JP2002249315A - THIN-CHIP FOAM alpha-ALUMINA PARTICLE AND METHOD FOR PRODUCING THE SAME - Google Patents

THIN-CHIP FOAM alpha-ALUMINA PARTICLE AND METHOD FOR PRODUCING THE SAME

Info

Publication number
JP2002249315A
JP2002249315A JP2001040237A JP2001040237A JP2002249315A JP 2002249315 A JP2002249315 A JP 2002249315A JP 2001040237 A JP2001040237 A JP 2001040237A JP 2001040237 A JP2001040237 A JP 2001040237A JP 2002249315 A JP2002249315 A JP 2002249315A
Authority
JP
Japan
Prior art keywords
particles
alumina
flaky
particle size
mol
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
Application number
JP2001040237A
Other languages
Japanese (ja)
Inventor
Ryuichi Shito
隆一 紫藤
Yushi Fukuda
雄史 福田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
YKK Corp
Original Assignee
YKK Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by YKK Corp filed Critical YKK Corp
Priority to JP2001040237A priority Critical patent/JP2002249315A/en
Priority to EP01109347A priority patent/EP1148028A3/en
Priority to US09/834,651 priority patent/US7067157B2/en
Priority to KR10-2001-0044963A priority patent/KR100451589B1/en
Publication of JP2002249315A publication Critical patent/JP2002249315A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/021—After-treatment of oxides or hydroxides
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00—Cosmetics or similar toiletry preparations
    • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
    • A61K8/26—Aluminium; Compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/20—Particle morphology extending in two dimensions, e.g. plate-like
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/54—Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Cosmetics (AREA)
  • Pigments, Carbon Blacks, Or Wood Stains (AREA)

Abstract

PROBLEM TO BE SOLVED: To synthesize a thin-chip form particle which is flat in shape and capable of maintaining a stable dispersing state in an aqueous solvent while maintaining a uniform shape and dispersing property of a single particle which are characteristics of an alumina particle obtainable by hydrothermal synthesis. SOLUTION: The thin-chip form α-alumina particle has an average particle diameter of 0.5 to 25 μm, a flat shape with aspecto ratio (average particle diameter/thickness of particle) of 50 to 2,000 (without including 50). A phosphoric compound is present in an amount of 0.2-5.0 wt.% as P2 P5 with respect to the alumina particle. An alumina hydrate or an alumina gel is a starting material having an average diameter of <=2 μm and a maximum diameter of <=5 μm, and an aqueous slurry is hydrothermally synthesized by adding phosphoric ions of 1.0×10<-3> -1.0×10<-1> mol to 1 mol of the alumina hydrate or the alumina gel.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、アスペクト比が極
めて大きく、又、ゴム・プラスチック用フィラー及び顔
料、塗工材として樹脂に混練する際に分散性が良く、さ
らに、精密研磨用スラリーや化粧用途として水系溶媒に
添加した際にも容易に単一粒子として分散し、安定分散
状態を維持するため、粒子の配向性が良好な薄片状のα
−アルミナ粒子および当該粒子の製造法に関する。BACKGROUND OF THE INVENTION The present invention has an extremely large aspect ratio, has good dispersibility when kneaded with a resin as a filler or pigment for rubber or plastic, or a coating material, and further has a slurry for fine polishing or a cosmetic. Even when added to an aqueous solvent as an application, it is easily dispersed as a single particle and maintains a stable dispersion state, so that the orientation of the particles is good and the flaky α
It relates to alumina particles and to a method for producing said particles.

【０００２】[0002]

【従来の技術】バイヤー法などで得られる水酸化アルミ
ニウムやアルミニウムイオンの中和処理によって得られ
るアルミナゲルを出発物質として板状アルミナ粒子を製
造する方法として、鉱化剤を添加するか焼法等（特公昭
３５−６９７７号公報）がある。しかし、当処理粉体中
には凝集した板状粒子が多く存在し、樹脂成分中に添加
しても樹脂の機械的強度向上や塗料化したときの光沢感
が得られにくい問題があった。2. Description of the Related Art As a method for producing plate-like alumina particles starting from an alumina gel obtained by a neutralization treatment of aluminum hydroxide or aluminum ions obtained by a Bayer method or the like, a calcining method by adding a mineralizer, etc. (Japanese Patent Publication No. 35-6977). However, there are many agglomerated plate-like particles in the treated powder, and there is a problem that even when added to the resin component, it is difficult to improve the mechanical strength of the resin or to obtain a glossy feeling when formed into a paint.

【０００３】そこで水酸化アルミニウムを水性スラリー
にし、オートクレーブ中で水熱処理を行って、粒子形状
が均一で分散性の良い板状粒子を合成する方法が確立さ
れて、得られた粒子の樹脂への混練時における分散性は
向上した（特開平５−１７１３２号公報等）。しかしか
かるアルミナ粉体でも、精密研磨用途や化粧品用途とし
て板状粒子を水系溶媒に添加しスラリーとして使用する
場合、溶媒内で分散が進行しにくかったり分散後再凝集
を起こしやすかったりして、結果として被研磨品の表面
粗さを小さくし難かったり、化粧品粉体の進展性や塗布
後の光輝性が十分に得られにくい等の問題点を抱えてい
た。[0003] Therefore, a method of synthesizing plate-like particles having a uniform particle shape and good dispersibility by making aluminum hydroxide into an aqueous slurry and performing a hydrothermal treatment in an autoclave has been established. The dispersibility at the time of kneading was improved (JP-A-5-17132). However, even with such alumina powder, when plate-like particles are added to an aqueous solvent and used as a slurry for precision polishing or cosmetic use, dispersion in the solvent is difficult to proceed or re-agglomeration after dispersion is likely to occur. There are problems that it is difficult to reduce the surface roughness of the article to be polished, and that it is difficult to sufficiently obtain the spreadability of the cosmetic powder and the glittering property after application.

【０００４】[0004]

【発明が解決しようとする課題】樹脂や各種溶媒に混
合、混練する際、製品として成形体の緻密化、機械的物
性の向上、また塗膜およびスラリーの安定性、塗布後の
乾燥体の光輝性の向上を図るには、樹脂成分や各種溶媒
中の薄片状粒子に高い分散性が必要とされるが、そのた
めには凝集粒子の削減、粒子表面と分散媒体との親和
性、粒子の表面荷電状態が全て良好でないと実現できな
い。When mixed and kneaded with a resin or various solvents, the molded product is densified, the mechanical properties are improved, the stability of the coating film and slurry is maintained, and the brightness of the dried product after application is improved. In order to improve the dispersibility, high dispersibility is required for the flaky particles in the resin component and various solvents. To achieve this, the reduction of agglomerated particles, the affinity between the particle surface and the dispersion medium, the surface of the particles This cannot be achieved unless the charge states are all good.

【０００５】そこで、本発明の目的は水熱合成法で得ら
れるアルミナ粒子の特徴である均一な形状、単一粒子の
分散性を維持しながら、扁平で且つ水系溶媒に対して安
定した分散状態を維持できる配向性の良好な薄片状粒子
を合成することにある。Accordingly, an object of the present invention is to provide a flat and stable dispersion state in an aqueous solvent while maintaining a uniform shape and dispersibility of single particles, which are characteristics of alumina particles obtained by a hydrothermal synthesis method. The present invention is to synthesize flaky particles having good orientation and capable of maintaining the following.

【０００６】[0006]

【課題を解決するための手段】本発明は、（１）平均粒
径０．５〜２５μｍ、平均粒径／粒子厚みで表されるア
スペクト比が５０（５０は含まず）〜２０００の扁平形
状からなることを特徴とする薄片状α−アルミナ粒子、
及び、（２）リン酸化合物がアルミナ粒子に対し、酸化
物換算にてＰ2Ｏ5として０．２〜５．０ｗｔ％存在して
なる前記（１）記載の薄片状α−アルミナ粒子、（３）
前記粒子のゼータ電位が０を示す等電位点が、ｐＨ２〜
５を示す前記（１）又は（２）記載の薄片状α−アルミ
ナ粒子、に係るものである。According to the present invention, there is provided (1) a flat shape having an average particle diameter of 0.5 to 25 μm and an aspect ratio expressed by average particle diameter / particle thickness of 50 (not including 50) to 2000. Flaky α-alumina particles, characterized by comprising
And (2) the flaky α-alumina particles according to (1), wherein the phosphate compound is present in the alumina particles in an amount of 0.2 to 5.0 wt% as P 2 O 5 in terms of oxide. 3)
The equipotential point where the zeta potential of the particles indicates 0 is pH 2
5 according to the above (1) or (2).

【０００７】そしてその製造法として、（４）アルミナ
水和物及びアルミナゲルを出発原料として、原料の平均
粒径は２μｍ以下、最大粒径を５μｍ以内とし、更にア
ルミナ水和物またはアルミナゲルを１モルに対し、リン
酸イオンを１．０×１０-3〜１．０×１０-1モル添加し
て水系スラリーを水熱合成することを特徴とする前記
（１）、（２）又は（３）記載の薄片状α−アルミナ粒
子の製造方法、並びに、（５）アルミナ水和物及びアル
ミナゲルを出発原料として、リン酸イオンの他に種晶と
して粒径１μｍ未満、比表面積５ｍ2／ｇ以上のα−ア
ルミナ粒子を原料１モルに対して１．０×１０-6〜５．
０×１０-3モル添加して水熱合成し、薄片状粒子の粒径
を制御することを特徴とする前記（４）記載の薄片状α
−アルミナ粒子の製造方法、に係るものである。[0007] The production method is as follows: (4) Starting from alumina hydrate and alumina gel, the average particle diameter of the raw material is set to 2 µm or less, the maximum particle diameter is set to 5 µm or less. (1), (2) or (1), wherein the aqueous slurry is hydrothermally synthesized by adding 1.0 × 10 −3 to 1.0 × 10 −1 mol of phosphate ion per 1 mol. 3) The method for producing flaky α-alumina particles as described in (3), and (5) Starting from alumina hydrate and alumina gel, having a particle size of less than 1 μm and a specific surface area of 5 m 2 / g of the α-alumina particles in an amount of 1.0 × 10 −6 to 1 mol per mol of the raw material.
0.times.10.sup.-3 mol is added and hydrothermally synthesized to control the particle size of the flaky particles.
-A method for producing alumina particles.

【０００８】本発明において製造される薄片状アルミナ
の形状は図１のようになる。従来の水熱合成法で合成さ
れるα−アルミナ粒子は図２のように（ｎ，ｃ，ａ，
ｒ）等の面にて構成されるが、本発明の薄片状粒子は
（ｎ，ｃ）面でのみ構成される。ここで言う粒子径とは
ｃ面の長軸径、アスペクト比は（ｃ面の長軸径）／（２
つのｃ面間で表される厚みＬ）で表される。算出法は電
子顕微鏡で任意に選んだ１０枚の粒子の平均を取る。The shape of the flaky alumina produced in the present invention is as shown in FIG. Α-alumina particles synthesized by a conventional hydrothermal synthesis method are shown in FIG. 2 as (n, c, a,
r), the flaky particles of the present invention are composed only of the (n, c) plane. The particle diameter referred to here is the major axis diameter of the c plane, and the aspect ratio is (major axis diameter of the c plane) / (2
Thickness c) between the two c-planes. The calculation method is to take an average of 10 particles arbitrarily selected by an electron microscope.

