JP2009041127A - Method for producing vapor-grown carbon fiber, and vapor-grown carbon fiber - Google Patents
Method for producing vapor-grown carbon fiber, and vapor-grown carbon fiber Download PDFInfo
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 35
- 239000002134 carbon nanofiber Substances 0.000 title claims abstract description 25
- 239000003054 catalyst Substances 0.000 claims abstract description 61
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims abstract description 47
- 239000000835 fiber Substances 0.000 claims abstract description 20
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052751 metal Inorganic materials 0.000 claims abstract description 18
- 239000002184 metal Substances 0.000 claims abstract description 18
- 235000006408 oxalic acid Nutrition 0.000 claims abstract description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052742 iron Inorganic materials 0.000 claims abstract description 7
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 4
- 239000010941 cobalt Substances 0.000 claims abstract description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 26
- 239000002245 particle Substances 0.000 claims description 10
- 239000011777 magnesium Substances 0.000 claims description 9
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 7
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 claims description 7
- 239000011609 ammonium molybdate Substances 0.000 claims description 7
- 229940010552 ammonium molybdate Drugs 0.000 claims description 7
- 235000018660 ammonium molybdate Nutrition 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 239000011733 molybdenum Substances 0.000 claims description 7
- 150000001875 compounds Chemical class 0.000 claims description 5
- 150000002823 nitrates Chemical class 0.000 claims description 5
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 4
- 150000001242 acetic acid derivatives Chemical class 0.000 claims description 4
- 150000001805 chlorine compounds Chemical class 0.000 claims description 4
- 238000000975 co-precipitation Methods 0.000 claims description 4
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- ZKKLPDLKUGTPME-UHFFFAOYSA-N diazanium;bis(sulfanylidene)molybdenum;sulfanide Chemical compound [NH4+].[NH4+].[SH-].[SH-].S=[Mo]=S ZKKLPDLKUGTPME-UHFFFAOYSA-N 0.000 claims description 2
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 claims description 2
- VLAPMBHFAWRUQP-UHFFFAOYSA-L molybdic acid Chemical compound O[Mo](O)(=O)=O VLAPMBHFAWRUQP-UHFFFAOYSA-L 0.000 claims description 2
- 238000009826 distribution Methods 0.000 abstract description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 38
- 229920000049 Carbon (fiber) Polymers 0.000 description 36
- 239000004917 carbon fiber Substances 0.000 description 36
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 20
- 238000005087 graphitization Methods 0.000 description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 239000000243 solution Substances 0.000 description 10
- 239000007789 gas Substances 0.000 description 8
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 8
- 239000002243 precursor Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000001947 vapour-phase growth Methods 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 150000002736 metal compounds Chemical class 0.000 description 4
- 229910044991 metal oxide Inorganic materials 0.000 description 4
- 150000004706 metal oxides Chemical class 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 238000001069 Raman spectroscopy Methods 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- 238000004438 BET method Methods 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000001241 arc-discharge method Methods 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 238000001628 carbon nanotube synthesis method Methods 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 150000007942 carboxylates Chemical class 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- KTWOOEGAPBSYNW-UHFFFAOYSA-N ferrocene Chemical compound [Fe+2].C=1C=C[CH-]C=1.C=1C=C[CH-]C=1 KTWOOEGAPBSYNW-UHFFFAOYSA-N 0.000 description 1
- 238000007380 fibre production Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 150000002681 magnesium compounds Chemical class 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Abstract
Description
本発明は、気相成長炭素繊維の製造方法（以下、単に「製造方法」とも称する）および気相成長炭素繊維に関し、詳しくは、使用する触媒の改良に係る気相成長炭素繊維の製造方法および気相成長炭素繊維に関する。 The present invention relates to a method for producing a vapor-grown carbon fiber (hereinafter, also simply referred to as “manufacturing method”) and a vapor-grown carbon fiber, and more specifically, a method for producing a vapor-grown carbon fiber according to improvement of a catalyst used and It relates to vapor grown carbon fiber.
