JPH08217434A - Production of flaky graphite fine powder - Google Patents
Production of flaky graphite fine powderInfo
- Publication number
- JPH08217434A JPH08217434A JP7047803A JP4780395A JPH08217434A JP H08217434 A JPH08217434 A JP H08217434A JP 7047803 A JP7047803 A JP 7047803A JP 4780395 A JP4780395 A JP 4780395A JP H08217434 A JPH08217434 A JP H08217434A
- Authority
- JP
- Japan
- Prior art keywords
- graphite
- fine powder
- dispersion medium
- expanded graphite
- slurry
- 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.)
- Pending
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、薄片状黒鉛微粉末の製
造方法に関し、更に詳しくは導電材、電極材、潤滑剤等
の高機能性黒鉛材料として広範囲に利用し得る高アスペ
クト比の薄片状黒鉛微粉末の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing flaky graphite fine powder, and more particularly to a flaky graphite having a high aspect ratio which can be widely used as a highly functional graphite material such as a conductive material, an electrode material and a lubricant. The present invention relates to a method for producing fine graphite powder.
【０００２】[0002]
【従来の技術】黒鉛材料は導電性、潤滑性、耐食性、耐
熱性等の優れた特性を有しており、広範な分野で通常、
単独あるいは複合材として使用されている。とりわけ、
電極材や導電材として用いられるとき、黒鉛は、より高
いアスペクト比を持つ微粉体であることが望まれる。即
ち、より薄くかつ最大粒子径のより小さなものが望まれ
てきた。2. Description of the Related Art Graphite materials have excellent properties such as conductivity, lubricity, corrosion resistance, and heat resistance, and are generally used in a wide range of fields.
Used alone or as a composite. Above all,
When used as an electrode material or a conductive material, graphite is desired to be a fine powder having a higher aspect ratio. That is, thinner and smaller maximum particle size has been desired.
【０００３】元来、黒鉛は層状に剥離しやすい結晶構造
を有している。従って、黒鉛を粉砕すると厚み方向とそ
れに垂直な方向の大きさに異方性を生ずる。即ち、１よ
り大きいアスペクト比を有する粉末が得られる。しか
し、乾式粉砕法では黒鉛粉末の最大粒子径が小さくなる
に伴い、黒鉛粉末のアスペクト比が低下し、黒鉛粉末は
球に近くなる。従って、所望する薄片状黒鉛微粉末が得
られないという欠点があった。また、乾式で磨砕するこ
とにより黒鉛を微粉化すると、黒鉛の層間歪みが著しく
増大し、導電性、潤滑性等の黒鉛の特徴的な物性が損な
われる。Originally, graphite has a crystal structure that is easily separated in layers. Therefore, crushing graphite causes anisotropy in the size in the thickness direction and the size in the direction perpendicular thereto. That is, a powder having an aspect ratio greater than 1 is obtained. However, in the dry grinding method, as the maximum particle size of the graphite powder becomes smaller, the aspect ratio of the graphite powder decreases and the graphite powder becomes closer to a sphere. Therefore, there is a drawback that the desired flaky graphite fine powder cannot be obtained. Further, when the graphite is pulverized by dry grinding, interlayer strain of the graphite is remarkably increased, and characteristic properties of the graphite such as conductivity and lubricity are impaired.
【０００４】このような理由から、これまでに提案され
た黒鉛の薄片化、又は微粉化はおおむね湿式で行われて
いる。とりわけ、黒鉛を硫酸と硝酸の混酸で処理して得
られる黒鉛と硫酸の層間化合物、あるいは黒鉛を硫酸中
で電気的に酸化して得られる黒鉛と硫酸の層間化合物等
を加熱膨張させて得られる膨張黒鉛の広がった層間を利
用して、黒鉛を薄片化、又は微粉化する方法が有効であ
り、これまでにいくつかの方法が提案されている。For these reasons, the graphite exfoliation and pulverization that have been proposed so far are generally performed by a wet method. In particular, it is obtained by heating and expanding an intercalation compound of graphite and sulfuric acid obtained by treating graphite with a mixed acid of sulfuric acid and nitric acid, or an intercalation compound of graphite and sulfuric acid obtained by electrically oxidizing graphite in sulfuric acid. A method of thinning or pulverizing graphite using the expanded layers of expanded graphite is effective, and several methods have been proposed so far.
【０００５】特開昭６１−１２７６１２号公報には、膨
張黒鉛の空隙内に液体を充填した状態又は該液体を凍結
した状態で粉砕することを特徴とする導電性黒鉛材料の
製造方法が開示されている。この方法によれば、粉砕時
に嵩高い膨張黒鉛の飛散や層間の押し潰れ等を防ぐこと
はできるが、数時間の粉砕が必要であり、また凍結させ
る場合には充填した液体を凍結する装置等が必要である
など工業的な製造方法としては問題がある。Japanese Unexamined Patent Publication (Kokai) No. 61-127612 discloses a method for producing a conductive graphite material, which is characterized in that the expanded graphite is crushed in a state of being filled with a liquid or in a frozen state of the liquid. ing. According to this method, it is possible to prevent the bulky expansive graphite from scattering and crushing between layers during pulverization, but it is necessary to pulverize for several hours, and in the case of freezing, a device that freezes the filled liquid, etc. However, there is a problem as an industrial manufacturing method.