【０００９】粒子径は０．５μｍ〜２５μｍ、より好ま
しくは２μｍ〜２０μｍを有するのに対し、厚みＬが薄
いため、アスペクト比は５０（５０は含まず）〜２００
０、好ましくは５０（５０は含まず）〜２００、さらに
好ましくは５５〜２００、さらには６０〜２００とな
る。厚みＬは、前記条件を満たす範囲であるが、特には
０．０１μｍ〜０．２μｍであることが好ましい。Although the particle diameter is 0.5 μm to 25 μm, more preferably 2 μm to 20 μm, the aspect ratio is 50 (excluding 50) to 200 due to the small thickness L.
0, preferably 50 (not including 50) to 200, more preferably 55 to 200, furthermore 60 to 200. The thickness L is in a range that satisfies the above condition, but is particularly preferably 0.01 μm to 0.2 μm.

【００１０】本発明の目的を達成するα−アルミナ粒子
とするには、平均粒径及びアスペクト比が重要であり、
上記の範囲とすることが必要であり、より効果を高める
には、特に粒子の配向性を高めるためには、上記好まし
い範囲とすることが有効である。In order to obtain α-alumina particles for achieving the object of the present invention, the average particle size and the aspect ratio are important.
It is necessary to be within the above-mentioned range, and it is effective to make the above-mentioned preferable range in order to further enhance the effect, particularly to enhance the orientation of the particles.

【００１１】本発明において原料である水酸化アルミニ
ウム、アルミナ水和物は特に限定されるものではなく、
バイヤー法工程より得られたギブサイト型水酸化アルミ
ニウムやアモルファス状のものが使用できる。In the present invention, the raw materials of aluminum hydroxide and alumina hydrate are not particularly limited.
Gibbsite-type aluminum hydroxide obtained from the Bayer process and amorphous materials can be used.

【００１２】これらの原料はあらかじめ粒度調整を行
い、平均粒径は２μｍ以下、最大粒径を５μｍ以内、好
ましくは平均粒径は０．２μｍ〜１．５μｍにするとよ
い。原料の微細化（平均粒径＜０．２μｍ）は合成後の
粒子径が小さくなりすぎ、アスペクト比は相対的に小さ
くなる。さらに粒子径が小さくなると緻密な凝集粒子が
発生し、樹脂や水系スラリーに添加したとき単一粒子へ
分散が進まない。最大粒径５μｍを超える原料を使用し
た場合、合成後に薄片状粒子が強固に凝集した二次粒子
が発生し分散性は向上しない。The particle size of these raw materials is adjusted in advance, and the average particle size is 2 μm or less, the maximum particle size is 5 μm or less, preferably the average particle size is 0.2 μm to 1.5 μm. Finer raw materials (average particle size <0.2 μm) result in too small a particle size after synthesis and a relatively small aspect ratio. When the particle size is further reduced, dense aggregated particles are generated, and when added to a resin or an aqueous slurry, dispersion to single particles does not proceed. When a raw material having a maximum particle size of more than 5 μm is used, secondary particles in which flaky particles are strongly aggregated after the synthesis are generated, and the dispersibility is not improved.

【００１３】原料粉体の粒度調整方法は、ボールミル、
媒体攪拌ミルが主に用いられるが、これに限定されるも
のではない。The method for adjusting the particle size of the raw material powder is a ball mill,
A medium stirring mill is mainly used, but is not limited to this.

【００１４】本発明は、上記原料と水を混合したスラリ
ーを水熱合成する。このスラリーの濃度は、１ｗｔ％〜
６０ｗｔ％、好ましくは２０ｗｔ％〜５０ｗｔ％であ
る。６０ｗｔ％を超えると凝集粒子が発生する傾向を示
すためである。In the present invention, a slurry obtained by mixing the above-mentioned raw materials and water is hydrothermally synthesized. The concentration of this slurry is 1wt% ~
It is 60 wt%, preferably 20 wt% to 50 wt%. If the content exceeds 60% by weight, a tendency to generate aggregated particles is exhibited.

【００１５】薄片状粒子の厚さを薄くし、アスペクト比
を大きくするには、リン酸イオンを１．０×１０-3〜
１．０×１０-1の範囲内で、リン酸添加量を増やすこと
が有効である。リン酸イオンを添加する場合、オルトリ
ン酸、メタリン酸、ピロリン酸の水溶液を添加するが必
ずしもこれに限られるものではない。ホスホン酸、ホス
フィン酸や、リン酸二水素ナトリウム、リン酸一水素ア
ンモニウム等のリン酸塩であっても構わない。原料１モ
ルに対しリン酸添加量が１．０×１０-3モル未満では合
成後の粒子は厚みがありアスペクト比が５０を超える薄
片状粒子が合成できにくくなる。原料１モルに対しリン
酸添加量が１．０×１０-1モルを超えると合成後に薄片
状粒子が凝集した二次粒子が多くなってしまう。In order to reduce the thickness of the flaky particles and increase the aspect ratio, phosphate ions must be added in an amount of 1.0 × 10 −3 to 1.0 × 10 −3 .
It is effective to increase the amount of phosphoric acid added within the range of 1.0 × 10 −1 . When adding phosphate ions, an aqueous solution of orthophosphoric acid, metaphosphoric acid, or pyrophosphoric acid is added, but is not necessarily limited thereto. Phosphonic acid, phosphinic acid, and phosphates such as sodium dihydrogen phosphate and ammonium monohydrogen phosphate may be used. If the amount of phosphoric acid added is less than 1.0 × 10 −3 mol per mol of the raw material, the synthesized particles have a large thickness, and it is difficult to synthesize flaky particles having an aspect ratio exceeding 50. If the amount of phosphoric acid exceeds 1.0 × 10 −1 mol per mol of the raw material, the number of secondary particles in which flaky particles are aggregated after the synthesis increases.

【００１６】薄片状粒子の平均粒径を制御するには原料
と水を混合したスラリーに種晶として粒径１μｍ未満、
比表面積５ｍ2／ｇ以上のα−アルミナ粒子を添加する
方法が有効である。種晶は超音波等で分散させてスラリ
ーの中に添加するのが望ましい。この条件で種晶を添加
すると、添加量の増量に伴って合成後の薄片状アルミナ
粒子を微細化することができる。粒径１μｍ以上の種晶
を添加すると、合成後に厚みが０．２μｍ以上ある粒子
が増え、薄片状粒子はできにくくなる。比表面積が５ｍ
2／ｇ未満の種晶では粒径の制御は難しい。添加量は原
料１モルに対して１．０×１０-6〜５．０×１０-3モル
が好ましい。５．０×１０-3モル以上添加しても、粒径
を微細化させる効果は小さくなってしまう。上記の種晶
添加により、薄片状アルミナの平均粒径を０．５〜２５
μｍの間で制御することができる。In order to control the average particle size of the flaky particles, a slurry in which a raw material and water are mixed is used as a seed crystal to have a particle size of less than 1 μm,
It is effective to add α-alumina particles having a specific surface area of 5 m 2 / g or more. The seed crystal is desirably dispersed in an ultrasonic wave or the like and added to the slurry. When the seed crystal is added under these conditions, the flaky alumina particles after synthesis can be made finer as the amount of addition increases. When a seed crystal having a particle diameter of 1 μm or more is added, particles having a thickness of 0.2 μm or more after synthesis increase, and it becomes difficult to form flaky particles. Specific surface area is 5m
With a seed crystal of less than 2 / g, it is difficult to control the particle size. The addition amount is preferably from 1.0 × 10 −6 to 5.0 × 10 −3 mol per 1 mol of the raw material. Even if added in an amount of 5.0 × 10 −3 mol or more, the effect of reducing the particle size is reduced. By the addition of the seed crystal, the average particle size of the flaky alumina is 0.5 to 25.
It can be controlled between μm.

【００１７】水熱合成の反応温度は４００℃以上であ
り、好ましくは４５０℃以上である。スラリーの最高温
度が４００〜４５０℃になる場合、α−アルミナ化の反
応を完了させるために昇温後、温度保持時間を２４時間
以上要する。合成圧力は１０ＭＰａ〜２５ＭＰａ、好ま
しくは１５ＭＰａ〜２０ＭＰａとする。合成温度・圧力
の関係はＡｌ2Ｏ3−Ｈ2Ｏ系状態図でα−Ａｌ2Ｏ3（コ
ランダム）の範囲でなければならない。合成圧力１０Ｍ
Ｐａ以上を要するのは、この範囲を外れた低圧下では、
薄片状粒子の他に粒状形をした粒子の混在状態で合成さ
れ、粒子径のばらつきが大きくなる。また合成圧力２０
ＭＰａ以上になると粒子は厚肉化の傾向を示し、２５Ｍ
Ｐａを超えると厚肉化しすぎるので好ましくない。The reaction temperature of the hydrothermal synthesis is 400 ° C. or higher, preferably 450 ° C. or higher. When the maximum temperature of the slurry reaches 400 to 450 ° C., a temperature holding time of 24 hours or more is required after the temperature is raised to complete the α-aluminaization reaction. The synthesis pressure is 10 MPa to 25 MPa, preferably 15 MPa to 20 MPa. The relationship between the synthesis temperature and the pressure must be within the range of α-Al 2 O 3 (corundum) in the Al 2 O 3 —H 2 O phase diagram. Synthetic pressure 10M
The reason for requiring Pa or more is that under low pressure outside this range,
The particles are synthesized in a mixed state of granular particles in addition to the flaky particles, and the dispersion of the particle diameter becomes large. In addition, the synthesis pressure 20
When the pressure exceeds MPa, the particles show a tendency to thicken,
If it exceeds Pa, it is not preferable because it becomes too thick.

【００１８】[0018]

【作用】本発明により、平均粒径０．５μｍ〜２５μ
ｍ、アスペクト比５０（５０は含まず）〜２０００であ
る薄片状α−アルミナ粒子を合成することができる。そ
の際、種晶の添加量を規定することによって平均粒子径
が上記範囲にて制御できる。According to the present invention, the average particle size is 0.5 μm to 25 μm.
m, and flaky α-alumina particles having an aspect ratio of 50 (not including 50) to 2000 can be synthesized. At this time, the average particle diameter can be controlled in the above range by defining the amount of the seed crystal to be added.

