JPH05213611A - Treatment of graphitic powder and graphite powder for making them hydrophilic - Google Patents
Treatment of graphitic powder and graphite powder for making them hydrophilicInfo
- Publication number
- JPH05213611A JPH05213611A JP4224654A JP22465492A JPH05213611A JP H05213611 A JPH05213611 A JP H05213611A JP 4224654 A JP4224654 A JP 4224654A JP 22465492 A JP22465492 A JP 22465492A JP H05213611 A JPH05213611 A JP H05213611A
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- Japan
- Prior art keywords
- graphite
- particles
- powder
- graphite particles
- hydrophilic
- 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.)
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Abstract
Description
【０００１】[0001]
【産業上の利用技術】本発明は、水に対する分散性の良
好な黒鉛質粉体および黒鉛粉体の親水化処理方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite powder having good dispersibility in water and a method for hydrophilizing graphite powder.
【０００２】[0002]
【従来の技術】天然黒鉛や人造黒鉛などの黒鉛材料は、
優れた耐熱性、耐食性、耐熱衝撃性、熱伝導性、電気伝
導性など多くの好ましい特徴を有することから、工業上
広範な分野でそのままあるいは複合体として使用されて
いる。2. Description of the Related Art Graphite materials such as natural graphite and artificial graphite are
Since it has many preferable features such as excellent heat resistance, corrosion resistance, thermal shock resistance, thermal conductivity, and electrical conductivity, it is used as it is or as a composite in a wide range of industrial fields.
【０００３】黒鉛を複合したファインセラミックスや耐
火物を製造する場合には、黒鉛粉体および黒鉛粉体と複
合する金属酸化物、金属炭化物、金属窒化物、金属硼化
物などの粉体との混合粉体に、水や有機溶媒などの分散
媒、界面活性剤などの分散剤および結合剤などを加え、
混合あるいは混練して低粘性の泥漿あるいは坏土とし
て、鋳込み成形、プレス成形、押出し成形などにより成
形体を得ることが行なわれている。In the case of producing fine ceramics or refractory material containing graphite, a mixture of graphite powder and powder of metal oxide, metal carbide, metal nitride, metal boride, etc. which is combined with graphite powder is mixed. To the powder, add a dispersion medium such as water or organic solvent, a dispersant such as a surfactant and a binder,
BACKGROUND ART Mixing or kneading to obtain a low-viscosity sludge or kneaded clay is performed by a cast molding, a press molding, an extrusion molding, etc.
【０００４】しかし、黒鉛粉体はその固有の特性として
親水性に欠けており、使いやすい水を分散媒として用い
る場合、分散剤を用いても良好な分散性が得られないと
いう問題がある。However, graphite powder lacks hydrophilicity as an inherent property, and there is a problem that good dispersibility cannot be obtained even when a dispersant is used when water that is easy to use is used as the dispersion medium.
【０００５】一方、分散媒として有機溶媒を用いること
は、作業環境上あるいは火災防止の観点から好ましくな
く、水を分散媒として使用するのが最も好まれる。On the other hand, it is not preferable to use an organic solvent as the dispersion medium from the viewpoint of work environment or fire prevention, and it is most preferable to use water as the dispersion medium.
【０００６】黒鉛粉体である天然黒鉛の粉体や人造黒鉛
の粉体の粒子表面は、炭素原子の六角網目構造により特
徴づけられ、−ＯＨ、−ＣＯＯＨなどの官能基がわずか
に存在しているのみで、複合する相手の金属酸化物、金
属炭化物、金属窒化物、金属硼化物などの粉体と比べる
と、分散媒として水を使用したときの界面におけるゼー
タ（ζ）電位の絶対値が小さいことによって分散性が乏
しく、その結果として密度の大きい成形体が得難く、ひ
いては最終製品の特性としての耐酸化性、耐食性、耐熱
衝撃性、熱伝導性、電気伝導性などが期待するレベルよ
り低くなってしまうという問題がある。The particle surface of natural graphite powder or artificial graphite powder, which is a graphite powder, is characterized by a hexagonal network structure of carbon atoms, and a small number of functional groups such as --OH and --COOH exist. However, the absolute value of the zeta (ζ) potential at the interface when water is used as the dispersion medium is greater than that of the powder of the complexing metal oxide, metal carbide, metal nitride, metal boride, etc. Since it is small, the dispersibility is poor, and as a result, it is difficult to obtain a molded product having a high density, and as a result, the oxidation resistance, corrosion resistance, thermal shock resistance, thermal conductivity, electrical conductivity, etc., which are the properties of the final product, are higher than expected levels. There is a problem of becoming low.
【０００７】この問題点を回避する工夫として、強酸処
理法、ＣＶＤ法、湿式ゾルゲル法、ポリマーコート法な
どの表面処理方法が検討されているが、いずれの方法に
ついても水に対する満足な分散性はいまだ得られていな
い。As a method for avoiding this problem, surface treatment methods such as a strong acid treatment method, a CVD method, a wet sol-gel method, a polymer coating method and the like have been investigated, but any of them has satisfactory dispersibility in water. Not obtained yet.
【０００８】すなわち、強酸処理法では黒鉛粉体を濃硫
酸、濃硝酸、フッ酸などに浸し、常温ないし100 ℃程度
の温度で反応させて黒鉛粒子の表面を親水性に変えるこ
とができるが、酸成分が黒鉛の結晶層内に侵入する層間
化合物を形成して黒鉛粒子が膨張したり、処理後の粒子
の表面や層間に残留している酸成分の除去が困難であ
り、次の工程で坏土や泥漿に含まれる水分中にこの酸成
分が溶出し、ｐＨが変動して分散状態を不安定にするた
め、やはり密度の高い成形体が得られないという欠点が
ある。That is, in the strong acid treatment method, the graphite powder can be immersed in concentrated sulfuric acid, concentrated nitric acid, hydrofluoric acid, etc. and reacted at room temperature to about 100 ° C. to change the surface of the graphite particles to hydrophilic. An acid compound forms an intercalation compound that penetrates into the crystal layer of graphite to expand the graphite particles, and it is difficult to remove the acid component remaining on the surface of the particles or the interlayer after the treatment. This acid component is dissolved in the water contained in the kneaded clay or the slurry, and the pH is changed to make the dispersion state unstable, so that there is also a drawback that a compact having a high density cannot be obtained.