【０００６】特開平２‐１５３８１０号公報には、膨張
黒鉛を液体中に分散させ、この液体中で超音波を作用さ
せて、粒径が小さく、かつ高アスペクト比の均一な葉片
状黒鉛粉末を得る方法が開示されている。この方法で
は、超音波粉砕時間が１０分間〜６時間必要であり、ま
た液体中の黒鉛濃度が低いなどの問題点がある。該方法
では、粉砕時に黒鉛面方向にほとんど外力が加えられな
いため、薄片状黒鉛微粒子の結晶格子定数は原料黒鉛の
それとほぼ等しい。しかし、粒子の外周部の歪に起因す
る嵩高い粒子であり、その嵩比重は０．０２〜０．０６
程度と著しく小さいという欠点がある。In Japanese Patent Laid-Open No. 153810/1990, expanded graphite is dispersed in a liquid and ultrasonic waves are applied in the liquid to make uniform flake graphite powder having a small particle size and a high aspect ratio. Is disclosed. In this method, ultrasonic pulverization time is required for 10 minutes to 6 hours, and there are problems that the concentration of graphite in the liquid is low. In this method, since an external force is hardly applied in the graphite surface direction during pulverization, the crystal lattice constant of the flake graphite fine particles is almost equal to that of the raw material graphite. However, the particles are bulky due to the strain of the outer periphery of the particles, and their bulk specific gravity is 0.02 to 0.06.
It has the drawback of being extremely small.
【０００７】特開平６−２５４４２２号公報には、黒鉛
または膨張黒鉛を液体中に分散させ、該液体中にて球状
もしくはロッド状のメディアを作用させて磨砕すること
を特徴とする高配向性黒鉛粉末の製造方法が開示されて
いる。しかしながら、この方法でも粉砕時間は６〜２０
時間必要であり、従来の湿式粉砕方法に比べて粉砕時間
の短縮化はなされていない。また、得られた高配向性黒
鉛粉末の粒度分布が広いという問題点がある。In Japanese Patent Laid-Open No. 6-254422, graphite or expanded graphite is dispersed in a liquid, and a spherical or rod-shaped medium is caused to act in the liquid to grind it, which is highly oriented. A method of making graphite powder is disclosed. However, even with this method, the grinding time is 6 to 20.
It takes time, and the grinding time is not shortened as compared with the conventional wet grinding method. Further, there is a problem that the particle size distribution of the obtained highly oriented graphite powder is wide.
【０００８】また、湿式においても、長時間の磨砕は乾
式の場合と同様に黒鉛の層間歪みを増大させ黒鉛の結晶
性を損ないやすい。Also in the wet method, long-time grinding tends to increase the interlayer strain of graphite and impair the crystallinity of graphite as in the dry method.
【０００９】[0009]
【発明が解決しようとする課題】本発明は、本来、天然
黒鉛が有する導電性、潤滑性、耐食性、耐熱性等の優れ
た特性を損なうことなく、マトリックス中への分散性、
ハンドリング性、配向性等に優れた薄片状黒鉛微粉末
を、極めて短時間の粉砕で製造し得る方法を提供する。DISCLOSURE OF THE INVENTION The present invention is originally intended to disperse in a matrix without impairing the excellent properties of natural graphite such as conductivity, lubricity, corrosion resistance, and heat resistance.
Provided is a method capable of producing a flaky graphite fine powder excellent in handleability, orientation, etc. by pulverizing for an extremely short time.
【００１０】[0010]
【課題を解決するための手段】本発明は、１μｍ以下の
平均厚さを有し、かつ１００μｍ以下の粒子径の粒子が
９５体積％以上であるところの薄片状黒鉛微粉末を製造
する方法であって、膨脹黒鉛を分散媒体に浸漬した後、
膨脹黒鉛と分散媒体の全量に対して２〜１０重量％の膨
脹黒鉛濃度で該膨張黒鉛を粗粉砕して黒鉛スラリーを
得、次に該スラリーを回転式円盤状砥石を有する摩砕機
で微粉砕することを特徴とする薄片状黒鉛微粉末の製造
方法である。The present invention is a method for producing a flaky graphite fine powder having an average thickness of 1 μm or less and 95% by volume or more of particles having a particle size of 100 μm or less. After immersing the expanded graphite in the dispersion medium,
The expanded graphite is coarsely pulverized at a concentration of the expanded graphite of 2 to 10% by weight with respect to the total amount of the expanded graphite and the dispersion medium to obtain a graphite slurry, and then the slurry is finely pulverized by a grinder having a rotary disk-shaped grindstone. And a method for producing flaky graphite fine powder.
【００１１】本発明によれば、従来の方法に比べて、粉
砕時間を数十分の１〜数千分の１程度に短縮し得るのみ
ならず、粒度分布の狭い薄片状黒鉛微粉末を、天然黒鉛
が本来有する結晶性を損なうことなく製造し得る。According to the present invention, as compared with the conventional method, not only the crushing time can be shortened to several tenths to several thousandths, but also flaky graphite fine powder having a narrow particle size distribution can be obtained. It can be produced without impairing the crystallinity of natural graphite.
【００１２】本発明の方法に従って得られた薄片状黒鉛
微粉末は、１μｍ以下、好ましくは０．５μｍ以下の平
均厚さを有し、かつ１００μｍ以下、好ましくは１〜８
０μｍの粒子径の粒子が９５体積％以上、好ましくは９
８体積％以上である。また、該薄片状黒鉛微粉末のアス
ペクト比は、好ましくは２〜５００、特に好ましくは１
０〜２００である。上記の厚さを超えると、あるいは上
記粒子径の粒子の量が上記下限未満では、マトリックス
中への分散性が悪く、かつ導電性、潤滑性、耐蝕性、耐
熱性等の効果を十分に発現できない。The flaky graphite fine powder obtained according to the method of the present invention has an average thickness of 1 μm or less, preferably 0.5 μm or less, and 100 μm or less, preferably 1-8.
95% by volume or more of particles having a particle diameter of 0 μm, preferably 9
It is at least 8% by volume. The aspect ratio of the flaky graphite fine powder is preferably 2 to 500, and particularly preferably 1
It is 0 to 200. When the thickness exceeds the above, or the amount of particles having the above particle size is less than the above lower limit, the dispersibility in the matrix is poor, and the effects such as conductivity, lubricity, corrosion resistance, and heat resistance are sufficiently expressed. Can not.
