EP0430689A1 - Brai en phase méso pour la préparation d'objets en carbone - Google Patents
Brai en phase méso pour la préparation d'objets en carbone Download PDFInfo
- Publication number
- EP0430689A1 EP0430689A1 EP90312978A EP90312978A EP0430689A1 EP 0430689 A1 EP0430689 A1 EP 0430689A1 EP 90312978 A EP90312978 A EP 90312978A EP 90312978 A EP90312978 A EP 90312978A EP 0430689 A1 EP0430689 A1 EP 0430689A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pitch
- carbon
- mesophase
- mesophase pitch
- fibers
- 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.)
- Granted
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- 239000011302 mesophase pitch Substances 0.000 title claims abstract description 54
- 239000003575 carbonaceous material Substances 0.000 title claims description 13
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 40
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 34
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 16
- 125000003118 aryl group Chemical group 0.000 claims abstract description 11
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 239000011295 pitch Substances 0.000 abstract description 69
- 239000000835 fiber Substances 0.000 abstract description 37
- 238000010438 heat treatment Methods 0.000 abstract description 18
- 150000002790 naphthalenes Chemical class 0.000 abstract description 11
- 239000012298 atmosphere Substances 0.000 abstract description 9
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 abstract description 7
- 239000011261 inert gas Substances 0.000 abstract description 6
- 230000000379 polymerizing effect Effects 0.000 abstract description 3
- 229910002804 graphite Inorganic materials 0.000 abstract 1
- 239000010439 graphite Substances 0.000 abstract 1
- WTEOIRVLGSZEPR-UHFFFAOYSA-N boron trifluoride Chemical compound FB(F)F WTEOIRVLGSZEPR-UHFFFAOYSA-N 0.000 description 42
- 238000000034 method Methods 0.000 description 26
- 229920000049 Carbon (fiber) Polymers 0.000 description 22
- 239000004917 carbon fiber Substances 0.000 description 22
- 229910015900 BF3 Inorganic materials 0.000 description 21
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 20
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 19
- 238000009987 spinning Methods 0.000 description 19
- QPUYECUOLPXSFR-UHFFFAOYSA-N 1-methylnaphthalene Chemical compound C1=CC=C2C(C)=CC=CC2=C1 QPUYECUOLPXSFR-UHFFFAOYSA-N 0.000 description 18
- 238000006116 polymerization reaction Methods 0.000 description 17
- 239000003054 catalyst Substances 0.000 description 15
- 238000003763 carbonization Methods 0.000 description 12
- 239000012071 phase Substances 0.000 description 11
- 230000006641 stabilisation Effects 0.000 description 9
- 238000011105 stabilization Methods 0.000 description 9
- 239000007858 starting material Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 230000009257 reactivity Effects 0.000 description 5
- QNLZIZAQLLYXTC-UHFFFAOYSA-N 1,2-dimethylnaphthalene Chemical compound C1=CC=CC2=C(C)C(C)=CC=C21 QNLZIZAQLLYXTC-UHFFFAOYSA-N 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 230000004927 fusion Effects 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 229920002239 polyacrylonitrile Polymers 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000011337 anisotropic pitch Substances 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000003208 petroleum Substances 0.000 description 3
- 239000002798 polar solvent Substances 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- APQSQLNWAIULLK-UHFFFAOYSA-N 1,4-dimethylnaphthalene Chemical compound C1=CC=C2C(C)=CC=C(C)C2=C1 APQSQLNWAIULLK-UHFFFAOYSA-N 0.000 description 2
- YGYNBBAUIYTWBF-UHFFFAOYSA-N 2,6-dimethylnaphthalene Chemical compound C1=C(C)C=CC2=CC(C)=CC=C21 YGYNBBAUIYTWBF-UHFFFAOYSA-N 0.000 description 2
- QIMMUPPBPVKWKM-UHFFFAOYSA-N 2-methylnaphthalene Chemical compound C1=CC=CC2=CC(C)=CC=C21 QIMMUPPBPVKWKM-UHFFFAOYSA-N 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000003085 diluting agent Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000005984 hydrogenation reaction Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- -1 polycyclic aromatic compound Chemical class 0.000 description 2
- 239000002685 polymerization catalyst Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000000638 solvent extraction Methods 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- 239000005967 1,4-Dimethylnaphthalene Substances 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- XOCUXOWLYLLJLV-UHFFFAOYSA-N [O].[S] Chemical compound [O].[S] XOCUXOWLYLLJLV-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 150000007514 bases Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 239000011294 coal tar pitch Substances 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000011437 continuous method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 239000003701 inert diluent Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002074 melt spinning Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen(.) Chemical compound [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 238000000655 nuclear magnetic resonance spectrum Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011271 tar pitch Substances 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
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
- D01F9/15—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from coal pitch
-
- 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
- D01F9/155—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from petroleum pitch
Definitions
- the present invention relates to mesophase pitch for use in the production of high-performance carbon fibers and other carbon materials.
