EP0026647B1 - Brai à mésophase, procédés pour sa production et fibres fabriquées à partir de celui-ci - Google Patents

Brai à mésophase, procédés pour sa production et fibres fabriquées à partir de celui-ci Download PDF

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Publication number
EP0026647B1
EP0026647B1 EP19800303384 EP80303384A EP0026647B1 EP 0026647 B1 EP0026647 B1 EP 0026647B1 EP 19800303384 EP19800303384 EP 19800303384 EP 80303384 A EP80303384 A EP 80303384A EP 0026647 B1 EP0026647 B1 EP 0026647B1
Authority
EP
European Patent Office
Prior art keywords
mesophase
pitch
solvent extraction
mesophase pitch
toluene
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19800303384
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German (de)
English (en)
Other versions
EP0026647A1 (fr
Inventor
Irwin Charles Lewis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BP Corp North America Inc
Original Assignee
Union Carbide Corp
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Filing date
Publication date
Application filed by Union Carbide Corp filed Critical Union Carbide Corp
Publication of EP0026647A1 publication Critical patent/EP0026647A1/fr
Application granted granted Critical
Publication of EP0026647B1 publication Critical patent/EP0026647B1/fr
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
    • C10C3/00—Working-up pitch, asphalt, bitumen
    • 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
    • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues

