US3663173A - Process for producing carbonized fibrous products - Google Patents

Process for producing carbonized fibrous products Download PDF

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Publication number
US3663173A
US3663173A US733516A US3663173DA US3663173A US 3663173 A US3663173 A US 3663173A US 733516 A US733516 A US 733516A US 3663173D A US3663173D A US 3663173DA US 3663173 A US3663173 A US 3663173A
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carbonized
percent
tension
yarn
heating
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Stanley E Ross
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JP Stevens and Co Inc
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JP Stevens and Co Inc
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Assigned to BANKERS TRUST COMPANY, A NY BANKING CORP. reassignment BANKERS TRUST COMPANY, A NY BANKING CORP. SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: J.P. STEVENS & CO.
Assigned to J.P. STEVENS & CO., INC. reassignment J.P. STEVENS & CO., INC. RELEASE SECURITY INTEREST & ASSIGNMENT. Assignors: BANKERS TRUST COMPANY
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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
    • D01F9/16—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from products of vegetable origin or derivatives thereof, e.g. from cellulose acetate

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  • this invention relates to a carbonization process whereby tension is applied to partially carbonized cel lulosic textile substrates during heat treatment to produce strengthened more fully carbonized products.
  • tension as used throughout this application is a generic term including all means of applying stress to a cellulosic substrate. This term includes stretching, using draw rolls operating at different rates of speed, the application of weights, the use of gears and the like.
  • carbonization refers to a process whereby substrates containing less than 45 percent carbon are thermally transformed to carbonized products containing from 50-100 percent by weight carbon.
  • partially carbonized refers to cellulosic substrates such as yarns, fibers, filaments, cloths and the like whose carbon content varies between about 50 percent up to about 85 percent by weight carbon.
  • the more fully carbonized products are those in which the carbon content varies between about 85-100 percent by weight carbon.
  • FIGS. 1, 2 and 3 represent flow sheets relating to different embodiments of the inventive process described in detail in the specification below.
  • Carbonized structures are advantageous compared to graphitized structures in that they are less costly, are less dense, have higher surface areas and are better electrical and thermal insulators. Because of their lower thermal conductivity the carbonized structures also have superior cold side shielding properties. Partially graphitized structures suffer from the same disadvantages only to a lesser degree.
  • More specific objects are the production of carbon products having many of the desirable attributes of graphite without some of the undesirable characteristics of graphite; said products being produced by a less costly process conducted at substantially lower temperatures than are required for graphitization and without the more specialized equipment required for graphitization.
  • the above objects are achieved by applying tension to a cellulosic substrate while it is exposed to carbonizing temperatures until a carbonized product containing between about 60-100 percent by weight carbon is obtained.
  • a cellulosic substrate is heated between about 200 to 300 C. to produce a carbonized intermediate having a carbon content of from about 50 to 60 percent by weight carbon.
  • the carbonized intermediate is exposed to temperatures ranging from about 500 to l,000 C., while a first tension is applied to the heated material. The heating is continued until a carbon content of from about 70-85 percent by weight carbon is obtained.
  • the above material is heated between about l,000 to 1,500" C. for a time sufficient to produce a product having up to percent by weight carbon, substantially free from graphite as demonstrated by X-ray diffraction patterns.
  • a rayon yarn substrate is treated with one or more of the compositions described infra and designated as catalyst, in l-l0 percent by weight concentration until a pickup of -300 percent by weight on the substrate is achieved.
  • the treated yarn is dried to a moisture content of approximately 8-12 percent and is first heated at 200-300 C. During this heating no tension is applied to the yarn and the yarn is allowed to shrink freely.
  • This lack of tensioning during the initial carbonization is necessary because the cellulosic substrates unlike other carbon-containing substrates such as polyacrylonitrile, are greatly weakened during this heating stage due to the complex molecular changes which have taken place. Therefore, it should be emphasized that the tensioning cannot be performed during the initial carbonization between 200 and 300 C. and is confined to the subsequent carbonization of the 50 percent by weight carbon yarn materials produced from the initial carbonization.
  • the product obtained is a fibrous material having a carbon content between about 50-60 percent by weight carbon.
  • the first carbonized yarn product is then heated a second time between about 500 C. to about l,000 C. in a non-oxidizing atmosphere while a first tension is applied to the yarn.
