this examplewas identical to that of Example 1, except that here, following the 2%- hour carbonization step, the temperature of the carbon bers was raised to 1450" F., and maintained there for about'2 hours, during which time about 5 gallons of distilled Water from the bottle 39 wasV- slowly fed by gravityk into the tubing 30. Steam was thus -forced out of the holes- 31 and through the carbonized bers to activate the same. Atgthe end ofthe two-hour period, Vthe batch was dried by lowering the temperature to about 500 F. for about l5V j minutes. The furnace was then allowed to cool for about 18% hours as in Example 1. The activated carbon bers yF. for 21/2 hours. The temperaturen/as then raised` to l l000 F. to drive oi gases from the furnace; The batch of ycarbonized bers was Vthen permitted to cool to room temperatures over a period of approximately 18 hours.

VThe carbon bers thus 'produced were tested and revealed a tensile strength of 8,000p.'s.i. and a Weight yield equal to 50.4% of the carbon content of the raw cupram? monium rayon bers. p

' Example 4 e Again, utilizing the apparatus described in connection with Example 1, a 1.5 pound batch of 1 denier saponied acetate rayon bers was carbonized yby slowly heating the same through a temperature range of 250". F. to 500 F.

for 21/2 hours. The temperature was then raised to 1000 F. and the batch allowed to cool to room temperature over an 18 hour period. The resultant carbonized bers were tested and revealed a tensile strength of 11,200 p.s.i. and a weight yield equal to 51.7% of the carbon content of the original saponied acetate rayon bers.

Further tests and experiments in connection with single bers or mono-laments of these materials reveal that the rate of increase in temperature through the critical range of -from about 250 F. to about 500 F. should be accurately controlled, so that the increase in temperature from 250I F. to 500 F. will consume a period of time of at least 8 minutes. If the temperature rise is attained in a time shorter than 8 minutes, the tensile strength and weight yield of the resultant carbonized ber will be materially reduced.

Having fully described my invention, `it is to be understood that I do not wish to be limited to the details set forth, but my invention is of the full scope of the appended claims.

Having thus described my invention, what I claim is:

l. A process for the production of a carbon ber comprising the steps of heating viscose rayon ber in an inert atmosphere through a temperature range of from about 300 F. to about 500 F., said heating requiring at least 30 minutes to attain said 500 F. temperature.

`2. A process for the production of a carbon ber comprising the steps of heating viscose rayon ber in an inert atmosphere through a temperature range of from about 300 F. to about 500 F., said heating requiring about two hours to attain said 500 F. temperature.

3. A process for the production of a carbon ber comprising the steps of heating viscose rayon ber in an inert atmosphere through a temperature range of from about 300 F. vto about 500 F., said heating requiring at least 30 minutes to attain said 500 F. temperature, and subjecting the ber thus produced to the action of steam at an elevated temperature to activa-te the same.

4. A process `for the production of a carbon ber comprising the steps of heating viscose rayon ber in an inert atmosphere through a temperature range of from about 300 F. to about 500 F., said heating requiring about two hours to attain said 500 F. temperature, and subjecting the ber thus produced to the action of steam at an elevated temperature to activate the same.

5. The method of making a carbon ber which cornprises heating a non-thermoplastic, regenerated cellulose ber in an inert atmosphere through a temperature range of `from approximately 250 F. to approximately 500 F., said heating requiring at least 8 minutes to attain said 500 F. temperature.

6. The method of making a carbon ber which comprises heating a non-thermoplastic, regenerated cellulose ber in an inert atmosphere through a temperature range of from approximately 250 F. to approximately 500 F. in a time period of not less than 8 minutes; and subjecting the ber thus produced to the action of steam at an elevated temperature to activate the same.

7. The method of making a carbon ber having a tensile strength of at least 5,000 p.s.i. which comprises heating in an inert atmosphere a regenerated cellulose ber selected from the class consisting of viscose rayon, cuprammonium rayon and saponied acetate rayon, through a temperature range of from about 250 F. to about 500 F., the increase n temperature yfrom about 250 F. to about 500 F. being accomplished in not less than 8 minutes.

8. 'I'he method dened in claim 7 including the further step of subjecting the thus heat-treated ber to the action of steam at a further elevated temperature to activate the same.

References Cited in the le of this patent UNITED STATES PATENTS 2,925,879 Costa et al Feb. 23, 1960 FOREIGN PATENTS 11,997 Great Britain 1886