【０００９】ＣＶＤ処理としては、たとえば黒鉛粒子の
表面とＳｉＯやＢ2 Ｏ3 などのガス成分とを１０００℃
以上の高温下で反応させ、その表面にＳｉＣやＢ4 Ｃな
どの薄膜を生成せしめることが行なわれており、ゼータ
電位の絶対値が大きい粉体が得られているが、同時に黒
鉛粒子の表面が酸化されて密度の低い荒れた表面組織が
できて耐酸化性が低下するなどの問題がある。As the CVD treatment, for example, the surface of graphite particles and a gas component such as SiO or B2 O3 are heated to 1000.degree.
It has been performed that the reaction is performed at the above high temperature to form a thin film of SiC, B4 C, etc. on the surface, and powder having a large absolute value of zeta potential is obtained. There is a problem in that a rough surface structure having a low density is formed by being oxidized and the oxidation resistance is lowered.
【００１０】他に、ガス相から固体を析出させ、表面に
荒れた組織を形成しないハライドＣＶＤ法などもある
が、原料ガスが高価であったり、排ガス処理が必要であ
ったりして、付加価値の大きくない大量に使用される耐
火物用原料を処理するには適していない方法しか見当た
らない。There is also a halide CVD method in which a solid is precipitated from the gas phase and a rough structure is not formed on the surface, but the raw material gas is expensive and the exhaust gas treatment is required, which results in added value. There are only unsuitable methods for treating refractory raw materials that are not used in large quantities and are used in large quantities.
【００１１】湿式ゾルゲル処理法では、たとえばシリコ
ンアルコキシド、アルミニウムアルコキシドなどを酸触
媒の存在下でアルコール水溶液と反応させて加水分解
し、ゾル溶液とした処理液を黒鉛粉体に含浸せしめ、乾
燥してゲル化し、黒鉛粒子の表面にＳｉＯ2 やＡｌ2 Ｏ
3 などを付着せしめることができるが、黒鉛粒子と処理
液との濡れ性が悪く、黒鉛粒子の表面と被覆層の間にミ
クロの気孔が形成されたり、被覆層そのものに気孔がで
きたりすることによって、黒鉛粒子の水に対する良好な
分散性が得られないとともに、この黒鉛質粉体（以下表
面処理された黒鉛粒子からなる粉体をを黒鉛質粉体とい
う。）を使用すると成形体の気孔率が大きくなるという
問題がある。In the wet sol-gel treatment method, for example, silicon alkoxide, aluminum alkoxide, etc. are hydrolyzed by reacting with an aqueous alcohol solution in the presence of an acid catalyst to impregnate the graphite powder with the treatment solution as a sol solution, followed by drying. Gelled and formed on the surface of graphite particles SiO2 and Al2 O
3 can be attached, but the wettability between the graphite particles and the treatment liquid is poor, and micropores may be formed between the surface of the graphite particles and the coating layer, or pores may be formed in the coating layer itself. As a result, good dispersibility of the graphite particles in water cannot be obtained, and when this graphite powder (hereinafter, the powder composed of the surface-treated graphite particles is referred to as graphite powder) is used, the pores of the molded body are There is a problem that the rate becomes large.
【００１２】また、特公平２−３３６６６に開示されて
いるようなポリマーコート法では、たとえばフェノール
樹脂、フラン樹脂、シリコーン樹脂などの溶液を黒鉛粉
末に含浸させて黒鉛粒子の表面に有機物の被覆層を形成
することができるが、湿式ゾルゲル処理法と同様の問題
があって、この黒鉛質粉体からは良好な特性を有する緻
密な成形体が得られないという問題がある。In the polymer coating method disclosed in Japanese Patent Publication No. 2-33666, for example, a graphite powder is impregnated with a solution of a phenol resin, a furan resin, a silicone resin or the like to coat the surface of the graphite particles with an organic coating layer. However, there is a problem similar to the wet sol-gel treatment method, and there is a problem that a dense compact having good characteristics cannot be obtained from this graphite powder.
【００１３】これら従来の処理方法でも、黒鉛粒子の表
面がより好ましい特性になるように改善することも可能
であるが、そのためには複雑なプロセスと制御が必要で
あって、黒鉛粉体の表面処理コストが高くなってしまう
という欠点がある。Even with these conventional treatment methods, it is possible to improve the surface of the graphite particles so as to have more preferable characteristics. However, this requires a complicated process and control, and the surface of the graphite powder is There is a drawback that the processing cost becomes high.
【００１４】最近の技術としては、特公平３−２００９
に固体粒子の表面処理方法の記載があり、その明細書の
説明には、０．１μｍ〜１００μｍの範囲にある粉体の
表面に、０．０１μｍ〜１０μｍの範囲にある粉体を固
着せしめるのに、機械的衝撃を用いる方法が有効であ
り、粉体の表面を改質する好ましい方法として、気流中
で衝撃処理する方法が提案されている。As a recent technique, Japanese Patent Publication No. 3-2009
Describes the method of surface treatment of solid particles, and in the description of the specification, the powder in the range of 0.01 μm to 10 μm is fixed to the surface of the powder in the range of 0.1 μm to 100 μm. In addition, a method using mechanical impact is effective, and a method of impact treatment in an air stream has been proposed as a preferable method for modifying the surface of powder.
【００１５】しかし、黒鉛粒子の表面改質が可能かどう
かについての記載がなく、特に耐火物の原料として多く
用いられ、特異な劈開を示す鱗片状の天然黒鉛原料の改
質に適用できるか否かについては全く不明である。However, there is no description as to whether or not surface modification of graphite particles is possible, and in particular, it is often used as a raw material for refractory materials and is applicable to the modification of scaly natural graphite raw material exhibiting unique cleavage. It is unknown at all.
【００１６】[0016]
【発明が解決しようとする課題】本発明の目的は、従来
技術の有していたこれらの欠点を解消し、簡便、かつ低
コストの処理方法により、水に対する優れた分散性を有
し、高密度の黒鉛複合成形体を容易に得ることができる
黒鉛質粉体と黒鉛粉体の親水化処理方法を提供しようと
するものである。SUMMARY OF THE INVENTION The object of the present invention is to solve these drawbacks of the prior art, to provide a simple and low-cost treatment method, which has excellent dispersibility in water and a high dispersibility. An object of the present invention is to provide a graphite powder capable of easily obtaining a graphite composite compact having a high density and a method for hydrophilizing the graphite powder.
【００１７】[0017]
【課題を解決するための手段】本発明は前述の課題を解
決するためになされたもので、本発明の黒鉛質粉体は、
黒鉛質粒子からなる粉体であって、黒鉛粒子の表面に、
黒鉛粒子より平均粒子径が小さく、かつ親水性を有する
小粒子が固着されていることを特徴とする。The present invention has been made to solve the above-mentioned problems, and the graphite powder of the present invention is
A powder composed of graphite particles, the surface of the graphite particles,
It is characterized in that small particles having an average particle size smaller than that of graphite particles and having hydrophilicity are fixed.