【００１９】この粒子は凝集粒子が少なく、フィラーと
してプラスチック及びゴムの中に混練したとき、薄片状
粒子は良分散状態となる。さらに粒子の扁平性が高いの
で、この樹脂とフィラーの複合体をシート状に成形した
時の成形体の引張強度、スティフネス等の機械的強度が
向上する。また、成形後の温度低下に伴う収縮率も低下
する。These particles have a small amount of agglomerated particles, and when kneaded in a plastic or rubber as a filler, the flaky particles are in a good dispersion state. Further, since the flatness of the particles is high, the mechanical strength such as the tensile strength and the stiffness of the molded body when the composite of the resin and the filler is molded into a sheet is improved. In addition, the shrinkage rate accompanying the temperature decrease after molding also decreases.

【００２０】また、塗料用顔料や塗工剤として使用した
場合、塗装後薄片状粒子は塗膜中に平行に配向すること
により、塗膜の劣化を防ぎ、また塗膜内部への腐食物質
の侵入防止効果が期待できる。塗膜表面への粒子の突出
は確認されないことから、優れた表面平滑性を持ち、光
沢性を示す塗膜とすることができる。In addition, when used as a paint pigment or a coating agent, the flaky particles after coating are oriented in parallel in the coating film to prevent deterioration of the coating film and to prevent corrosive substances from entering the inside of the coating film. Intrusion prevention effect can be expected. Since no protrusion of particles to the surface of the coating film is confirmed, a coating film having excellent surface smoothness and exhibiting gloss can be obtained.

【００２１】さらに、この粒子の特徴として、水系溶媒
との親和性も良好であり、攪拌等の簡単な分散操作で安
定的な単一粒子の分散状態を維持することが可能にな
る。ゆえに、精密研磨用スラリーや化粧用途として水系
溶媒に分散させて使用した場合、非研磨物の表面平滑性
の向上や液体化粧品の安定性、進展性向上が期待でき
る。水系溶媒中で本粒子の分散性が良好な理由は定かで
はないが、最も重要な要因としては、α−アルミナ粒子
の薄片状形態にあり、上記平均粒子径であり、アスペク
ト比を有することが重要である。粒子の表面にリン酸イ
オンが存在し、粒子表面が若干帯電して粒子間に斥力が
働くことが重要な要因の一つと推定される。さらに、ゼ
ータ電位が０になる等電位点がｐＨ２〜５にあることに
より、中性の化粧品中でも、安定に分散状態を維持する
ことが可能になる重要な要因の一つと推定される。Further, as a characteristic of these particles, they have a good affinity for an aqueous solvent and can maintain a stable single particle dispersion state by a simple dispersion operation such as stirring. Therefore, when it is used after being dispersed in an aqueous solvent as a slurry for precision polishing or as a cosmetic application, it can be expected to improve the surface smoothness of a non-abrasive and to improve the stability and progress of a liquid cosmetic. The reason why the dispersibility of the particles is good in the aqueous solvent is not clear, but the most important factor is that the α-alumina particles are in the form of flakes, the average particle diameter is the above, and the aspect ratio is is important. It is presumed that one of the important factors is that phosphate ions are present on the surface of the particles, the surface of the particles is slightly charged, and repulsion acts between the particles. Furthermore, since the equipotential point at which the zeta potential becomes 0 is at pH 2 to 5, it is presumed that this is one of the important factors that makes it possible to stably maintain a dispersed state even in neutral cosmetics.

【００２２】[0022]

【発明の実施の形態】以下、具体的な実施例について述
べる。 実施例１ バイヤー法にて得られたギブサイト型水酸化アルミニウ
ムを平均粒径１．１μｍに調整し、原料１モルに対しオ
ルトリン酸３．０×１０-3モル添加し、５０ｗｔ％濃度
の水系スラリーにしてから、合成温度６００℃、合成圧
力１５ＭＰａにて水熱合成を行い、水洗、乾燥後白色の
粉体を得た。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments will be described. Example 1 Gibbsite type aluminum hydroxide obtained by the Bayer method was adjusted to an average particle diameter of 1.1 μm, and 3.0 × 10 −3 mol of orthophosphoric acid was added to 1 mol of the raw material, and a 50 wt% aqueous slurry was added. After that, hydrothermal synthesis was performed at a synthesis temperature of 600 ° C. and a synthesis pressure of 15 MPa, washed with water and dried to obtain a white powder.

【００２３】粉体は平均粒径１２．０μｍ、平均厚み
０．１５μｍ、アスペクト比は８０の薄片状粒子であっ
た。蛍光Ｘ線による粉体中の組成分析の結果、酸化物換
算でＰ 2Ｏ5０．３ｗｔ％を含有していることが確認され
た。等電位点はｐＨ４．３にあった。The powder has an average particle size of 12.0 μm and an average thickness.
0.15 μm, flaky particles with an aspect ratio of 80
Was. As a result of composition analysis in powder by X-ray fluorescence,
By calculation TwoOFiveIt was confirmed to contain 0.3 wt%
Was. The isoelectric point was at pH 4.3.

【００２４】さらに粒子は、１）樹脂への添加、２）水
性溶媒への添加実験を行い分散性をそれぞれ評価した。The particles were further subjected to 1) addition to a resin and 2) addition to an aqueous solvent to evaluate their dispersibility.

【００２５】１）それぞれの粒子１００部に対し、アク
リルラッカー（水谷ペイント製）５０部、トルエン２０
部、メチルエチルケトン１０部を添加し、ホモジナイザ
ーにて（ｉｋａ製 ＬＲ−４１Ｂ，１０００ｒｐｍ）５
分間攪拌を行い、ガラス板上にこのスラリーを塗布後、
５０℃で１時間加熱乾燥し硬化した。1) For 100 parts of each particle, 50 parts of acrylic lacquer (manufactured by Mizutani Paint) and 20 parts of toluene
Parts, and 10 parts of methyl ethyl ketone, and the mixture was homogenized (LR-41B, manufactured by ika, 1000 rpm).
Stir for a minute, apply this slurry on a glass plate,
It was dried by heating at 50 ° C. for 1 hour.

【００２６】２）それぞれの粒子１００部に対し、純水
を４０部添加し、ホモジナイザーにて（ｉｋａ製 ＬＲ
−４１Ｂ，１０００ｒｐｍ）５分間攪拌を行い、ガラス
板上にこのスラリーを塗布後、１２０℃で３０秒間乾燥
させた。2) 40 parts of pure water was added to 100 parts of each particle, and a homogenizer (LR manufactured by ika) was used.
(−41B, 1000 rpm) for 5 minutes, the slurry was applied on a glass plate, and dried at 120 ° C. for 30 seconds.

【００２７】各々のガラス板上にある成形体をＸ線回折
分析し、Ｌｏｔｇｅｒｉｎｇ法により、粉体の配向度を
算出した。分散性が高い程配向度の数値は大きくなり、
１に近い値を取る。１）樹脂添加実験の配向度は０．９
１、２）水性溶媒添加実験の配向度は０．８４となっ
た。The compact on each glass plate was subjected to X-ray diffraction analysis, and the degree of powder orientation was calculated by Lotgering method. The higher the degree of dispersion, the larger the value of the degree of orientation,
Take a value close to one. 1) The degree of orientation in the resin addition experiment was 0.9.
1, 2) The degree of orientation in the aqueous solvent addition experiment was 0.84.

【００２８】実施例２ 上記実施例１において、原料１モルに対し、オルトリン
酸の添加量を１．０×１０-2モルに増量し、水熱合成を
行い白色の粉体を得た。Example 2 In Example 1, the amount of orthophosphoric acid was increased to 1.0 × 10 -2 mol per mol of the raw material, and hydrothermal synthesis was performed to obtain a white powder.

【００２９】粉体は、平均粒径１１．０μｍ、平均厚み
０．０７μｍ、アスペクト比は約１６０の薄片状粒子で
あった。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ5
０．９ｗｔ％を含有していることが確認された。等電位
点はｐＨ３．８にあった。１）樹脂添加実験の配向度は
０．９０、２）水性溶媒添加実験の配向度は０．８８と
なった。The powder was flaky particles having an average particle size of 11.0 μm, an average thickness of 0.07 μm, and an aspect ratio of about 160. As a result of analyzing the composition in the powder, it was found that P 2 O 5
It was confirmed that it contained 0.9 wt%. The isoelectric point was at pH 3.8. 1) The degree of orientation in the experiment for adding the resin was 0.90, and 2) the degree of orientation in the experiment for adding the aqueous solvent was 0.88.

【００３０】実施例３ 上記実施例２において、オルトリン酸の他、種晶として
粒径０．１μｍのα−アルミナ粒子（大明化学工業製：
ＴＭ−ＤＡＲ ＢＥＴ 比表面積１４ｍ2／ｇ）を原料
１モルに対し８．０×１０-6モル添加し、水系スラリー
にして水熱合成を行い白色の粉体を得た。Example 3 In Example 2, in addition to orthophosphoric acid, α-alumina particles having a particle size of 0.1 μm as seed crystals (manufactured by Daimei Chemical Co., Ltd .:
(TM-DAR BET specific surface area: 14 m 2 / g) was added in an amount of 8.0 × 10 −6 mol per 1 mol of the raw material, and the resulting slurry was subjected to hydrothermal synthesis to obtain a white powder.

【００３１】粉体は、平均粒径７．５μｍ、平均厚み
０．０５μｍ、アスペクト比は１５０の薄片状粒子であ
った。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ
5０．８ｗｔ％を含有していることが確認された。等電
位点はｐＨ４．１にあった。１）樹脂添加実験の配向度
は０．８８、２）水性溶媒添加実験の配向度は０．８２
となった。The powder was flaky particles having an average particle size of 7.5 μm, an average thickness of 0.05 μm, and an aspect ratio of 150. As a result of composition analysis in the powder, P 2 O
It was confirmed to contain 5 0.8 wt%. The isoelectric point was at pH 4.1. 1) The degree of orientation in the resin addition experiment was 0.88, and 2) The degree of orientation in the aqueous solvent addition experiment was 0.82.
It became.

【００３２】実施例４ 上記実施例２において、オルトリン酸の他、種晶として
粒径０．１μｍのα−アルミナ粒子（大明化学工業製：
ＴＭ−ＤＡＲ ＢＥＴ 比表面積１４ｍ2／ｇ）を原料
１モルに対し８．０×１０-5モル添加し、水系スラリー
にして水熱合成を行い白色の粉体を得た。Example 4 In Example 2, in addition to orthophosphoric acid, α-alumina particles having a particle size of 0.1 μm as seed crystals (manufactured by Daimei Chemical Co., Ltd .:
(TM-DAR BET specific surface area: 14 m 2 / g) was added in an amount of 8.0 × 10 −5 mol per mol of the raw material, and the resulting slurry was subjected to hydrothermal synthesis to obtain a white powder.

