JP3373767B2 - Method for producing inorganic oxide fine powder - Google Patents
Method for producing inorganic oxide fine powderInfo
- Publication number
- JP3373767B2 JP3373767B2 JP25426997A JP25426997A JP3373767B2 JP 3373767 B2 JP3373767 B2 JP 3373767B2 JP 25426997 A JP25426997 A JP 25426997A JP 25426997 A JP25426997 A JP 25426997A JP 3373767 B2 JP3373767 B2 JP 3373767B2
- Authority
- JP
- Japan
- Prior art keywords
- sol
- inorganic oxide
- oxide
- hydroxide
- fine powder
- 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 - Lifetime
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- Oxygen, Ozone, And Oxides In General (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、無機酸化物ゾルに
有機増粘剤を添加し、ついで５００℃以上の温度で焼成
することにより、無機酸化物微粉末を製造する方法に関
する。TECHNICAL FIELD The present invention relates to a method for producing an inorganic oxide fine powder by adding an organic thickener to an inorganic oxide sol and then calcining at a temperature of 500 ° C. or higher.
【０００２】[0002]
【従来の技術】これまで無機酸化物ゾルから無機酸化物
微粉末を製造する方法として、無機酸化物のゾルを凍結
乾燥する方法などが知られている。しかしながら、凍結
乾燥法では、ゾル濃度を希薄にすればそれだけ分散性に
優れた微粉末が得られるものの、生成物に比較して非常
に大量の水を凍結し真空乾燥することから、これに費や
すエネルギーはばく大であり、分散性と経済性の両立が
とれなかった。2. Description of the Related Art Up to now, as a method for producing an inorganic oxide fine powder from an inorganic oxide sol, a method of freeze-drying an inorganic oxide sol has been known. However, in the freeze-drying method, although a fine powder having excellent dispersibility can be obtained by diluting the sol concentration, a very large amount of water is frozen and vacuum-dried in comparison with the product, so this is spent. The energy was enormous and it was not possible to achieve both dispersibility and economy.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、分散性に優
れた無機酸化物微粉末を工業的かつ経済的に製造する方
法を提供することを目的としている。SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for industrially and economically producing an inorganic oxide fine powder having excellent dispersibility.
【０００４】[0004]
【課題を解決するための手段】本発明者は、かかる課題
について鋭意研究を重ねた結果、無機酸化物ゾルに有機
増粘剤を添加して系内で有機ゲルを形成し、ついでこの
ゲルを焼成することにより、ゲル中の水を蒸発させ、引
き続き有機物を焼き尽くして、無機酸化物の二次凝集を
抑えながらゾル中の無機粒子を微粉末として回収し得る
ことを見い出し、この知見に基づいて本発明をなすに至
った。すなわち本発明は、無機酸化物ゾルに有機増粘剤
を添加して、無機酸化物ゾルをゲル化し、次いで、得ら
れたゲルを５００℃以上の温度で焼成して、ゲルに含ま
れる有機増粘剤を燃焼させる、無機酸化物微粉末の製造
方法である。Means for Solving the Problems As a result of intensive studies on such problems, the present inventor has added an organic thickener to an inorganic oxide sol to form an organic gel in the system, and then formed this gel. By firing, it was found that the water in the gel is evaporated, the organic matter is subsequently burned out, and the inorganic particles in the sol can be recovered as fine powder while suppressing the secondary aggregation of the inorganic oxide, and based on this finding The present invention has been completed. That is, the present invention is to add an organic thickener to the inorganic oxide sol to gel the inorganic oxide sol, and then obtain
The gel was calcined at 500 ° C. or higher temperatures and in the gel
Of fine powder of inorganic oxide by burning organic thickener
Is the way .