【００１３】また、該薄片状黒鉛微粉末は、原料黒鉛の
結晶性をほとんどそのまま維持していることが、エック
ス線回折法により確認された。即ち、該薄片状黒鉛微粉
末のＣ(002) 結晶格子定数は、好ましくは０．６７０〜
０．６７３ｎｍであり、極めて高い結晶性を維持してい
る。また、その嵩比重は、好ましくは０．２〜０．６で
あり、上記の超音波粉砕法（特開平２‐１５３８１０
号）により得られる葉片状黒鉛粉末の約１０倍と著しく
高い。更に、その粒度分布が狭い。Further, it was confirmed by X-ray diffraction that the flaky graphite fine powder maintained the crystallinity of the raw material graphite almost as it was. That is, the C (002) crystal lattice constant of the flaky graphite fine powder is preferably 0.670 to
It is 0.673 nm and maintains extremely high crystallinity. Further, its bulk specific gravity is preferably 0.2 to 0.6, and the above-mentioned ultrasonic pulverization method (JP-A-2-153810).
No.), about 10 times that of the flake graphite powder obtained. Furthermore, its particle size distribution is narrow.
【００１４】まず、本発明において使用される膨張黒鉛
及びその製造方法は公知であり、特に限定されるもので
はない。例えば、天然鱗片状黒鉛、キッシュ黒鉛、高結
晶性熱分解黒鉛等の黒鉛粒子を硫酸と硝酸の混酸で処理
する方法、又は硫酸中で電気化学的に黒鉛を酸化する方
法で得られる黒鉛‐硫酸の層間化合物、あるいは黒鉛‐
テトラヒドロフラン等の黒鉛‐有機化合物の層間化合物
を、外熱式又は内熱式炉で、あるいはレーザー加熱等に
より急速加熱処理して膨張化させる方法により製造した
ものを使用し得る。First, the expansive graphite used in the present invention and the method for producing the same are known and are not particularly limited. For example, graphite-sulfuric acid obtained by a method of treating graphite particles such as natural flake graphite, quiche graphite, highly crystalline pyrolytic graphite with a mixed acid of sulfuric acid and nitric acid, or a method of electrochemically oxidizing graphite in sulfuric acid. Intercalation compound, or graphite
A graphite-organic compound intercalation compound such as tetrahydrofuran prepared by an externally heated or internally heated furnace or by a method of expanding by rapid heating treatment such as laser heating may be used.
【００１５】使用される膨張黒鉛の嵩比重は、該膨張黒
鉛の製造方法、貯蔵あるいは輸送、取り扱い方法等によ
って異なるが、分散媒体による浸漬の容易さ、得られる
薄片状黒鉛微粉末に導電性、潤滑性を賦与し、かつ該微
粉末のマトリックス中への分散性を良好ならしめるため
には、好ましくは０．０１以下、特に好ましくは０．０
０８以下である。The bulk specific gravity of the expanded graphite to be used varies depending on the manufacturing method of the expanded graphite, storage or transportation, handling method, etc., but it is easy to immerse in the dispersion medium, and the obtained flaky graphite fine powder has conductivity, In order to impart lubricity and to improve the dispersibility of the fine powder in the matrix, it is preferably 0.01 or less, particularly preferably 0.0
It is 08 or less.
【００１６】該膨脹黒鉛粒子の粒度分布（各粒子の最大
径の分布）は、好ましくは０．５〜３０ｍｍ、特に好ま
しくは１〜２０ｍｍの範囲の粒子が、好ましくは９５重
量％以上である。意外なことに、上記下限未満の粒子が
増加すると、所定の粒子厚さ及び径を持つ薄片状黒鉛微
粒子が得られ難くなり好ましくない。The expanded graphite particles have a particle size distribution (distribution of the maximum diameter of each particle) of preferably 0.5 to 30 mm, particularly preferably 1 to 20 mm, preferably 95% by weight or more. Surprisingly, when the number of particles is less than the above lower limit, it becomes difficult to obtain flake graphite fine particles having a predetermined particle thickness and diameter, which is not preferable.
【００１７】本発明においては、上記膨脹黒鉛を圧縮
し、嵩比重を好ましくは０．０５〜０．０２、特に好ま
しくは０．０５〜０．０４にしたものも使用することが
できる。これにより、分散媒体による浸漬、及び粗粉砕
によるスラリー化を効率よく行うことができる。また、
嵩の減少により、分散媒体の使用量を低減することがで
き、このことは、粉砕機の負荷を減らすために極めて有
効である。上記の程度の圧密化は、得られる薄片状黒鉛
微粉末の厚さ及び粒子径が大きくなる等の弊害をもたら
すことはない。In the present invention, the expanded graphite may be compressed to have a bulk specific gravity of preferably 0.05 to 0.02, particularly preferably 0.05 to 0.04. As a result, it is possible to efficiently perform the dipping in the dispersion medium and the slurrying by the coarse pulverization. Also,
Due to the reduced bulk, the amount of dispersion medium used can be reduced, which is very effective for reducing the load on the crusher. The above degree of consolidation does not bring about such an adverse effect that the thickness and particle size of the obtained flaky graphite fine powder become large.