気相成長炭素繊維は、カーボンナノチューブ、カーボンナノファイバーとも呼ばれる直径がナノメートルオーダーの繊維状の炭素材料である。かかる気相成長炭素繊維は、炭化水素や一酸化炭素等の炭素を含むガスを原料とし、これら原料ガスを５００〜１５００℃程の高温下で触媒に接触させて熱分解させる気相成長法により製造され、触媒として使用する金属の種類や粒径等を選択することで、得られる繊維の形状を制御できることが知られている。 Vapor growth carbon fiber is a fibrous carbon material having a diameter of nanometer order called carbon nanotube or carbon nanofiber. Such vapor-grown carbon fibers are obtained by vapor-phase growth method in which a gas containing carbon such as hydrocarbon or carbon monoxide is used as a raw material, and these raw material gases are contacted with a catalyst at a high temperature of about 500 to 1500 ° C. and thermally decomposed. It is known that the shape of the resulting fiber can be controlled by selecting the type, particle size, etc. of the metal that is produced and used as the catalyst.
気相成長法で用いられる触媒は、例えば、溶液中で触媒金属と担体とを共沈させる共沈法により調製できることが知られている。例えば、特許文献１には、金属化合物、およびアルミニウムおよび／またはマグネシウム化合物からなる水溶液を形成し、カルボキシレート存在下でこれらを共沈させ、共沈物を処理して担持された原繊維形成触媒を製造する炭素原繊維形成触媒の製造方法が開示されており、前記金属としては、鉄若しくは鉄およびモリブデンが使用できることが開示されている。 It is known that the catalyst used in the vapor phase growth method can be prepared, for example, by a coprecipitation method in which a catalytic metal and a carrier are coprecipitated in a solution. For example, Patent Document 1 discloses a fibril-forming catalyst supported by forming an aqueous solution comprising a metal compound and an aluminum and / or magnesium compound, coprecipitating them in the presence of a carboxylate, and treating the coprecipitate. Is disclosed, and it is disclosed that iron or iron and molybdenum can be used as the metal.
また、特許文献２には、少なくとも水溶性VIII族金属化合物と、有機化合物とを含む混合物を焼成してなり、VIII族金属酸化物における非晶質VIII族金属酸化物が１０質量％以上で、且つ全金属酸化物における結晶質金属酸化物が８５質量％以下である気相成長法炭素繊維製造用触媒が開示されている。
カーボンナノチューブの合成法には、気相成長法以外にアーク放電法やレーザー蒸着法が存在するが、いずれもコストが高いという問題点がある。また、気相成長法においても、触媒に高価なフェロセン等を用いることが多いため、生産コストが高くなるという問題があった。さらに、低コストで一般的な触媒調製手法として含浸法が存在するが、含浸法で得られる触媒は表面積が狭いため、収率がよくないという難点があり、得られる気相成長炭素繊維も直径が太く、繊維径の分布も広くなってしまう。したがって、繊維径が細く繊維径の分布の狭い気相成長炭素繊維を、収率よく得るための技術の確立が求められていた。 The carbon nanotube synthesis methods include an arc discharge method and a laser vapor deposition method in addition to the vapor phase growth method, all of which have a problem of high cost. Also, in the vapor phase growth method, since expensive ferrocene or the like is often used for the catalyst, there is a problem that the production cost is increased. Furthermore, there is an impregnation method as a general catalyst preparation method at a low cost, but the catalyst obtained by the impregnation method has a problem that the yield is not good because the surface area is narrow, and the obtained vapor-grown carbon fiber also has a diameter. Is thick and the fiber diameter distribution becomes wide. Therefore, establishment of a technique for obtaining a vapor-grown carbon fiber having a narrow fiber diameter and a narrow fiber diameter distribution in a high yield has been demanded.
そこで、本発明の目的は、繊維径が細く繊維径の分布の狭い気相成長炭素繊維を、従来に比し高収率で得ることのできる気相成長炭素繊維の製造方法および気相成長炭素繊維を提供することにある。 Accordingly, an object of the present invention is to provide a vapor-grown carbon fiber production method and vapor-grown carbon, which can obtain a vapor-grown carbon fiber having a narrow fiber diameter and a narrow fiber diameter distribution in a higher yield than conventional ones. To provide fiber.
本発明者は、前記課題を解決するために鋭意検討した結果、気相成長法で用いる触媒を共沈法を用いて調製するにあたり、沈殿剤としてシュウ酸を用いることで、比較的高い収率で繊維径が細く繊維径の分布の狭い炭素繊維を得ることが可能となることを見出して、本発明を完成するに至った。 As a result of intensive studies to solve the above problems, the present inventor has obtained a relatively high yield by using oxalic acid as a precipitant when preparing a catalyst used in a vapor phase growth method using a coprecipitation method. The inventors have found that it is possible to obtain carbon fibers having a narrow fiber diameter and a narrow fiber diameter distribution, and have completed the present invention.