【０００５】[0005]
【発明の実施の形態】本発明においては、先ず、無機酸
化物ゾルに有機増粘剤を添加してゾル中の無機粒子を均
一に分散させた状態でゲル化する。本発明において用い
られる無機酸化物ゾルは、乾燥または焼成により目的と
する酸化物になるようなものであり、例えば、酸化チタ
ン微粉末を得ようとする場合には、酸化チタンゾルまた
は水酸化チタンゾルを用いる。その他、目的とする酸化
物微粉末により、酸化亜鉛ゾル、酸化鉄ゾル、シリカゾ
ル、アルミナゾル或いはそれぞれの水酸化物ゾルなどが
用いられる。なお本発明でいう酸化物とは、酸化物の
他、水和酸化物、含水酸化物、水酸化物などを総称した
ものをいう。また、無機酸化物ゾルの一次粒子の形状
は、粒状（球状）、針状（棒状）、薄片状（板状）、紡
錘状など、あらゆる形状のものを用いることができる。
ゾルの固形分濃度は普通１〜３０重量％のものが適当で
ある。これより固形分濃度が小さくなり過ぎると後記す
る焼成工程での熱源、装置等で経済的でなくなり、また
大きくなり過ぎると無機粒子の分散が不安定となるので
好ましくない。BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, first, an organic thickener is added to an inorganic oxide sol to gel the inorganic particles in the sol in a uniformly dispersed state. The inorganic oxide sol used in the present invention is such that it becomes the target oxide by drying or firing, and, for example, in the case of obtaining titanium oxide fine powder, titanium oxide sol or titanium hydroxide sol is used. To use. In addition, zinc oxide sol, iron oxide sol, silica sol, alumina sol, or respective hydroxide sol may be used depending on the intended oxide fine powder. The oxide as used in the present invention is a generic term for a hydrated oxide, a hydrous oxide, a hydroxide and the like in addition to the oxide. In addition, the shape of the primary particles of the inorganic oxide sol may be any shape such as granular (spherical), needle-like (rod-like), flaky (plate-like), and spindle-like.
The solid concentration of the sol is usually 1 to 30% by weight. If the solid content concentration is too low, the heat source and apparatus in the firing step, which will be described later, becomes uneconomical, and if it is too high, the dispersion of the inorganic particles becomes unstable, which is not preferable.
【０００６】本発明において用いられるゾル中の無機酸
化物は、その粒子が粒状の場合は、粒子径が０．００５
〜０．２μｍのものであり、薄片状の場合は、縦の長さ
が０．１〜１００μｍ、横の長さが０．１〜１００μ
ｍ、厚みが０．０００５〜０．２μｍのものであり、針
状の場合は、長軸の長さが０．１〜１０μｍであり、軸
比が５〜５０のものであり、紡錘状の場合は、長軸の長
さが０．０１〜１μｍであり、軸比が２〜１０のもので
ある。一般に、無機酸化物ゾルには、ゾルの安定化剤、
ｐＨ調節剤等の成分が添加されているが、本発明におい
ては、このような成分を含んでいてもそのまま使用する
ことができる。The inorganic oxide in the sol used in the present invention has a particle size of 0.005 when the particles are granular.
In the case of a flaky shape, the vertical length is 0.1 to 100 μm, and the horizontal length is 0.1 to 100 μm.
m, the thickness is 0.0005 to 0.2 μm, and in the case of needles, the major axis length is 0.1 to 10 μm, the axial ratio is 5 to 50, and the spindle-shaped. In this case, the major axis length is 0.01 to 1 μm and the axial ratio is 2 to 10. Generally, for inorganic oxide sols, sol stabilizers,
Ingredients such as a pH adjusting agent are added, but in the present invention, even if such ingredients are included, they can be used as they are.
