JP2922096B2 - Method for producing hexagonal boron nitride powder - Google Patents
Method for producing hexagonal boron nitride powderInfo
- Publication number
- JP2922096B2 JP2922096B2 JP20682393A JP20682393A JP2922096B2 JP 2922096 B2 JP2922096 B2 JP 2922096B2 JP 20682393 A JP20682393 A JP 20682393A JP 20682393 A JP20682393 A JP 20682393A JP 2922096 B2 JP2922096 B2 JP 2922096B2
- Authority
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- Japan
- Prior art keywords
- powder
- boron nitride
- heat treatment
- nitride powder
- hexagonal boron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【０００１】[0001]
【産業上の利用分野】本発明は、１次粒子径が大きい、
高結晶性窒化硼素粉末で、潤滑性、充填性に優れた窒化
硼素粉末の製造方法に関するものである。BACKGROUND OF THE INVENTION The present invention relates to a large primary particle size,
The present invention relates to a method for producing a boron nitride powder having high crystallinity and excellent lubricity and filling properties.
【０００２】[0002]
【従来の技術】六方晶窒化硼素（以下窒化硼素をＢＮと
いう）粉末は白色で黒鉛と同様に層状構造であり種々の
特性を有している。特に熱伝導性、電気絶縁性、化学安
定性、潤滑性、耐熱性などが優れており、これらの性質
を生かして多岐の用途に供されている。粉末としての用
途にはプラスチック添加剤、潤滑剤などの他に、化粧品
用途がある。2. Description of the Related Art Hexagonal boron nitride (hereinafter referred to as BN) powder is white, has a layered structure like graphite, and has various characteristics. In particular, it has excellent heat conductivity, electrical insulation, chemical stability, lubricity, heat resistance, and the like, and is used for a variety of applications by utilizing these properties. Powder applications include cosmetics applications in addition to plastic additives and lubricants.
【０００３】最近では電子技術の進歩に従って、ＢＮの
耐熱性、電気絶縁性を利用した充填剤、添加剤の用途に
おいて高純度のＢＮの要求が多くなってきている。例え
ば合成ゴムにＢＮ粉末を添加して電気絶縁性及び熱伝導
性の優れたシートを製造する方法がある（特開昭５４−
１６３３９８号公報）。このとき使用するＢＮ粉末に要
求される特性は、（イ）表面を平滑にして合成ゴムとの
密着性を良くすること、（ロ）高結晶質で大粒子ＢＮを
使用し熱伝導性、電気絶縁性に優れた特性を付与するこ
と、である。[0003] In recent years, with the progress of electronic technology, there has been an increasing demand for high-purity BN in applications of fillers and additives utilizing the heat resistance and electrical insulation properties of BN. For example, there is a method of manufacturing a sheet having excellent electrical insulation and thermal conductivity by adding BN powder to synthetic rubber (Japanese Patent Application Laid-Open No. 54-1979).
163398). The characteristics required for the BN powder used at this time are (a) to improve the adhesiveness to the synthetic rubber by smoothing the surface, and (ii) to use the highly crystalline and large-particle BN, Imparting excellent properties to insulation.
【０００４】合成ゴムとの密着性や、シートの熱伝導
性、電気絶縁性は、ＢＮの粒径に依存する場合が多い。
大粒径ほどゴムシートに充填した場合、シートの熱伝導
率は高くなる。従来、このような用途に適するＢＮの製
造には、次の方法がある。 （１）潤滑性を有しないＢＮ粉末にアルカリ土類金属を
混合し、これを成形して、加熱処理を行った後、粉砕、
分級してＢＮ粉末を得る方法（特開昭６０−３３２０４
号公報、特開昭６１−７２６０５号公報）。 （２）硼素化合物、炭素、Ｎ2 による還元窒化法でＢＮ
を製造する場合に、炭素粒子径を制御してＢＮ粒子を制
御する方法（特開平４−１６５０２号公報）。 （３）硼素化合物と窒素化合物の混合物にＣａ含有化合
物を添加し、熱処理を行い、焼結体用のＣａ化合物を含
むＢＮ粉末を製造する方法（特開昭６１−７２６０６号
公報）。 （４）硼酸を原料とするＢＮ粉末を水洗して硼酸アンモ
ニウムを除去した後、１５００〜１８００℃で熱処理を
行い、高結晶性ＢＮを製造する方法（特開昭６１−７２
６０４号公報）。[0004] Adhesion with synthetic rubber, thermal conductivity and electrical insulation of a sheet often depend on the particle size of BN.