すなわち、本発明は、炭素を含むガスを触媒と接触させて気相成長炭素繊維を製造する方法において、前記触媒として、担体、活性金属種および助触媒を、シュウ酸を用いて共沈させて、得られるものを用いることを特徴とするものである。 That is, the present invention provides a method for producing a vapor-grown carbon fiber by bringing a gas containing carbon into contact with a catalyst, and co-precipitating a support, an active metal species and a promoter using oxalic acid as the catalyst. The obtained product is used.
また、本発明の気相成長炭素繊維は、上記本発明の製造方法により製造され、繊維径が５〜５０ｎｍであることを特徴とするものである。 The vapor grown carbon fiber of the present invention is produced by the production method of the present invention, and has a fiber diameter of 5 to 50 nm.
本発明によると、繊維径の細い気相成長炭素繊維を、従来に比し高収率で得ることのできる気相成長炭素繊維の製造方法および気相成長炭素繊維を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of vapor growth carbon fiber and vapor growth carbon fiber which can obtain the vapor growth carbon fiber with a small fiber diameter by a high yield compared with the former can be provided.
以下に本発明の実施の形態について具体的に説明する。
本発明の気相成長炭素繊維の製造方法は、炭素を含むガスを触媒と接触させて気相成長炭素繊維を製造する方法であり、前記触媒として、担体、活性金属種および助触媒を、シュウ酸を用いて共沈させて得られるものを用いることを特徴とするものである。
Embodiments of the present invention will be specifically described below.
The method for producing a vapor-grown carbon fiber of the present invention is a method for producing a vapor-grown carbon fiber by bringing a gas containing carbon into contact with a catalyst. As the catalyst, a support, an active metal species, and a promoter are used. What is obtained by coprecipitation with an acid is used.
本発明の製造方法において、活性金属種として鉄、ニッケル、コバルト、パラジウム等を用いることが好ましく、鉄、ニッケルまたはコバルトを用いることがさらに好ましい。 In the production method of the present invention, iron, nickel, cobalt, palladium or the like is preferably used as the active metal species, and iron, nickel or cobalt is more preferably used.
また、かかる活性金属種が、硝酸塩、酢酸塩、硫酸塩および塩化物塩から選ばれる少なくとも１種の化合物の形態であることが好ましく、硝酸塩であることがさらに好ましい。 The active metal species is preferably in the form of at least one compound selected from nitrates, acetates, sulfates and chlorides, and more preferably nitrates.
また、担体としては、マグネシウム、アルミニウム、シリカ、マンガン等を用いることが好ましく、マグネシウムを用いることがさらに好ましい。 As the carrier, magnesium, aluminum, silica, manganese or the like is preferably used, and magnesium is more preferably used.
さらに、かかる担体が、硝酸塩、酢酸塩、硫酸塩および塩化物塩から選ばれる少なくとも１種の化合物の形態であることが好ましく、硝酸マグネシウムであることがさらに好ましい。 Furthermore, the carrier is preferably in the form of at least one compound selected from nitrates, acetates, sulfates and chlorides, more preferably magnesium nitrate.
また、助触媒としては、モリブデン、イットリウム、タングステン等を用いることが好ましく、モリブデンを用いることがさらに好ましい。 As the cocatalyst, molybdenum, yttrium, tungsten, or the like is preferably used, and molybdenum is more preferably used.
さらに、かかる助触媒が、モリブデン酸、モリブデン酸アンモニウム、硫化モリブデン、モリブデンヘキサカルボニルまたはチオモリブデン酸アンモニウム等であることが好ましく、モリブデン酸アンモニウムであることがさらに好ましい。 Furthermore, the promoter is preferably molybdic acid, ammonium molybdate, molybdenum sulfide, molybdenum hexacarbonyl or ammonium thiomolybdate, and more preferably ammonium molybdate.
本発明の製造方法において、活性金属種と、担体および助触媒の合計との配合比率は、５：９５〜５０：５０であることが好ましく、７：９３〜３０：７０であることがさらに好ましい。活性金属種の配合比率が５：９５より小さいと十分な触媒性能が得られず炭素繊維の収率が悪くなる場合があり、５０：５０より大きいと均一な繊維径の炭素繊維とならず、好ましくない。 In the production method of the present invention, the blending ratio of the active metal species and the total of the support and the cocatalyst is preferably 5:95 to 50:50, more preferably 7:93 to 30:70. . When the blending ratio of the active metal species is less than 5:95, sufficient catalyst performance may not be obtained and the carbon fiber yield may be deteriorated, and when it is greater than 50:50, the carbon fiber does not have a uniform fiber diameter. It is not preferable.