【００３３】粉体は、平均粒径４．８μｍ、平均厚み
０．０４μｍ、アスペクト比は１２０の薄片状粒子であ
った。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ
5０．８ｗｔ％を含有していることが確認された。等電
位点はｐＨ４．５にあった。１）樹脂添加実験の配向度
は０．８９、２）水性溶媒添加実験の配向度は０．８１
となった。The powder was flaky particles having an average particle size of 4.8 μm, an average thickness of 0.04 μm, and an aspect ratio of 120. As a result of composition analysis in the powder, P 2 O
It was confirmed to contain 5 0.8 wt%. The isoelectric point was at pH 4.5. 1) The degree of orientation in the resin addition experiment was 0.89. 2) The degree of orientation in the aqueous solvent addition experiment was 0.81.
It became.

【００３４】比較例１ 上記実施例１において、原料の平均粒径を４．０μｍに
調整して、オルトリン酸を添加せずに水系スラリーにし
て水熱合成を行い、水洗、乾燥後白色の粉体を得た。Comparative Example 1 In Example 1, the average particle size of the raw materials was adjusted to 4.0 μm, and a hydrothermal synthesis was performed using an aqueous slurry without adding orthophosphoric acid. I got a body.

【００３５】粉体は、平均粒径５．０μｍ、平均厚み
０．７５μｍ、アスペクト比は約７の板状粒子であっ
た。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ5は含
有されていないことが確認された。等電位点はｐＨ７．
９にあった。１）樹脂添加実験の配向度は０．４２、
２）水性溶媒添加実験の配向度は０．３９となった。The powder was plate-like particles having an average particle size of 5.0 μm, an average thickness of 0.75 μm, and an aspect ratio of about 7. As a result of composition analysis in the powder, it was confirmed that P 2 O 5 was not contained in terms of oxide. The isoelectric point is pH7.
9 1) The degree of orientation in the resin addition experiment was 0.42,
2) The degree of orientation in the aqueous solvent addition experiment was 0.39.

【００３６】比較例２ 上記実施例２において、種晶として粒径２．０μｍ、比
表面積１５ｍ2／ｇのα−アルミナ粒子を原料１モルに
対し８．０×１０-5モル添加し、水系スラリーにして水
熱合成を行い白色の粉体を得た。Comparative Example 2 In Example 2, 8.0 × 10 -5 mol of α-alumina particles having a particle size of 2.0 μm and a specific surface area of 15 m 2 / g were added as a seed crystal to 1 mol of the raw material, The slurry was subjected to hydrothermal synthesis to obtain a white powder.

【００３７】粉体は、平均粒径１０．５μｍ、平均厚み
０．３０μｍ、アスペクト比は３５の粒子であった。粉
体中の組成分析の結果、酸化物換算でＰ2Ｏ5０．８ｗｔ
％を含有していることが確認された。等電位点はｐＨ
３．７にあった。１）樹脂添加実験の配向度は０．６
０、２）水性溶媒添加実験の配向度は０．４３となっ
た。各種粉体の製造条件を表１、粉体の粒子形状、組
成、分散性を示す配向度を表２に示す。The powder had an average particle size of 10.5 μm, an average thickness of 0.30 μm, and an aspect ratio of 35. As a result of the composition analysis of the powder, P 2 O 5 0.8wt in terms of oxide
% Was confirmed to be contained. Equipotential point is pH
3.7. 1) The degree of orientation in the resin addition experiment was 0.6
0, 2) The degree of orientation in the aqueous solvent addition experiment was 0.43. Table 1 shows the production conditions of various powders, and Table 2 shows the degree of orientation indicating the particle shape, composition, and dispersibility of the powder.

【００３８】[0038]

【表１】 [Table 1]

【００３９】[0039]

【表２】 [Table 2]

【００４０】[0040]

【発明の効果】以上のように本発明の薄片状α−アルミ
ナ粒子の効果として、平均粒径０．５〜２５μｍ、アス
ペクト比５０（５０は含まず）〜２０００である薄片状
α−アルミナ粒子であり、単一粒子の分散性を維持しな
がら、扁平で且つ水系溶媒に対して安定した分散状態を
維持することができるため、粒子の配向性を向上させる
ことができる。As described above, as the effects of the flaky α-alumina particles of the present invention, the flaky α-alumina particles having an average particle size of 0.5 to 25 μm and an aspect ratio of 50 (not including 50) to 2,000. In addition, since a flat and stable dispersion state in an aqueous solvent can be maintained while maintaining the dispersibility of the single particles, the orientation of the particles can be improved.

【００４１】特に、粒子中に含まれるリン酸イオンの効
果により、樹脂中に混練する時だけでなく、水系溶媒に
添加させた際にもより容易に単一粒子に分散し高分散性
の特徴を発揮するアルミナ粒子を提供することができ
る。この粉体をフィラーとして混練したプラスチックや
ゴム等は、その優れた分散性により補強効果が得られ
る。また、塗料用顔料や塗工剤として各種溶媒に分散さ
せて使用した場合、塗料の粘度上昇が抑えられることに
より、流動性、塗工性が維持できる。塗装後、薄片状粒
子は塗膜中に平行に配向することにより、塗膜の劣化を
防ぎ、また塗膜内部への物質の侵入防止効果が期待でき
る。また表面の平滑性が高く、光沢性のある塗膜を得る
ことができる。さらに当粉体を使用した研磨用スラリー
は、被研磨物の表面平滑性を向上させることができ、化
粧品として当粉体を使用すると進展性の向上効果も発揮
することができる。また、本発明の薄片状α−アルミナ
粒子の製造方法によれば、上記優れた特性を有する薄片
状α−アルミナ粒子を容易に、さらに効率よく製造する
ことができる。In particular, due to the effect of phosphate ions contained in the particles, not only when kneading into the resin, but also when added to an aqueous solvent, the particles are more easily dispersed into single particles and have a characteristic of high dispersibility. Can be provided. Plastics, rubbers, and the like obtained by kneading this powder as a filler have a reinforcing effect due to their excellent dispersibility. In addition, when used as a paint pigment or a coating agent after being dispersed in various solvents, the increase in viscosity of the paint is suppressed, so that fluidity and coatability can be maintained. After coating, the flaky particles are oriented in parallel in the coating film, thereby preventing the coating film from deteriorating and preventing the substance from entering the inside of the coating film. Further, a glossy coating film having high surface smoothness can be obtained. Further, the polishing slurry using the powder can improve the surface smoothness of the object to be polished, and the use of the powder as a cosmetic can also exhibit the effect of improving the spreadability. Further, according to the method for producing flaky α-alumina particles of the present invention, flaky α-alumina particles having the above-mentioned excellent properties can be produced easily and more efficiently.

【図面の簡単な説明】[Brief description of the drawings]

【図１】図１は本発明により製造される薄片状粒子の形
状を表す模式図である。FIG. 1 is a schematic view showing the shape of a flaky particle produced according to the present invention.

【図２】従来の水熱合成法により作製される板状粒子の
形状を表す模式図である。FIG. 2 is a schematic diagram showing the shape of plate-like particles produced by a conventional hydrothermal synthesis method.

【手続補正書】[Procedure amendment]

【提出日】平成１３年４月１９日（２００１．４．１
９）[Submission date] April 19, 2001 (2001.4.1
9)

【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】全文[Correction target item name] Full text

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【書類名】 明細書[Document Name] Statement

【発明の名称】 薄片状α−アルミナ粒子及びその製
造方法Patent application title: Flaky α-alumina particles and method for producing the same

【特許請求の範囲】[Claims]

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、アスペクト比が極
めて大きく、又、ゴム・プラスチック用フィラー及び顔
料、塗工材として樹脂に混練する際に分散性が良く、さ
らに、精密研磨用スラリーや化粧用途として水系溶媒に
添加した際にも容易に単一粒子として分散し、安定分散
状態を維持するため、粒子の配向性が良好な薄片状のα
−アルミナ粒子および当該粒子の製造法に関する。BACKGROUND OF THE INVENTION The present invention has an extremely large aspect ratio, has good dispersibility when kneaded with a resin as a filler or pigment for rubber or plastic, or a coating material, and further has a slurry for fine polishing or a cosmetic. Even when added to an aqueous solvent as an application, it is easily dispersed as a single particle and maintains a stable dispersion state, so that the orientation of the particles is good and the flaky α
It relates to alumina particles and to a method for producing said particles.

【０００２】[0002]

【従来の技術】バイヤー法などで得られる水酸化アルミ
ニウムやアルミニウムイオンの中和処理によって得られ
るアルミナゲルを出発物質として板状アルミナ粒子を製
造する方法として、鉱化剤を添加するか焼法等（特公昭
３５−６９７７号公報）がある。しかし、当処理粉体中
には凝集した板状粒子が多く存在し、樹脂成分中に添加
しても樹脂の機械的強度向上や塗料化したときの光沢感
が得られにくい問題があった。2. Description of the Related Art As a method for producing plate-like alumina particles starting from an alumina gel obtained by a neutralization treatment of aluminum hydroxide or aluminum ions obtained by a Bayer method or the like, a calcining method by adding a mineralizer, etc. (Japanese Patent Publication No. 35-6977). However, there are many agglomerated plate-like particles in the treated powder, and there is a problem that even when added to the resin component, it is difficult to improve the mechanical strength of the resin or to obtain a glossy feeling when formed into a paint.

【０００３】そこで水酸化アルミニウムを水性スラリー
にし、オートクレーブ中で水熱処理を行って、粒子形状
が均一で分散性の良い板状粒子を合成する方法が確立さ
れて、得られた粒子の樹脂への混練時における分散性は
向上した（特開平５−１７１３２号公報等）。しかしか
かるアルミナ粉体でも、精密研磨用途や化粧品用途とし
て板状粒子を水系溶媒に添加しスラリーとして使用する
場合、溶媒内で分散が進行しにくかったり分散後再凝集
を起こしやすかったりして、結果として被研磨品の表面
粗さを小さくし難かったり、化粧品粉体の進展性や塗布
後の光輝性が十分に得られにくい等の問題点を抱えてい
た。[0003] Therefore, a method of synthesizing plate-like particles having a uniform particle shape and good dispersibility by making aluminum hydroxide into an aqueous slurry and performing a hydrothermal treatment in an autoclave has been established. The dispersibility at the time of kneading was improved (JP-A-5-17132). However, even with such alumina powder, when plate-like particles are added to an aqueous solvent and used as a slurry for precision polishing or cosmetic use, dispersion in the solvent is difficult to proceed or re-agglomeration after dispersion is likely to occur. There are problems that it is difficult to reduce the surface roughness of the article to be polished, and that it is difficult to sufficiently obtain the spreadability of the cosmetic powder and the glittering property after application.

【０００４】[0004]

【発明が解決しようとする課題】樹脂や各種溶媒に混
合、混練する際、製品として成形体の緻密化、機械的物
性の向上、また塗膜およびスラリーの安定性、塗布後の
乾燥体の光輝性の向上を図るには、樹脂成分や各種溶媒
中の薄片状粒子に高い分散性が必要とされるが、そのた
めには凝集粒子の削減、粒子表面と分散媒体との親和
性、粒子の表面荷電状態が全て良好でないと実現できな
い。When mixed and kneaded with a resin or various solvents, the molded product is densified, the mechanical properties are improved, the stability of the coating film and slurry is maintained, and the brightness of the dried product after application is improved. In order to improve the dispersibility, high dispersibility is required for the flaky particles in the resin component and various solvents. To achieve this, the reduction of agglomerated particles, the affinity between the particle surface and the dispersion medium, the surface of the particles This cannot be achieved unless the charge states are all good.