【００１８】本発明の黒鉛質粉体の好ましい態様では、
親水性を有する小粒子が、金属酸化物、金属炭化物、金
属窒化物、金属硼化物および金属の中から選ばれる一種
以上からなる。In a preferred embodiment of the graphite powder of the present invention,
The hydrophilic small particles are composed of one or more selected from metal oxides, metal carbides, metal nitrides, metal borides and metals.
【００１９】このような黒鉛質粉体は、たとえば黒鉛粒
子からなる粉体原料と、親水性を有する、黒鉛粒子より
も小さい平均粒子径の小粒子からなる粉体との混合粉体
を、高速気流中に投入し、粒子同志を衝突せしめ、ある
いは互いに付着している状態のものに機械的な衝撃を繰
り返し加える衝撃処理を行ない、親水性のある粒子を黒
鉛粒子の表面に固着せしめることにより得ることができ
る。Such a graphite powder is prepared by mixing a powder raw material composed of graphite particles and a powder composed of hydrophilic small particles having an average particle size smaller than the graphite particles at high speed. Obtained by throwing in an air stream and causing particles to collide with each other, or by repeatedly applying a mechanical shock to particles in a state where they are attached to each other to make hydrophilic particles adhere to the surface of graphite particles. be able to.
【００２０】黒鉛粉体に親水性小粒子の粉体を混合し、
衝撃処理を繰り返し行なうことによって、黒鉛粉体に親
水性を付与すると同時に、他の機能をも併せて保有する
黒鉛質粉体とすることが可能である。Mixing powder of hydrophilic small particles to graphite powder,
By repeatedly performing the impact treatment, it is possible to impart hydrophilicity to the graphite powder and at the same time provide a graphite powder having other functions.
【００２１】本発明の黒鉛質粉体の粉体原料としては、
天然黒鉛や電極屑などの人造黒鉛、高温で熱処理された
石油コークスやカーボンブラックなどが使用できる。As the powder raw material of the graphite powder of the present invention,
Artificial graphite such as natural graphite and electrode scrap, petroleum coke or carbon black heat-treated at high temperature can be used.
【００２２】黒鉛粉体の平均粒子径は０．１μｍ以下の
ものから１ｍｍ以上のものまで各種使用が可能である
が、好ましくは１μｍ以上、１ｍｍ以下のものを使用す
る。これは、１μｍ未満であると黒鉛材料に固有の好ま
しい特性が充分に得られず、１ｍｍより大きいと粒子の
衝撃処理による黒鉛粒子表面への親水性小粒子の固着効
率が低下し、黒鉛粒子の親水性粒子による良好な被覆が
できなくなるので好ましくない。Various types of graphite powder having an average particle size of 0.1 μm or less to 1 mm or more can be used, but preferably 1 μm or more and 1 mm or less are used. This is because when it is less than 1 μm, preferable characteristics peculiar to the graphite material are not sufficiently obtained, and when it is more than 1 mm, the adhesion efficiency of the hydrophilic small particles to the surface of the graphite particles due to the impact treatment of the particles is lowered, and It is not preferable because good coating with hydrophilic particles cannot be obtained.
【００２３】黒鉛粒子の表面に固着される親水性の粉体
としては、金属酸化物、金属炭化物、金属窒化物、金属
硼化物、金属などが有効であり、これらの中から一種以
上の粉体を、使用目的に応じて選んで用いるとよい。As the hydrophilic powder adhered to the surface of the graphite particles, metal oxides, metal carbides, metal nitrides, metal borides, metals, etc. are effective, and one or more powders are selected from these. May be selected and used according to the purpose of use.
【００２４】すなわち、泥漿、坏土などとして鋳込み成
形、押出し成形、プレス成形するときに、分散媒である
水（ｐＨなどの条件も含めて）に対するゼータ電位の絶
対値が大きく、良好な分散性を示す組み合わせ、さらに
は最終製品の使用目的に応じ、耐熱性、耐食性、耐熱衝
撃性、熱伝導性、電気伝導性、黒鉛粒子の酸化防止機能
などの特性を発現するのに適した粉体を選定するとよ
い。That is, when cast molding, extrusion molding, or press molding as slurry or kneaded clay, the absolute value of the zeta potential with respect to water (including conditions such as pH) as a dispersion medium is large, and good dispersibility is obtained. The powders suitable for exhibiting properties such as heat resistance, corrosion resistance, thermal shock resistance, thermal conductivity, electrical conductivity, and antioxidant function of graphite particles, depending on the intended use of the final product. Good to choose.
【００２５】黒鉛粒子の酸化防止機能を有するものとし
ては、小粒子の酸素親和力が黒鉛粒子より大きく、酸化
されて焼結体の通気性を低下せしめるものや、高温で溶
けてガラス相などを形成し黒鉛粒子を覆うような性質を
有するものなどが例として挙げられる。As the one having the function of preventing the oxidation of the graphite particles, the oxygen affinity of the small particles is larger than that of the graphite particles, and those which are oxidized to lower the air permeability of the sintered body, and those which are melted at a high temperature to form a glass phase, etc. An example thereof is one having a property of covering graphite particles.
【００２６】小粒子の平均粒子径は、黒鉛粒子の平均粒
子径の２０％以下、さらには１０％以下とするのが好ま
しく、これによって小粒子の表面エネルギーがより大き
くなり、黒鉛粒子への小粒子の固着性を高めることがで
きる。The average particle size of the small particles is preferably 20% or less, more preferably 10% or less of the average particle size of the graphite particles, whereby the surface energy of the small particles becomes larger and the average particle size of the graphite particles becomes smaller. The adherence of particles can be increased.
【００２７】小粒子の平均粒子径が黒鉛粒子より大きか
ったり、同等である場合には、黒鉛粒子に固着される親
水性粒子の割合が少なくなり、固着の強度が低下する
他、次に何らかの方法で成形体としたときにも、気孔率
の大きい、特性の劣る成形体しか得られない。When the average particle size of the small particles is larger than or equal to that of the graphite particles, the proportion of the hydrophilic particles fixed to the graphite particles is reduced, and the strength of the adhesion is reduced. Even when formed into a molded article, only a molded article having large porosity and poor characteristics can be obtained.