- High-performance carbon fibers are commercially produced chiefly from PAN (polyacrylonitrile).
- PAN polyacrylonitrile
- PAN is expensive and does not show high yield in carbonization. It has recently been found that carbon fibers which have comparable or better characteristics than those prepared from PAN can be produced from inexpensive pitch, and active efforts are being made to commercialize this method.
- pitch there are two types of pitch that can be used as a starting material for the manufacture of carbon materials; isotropic pitch and anisotropic pitch.
- Carbon fibers produced from isotropic pitch are inexpensive but they suffer from the disadvantage of low strength due to poor molecular orientation. Therefore, high-performance carbon products cannot be produced from isotropic pitch.
- carbon fibers produced from anisotropic pitch called "mesophase pitch” have a higher degree of molecular orientation and exhibit improved mechanical properties in terms of strength and modulus of elasticity. Therefore, with a view to producing high-performance carbon fibers, extensive studies are being conducted on the production of mesophase pitch from catalytic cracked petroleum pitch, petroleum tar pitch or coal tar pitch.
- This oriented structure is maintained without being disturbed during the stage of subsequent "stabilization” in which the surface of fibers is oxidized by gradual heating under an air current and during the stage of "carbonization” in which the stabilized fibers are heat-treated in an inert gas atmosphere at temperatures not lower than 1,000°C. It has been confirmed by many experiments that this effect contributes to the production of highly oriented, high-performance carbon fibers.
- mesophase The portion of pitch which has an optically anisotropic phase (this portion is hereinafter referred to as "mesophase") is insoluble in polar solvents such as quinoline and pyridine and it has so far been considered that mesophase is identical to the component which is insoluble in polar solvents.
- polar solvents such as quinoline and pyridine
- mesophase is identical to the component which is insoluble in polar solvents.
- mesophase contains both components which are insoluble and soluble in polar solvents.
- mesophase means that portion of a phase which shows optical anisotropy when observed under a polarizing microscope, and the proportion taken by the area of this optically anisotropic phase under observation with a polarizing microscope shall be called “the content of mesophase”, or more simply “the mesophase content”.
- the mesophase content of pitch is preferably at least 90%, more preferably 100%.
- an increase in the mesophase content generally causes an increase in the softening point and viscosity of the pitch and renders it difficult to perform spinning with consistent results.
- the high softening point and viscosity necessitate spinning at elevated temperatures but then the pitch is prone to thermal decomposition or condensation, and the resulting gases and infusible high-molecular weight substances make it difficult to continue spinning operations for a prolonged time with consistent results.
- U.S. Patent No. 4,472,265 shows a method in which the mesophase pitch is partially hydrogenated to reduce the degree of stacking of its molecules to an appropriate degree and the resulting "isotropic pitch" is subjected to spinning.
- Japanese Patent Public Disclosure No. 18421/1983 shows a method characterized by the use of a unique kind of pitch, or "premesophase" pitch which is isotropic during spinning but which turns anisotropic during carbonization.
- U.S. Patent No. 4,208,267 shows a method in which isotropic pitch is subjected to solvent extraction, followed by heating the insoluble matter at 230-400°C.
- the mesophase content of mesophase pitch for use in the production of carbon materials has to be increased in order to provide high performance in such aspects as strength and modulus of elasticity.