【０００５】そこで、本発明の目的は水熱合成法で得ら
れるアルミナ粒子の特徴である均一な形状、単一粒子の
分散性を維持しながら、扁平で且つ水系溶媒に対して安
定した分散状態を維持できる配向性の良好な薄片状粒子
を合成することにある。Accordingly, an object of the present invention is to provide a flat and stable dispersion state in an aqueous solvent while maintaining a uniform shape and dispersibility of single particles, which are characteristics of alumina particles obtained by a hydrothermal synthesis method. The present invention is to synthesize flaky particles having good orientation and capable of maintaining the following.

【０００６】[0006]

【課題を解決するための手段】本発明は、（１）平均粒
径０．５〜２５μｍ、平均粒径／粒子厚みで表されるア
スペクト比が５０（５０は含まず）〜２０００の扁平形
状からなることを特徴とする薄片状α−アルミナ粒子、
及び、（２）リン酸化合物がアルミナ粒子に対し、酸化
物換算にてＰ2Ｏ5として０．２〜５．０ｗｔ％存在して
なる前記（１）記載の薄片状α−アルミナ粒子、に係る
ものである。According to the present invention, there is provided (1) a flat shape having an average particle diameter of 0.5 to 25 μm and an aspect ratio expressed by average particle diameter / particle thickness of 50 (not including 50) to 2000. Flaky α-alumina particles, characterized by comprising
And (2) the flaky α-alumina particles according to (1), wherein the phosphate compound is present in the alumina particles in an amount of 0.2 to 5.0 wt% as P 2 O 5 in terms of oxide. It is related.

【０００７】そしてその製造法として、（３）アルミナ
水和物及び／またはアルミナゲルを出発原料として、原
料の平均粒径は２μｍ以下、最大粒径を５μｍ以内と
し、更にアルミナ水和物及び／またはアルミナゲルを１
モルに対し、リン酸イオンを１．０×１０-3〜１．０×
１０ -1モル添加して水系スラリーを水熱合成することを
特徴とする前記（１）又は（２）記載の薄片状α−アル
ミナ粒子の製造方法、並びに、（４）アルミナ水和物及
び／またはアルミナゲルを出発原料として、リン酸イオ
ンの他に種晶として粒径１μｍ未満、比表面積５ｍ2／
ｇ以上のα−アルミナ粒子を原料１モルに対して１．０
×１０-6〜５．０×１０-3モル添加して水熱合成し、薄
片状粒子の粒径を制御することを特徴とする前記（３）
記載の薄片状α−アルミナ粒子の製造方法、に係るもの
である。As a method for producing the same, (3) alumina
Starting from hydrate and / or alumina gel
The average particle size of the material is 2 μm or less, and the maximum particle size is 5 μm or less.
And further add alumina hydrate and / or alumina gel to 1
1.0 × 10-3~ 1.0 ×
10 -1Hydrothermal synthesis of aqueous slurry by adding
The flaky α-al according to the above (1) or (2),
Method for producing mina particles, and (4) alumina hydrate and
And / or alumina gel as starting material
In addition to the seed crystal, the grain size is less than 1 μm and the specific surface area is 5 m.Two/
g or more of α-alumina particles in an amount of 1.0 to 1 mol of the raw material.
× 10-6~ 5.0 × 10-3Hydrothermal synthesis by adding
(3) wherein the particle size of the flaky particles is controlled.
The method for producing flaky α-alumina particles according to the above
It is.

【０００８】本発明において製造される薄片状アルミナ
の形状は図１のようになる。従来の水熱合成法で合成さ
れるα−アルミナ粒子は図２のように（ｎ、ｃ、ａ、
ｒ）等の面にて構成されるが、本発明の薄片状粒子は
（ｎ、ｃ）面でのみ構成される。ここで言う粒子径とは
ｃ面の長軸径、アスペクト比は（ｃ面の長軸径）／（２
つのｃ面間で表される厚みＬ）で表される。算出法は電
子顕微鏡で任意に選んだ１０枚の粒子の平均を取る。The shape of the flaky alumina produced in the present invention is as shown in FIG. As shown in FIG. 2, α-alumina particles synthesized by a conventional hydrothermal synthesis method have (n, c, a,
r), the flaky particles of the present invention are composed only of the (n, c) plane. The particle diameter referred to here is the major axis diameter of the c plane, and the aspect ratio is (major axis diameter of the c plane) / (2
Thickness c) between the two c-planes. The calculation method is to take an average of 10 particles arbitrarily selected by an electron microscope.

【０００９】粒子径は０．５μｍ〜２５μｍ、より好ま
しくは２μｍ〜２０μｍを有するのに対し、厚みＬが薄
いため、アスペクト比は５０（５０は含まず）〜２００
０、好ましくは５０（５０は含まず）〜２００、さらに
好ましくは５５〜２００、さらには６０〜２００とな
る。厚みＬは、前記条件を満たす範囲であるが、特には
０．０１μｍ〜０．２μｍであることが好ましい。Although the particle diameter is 0.5 μm to 25 μm, more preferably 2 μm to 20 μm, the aspect ratio is 50 (excluding 50) to 200 due to the small thickness L.
0, preferably 50 (not including 50) to 200, more preferably 55 to 200, furthermore 60 to 200. The thickness L is in a range that satisfies the above condition, but is particularly preferably 0.01 μm to 0.2 μm.

【００１０】本発明の目的を達成するα−アルミナ粒子
とするには、平均粒径及びアスペクト比が重要であり、
上記の範囲とすることが必要であり、より効果を高める
には、特に粒子の配向性を高めるためには、上記好まし
い範囲とすることが有効である。In order to obtain α-alumina particles for achieving the object of the present invention, the average particle size and the aspect ratio are important.
It is necessary to be within the above-mentioned range, and it is effective to make the above-mentioned preferable range in order to further enhance the effect, particularly to enhance the orientation of the particles.

【００１１】本発明において原料である水酸化アルミニ
ウム、アルミナ水和物は特に限定されるものではなく、
バイヤー法工程より得られたギブサイト型水酸化アルミ
ニウムやアモルファス状のものが使用できる。In the present invention, the raw materials of aluminum hydroxide and alumina hydrate are not particularly limited.
Gibbsite-type aluminum hydroxide obtained from the Bayer process and amorphous materials can be used.

【００１２】これらの原料はあらかじめ粒度調整を行
い、平均粒径は２μｍ以下、最大粒径を５μｍ以内、好
ましくは平均粒径は０．２μｍ〜１．５μｍにするとよ
い。原料の微細化（平均粒径＜０．２μｍ）は合成後の
粒子径が小さくなりすぎ、アスペクト比は相対的に小さ
くなる。さらに粒子径が小さくなると緻密な凝集粒子が
発生し、樹脂や水系スラリーに添加したとき単一粒子へ
分散が進まない。最大粒径５μｍを超える原料を使用し
た場合、合成後に薄片状粒子が強固に凝集した二次粒子
が発生し分散性は向上しない。The particle size of these raw materials is adjusted in advance, and the average particle size is 2 μm or less, the maximum particle size is 5 μm or less, preferably the average particle size is 0.2 μm to 1.5 μm. Finer raw materials (average particle size <0.2 μm) result in too small a particle size after synthesis and a relatively small aspect ratio. When the particle size is further reduced, dense aggregated particles are generated, and when added to a resin or an aqueous slurry, dispersion to single particles does not proceed. When a raw material having a maximum particle size of more than 5 μm is used, secondary particles in which flaky particles are strongly aggregated after the synthesis are generated, and the dispersibility is not improved.

【００１３】原料粉体の粒度調整方法は、ボールミル、
媒体攪拌ミルが主に用いられるが、これに限定されるも
のではない。The method for adjusting the particle size of the raw material powder is a ball mill,
A medium stirring mill is mainly used, but is not limited to this.

【００１４】本発明は、上記原料と水を混合したスラリ
ーを水熱合成する。このスラリーの濃度は、１ｗｔ％〜
６０ｗｔ％、好ましくは２０ｗｔ％〜５０ｗｔ％であ
る。６０ｗｔ％を超えると凝集粒子が発生する傾向を示
すためである。In the present invention, a slurry obtained by mixing the above-mentioned raw materials and water is hydrothermally synthesized. The concentration of this slurry is 1wt% ~
It is 60 wt%, preferably 20 wt% to 50 wt%. If the content exceeds 60% by weight, a tendency to generate aggregated particles is exhibited.

【００１５】薄片状粒子の厚さを薄くし、アスペクト比
を大きくするには、リン酸イオンを原料１モルに対し
１．０×１０-3〜１．０×１０-1モルの範囲内で、リン
酸添加量を増やすことが有効である。リン酸イオンを添
加する場合、オルトリン酸、メタリン酸、ピロリン酸の
水溶液を添加するが必ずしもこれに限られるものではな
い。ホスホン酸、ホスフィン酸や、リン酸二水素ナトリ
ウム、リン酸一水素アンモニウム等のリン酸塩であって
も構わない。原料１モルに対しリン酸イオン添加量が
１．０×１０-3モル未満では合成後の粒子は厚みがあり
アスペクト比が５０を超える薄片状粒子が合成できにく
くなる。原料１モルに対しリン酸イオン添加量が１．０
×１０-1モルを超えると合成後に薄片状粒子が凝集した
二次粒子が多くなってしまう。In order to reduce the thickness of the flaky particles and increase the aspect ratio, phosphate ions are added within a range of 1.0 × 10 -3 to 1.0 × 10 -1 mol per mol of the raw material. It is effective to increase the amount of phosphoric acid added. When adding phosphate ions, an aqueous solution of orthophosphoric acid, metaphosphoric acid, or pyrophosphoric acid is added, but is not necessarily limited thereto. Phosphonic acid, phosphinic acid, and phosphates such as sodium dihydrogen phosphate and ammonium monohydrogen phosphate may be used. If the amount of added phosphate ions is less than 1.0 × 10 −3 mol per mol of the raw material, the synthesized particles have a large thickness, and it is difficult to synthesize flaky particles having an aspect ratio exceeding 50. Phosphate ion addition amount is 1.0 per mole of raw material
If it exceeds × 10 −1 mol, the number of secondary particles in which the flaky particles are aggregated after the synthesis increases.