本発明の製造方法において、シュウ酸のモル数が、活性金属種、担体および助触媒の合計モル数に対して、０．８〜２．０倍量であることが好ましく、１．０〜１．５倍量であることがさらに好ましい。このシュウ酸のモル数が０．８倍量より小さいと触媒が共沈しない場合があり、２．０倍量より大きいと微細で均一な触媒が得られない場合があり、好ましくない。 In the production method of the present invention, the number of moles of oxalic acid is preferably 0.8 to 2.0 times the total number of moles of active metal species, support and cocatalyst, 1.0 to 1 More preferably, the amount is 5 times. If the number of moles of oxalic acid is less than 0.8 times, the catalyst may not coprecipitate, and if it is more than 2.0 times, a fine and uniform catalyst may not be obtained.
また、本発明の製造方法において、触媒を、シュウ酸を用いて共沈させた後に、４００〜９００℃で１〜６時間焼成することが好ましく、５００〜７００℃で２〜５時間焼成することがさらに好ましい。焼成温度が４００℃より低いとシュウ酸塩の分解が不十分で炭素繊維の質が悪くなる場合があり、９００℃より高いと表面積が小さくなり炭素繊維の収率が悪くなる場合があり、好ましくない。また、焼成時間が１時間より短いとシュウ酸塩の分解が不十分で炭素繊維の質が悪くなる場合があり、６時間より長いと表面積が小さくなり炭素繊維の収率が悪くなる場合があり、好ましくない。 In the production method of the present invention, the catalyst is preferably co-precipitated with oxalic acid and then calcined at 400 to 900 ° C. for 1 to 6 hours, and calcined at 500 to 700 ° C. for 2 to 5 hours. Is more preferable. If the calcination temperature is lower than 400 ° C, the decomposition of the oxalate may be insufficient and the quality of the carbon fiber may be deteriorated. If it is higher than 900 ° C, the surface area may be decreased and the yield of the carbon fiber may be deteriorated. Absent. Also, if the firing time is shorter than 1 hour, the decomposition of the oxalate may be insufficient and the quality of the carbon fiber may be deteriorated. If it is longer than 6 hours, the surface area may be reduced and the yield of the carbon fiber may be deteriorated. It is not preferable.
さらに、本発明の製造方法において、触媒は、１０〜２００ｎｍの粒径で、かつ１５０〜１０００ｍ２／ｇの表面積であることが好ましく、３０〜１５０ｎｍの粒径で、かつ２００〜３００ｍ２／ｇの表面積であることがさらに好ましい。粒径が１０ｎｍより小さいと作業性が悪化する場合があり、２００ｎｍより大きいと触媒の効果が得られず炭素繊維の収率が悪くなる場合があり、好ましくない。また、表面積が１５０ｍ２／ｇより小さいと触媒の効果が得られず炭素繊維の収率が悪くなる場合があり、１０００ｍ２／ｇより大きいと作業性が悪化する場合があり、好ましくない。 Further, in the manufacturing method of the present invention, the catalyst is preferably in the particle size of 10 to 200 nm, and a surface area of 150~1000m 2 / g, with particle sizes of 30 to 150 nm, and 200 to 300 m 2 / g More preferably, the surface area is as follows. When the particle size is smaller than 10 nm, workability may be deteriorated. When the particle size is larger than 200 nm, the effect of the catalyst cannot be obtained and the yield of the carbon fiber may be deteriorated. On the other hand, if the surface area is less than 150 m 2 / g, the effect of the catalyst cannot be obtained and the yield of the carbon fiber may be deteriorated, and if it is greater than 1000 m 2 / g, the workability may be deteriorated.