When a rubber sheet is filled with a larger particle size, the thermal conductivity of the sheet increases. Conventionally, there are the following methods for producing BN suitable for such applications. (1) Alkaline earth metal is mixed with BN powder having no lubricity, molded, heated, pulverized,
Method for obtaining BN powder by classification (JP-A-60-33204)
JP-A-61-72605). (2) BN by reduction nitriding with boron compound, carbon and N 2
A method of controlling BN particles by controlling the diameter of carbon particles when manufacturing (JP-A-4-16502). (3) A method of adding a Ca-containing compound to a mixture of a boron compound and a nitrogen compound and performing a heat treatment to produce a BN powder containing a Ca compound for a sintered body (JP-A-61-72606). (4) A method for producing high crystalline BN by washing BN powder using boric acid as a raw material with water to remove ammonium borate and then performing a heat treatment at 1500 to 1800 ° C (Japanese Patent Laid-Open No. 61-72).
604).
【０００５】[0005]
【発明が解決しようとする課題】前記（１）法は、結晶
未発達のＢＮを成形し、熱処理を行った後、粉砕、分級
する方法であり、粉砕、分級の程度により、任意の粒径
を得ることができる。しかしながら、成形体の作成工程
が複雑になること、粉砕でエネルギーコストがかかるこ
と及び、粉砕・分級を行っても完全な一次粒子にならな
いことなどの欠点がある。前記（２）法は、炭素粒子を
添加し、その粒子径でＢＮ粒子を制御する方法である。
この場合、炭素を完全に除去することが難しく、ＢＮ粉
末の用途によっては、問題になる場合もある。また、残
留炭素の作用で、ＢＮが黄色に変化し、ＢＮ本来の白色
イメージを損なう場合もある。前記（３）法は、Ｃａ含
有化合物を添加し、その後熱処理を行う方法について
は、本発明と類似であるが、製造粉末の形態が異なって
いる。前記（４）法は、水洗により不純物を除去し、そ
の後、加熱処理を行うプロセスについては、本発明と類
似であるが、不純物が硼酸アンモニウムである点が異な
っている。以上の如く、公知のＢＮ製造方法では、本発
明のような大粒径ＢＮの製造が不可能である。The above-mentioned method (1) is a method in which BN with an undeveloped crystal is formed, heat-treated, and then pulverized and classified. Depending on the degree of pulverization and classification, an arbitrary particle size is obtained. Can be obtained. However, there are drawbacks such as that the process of forming a molded article is complicated, that energy costs are required for pulverization, and that primary particles are not completely formed even after pulverization and classification. The method (2) is a method in which carbon particles are added and BN particles are controlled by the particle diameter.
In this case, it is difficult to completely remove carbon, which may cause a problem depending on the use of the BN powder. In addition, BN changes to yellow due to the effect of the residual carbon, which may impair the original white image of BN. The method (3) is similar to the method of the present invention in that a Ca-containing compound is added and then heat treatment is performed, but the form of the produced powder is different. In the method (4), a process of removing impurities by washing with water and then performing a heat treatment is similar to the present invention, except that the impurities are ammonium borate. As described above, the known BN production method cannot produce BN having a large particle size as in the present invention.
【０００６】[0006]
【課題を解決するための手段】本発明は平均一次粒子径
１０〜３０μｍのＢＮ粉末の製法に関するものであり、
このような一次粒子が大粒径のＢＮの製造方法は今まで
存在しない。粗製六方晶ＢＮ（結晶の発達が不十分であ
り、かつＢＮＯ，Ｂ2 Ｏ3 のような不純物が存在するも
の）にＣａ含有化合物を混合し、熱処理を行い、Ｃａと
粗製ＢＮの不純物とを反応させて、硼酸Ｃａ化合物を生
成する。生成物中には未反応のＣａが存在するので、こ
れを水洗で除去する。この未反応Ｃａが存在すると、次
の加熱処理工程における粒成長に悪影響を及ぼす。つま
り、粒成長の際の液相量及び液組成分が不十分であり、
本発明の粒子径を得ることができない。本発明は、大粒
子ＢＮを製造する際に硼酸Ｃａのみが有効でそれ以外の
物質を水洗浄除去することがポイントである。The present invention relates to a method for producing BN powder having an average primary particle diameter of 10 to 30 μm,
There is no method for producing BN having such a large primary particle size. A Ca-containing compound is mixed with crude hexagonal BN (having insufficient crystal development and impurities such as BNO and B 2 O 3 ) and heat-treated to remove Ca and impurities of the crude BN. The reaction produces a Ca borate compound. Since unreacted Ca is present in the product, it is removed by washing with water. The presence of this unreacted Ca adversely affects the grain growth in the next heat treatment step. In other words, the liquid phase amount and liquid composition during grain growth are insufficient,
The particle size of the present invention cannot be obtained. The point of the present invention is that only Ca borate is effective in producing large particles BN, and the other substances are washed and removed with water.