- the mesophase content of the pitch must also be increased for the purpose of facilitating spinning operations in the production of carbon fibers. Additional requirements include high heat stability during spinning operations, high stabilization reactivity of the spun fibers and high yield in carbonization. In the case of producing carbon materials, the yield of the carbon material produced by carbonization of the pitch must also be high.
- the mesophase pitch for use in the production of carbon materials is required to satisfy the following conditions: (1) high mesophase content, (2) high heat stability during spinning operations, (3) high stabilization reactivity, and (4) high yield in carbonization.
- the present inventors conducted intensive studies in order to develop mesophase pitch having the characteristics described above. As a result, the present inventors found that mesophase pitch that had a reasonable degree of polymerization and in which high proportions of the total carbon atoms were occupied by methyl groups and aromatic ring structures exhibited excellent performance. Since this pitch satisfies the four requirements set forth above, it is suitable for use in the production of high-performance carbon products and can be spun into fibers in an easy and consistent way. Furthermore, the spun fibers can be efficiently stabilized with the added advantage of high yield in subsequent carbonization. The present invention has been accomplished on the basis of these findings.
- the present invention relates to mesophase pitch for use in the production of carbon materials that has an average molecular weight of at least about 1,000 and a hydrogen-to-carbon atomic ratio of about 0.5-1.0, with an aromatic carbon ratio (fa) being at least about 0.7 and the methylic carbon content being at least about 4% of the total carbon atoms, and that has at least about 90% of an optically anisotropic phase.
- mesophase pitch from a condensed polycyclic hydrocarbon that contained naphthenic carbon in an amount of at least 7% of the total carbon atoms. Since this pitch satisfied the four requirements described above, the inventors filed a patent application on it, which is now U.S. Patent No. 4,891,126.
- the present inventors found that when naphthalene derivatives such as methylnaphthalene having at least one methyl group were polymerized, mesophase pitch that contained less than 7% naphthenic carbon atoms and which yet exhibited high performance could be produced. In particular, this mesophase pitch has higher stabilization reactivity than that described in U.S. Patent No. 4,891,126.
- the average molecular weight of the mesophase pitch of the present invention is measured with a vapor pressure osmometer using chloroform as a solvent.
- the solvent-soluble portion of the pitch dissolves in chloroform and its molecular weight is measured with a vapor pressure osmometer.
- the insoluble portion is made soluble by performing a hydrogenation reaction under mild conditions using metallic lithium and ethylenediamine, and its molecular weight is measured with the same vapor pressure osmometer. The results of the two measurements are used to determine the average molecular weight of the mesophase pitch.
- the mesophase pitch of the present invention has an average molecular weight of at least about 1,000, preferably about 1,000-1,700, as measured by the above-described method. If the average molecular weight is less than about 1,000, the degree of polymerization that can be achieved is too low to produce pitch having high mesophase content.
- the carbon and hydrogen contents of the mesophase pitch of the present invention are measured with an automatic analyzer (CHN coder) utilizing a detection technique that measures the thermal conductivity of combustion gases.
- the aromatic carbon ratio (fa) is measured by an IR absorption technique and the methylic carbon content by NMR.
- the hydrogen to carbon atomic ratio of the mesophase pitch for use in the production of carbon materials of the present invention is in the range of from about 0.5 to about 1.0, preferably from about 0.6 to about 1.0. If the atomic ratio of hydrogen to carbon is less than about 0.5, the resulting pitch suffers the problem of excessive dehydrogenation compared to polymerization and its softening point is so much increased as to render subsequent spinning and other processing operations difficult. If the hydrogen to carbon atomic ratio is higher than about 1.0, the resulting pitch has a low degree of orientation on account of insufficient degree of polymerization, and this makes it impossible to obtain carbon fibers or other carbon materials having desired performance in such aspects as strength and modulus of elasticity.
- the aromatic carbon ratio (fa) is the ratio of the number of carbon atoms in aromatic ring structures to the total number of carbon atoms present.