【０００７】本発明において用いられる有機増粘剤は、
例えば、ステアリン酸、ステアリルアミン、ゼラチン、
ヒドロキシエチルセルロース、ポリビニルアルコールな
どがあげられるが、これらはゾルに添加することによ
り、ゾルを構成する無機物粒子の分散性を損なわずに、
ゾルをゲル化するようなものであり、ゾルの種類、形態
などによって選択する必要がある。例えば、酸性水酸化
チタンゾルに対しては、ステアリルアミンなどが、水酸
化鉄ゾルに対しては、水酸化鉄粒子が電荷反発により分
散していることから、アルキルセルロース化合物や高分
子多糖類などの非イオン性の有機増粘剤が用いられる。The organic thickener used in the present invention is
For example, stearic acid, stearylamine, gelatin,
Hydroxyethyl cellulose, polyvinyl alcohol and the like can be mentioned, but by adding these to the sol, without impairing the dispersibility of the inorganic particles constituting the sol,
It is like gelating a sol, and it must be selected according to the type and form of the sol. For example, stearylamine or the like is used for acidic titanium hydroxide sol, and iron hydroxide particles are dispersed for iron hydroxide sol due to charge repulsion. A nonionic organic thickener is used.
【０００８】本発明方法において、有機増粘剤は無機酸
化物粒子の各粒子間に存在して各粒子の二次凝集を防ぐ
作用をする。すなわち、ゾルに有機増粘剤を添加してゾ
ルをゲル化し、得られたゲルを焼成すると先ず水が蒸発
する。次に、ゲルを構成する無機物粒子間に存在する該
有機増粘剤は、無機物粒子の二次凝集を防ぎつつ徐々に
燃焼して（燃え尽きて）二次凝集の少ない無機物微粉末
を得ることができる。従って、粒子と粒子を接触させな
いために十分な量の有機増粘剤を配合することが望まし
いが、逆に多く配合しすぎると、生産効率、コストの点
で好ましくない。有機増粘剤は、無機酸化物ゾルの固形
分の体積基準で５０〜１０００％、好ましくは１００〜
３００％の範囲で配合するのが望ましい。また、有機増
粘剤は、焼成により水より後に燃え尽きる必要があるこ
とから沸点が１００℃を越えるもの、望ましくは２００
℃以上の引火点をもつものが適している。更には、灰分
が少ないものがよい。灰分としては、１％以下、望まし
くは０．０１〜０．１％である。有機増粘剤をゾルに添
加する際に、ゾルを例えば４０〜９０℃に加熱しながら
添加して該増粘剤のゾルとの混合を促進することができ
る。In the method of the present invention, the organic thickener is present between the particles of the inorganic oxide particles and acts to prevent the secondary aggregation of the particles. That is, when an organic thickener is added to the sol to gelate the sol and the gel obtained is fired, water is first evaporated. Next, the organic thickening agent present between the inorganic particles forming the gel may gradually burn (burn out) while preventing secondary aggregation of the inorganic particles to obtain an inorganic fine powder with less secondary aggregation. it can. Therefore, it is desirable to add a sufficient amount of the organic thickener to prevent the particles from coming into contact with each other, but if too much is added, it is not preferable in terms of production efficiency and cost. The organic thickener is 50 to 1000%, preferably 100 to 1000% by volume based on the solid content of the inorganic oxide sol.
It is desirable to mix in the range of 300%. Further, the organic thickener has a boiling point of more than 100 ° C., preferably 200, because it needs to be burned out after water by firing.
Those with a flash point above ℃ are suitable. Furthermore, those with a low ash content are preferable. The ash content is 1% or less, preferably 0.01 to 0.1%. When the organic thickener is added to the sol, the sol can be added while heating to, for example, 40 to 90 ° C. to promote the mixing of the thickener with the sol.