さらにまた、本発明の製造方法において、触媒を、４００〜８００℃で１０〜１２０分間還元処理することが好ましく、水素／窒素が５０ｍＬ／５０ｍＬ／ｍｉｎ〜１０００ｍＬ／１０００ｍＬ／ｍｉｎの気流中で処理することが好ましい。還元処理温度が４００℃より低いと十分に還元できず炭素繊維の収率が悪くなる場合があり、８００℃より高いと触媒が凝集して表面積が低下する場合があり、好ましくない。また、還元処理時間が１０分間より短いと十分に還元できず炭素繊維の収率が悪くなる場合があり、１２０分間より長いと作業コストがかかり、好ましくない。さらに、水素／窒素が５０ｍＬ／５０ｍＬ／ｍｉｎより少ない気流中で処理すると十分な処理ができず、水素／窒素が１０００ｍＬ／１０００ｍＬ／ｍｉｎより多い気流中で処理すると触媒にＨ２が接触する時間が短くなり十分な処理ができない場合があり、好ましくない。 Furthermore, in the production method of the present invention, the catalyst is preferably subjected to a reduction treatment at 400 to 800 ° C. for 10 to 120 minutes, and the hydrogen / nitrogen is treated in an air stream of 50 mL / 50 mL / min to 1000 mL / 1000 mL / min. It is preferable. If the reduction treatment temperature is lower than 400 ° C., the reduction cannot be sufficiently performed and the yield of the carbon fiber may be deteriorated. If the temperature is higher than 800 ° C., the catalyst may be aggregated and the surface area may be reduced. Further, if the reduction treatment time is shorter than 10 minutes, the reduction cannot be sufficiently performed and the carbon fiber yield may be deteriorated. Furthermore, if the hydrogen / nitrogen treatment is performed in an air stream with less than 50 mL / 50 mL / min, sufficient treatment cannot be performed, and if the hydrogen / nitrogen is treated in an air stream with more than 1000 mL / 1000 mL / min, the time for H 2 to contact the catalyst is reached. This is not preferable because it may be shortened and sufficient processing may not be possible.
さらにまた、本発明の製造方法において、ガスと触媒の接触は、７００〜９００℃で０．２５〜２時間であることが好ましく、８００〜９００℃で０．５〜１．５時間であることがさらに好ましい。接触温度が７００℃より低いと触媒の効果が不十分で良好な炭素繊維を得ることができない場合があり、９００℃より高いとメタンが熱分解して触媒と接触する前に炭素となる場合があり、好ましくない。また、接触時間が０．２５時間より短いと触媒の効果が不十分で良好な炭素繊維を得ることができない場合があり、２時間より長いと触媒が失活し活性を示さず反応が進行しない場合があり、好ましくない。 Furthermore, in the production method of the present invention, the contact between the gas and the catalyst is preferably 700 to 900 ° C. for 0.25 to 2 hours, and 800 to 900 ° C. for 0.5 to 1.5 hours. Is more preferable. If the contact temperature is lower than 700 ° C, the effect of the catalyst may be insufficient and good carbon fibers may not be obtained. If the contact temperature is higher than 900 ° C, methane may be pyrolyzed to become carbon before contacting the catalyst. Yes, not preferred. Further, if the contact time is shorter than 0.25 hours, the effect of the catalyst may be insufficient and a good carbon fiber may not be obtained. If the contact time is longer than 2 hours, the catalyst is deactivated and does not exhibit activity and the reaction does not proceed. In some cases, it is not preferable.
本発明の製造方法において、ガスとしては炭素を含むガスであれば特に限定されず、例えば、メタン、エチレン、アセチレン等の炭化水素や、一酸化炭素、アルコール等が挙げられ、好ましくは、窒素／メタンとの混合ガスである。また、ガスの組成がＮ２／ＣＨ４＝１／１〜１／１０であり、この流量が触媒０．５ｇあたり１５０ｍＬ／ｍｉｎ〜１０００ｍＬ／ｍｉｎであることが、好ましい。 In the production method of the present invention, the gas is not particularly limited as long as it contains carbon, and examples thereof include hydrocarbons such as methane, ethylene, and acetylene, carbon monoxide, alcohols, and the like. It is a mixed gas with methane. The gas composition is preferably N 2 / CH 4 = 1/1 to 1/10, and the flow rate is preferably 150 mL / min to 1000 mL / min per 0.5 g of the catalyst.
また、本発明の気相成長炭素繊維は、上記本発明の製造方法により製造され、繊維径が５〜５０ｎｍであることを特徴とするものである。繊維径が５ｎｍより小さく合成することは物理的に難しく、５０ｎｍより大きいと炭素繊維の導電性等の物性が悪くなり、好ましくない。 The vapor grown carbon fiber of the present invention is produced by the production method of the present invention, and has a fiber diameter of 5 to 50 nm. It is physically difficult to synthesize the fiber diameter smaller than 5 nm, and when it is larger than 50 nm, the physical properties such as the conductivity of the carbon fiber deteriorate, which is not preferable.