【００１８】膨張黒鉛はまず、分散媒体中に浸漬され
る。膨脹黒鉛の濃度は、浸漬が十分に達成されるもので
あればよいが、続く粗粉砕処理を考慮して、膨脹黒鉛と
分散媒体の全量に対して好ましくは２〜１０重量％、特
に好ましくは３〜５重量％である。上記下限未満では、
膨脹黒鉛の粉砕処理量が低下し、効率的でない。上記上
限を越えては、膨脹黒鉛の層間あるいは微細な亀裂中へ
の媒体の侵入が不十分となり、かつ媒体中での膨脹黒鉛
の分散性が悪化する。従って、膨脹黒鉛の圧着が生じ粉
砕物の粒子径が大きくなる等の悪影響を及ぼす。膨脹黒
鉛の分散媒体中への浸漬は、通常公知の方法に従って行
われる。浸漬時間及び温度は、下記に掲げる分散媒体の
種類によって異なるが、例えば、分散媒体として水を使
用した場合、浸漬時間は好ましくは０．５〜１２時間、
特に好ましくは２〜６時間である。浸漬時間が上記下限
未満では、膨脹黒鉛の層間あるいは微細な亀裂中への媒
体の侵入が不十分となり、上記上限を越えても、著しい
効果の増加は認められない。また、浸漬温度は好ましく
は室温〜８０℃である。浸漬温度が上記下限未満では、
膨脹黒鉛の層間あるいは微細な亀裂中への媒体の侵入が
不十分となり、上記上限を越えては、著しい効果の増加
が認められないばかりか、媒体の蒸発が激しくなり好ま
しくない。また、膨脹黒鉛の層間あるいは微細な亀裂中
への媒体の侵入を促進するため、浸漬時に界面活性剤を
用いたり、超音波を使用したりすることもできる。The expanded graphite is first immersed in the dispersion medium. The concentration of the expanded graphite may be such that the immersion can be sufficiently achieved, but in consideration of the subsequent coarse pulverization treatment, it is preferably 2 to 10% by weight, and particularly preferably, the total amount of the expanded graphite and the dispersion medium. It is 3 to 5% by weight. Below the above lower limit,
The amount of crushed expanded graphite is reduced, which is not efficient. Above the upper limit, the penetration of the medium into the layers of the expanded graphite or into the fine cracks becomes insufficient, and the dispersibility of the expanded graphite in the medium deteriorates. Therefore, the expanded graphite is pressure-bonded to cause a bad effect such that the particle size of the pulverized product is increased. Immersion of the expanded graphite in the dispersion medium is usually performed according to a known method. The immersion time and temperature vary depending on the type of the dispersion medium listed below. For example, when water is used as the dispersion medium, the immersion time is preferably 0.5 to 12 hours,
Particularly preferably, it is 2 to 6 hours. If the immersion time is less than the above lower limit, the penetration of the medium into the layers of the expanded graphite or into fine cracks will be insufficient, and if the above upper limit is exceeded, no significant increase in the effect will be observed. The immersion temperature is preferably room temperature to 80 ° C. If the immersion temperature is less than the above lower limit,
The penetration of the medium into the layers of the expanded graphite or into the fine cracks becomes insufficient, and if the above upper limit is exceeded, not only a remarkable increase in the effect is not observed, but also the evaporation of the medium becomes severe, which is not preferable. Further, in order to promote the penetration of the medium into the layers of the expanded graphite or into the fine cracks, a surfactant or ultrasonic waves can be used during the immersion.
【００１９】分散媒体としては、浸漬と黒鉛粒子の分散
に適したものが使用され、粘度、表面張力が小さく、か
つ膨張黒鉛との濡れ性がよいものが好ましい。該分散媒
体として、例えば、水；アセトン、メチルエチルケトン
等のケトン類；メタノール、エタノール、プロパノー
ル、ブタノール等のアルコール類；又はベンゼン、トル
エン等の芳香族化合物等が挙げられ、上記媒体の単独又
は二種以上の混合物のいずれであってもよい。上記の分
散媒体中、好ましくは水が用いられる。As the dispersion medium, one suitable for immersion and dispersion of graphite particles is used, and one having a low viscosity and a small surface tension and a good wettability with expanded graphite is preferable. Examples of the dispersion medium include water; ketones such as acetone and methyl ethyl ketone; alcohols such as methanol, ethanol, propanol, butanol; and aromatic compounds such as benzene and toluene. The above media may be used alone or in combination. It may be any of the above mixtures. Water is preferably used in the above dispersion medium.
【００２０】上記浸漬後、次いで粗粉砕が実施される。
該粗粉砕は、膨脹黒鉛と分散媒体の全量に対して２〜１
０重量％、好ましくは３〜５重量％の膨脹黒鉛濃度で行
われる。該粗粉砕により、膨脹黒鉛は２ｍｍ以下の粒子
径の粒子が好ましくは９５重量％以上、特に好ましくは
９８重量％以上とされる。２ｍｍ以下の粒子径の粒子の
量が上記下限未満では、黒鉛粒子の沈降が激しく、流動
性の高い状態でハンドリングできず好ましくない。After the above immersion, coarse crushing is then carried out.
The coarse pulverization is performed in the amount of 2-1 with respect to the total amount of the expanded graphite and the dispersion medium.
It is carried out at an expanded graphite concentration of 0% by weight, preferably 3-5% by weight. By the coarse pulverization, the expanded graphite is preferably 95% by weight or more, and particularly preferably 98% by weight or more of particles having a particle diameter of 2 mm or less. If the amount of particles having a particle size of 2 mm or less is less than the above lower limit, the graphite particles are strongly sedimented and cannot be handled in a highly fluid state, which is not preferable.
【００２１】使用する粗粉砕機に特に制限はなく、通常
公知のものを使用し得る。好ましくは有翼のカッター型
粉砕機例えば愛工舎製作所製２５Ｓ型カッターミキサー
等、あるいは脱気可能な混合攪拌機、例えばダルトン社
製２５ＡＭＶ‐ｒｒ型等が使用され、短時間で粗粉砕並
びに媒体中への分散を達成し得る。所要時間は、好まし
くは約３０秒間〜３分間である。The coarse crusher used is not particularly limited, and a commonly known one can be used. Preferably, a winged cutter type crusher such as 25S type cutter mixer manufactured by Aikosha Seisakusho Co., Ltd. or a deaerating mixing stirrer such as 25 AMV-rr type manufactured by Dalton Co. is used, and coarse crushing and transfer to a medium in a short time Dispersion can be achieved. The required time is preferably about 30 seconds to 3 minutes.
【００２２】このように予め粗粉砕することにより、膨
張黒鉛から上記所定粒度の均一なスラリーを製造するこ
とができ、流動性の高いスラリー状態で微粉砕工程での
ハンドリングを行うことができる。従って、微粉砕後に
所定粒度の薄片状黒鉛微粉末を得ることができる。By thus preliminarily coarsely pulverizing, it is possible to produce a uniform slurry having the above-mentioned predetermined particle size from the expanded graphite, and it is possible to carry out handling in the fine pulverizing step in a slurry state having high fluidity. Therefore, it is possible to obtain flaky graphite fine powder having a predetermined particle size after fine pulverization.