【０００７】[0007]
【作用】本発明は一次粒子径１０〜３０μｍのＢＮ粉末
の製法に関するものである。ここで粒子径とは粒度分布
をもったＢＮ粉末の平均粒径のことであり、一次粒子径
とはＢＮ粉末特有の鱗片状の自形を有していて、凝集粒
になっていない粒子の径である。粒度分布の測定はＢＮ
粉末をエタノール液あるいは分散剤添加の水溶液中に入
れ、超音波振動をかけて均一に分散させ、マイクロトラ
ック法で測定し、重量基準の５０％径を平均粒子径とし
た。The present invention relates to a method for producing BN powder having a primary particle diameter of 10 to 30 μm. Here, the particle diameter is the average particle diameter of the BN powder having a particle size distribution, and the primary particle diameter is a particle having a flake-like self-shape unique to the BN powder and not being agglomerated. Is the diameter. Measurement of particle size distribution is BN
The powder was placed in an ethanol solution or an aqueous solution to which a dispersant was added, and was uniformly dispersed by ultrasonic vibration. The powder was measured by a microtrack method, and the 50% diameter based on weight was defined as the average particle diameter.
【０００８】以下に本発明の詳細を製造工程に準じて説
明する。原料である粗製六方晶ＢＮは通常８００℃〜１
２００℃で合成して得られたものであり、結晶は完全に
は六方晶となっておらず乱層構造を有している。結晶子
の大きさＬｃ（学振炭素材料１１７委員会試料による方
法で測定した値）は５０Å〜１００Åと小さく、一次粒
子径の大きさも１００Å前後の微粒になっている。純度
については試料中の窒素分析から求めると５０〜９５重
量％の範囲であった。不純物としては酸素がほとんどで
あり、存在形態としては硼酸アンモニウム、酸化硼素、
Ｂ−Ｎ−Ｘ系生成物などである。The details of the present invention will be described below according to the manufacturing process. Raw hexagonal BN as a raw material is usually 800 ° C to 1 ° C.
It is obtained by synthesis at 200 ° C., and the crystal is not completely hexagonal and has a turbostratic structure. The crystallite size Lc (measured by a method using a sample of the Gakushin Carbon Materials 117 Committee) is as small as 50 ° to 100 °, and the size of the primary particle size is also about 100 °. The purity was in the range of 50 to 95% by weight as determined from analysis of nitrogen in the sample. Most of the impurities are oxygen, and there are ammonium borate, boron oxide,
And BNX-based products.
【０００９】次に、粗製ＢＮに対してＣａ含有化合物を
添加して混合する。Ｃａ含有化合物としては、酸化物、
窒化物、炭化物、フッ化物のどれでも可能であるが、こ
の混合物を次の工程において１３００〜１８００℃で熱
処理した際に、Ｃａ含有化合物と粗製ＢＮ中の不純物と
が反応してＣａＯ・ｎＢ2 Ｏ3 を生成することが必要で
ある。熱処理温度が１３００℃未満では反応が十分に進
まず、収率が悪く、一方、１８００℃を越えると、Ｂ2
Ｏ3 の蒸発が起こり、収率が悪い。次に、水洗浄工程で
不純物を除去する。不純物としては、ＣａＯ・ｎＢ2 Ｏ
3を生成せずに未反応で残存するＣａＯ、Ｃａ（ＯＨ）2
、Ｂ2 Ｏ3 、ＮＨ4 Ｂ4Ｏ7 などの水可溶物である。水
洗浄工程を通さずに、不純物が存在するままで、次工程
の加熱処理を行っても、所望の粒子径を有するＢＮの生
成は不可能であった。Next, a Ca-containing compound is added to the crude BN and mixed. As Ca-containing compounds, oxides,
Any of nitrides, carbides and fluorides can be used, but when this mixture is heat-treated at 1300 to 1800 ° C. in the next step, the Ca-containing compound reacts with impurities in the crude BN to produce CaO.nB 2. It is necessary to generate O 3 . If the heat treatment temperature is lower than 1300 ° C., the reaction does not proceed sufficiently and the yield is poor, while if it exceeds 1800 ° C., B 2
Evaporation of O 3 takes place, is bad yield. Next, impurities are removed in a water washing step. As impurities, CaO.nB 2 O
CaO, Ca (OH) 2 remaining unreacted without producing 3
, B 2 O 3 , and NH 4 B 4 O 7 . Even if the heat treatment in the next step is performed in the presence of impurities without passing through the water washing step, it is impossible to generate BN having a desired particle diameter.