【００１６】薄片状粒子の平均粒径を制御するには原料
と水を混合したスラリーに種晶として粒径１μｍ未満、
比表面積５ｍ2／ｇ以上のα−アルミナ粒子を添加する
方法が有効である。種晶は超音波等で分散させてスラリ
ーの中に添加するのが望ましい。この条件で種晶を添加
すると、添加量の増量に伴って合成後の薄片状アルミナ
粒子を微細化することができる。粒径１μｍ以上の種晶
を添加すると、合成後に厚みが０．２μｍ以上ある粒子
が増え、薄片状粒子はできにくくなる。比表面積が５ｍ
2／ｇ未満の種晶では粒径の制御は難しい。添加量は原
料１モルに対して１．０×１０-6〜５．０×１０-3モル
が好ましい。５．０×１０-3モルより多く添加しても、
粒径を微細化させる効果は小さくなってしまう。上記の
種晶添加により、薄片状アルミナの平均粒径を０．５〜
２５μｍの間で制御することができる。In order to control the average particle size of the flaky particles, a slurry in which a raw material and water are mixed is used as a seed crystal to have a particle size of less than 1 μm,
It is effective to add α-alumina particles having a specific surface area of 5 m 2 / g or more. The seed crystal is desirably dispersed in an ultrasonic wave or the like and added to the slurry. When the seed crystal is added under these conditions, the flaky alumina particles after synthesis can be made finer as the amount of addition increases. When a seed crystal having a particle diameter of 1 μm or more is added, particles having a thickness of 0.2 μm or more after synthesis increase, and it becomes difficult to form flaky particles. Specific surface area is 5m
With a seed crystal of less than 2 / g, it is difficult to control the particle size. The addition amount is preferably from 1.0 × 10 −6 to 5.0 × 10 −3 mol per 1 mol of the raw material. Even if more than 5.0 × 10 -3 mol is added,
The effect of reducing the particle size is reduced. By the above seed crystal addition, the average particle size of the flaky alumina is 0.5 to
It can be controlled between 25 μm.

【００１７】水熱合成の反応温度は４００℃以上であ
り、好ましくは４５０℃以上である。スラリーの最高温
度が４００〜４５０℃になる場合、α−アルミナ化の反
応を完了させるために昇温後、温度保持時間を２４時間
以上要する。合成圧力は１０ＭＰａ〜２５ＭＰａ、好ま
しくは１５ＭＰａ〜２０ＭＰａとする。合成温度・圧力
の関係はＡｌ2Ｏ3−Ｈ2Ｏ系状態図でα−Ａｌ2Ｏ3（コ
ランダム）の範囲でなければならない。合成圧力１０Ｍ
Ｐａ以上を要するのは、この範囲を外れた低圧下では、
薄片状粒子の他に粒状形をした粒子の混在状態で合成さ
れ、粒子径のばらつきが大きくなる。また合成圧力２０
ＭＰａ以上になると粒子は厚肉化の傾向を示し、２５Ｍ
Ｐａを超えると厚肉化しすぎるので好ましくない。The reaction temperature of the hydrothermal synthesis is 400 ° C. or higher, preferably 450 ° C. or higher. When the maximum temperature of the slurry reaches 400 to 450 ° C., a temperature holding time of 24 hours or more is required after the temperature is raised to complete the α-aluminaization reaction. The synthesis pressure is 10 MPa to 25 MPa, preferably 15 MPa to 20 MPa. The relationship between the synthesis temperature and the pressure must be within the range of α-Al 2 O 3 (corundum) in the Al 2 O 3 —H 2 O phase diagram. Synthetic pressure 10M
The reason for requiring Pa or more is that under low pressure outside this range,
The particles are synthesized in a mixed state of granular particles in addition to the flaky particles, and the dispersion of the particle diameter becomes large. In addition, the synthesis pressure 20
When the pressure exceeds MPa, the particles show a tendency to thicken,
If it exceeds Pa, it is not preferable because it becomes too thick.

【００１８】[0018]

【作用】本発明により、平均粒径０．５μｍ〜２５μ
ｍ、アスペクト比５０（５０は含まず）〜２０００であ
る薄片状α−アルミナ粒子を合成することができる。そ
の際、種晶の添加量を規定することによって平均粒子径
が上記範囲にて制御できる。According to the present invention, the average particle size is 0.5 μm to 25 μm.
m, and flaky α-alumina particles having an aspect ratio of 50 (not including 50) to 2000 can be synthesized. At this time, the average particle diameter can be controlled in the above range by defining the amount of the seed crystal to be added.

【００１９】この粒子は凝集粒子が少なく、フィラーと
してプラスチック及びゴムの中に混練したとき、薄片状
粒子は良分散状態となる。さらに粒子の扁平性が高いの
で、この樹脂とフィラーの複合体をシート状に成形した
時の成形体の引張強度、スティフネス等の機械的強度が
向上する。また、成形後の温度低下に伴う収縮率も低下
する。These particles have a small amount of agglomerated particles, and when kneaded in a plastic or rubber as a filler, the flaky particles are in a good dispersion state. Further, since the flatness of the particles is high, the mechanical strength such as the tensile strength and the stiffness of the molded body when the composite of the resin and the filler is molded into a sheet is improved. In addition, the shrinkage rate accompanying the temperature decrease after molding also decreases.

【００２０】また、塗料用顔料や塗工剤として使用した
場合、塗装後薄片状粒子は塗膜中に平行に配向すること
により、塗膜の劣化を防ぎ、また塗膜内部への腐食物質
の侵入防止効果が期待できる。塗膜表面への粒子の突出
は確認されないことから、優れた表面平滑性を持ち、光
沢性を示す塗膜とすることができる。In addition, when used as a paint pigment or a coating agent, the flaky particles after coating are oriented in parallel in the coating film to prevent deterioration of the coating film and to prevent corrosive substances from entering the inside of the coating film. Intrusion prevention effect can be expected. Since no protrusion of particles to the surface of the coating film is confirmed, a coating film having excellent surface smoothness and exhibiting gloss can be obtained.

【００２１】さらに、この粒子の特徴として、水系溶媒
との親和性も良好であり、攪拌等の簡単な分散操作で安
定的な単一粒子の分散状態を維持することが可能にな
る。ゆえに、精密研磨用スラリーや化粧用途として水系
溶媒に分散させて使用した場合、非研磨物の表面平滑性
の向上や液体化粧品の安定性、進展性向上が期待でき
る。水系溶媒中で本粒子の分散性が良好な理由は定かで
はないが、最も重要な要因としては、α−アルミナ粒子
の薄片状形態にあり、上記平均粒子径であり、アスペク
ト比を有することが重要である。粒子の表面にリン酸イ
オンが存在し、粒子表面が若干帯電して粒子間に斥力が
働くことが重要な要因の一つと推定される。Further, as a characteristic of these particles, they have a good affinity for an aqueous solvent and can maintain a stable single particle dispersion state by a simple dispersion operation such as stirring. Therefore, when it is used after being dispersed in an aqueous solvent as a slurry for precision polishing or as a cosmetic application, it can be expected to improve the surface smoothness of a non-abrasive and to improve the stability and progress of a liquid cosmetic. The reason why the dispersibility of the particles is good in the aqueous solvent is not clear, but the most important factor is that the α-alumina particles are in the form of flakes, the average particle diameter is the above, and the aspect ratio is is important. It is presumed that one of the important factors is that phosphate ions are present on the surface of the particles, the surface of the particles is slightly charged, and repulsion acts between the particles.

【００２２】[0022]

【発明の実施の形態】以下、具体的な実施例について述
べる。 実施例１ バイヤー法にて得られたギブサイト型水酸化アルミニウ
ムを平均粒径１．１μｍに調整し、原料１モルに対しオ
ルトリン酸３．０×１０-3モル添加し、５０ｗｔ％濃度
の水系スラリーにしてから、合成温度６００℃、合成圧
力１５ＭＰａにて水熱合成を行い、水洗、乾燥後白色の
粉体を得た。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments will be described. Example 1 Gibbsite type aluminum hydroxide obtained by the Bayer method was adjusted to an average particle diameter of 1.1 μm, and 3.0 × 10 −3 mol of orthophosphoric acid was added to 1 mol of the raw material, and a 50 wt% aqueous slurry was added. After that, hydrothermal synthesis was performed at a synthesis temperature of 600 ° C. and a synthesis pressure of 15 MPa, washed with water and dried to obtain a white powder.

【００２３】粉体は平均粒径１２．０μｍ、平均厚み
０．１５μｍ、アスペクト比は８０の薄片状粒子であっ
た。蛍光Ｘ線による粉体中の組成分析の結果、酸化物換
算でＰ 2Ｏ5０．３ｗｔ％を含有していることが確認され
た。The powder has an average particle size of 12.0 μm and an average thickness.
0.15 μm, flaky particles with an aspect ratio of 80
Was. As a result of composition analysis in powder by X-ray fluorescence,
By calculation TwoOFiveIt was confirmed to contain 0.3 wt%
Was.

【００２４】さらに粒子は、１）樹脂への添加、２）水
性溶媒への添加実験を行い分散性をそれぞれ評価した。The particles were further subjected to 1) addition to a resin and 2) addition to an aqueous solvent to evaluate their dispersibility.

【００２５】１）それぞれの粒子１００部に対し、アク
リルラッカー（水谷ペイント製）５０部、トルエン２０
部、メチルエチルケトン１０部を添加し、ホモジナイザ
ーにて（ｉｋａ製 ＬＲ−４１Ｂ、１０００ｒｐｍ）５
分間攪拌を行い、ガラス板上にこのスラリーを塗布後、
５０℃で１時間加熱乾燥し硬化した。1) For 100 parts of each particle, 50 parts of acrylic lacquer (manufactured by Mizutani Paint) and 20 parts of toluene
And 10 parts of methyl ethyl ketone, and the mixture was treated with a homogenizer (LR-41B, manufactured by ika, 1000 rpm).
Stir for a minute, apply this slurry on a glass plate,
It was dried by heating at 50 ° C. for 1 hour.

【００２６】２）それぞれの粒子１００部に対し、純水
を４０部添加し、ホモジナイザーにて（ｉｋａ製 ＬＲ
−４１Ｂ、１０００ｒｐｍ）５分間攪拌を行い、ガラス
板上にこのスラリーを塗布後、１２０℃で３０秒間乾燥
させた。2) 40 parts of pure water was added to 100 parts of each particle, and a homogenizer (LR manufactured by ika) was used.
The slurry was applied on a glass plate, and dried at 120 ° C. for 30 seconds.

【００２７】各々のガラス板上にある成形体をＸ線回折
分析し、Ｌｏｔｇｅｒｉｎｇ法により、粉体の配向度を
算出した。分散性が高い程配向度の数値は大きくなり、
１に近い値を取る。１）樹脂添加実験の配向度は０．９
１、２）水性溶媒添加実験の配向度は０．８４となっ
た。The compact on each glass plate was subjected to X-ray diffraction analysis, and the degree of powder orientation was calculated by Lotgering method. The higher the degree of dispersion, the larger the value of the degree of orientation,
Take a value close to one. 1) The degree of orientation in the resin addition experiment was 0.9.
1, 2) The degree of orientation in the aqueous solvent addition experiment was 0.84.