- the pitch of the present invention has an fa of at least about 0.7, preferably between about 0.75 and about 0.87. If the value of fa is less than about 0.7, the molecules that constitute a mesophase do not have a high degree of planar structure and it is difficult to achieve consistent production of pitch having a high content of an optically anisotropic phase.
- the methylic carbon content of the pitch of the present invention is at least about 4%, preferably at least about 5%, of the total carbon atoms present. If the methylic carbon content is less than about 4%, the stabilization reactivity is so low that it takes an unduly long time to complete the stabilizing treatment, with the increased chance of fusion of occurring between stabilized fibers.
- the optically anisotropic phase (mesophase) of the pitch of the present invention is measured with a polarizing microscope.
- the pitch of the present invention has a mesophase content of at least about 90%, preferably at least about 95%. More preferably, substantially all part of the pitch is composed of a mesophase. If the pitch has a mesophase content of less than about 90%, carbon fibers or other carbon materials that are formed of it will have only low performance in such aspects as strength and modulus of elasticity. From the spinning viewpoint, too, the mesophase content must be at least about 90%.
- the mesophase pitch of the present invention can be produced by polymerizing naphthalene derivatives having at least one methyl group in the presence of hydrogen fluoride and boron trifluoride.
- Illustrative naphthalene derivatives that can be used as the starting material include methylnaphthalene, dimethylnaphthalene and mixtures thereof. Materials containing these naphthalene derivatives are also usable and they include various petroleum fractions, the residual oil originating from petroleum processing steps, and coal tar fractions.
- a hydrogen fluoride/boron trifluoride catalyst is used as a catalyst for polymerizing these naphthalene derivatives.
- particularly suitable starting materials are those which have low contents of nitrogen ⁇ , sulfur ⁇ and oxygen-containing compounds, all being basic compounds that strongly bind to the hydrogen fluoride/boron trifluoride catalyst.
- the polymerization catalyst is preferably used in such an amount that from about 0.1 to about 20 moles of hydrogen fluoride and from about 0.05 to about 1.0 mole of boron trifluoride are present per mole of the naphthalene derivative.
- Hydrogen fluoride when used together with boron trifluoride (BF3), forms a strong protic acid, which reacts with the basic naphthalene derivative to form a complex.
- the temperature for obtaining the desired mesophase by polymerization reaction ranges from about 180 to about 400°C, preferably from about 250 to about 320°C. If the temperature is higher than about 400°C, polymerization proceeds excessively and the resulting pitch will have an unduly high softening point. If the temperature is lower than about 180°C, mesophase pitch having a mesophase content of at least 90% is not attainable.
- the time required to complete the polymerization reaction varies with the type of starting material used, the temperature and the amount of catalyst used, but it is typically within the range of from about 5 to about 300 minutes, preferably from about 30 to about 240 minutes.
- the pressure for the polymerization reaction generally ranges from about 5 to about 100 atmospheres, preferably from about 20 to about 50 atmospheres.
- the polymerization reaction is performed by mixing under agitation the starting material and the catalyst fed into a corrosion-resistant reactor equipped with a stirrer.
- the procedures of reaction may be batchwise or continuous.
- naphthalene derivative (Nd) fed as the starting material forms a complex when mixed with the catalyst and undergoes rapid polymerization to form a polymer in complex form according to the following scheme: HF + BF3 + (Nd) n ⁇ ⁇ H+(Nd) n BF4 ⁇ (1)
- the resulting polymer in complex form is in equilibrium as shown by equation (1), so after completion of the polymerization the volatile components, HF and BF3, are distilled off at the polymerization temperature and recovered as catalyst components. At the same time, some volatile fractions are recovered and the polymerized pitch is separated.
- Catalyst separation by a batch system consists of holding the polymerization temperature after the polymerization reaction has been completed, and withdrawing HF and BF3 as a vapor phase from the reactor, with the polymer recovered as molten pitch.
- the heating effected for this purpose may be indirect (external heating through a jacket, etc.) or direct (by introducing the heated vapor of a diluent such as benzene, toluene or halogenated hydrocarbon which are comparatively inert to the catalyst).