Definitions

  • the invention relates to a process for producing a mesophase pitch and particularly relates to a process for producing a mesophase pitch containing at least about 70% by weight mesophase.
  • mesophase pitch has been known to be suitable for producing carbon fibers having excellent properties suitable for commercial exploitation. It is known that mesophase derived carbon fibers are lightweight, strong, stiff, electrically conductive and both chemically and thermally inert. The mesophase derived carbon fibers perform well as reinforcements in composites and have found use in aerospace applications and quality sporting equipment.
  • carbon fibers have been primarily made from three types of precursor materials; rayon, polyacrylonitrile (PAN), and pitch.
  • PAN polyacrylonitrile
  • pitch is attractive economically.
  • carbon fibers produced from mesophase pitch exhibit high preferred molecular orientation and relatively excellent mechanical properties.
  • pitch is to be understood as used in the instant art and generally refers to a carbonaceous residue consisting of a complex mixture of primarily aromatic organic compounds which are solid at room temperature and exhibit a relatively broad melting or softening temperature range. When cooled from the melt, the pitches behave as glasses.
  • mesophase is to be understood as used in the instant art and generally is synonymous with liquid crystal. That is, a state of matter which is intermediate between crystalline solid and a normal liquid. Ordinarily, a material in the mesophase state exhibits both anisotropic and liquid properties.
  • mesophase-containing pitch is a pitch containing less than about 40% by weight mesophase and the non-mesophase portion or isotropic phase is the continuous phase.
  • mesophase pitch is a pitch containing more than about 40% by weight mesophase and is capable of forming a continuous anisotropic phase when dispersed by agitation or the like in accordance with the prior art.
  • the conventional method for preparing mesophase pitch from a precursor pitch includes heat treating at a temperature greater than 350°C to effect thermal polymerization. This process produces large molecular weight molecules capable of forming mesophase.
  • a typical conventional method is carried out using reactors maintained at about 400°C for about 20 hours.
  • the properties of the final material can be controlled by the reaction temperature, heat-treatment time, and volatilization rate.
  • the presence of the high molecular weight fraction results in a melting point of the mesophase pitch of at least 330°C. An even higher temperature is needed to transform the mesophase pitch into fibers. This is termed "spinning" in the Art.
  • the amount of mesophase in pitch can be evaluated by known methods using polarized light microscopy.
  • the presence of homogeneous bulk mesophase regions can be visually observed by polarized light microscopy and quantitatively determined by the method disclosed in the aforementioned Chwastiak patent.
  • the criteria of insolubility in certain organic solvents such as quinoline and pyridine was used to estimate mesophase content.
  • certain non-mesophase insolubles could, however, be present in the precursor pitch certain non-mesophase insolubles and it is a common practice to remove these insolubles before treating the precursor pitch.
  • %Q.I refers to quinoline insolubles of a pitch quinoline extracted at 75°C.
  • %P.I refers to pyridine insolubles of a pitch by Soxhlet extraction in boiling pyridine at about 115°C.
  • Softening point or softening temperature of a pitch is related to its molecular weight constitution, the presence of a large amount of high molecular weight components generally tends to raise the softening temperature. It is a common practice in the art to characterize in part a precursor pitch by its softening point. For mesophase pitches, the softening point is used to determine suitable spinning temperature. Generally, the spinning temperature is about 40°C or more higher than the softening temperature.
  • Mettler softening point procedure is widely accepted as the standard for evaluating precursor pitches. This procedure can be adapted for use on mesophase pitches.
  • the softening temperature of a mesophase pitch can also be determined by hot stage microscopy.
  • the mesophase pitch is heated on a microscope hot stage in an inert atmosphere under polarized light.
  • the temperature of the mesophase pitch is raised under a controlled rate and the temperature at which the mesophase pitch commences to deform is noted as the softening temperature.
  • softening point or softening temperature will refer to the temperature determined by the Mettler procedure for both precursor and mesophase pitches.
  • a process for producing a mesophase pitch containing at least 70% by weight mesophase which comprises solvent extracting a carbonaceous precursor pitch capable of forming a large domained mesophase pitch by a conventional thermal process, characterised by using as a solvent a N,N-dimethylformamide, carbondisulfide, or a mixture of toluene and petroleum ether and by the absence of a heating step subsequent to the solvent extraction.
  • the mesophase pitch produced in accordance with the invention possesses x-ray properties of interlayer spacing Co/2 of less than 3.60 Angstroms and an apparent stack height Lc of greater than 20 Angstroms.
  • the mesophase pitch produced in accordance with the invention contains at least 90% by weight mesophase and more preferably 100% by weight mesophase.
  • the solvent extraction utilized in the process of the present invention may, for example, include a sequence of solvent extraction steps. Further, when the solvent extraction is carried out utilizing a mixture of toluene and petroleum ether, this may, for example, be effected by carrying out a solvent extraction using toluene and, as a separate step, carrying out a solvent extraction using petroleum ether.
  • a mesophase pitch containing a predetermined amount of mesophase may, for example, be obtained by blending together soluble and insoluble portions resulting from the solvent-extraction.
  • the solvent extraction utilized in the process of the present invention may, for example, be preceded by distilling the carbonaceous pitch.
  • a fiber e.g. a carbonised fiber
  • the fibre may be formed without any chemical operations e.g. by spinning.
  • the spinning is at a temperature less than 370°C.
  • Conventional spinning does not subject the pitch to a chemical change for a temperature below 370°C for the period of time the mesophase pitch is at that elevated temperature.
  • the instant invention allows the formation of a pitch fiber from a carbonaceous pitch without any chemical operations.
  • the carbonaceous precursor pitch is heated to effect polymerization.
  • the resultant mesophase pitch is characterized by a molecular weight distribution which contains two major peaks.
  • the low molecular weight peak corresponds to components of the precursor pitch and the high molecular weight peak corresponds to the molecules produced by the thermal polymerization.
  • the mesophase pitch produced in accordance with the present invention possesses a molecular weight distribution having a single major peak generally positioned between the two peaks which would have arisen if the thermal polymerization had been carried out.
  • the carbonaceous precursor pitch suitable for carrying out the invention should be a precursor pitch capable of forming a large-domained mesophase pitch by conventional thermal processes as set forth in the aforementioned Singer Patent No. 4,005,183.
  • the suitability of any carbonaceous pitch can be determined in a straight forward manner in accordance with the teachings herein.
  • a commercially available petroleum pitch was used in a solvent extraction operation.
  • the petroleum pitch had a softening temperature of about 130°C and has 0% P.I. and contained no mesophase.
  • a commercially available pitch different from the Example 1 was selected.
  • the petroleum pitch had a softening temperature of about 123°C and has about 0% P.I. and contained no mesophase.
  • Example 1 The operations of the Example 1 were repeated except that the solvent was a 1:2 mixture of petroleum ether and toluene. About 14% by weight yield was obtained and the yield had a softening temperature of about 239°C and had about 3% P.I. and contained about 100% by weight mesophase.
  • Example 2 was repeated except that the solvent was a 1:1 mixture of petroleum ether and toluene.
  • the yield was about 32% and contained about 50% by weight mesophase.
  • the mesophase pitch of the Example 2 was spun into fibers on a monofilament spinning machine at about 290°C.
  • the fibers had a diameter of about 20 microns and were thermoset by heating them in air at 2°C per minute to about 375°C.
  • the thermoset fibers were examined by polarized light microscopy and were determined to contain about 100% anisotropic state.
  • the thermoset fibers were carbonized to 1700°C in an inert atmosphere in accordance with conventional methods and tests on the carbonized fibers exhibited a modulus of about 25x10 6 psi (172 GPa) and 25,000 psi (1.72 GPa) tensile strength.
  • the petroleum pitch of the Example 2 was solvent extracted with petroleum ether.
  • the yield was about 77% by weight and contained no mesophase.
  • Further solvent extraction with toluene in accordance with the Example 2 produced about 1% by weight yield which contained about 100% by weight mesophase.
  • Solvent extraction was carried out on a coal tar pitch having a softening temperature of about 125°C and about 0% mesophase. At room temperature, 60 grams of pitch was stirred with 1200 ml of toluene for about two hours. The yield was about 47% by weight. The yield had a softening temperature of about 318°C, exhibited about 53% P.I., and contained about 60% by weight mesophase.
  • Tests were carried out to determine mesophase content as a function of blending soluble and insoluble portions of the solvent extracted pitch.
  • Tests were carried out on the various yields from the examples to determine the characteristics of both the molecular weight distributions and x-ray diffraction.
  • Table 1 shows the results of these tests for mesophase pitches of various examples.
  • the molecular weight distribution data was obtained in accordance with the aforementioned Lewis et al. Patent No. 3,976,729 and Chwastiak British Patent 2,005,298.
  • the solvent employed in the gel permeation chromatographic procedure was quinoline.
  • Table 2 shows mesophase pitches produced by conventional thermal processes for pitches used in various examples.
  • Table 3 shows x-ray data for precursor pitches prior to any operations.
  • the mesophase pitch of the Example 2 was melted at a temperature of about 300°C and stirred for about 30 minutes in an inert atmosphere in order to remove the solvent.
  • the product was spun into monofilaments at a temperature of about 300°C.
  • the as-spun fibers had a diameter of 15 pm and 25 ⁇ m.
  • the 25 um fibers were crushed to a powder and examined by x-ray.
  • the Co/2 was measured as 3.54 Anstrom and Lc was measured as 34 Angstrom.
  • the preferred orientation of the as-spun fibers was measured as being about 30°.
  • the as-spun fibers made by conventional processes as disclosed in the aforementioned Singer Patent No. 4,032,430 had a Co/2 of from 3.45 to 3.55 Angstroms, Lc of from 30 to 50 Angstroms, and a preferred orientation of from 25° to 30°.
  • the 15 ⁇ m fibers were thermoset by heating in air at 2° per minute to about 375°C.
  • the thermoset fibers were examined and contained about 100% anisotropic state.
  • the thermoset fibers were carbonized to 1700°C in an inert atmosphere in accordance with conventional methods and the carbonized fibers exhibited a modulus of about 28x106 psi (193 GPa) and a tensile strength of 273,000 psi (1.88 GPa).

