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Publication numberUS3285696 A
Publication typeGrant
Publication dateNov 15, 1966
Filing dateApr 5, 1963
Priority dateAug 25, 1960
Publication numberUS 3285696 A, US 3285696A, US-A-3285696, US3285696 A, US3285696A
InventorsTsunoda Yasugoro
Original AssigneeTokai Denkyoku Seizo Kabushiki
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method for the preparation of flexible carbon fibre
US 3285696 A
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Description  (OCR text may contain errors)

United States Patent '0.

3,285,696 METHOD FOR THE PREPARATION OF FLEXIBLE CARBON FIBRE Yasugoro Tsunoda, Kumamoto-ken, Japan, assignor to Tokai Denkyoku Seizo Kabushiki Kaisha, Tokyo, Japan No Drawing. Filed Apr. 5, 1963,'Ser. N0.270,807 Claims priority, application Japan, Aug. 25,1960, 35/ 36,145 3 Claims. (Cl. 23-209.1)

This application is a continuation-in-part of my earlier previously copending application, Ser. No. 97,461 filed March 22, 1961, now abandoned.

This invention relates to methods for the preparation of flexible heat resisting and corrosion resistant fibre.

The corrosion resistance of carbon and graphite against various chemicals and the heat resistance of carbon and graphite are substantially perfect excepting when these materials are placed in an oxidizing atmosphere. It has therefore been considered desirable to produce woven fabric made of carbon or graphite but which also has satisfactory mechanical strength It is known that if a fibre (for example, cotton or Orlon) containing carbon is heated at high temperatures (700-3,000 C.) in an inert gas atmosphere such as nitrogen or argon, the fibre retains the shape it had before-the heat treatment. Fibre obtained in this way is, however, so brittle that yarn and woven fabric made of such fibre are of no practical use.

It is an object of this invention to prepare fibrous carbon and graphite having improved properties.

Other objects and advantages of this invention will be apparent from the following description of some preferred embodiments.

The invention provides a method for the preparation of heat resisting and corrosion resistant fibre, characterized in that fibre, made of a material selected from the group consisting of acrylonitrile polymer and acrylonitrile copolymer prepared from less than 85 mol percent of acrylonitrile and not more than 15 mol percent of a monovinyl compound, is heated at a temperature from 180 to 550 C. in an oxygen-containing atmos phere for a time sufficient to blacken the fibre. Then the blackened material is carbonized and if necessary graphitized by a conventional method.

The fibrous carbon and graphite prepared by the methd mentioned. above are mechanically stronger and more flexible than those made by direct carbonization or graphitization without the pretreatment according to the invention.

According to the invention, a product such as -a filament, staple, or batting is made of the fibre which is made from acrylonitrile homopolymer or copolymer produced by copolymerizing not less than 85 mol percent of acrylonitrile with not more than 15 mol percent of a monovinyl compound such as methyl acrylate, methyl methacrylate, vinyl, acetate, vinyl chloride, vinylidine chloride, 2-methyl-5-vinyl pyridine or the like. This product is heated for 5-60 minutes at 180-230 C. in an oxygen containing atmosphere such as air. The temperature and time necessary for heating depend on the thickness of the fibre or woven fabric but, for convenience, it is determined by the degree of blackening of the fibre. Polyacrylonitrile becomes yellowish, brown and black successively by heating in air, but yellowish and brown fibres are not suit-able for the purpose of this invention since their carbonized or graphitized products are brittle.

Then the blackened. fibre is carbonized at a temperature between 700-1200 C. for not less than 1 hour in an inert atmosphere to form a carbonized fibre. If a more heat resistant and corrosion resistant fibre is required, the carbonized fibre is graphitized at a temperature bep .JCC

tween 1200-3000 C. in an inert atmosphere to form a graphitized fibre. Said inert atmosphere may be an inert gas or a packing material such as graphite, carbon black and silica. 1

Example I 'Staple of acrylonitrile copolymer containing 4 mol percent of methyl acrylate (yarn countings #48, two-ply) was heated in air at 220 C. for 3 hrs. in order to blacken it completely. Then the blackened fibre was heated in a nitrogen atmosphere at 1,000 C. for 1 hr. The product was not broken by bending, its tensile strength being above 60 g./yarn. The same staple was heated in air at 220 C. for 20 minutes and. a dark brown fibre was obtained. Then the fibre was heated in a nitrogen atmosphere at 1,000 C. for 1 hour. A carbonized fibre resulted which was so brittle that it was easily broken by bending and its tensile strength was 20 g./yarn. On the other hand, the tensile strength of the product which was made merely by direct heating of the same fibre of polyacrylonitrile in a nitrogen atmosphere at 1,000 C. for 1 hr. was as small as about 6-11 g./yarn. The latter product was relatively'inflexible so that it too was readily broken by bending.

