JPH0470257B2 - - Google Patents
Info
- Publication number
- JPH0470257B2 JPH0470257B2 JP1119092A JP11909289A JPH0470257B2 JP H0470257 B2 JPH0470257 B2 JP H0470257B2 JP 1119092 A JP1119092 A JP 1119092A JP 11909289 A JP11909289 A JP 11909289A JP H0470257 B2 JPH0470257 B2 JP H0470257B2
- Authority
- JP
- Japan
- Prior art keywords
- silica
- flame
- porous
- particle size
- fine particles
- 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
Links
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 103
- 239000000377 silicon dioxide Substances 0.000 claims description 45
- 239000002245 particle Substances 0.000 claims description 35
- 239000010419 fine particle Substances 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 230000003301 hydrolyzing effect Effects 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 11
- 239000011148 porous material Substances 0.000 description 11
- 230000007062 hydrolysis Effects 0.000 description 10
- 238000006460 hydrolysis reaction Methods 0.000 description 10
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 239000002002 slurry Substances 0.000 description 8
- 239000000843 powder Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 229910001868 water Inorganic materials 0.000 description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 238000000635 electron micrograph Methods 0.000 description 6
- 239000003960 organic solvent Substances 0.000 description 6
- 238000005507 spraying Methods 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 5
- 239000000945 filler Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 4
- 229910001882 dioxygen Inorganic materials 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 3
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000000344 soap Substances 0.000 description 1
- UQMOLLPKNHFRAC-UHFFFAOYSA-N tetrabutyl silicate Chemical compound CCCCO[Si](OCCCC)(OCCCC)OCCCC UQMOLLPKNHFRAC-UHFFFAOYSA-N 0.000 description 1
- ZQZCOBSUOFHDEE-UHFFFAOYSA-N tetrapropyl silicate Chemical compound CCCO[Si](OCCC)(OCCC)OCCC ZQZCOBSUOFHDEE-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
- C01B33/181—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by a dry process
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/30—Particle morphology extending in three dimensions
- C01P2004/32—Spheres
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/50—Agglomerated particles