【００１０】一次粒子径の大きいＢＮは、加熱により液
相中でＢＮの結晶子Ｌｃの粒成長により生成する。粒子
径１０μｍ未満のＢＮはＢ2 Ｏ3 液相で生成が可能であ
るが、本発明のように１０〜３０μｍの大粒子はＢ2 Ｏ
3 液相ではＢ2 Ｏ3 が蒸発を伴ない、液相量が減少する
ために不可能であり、ＣａＯ・ｎＢ2 Ｏ3 液相（ｎは１
／３〜３の範囲）で可能である。その理由はＣａＯ・ｎ
Ｂ2 Ｏ3 成分の液相は熱処理温度１８００〜２１００℃
の範囲で安定して存在するために、ＢＮ結晶子の焼結や
合体により粒成長が促進するからである。熱処理温度は
１８００〜２１００℃が適温であり、１８００℃未満で
は液相が十分に生成しないために粒成長が起こらず２１
００℃を越えると、ＣａＯ・ｎＢ2 Ｏ3 の蒸発により液
相が少くなり粒成長が起こらない。[0010] BN having a large primary particle diameter is generated by the growth of BN crystallites Lc in a liquid phase by heating. Although BN particles having a particle size of less than 10μm are possible generated by B 2 O 3 liquid phases, large particles of 10~30μm as in the present invention are B 2 O
In the three liquid phases, B 2 O 3 is not allowed to evaporate and the amount of the liquid phase is reduced, so that the CaO · nB 2 O 3 liquid phase (n is 1
/ 3 to 3). The reason is CaO ・ n
The liquid phase of the B 2 O 3 component has a heat treatment temperature of 1800 to 2100 ° C.
This is because grain growth is promoted by sintering or coalescence of BN crystallites because they are stably present in the range. The optimal temperature for the heat treatment is 1800 to 2100 ° C. If the temperature is lower than 1800 ° C., the liquid phase is not sufficiently formed, so that grain growth does not occur and 21 ° C.
When the temperature exceeds 00 ° C., the liquid phase decreases due to evaporation of CaO.nB 2 O 3 , and no grain growth occurs.
【００１１】[0011]
【実施例】８００℃で合成した粗製ＢＮ（Ｏ＝１６％、
Ｌｃ＝９２Å）１０ｋｇに対し、ＣａＣＯ3 を１０％添
加してロッキングミキサで１Ｈｒ混合した。炭素質坩堝
に充填し、Ｎ2 中で所定温度、時間に渡り１次加熱処理
を行った。ピンミルで解砕の後、撹拌翼付き水槽（水／
固体＝３）で洗浄を行い、フィルタプレスで脱水濾過後
１０時間乾燥した。次にＢＮコートした炭素質坩堝に充
填し、Ｎ2 中で所定温度、時間に渡り、２次加熱処理を
行った。EXAMPLES Crude BN synthesized at 800 ° C. (O = 16%,
Lc = 92 °) 10 kg of CaCO 3 was added to 10 kg and mixed for 1 hour by a rocking mixer. The mixture was filled in a carbonaceous crucible and subjected to primary heat treatment in N 2 at a predetermined temperature for a predetermined time. After crushing with a pin mill, a water tank with stirring blades (water /
The solid was washed with 3), dehydrated and filtered with a filter press, and then dried for 10 hours. Next, the mixture was filled in a carbonaceous crucible coated with BN, and subjected to a second heat treatment in N 2 at a predetermined temperature for a predetermined time.