【００２８】本発明の親水化された黒鉛質粉体は、黒鉛
粒子より平均粒子径の小さい親水性の小粒子を黒鉛粒子
とともに、従来の機械的乾式粉砕装置に投入することに
よって得ることができるが、特に特公平３−２００９に
記載されているような装置を用い、高速気流中で粒子同
志を衝突せしめる、あるいは黒鉛粒子に親水性の小粒子
が付着した状態のものに衝撃を繰り返し加えるという衝
撃処理を行なうことによって能率良くかつ簡便に得るこ
とができる。The hydrophilized graphite powder of the present invention can be obtained by charging hydrophilic small particles having an average particle size smaller than that of the graphite particles together with the graphite particles into a conventional mechanical dry pulverizer. However, using a device such as that described in Japanese Examined Patent Publication No. 3-2009, the particles are made to collide with each other in a high-speed airflow, or a shock is repeatedly applied to a state in which small hydrophilic particles are attached to graphite particles. It is possible to obtain it efficiently and easily by performing the impact treatment.
【００２９】大抵の組み合わせの場合、黒鉛粒子は親水
性の小粒子より硬度が低いので、小粒子は黒鉛粒子表面
にめりこみ、小粒子の黒鉛粒子表面への固着を容易に行
なうことができ、親水性が小さい黒鉛粒子に良好な親水
性を付与することが容易にできる。In most combinations, the graphite particles have a hardness lower than that of the hydrophilic small particles, so that the small particles can sink into the surface of the graphite particles and easily adhere to the surfaces of the graphite particles. It is possible to easily impart good hydrophilicity to the graphite particles having low property.
【００３０】本発明の黒鉛質粉体は、たとえば次の方法
で簡便に得ることができる。先ず、あらかじめ決めた割
合の黒鉛粉体と親水性の小粒子の粉体を撹拌羽根を備え
たミキサー中で混合し、黒鉛粒子のまわりに小粒子が静
電気力などで付着し均等に分散された混合物とする。The graphite powder of the present invention can be easily obtained, for example, by the following method. First, a predetermined proportion of graphite powder and powder of hydrophilic small particles were mixed in a mixer equipped with a stirring blade, and the small particles adhered around the graphite particles due to electrostatic force and were uniformly dispersed. Let it be a mixture.
【００３１】次いでこの混合物を、たとえば奈良機械社
製の高速気流中衝撃処理を行なう装置などに投入して、
粉体の粒子に衝撃力、圧縮力、摩擦力、剪断力などの機
械的作用を繰り返し与え、黒鉛粒子がひどく破砕されな
いようにその強さを調整した状態で、小粒子を黒鉛粒子
の表面に固着せしめる。Next, this mixture is put into, for example, an apparatus for impact treatment in a high-speed air stream manufactured by Nara Machinery Co., Ltd.
Mechanical particles such as impact force, compressive force, frictional force, and shearing force are repeatedly applied to the particles of the powder, and the strength is adjusted so that the graphite particles are not severely crushed. Fix it firmly.
【００３２】このとき、黒鉛粒子は鱗片状のような特異
な形状をしていても、角が取れて球状あるいは楕球状に
近づくとともに、この黒鉛粒子の表面に親水性の小粒子
がめりこんだ状態で固着して被覆された状態となる。At this time, even if the graphite particles have a peculiar shape such as scale-like, the corners are removed and the particles approach a spherical shape or an elliptic shape, and small hydrophilic particles are embedded in the surface of the graphite particles. In this state, they are fixed and covered.
【００３３】黒鉛質粉体の黒鉛粒子の形状としては、鱗
片状や針状のようにアスペクト比の大きいものではな
く、さいころ状などのようにアスペクト比の小さいもの
である方が黒鉛粒子の破砕が起きにくく、小粒子の固着
が容易である。したがって、あらかじめなんらかの処理
を施したアスペクト比の小さい黒鉛粒子からなる黒鉛粉
体を使用することは好ましい方法である。As for the shape of the graphite particles of the graphite powder, the one having a smaller aspect ratio such as a dice shape is not crushed than the one having a large aspect ratio such as a scaly shape or a needle shape. Is less likely to occur, and small particles are easily fixed. Therefore, it is a preferable method to use a graphite powder made of graphite particles having a small aspect ratio which has been previously treated.
【００３４】本発明の黒鉛粉体の親水化処理方法では、
粉体粒子の衝撃処理の間に、黒鉛粒子がたとえアスペク
ト比の大きいものであっても、その角が取れ、アスペク
ト比を小さくする作用を同時に伴うので、小粒子の固着
性がよくなると同時に、充填性の良好な黒鉛質粉体が得
られるので都合がよい。In the method for hydrophilicizing graphite powder of the present invention,
During the impact treatment of the powder particles, even if the graphite particles have a large aspect ratio, the corners are removed, and at the same time, the action of reducing the aspect ratio is accompanied, so that the adhesion of the small particles is improved and at the same time, This is convenient because a graphite powder having a good filling property can be obtained.
【００３５】この衝撃処理の間の粉体の温度はせいぜい
１５０℃程度であり、黒鉛粒子や小粒子は化学的な変化
を受けない。この衝撃処理の間に小粒子の方はある程度
破砕されても固着性についてはとくに支障がない。The temperature of the powder during the impact treatment is about 150 ° C. at most, and the graphite particles and the small particles are not chemically changed. Even if the small particles are crushed to some extent during this impact treatment, there is no particular problem with the sticking property.
【００３６】また、黒鉛粉体の黒鉛粒子に表面亀裂や凹
凸がある場合には、小粒子が黒鉛粒子の亀裂や凹凸の部
分にめりこんで固着され、これによって最終的な成形体
の気孔率を小さくすることになり、ひいてはこれを原料
として製造する複合成形体を高温で使用する際、空気の
成形体内部への侵入が抑制され、黒鉛粒子の酸化が防止
されることになる。When the graphite particles of the graphite powder have surface cracks or irregularities, small particles are stuck and fixed in the cracks or irregularities of the graphite particles, which results in the porosity of the final molded body. Therefore, when the composite molded body produced from this as a raw material is used at high temperature, invasion of air into the molded body is suppressed, and oxidation of graphite particles is prevented.
【００３７】黒鉛粉体に衝撃処理を複数回行なう場合に
は、初めに固着する小粒子については親水性を備えてい
ることを重視する必要がなく、酸化防止機能や通気性低
減機能などを有する小粒子を先ず固着せしめ、最後に固
着する小粒子を親水性のある小粒子とすればよく、これ
によりさらに高機能の複合成形体を形成する黒鉛質粉体
を得ることができる。When the graphite powder is subjected to the impact treatment a plurality of times, it is not necessary to give importance to the hydrophilicity of the small particles that are fixed first, and it has an antioxidant function and a gas permeability reducing function. The small particles may be fixed first, and the small particles fixed last may be hydrophilic small particles, whereby a graphite powder for forming a more highly functional composite molded article can be obtained.