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
Description
［産業上の利用分野］
本発明は球状シリカ微粒子、特にはアルコキシ
シランの加水分解で得られたシリカを火炎で乾
燥、無孔化してなる、粒度分布が狭く無孔質なこ
とからプラスチツクパツケージ用充填剤として有
用とされる球状シリカ微粒子およびその製造方法
に関するものである。
［従来の技術］
シリカの製造方法については各種の方法が知ら
れており、アルコキシシランを加水分解して得ら
れるシリカは粒度分布が狭く、高純度のものにな
るが、これにはアルカリ触媒としてアンモニアを
用いたNH3−H2Ｏ−アルコール溶液中にアルコ
キシシラン−アルコール溶液を滴下して粒径が
0.02〜1μｍのシリカを得る方法［J.Colloid
Interface Sci.26，62（1968）参照］、塩酸などの
酸性触媒の存在下に水および／またはアルコール
溶液をアルコキシシランに添加して粒径１〜
500μｍのシリカを得る方法（特開昭62−138335
号公報参照）が提案されている。
しかし、これらの方法で得られるシリカは微細
な細孔を有するためにBET法による比表面積が
10〜300m2／ｇと非常に大きいので、これを例え
ばICなどのプラスチツクパツケージ用充填剤と
して使用すると、その細孔内の空気を除去でき
ず、パツケージの熱伝導度が低下したり、またこ
の細孔を無孔化するためにスプレードライヤーや
抵抗加熱炉で加熱すると粒子同志が融着したり、
焼結を起こすという不利がある。
そのため、このシリカを無孔化する方法が検討
されており、これについてはシリカ微粒子をスプ
レードライヤーを用いて造粒し、酸水素火炎中で
溶融する方法（特開昭60−131868号公報参照）、
シリカ微粒子含有ゾルを凍結乾燥し、ついで焼成
する方法（特開昭61−277527号公報参照）、アル
コキシシランの部分加水分解で得たシリカゾルを
噴霧乾燥し、ついで熱分解する方法（特開昭62−
176206号公報参照）が提案されている。
［発明が解決しようとする課題］
しかし、シリカの無孔化のために造粒後、酸水
素火炎で溶融する方法にはスプレードライヤーで
造粒すると粒度分布が広くなるし、これを酸水素
火炎で溶融すると粒子同志が融着して得られる粒
子の粒度分布がさらに広くなり、さらには工程が
長くなるという欠点があり、シリカゾルを凍結乾
燥し、焼成する方法には焼成工程での粒子の融着
を完全に抑えることができず、これも工程が長く
なるという不利がある。また、シリカゾルを噴霧
し、熱分解するという方法では得られる粒子の粒
径が噴霧時における液滴の径によつて決定される
ので粒度分布の広い粒子しか得られないという欠
点がある。
なお、このシリカ微粒子の無孔化についてはア
ルコキシシランの加水分解で得られたシリカ微粒
子を含む溶液を火炎中に導入することも提案され
ているが、これには火炎の熱によつて粒子同志が
融着することを避けることができないという不利
があり、この解決が望まれている。
［課題を解決するための手段］
本発明はこのような不利・欠点を解決した球状
シリカ微粒子およびその製造方法に関するもので
あり、これは多孔質度が1.0〜2.0であり、平均粒
径が0.2〜5.0μｍで、平均粒径の変動係数が0.15以
下であることを特徴とする球状微粒子シリカ、お
よびアルコキシシランを加水分解して得たシリカ
を火炎温度が500〜1300℃の火炎中で乾燥、無孔
化してなることを特徴とする前記球状シリカ微粒
子の製造方法に関するものである。
すなわち、本発明者らは粒度分布が狭く、無孔
質である球状シリカ微粒子の製造方法について
種々検討した結果、アルコキシシランを公知の加
水分解法で処理して得たシリカを火炎を処理して
無孔化する際に、この火炎の温度を余り高くせず
500〜1300℃のものとすればシリカ微粒子を融着
せずに無孔化し得ることを見出し、これによれば
粒度分布が狭く、無孔質とされた球状シリカ微粒
子を容易に、かつ効率的に得ることができること
を確認して本発明を完成させた。
以下にこれをさらに詳述する。
［作用］
本発明の球状シリカ微粒子はアルコキシシラン
を加水分解して得たシリカを火炎処理することに
よつて得ることができる。
このアルコキシシランの加水分解は公知の方法
で行えばよい。したがつてこのアルコキシシラン
は一般式Si（OR）4で示され、Ｒが炭素数１〜４の
アルキル基であるもの、例えばテトラメトキシシ
ラン、テトラエトキシシラン、テトラプロポキシ
シラン、テトラブトキシシランなどとすればよい
が、これらのうちでは高純度化が容易であり、安
価であるテトラメトキシシラン、テトラエトキシ
シランが好ましいものとされる。
このアルコキシシランの加水分解はこれまでに
提案されているいかなる方法で行なつてもよく、
したがつてこれはアルカリ性触媒、酸性触媒のい
ずれを使用してもよいし、この加水分解の際に添
加される有機溶媒の種類、量についても制限はな
い。しかし、後記する火炎処理において残渣、不
純物を発生するような物質は使用すべきではな
く、したがつて例えばアルカリ性触媒として
NaOHを使用すると火炎処理したあとにNaが残
留し、これが金属不純物となるのでこのようなも
のは使用してはならない。