次に、本発明を実施例により更に詳しく説明する。本発明は、この例によって限定されるものではない。 Next, the present invention will be described in more detail with reference to examples. The present invention is not limited by this example.
実施例１
触媒の調製
硝酸鉄（関東化学株式会社製）、硝酸マグネシウム（関東化学株式会社製）およびモリブデン酸アンモニウム（関東化学株式会社製）を、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：７：８３）の割合で秤量し、それぞれの前駆体のモル数に対して１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、活性金属化合物溶液を調製した。Ｆｅ＋Ｍｏ＋Ｍｇの合計モル数に対して１．２倍量のシュウ酸を１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、シュウ酸溶液を調製した。活性金属化合物溶液とシュウ酸溶液を混合し、鉄、マグネシウムおよびモリブデンをシュウ酸により同時に沈殿させた。遠心分離（２０００ｒｐｍ、１５分間）した後、上澄み液を廃棄して、９０％エタノールを加えて沈殿溶液を８０℃で４時間真空乾燥し、前駆体を作製した。得られた前駆体を５５０℃で４時間焼成して触媒とした。得られた触媒を図１に示す。この触媒は、粒径１００〜１５０ｎｍでＢＥＴ表面積が２５０ｍ２／ｇであった。
Example 1
Preparation of catalyst Iron nitrate (manufactured by Kanto Chemical Co., Inc.), magnesium nitrate (manufactured by Kanto Chemical Co., Ltd.) and ammonium molybdate (manufactured by Kanto Chemical Co., Ltd.) are in a weight ratio (Fe: Mo: Mg = 10: 7: 83). ) And was dissolved in 90% ethanol so as to be 1 mol / L with respect to the number of moles of each precursor to prepare an active metal compound solution. An oxalic acid solution was prepared by dissolving oxalic acid in an amount of 1.2 times the total number of moles of Fe + Mo + Mg in 90% ethanol to 1 mol / L. The active metal compound solution and the oxalic acid solution were mixed, and iron, magnesium and molybdenum were simultaneously precipitated with oxalic acid. After centrifugation (2000 rpm, 15 minutes), the supernatant was discarded, 90% ethanol was added, and the precipitate solution was vacuum-dried at 80 ° C. for 4 hours to prepare a precursor. The obtained precursor was calcined at 550 ° C. for 4 hours to obtain a catalyst. The obtained catalyst is shown in FIG. This catalyst had a particle size of 100 to 150 nm and a BET surface area of 250 m 2 / g.
粒径測定
粒径は、株式会社日立ハイテクノロジーズ社製のＳＥＭ Ｓ−５０００を用いて、ＳＥＭ観察で測定した。
Particle size measurement The particle size was measured by SEM observation using SEM S-5000 manufactured by Hitachi High-Technologies Corporation.
ＢＥＴ表面積測定
ＢＥＴ表面積は、ユアサアイオニクス株式会社製のＡｕｔｏＳｏｒｂ−１により測定した。
BET surface area measurement The BET surface area was measured by AutoSorb-1 manufactured by Yuasa Ionics.
前処理工程
得られた触媒を横型流通式反応炉中の５０ｍｇ石英ボードの上に配置し、水素／窒素＝１５０ｍＬ／１５０ｍＬ／ｍｉｎの気流中で６５０℃、２０分間還元処理した。
Pretreatment step The obtained catalyst was placed on a 50 mg quartz board in a horizontal flow reactor and subjected to reduction treatment at 650 ° C. for 20 minutes in a stream of hydrogen / nitrogen = 150 mL / 150 mL / min.