【００３８】また、二種以上の親水性の小粒子の混合粉
体を黒鉛粉体の黒鉛粒子に固着せしめる場合には、それ
ぞれの小粒子に異なる機能を担わせることが可能であ
る。When a mixed powder of two or more kinds of hydrophilic small particles is fixed to the graphite particles of the graphite powder, each small particle can have a different function.
【００３９】黒鉛粉体の黒鉛粒子に固着させる親水性の
小粒子の混合割合は、黒鉛粒子の表面を完全に被覆する
ためには大抵３０重量％以下でよく、好ましくは２０重
量％以下とする。The mixing ratio of the hydrophilic small particles fixed to the graphite particles of the graphite powder is usually 30% by weight or less, preferably 20% by weight or less, in order to completely cover the surface of the graphite particles. ..
【００４０】このようにして得られる本発明の黒鉛質粉
体は、水を分散媒として用い、界面活性剤などの分散剤
や結合剤などとともに混合、混練して粘性が小さく固体
成分の多い泥漿や、高密度の成形体の得られる坏土を得
ることができ、鋳込み成形、押出し成形、プレス成形な
どにより容易に緻密で、特性の優れた黒鉛の複合成形体
を得ることができる。The graphite powder of the present invention thus obtained uses water as a dispersion medium, and is mixed and kneaded with a dispersant such as a surfactant and a binder to prepare a slurry having a small viscosity and a large solid content. Alternatively, it is possible to obtain a kneaded material from which a high-density molded body can be obtained, and it is possible to easily obtain a dense graphite composite molded body having excellent characteristics by casting molding, extrusion molding, press molding, or the like.
【００４１】特に、天然の鱗片状黒鉛粉体を本発明の黒
鉛質粉体としたものは耐酸化性、耐食性、耐濡れ性、耐
熱衝撃性などに優れ、耐火物用原料として好ましいもの
である。また、本発明の黒鉛粉体の親水化処理方法は、
黒鉛粉体原料を比較的短時間で能率良く親水性の良好な
黒鉛質粉体に変えることができる方法であり、産業上の
利用価値が高いものである。In particular, the natural flake graphite powder used as the graphite powder of the present invention is excellent in oxidation resistance, corrosion resistance, wettability, thermal shock resistance, etc. and is preferable as a raw material for refractory materials. .. Further, the method for hydrophilicizing the graphite powder of the present invention,
This is a method that can change a graphite powder raw material into a graphite powder having good efficiency and good hydrophilicity in a relatively short time, and has high industrial utility value.
【００４２】[0042]
【実施例】次に、本発明を実施例に基づいて説明する
が、本発明はこれらの実施例によってなんら限定される
ものではない。EXAMPLES The present invention will now be described based on examples, but the present invention is not limited to these examples.
【００４３】高速気流中で粉体の粒子を衝撃処理する装
置として、奈良機械社製の衝撃処理装置（型式名ＮＨＳ
−３）を用いた。この装置の主要部は図１と図２に断面
図で示されている構成を有しており、図１は正面の断面
図で図２はその側面の断面図である。As an apparatus for impact-treating powder particles in a high-speed air stream, an impact-treatment apparatus (model name: NHS) manufactured by Nara Machinery Co., Ltd.
-3) was used. The main part of this device has the construction shown in cross-section in FIGS. 1 and 2, with FIG. 1 being a front cross-section and FIG. 2 being a side cross-section.
【００４４】図中１はケーシング、２は前方壁、３は後
方壁、４は回転板、５はブレード、６は回転軸、７は衝
撃室、８は衝撃壁、９は粉体出口弁、１０は粉体循環回
路管、１１は原料粉体導入弁、１２はホッパーである。In the figure, 1 is a casing, 2 is a front wall, 3 is a rear wall, 4 is a rotating plate, 5 is a blade, 6 is a rotating shaft, 7 is an impact chamber, 8 is an impact wall, 9 is a powder outlet valve, 10 is a powder circulation circuit tube, 11 is a raw material powder introduction valve, and 12 is a hopper.
【００４５】すなわちこの装置では、ホッパー１２に入
れられた原料粉体は、原料入口弁１１を開いてリング状
空間からなる衝撃室７内に導入される。衝撃室７中に
は、図示されていない電動機により駆動される回転軸６
に固定された回転板４と、回転板４に固定されたブレー
ド５があってともに高速で回転している。That is, in this apparatus, the raw material powder put in the hopper 12 is introduced into the impact chamber 7 having a ring-shaped space by opening the raw material inlet valve 11. In the impact chamber 7, there is a rotating shaft 6 driven by an electric motor (not shown).
There is a rotary plate 4 fixed to the rotary plate 4 and a blade 5 fixed to the rotary plate 4, and both rotate at high speed.
【００４６】ブレード５の回転エネルギーは、衝撃室７
内において高速気流のエネルギーに変換され、衝撃室７
に取りつけられた粉体循環回路管１０の閉じた流路を気
流が粉体を乗せて循環するようになっている。The rotational energy of the blade 5 is determined by the impact chamber 7
Inside the shock chamber 7
An air stream carries the powder and circulates through the closed flow path of the powder circulation circuit tube 10 attached to the.
【００４７】循環する黒鉛粒子と親水性の小粒子はこの
中で互に衝突したりする相互作用をし、高速で回転して
いるブレード５による衝撃力を受けることにより、圧縮
力、摩擦力、剪断力などの機械的作用を繰り返し受け
る。The circulating graphite particles and the hydrophilic small particles interact with each other so that they collide with each other and receive the impact force of the blade 5 rotating at a high speed, thereby compressing force, friction force, Repeatedly subjected to mechanical action such as shearing force.
【００４８】その結果、黒鉛粉体の黒鉛粒子は次第にそ
の角が取れて、アスペクト比の小さい球状あるいは楕球
状の粒子形状に近づくと同時に、黒鉛粒子の表面には親
水性のある小粒子が固着され、かつ被覆されることによ
って黒鉛粒子に親水性が付与される。As a result, the graphite particles of the graphite powder gradually get closer to a spherical shape or an ellipsoidal shape having a small aspect ratio, and at the same time, small hydrophilic particles adhere to the surface of the graphite particles. By being coated and coated, hydrophilicity is imparted to the graphite particles.
【００４９】この際ブレード５の回転速度は、黒鉛粉体
の黒鉛粒子が破砕されない速度に調整されている。所定
の時間衝撃処理を行なったのち表面が親水性の小粒子で
被覆された黒鉛粒子からなる黒鉛質粉体は、粉体出口弁
９を開いて取り出される。At this time, the rotation speed of the blade 5 is adjusted to a speed at which the graphite particles of the graphite powder are not crushed. After impact treatment for a predetermined time, the graphite powder composed of graphite particles whose surfaces are coated with hydrophilic small particles is taken out by opening the powder outlet valve 9.