  • the tension applied is less than the amount required to break the yarn, and the heating is continued until a second carbonized yarn having a carbon content between about 70-85 percent by weight carbon is produced.
  • This carbon yarn can then be wound for future use.
  • this carbon yarn product is heated a third time between about 1,000 to 1,500" C. in a non-oxidizing atmosphere such as nitrogen, helium and argon or their mixtures with or without air, while a second tension is applied to the yarn. Heating is continued until a third carbonized product having a carbon content between about 85-100 percent by weight carbon is produced.
  • the cellulosic substrates of this invention are limited to the cellulosics of natural and synthetic origin.
  • the cellulosics are preferred substrates because of their high carbon content, good initial strength, lower cost and the good quality of the resultant carbonized product.
  • the preferred cellulosic substrates are the regenerated celluloses or rayons but cotton, linen, hemp, jute, flax, sisal and the like can be used of convenient. These substrates are preferably in the form of their yarn but can be in the form of staple, fibers, continuous filament tows, cloths (woven, knitted or felted), non-woven, random layed fibrous or needle-punched batts, felts, fabrics or tissue, laminates and the like.
  • Carbonization Catalysts While the process of this invention does not require them, the use of carbonization catalysts is preferred as they reduce carbonization time and appear to give products possessing optimum physical properties. Any of the carbonization catalysts previously described in the literature can be employed, particularly diammonium hydrogen phosphate, phosphorothioic triamide, N,N' ,N' -trimethylphosphoric triamide, phosphonitrile amide cyclic trimer, phosphoric triamide, diethyl methylphosphoramidate, methylphosphonic diamide, (chloromethyl)phosphonothionic diamide, trimethyl phosphate, triethyl phosphate, diethyl ethylphosphoramidate and diethyl isopropylphosphoramidate, among many others.
  • the carbonization can be conducted stepwise or continuously through the range of 2501,500 C.
  • the temperature employed depends upon the carbon content desired. At the 50-60 percent by weight carbon level, temperatures between about 200300 C. will suffice whereas to obtain products of 85-95 percent by weight carbon, temperatures in excess of 1,000 C. are required. In the latter case the upper temperature must not go above about l,500 C. or unwanted graphitization with its attendant disadvantages takes place.
  • excellent results have been obtained utilizing a three-step heating cycle. In the first step no tension is applied during heating at 200-300 C. A tensioning step takes place when the carbonization takes place between about 500-l, 000 C. At the end of these two heating stages a product having a carbon content between about 70-85 percent by weight carbon is obtained whereas to obtain a product above 85 percent by weight carbon or higher, a final heating about 1,000 C. and up to l,500 C. is required.
  • the carbonization periods are variable and depend upon the carbonization catalysts and carbonization temperatures employed. However, ordinarily within the framework of the three heating steps described above, the initial heating step require a total of under 1 hour, ordinarily under 30 minutes, whereas the heating between 1,000 and 1,500 C. is very brief, usually under a minute or two.
  • the application of tension to a cellulosic substrate which has been previously carbonized to a carbon-containing intermediate having a carbon content of at least 50 percent by weight carbon is the gist of this invention.
  • the tension can be applied in one or more separate operations dependent upon the equipment available and the convenience of the party.
  • the tension need not be applied by one method generally speaking it can be applied by any known means of applying stress to the cellulosic substrate as it undergoes carbonization. These include deadweight techniques (the application of weights to the substrate), the use of draw rolls traveling at different rates of speed and the like.
  • the amount of tension required for producing a noticeable improvement in the strength properties of the carbonized product is a variable dependent upon several factors, and therefore cannot be stated with precision. Primarily, the tension is dependent upon the number of distinct heating stages employed and the temperatures at which these stages operate. Generally, the tension required ranges between the tension required to exceed the natural shrinkage (5-20 percent of original dimensions) that the substrate undergoes during carbonization up to just under the tension required to exert a breaking stress on the substrate. A convenient way of expressing the tension required is by load per denier. Expressed in this manner the minimum tension that can be effectively applied is of the order of about 0.03 gram/denier of substrate whereas the upper limit as measured by breaking stress is ordinarily in the order of about 0.60 gram/denier. When a threestage heating cycle is used to produce'a carbonized yarn,
  • a tension of about 0.04 to 0.30 gram/denier is applied in the second stage at a tension of about 0.05 to 0.40 gram/denier is applied in the third stage.