反応工程
前処理後の触媒を８００℃まで昇温し、水素をメタンに切り替え、窒素／メタン＝１５０ｍＬ／１５０ｍＬ／ｍｉｎで３０分間反応させた。反応後、生成した炭素繊維を取り出し、重さを秤量し、収量を算出した。収量は生成した炭素繊維から予め仕込んだ触媒の重量を引き、触媒中に含まれる活性金属の量で割ることにより触媒１ｇ当りの炭素繊維生成量として計算した。得られた炭素繊維を図２に示す。この炭素繊維は、繊維径１０〜３０ｎｍであった。また、収量およびグラファイト化度の結果を表１に示す。
Reaction Step The catalyst after the pretreatment was heated to 800 ° C., hydrogen was switched to methane, and the reaction was performed at nitrogen / methane = 150 mL / 150 mL / min for 30 minutes. After the reaction, the produced carbon fiber was taken out, weighed, and the yield was calculated. The yield was calculated as the amount of carbon fiber produced per gram of catalyst by subtracting the weight of the catalyst charged in advance from the produced carbon fiber and dividing by the amount of active metal contained in the catalyst. The obtained carbon fiber is shown in FIG. This carbon fiber had a fiber diameter of 10 to 30 nm. The results of yield and graphitization degree are shown in Table 1.
グラファイト化度（ラマン）測定
Ｎｉｃｏｌｅ Ａ Ｉｍｅｇａ ＸＲ（サーモフィシャーサイエンティフィック株式会社製）を使用して測定した。グラファイト化度とは、ラマンバンドのＧ（グラファイト）バンド（１５８０ｃｍ−１）とＤバンド（１３６０ｃｍ−１）のピーク比で、これによりカーボン表面のグラファイト化度が分かる。Ｇ／Ｄが高いほどグラファイト化度が高く、熱伝導性および電気伝導性が良好である。
Graphitization degree (Raman) measurement It measured using Nicole A Image XR (Thermo Fisher Scientific Co., Ltd. product). The graphitization degree, the peak ratio of the Raman band G (graphite) band (1580 cm -1) and D-band (1360 cm -1), thereby degree of graphitization of the carbon surface can be seen. The higher the G / D, the higher the degree of graphitization, and the better the thermal conductivity and electrical conductivity.
実施例２
実施例１の触媒調製における硝酸鉄を硝酸ニッケル（関東化学株式会社製）に変更した以外は実施例１と同様の方法により、炭素繊維を生成した。収量およびグラファイト化度の結果を表１に示す。
Example 2
Carbon fibers were produced in the same manner as in Example 1 except that the iron nitrate in the catalyst preparation of Example 1 was changed to nickel nitrate (manufactured by Kanto Chemical Co., Inc.). The results of yield and degree of graphitization are shown in Table 1.
実施例３
実施例１の触媒調製における硝酸鉄を硝酸コバルト（関東化学株式会社製）に変更した以外は実施例１と同様の方法により、炭素繊維を生成した。収量およびグラファイト化度の結果を表１に示す。
Example 3
Carbon fibers were produced in the same manner as in Example 1 except that the iron nitrate in the catalyst preparation of Example 1 was changed to cobalt nitrate (manufactured by Kanto Chemical Co., Inc.). The results of yield and degree of graphitization are shown in Table 1.
比較例１（含浸法）
触媒の調製
酸化マグネシウム（関東化学株式会社製）の粉末に、硝酸鉄およびモリブデン酸アンモニウムを溶解した９０％エタノールを添加して、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：７：８３）の割合の１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、エタノール溶液を調製した。得られたエタノール溶液を８０℃で４時間真空乾燥し、前駆体を作製した。得られた前駆体を５５０℃で４時間焼成して触媒とした。得られた触媒を図３に示す。この触媒は、粒径３００〜５００ｎｍでＢＥＴ表面積が７１ｍ２／ｇであった。
Comparative Example 1 (impregnation method)
Preparation of catalyst To a powder of magnesium oxide (manufactured by Kanto Chemical Co., Inc.), 90% ethanol in which iron nitrate and ammonium molybdate were dissolved was added, and in a weight ratio (Fe: Mo: Mg = 10: 7: 83) An ethanol solution was prepared by dissolving in 90% ethanol so that the ratio was 1 mol / L. The obtained ethanol solution was vacuum-dried at 80 ° C. for 4 hours to prepare a precursor. The obtained precursor was calcined at 550 ° C. for 4 hours to obtain a catalyst. The obtained catalyst is shown in FIG. This catalyst had a particle size of 300 to 500 nm and a BET surface area of 71 m 2 / g.
実施例１と同様の前処理工程および反応工程により、炭素繊維を生成した。得られた炭素繊維を図４に示す。この炭素繊維は、繊維径４０〜６０ｎｍであった。また、収量およびグラファイト化度の結果を表１に示す。 Carbon fibers were produced by the same pretreatment process and reaction process as in Example 1. The obtained carbon fiber is shown in FIG. This carbon fiber had a fiber diameter of 40 to 60 nm. The results of yield and graphitization degree are shown in Table 1.