【００５０】試験例 黒鉛粉体として、固定炭素分が９８％で粒子径１５０μ
ｍ以下で平均粒子径約５１μｍの鱗片状天然黒鉛粉体
と、固定炭素分が９９％で粒子径１５０μｍ以下で平均
粒子径約３２μｍの人造黒鉛の粉体を用い、親水性を有
する小粒子からなる粉体原料として黒鉛質粉体よりもゼ
ータ電位の絶対値が大きく、水への分散性に優れるアル
ミナ（平均粒子径約０．６μｍ）、シリカ（平均粒子径
約１μｍ）、炭化珪素（平均粒子径約５．４μｍ）、金
属アルミニウム（平均粒子径約１２μｍ）を単独あるい
は組み合わせて使用し、表１、表２に示す組み合わせと
条件で黒鉛粉体の親水化処理を行なった。Test Example As a graphite powder, the fixed carbon content was 98% and the particle size was 150 μm.
From the small particles having hydrophilicity, scaly natural graphite powder having an average particle size of 51 μm or less and an artificial graphite powder having a fixed carbon content of 99% and a particle size of 150 μm or less and an average particle size of 32 μm or less are used. , Which has a larger absolute value of zeta potential than graphite powder and is excellent in dispersibility in water (average particle size of about 0.6 μm), silica (average particle size of about 1 μm), silicon carbide (average The particle size was about 5.4 μm) and metallic aluminum (average particle size was about 12 μm) were used alone or in combination, and the graphite powder was hydrophilized under the combinations and conditions shown in Tables 1 and 2.
【００５１】すなわち、上述の高速気流中衝撃処理装置
にそれぞれの組み合わせの混合粉体を投入して衝撃処理
を行なった。高速気流中衝撃処理装置における回転板４
の外周速度は、１０〜１５０ｍ／秒の範囲で調節が可能
であるが、試験に供した黒鉛粉体の黒鉛粒子の場合に
は、破砕がほとんど起きないように７５ｍ／秒以下の外
周速度で衝撃処理を行なうことが必要であることが分か
った。That is, the mixed powders of the respective combinations were put into the above-described high-speed air current impact treatment device to perform impact treatment. Rotating plate 4 in high-speed air shock processing device
The outer peripheral speed of can be adjusted in the range of 10 to 150 m / sec. However, in the case of the graphite particles of the graphite powder used in the test, the outer peripheral speed is 75 m / sec or less so that crushing hardly occurs. It has been found necessary to carry out shock treatment.
【００５２】以下の試験では、黒鉛粒子の破砕が起きな
いことと、小粒子の固着が効果的に行なわれることを考
慮して、外周速度が６０ｍ／秒となるように回転軸６の
回転数を調整し、試験を行なった。また処理時間につい
ては、１〜２０分の範囲で変えることもできるが、短時
間であっても処理効果が充分得られる条件ということで
３分間に設定した。このようにして表面処理されたそれ
ぞれの黒鉛質粉体を以下の方法によって評価し、その結
果を表１と表２に併せて示した。なお、粉体の粒度分布
はレーザー回折式粒度分布計（マイクロトラック社製、
モデル７９９７）により測定し、積算体積が１／２の位
置の粒子径を平均粒子径とした。In the following test, taking into consideration that the crushing of the graphite particles does not occur and that the fixing of the small particles is effectively performed, the rotation speed of the rotary shaft 6 is set so that the peripheral speed becomes 60 m / sec. Was adjusted and tested. The treatment time can be changed within a range of 1 to 20 minutes, but it is set to 3 minutes because the treatment effect can be sufficiently obtained even in a short time. The graphite powders thus surface-treated were evaluated by the following methods, and the results are shown in Tables 1 and 2. In addition, the particle size distribution of the powder is a laser diffraction type particle size distribution meter (manufactured by Microtrac,
Model 7997), and the particle size at the position where the cumulative volume is ½ was taken as the average particle size.
【００５３】ａ．ゼータ電位 衝撃処理された黒鉛質粉体または他の黒鉛質粉体１重量
部に対し０．０１モル濃度のＫＣｌ水溶液１０重量部を
加えて混合し泥漿を得た。この泥漿を３０分間減圧脱気
後、０．０１規定のＫＯＨ水溶液を添加してｐＨ１１に
調整し、泥漿の温度を２５℃に保持してコロイド振動電
位法によりゼータ電位を測定した。A. Zeta potential 10 parts by weight of 0.01 molar KCl aqueous solution was added to 1 part by weight of impact-treated graphite powder or other graphite powder and mixed to obtain a slurry. The sludge was degassed under reduced pressure for 30 minutes, 0.01 N KOH aqueous solution was added to adjust the pH to 11, the zeta potential was measured by the colloidal oscillation potential method while maintaining the sludge temperature at 25 ° C.
【００５４】ｂ．坏土の流動性 衝撃処理されて親水性の粒子が表面に固着された黒鉛質
粉体または他の黒鉛質粉体を６重量部、最大粒子径２０
ｍｍ最小粒子径４０μｍの電融マグネシアクリンカー８
６重量部、アルミナ微粉（平均粒子径約０．６μｍ）４
重量部、シリカ微粉（粒子径１μｍ以下）４重量部、金
属シリコン粉末（粒子径１４７μｍ以下）３重量部、結
合剤である乳酸１．５重量部、界面活性剤であるβ−ナ
フタリンスルホン酸塩０．１重量部および蒸留水８重量
部を、ともに万能ミキサー中に投入して１分間混合を行
い、チクソトロピー性を有する坏土を得た。B. Flowability of kneaded clay 6 parts by weight of graphite powder or other graphite powder having impact-treated hydrophilic particles adhered to the surface, maximum particle diameter 20
mm Fused magnesia clinker 8 with a minimum particle size of 40 μm
6 parts by weight, alumina fine powder (average particle size of about 0.6 μm) 4
Parts by weight, fine silica powder (particle size 1 μm or less) 4 parts by weight, metallic silicon powder (particle size 147 μm or less) 3 parts by weight, lactic acid as a binder 1.5 parts by weight, β-naphthalene sulfonate as a surfactant Both 0.1 part by weight and 8 parts by weight of distilled water were put into a universal mixer and mixed for 1 minute to obtain a kneaded clay having thixotropy.