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Materials Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Textile Engineering (AREA)
  • Working-Up Tar And Pitch (AREA)
  • Inorganic Fibers (AREA)

Claims (8)

1. Procédé de production d'un brai à mésophase contenant au moins 70% en poids de mésophase, qui consiste à extraire au solvant un brai précurseur carboné capable de former un brai à mésophase à grand domaine par un procédé thermique classique, caractérisé par l'utilisation comme solvant de N,N-diméthyl- formamide, de sulfure de carbone ou d'un mélange de toluène et d'éther de pétrole et par l'absence d'une étape de chauffage à la suite de l'extraction au solvant.
2. Procédé suivant la revendication 1, caractérisé en ce que l'extraction au solvant comprend une succession d'étapes d'extraction au solvant.
3. Procédé suivant la revendication 1 ou 2, caractérisé par l'utilisation dans l'extraction au solvant d'un mélange de toluène et d'éther de pétrole.
4. Procédé suivant la revendication 3, caractérisé en ce que l'extraction au solvant utilisant un mélange de toluène et d'éther de pétole est effectuée par la conduite d'une opération d'extraction au solvant utilisant du toluène et, en tant qu'opération séparée, la conduite d'une extraction au solvant utilisant l'éther de pétrole.
5. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce qu'un brai à mésophase contenant une quantité prédéterminée de mésophase est obtenu en mélangeant des portions solubles et insolubles qui résultent de ladite extraction au solvant.
6. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que l'extraction au solvant est précédée d'une distillation dudit brai carboné.
7. Procédé suivant l'une quelconque des revendications précédentes, caractérisé par l'étape additionnelle de production d'une fibre à partir dudit brai à mésophase.
8. Procédé suivant l'une quelconque des revendications précédentes, caractérisé par l'étape additionnelle de production d'une fibre carbonisée à partir dudit brai à mésophase.
EP19800303384 1979-09-28 1980-09-26 Brai à mésophase, procédés pour sa production et fibres fabriquées à partir de celui-ci Expired EP0026647B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US7989179A 1979-09-28 1979-09-28
US79891 1979-09-28