【００２３】次いで、黒鉛スラリーは、回転式円盤状砥
石を有する摩砕機により微粉砕される。好ましくは１対
の回転式円盤状砥石を有する摩砕機が用いられる。分散
媒体中への浸漬により、スラリー中の黒鉛の層間もしく
は黒鉛の微細な亀裂の中には分散媒体が存在する。その
結果、膨張黒鉛に外力が加えられても黒鉛面同士が圧着
して膨張黒鉛が団粒化したり板状化することはない。従
って、微粉砕に付されるスラリー中に存在する分散媒体
は、該スラリーがハンドリングができる程度に残されて
いれば充分である。従って、膨脹黒鉛を粗粉砕して黒鉛
スラリーが得られた後、浸漬及び粗粉砕に必要とされた
過剰な分散媒体は、例えば、遠心分離機、フィルタープ
レス又は濾過等の公知の分離方法で除去又は回収するこ
とができる。分散媒体除去後の黒鉛の濃度は、好ましく
は１０〜６０重量％、特に好ましくは２０〜３０重量％
である。該濃度とすることにより、著しく微粉砕の効率
を高め、極めて短時間内に微粉砕することが可能とな
り、微粉時の負荷を大幅に低減することができる。上記
の回転式円盤状砥石は、例えばアルミナ、シリコンカー
バイド、ボロンナイトライド等のセラミックス材料、又
は金属にこれらのセラミックス材料あるいはダイアモン
ド等を溶射やコーティングしたり張り合わせた物、又は
ステンレス鋼、ハステロイ鋼等の耐磨耗性の高い金属、
又はタングステンカーバイド、チタンカーバイド等の超
硬金属等で作られていることが好ましい。また、該砥石
にはスラリーの送り溝があることが望ましい。更に、該
砥石の表面を好ましくは１６〜２４０番程度（ＪＩＳ
Ｒ ６００１）、特に好ましくは３２〜２４０番の凹凸
を有する梨地仕様とすることも迅速な粉砕に有効であ
る。該砥石のクリアランスは砥石が完全に接触した状態
から数ｍｍまでの間に設定できるが、５〜１００μｍと
することが好ましい。該砥石の回転数は任意に変化させ
ることができ、５００〜２０００ｒｐｍが好ましい。該
摩砕機による粉砕時間（砥石間での滞留時間）は、好ま
しくは１〜６０秒、特に好ましくは５〜４０秒である。
上記下限未満では十分に微粉砕することができず、上記
上限を越えると、極微小な粒子が多くなり、好ましくな
いことがある。上記粉砕時間の大半は、砥石の送り溝内
での滞留時間であり、砥石による真の粉砕時間は数秒に
過ぎないと考えられる。また、分散媒体として低沸点有
機溶剤を使用した場合には、該砥石の外側を冷却するこ
とが望ましい。該微粉砕に使用する摩砕機としては、例
えば、増幸産業株式会社製ＭＫＺＡ‐１０‐１５型マイ
クログラインダー等が挙げられる。Next, the graphite slurry is finely pulverized by a grinder having a rotary disk-shaped grindstone. Preferably, a grinder having a pair of rotary disk-shaped grindstones is used. Due to the immersion in the dispersion medium, the dispersion medium exists between the graphite layers in the slurry or in the fine cracks of the graphite. As a result, even if an external force is applied to the expanded graphite, the graphite surfaces are not pressed against each other and the expanded graphite does not aggregate or plate. Therefore, it is sufficient that the dispersion medium existing in the slurry to be finely pulverized is left to the extent that the slurry can be handled. Therefore, after the expanded graphite is coarsely pulverized to obtain a graphite slurry, excess dispersion medium required for the dipping and coarse pulverization is removed by a known separation method such as a centrifuge, a filter press or filtration. Or it can be collected. The concentration of graphite after removing the dispersion medium is preferably 10 to 60% by weight, particularly preferably 20 to 30% by weight.
Is. With this concentration, the efficiency of fine pulverization can be remarkably enhanced, and the fine pulverization can be performed within an extremely short time, and the load during fine pulverization can be significantly reduced. The above-mentioned rotary disk-shaped grindstone is, for example, alumina, silicon carbide, ceramic materials such as boron nitride, or those obtained by spraying or coating these ceramic materials or diamond on a metal, or stainless steel, Hastelloy steel, etc. A metal with high wear resistance,
Alternatively, it is preferably made of a superhard metal such as tungsten carbide or titanium carbide. Further, it is desirable that the grindstone has a feed groove for slurry. Furthermore, the surface of the grindstone is preferably about 16 to 240 (JIS
R 6001), particularly preferably a satin finish having irregularities of No. 32 to 240 is also effective for rapid crushing. The clearance of the grindstone can be set from a state in which the grindstone is in complete contact to several mm, and preferably 5 to 100 μm. The rotation speed of the grindstone can be arbitrarily changed, and is preferably 500 to 2000 rpm. The crushing time (residence time between grindstones) by the grinder is preferably 1 to 60 seconds, particularly preferably 5 to 40 seconds.
If it is less than the above lower limit, fine pulverization cannot be sufficiently carried out, and if it exceeds the above upper limit, there are many fine particles, which is not preferable. Most of the crushing time is the residence time of the grindstone in the feed groove, and the true crushing time by the grindstone is considered to be only a few seconds. When a low boiling point organic solvent is used as the dispersion medium, it is desirable to cool the outside of the grindstone. Examples of the attritor used for the fine pulverization include MKZA-10-15 type micro grinder manufactured by Masuko Sangyo Co., Ltd.
【００２４】上記摩砕機は、上記の膨脹黒鉛の粗粉砕に
も使用することができる。この際、３〜１４番の凹凸を
設けた砥石を使用することが好ましい。The attritor can also be used for coarsely pulverizing the expanded graphite. At this time, it is preferable to use a whetstone having irregularities Nos. 3 to 14.