Example 2 Batting of acrylonitrile polymer mol percent) was blackened by heating in air at 230 C. for 15 minutes. The blackened cotton obtained in this way was then heated in a nitrogen atmosphere at 1,000 C. for 1 hr. The product retained its original form and was flexible. On the other hand, the product which was made merely by heating the same batting in a nitrogen atmosphere at 1,000 C. for 1 hr. formed a conglomerate which was easily broken by a small force.

Example 3 A fibre made of copolymer of acrylonitrile 92 mol percent and 2-methyl-5-vinylpyridine 8 mol percent was treated in the manner mentioned in Examples 1 and 2. Substantially the same results were obtained.

Example 4 Woven fabric (plain weave; warp and woof yarn countings No. 48, two-ply) made of yarns of acrylonitrile copolymer containing 4 mol percent of methyl acrylate was heated in air at 220 C. for 1 hr. and then the blackened fibre was heated in nitrogen at 1,000 C. for 1 hr. The product was flexible and not broken even by bending to an angle of 180 degrees. The woven fabric heated solely at 1,000 C. for 1 hr. was broken by bending to angle of 15.

Example 5 The same yarn as that used in Example 1 was blackened by being heated in air at 220 C. for 30 minutes. Then it was buried in graphic powder and graphitized at 3,000 C. The product was flexible, its tensile strength being above 40 g./yarn. The same yarn was buried in graphite and graphitized at 3,000 C. The product obtained in this way was very brittle, its tensile strength being below 6 g./yarn.

What is claimed is:

1. A method for the preparation of flexible heat resistant and corrosion resistant fibre, comprising pretreating a fibre, which is to be carbonized and which is selected from the group consisting of acrylonitrile homopolymer and acrylonitrile copolymer prepared from not less than 85 mol percent of acrylonitrile and not more than 15 mol percent of a monovinyl compound, by heating the fibre at a temperature of from 180 to 550 C. in an oxygen containing atmosphere for a time sufficient to blacken the fibre',and then carbonizing the blackened fibre at a temperature between 700 and 1200 C. for not less than one hour in an inert atmosphere to form a carbonized fibre. Y

2. A method according to claim 1 wherein said carbonized fibre is then graphitized at a temperature between 1200 to 3000 C. in an inert atmosphere to form a graphitized fibre.

3. A method as claimed in claim 1, wherein the pretreatment heating is effected for 5-60 minutes..

7 4' References Cited by the Examiner UNiTED "STATES PATENTS 2,799,915 7/1957 Barnett et al. 8-115.5 X 3,011,981 12/1961 Soltes 252S02 3,027,222 3/ 1962 Wilkinson 8115.5 3,107,152, 10/1963 Ford et al. 23209'.2 X

-, MILTON WEISSMAN, Primary Examiner.

OSCAR R. VERTIZ, Examiner.