【００５５】この坏土を内径１００ｍｍ深さ５０ｍｍの
型に充填し、型を取り外した状態の坏土に３Ｇの強さの
振動を１０秒間、上下方向に与えて軟化変形せしめ、坏
土の最大広がり幅を測定して流動性とした。This kneaded material was filled in a mold having an inner diameter of 100 mm and a depth of 50 mm, and vibration of 3 G strength was applied vertically to the kneaded material with the mold removed for 10 seconds to soften and deform the kneaded material. The spread width was measured and made into the fluidity.
【００５６】[0056]
【表１】 [Table 1]
【００５７】[0057]
【表２】 [Table 2]
【００５８】ｃ．乾燥比重 上記の坏土を５０ｍｍ×５０ｍｍ×５０ｍｍの内寸法を
有する型に振動鋳込みにより流し込み、室温で一昼夜放
置して硬化させて型から外し、１１０℃でさらに２４時
間乾燥した後、試験片の嵩比重を測定した。C. Dry Specific Gravity The above kneaded material was poured into a mold having an inner size of 50 mm × 50 mm × 50 mm by vibration casting, left standing at room temperature for one day to cure, removed from the mold, and dried at 110 ° C. for another 24 hours. Bulk specific gravity was measured.
【００５９】ｄ．耐酸化性 上記の、乾燥した試験片を空気中において１５００℃で
２時間加熱し、冷却後中央で切断して断面を調べ、酸化
されてできた脱炭層の深さを測定した。D. Oxidation resistance The dried test piece was heated in air at 1500 ° C. for 2 hours, cooled, cut at the center, and examined for a cross section, and the depth of the decarburized layer formed by oxidation was measured.
【００６０】以上の試験の結果から、本発明の黒鉛質粉
体は、一種類の親水性を有する粉体の粒子を黒鉛粉体の
粒子表面に固着して被覆した場合にも、二種類以上の親
水性を有する粉体の小粒子を黒鉛粉体の黒鉛粒子表面に
固着して被覆した場合にも、表面処理がなされていな
い、あるいは従来の有機物による表面処理がなされた黒
鉛質粉体と比べて、ゼータ電位の絶対値が大きいことが
明らかであり、水に対する分散性に優れていることが分
かった。From the results of the above test, the graphite powder of the present invention has two or more kinds even when particles of one kind of powder having hydrophilicity are fixed and coated on the particle surface of the graphite powder. Even when the small particles of the hydrophilic powder are adhered to and coated on the surface of the graphite particles of the graphite powder, the graphite powder is not surface-treated or is surface-treated with a conventional organic substance. In comparison, it was clear that the absolute value of the zeta potential was large, and it was found that the dispersibility in water was excellent.
【００６１】本発明の黒鉛質粉体を使用すると、得られ
る坏土の流動性が優れており、この坏土を成形して得ら
れる複合成形体は嵩比重が大きく、この複合成形体を耐
火物として使用する場合には耐食性と耐酸化性が優れて
いる。When the graphite powder of the present invention is used, the kneaded material obtained is excellent in fluidity, and the composite molded article obtained by molding this kneaded material has a large bulk specific gravity. When used as a product, it has excellent corrosion resistance and oxidation resistance.
【００６２】[0062]
【発明の効果】本発明の黒鉛質粉体は、水中におけるゼ
ータ電位の絶対値が大きいことにより、表面処理がされ
ていない黒鉛粉末や他の方法で表面処理された黒鉛質粉
体と比べ、分散媒として使いやすい水を分散媒に使用す
るとき優れた分散性を示す。EFFECTS OF THE INVENTION The graphite powder of the present invention has a large absolute value of zeta potential in water, so that the graphite powder is not surface-treated or is surface-treated by another method. It shows excellent dispersibility when water, which is easy to use as a dispersion medium, is used.
【００６３】したがって、分散媒として有機溶媒を使用
する場合と比べると作業環境は良好であり、この優れた
分散性を利用し、緻密であって耐食性に優れた、さらに
耐酸化性にも優れた複合材料を得ることが可能となる。Therefore, compared with the case where an organic solvent is used as a dispersion medium, the working environment is better, and by utilizing this excellent dispersibility, it is dense and excellent in corrosion resistance and also excellent in oxidation resistance. It is possible to obtain a composite material.
【００６４】また、本発明の黒鉛質粉体では、黒鉛粒子
表面に固着せしめる親水性の粒子の材質を選ぶことによ
って、あるいは二種以上の親水性の粒子を固着せしめる
ことにより、親水性以外の好ましい特性をも兼備する黒
鉛質粉体とすることが可能である。Further, in the graphite powder of the present invention, by selecting the material of the hydrophilic particles to be fixed on the surface of the graphite particles, or by fixing the two or more kinds of hydrophilic particles, the non-hydrophilic property can be obtained. It is possible to obtain a graphite powder that also has desirable characteristics.
【００６５】本発明の黒鉛粉体の親水化処理方法によれ
ば、このように水に対する分散性に優れた黒鉛質粉体を
簡便に、能率良く製造することができ、黒鉛粉体の黒鉛
粒子の形状がアスペクト比の大きい鱗片状、針状などを
していても、黒鉛粒子の形状を球状あるいは楕球状に近
づけるというアスペクト比を小さくする処理と、親水性
の小粒子を黒鉛粒子の表面に固着する処理とを同時に行
ない、分散媒として水を使用して複合成形体を製造する
際、充填性が良好で緻密な成形体が得られる黒鉛質粉体
を得ることができる。According to the method for hydrophilizing a graphite powder of the present invention, a graphite powder having excellent dispersibility in water can be simply and efficiently produced, and the graphite particles of the graphite powder can be produced. Even if the shape is scale-shaped or needle-shaped with a large aspect ratio, a treatment to reduce the aspect ratio by making the shape of the graphite particles closer to spherical or ellipsoidal, and hydrophilic small particles on the surface of the graphite particles When the process of fixing is performed at the same time and a composite molded body is produced using water as a dispersion medium, a graphite powder having a good filling property and a dense molded body can be obtained.
【００６６】また、黒鉛粉体の粒子表面に亀裂や凹凸が
存在するような場合には、衝撃処理を行なうことによっ
てこの部分に親水性の小粒子がめりこんで固着され、複
合成形体にしたときに気孔率が小さくなり、黒鉛粒子の
酸化による消耗を少なくするなどの効果もある。When cracks or irregularities are present on the surface of the graphite powder particles, impact treatment is performed to cause small hydrophilic particles to stick into and stick to this portion, and a composite molded article is obtained. In addition, the porosity is reduced, and there is an effect that the consumption of graphite particles due to oxidation is reduced.