  • the tensions will ordinarily range between about 50-150 grams per LOGO-1,200 denier of substrate for the second heating stage and between about 50-200 grams per 650-850 denier of substrate for the third heating stage.
  • the carbonized product has a carbon content ranging between about 70-85 percent by weight carbon. This product is then briefly heated carefully up to no higher than 1,500 C. to raise the carbon content to about -95 percent by weight carbon without forming substantial amounts of undesirable graphite.
  • TENSILE STRENGTH A suitable length of the aforedescribed cellulosic yarn which has been carbonized is taken for sampling. Samples of the 50-60 percent by weight, 70-85 percent by weight, and 85-100 percent by weight carbon yarn are used. All samples are conditioned for 16 hours at 65 percent RH. and 21 C. The sample is tested on an lnstron Tensile Tester (manufactured by Instron Engineering Corp.) as follows: Thesamples are positioned so that the span between the jaws of the instrument are 1 inch, and in some instances 5 inches. An appropriate load cell is used. The rate of extension is 10 percent per minute and the chart speed adjusted so that every inch on MODULUS OF ELASTICITY The modulus of elasticity expressed in grams per denier is determined from the slope of the stress-strain curve obtained in the tensile strength determination.
  • FIGS. 1 to 3 in the drawing describe three embodiments of the process of the instant invention.
  • FIG. 1 shows the preferred 2 (two)-tensioning-3(three)- heating stage embodiment of this invention.
  • a cellulosic substrate 1 is treated with catalyst solution C.
  • the substrate travels in a left to right direction at a pre-selected rate of speed as it enters the first furnace 2 maintained between about '200-300 C. where the first carbonization to about 50 to 60 percent by weight carbon content takes place.
  • the partially carbonized yarn leaves the furnace, passes through a pair of nip-rolls 3 over a set of guide means 5, while being exposed to a first tensioning step applied by means of a tension arm 4. After passing over the set of guide means 5 the substrate passes into a second furnace 6 maintained at between about 500 to 1,000 C.
  • This second carbonized product leaves the second furnace, passes through a second set of nip rolls 7 over guide means 9, has a second tension applied to it through a second tension arm 8 and passes over second set of guide means 9 into the third furnace 10 maintained between about 1,000 to I,500 C. to produce a more fully carbonized product having a carbon content of between about 85-100 percent by weight carbon.
  • This product is taken up or otherwise gathered and stored for further treatment or use.
  • FIG. 2 illustrates a l(one)-tensioning-3(three)-heating stage process.
  • the substrate 21 is treated with catalyst solution C and travels from left to right at a preselected rate of speed to enter the first furnace 22 maintained at about 200 to 300 C. until a first carbonized product of about 50-60 percent by weight carbon is produced.
  • the partially carbonized substrate exits and passes between a first pair of nip-rolls 23 and guide means 25 while a first tension is applied to it by means of a tension arm 24. After passing over guide means 25 the substrate enters a second furnace 26 maintained at about 500 to 1,000 C.
  • third furnace 28 maintained between about l,000 and 1,500 C. where the final carbonization to a product of about 85-100 percent by weight carbon content takes place. Again, this product is taken up" or wound up upon an appropriate storage means. Where a partially carbonized product is desired the procedure shown in FIG. 2 is followed except that the third furnace 28 is dispensed with.
  • FIG. 3 shows a variation of the l(one)-tensioning-3(three)- heating step process of FIG. 2.
  • the substrate 3 treated with catalyst solution C travels from left to right at a rate of speed required to give the desired residence time in the furnaces, enters the first furnace 32 maintained at about 200 to 300 C. and exits as a carbonized product having a carbon content between about 50-60 percent by weight carbon.
  • This partially carbonized substrate passes between a first set of niprolls 33 from which it is drawn into the second carbonizing furnace 34, maintained at about 500 to 1,000 C. to produce a second more fully carbonized product having a carbon content of between about 70-85 percent by weight carbon.