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2925879 *Nov 6, 1944Feb 23, 1960Costa Joseph LFilter medium
GB188611997A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3179605 *Oct 12, 1962Apr 20, 1965Haveg Industries IncManufacture of carbon cloth
US3256206 *Dec 3, 1964Jun 14, 1966Union Carbide CorpActivation of textile forms of carbon
US3265557 *Jan 9, 1964Aug 9, 1966Atlantic Res CorpFibrous compositions
US3294489 *Dec 19, 1961Dec 27, 1966HitcoProcess for preparing carbon fibers
US3295559 *Sep 17, 1962Jan 3, 1967Union Carbide CorpInduction heating susceptor and method for producing same
US3301742 *Jun 23, 1961Jan 31, 1967Haveg Industries IncLaminate comprising carbon fibers, carburized resin, and inorganic oxide fibers
US3305315 *Sep 20, 1962Feb 21, 1967Union Carbide CorpProcess for manufacturing flexible carbonaceous textile material
US3322489 *Jul 28, 1964May 30, 1967Lorraine CarboneProcess of graphitizing "polynosic" regenerated cellulose fibrous textile and resulting fibrous graphite textile
US3333926 *Oct 30, 1963Aug 1, 1967Union Carbide CorpProcess for carbonizing cellulosic textile materials
US3337301 *Jan 17, 1964Aug 22, 1967Havey Ind IncProcess for carbonizing fibrous cellulosic materials
US3356525 *Nov 18, 1963Dec 5, 1967Hitco CorpMetal carbide formation on carbon fibers
US3367812 *Nov 14, 1962Feb 6, 1968Union Carbide CorpProcess of producing carbonized articles
US3395970 *Oct 30, 1963Aug 6, 1968Deering Milliken Res CorpMethod of carbonizing polyacrylonitrile impregnated cellulose, cyanoethylated cellulose and acrylonitrile graft copolymerized cellulose textiles
US3407038 *Jul 9, 1962Oct 22, 1968Union Carbide CorpShredded carbonaceous fiber compactions and method of making the same
US3461082 *Oct 4, 1965Aug 12, 1969Nippon Kayaku KkMethod for producing carbonized lignin fiber
US3476703 *Feb 16, 1968Nov 4, 1969Nat Res DevTreatment of carbon fibres and composite materials including such fibres
US3484183 *Jun 4, 1965Dec 16, 1969Minnesota Mining & MfgHeat-resistant black fibers and fabrics derived from rayon
US3533741 *May 17, 1968Oct 13, 1970Courtaulds LtdProcess for the production of filamentary carbon
US3886093 *Dec 14, 1973May 27, 1975Westvaco CorpActivated carbon with active metal sites and process for producing same
US3917776 *Sep 27, 1973Nov 4, 1975Mitsubishi Rayon CoProcess for producing carbon fiber
US3997638 *Sep 18, 1974Dec 14, 1976Celanese CorporationProduction of metal ion containing carbon fibers useful in electron shielding applications
US4045368 *Oct 25, 1974Aug 30, 1977Kureha Kagaku Kogyo Kabushiki KaishaProcess for production of activated carbon spheres
US4181513 *Apr 26, 1977Jan 1, 1980Toyobo Co., Ltd.Carbon adsorptive filter material with layers of reinforcing non woven fabrics needle punched
US4186101 *Jan 13, 1978Jan 29, 1980Schumacher'sche Fabrik Gmbh & Co. KgFilter
US4234326 *Jul 26, 1978Nov 18, 1980The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern IrelandFilter assemblies with layers of activated carbon fibrous cloth
US4248736 *Jan 2, 1979Feb 3, 1981Kuraray Co., Ltd.Fibrous adsorbent for hemoperfusion
US6051096 *Jul 11, 1996Apr 18, 2000Nagle; Dennis C.Carbonized wood and materials formed therefrom
US6124028 *Dec 23, 1998Sep 26, 2000Nagle; Dennis C.Carbonized wood and materials formed therefrom
US6670039Apr 6, 2000Dec 30, 2003Dennis C. NagleCarbonized wood and materials formed therefrom
US6696387Jun 2, 1995Feb 24, 2004Hyperion Catalysis International, Inc.Catalysts for the manufacture of carbon fibrils and methods of use thereof
US6699454Jun 7, 1995Mar 2, 2004Hyperion Catalysis International, Inc.Catalysts for the manufacture of carbon fibrils and methods of use thereof
US6967014 *Dec 5, 2000Nov 22, 2005Snecma MoteursMethod of obtaining a carbon fiber fabric by continuously carbonizing a cellulose fiber fabric
US7914683 *Dec 4, 2009Mar 29, 2011University Of Central Florida Research Foundation, Inc.Particles of spilled oil-absorbing carbon in contact with water
US8544207Mar 13, 2009Oct 1, 2013Euteq LlcHydroponic plant growth systems with activated carbon and/or carbonized fiber substrates
US9096955Sep 27, 2012Aug 4, 2015Ut-Battelle, LlcMethod for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby
US9096959Feb 22, 2012Aug 4, 2015Ut-Battelle, LlcMethod for production of carbon nanofiber mat or carbon paper
US9631298 *May 16, 2012Apr 25, 2017Stora Enso OyjMethod for the production of lignin-containing precursor fibres and also carbon fibres
US20040005461 *Apr 23, 2003Jan 8, 2004Nagle Dennis C.Carbonized wood-based materials
US20110120005 *Mar 13, 2009May 26, 2011Sustainable Strategies LlcHydroponic plant growth systems with activated carbon and/or carbonized fiber substrates
US20140194603 *May 16, 2012Jul 10, 2014Stora Enso OyjMethod for the production of lignin-containing precursor fibres and also carbon fibres
EP1176234A2 *May 12, 1993Jan 30, 2002Hyperion Catalysis International, Inc.Catalyst supports, supported catalysts, methods of making the same and methods of using the same
EP1176234A3 *May 12, 1993Nov 6, 2002Hyperion Catalysis International, Inc.Catalyst supports, supported catalysts, methods of making the same and methods of using the same
WO1993024214A1 *May 12, 1993Dec 9, 1993Hyperion Catalysis International, Inc.Catalyst supports, supported catalysts methods of making the same and methods of using the same
Classifications
U.S. Classification502/420, 55/528, 264/DIG.190, 210/509, 423/447.8, 423/447.9, 55/DIG.450
International ClassificationB01J27/22, C01B31/08, B01J21/18, D01F9/16, D01F11/12
Cooperative ClassificationB01J21/18, Y10S55/45, B01J27/22, D01F11/12, Y10S264/19, D01F9/16, C01B31/08
European ClassificationB01J27/22, B01J21/18, C01B31/08, D01F9/16, D01F11/12