【００２５】本発明の方法により製造された薄片状黒鉛
微粉末は、各種電池材料、導電ペースト、導電インキ、
導電塗料、セラミック発熱体、静電防止剤、電磁波シー
ルド材用の導電性付与材、固体潤滑剤として使用し得
る。The flaky graphite fine powder produced by the method of the present invention is used for various battery materials, conductive pastes, conductive inks,
It can be used as a conductive paint, a ceramic heating element, an antistatic agent, a conductivity-imparting material for an electromagnetic wave shielding material, and a solid lubricant.
【００２６】本明細書に記載した物性値は、以下の方法
で測定した値である。 ＜嵩比重＞５０ｍｌのガラス製メスシリンダーにサンプ
ルを入れ軽く１０回タッピングした後、サンプル容量を
測定し、サンプル重量をサンプル容量で除した値であ
る。 ＜Ｃ(002) 格子結晶定数＞東芝製Ｘ線回折装置ＸＣ−４
０Ｈを用い、Ｃｕ−Ｋα線をＮｉで単色化し、高純度シ
リコンを標準物質として、学振法でＣ(002) を測定して
求めた。 ＜厚さ＞日本電子製ＪＳＭ−５３００走査式電子顕微鏡
で試料形状を観察し、測定した。 ＜粒度分布＞島津製作所製レーザ回折式粒度分布測定装
置ＳＡＬＤ−１１００を用い、水を分散媒体として測定
した。The physical property values described in this specification are values measured by the following methods. <Bulk Specific Gravity> A sample is placed in a glass graduated cylinder of 50 ml, tapped lightly 10 times, the sample volume is measured, and the sample weight is divided by the sample volume. <C (002) lattice crystal constant> Toshiba X-ray diffractometer XC-4
The Cu-Kα ray was monochromated with Ni using 0H, and C (002) was measured by Gakushin method using high-purity silicon as a standard substance. <Thickness> The sample shape was observed and measured with a JEOL JSM-5300 scanning electron microscope. <Particle size distribution> Water was used as a dispersion medium for measurement using a laser diffraction particle size distribution analyzer SALD-1100 manufactured by Shimadzu Corporation.
【００２７】以下、本発明を実施例により更に詳細に説
明するが、本発明はこれら実施例により限定されるもの
ではない。Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
【００２８】[0028]
【００２９】[0029]
【実施例１】中国産鱗片状天然黒鉛（粒子径２５０〜５
００μｍ、灰分０．５重量％以下）５重量部を、硫酸９
重量部と硝酸１重量部から成る混酸で、１時間処理し黒
鉛−硫酸層間化合物を得た。次いで、これを水洗、乾燥
後、８００℃の電気炉で加熱膨張処理に付して、嵩比重
０．００４、粒子径（各粒子の最大径）が１〜１５ｍｍ
の範囲内の膨張黒鉛を得た。得られた膨張黒鉛３重量部
に対し水９７重量部を添加して、室温で２時間浸漬した
後、愛工舎製作所製２５Ｓ型カッターミキサーを用い
て、１分間膨張黒鉛の粗粉砕を行ない黒鉛スラリーを得
た。該スラリー中の膨張黒鉛粒子は、粒子径２ｍｍ以下
のものが９９．９重量％であった。続いて、増幸産業製
ＭＫＺＡ‐１０‐１５型マイクログラインダーを用い、
以下の条件で上記スラリーを微粉砕した。Example 1 Scale-like natural graphite from China (particle size 250-5
00 μm, ash content 0.5% by weight or less)
It was treated with a mixed acid consisting of 1 part by weight of nitric acid and 1 part by weight of nitric acid for 1 hour to obtain a graphite-sulfuric acid intercalation compound. Next, this is washed with water, dried, and then subjected to a heat expansion treatment in an electric furnace at 800 ° C. to obtain a bulk specific gravity of 0.004 and a particle diameter (maximum diameter of each particle) of 1 to 15 mm
Expanded graphite in the range of was obtained. After adding 97 parts by weight of water to 3 parts by weight of the obtained expanded graphite and immersing it at room temperature for 2 hours, the expanded graphite is coarsely pulverized for 1 minute using a 25S type cutter mixer manufactured by Aikosha Seisakusho Co., Ltd. to obtain a graphite slurry. Got The expanded graphite particles in the slurry contained 99.9% by weight of particles having a particle diameter of 2 mm or less. Then, using Masuza Sangyo MKZA-10-15 type micro grinder,
The above slurry was finely pulverized under the following conditions.
【００３０】微粉砕条件 グラインダー：ＭＫＧＳ８０# 、１対 グラインダー間クリアランス：６０μｍ グラインダー回転数：１２００ｒｐｍ スラリーのグラインダー内滞留時間：２０秒 上記微粉砕により得られた薄片状黒鉛微粉末の性状は、
下記の通りである。 Grinding conditions Grinder: MKGS80 # , clearance between 1 and grinder: 60 μm Grinder rotation speed: 1200 rpm Residence time of slurry in grinder: 20 seconds The properties of the flaky graphite fine powder obtained by the above pulverization are as follows:
It is as follows.
【００３１】薄片状黒鉛微粉末性状 嵩比重：０．４１ Ｃ(002) 格子結晶定数：０．６７２ｎｍ 最大厚み：０．８μｍ 平均厚み：０．１５μｍ 最大粒子径：８０μｍ 粒度分布は、表１に示す。Flake graphite fine powder Properties Bulk specific gravity: 0.41 C (002) Lattice Crystal constant: 0.672 nm Maximum thickness: 0.8 μm Average thickness: 0.15 μm Maximum particle size: 80 μm The particle size distribution is shown in Table 1. Show.