この加水分解により得られるシリカ球状微粒子
については粒径が0.2μｍ以下であるとこの粒子の
熱容量が小さいために後記する火炎処理で融着し
てしまうし、これが5μｍ以上であるとその分散
性の調整が難しくなるので、これは反応条件を調
整して粒径が0.2〜5μｍのものとする必要がある
が、この反応条件についてはこのシリカが調整す
べき粒径となるように、そのアルコキシシランの
種類、量、添加する水の量、触媒の種類、量、有
機溶媒の種類、量をこれまで提案されている方法
にしたがつて決定すればよく、例えばテトラエト
キシシラン、アンモニア、水、エタノールを用い
て0.5μｍの球状シリカを得る場合には、前記した
公知例の処理によつてテトラエトキシシランを
0.28モル／、アノモニアを0.8モル／、水を
12.5モル／とすればよい。
このようにして得られたシリカスラリーは、つ
いで火炎処理によつて無孔化するのであるが、こ
れはシリカスラリーを火炎中に噴霧して処理すれ
ばよい。しかし、この火炎処理に当つては火炎の
温度が500℃以下では無孔化が完全に終了せず、
しかもスラリー中の有機溶剤の不完全燃焼によつ
てシリカ中に微量の炭素分が残留することにな
り、1300℃以上とするとシリカ粒子同志が融着し
ても分散性のよいシリカ球を得ることができなく
なるので、これは500〜1300℃の範囲とする必要
がある。この火炎温度はフイードされた可燃性成
分（可燃性ガス、スラリー中の有機溶媒など）の
燃焼により発生する熱量と、これらを顕熱、潜熱
として吸収するイナート成分の量により決定され
るため、これら可燃ガス、スラリー、イナートの
フイード量により調整すればよい。この火炎は酸
水素炎でもメタン−酸素炎であつてもよく、ここ
に使用する酸素ガスは必要量の70％未満とすると
スラリー中の有機溶媒、可燃性ガスの不完全燃焼
を招くので70％以上とすることが必要とされる
が、この燃焼ガスに窒素、ヘリウム、水などの水
活性成分を添加することは火炎温度を調整するこ
とから有用とされる。
この火炎中へのシリカスラリーの噴霧は液体噴
霧、超音波噴霧など従来公知の方法で行えばよ
く、火炎中に噴霧された液滴は火炎により瞬時に
乾燥され、これに含有されていた有機溶媒は燃焼
するので、上記した加水分解で得られた多孔質の
シリカはこの燃焼熱によつて無孔化されて容易
に、かつ効率よく無孔化された球状シリカ微粒子
となる。
このようにして得られた無孔質の球状シリカ微
粒子はこの火炎処理によつても火炎温度が500〜
1300℃とされているので融着せず、したがつて平
均粒径は上記した加水分解時の平均粒径0.2〜5μ
ｍのままのものとなる。
また、多孔質度は細孔のない球状シリカ微粒子
の比表面積As［m2／ｇ］が平均粒径をＤ［nm］と
すると式
AS＝2720／Ｄ ……(1)
で示されるし、Ｄの単位をμｍとすれば
AS＝2.72／Ｄ ……(2)
で示され、多孔質の球状シリカ微粒子は細孔が形
成する表面があるために細孔のない球状シリカ微
粒子よりもその比表面積が大きくなり、この細孔
による表面を含む実測の比表面積SA［m2／ｇ］と
上記した粒径より計算された理論値である比表面
積ASとの比が多孔質度Ｐとして表わされる。
Ｐ＝SA／AS ……(3)
したがつて、完全な無孔質球では実測される比
表面積は平坦な外皮表面分のみであるので、粒径
基準の理論比表面積（AS）と一致し、多孔質度
Ｐは1.0となる。一方、微細な細孔をもつ多孔質
球では実測される比表面積が外皮表面に加え、細
孔による表面を含むので、理論比表面積（AS）
より大きくなり、Ｐは1.0以上となる。上記した
加水分解により得られた球状シリカは多くの細孔
をもつものであることから、例えば粒径が0.5μｍ
のものはその実測比表面積SAが約50m2／ｇであ
り、このものの理論比表面積は上記(2)式からAS
＝2.72／0.5＝5.44となるので、このときのＰは
50／5.44＝9.19となるのである。このようにＰ値
が２以上では無孔化が不充分で充填剤として用い
た場合、問題が生じる。一方本発明の球状シリカ
微粒子は上記の条件の火炎処理で無孔質化されて
いるので実質的に細孔をもたないものとなり、そ
れ故に(3)式中のSAが減少し、Ｐ値も2.0以下のも
のとなり、充填剤としてすぐれたものとなる。
また、ここに得られた球状シリカ微粒子の粒径
のバラつき（単分散性）は標準偏差σと平均粒径
Ｄとの比で示される変動係数CVで表わされ、
CV＝σ／Ｄ ……(4)
このCVはバラつきの少ない程小さくなるが、
本発明の球状シリカ微粒子はアルコキシシランの
加水分解によつて得られた単分散性の良好な状態
のものがそのまま火炎処理によつて乾燥、無孔化
され、このものは融着することもないのでこの変
動係数CVは0.15以下と非常に小さいものになる。
［実施例］
つぎに本発明の実施例および比較例をあげる
が、例示した写真は走査型電子顕微鏡Ｔ−20［日
本電子(株)製］を用いて撮影した電子顕微鏡写真で
あり、この球状シリカ微粒子の平均粒径、標準偏
差はこの電子顕微鏡から測定したもの、また比表
面積はマイクロメテリツクス・フローソープ−
2300形［島津製作所(株)製］を用いて測定したもの
である。
実施例 １
温度計およびプロペラ型攪拌機を設けた５の
フラスコに、2.9％アンモニア水880ml、水410ml、
メタノール2086mlを仕込んで内温を20℃に保ち、
フラスコ内を600rpmで攪拌しながらここにテト