Publications (2)

Publication Number Publication Date
EP0026647A1 EP0026647A1 (fr) 1981-04-08
EP0026647B1 true EP0026647B1 (fr) 1985-05-22

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19800303384 Expired EP0026647B1 (fr) 1979-09-28 1980-09-26 Brai à mésophase, procédés pour sa production et fibres fabriquées à partir de celui-ci

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EP (1) EP0026647B1 (fr)
JP (1) JPS5657881A (fr)
DE (1) DE3070671D1 (fr)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57125289A (en) * 1981-01-28 1982-08-04 Toa Nenryo Kogyo Kk Preparation of optically anisotropic carbonaceous pitch
US4402928A (en) * 1981-03-27 1983-09-06 Union Carbide Corporation Carbon fiber production using high pressure treatment of a precursor material
JPS588786A (ja) * 1981-07-10 1983-01-18 Mitsubishi Oil Co Ltd 炭素繊維原料用ピツチの製造方法
US4464248A (en) * 1981-08-11 1984-08-07 Exxon Research & Engineering Co. Process for production of carbon artifact feedstocks
JPS5837084A (ja) * 1981-08-28 1983-03-04 Toa Nenryo Kogyo Kk 低軟化点の光学的異方性炭素質ピッチの製造方法
JPS5852386A (ja) * 1981-09-24 1983-03-28 Mitsubishi Oil Co Ltd 炭素繊維原料ピツチの製造方法
JPS5936725A (ja) * 1982-08-24 1984-02-29 Agency Of Ind Science & Technol 炭素繊維製造用ピツチ組成物
US4590055A (en) * 1982-08-24 1986-05-20 Director-General Of The Agency Of Industrial Science And Technology Pitch-based carbon fibers and pitch compositions and precursor fibers therefor
US4503026A (en) * 1983-03-14 1985-03-05 E. I. Du Pont De Nemours And Company Spinnable precursors from petroleum pitch, fibers spun therefrom and method of preparation thereof
CA1224604A (fr) * 1983-03-28 1987-07-28 E. I. Du Pont De Nemours And Company Melange precuseur pour la fabrication d'articles a base de carbone, et sa preparation
DE3509861C2 (de) * 1984-03-26 1986-03-06 Idemitsu Kosan Co. Ltd., Tokio/Tokyo Pechmaterial für einen kohlenstoffhaltigen Formkörper und Verfahren zu seiner Herstellung
DE3441727A1 (de) * 1984-11-15 1986-05-15 Bergwerksverband Gmbh, 4300 Essen Verfahren zur herstellung von anisotropen kohlenstoffasern
JPH0670220B2 (ja) * 1984-12-28 1994-09-07 日本石油株式会社 炭素繊維用ピッチの製造法
US5259947A (en) * 1990-12-21 1993-11-09 Conoco Inc. Solvated mesophase pitches
JPH0517782A (ja) * 1991-07-09 1993-01-26 Tonen Corp 高圧縮強度炭素繊維製造用液晶ピツチ及び高圧縮強度炭素繊維の製造方法
WO1993024590A1 (fr) * 1992-06-04 1993-12-09 Conoco Inc. Procede de production de brai mesophase solvate, et articles en carbone obtenus a partir de ce dernier
WO2019240949A1 (fr) * 2018-06-15 2019-12-19 Exxonmobil Research And Engineering Company Modification de la dépendance à la température de la viscosité du brai pour la fabrication d'articles en carbone
AU2021420739A1 (en) * 2021-01-13 2023-06-15 ExxonMobil Technology and Engineering Company Methods for enhancing the formation of mesophase in pitch compositions derived from hydrocarbon feedstocks

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3919387A (en) * 1972-12-26 1975-11-11 Union Carbide Corp Process for producing high mesophase content pitch fibers
US4208267A (en) * 1977-07-08 1980-06-17 Exxon Research & Engineering Co. Forming optically anisotropic pitches
US4219404A (en) * 1979-06-14 1980-08-26 Exxon Research & Engineering Co. Vacuum or steam stripping aromatic oils from petroleum pitch

Also Published As

Publication number Publication date
JPH0157715B2 (fr) 1989-12-07
JPS5657881A (en) 1981-05-20
DE3070671D1 (en) 1985-06-27
EP0026647A1 (fr) 1981-04-08

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