【０００９】本発明においては無機粒子が均一に分散し
ているゲルを焼成して無機粒子を微粉末として回収す
る。焼成は、５００℃以上の温度で、普通５００〜１２
００℃、望ましくは６００〜８００℃で行う。本発明に
おいては、ゾル粒子が均一に分散された状態でゲル化さ
れ、ゲル中の粒子は個々の粒子間に有機増粘剤が介在し
ており、焼成によって、先ず水が蒸発し、次に該有機増
粘剤が燃え尽きるので、二次凝集の少ない微粉末を容易
に得ることができる。In the present invention, the gel in which the inorganic particles are uniformly dispersed is fired to recover the inorganic particles as fine powder. Firing is usually 500 to 12 at a temperature of 500 ° C or higher.
The temperature is 00 ° C., preferably 600 to 800 ° C. In the present invention, the sol particles are gelled in a uniformly dispersed state, the particles in the gel intercalate the organic thickener between the individual particles, by firing, first water is evaporated, then Since the organic thickener burns out, a fine powder with less secondary aggregation can be easily obtained.
【００１０】次に、実施例によって本発明をさらに詳し
く説明するが、これらは本発明を限定するものではな
い。Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention.
実施例１
ビーカーにTiO2として重量基準で５％の濃度の薄片状の
チタニアゾル（一次粒子の寸法：長軸の長さ５μｍ、短
軸の長さ４μｍ、厚み０．００１μｍ、分散安定剤とし
て３．６重量％のアミノメチルプロパノールを含有）を
入れ、この中にステアリン酸をチタニアに対して体積基
準で１００％添加し、攪拌してゲル化させた後ルツボに
移し、電気炉に入れ、６５０℃で１時間焼成して本発明
の薄片状二酸化チタン微粉末を得た。このものの電子顕
微鏡写真を図１として示す。図１より、二次凝集の少な
い厚み３０ｎｍ前後の薄片状酸化チタン粒子が得られた
ことがわかる。この微粉末を、手の甲に少量とってのば
してみたところ、肌でののびは良好であった。Example 1 Flake-shaped titania sol having a concentration of 5% by weight as TiO 2 in a beaker (dimensions of primary particles: major axis length 5 μm, minor axis length 4 μm, thickness 0.001 μm, 3 as a dispersion stabilizer) (Containing 6% by weight of aminomethyl propanol), stearic acid was added thereto in an amount of 100% by volume based on titania, stirred and gelled, then transferred to a crucible and placed in an electric furnace for 650 The flaky titanium dioxide fine powder of the present invention was obtained by calcining at 1 ° C for 1 hour. An electron micrograph of this product is shown in FIG. It can be seen from FIG. 1 that flaky titanium oxide particles having a thickness of around 30 nm with less secondary aggregation were obtained. When a small amount of this fine powder was spread on the back of the hand, it spread well on the skin.
【００１１】実施例２
上記実施例１において、増粘剤としてステアリン酸に代
えてステアリルアミンをチタニアに対して体積基準で１
００％添加すること以外は同様にして本発明の薄片状二
酸化チタン微粉末を得た。この微粉末は、実施例１と同
様に肌でののびは良好であった。Example 2 In the above Example 1, stearylamine was used in place of stearic acid as a thickening agent in an amount of 1 by volume based on titania.
The flaky titanium dioxide fine powder of the present invention was obtained in the same manner except that the addition of 00% was performed. As with Example 1, this fine powder had good spreadability on the skin.
【００１２】実施例３
上記実施例１において、５００℃で１時間焼成すること
以外は同様にして本発明の薄片状二酸化チタン微粉末を
得た。この微粉末は、実施例１と同様に肌でののびは良
好であった。Example 3 A flaky titanium dioxide fine powder of the present invention was obtained in the same manner as in Example 1 except that the firing was carried out at 500 ° C. for 1 hour. As with Example 1, this fine powder had good spreadability on the skin.