E. J. MEROS, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2799915 *Mar 30, 1953Jul 23, 1957Johns ManvilleThermal modification of acrylonitrile polymers
US3011981 *Apr 21, 1958Dec 5, 1961Soltes William TimotElectrically conducting fibrous carbon
US3027222 *Sep 3, 1957Mar 27, 1962Du PontFireproof acrylonitrile copolymers
US3107152 *Sep 12, 1960Oct 15, 1963Union Carbide CorpFibrous graphite
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3412062 *Apr 19, 1965Nov 19, 1968Nat Res DevProduction of carbon fibres and compositions containing said fibres
US3443899 *Jul 22, 1966May 13, 1969North American RockwellProcess for making graphitic-type fibers
US3449077 *Feb 13, 1967Jun 10, 1969Celanese CorpDirect production of graphite fibers
US3454362 *Aug 26, 1965Jul 8, 1969Union Carbide CorpProcess for producing fibrous graphite
US3488151 *Sep 1, 1967Jan 6, 1970Union Carbide CorpPreparation of carbon fibers from polyvinyl alcohol base fibers
US3497318 *Sep 1, 1967Feb 24, 1970Union Carbide CorpPreparation of carbon textiles from polyacrylonitrile base textiles
US3503708 *Dec 27, 1968Mar 31, 1970Union Carbide CorpGraphite yarn
US3508871 *May 29, 1963Apr 28, 1970Carborundum CoCarbonizing fibrous materials
US3508874 *Jan 12, 1968Apr 28, 1970Celanese CorpProduction of carbon yarns
US3528774 *Mar 14, 1967Sep 15, 1970Us Air ForceFormation of high modulus,high strength graphite yarns
US3529934 *Jan 4, 1968Sep 22, 1970Nippon Carbon Co LtdProcess for the preparation of carbon fibers
US3532466 *Nov 14, 1966Oct 6, 1970Nat Res DevProduction of carbon fibres
US3533741 *May 17, 1968Oct 13, 1970Courtaulds LtdProcess for the production of filamentary carbon
US3533743 *May 28, 1968Oct 13, 1970Great Lakes Carbon CorpProcess for the manufacture of continuous high modulus carbon yarns and monofilaments
US3539295 *Aug 5, 1968Nov 10, 1970Celanese CorpThermal stabilization and carbonization of acrylic fibrous materials
US3541582 *Jul 5, 1967Nov 17, 1970Nat Res DevManufacture of carbon cloth from polymeric fibre material
US3547584 *Dec 18, 1967Dec 15, 1970Celanese CorpGraphitization of fibrous polyamide resinous materials
US3607059 *Apr 2, 1969Sep 21, 1971Great Lakes Carbon CorpProcess for the manufacture of filamentary carbon products
US3615212 *Mar 5, 1969Oct 26, 1971Rolls RoyceMethod of manufacturing carbon fibers
US3619139 *Jan 31, 1969Nov 9, 1971Morganite Research & Dev LtdManufacture of carbon filaments
US3635675 *May 28, 1968Jan 18, 1972Us Air ForcePreparation of graphite yarns
US3648452 *Jul 28, 1969Mar 14, 1972Dunlop Holdings LtdMethod of forming reinforcing yarns or cords
US3650668 *Mar 9, 1970Mar 21, 1972Celanese CorpThermally stabilized acrylic fibers produced by sulfation and heating in an oxygen-containing atmosphere
US3656903 *Apr 10, 1969Apr 18, 1972Celanese CorpDirect production of graphite fibrous materials from preoxidized acrylic fibrous materials
US3660018 *Jul 31, 1970May 2, 1972Rolls RoyceMethod of manufacturing carbon fibre
US3663170 *Jan 31, 1969May 16, 1972Morganite Research & Dev LtdManufacture of carbon filaments
US3699210 *Sep 6, 1968Oct 17, 1972Monsanto Res CorpMethod of graphitizing fibers
US3716332 *Jul 27, 1970Feb 13, 1973Ducommun IncCarbonization of wool
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US3914394 *Jan 31, 1974Oct 21, 1975Japan Exlan Co LtdProcess for producing carbon fibers
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US4237108 *Oct 9, 1979Dec 2, 1980Toray Industries, Inc.Process for producing carbon fabric
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US4856179 *Jan 5, 1988Aug 15, 1989Hoechst Celanese Corp.Method of making an electrical device made of partially pyrolyzed polymer
US7534854Jan 31, 2006May 19, 2009Ut-Battelle, LlcTreatment chamber adapted to maintain atmosphere and plasma-derived gas containing reactive oxidative species; polyacrylonitrile fibers for carbonization treatments
US7649078Mar 28, 2006Jan 19, 2010Ut-Battelle, LlcApparatus and method for stabilization or oxidation of polymeric materials
US7786253May 14, 2009Aug 31, 2010Ut-Battelle, LlcOxygen plasma generator with a microwave power source connected to a vacuum system having a pump by the treatment chamber; polymer delivery system having a feed reel at the inlet of the treatment chamber and a take up reel at the exit; useful for preparing polyacrylonitrile fibers for carbonization
US20110114342 *Sep 13, 2010May 19, 2011Kazuhiro OnoFire barrier protection for airplanes comprising graphite films
EP0278139A1 *Feb 12, 1987Aug 17, 1988Zoltek CorporationManufacture of controlled surface resistance carbon fibre sheet products
Classifications
U.S. Classification423/447.6, 8/115.51, 264/DIG.190, 8/115.54
International ClassificationD06M11/34, D01F9/22
Cooperative ClassificationD01F9/225, D01F9/22, Y10S264/19, D06M11/34
European ClassificationD01F9/22B, D06M11/34, D01F9/22