【００６７】また、本発明の黒鉛粉体の親水化処理方法
では、種々の親水性粒子を黒鉛粒子の表面に固着せしめ
ることができることは勿論、二種以上の親水性粒子を同
時に、あるいは重ねて固着せしめ、被覆することがで
き、これによって黒鉛質粉体に水に対する分散性以外の
好ましい特性を兼備させることが可能である。In addition, in the method for hydrophilizing graphite powder of the present invention, various hydrophilic particles can be fixed to the surface of the graphite particles, as a matter of course, two or more kinds of hydrophilic particles are simultaneously or layered. It can be fixed and coated, which allows the graphite powder to have desirable properties other than dispersibility in water.
【図１】本発明の黒鉛粉体の親水化処理方法において使
用される装置の一例を示す正面断面図FIG. 1 is a front sectional view showing an example of an apparatus used in a method for hydrophilizing graphite powder according to the present invention.
【図２】図１の側面断面図FIG. 2 is a side sectional view of FIG.
１：ケーシング、 ２：前方壁、 ３：後方壁、 ４：回転板、 ５：ブレード、 ６：回転軸、 ７：衝撃室、 ８：衝撃壁、 ９：粉体出口弁、 １０：粉体循環回路管、 １１：原料粉体導入弁、 １２：ホッパー。 1: Casing, 2: Front wall, 3: Rear wall, 4: Rotating plate, 5: Blade, 6: Rotating shaft, 7: Impact chamber, 8: Impact wall, 9: Powder outlet valve, 10: Powder circulation Circuit tube, 11: Raw material powder introduction valve, 12: Hopper.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成４年１０月２３日[Submission date] October 23, 1992
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００９[Correction target item name] 0009
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００９】ＣＶＤ処理としては、たとえば黒鉛粒子の
表面とＳｉＯやＢ2 Ｏ3 などのガス成分とを１０００℃
以上の高温下で反応させ、その表面にＳｉＣやＢ4 Ｃな
どの薄膜を生成せしめることが行なわれており、ゼータ
電位の絶対値が大きい粉体が得られているが、同時に黒
鉛粒子の表面が酸化されて密度の低い荒れた表面組織が
できて耐酸化性が低下するなどの問題がある。As the CVD treatment, for example, the surface of graphite particles and a gas component such as SiO or B 2 O 3 are heated to 1000 ° C.
It has been performed that the reaction is performed under the above high temperature to form a thin film such as SiC or B 4 C on the surface, and powder having a large absolute value of zeta potential is obtained. However, there is a problem in that a rough surface structure with a low density is formed due to the oxidation of the slag and the oxidation resistance is reduced.
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１１[Correction target item name] 0011
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１１】湿式ゾルゲル処理法では、たとえばシリコ
ンアルコキシド、アルミニウムアルコキシドなどを酸触
媒の存在下でアルコール水溶液と反応させて加水分解
し、ゾル溶液とした処理液を黒鉛粉体に含浸せしめ、乾
燥してゲル化し、黒鉛粒子の表面にＳｉＯ2 やＡｌ2 Ｏ
3 などを付着せしめることができるが、黒鉛粒子と処理
液との濡れ性が悪く、黒鉛粒子の表面と被覆層の間にミ
クロの気孔が形成されたり、被覆層そのものに気孔がで
きたりすることによって、黒鉛粒子の水に対する良好な
分散性が得られないとともに、この黒鉛質粉体（以下表
面処理された黒鉛粒子からなる粉体をを黒鉛質粉体とい
う。）を使用すると成形体の気孔率が大きくなるという
問題がある。In the wet sol-gel treatment method, for example, silicon alkoxide, aluminum alkoxide, etc. are hydrolyzed by reacting with an aqueous alcohol solution in the presence of an acid catalyst to impregnate the graphite powder with the treatment solution as a sol solution, followed by drying. Gelled and the surface of the graphite particles was SiO 2 or Al 2 O
Although 3 etc. can be attached, the wettability between the graphite particles and the treatment liquid is poor, and micro pores may be formed between the surface of the graphite particles and the coating layer, or pores may be formed in the coating layer itself. As a result, good dispersibility of the graphite particles in water cannot be obtained, and when this graphite powder (hereinafter, the powder comprising the surface-treated graphite particles is referred to as graphite powder) is used, the pores of the molded body are There is a problem that the rate becomes large.
【手続補正３】[Procedure 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００５７[Correction target item name] 0057
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００５７】[0057]
【表２】 [Table 2]
Claims (6)
子の表面に、黒鉛粒子より平均粒子径が小さく、かつ親
水性を有する小粒子が固着されていることを特徴とする
黒鉛質粉体。1. A powder comprising graphite particles, characterized in that small particles having an average particle size smaller than that of the graphite particles and having hydrophilicity are fixed to the surface of the graphite particles. powder.
が金属酸化物、金属炭化物、金属窒化物、金属硼化物お
よび金属の中から選ばれる一種以上からなるものである
黒鉛質粉体。2. The graphite powder according to claim 1, wherein the hydrophilic small particles are one or more selected from metal oxides, metal carbides, metal nitrides, metal borides and metals.
る小粒子の平均粒子径が黒鉛粒子の平均粒子径の２０％
以下である黒鉛質粉体。3. The average particle size of small particles having hydrophilicity according to claim 1 or 2, which is 20% of the average particle size of graphite particles.
The following are graphitic powders.
鉛粒子が天然の鱗片状黒鉛である黒鉛質粉体。4. The graphite powder according to claim 1, wherein the graphite particles are natural flake graphite.
小さい平均粒子径を有する親水性を有する小粒子からな
る粉体との混合粉体を高速気流中に投入し、粉体粒子の
衝撃処理を行なうことを特徴とする黒鉛粉体の親水化処
理方法。5. A mixed powder of a powder composed of graphite particles and a powder composed of hydrophilic small particles having an average particle size smaller than that of the graphite particles is put into a high-speed air stream to obtain powder particles. A method for hydrophilizing graphite powder, which comprises subjecting to impact treatment.
けて繰り返し行なう黒鉛粉体の親水化処理方法。6. The method for hydrophilizing graphite powder according to claim 5, wherein the impact treatment is repeated a plurality of times.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4224654A JPH05213611A (en) | 1991-08-09 | 1992-07-31 | Treatment of graphitic powder and graphite powder for making them hydrophilic |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3-223681 | 1991-08-09 | ||
| JP22368191 | 1991-08-09 | ||
| JP4224654A JPH05213611A (en) | 1991-08-09 | 1992-07-31 | Treatment of graphitic powder and graphite powder for making them hydrophilic |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05213611A true JPH05213611A (en) | 1993-08-24 |
Family
ID=26525624
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4224654A Pending JPH05213611A (en) | 1991-08-09 | 1992-07-31 | Treatment of graphitic powder and graphite powder for making them hydrophilic |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05213611A (en) |
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