比較例２（アンモニア沈殿法）
触媒の調製
硝酸鉄、硝酸マグネシウムおよびモリブデン酸アンモニウムを、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：７：８３）の割合で秤量し、９０％エタノールに溶解してエタノール溶液を調製した。沈殿物が形成されるまでアンモニアを滴下した。遠心分離（２０００ｒｐｍ、１５分間）した後、上澄み液を廃棄して、９０％エタノールを加えて沈殿溶液を８０℃で４時間真空乾燥し、前駆体を作製した。得られた前駆体を５５０℃で４時間焼成して触媒とした。
Comparative Example 2 (Ammonia precipitation method)
Preparation of Catalyst Iron nitrate, magnesium nitrate and ammonium molybdate were weighed in a weight ratio (Fe: Mo: Mg = 10: 7: 83) and dissolved in 90% ethanol to prepare an ethanol solution. Ammonia was added dropwise until a precipitate formed. After centrifugation (2000 rpm, 15 minutes), the supernatant was discarded, 90% ethanol was added, and the precipitate solution was vacuum-dried at 80 ° C. for 4 hours to prepare a precursor. The obtained precursor was calcined at 550 ° C. for 4 hours to obtain a catalyst.
実施例１と同様の前処理工程および反応工程により、炭素繊維を生成した。収量およびグラファイト化度の結果を表１に示す。 Carbon fibers were produced by the same pretreatment process and reaction process as in Example 1. The results of yield and degree of graphitization are shown in Table 1.
比較例３
比較例１の触媒調製における硝酸鉄を硝酸ニッケルに変更した以外は比較例１と同様の方法により、炭素繊維を生成した。収量およびグラファイト化度の結果を表１に示す。
Comparative Example 3
Carbon fibers were produced in the same manner as in Comparative Example 1 except that the iron nitrate in the catalyst preparation of Comparative Example 1 was changed to nickel nitrate. The results of yield and degree of graphitization are shown in Table 1.
図１および図２から、実施例のシュウ酸法により、従来の含浸法と比較して微細で表面積の大きい触媒が得られることが分かり、図３および図４から、実施例のシュウ酸法により、従来の含浸法と比較して微細な炭素繊維が得られることが分かる。また、表１より、本発明の方法により、高収率で炭素繊維が得られることが分かる。 1 and 2, it can be seen that the oxalic acid method of the example gives a finer and larger surface area catalyst than the conventional impregnation method. From FIGS. 3 and 4, the oxalic acid method of the example It can be seen that fine carbon fibers can be obtained as compared with the conventional impregnation method. Moreover, it can be seen from Table 1 that carbon fiber can be obtained with high yield by the method of the present invention.
実施例４、５
硝酸鉄、硝酸マグネシウムおよびモリブデン酸アンモニウムを、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：１０：８０）の割合で秤量し、前駆体を表２記載の温度で焼成した以外は実施例１と同様の方法により、炭素繊維を生成した。収量およびグラファイト化度の結果を表３に示す。
Examples 4 and 5
Example 1 except that iron nitrate, magnesium nitrate and ammonium molybdate were weighed in a weight ratio of (Fe: Mo: Mg = 10: 10: 80) and the precursor was calcined at the temperature described in Table 2. Carbon fibers were produced by the same method. The results of yield and degree of graphitization are shown in Table 3.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017006888A (en) * | 2015-06-26 | 2017-01-12 | デンカ株式会社 | Catalyst for producing carbon nanofiber, method for producing carbon nanofiber, and carbon nanofiber |
| CN115477300A (en) * | 2022-08-03 | 2022-12-16 | 烯湾科城(广州)新材料有限公司 | Carbon nano tube, fluidized bed preparation process thereof and conductive agent |
-
2007
- 2007-08-07 JP JP2007205863A patent/JP2009041127A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017006888A (en) * | 2015-06-26 | 2017-01-12 | デンカ株式会社 | Catalyst for producing carbon nanofiber, method for producing carbon nanofiber, and carbon nanofiber |
| CN115477300A (en) * | 2022-08-03 | 2022-12-16 | 烯湾科城(广州)新材料有限公司 | Carbon nano tube, fluidized bed preparation process thereof and conductive agent |
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