【００３２】[0032]
【表１】 表１から、得られた薄片状黒鉛微粉末は、１〜８０μｍ
の範囲の粒度を持つことが分かった。特開平６‐２５４
４２２号記載の方法により得られる黒鉛微粉末の粒子径
が０．１〜５００μｍであるのに比べて、その粒度分布
は著しく狭い。次に、該薄片状黒鉛微粉末１０重量部、
エポキシ樹脂（商標、Ｄ．Ｅ．Ｒ．３３１、ダウケミカ
ル社製）１００重量部及び硬化剤としてのトリエチレン
テトラミン１３重量部を混練後、成型圧１００ｋｇ／ｃ
ｍ2 で圧縮成形して１００×１２０×２ｍｍの成形体を
得、これから１０×１００×２ｍｍの試験片を切り出し
た。該試験片を用いて、薄片状黒鉛微粉末の樹脂中への
分散性と体積抵抗を測定し、導電性付与材としての性能
を評価した。また、比較のため、高導電性カーボンブラ
ック２種類［ケッチェンＥＣ（商標、ライオンアクゾ社
製）及び三菱化成３７５０（商標、三菱化成株式会社
製）］及び高導電性黒鉛１種類［ロンザＴ‐７０（商
標、ロンザ・ジャパン株式会社製）］について、上記と
同一条件で成型体を作成し、性能評価を実施した。以上
の結果を表２に示す。[Table 1] From Table 1, the obtained flaky graphite fine powder has a particle size of 1 to 80 μm.
It was found to have a granularity in the range of. JP-A-6-254
The fine graphite powder obtained by the method described in No. 422 has a particle size of 0.1 to 500 μm, but its particle size distribution is extremely narrow. Next, 10 parts by weight of the flaky graphite fine powder,
After kneading 100 parts by weight of an epoxy resin (trademark, DER 331, manufactured by Dow Chemical Co.) and 13 parts by weight of triethylenetetramine as a curing agent, a molding pressure of 100 kg / c
It was compression-molded with m 2 to obtain a molded body of 100 × 120 × 2 mm, from which a 10 × 100 × 2 mm test piece was cut out. Using the test piece, the dispersibility of the flaky graphite fine powder in the resin and the volume resistance were measured to evaluate the performance as a conductivity-imparting material. For comparison, two types of highly conductive carbon black [Ketjen EC (trademark, manufactured by Lion Akzo) and Mitsubishi Kasei 3750 (trademark, manufactured by Mitsubishi Kasei)] and one type of highly conductive graphite [Lonza T-70 (Trademark, manufactured by Lonza Japan Co., Ltd.)], a molded body was prepared under the same conditions as above, and performance evaluation was performed. Table 2 shows the above results.
【００３３】ここで、樹脂中への分散性は、表面及び切
断面を目視及び実体顕微鏡で観察し評価した。Here, the dispersibility in the resin was evaluated by visually observing the surface and the cut surface with a stereoscopic microscope.
【００３４】体積抵抗は、成形体の厚み方向と面方向の
両者について測定した。厚み方向については、試験片上
面及び下面に銀ペーストを塗布し、夫々の面に銅線を同
一のペーストで接着し、アドバンテスト社製マルチメー
ターＲ６５５１を用いて抵抗値を測定した。この抵抗値
に試料面積を乗じ、試料厚さで除した値を体積抵抗とし
た。面方向については、試験片の両端面から１０ｍｍ幅
で上、下及び側面に銀ペーストを塗布し、上面又は下面
の同一面上に夫々銅線を接着し、上記と同じく抵抗値を
測定して体積抵抗を算出した。The volume resistance was measured in both the thickness direction and the surface direction of the molded body. Regarding the thickness direction, silver paste was applied to the upper and lower surfaces of the test piece, copper wires were adhered to the respective surfaces with the same paste, and the resistance value was measured using an Advantest Multimeter R6551. The value obtained by multiplying this resistance value by the sample area and dividing by the sample thickness was taken as the volume resistance. Regarding the surface direction, silver paste is applied to the top, bottom and side surfaces of the test piece with a width of 10 mm from both end surfaces, copper wires are adhered to the same surface of the upper surface or the lower surface, and the resistance value is measured as above. The volume resistance was calculated.
【００３５】成型体密度は、試験片寸法をノギスで計測
して体積を求め、該試験片重量を該体積で除して算出し
た値である。The density of the molded body is a value calculated by measuring the size of the test piece with a caliper to determine the volume and dividing the weight of the test piece by the volume.
【００３６】[0036]
【表２】 以上のように、本発明の方法により得られた薄片状黒鉛
微粉末は、分散性が良好であり、また、比較のために用
いた高導電性カーボンブラック及び高導電性黒鉛と比べ
て、体積抵抗が著しく低く、導電性付与剤として良好な
性能を示した。[Table 2] As described above, the flaky graphite fine powder obtained by the method of the present invention has good dispersibility, and has a volume higher than that of the highly conductive carbon black and highly conductive graphite used for comparison. The resistance was remarkably low and it showed good performance as a conductivity-imparting agent.
【００３７】[0037]
【実施例２】実施例１で得たと同じ黒鉛スラリーを、連
続式遠心分離機で処理して水分を除去し、２５重量％の
黒鉛を含むスラリーとした。続いて、増幸産業製ＭＫＺ
Ａ‐１０‐１５型マイクログラインダーを用い、以下の
条件で上記スラリーを微粉砕した。Example 2 The same graphite slurry as obtained in Example 1 was treated with a continuous centrifuge to remove water, and a slurry containing 25% by weight of graphite was obtained. Next, MKZ made by Masuko Sangyo
Using an A-10-15 type micro grinder, the above slurry was finely pulverized under the following conditions.