  • the second carbonized product passes through a second set of nip- EXAMPLE 2 APPLICATION OF ONE TENSIONING STEP AFTER THE EXPOSURE OF A PARTIALLY CARBONIZED RAYON YARN SUBSTRATE TO A SECOND HEATING ZONE.
  • Norm-All products have at least 90% by weight carbon.
  • EXAMPLE trimethylphosphoric triamide, phosphonitrile amide cyclic trimer, methylphosphonic diamide, APPLICATION OF ONE TENSIONING STEP To A (chloromethyl )phosphonothionic diamide, trimethyl PARTIALLY CARBONIZED RAYON YARN EXPOSED phosphate, methyl phosphate diethyl To THREE HEATXNG ZONES 5 methylphosphoramidate, diethyl ethylphosphoramidate, In this example the same substrate and catalyst used in exdiethyl isopropylphosphoramidate and diammonium ample l are employed. Experimental conditions are shown in h h Th properties f h fi l products are comParathe a l below! ble to those obtained in example 7.
  • EXAMPLE 6 2o EXAMPLE 9 APPLICATION OF ONE TENSIONING STEP TO A PARTIALLY CARBONIZED RAYON YARN EXPOSED TO TWO HEATING ZONES
  • the substrate of example l is used.
  • Samples 25 a) to (c) have phosphoric triamide catalyst applied to them, while samples (d) to (f) utilize phosphonitrile amide cyclic trimer.
  • diethyl isopropylphosphoramidate and diammonium Samples (a) to (c) utilize phosphoric triamide as catalyst. 50 hydrogen phosphate. Again comparable products are ob- Samples ((1) and (e) utilize phosphononitrile amide cyclic tained.
  • EXAMPLE 8 THE USE OF DIFFERENT CARBONIZATION CATALYSTS IN THE ONE-TENSIONING TWO-HEATING ZONE PROCESS OF EXAMPLE 7
  • EXAMPLE I0 70 APPLYING THE PROCESS DISCLOSED IN BELGIAN PAT. NO. 700,755 TO APPLICANTS CELLULOSIC SUBSTRATE Belgian PAT. No. 700,655 discloses that strengthened carbonized fibers can be obtained by applying tension to a polyacrylonitrile fiber substrate during its initial carbonization at temperatures ranging from about 220 to 250 C. The carbonization is carried out in an oxidizing atmosphere. In order to determine whether the process of the Belgium patent which is performed on a non-cellulosic substrate (polyacrylonitrile),
  • the rayon yarn substrate of example 1 is exposed to an oxidizing atmosphere at a temperature of 240 C. during carbonization. During this time, as specified by the Belgian Patent, sufficient tension is applied to the yarn to prevent it from shrinking. After a short period of time the yarn ruptures causing the experiment to be terminated. Upon repeating the experiment the same yarn failure is encountered during approximately the same reaction time.
  • the carbonized yarn products of this invention have greatly improved tensile strength and modulus of elasticity compared to carbonized yarns of the prior art. Further, the gain in strength and modulus properties is achieved without the substantial presence of graphite. As has been disclosed earlier for certain end uses, carbonized products are advantageous to the corresponding graphitized structures.
  • a process as claimed in claim 1 including the additional step of heating said second carbonized product at a temperature of from about 1,000 to l,500 C. in a non-oxidizing atmosphere while applying tension thereto until a third carbonized product is obtained having a carbon content of from about 85 to percent by weight, said tension ranging from that required to exceed the shrinkage forces in the second carbonized product during heating, up to but less than the tension required to exert a breaking stress on the second carbonized product during heating.