【００１２】ピンミルで解砕し、微粉状にし、電子顕微
鏡観察、粒度分析（マイクロトラック法）およびＸ線結
晶子（Ｌｃ）測定を行った。結果を比較例とともに表１
に示した。実施例では図１に示すような、一次粒子径１
０μｍ以上のＢＮを得た。図１は、倍率２０００倍の電
子顕微鏡観察写真である。本発明の範囲外の条件では一
次粒子径１０μｍ以上のものを得ることができなかっ
た。The mixture was pulverized with a pin mill to make a fine powder, and observed by an electron microscope, particle size analysis (microtrack method) and X-ray crystallite (Lc) measurement. Table 1 shows the results together with comparative examples.
It was shown to. In the example, as shown in FIG.
BN of 0 μm or more was obtained. FIG. 1 is an electron microscope observation photograph at a magnification of 2000 times. Under conditions outside the range of the present invention, particles having a primary particle diameter of 10 μm or more could not be obtained.
【００１３】[0013]
【表１】 [Table 1]
【００１４】[0014]
【発明の効果】本発明によれば、Ｃａ系添加物による液
相の生成および加熱処理条件を設定することによって、
従来製造できなかった一次粒子径１０〜３０μｍの高結
晶性ＢＮ粉末を製造することができるようになった。こ
のＢＮは高結晶性であり潤滑性、充填性にすぐれ、高熱
伝導性、化学安定性にもすぐれ広範な用途に用いること
ができる。According to the present invention, the generation of the liquid phase by the Ca-based additive and the setting of the heat treatment conditions enable the
It has become possible to produce a highly crystalline BN powder having a primary particle diameter of 10 to 30 μm, which could not be produced conventionally. This BN is highly crystalline, has excellent lubricity and filling properties, has excellent thermal conductivity and chemical stability, and can be used for a wide range of applications.
【図１】倍率２０００倍の電子顕微鏡観察写真である。FIG. 1 is an electron microscope observation photograph at a magnification of 2000 times.
Claims (1)
合物を混合し、この混合物を非酸化性雰囲気中で１３０
０〜１８００℃の温度範囲で加熱処理した後、水洗浄処
理を行い、さらに非酸化性雰囲気で１８００〜２１００
℃の温度範囲で加熱処理を行って、一次粒子径１０〜３
０μｍの窒化硼素粉末を得ることを特徴とする窒化硼素
の製造方法。1. A crude hexagonal boron nitride powder is mixed with a Ca-containing compound, and the mixture is mixed in a non-oxidizing atmosphere at 130.degree.
After performing a heat treatment in a temperature range of 0 to 1800 ° C., a water washing treatment is performed, and further, in a non-oxidizing atmosphere, 1800 to 2100 ° C.
Heat treatment in a temperature range of 10 ° C. to obtain a primary particle diameter of 10 to 3
A method for producing boron nitride, comprising obtaining 0 μm boron nitride powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20682393A JP2922096B2 (en) | 1993-07-30 | 1993-07-30 | Method for producing hexagonal boron nitride powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20682393A JP2922096B2 (en) | 1993-07-30 | 1993-07-30 | Method for producing hexagonal boron nitride powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0741311A JPH0741311A (en) | 1995-02-10 |
| JP2922096B2 true JP2922096B2 (en) | 1999-07-19 |
Family
ID=16529677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20682393A Expired - Fee Related JP2922096B2 (en) | 1993-07-30 | 1993-07-30 | Method for producing hexagonal boron nitride powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2922096B2 (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4202521B2 (en) * | 1999-04-08 | 2008-12-24 | 昭和電工株式会社 | Method for producing cubic boron nitride |
| US6645612B2 (en) * | 2001-08-07 | 2003-11-11 | Saint-Gobain Ceramics & Plastics, Inc. | High solids hBN slurry, hBN paste, spherical hBN powder, and methods of making and using them |
| US7494635B2 (en) | 2003-08-21 | 2009-02-24 | Saint-Gobain Ceramics & Plastics, Inc. | Boron nitride agglomerated powder |
| JP2008174448A (en) * | 2008-04-08 | 2008-07-31 | Osamu Yamamoto | Crystalline turbostratically structured boron nitride |
| JP5065198B2 (en) * | 2008-08-04 | 2012-10-31 | 株式会社カネカ | Method for producing hexagonal boron nitride |
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1993
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