【００１３】実施例４
上記実施例２において薄片状チタニアゾルに代えて粒状
チタニアゾル（一次粒子の寸法：平均粒形３０ｎｍ、分
散安定剤として塩酸を含有）を用いたこと以外は同様に
して本発明の粒状二酸化チタン微粉末を得た。このもの
の電子顕微鏡写真を図２として示す。図２より、二次凝
集の少ない３０ｎｍ前後の二酸化チタン粒子が得られた
ことがわかる。また、実施例１と同様に、肌でののびは
良好であった。Example 4 In the same manner as in the above Example 2, except that granular titania sol (size of primary particles: average particle size: 30 nm, containing hydrochloric acid as a dispersion stabilizer) was used in place of the flaky titania sol. Granular titanium dioxide fine powder was obtained. An electron micrograph of this product is shown in FIG. From FIG. 2, it can be seen that titanium dioxide particles with a secondary aggregation of around 30 nm were obtained. Further, as in Example 1, the spreadability on the skin was good.
【００１４】比較例１
上記実施例１で使用した薄片状のチタニアゾルを６５０
℃で１時間乾燥、焼成した後、コロプレックスミルを用
いて粉砕して、比較試料とした。このものの電子顕微鏡
写真を図３として示す。図３より、厚み３００ｎｍ前後
の板状粒子が観られることから、薄片状チタニアゾル粒
子が重なる様に二次凝集して焼結したことがわかる。こ
の粉末について、実施例１と同様にして、肌でのびを調
べたところ、ザラツキがあって、のびは悪かった。Comparative Example 1 The flaky titania sol used in Example 1 above was 650.
After drying and firing at 1 ° C. for 1 hour, it was crushed using a coroplex mill to obtain a comparative sample. An electron micrograph of this product is shown in FIG. From FIG. 3, it can be seen that since plate-like particles having a thickness of about 300 nm are seen, the flaky titania sol particles are secondarily aggregated and sintered so as to overlap with each other. When this powder was examined for spreadability on the skin in the same manner as in Example 1, there was graininess and spreadability was poor.
【００１５】[0015]
【発明の効果】本発明においては、無機酸化物ゾル中に
有機増粘剤を添加してゲル化することにより、無機物粒
子間に該増粘剤を介在させてゲル中で無機物粒子を均一
に安定して存在させ、次に焼成することにより、先ず水
を蒸発させ、次に該増粘剤を燃焼させるので、無機物粒
子は二次凝集の少ない微粉末として回収することができ
る。INDUSTRIAL APPLICABILITY In the present invention, an organic thickener is added to an inorganic oxide sol to form a gel, and the thickener is interposed between the inorganic particles so that the inorganic particles are uniformly dispersed in the gel. Since the water is first evaporated and then the thickener is burned by being stably present and then calcined, the inorganic particles can be recovered as a fine powder with less secondary aggregation.
【図１】本発明の方法により得た薄片状酸化チタン粉末
の走査型電子顕微鏡写真を示す。FIG. 1 shows a scanning electron micrograph of flaky titanium oxide powder obtained by the method of the present invention.
【図２】本発明の方法により得た酸化チタン粉末の走査
型電子顕微鏡写真を示す。FIG. 2 shows a scanning electron micrograph of titanium oxide powder obtained by the method of the present invention.
【図３】薄片状チタニアゾルをそのまま焼成して得た板
状酸化チタン粉末の走査型電子顕微鏡写真を示す。FIG. 3 shows a scanning electron micrograph of a plate-shaped titanium oxide powder obtained by directly firing a flaky titania sol.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平８−12961（ＪＰ，Ａ) 特開 平１−145328（ＪＰ，Ａ) 特開 平５−139703（ＪＰ，Ａ) 特公 平２−33644（ＪＰ，Ｂ２) (58)調査した分野(Int.Cl.7，ＤＢ名) C01B 13/14 C01G 23/04 ＣＡ（ＳＴＮ)─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-12961 (JP, A) JP-A-1-145328 (JP, A) JP-A-5-139703 (JP, A) JP-B-2- 33644 (JP, B2) (58) Fields investigated (Int.Cl. 7 , DB name) C01B 13/14 C01G 23/04 CA (STN)
Claims (8)
て、無機酸化物ゾルをゲル化し、次いで、得られたゲル
を５００℃以上の温度で焼成して、ゲルに含まれる有機
増粘剤を燃焼させることを特徴とする無機酸化物微粉末
の製造方法。1. An organic thickener is added to an inorganic oxide sol.