  • a process for preparing a carbonized textile product comprising:
  • a process for preparing a carbonized yarn comprising:

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  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
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US733516A 1968-05-31 1968-05-31 Process for producing carbonized fibrous products Expired - Lifetime US3663173A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040044705A1 (en) * 2002-08-30 2004-03-04 Alacritus, Inc. Optimized disk repository for the storage and retrieval of mostly sequential data
US20090068545A1 (en) * 2007-09-11 2009-03-12 Korea Institute Of Energy Research Method of manufacturing cellulose electrode for fuel cells, cellulose electrode manufactured thereby, and use of cellulose fibers as fuel cell electrodes
EP2077151A1 (en) * 2008-01-03 2009-07-08 Korea Institute of Energy Research Catalyst support using cellulose fibers, preparation method thereof, supported catalyst comprising nano-metal catalyst supported on carbon nanotubes directly grown on surface of the catalyst support and method of preparing the supported catalyst

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2913802A (en) * 1953-07-16 1959-11-24 Johns Manville Thermal modification of acrylonitrile yarns
US3011981A (en) * 1958-04-21 1961-12-05 Soltes William Timot Electrically conducting fibrous carbon
US3041207A (en) * 1959-01-19 1962-06-26 Eastman Kodak Co Fire retardant coating and product resulting therefrom
US3235323A (en) * 1960-04-14 1966-02-15 Minnesota Mining & Mfg Heat-resistant black fibers and fabrics derived from rayon
US3294489A (en) * 1961-12-19 1966-12-27 Hitco Process for preparing carbon fibers
US3412062A (en) * 1964-04-24 1968-11-19 Nat Res Dev Production of carbon fibres and compositions containing said fibres
US3449077A (en) * 1967-02-13 1969-06-10 Celanese Corp Direct production of graphite fibers
US3454362A (en) * 1965-03-16 1969-07-08 Union Carbide Corp Process for producing fibrous graphite
US3529934A (en) * 1967-01-06 1970-09-22 Nippon Carbon Co Ltd Process for the preparation of carbon fibers
US3540848A (en) * 1967-07-12 1970-11-17 Hitco Continuous process for preparing electrically conductive carbonaceous fibers

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2913802A (en) * 1953-07-16 1959-11-24 Johns Manville Thermal modification of acrylonitrile yarns
US3011981A (en) * 1958-04-21 1961-12-05 Soltes William Timot Electrically conducting fibrous carbon
US3041207A (en) * 1959-01-19 1962-06-26 Eastman Kodak Co Fire retardant coating and product resulting therefrom
US3235323A (en) * 1960-04-14 1966-02-15 Minnesota Mining & Mfg Heat-resistant black fibers and fabrics derived from rayon
US3294489A (en) * 1961-12-19 1966-12-27 Hitco Process for preparing carbon fibers
US3412062A (en) * 1964-04-24 1968-11-19 Nat Res Dev Production of carbon fibres and compositions containing said fibres
US3454362A (en) * 1965-03-16 1969-07-08 Union Carbide Corp Process for producing fibrous graphite
US3529934A (en) * 1967-01-06 1970-09-22 Nippon Carbon Co Ltd Process for the preparation of carbon fibers
US3449077A (en) * 1967-02-13 1969-06-10 Celanese Corp Direct production of graphite fibers
US3540848A (en) * 1967-07-12 1970-11-17 Hitco Continuous process for preparing electrically conductive carbonaceous fibers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Schmidt et al.; Chem. Eng. Progress Vol. 58, No. 10, Oct. 1962, pp. 42 50 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040044705A1 (en) * 2002-08-30 2004-03-04 Alacritus, Inc. Optimized disk repository for the storage and retrieval of mostly sequential data
US20090068545A1 (en) * 2007-09-11 2009-03-12 Korea Institute Of Energy Research Method of manufacturing cellulose electrode for fuel cells, cellulose electrode manufactured thereby, and use of cellulose fibers as fuel cell electrodes
EP2037517A1 (en) * 2007-09-11 2009-03-18 Korea Institute of Energy Research Method of manufacturing cellulose electrode for fuel cells using direct growth of carbon nanotubes and chemical vapor deposition for supporting of platinum nano-catalyst, cellulose electrode manufactured thereby, and use of cellulose fibers as fuel cell electrodes
US8221830B2 (en) 2007-09-11 2012-07-17 Korea Institue of Energy Research Method of manufacturing cellulose electrode for fuel cells, cellulose electrode manufactured thereby, and use of cellulose fibers as fuel cell electrodes
EP2077151A1 (en) * 2008-01-03 2009-07-08 Korea Institute of Energy Research Catalyst support using cellulose fibers, preparation method thereof, supported catalyst comprising nano-metal catalyst supported on carbon nanotubes directly grown on surface of the catalyst support and method of preparing the supported catalyst

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GB1259024A (enrdf_load_stackoverflow) 1972-01-05

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