- Catalyst separation may also be performed by a continuous method in a distillation column, with the inert diluent being refluxed, which is continuously supplied with the polymerization reaction solution so as to extract the HF and BF3 vapors from the top of the column, with the pitch being recovered from the bottom of the column in the form of a solution in the diluent.
- the temperature necessary for recovering the catalyst is the same as the temperature for polymerization, whereas the pressure for the catalyst recovery is generally within the range of from about 0 to about 30 atmospheres, preferably from about 1 to about 5 atmospheres.
- the pitch obtained by the procedure described above is characterized by high mesophase content and the presence of many carbon atoms in aromatic ring structures as well as in methyl groups.
- This pitch also has a low softening point which is in the range of 200-250°C as measured by a micromelting point method.
- the pitch described above is mesophase pitch which is substantially free of HF and BF3 and which has an anisotropic phase of at least about 90%. It can be used as a starting material for the production of carbon fibers and other carbon materials without being subjected to any special treatment.
- this mesophase pitch can be readily spun into fibers at a spinning temperature of from about 280 to about 340°C.
- the spun pitch fibers have such a high stabilization reactivity that they can be satisfactorily stabilized by heating up to a temperature of about 300°C at a rate of about 7°C/min under an air current. This ease of stabilization can be ascribed to the high content of methyl-derived carbon atoms in the pitch.
- Carbon fibers may be produced from the pitch of the present invention by the following procedures: the pitch is first extruded through a nozzle (ca. 0.25 ⁇ m) in a nitrogen atmosphere at a pressure of from about 1 to about 3 kg/cm2G and at a temperature of from about 280 to about 340°C and the filaments are wound up on a roll at a take-up speed of, say, about 500 m/min; then, the filaments are stabilized by heating from ambient temperature to a temperature between about 200 and about 350°C at a typical rate of from about 1 to about 7°C/min under an air current; finally, the stabilized fibers are carbonized or graphitized by heating to about 1,000°C or above at a typical rate of about 10°C/min in an inert gas stream such as nitrogen.
- the mesophase pitch of the present invention has the following advantages.
- the mesophase pitch of the present invention can be stabilized without employing any complex and costly steps such as filtration of infusible matter at high temperature and solvent extraction thereof.
- the pitch of the present invention is composed of a substantially homogeneous mesophase and can be spun into carbon fibers at a temperature between about 280 and about 340°C, which is appreciably lower than the conventionally employed temperature range.
- the mesophase pitch of the present invention can be spun into fibers at a temperature that is much lower than the point at which marked thermal decomposition or polycondensation occurs (ca. 400°C). Therefore, the spinnability of the pitch is good enough to resist deterioration during spinning and carbon fibers of consistent quality can be produced.
- the pitch of the present invention can be spun at high speed and the spun pitch fibers have so few defects that carbon fibers of high strength can be produced.
- the mesophase pitch of the present invention has a high anisotropic phase content of at least about 90%, so carbon fibers produced from this pitch are characterized by well developed orientation in the direction of fiber axis and exhibit high modulus of elasticity.
- the mesophase pitch of the present invention has a high H/C atomic ratio and the proportion of methylic carbon in the total carbon content is high enough to enhance the adaptability of the pitch for stabilization, thereby enabling completely unfusible (stabilized) fibers to be obtained in a shorter period of time.
- the mesophase pitch of the present invention ensures high yield in carbonization because of its high degree of polymerization.
- the present invention offers great benefits to industry.
- ⁇ -Methylnaphthalene (1 mole), HF (0.5 moles) and BF3 (0.2 moles) were charged into a 0.5-l acid-resistant autoclave, and after raising the temperature in the autoclave to 270°C, reaction was performed for 4 hours. Thereafter, the release valve on the autoclave was opened so that substantially all of the HF and BF3 charged could be recovered in a gaseous form at an atmospheric pressure. Thereafter, nitrogen was blown into the autoclave to remove the low-boiling point components. The yield of the pitch obtained was 76% of the weight of the ⁇ -methylnaphthalene supplied.