【００２８】実施例２ 上記実施例１において、原料１モルに対し、オルトリン
酸の添加量を１．０×１０-2モルに増量し、水熱合成を
行い白色の粉体を得た。Example 2 In Example 1, the amount of orthophosphoric acid was increased to 1.0 × 10 -2 mol per mol of the raw material, and hydrothermal synthesis was performed to obtain a white powder.

【００２９】粉体は、平均粒径１１．０μｍ、平均厚み
０．０７μｍ、アスペクト比は約１６０の薄片状粒子で
あった。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ5
０．９ｗｔ％を含有していることが確認された。１）樹
脂添加実験の配向度は０．９０、２）水性溶媒添加実験
の配向度は０．８８となった。The powder was flaky particles having an average particle size of 11.0 μm, an average thickness of 0.07 μm, and an aspect ratio of about 160. As a result of analyzing the composition in the powder, it was found that P 2 O 5
It was confirmed that it contained 0.9 wt%. 1) The degree of orientation in the experiment for adding the resin was 0.90, and 2) the degree of orientation in the experiment for adding the aqueous solvent was 0.88.

【００３０】実施例３ 上記実施例２において、オルトリン酸の他、種晶として
粒径０．１μｍのα−アルミナ粒子（大明化学工業製：
ＴＭ−ＤＡＲ ＢＥＴ 比表面積１４ｍ2／ｇ）を原料
１モルに対し８．０×１０-6モル添加し、水系スラリー
にして水熱合成を行い白色の粉体を得た。Example 3 In Example 2, in addition to orthophosphoric acid, α-alumina particles having a particle size of 0.1 μm as seed crystals (manufactured by Daimei Chemical Co., Ltd .:
(TM-DAR BET specific surface area: 14 m 2 / g) was added in an amount of 8.0 × 10 −6 mol per 1 mol of the raw material, and the resulting slurry was subjected to hydrothermal synthesis to obtain a white powder.

【００３１】粉体は、平均粒径７．５μｍ、平均厚み
０．０５μｍ、アスペクト比は１５０の薄片状粒子であ
った。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ
5０．８ｗｔ％を含有していることが確認された。１）
樹脂添加実験の配向度は０．８８、２）水性溶媒添加実
験の配向度は０．８２となった。The powder was flaky particles having an average particle size of 7.5 μm, an average thickness of 0.05 μm, and an aspect ratio of 150. As a result of composition analysis in the powder, P 2 O
It was confirmed to contain 5 0.8 wt%. 1)
The orientation in the resin addition experiment was 0.88, and the orientation in the aqueous solvent addition experiment was 0.82.

【００３２】実施例４ 上記実施例２において、オルトリン酸の他、種晶として
粒径０．１μｍのα−アルミナ粒子（大明化学工業製：
ＴＭ−ＤＡＲ ＢＥＴ 比表面積１４ｍ2／ｇ）を原料
１モルに対し８．０×１０-5モル添加し、水系スラリー
にして水熱合成を行い白色の粉体を得た。Example 4 In Example 2, in addition to orthophosphoric acid, α-alumina particles having a particle size of 0.1 μm as seed crystals (manufactured by Daimei Chemical Co., Ltd .:
(TM-DAR BET specific surface area: 14 m 2 / g) was added in an amount of 8.0 × 10 −5 mol per mol of the raw material, and the resulting slurry was subjected to hydrothermal synthesis to obtain a white powder.

【００３３】粉体は、平均粒径４．８μｍ、平均厚み
０．０４μｍ、アスペクト比は１２０の薄片状粒子であ
った。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ
5０．８ｗｔ％を含有していることが確認された。１）
樹脂添加実験の配向度は０．８９、２）水性溶媒添加実
験の配向度は０．８１となった。The powder was flaky particles having an average particle size of 4.8 μm, an average thickness of 0.04 μm, and an aspect ratio of 120. As a result of composition analysis in the powder, P 2 O
It was confirmed to contain 5 0.8 wt%. 1)
The degree of orientation in the resin addition experiment was 0.89, and the degree of orientation in the aqueous solvent addition experiment was 0.81.

【００３４】比較例１ 上記実施例１において、原料の平均粒径を４．０μｍに
調整して、オルトリン酸を添加せずに水系スラリーにし
て水熱合成を行い、水洗、乾燥後白色の粉体を得た。Comparative Example 1 In Example 1, the average particle size of the raw materials was adjusted to 4.0 μm, and a hydrothermal synthesis was performed using an aqueous slurry without adding orthophosphoric acid. I got a body.

【００３５】粉体は、平均粒径５．０μｍ、平均厚み
０．７５μｍ、アスペクト比は約７の板状粒子であっ
た。粉体中の組成分析の結果、酸化物換算でＰ2Ｏ5は含
有されていないことが確認された。１）樹脂添加実験の
配向度は０．４２、２）水性溶媒添加実験の配向度は
０．３９となった。The powder was plate-like particles having an average particle size of 5.0 μm, an average thickness of 0.75 μm, and an aspect ratio of about 7. As a result of composition analysis in the powder, it was confirmed that P 2 O 5 was not contained in terms of oxide. 1) The degree of orientation in the resin addition experiment was 0.42, and the degree of orientation in the aqueous solvent addition experiment was 0.39.

【００３６】比較例２ 上記実施例２において、種晶として粒径２．０μｍ、比
表面積１５ｍ2／ｇのα−アルミナ粒子を原料１モルに
対し８．０×１０-5モル添加し、水系スラリーにして水
熱合成を行い白色の粉体を得た。Comparative Example 2 In Example 2, 8.0 × 10 -5 mol of α-alumina particles having a particle size of 2.0 μm and a specific surface area of 15 m 2 / g were added as a seed crystal to 1 mol of the raw material, The slurry was subjected to hydrothermal synthesis to obtain a white powder.

【００３７】粉体は、平均粒径１０．５μｍ、平均厚み
０．３０μｍ、アスペクト比は３５の粒子であった。粉
体中の組成分析の結果、酸化物換算でＰ2Ｏ5０．８ｗｔ
％を含有していることが確認された。１）樹脂添加実験
の配向度は０．６０、２）水性溶媒添加実験の配向度は
０．４３となった。各種粉体の製造条件を表１、粉体の
粒子形状、組成、分散性を示す配向度を表２に示す。The powder had an average particle size of 10.5 μm, an average thickness of 0.30 μm, and an aspect ratio of 35. As a result of the composition analysis of the powder, P 2 O 5 0.8wt in terms of oxide
% Was confirmed to be contained. 1) The degree of orientation in the experiment for adding the resin was 0.60, and 2) the degree of orientation in the experiment for adding the aqueous solvent was 0.43. Table 1 shows the production conditions of various powders, and Table 2 shows the degree of orientation indicating the particle shape, composition, and dispersibility of the powder.

【００３８】[0038]

【表１】 [Table 1]

【００３９】[0039]

【表２】 [Table 2]

【００４０】[0040]

【発明の効果】以上のように本発明の薄片状α−アルミ
ナ粒子の効果として、平均粒径０．５〜２５μｍ、アス
ペクト比５０（５０は含まず）〜２０００である薄片状
α−アルミナ粒子であり、単一粒子の分散性を維持しな
がら、扁平で且つ水系溶媒に対して安定した分散状態を
維持することができるため、粒子の配向性を向上させる
ことができる。As described above, as the effects of the flaky α-alumina particles of the present invention, the flaky α-alumina particles having an average particle size of 0.5 to 25 μm and an aspect ratio of 50 (not including 50) to 2,000. In addition, since a flat and stable dispersion state in an aqueous solvent can be maintained while maintaining the dispersibility of the single particles, the orientation of the particles can be improved.

【００４１】特に、粒子中に含まれるリン酸イオンの効
果により、樹脂中に混練する時だけでなく、水系溶媒に
添加させた際にもより容易に単一粒子に分散し高分散性
の特徴を発揮するアルミナ粒子を提供することができ
る。この粉体をフィラーとして混練したプラスチックや
ゴム等は、その優れた分散性により補強効果が得られ
る。また、塗料用顔料や塗工剤として各種溶媒に分散さ
せて使用した場合、塗料の粘度上昇が抑えられることに
より、流動性、塗工性が維持できる。塗装後、薄片状粒
子は塗膜中に平行に配向することにより、塗膜の劣化を
防ぎ、また塗膜内部への物質の侵入防止効果が期待でき
る。また表面の平滑性が高く、光沢性のある塗膜を得る
ことができる。さらに当粉体を使用した研磨用スラリー
は、被研磨物の表面平滑性を向上させることができ、化
粧品として当粉体を使用すると進展性の向上効果も発揮
することができる。また、本発明の薄片状α−アルミナ
粒子の製造方法によれば、上記優れた特性を有する薄片
状α−アルミナ粒子を容易に、さらに効率よく製造する
ことができる。In particular, due to the effect of phosphate ions contained in the particles, not only when kneading into the resin, but also when added to an aqueous solvent, the particles are more easily dispersed into single particles and have a characteristic of high dispersibility. Can be provided. Plastics, rubbers, and the like obtained by kneading this powder as a filler have a reinforcing effect due to their excellent dispersibility. In addition, when used as a paint pigment or a coating agent after being dispersed in various solvents, the increase in viscosity of the paint is suppressed, so that fluidity and coatability can be maintained. After coating, the flaky particles are oriented in parallel in the coating film, thereby preventing the coating film from deteriorating and preventing the substance from entering the inside of the coating film. Further, a glossy coating film having high surface smoothness can be obtained. Further, the polishing slurry using the powder can improve the surface smoothness of the object to be polished, and the use of the powder as a cosmetic can also exhibit the effect of improving the spreadability. Further, according to the method for producing flaky α-alumina particles of the present invention, flaky α-alumina particles having the above-mentioned excellent properties can be produced easily and more efficiently.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明により製造される薄片状粒子の形状を表
す模式図である。FIG. 1 is a schematic view showing the shape of a flaky particle produced according to the present invention.

【図２】従来の水熱合成法により作製される板状粒子の
形状を表す模式図である。FIG. 2 is a schematic diagram showing the shape of plate-like particles produced by a conventional hydrothermal synthesis method.