To gel the inorganic oxide sol, and then the resulting gel
The fired at 500 ° C. or higher temperatures, the organic contained in the gel
A method for producing an inorganic oxide fine powder, which comprises burning a thickener .
鉛、酸化鉄、酸化珪素或いは酸化アルミニウムのゾルで
ある請求項１に記載の無機酸化物微粉末の製造方法。2. The method for producing fine inorganic oxide powder according to claim 1, wherein the inorganic oxide sol is a sol of titanium oxide, zinc oxide, iron oxide, silicon oxide or aluminum oxide.
亜鉛、水酸化鉄、水酸化珪素或いは水酸化アルミニウム
のゾルである請求項１に記載の無機酸化物微粉末の製造
方法。3. The method for producing fine inorganic oxide powder according to claim 1, wherein the inorganic oxide sol is a sol of titanium hydroxide, zinc hydroxide, iron hydroxide, silicon hydroxide or aluminum hydroxide.
状酸化チタン、針状酸化チタン或いは紡錘状酸化チタン
のゾルである請求項１に記載の無機酸化物微粉末の製造
方法。4. The method for producing fine inorganic oxide powder according to claim 1, wherein the inorganic oxide sol is a sol of flaky titanium oxide, granular titanium oxide, acicular titanium oxide or spindle-shaped titanium oxide.
粒状水酸化チタン、針状水酸化チタン或いは紡錘状水酸
化チタンのゾルである請求項１に記載の無機酸化物微粉
末の製造方法。5. A flaky titanium hydroxide as the inorganic oxide sol,
The method for producing fine inorganic oxide powder according to claim 1, which is a sol of granular titanium hydroxide, acicular titanium hydroxide or spindle-shaped titanium hydroxide.
アミン、ゼラチン、ポリビニルアルコール、アルキルセ
ルロース化合物または高分子多糖類である請求項１に記
載の無機酸化物微粉末の製造方法。6. The organic thickener is stearic acid or stearyl.
Amine, gelatin, polyvinyl alcohol, alkyl
The method for producing an inorganic oxide fine powder according to claim 1, which is a lulose compound or a high molecular polysaccharide .
求項１に記載の無機酸化物微粉末の製造方法。7. The method for producing an inorganic oxide fine powder according to claim 1, which is fired at a temperature of 500 to 1200 ° C.
で５０〜１０００％添加する請求項１に記載の無機酸化
物微粉末の製造方法。8. The method for producing an inorganic oxide fine powder according to claim 1, wherein the organic thickener is added in an amount of 50 to 1000% by volume with respect to the inorganic oxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25426997A JP3373767B2 (en) | 1997-09-02 | 1997-09-02 | Method for producing inorganic oxide fine powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25426997A JP3373767B2 (en) | 1997-09-02 | 1997-09-02 | Method for producing inorganic oxide fine powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1179712A JPH1179712A (en) | 1999-03-23 |
| JP3373767B2 true JP3373767B2 (en) | 2003-02-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25426997A Expired - Lifetime JP3373767B2 (en) | 1997-09-02 | 1997-09-02 | Method for producing inorganic oxide fine powder |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CA2643730C (en) | 2006-03-14 | 2013-09-24 | Ishihara Sangyo Kaisha, Ltd. | Visible light-responsive photocatalyst, method for producing same, photocatalyst coating agent using same, and photocatalyst dispersion |
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- 1997-09-02 JP JP25426997A patent/JP3373767B2/en not_active Expired - Lifetime
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| Publication number | Publication date |
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| JPH1179712A (en) | 1999-03-23 |
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