【００３８】微粉砕条件 グラインダー：ＭＫＧＳ８０# 、１対 グラインダー間クリアランス：８０μｍ グラインダー回転数：１６００ｒｐｍ スラリーのグラインダー内滞留時間：３６秒 上記微粉砕により得られた薄片状黒鉛微粉末の性状は、
下記の通りである。 嵩比重：０．４４ Ｃ(002) 格子結晶定数：０．６７２ｎｍ 最大厚み：０．８μｍ 平均厚み：０．１５μｍ 最大粒子径：８０μｍ この様に、スラリー濃度を高めたものでも、実施例１と
ほぼ同じ厚さ及び粒子径の薄片状黒鉛微粉末を得ること
ができることが分かった。実施例２は、実施例１と比べ
て、単位時間当り約６．５倍の処理量を得ることができ
た。 Grinding conditions Grinder: MKGS80 # , 1-to-grinder clearance: 80 μm Grinder rotation speed: 1600 rpm Residence time of slurry in grinder: 36 seconds The properties of the flaky graphite fine powder obtained by the above pulverization are as follows:
It is as follows. Bulk Specific Gravity: 0.44 C (002) Lattice Crystal Constant: 0.672 nm Maximum Thickness: 0.8 μm Average Thickness: 0.15 μm Maximum Particle Diameter: 80 μm As described above, even if the slurry concentration was increased, It has been found that it is possible to obtain flaky graphite fine powder having approximately the same thickness and particle size. In Example 2, as compared with Example 1, it was possible to obtain a throughput of about 6.5 times per unit time.
【００３９】[0039]
【発明の効果】本発明は、本来、天然黒鉛が有する導電
性、潤滑性、耐食性、耐熱性等の優れた特性を損なうこ
となく、マトリックス中への分散性、ハンドリング性、
配向性等に優れた薄片状黒鉛微粉末を、極めて短時間の
粉砕で製造し得る方法を提供する。INDUSTRIAL APPLICABILITY The present invention inherently has a dispersibility in a matrix, a handling property, and the like without impairing the excellent properties of natural graphite such as conductivity, lubricity, corrosion resistance, and heat resistance.
Provided is a method capable of producing a flaky graphite fine powder having excellent orientation and the like by pulverizing for an extremely short time.
Claims (4)
０μｍ以下の粒子径の粒子が９５体積％以上であるとこ
ろの薄片状黒鉛微粉末を製造する方法であって、膨脹黒
鉛を分散媒体に浸漬した後、膨脹黒鉛と分散媒体の全量
に対して２〜１０重量％の膨脹黒鉛濃度で該膨張黒鉛を
粗粉砕して黒鉛スラリーを得、次に該スラリーを回転式
円盤状砥石を有する摩砕機で微粉砕することを特徴とす
る薄片状黒鉛微粉末の製造方法。1. An average thickness of 1 μm or less, and 10
A method for producing a flaky graphite fine powder in which particles having a particle diameter of 0 μm or less are 95% by volume or more, wherein the expanded graphite is immersed in a dispersion medium, and then the total amount of the expanded graphite and the dispersion medium is 2%. Flake graphite fine powder characterized in that the expanded graphite is coarsely pulverized at an expanded graphite concentration of 10 wt% to obtain a graphite slurry, and then the slurry is finely pulverized by a grinder having a rotary disk-shaped grindstone. Manufacturing method.
０５に圧密化されたものである請求項１記載の方法。2. The expanded graphite has a bulk specific gravity of 0.02 to 0.
The method of claim 1, wherein the method is consolidated to 05.
除去して１０〜６０重量％とした後、微粉砕する請求項
１又は２記載の方法。3. The method according to claim 1, wherein the concentration of the graphite slurry is 10 to 60% by weight after removing the dispersion medium, and then finely pulverized.
３のいずれか一つに記載の方法。4. The method according to claim 1, wherein the fine pulverization is performed within 1 minute.
The method according to any one of 3 above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7047803A JPH08217434A (en) | 1995-02-13 | 1995-02-13 | Production of flaky graphite fine powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7047803A JPH08217434A (en) | 1995-02-13 | 1995-02-13 | Production of flaky graphite fine powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08217434A true JPH08217434A (en) | 1996-08-27 |
Family
ID=12785538
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7047803A Pending JPH08217434A (en) | 1995-02-13 | 1995-02-13 | Production of flaky graphite fine powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08217434A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000002280A1 (en) * | 1998-07-06 | 2000-01-13 | Tdk Corporation | Electrode for nonaqueous electrolyte battery |
| JP2010525549A (en) * | 2007-04-23 | 2010-07-22 | アプライド・サイエンシズ・インコーポレーテッド | Method of depositing silicon on carbon material to form anode for lithium ion battery |
| JP2011513167A (en) * | 2008-02-28 | 2011-04-28 | ビーエーエスエフ ソシエタス・ヨーロピア | Graphite nanoplatelets and compositions |
| JP2014214341A (en) * | 2013-04-25 | 2014-11-17 | 日本カニゼン株式会社 | Electroless composite plating film, sliding movement part and rolling movement part formed with the same, and mold |
| JP2019094248A (en) * | 2017-11-28 | 2019-06-20 | 株式会社アカネ | Method of manufacturing thin layer graphite |
| JP2022536082A (en) * | 2019-06-05 | 2022-08-12 | キャボット コーポレイション | Densified reduced graphene oxide and manufacturing method |
-
1995
- 1995-02-13 JP JP7047803A patent/JPH08217434A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000002280A1 (en) * | 1998-07-06 | 2000-01-13 | Tdk Corporation | Electrode for nonaqueous electrolyte battery |
| US6824924B1 (en) | 1998-07-06 | 2004-11-30 | Tdk Corporation | Electrode for nonaqueous electrolyte battery |
| JP2010525549A (en) * | 2007-04-23 | 2010-07-22 | アプライド・サイエンシズ・インコーポレーテッド | Method of depositing silicon on carbon material to form anode for lithium ion battery |
| JP2011513167A (en) * | 2008-02-28 | 2011-04-28 | ビーエーエスエフ ソシエタス・ヨーロピア | Graphite nanoplatelets and compositions |
| JP2014214341A (en) * | 2013-04-25 | 2014-11-17 | 日本カニゼン株式会社 | Electroless composite plating film, sliding movement part and rolling movement part formed with the same, and mold |
| JP2019094248A (en) * | 2017-11-28 | 2019-06-20 | 株式会社アカネ | Method of manufacturing thin layer graphite |
| JP2022536082A (en) * | 2019-06-05 | 2022-08-12 | キャボット コーポレイション | Densified reduced graphene oxide and manufacturing method |
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