───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4G076 AA02 AB02 AB06 AC04 BA12 BA24 BA26 BA43 BB04 BC07 BD02 BD04 CA02 CA08 CA26 CA29 CA36 DA02 DA15 FA02 4J037 AA25 CA09 CA21 DD05 DD12 DD27 EE16 EE43 FF15 FF18 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G076 AA02 AB02 AB06 AC04 BA12 BA24 BA26 BA43 BB04 BC07 BD02 BD04 CA02 CA08 CA26 CA29 CA36 DA02 DA15 FA02 4J037 AA25 CA09 CA21 DD05 DD12 DD27 EE16 EE43 FF15 FF18

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】 平均粒径０．５〜２５μｍ、平均粒径／
粒子厚みで表されるアスペクト比が５０（５０は含ま
ず）〜２０００の扁平形状からなることを特徴とする薄
片状α−アルミナ粒子。An average particle size of 0.5 to 25 μm,
Flaky α-alumina particles having a flat shape having an aspect ratio represented by a particle thickness of 50 (not including 50) to 2,000. 【請求項２】 リン酸化合物がアルミナ粒子に対し、酸
化物換算にてＰ2Ｏ5として０．２〜５．０ｗｔ％存在し
てなる請求項１記載の薄片状α−アルミナ粒子。2. The flaky α-alumina particles according to claim 1, wherein the phosphoric acid compound is present in an amount of 0.2 to 5.0 wt% as P 2 O 5 in terms of oxide based on the alumina particles. 【請求項３】 前記粒子のゼータ電位が０を示す等電位
点が、ｐＨ２〜５を示す請求項１又は２記載の薄片状α
−アルミナ粒子。3. The flaky α according to claim 1, wherein the zeta potential of the particles at which the zeta potential is 0 is pH 2 to 5.
-Alumina particles. 【請求項４】 アルミナ水和物及びアルミナゲルを出発
原料として、原料の平均粒径は２μｍ以下、最大粒径を
５μｍ以内とし、更にアルミナ水和物またはアルミナゲ
ルを１モルに対し、リン酸イオンを１．０×１０-3〜
１．０×１０-1モル添加して水系スラリーを水熱合成す
ることを特徴とする請求項１、２又は３記載の薄片状α
−アルミナ粒子の製造方法。4. Starting from alumina hydrate and alumina gel, the raw material has an average particle size of 2 μm or less and a maximum particle size of 5 μm or less. 1.0 × 10 -3 ions
4. The flaky α according to claim 1, wherein the aqueous slurry is hydrothermally synthesized by adding 1.0 × 10 −1 mol.
-A method for producing alumina particles. 【請求項５】 アルミナ水和物及びアルミナゲルを出発
原料として、リン酸イオンの他に種晶として粒径１μｍ
未満、比表面積５ｍ2／ｇ以上のα−アルミナ粒子を原
料１モルに対して１．０×１０-6〜５．０×１０-3モル
添加して水熱合成し、薄片状粒子の粒径を制御すること
を特徴とする請求項４記載の薄片状α−アルミナ粒子の
製造方法。5. Using alumina hydrate and alumina gel as starting materials, a particle having a particle size of 1 μm as a seed crystal in addition to phosphate ions.
Α-alumina particles having a specific surface area of 5 m 2 / g or more are added in an amount of 1.0 × 10 −6 to 5.0 × 10 −3 mol per 1 mol of the raw material, and hydrothermal synthesis is performed. The method for producing flaky α-alumina particles according to claim 4, wherein the diameter is controlled.
JP2001040237A 2000-04-17 2001-02-16 THIN-CHIP FOAM alpha-ALUMINA PARTICLE AND METHOD FOR PRODUCING THE SAME Pending JP2002249315A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2001040237A JP2002249315A (en) 2001-02-16 2001-02-16 THIN-CHIP FOAM alpha-ALUMINA PARTICLE AND METHOD FOR PRODUCING THE SAME
EP01109347A EP1148028A3 (en) 2000-04-17 2001-04-12 Flake-like alpha-alumina particles and method for producing the same
US09/834,651 US7067157B2 (en) 2000-04-17 2001-04-16 Flaky α-alumina particles and method for producing the same
KR10-2001-0044963A KR100451589B1 (en) 2001-02-16 2001-07-25 FLAKE-LIKE α-ALUMINA PARTICLES AND METHOD FOR PRODUCING THE SAME

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2001040237A JP2002249315A (en) 2001-02-16 2001-02-16 THIN-CHIP FOAM alpha-ALUMINA PARTICLE AND METHOD FOR PRODUCING THE SAME

Publications (1)

Publication Number Publication Date
JP2002249315A true JP2002249315A (en) 2002-09-06

Family

ID=18902883

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2001040237A Pending JP2002249315A (en) 2000-04-17 2001-02-16 THIN-CHIP FOAM alpha-ALUMINA PARTICLE AND METHOD FOR PRODUCING THE SAME

Country Status (2)

Country Link
JP (1) JP2002249315A (en)
KR (1) KR100451589B1 (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006065917A (en) * 2004-08-25 2006-03-09 Sumitomo Chemical Co Ltd alpha-ALUMINA POWDER FOR MAGNETIC RECORDING MEDIUM
JP2006331703A (en) * 2005-05-24 2006-12-07 Kinsei Matec Co Ltd Conductive powder and its manufacturing method
JP2007031259A (en) * 2005-06-22 2007-02-08 Nissan Motor Co Ltd Metal oxide particle composite, metal oxide composite sol, and method for producing metal oxide composite sol
JP2014503626A (en) * 2010-12-09 2014-02-13 メルク パテント ゲゼルシャフト ミット ベシュレンクテル ハフツング Brilliant black pigment
WO2020021675A1 (en) 2018-07-26 2020-01-30 Dic株式会社 Tabular alumina particle and method for manufacturing tabular alumina particle
WO2020036139A1 (en) 2018-08-15 2020-02-20 Dic株式会社 Tabular alumina particles and method of producing tabular alumina particles
KR20210106419A (en) 2018-12-28 2021-08-30 디아이씨 가부시끼가이샤 Plate-shaped alumina particles, manufacturing method of plate-shaped alumina particles, and resin composition
KR20220079556A (en) 2019-10-09 2022-06-13 디아이씨 가부시끼가이샤 Plate-shaped alumina particles and manufacturing method of plate-shaped alumina particles
KR20220080123A (en) 2019-10-09 2022-06-14 디아이씨 가부시끼가이샤 Composite Particles and Methods of Making Composite Particles
KR20230130007A (en) 2021-01-13 2023-09-11 디아이씨 가부시끼가이샤 Composite particles and methods for producing composite particles

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100824438B1 (en) 2006-08-14 2008-04-23 씨큐브 주식회사 Flake, low gloss pigment for cosmetic

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006065917A (en) * 2004-08-25 2006-03-09 Sumitomo Chemical Co Ltd alpha-ALUMINA POWDER FOR MAGNETIC RECORDING MEDIUM
JP4670279B2 (en) * 2004-08-25 2011-04-13 住友化学株式会社 Alpha alumina powder for magnetic recording media
JP2006331703A (en) * 2005-05-24 2006-12-07 Kinsei Matec Co Ltd Conductive powder and its manufacturing method
JP2007031259A (en) * 2005-06-22 2007-02-08 Nissan Motor Co Ltd Metal oxide particle composite, metal oxide composite sol, and method for producing metal oxide composite sol
JP2014503626A (en) * 2010-12-09 2014-02-13 メルク パテント ゲゼルシャフト ミット ベシュレンクテル ハフツング Brilliant black pigment
WO2020021675A1 (en) 2018-07-26 2020-01-30 Dic株式会社 Tabular alumina particle and method for manufacturing tabular alumina particle
US11926531B2 (en) 2018-07-26 2024-03-12 Dic Corporation Flaky alumina particles and method for producing flaky alumina particles
KR20210037603A (en) 2018-07-26 2021-04-06 디아이씨 가부시끼가이샤 Plate-shaped alumina particles, and method for producing plate-shaped alumina particles
KR20210040938A (en) 2018-08-15 2021-04-14 디아이씨 가부시끼가이샤 Plate-shaped alumina particles, and method for producing plate-shaped alumina particles
US11905420B2 (en) 2018-08-15 2024-02-20 Dic Corporation Tabular alumina particles and method of producing tabular alumina particles
WO2020036139A1 (en) 2018-08-15 2020-02-20 Dic株式会社 Tabular alumina particles and method of producing tabular alumina particles
KR20210106419A (en) 2018-12-28 2021-08-30 디아이씨 가부시끼가이샤 Plate-shaped alumina particles, manufacturing method of plate-shaped alumina particles, and resin composition
DE112019006406T5 (en) 2018-12-28 2021-09-30 Dic Corporation LABEL-LIKE ALUMINUM PARTICLES, METHOD FOR MANUFACTURING LABEL-LIKE ALUMINUM PARTICLES, AND RESIN COMPOSITION
KR20220079556A (en) 2019-10-09 2022-06-13 디아이씨 가부시끼가이샤 Plate-shaped alumina particles and manufacturing method of plate-shaped alumina particles
KR20220080123A (en) 2019-10-09 2022-06-14 디아이씨 가부시끼가이샤 Composite Particles and Methods of Making Composite Particles
KR20230130007A (en) 2021-01-13 2023-09-11 디아이씨 가부시끼가이샤 Composite particles and methods for producing composite particles

Also Published As

Publication number Publication date
KR100451589B1 (en) 2004-10-08
KR20020067404A (en) 2002-08-22

Similar Documents

Publication Publication Date Title
US6015456A (en) Alumina particles having high dispersibility and plasticity
JP3694627B2 (en) Method for producing flaky boehmite particles
JP5204663B2 (en) Highly filled transition aluminum oxide-containing dispersion
JP6660078B2 (en) Method for producing titanium phosphate powder, white pigment for cosmetics
JP4122746B2 (en) Method for producing fine α-alumina powder
KR0156253B1 (en) Platelet-like substrates
JP2002249315A (en) THIN-CHIP FOAM alpha-ALUMINA PARTICLE AND METHOD FOR PRODUCING THE SAME
WO2020158332A1 (en) Titanium phosphate powder and white pigment for cosmetic preparations
JP3906072B2 (en) Plate-like alumina particles, cosmetics using the same, and method for producing the same
JP3759208B2 (en) Method for producing alumina particles
JP2003192452A (en) Zirconia powder and sintered compact thereof
JPS61201623A (en) Production of spherical flocculated particle of zirconia ultrafine crystal
US7067157B2 (en) Flaky α-alumina particles and method for producing the same
WO2003076524A1 (en) Process for production of titanium dioxide pigment and resin compositions containing the pigment
WO2019159923A1 (en) Flaky titanic acid and method for production thereof, and use thereof
JP3799558B2 (en) Barium sulfate, process for producing the same and resin composition
EP4023207A1 (en) Modified boron nitride powder
US20030234304A1 (en) Superfine powders and methods for manufacture of said powders
US6786964B2 (en) Fine particle of aluminum hydroxide for filling resin and resin composition using the same
JP3398640B2 (en) Manufacturing method of oriented flake zinc oxide
JPS59122554A (en) Preparation of surface-treating barium sulfate
JPH07315832A (en) Silica-modified alumina sol and its production
EP4303180A1 (en) Hexagonal boron nitride agglomerated particles, hexagonal boron nitride powder, resin composition, and resin sheet
JP3708985B2 (en) Alkaline alumina sol and method for producing the same
CN115011142B (en) Method for preparing aluminum oxide-based pearlescent pigment through hydrothermal method

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20031208

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A711

Effective date: 20040220

RD03 Notification of appointment of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7423

Effective date: 20040220

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20060922

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20061129

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20070320