- this pitch When observed with a polarizing microscope, this pitch was found to be 100% anisotropic mesophase pitch with a softening point of 240°C, an average molecular weight of 1360, a H/C atomic ratio of 0.65, and an aromatic carbon ratio (fa) of 0.82, with the methylic carbon content being 6% of the total carbon atoms.
- the naphthenic carbon content of this pitch was 3% of the total carbon. All of these parameters except naphthenic carbon content were measured by the methods described hereinabove. The naphthenic carbon content was measured by an NMR spectrum technique.
- This mesophase pitch could be spun into fibers at 310°C and at a take-up speed of 500 m/min without any fiber being broken during spinning.
- the fibers could be readily stabilized by heating to 300°C at a rate of 7°C/min. The stabilized fibers were entirely free from fusion.
- the stabilized fibers were heated to 1,000°C at a rate of 10°C/min in an inert gas atmosphere so as to produce carbon fibers having a diameter of 10 ⁇ m.
- the yield in carbonization was 90%, and the carbon fibers produced had a tensile strength of 280 kgf/mm2 and a modulus of elasticity of 22 tf/mm2.
- This mesophase pitch could be spun into fibers at 280°C and at a take-up speed of 500 m/min without any fiber being broken during spinning.
- the fibers could be readily stabilized by heating to 280°C at a rate of 7°C/min. The stabilized fibers were entirely free from fusion.
- the stabilized fibers were heated to 1,000°C at a rate of 10°C/min in an inert gas atmosphere so as to produce carbon fibers having a diameter of 8 ⁇ m.
- the yield in carbonization was 90% and the carbon fibers produced had a tensile strength of 320 kgf/mm2 and a modulus of elasticity of 20 tf/mm2.
- This mesophase pitch could be spun into fibers at 310°C and at a take-up speed of 500 m/min without any fiber being broken during spinning.
- the fibers could be readily stabilized by heating to 270°C at a rate of 7°C/min. The stabilized fibers were entirely free from fusion.
- the stabilized fibers were heated to 1,000°C at a rate of 10°C/min in an inert gas atmosphere so as to produce carbon fibers having a diameter of 10 ⁇ m.
- the yield in carbonization was 90%, and the carbon fibers produced had a tensile strength of 290 kgf/mm2 and a modulus of elasticity of 23 tf/mm2.
- ⁇ -Methylnaphthalene (1 mole), HF (3 moles) and BF3 (0.5 moles) were charged into a 3-l acid-resistant autoclave, and reaction was performed for 3 hours at a raised temperature of 80°C. Thereafter, the release valve on the autoclave was opened and gradual heating to 180-200°C was conducted at one atmosphere so that substantially all of the HF and BF3 charged could be recovered in a gaseous form. Thereafter, the pitch in molten state was withdrawn from the autoclave. This pitch had a softening point of 72°C and contained no mesophase.
- This pitch was heat-treated first at 475°C for 50 minutes under one atmosphere, then at 420°C for 30 minutes under a reduced pressure of 100 Torr, thereby obtaining 100% mesophase pitch (softening point, 250°C) in a yield of 50% based on ⁇ -methylnaphthalene.
- the resulting mesophase pitch had an average molecular weight of 900, a H/C atomic ratio of 0.51, and an fa of 0.93, with the methylic and naphthenic carbon contents being 2% and 6%, respectively, of the total carbon atoms.
- This pitch could be spun into fibers at a take-up speed of 300 m/min and at 360°C but not at a higher take-up speed of 500 m/min.
- the pitch fibers obtained by spinning at a take-up speed of 300 m/min could not be stabilized by heating up to 270°C at a rate of 5°C/min.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Textile Engineering (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Working-Up Tar And Pitch (AREA)
- Inorganic Fibers (AREA)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP309482/89 | 1989-11-29 | ||
JP30948289 | 1989-11-29 | ||
JP272300/90 | 1990-10-12 | ||
JP27230090A JP2917486B2 (ja) | 1989-11-29 | 1990-10-12 | 炭素材料用メソフェースピッチ |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0430689A1 true EP0430689A1 (fr) | 1991-06-05 |
EP0430689B1 EP0430689B1 (fr) | 1994-04-06 |
Family
ID=26550133
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19900312978 Expired - Lifetime EP0430689B1 (fr) | 1989-11-29 | 1990-11-29 | Brai en phase méso pour la préparation d'objets en carbone |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0430689B1 (fr) |
DE (1) | DE69007941T2 (fr) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0575748A1 (fr) * | 1992-06-19 | 1993-12-29 | Mitsubishi Gas Chemical Company, Inc. | Grains auto-adhésifs carbonés et articles en carbone à densité élevée dérivés de ces grains |
US5372702A (en) * | 1991-04-23 | 1994-12-13 | Mitsubishi Gas Chemical Company, Inc. | Composition for use in the production of composite carbon materials, composition carbon material produced therefrom, and process for producing the same |
EP0693543A3 (fr) * | 1994-07-11 | 1997-08-20 | Mitsubishi Gas Chemical Co | Brai ayant une tendance reduite de fumer pendant le filage et procédé pour la production de ce brai |
EP0838515A2 (fr) * | 1996-09-06 | 1998-04-29 | Mitsubishi Gas Chemical Company, Inc. | Procédé de fabrication de brai isotrope, de fibres de carbone activés et de matériaux carbonés pour anodes de batterie secondaire non-aqueuse |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2164351A (en) * | 1984-09-14 | 1986-03-19 | Kureha Chemical Ind Co Ltd | Process for producing carbon fibers |
EP0318843A1 (fr) * | 1987-11-27 | 1989-06-07 | Mitsubishi Gas Chemical Company, Inc. | Brai en phase méso pour la préparation d'articles en carbone et procédé de préparation dudit brai |
-
1990
- 1990-11-29 EP EP19900312978 patent/EP0430689B1/fr not_active Expired - Lifetime
- 1990-11-29 DE DE1990607941 patent/DE69007941T2/de not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2164351A (en) * | 1984-09-14 | 1986-03-19 | Kureha Chemical Ind Co Ltd | Process for producing carbon fibers |
EP0318843A1 (fr) * | 1987-11-27 | 1989-06-07 | Mitsubishi Gas Chemical Company, Inc. | Brai en phase méso pour la préparation d'articles en carbone et procédé de préparation dudit brai |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5372702A (en) * | 1991-04-23 | 1994-12-13 | Mitsubishi Gas Chemical Company, Inc. | Composition for use in the production of composite carbon materials, composition carbon material produced therefrom, and process for producing the same |
EP0575748A1 (fr) * | 1992-06-19 | 1993-12-29 | Mitsubishi Gas Chemical Company, Inc. | Grains auto-adhésifs carbonés et articles en carbone à densité élevée dérivés de ces grains |
US5547654A (en) * | 1992-06-19 | 1996-08-20 | Mitsubishi Gas Chemical Co., Ltd. | Self-adhesive carbonaceous grains and high density carbon artifacts derived therefrom |
EP0693543A3 (fr) * | 1994-07-11 | 1997-08-20 | Mitsubishi Gas Chemical Co | Brai ayant une tendance reduite de fumer pendant le filage et procédé pour la production de ce brai |
EP0838515A2 (fr) * | 1996-09-06 | 1998-04-29 | Mitsubishi Gas Chemical Company, Inc. | Procédé de fabrication de brai isotrope, de fibres de carbone activés et de matériaux carbonés pour anodes de batterie secondaire non-aqueuse |
EP0838515A3 (fr) * | 1996-09-06 | 1999-01-20 | Mitsubishi Gas Chemical Company, Inc. | Procédé de fabrication de brai isotrope, de fibres de carbone activés et de matériaux carbonés pour anodes de batterie secondaire non-aqueuse |
US5944980A (en) * | 1996-09-06 | 1999-08-31 | Mitsubishi Gas Chemical Company Co., Inc. | Method for producing isotropic pitch, activated carbon fibers and carbon materials for non-aqueous secondary battery anodes |
Also Published As
Publication number | Publication date |
---|---|
EP0430689B1 (fr) | 1994-04-06 |
DE69007941D1 (de) | 1994-05-11 |
DE69007941T2 (de) | 1994-08-11 |
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