ラメトキシシラン68.4mlとメタノール440mlとの
混合溶液を75分かけて滴下し、滴下終了後も15分
間攪拌を行なつたところ、白色のスラリーが得ら
れ、このスラリーにはシリカ分7.0％、水20.9％、
メタノール67.0％、アンモニア5.1％が含まれて
いた。
ついで、このスラリーを酸素ガスと共に火炎温
度を1180℃に調整した酸水素火炎中に噴霧し、生
成した微粒子をバツグフイルターで捕集したとこ
ろ、白色のシリカ粉末を得られた。
なお、この火炎温度はバーナーに供給する水素
量および発生する燃焼熱を顕熱として奪うためバ
ーナーに供給するイナートとしてのN2ガス量に
より調整した。
つぎにこのシリカ粉末を電子顕微鏡で撮影した
ところ、第１図に示したものが得られ、これより
その平均粒径、標準偏差をしらべたところ、この
平均粒径は0.64μｍ、標準偏差は0.078μｍであり、
変動係数は0.122、またBET表面積は4.5m2／ｇで
その多孔質度は1.06であつた。
実施例２、比較例１〜２
実施例１で得られたスラリーを酸素ガスと共に
火炎温度を804℃（実施例２）、1380℃（比較例
１）、450℃（比較例２）に調整した酸水素火炎中
に噴霧して乾燥、無孔化処理し、生成した微粒子
をバツグフイルターで捕集したところ、実施例
２、比較例１では白色粉末が得られたが、比較例
２では薄茶色に着色した粉末が得られた。
つぎにこれらの粉末の電子顕微鏡写真を撮影し
たところ、実施例のものは第２図、比較例１のも
のは第３図、比較例２のものは第４図に示したと
おりのものとなり、これから測定したこれらの粉
末の平均粒径、標準偏差、および変動係数、なら
びに比表面積、多孔質度については第１表に示し
たとおりの結果が得られ、これより比較例１では
シリカの融着があり、比較例２では無孔化の完了
していないことが確認された。
[Industrial Field of Application] The present invention is made by drying silica particles obtained by hydrolyzing alkoxysilane with flame to make them non-porous.The present invention is suitable for use in plastic packaging because the particle size distribution is narrow and non-porous. The present invention relates to spherical silica fine particles useful as fillers and a method for producing the same. [Prior Art] Various methods are known for producing silica, and the silica obtained by hydrolyzing alkoxysilane has a narrow particle size distribution and is highly pure. The particle size was determined by dropping an alkoxysilane-alcohol solution into a NH 3 -H 2 O-alcohol solution containing ammonia.
Method for obtaining 0.02-1μm silica [J.Colloid
Interface Sci. 26 , 62 (1968)], by adding water and/or alcohol solutions to alkoxysilanes in the presence of an acidic catalyst such as hydrochloric acid to
Method for obtaining 500 μm silica (Japanese Patent Application Laid-Open No. 62-138335
(see Publication No.) is proposed. However, since the silica obtained by these methods has fine pores, the specific surface area determined by the BET method is
Since it is extremely large at 10 to 300 m 2 /g, if it is used as a filler for plastic packages such as ICs, the air in the pores cannot be removed, resulting in a decrease in the thermal conductivity of the package. When heated with a spray dryer or resistance heating furnace to make pores non-porous, particles may fuse together,
It has the disadvantage of causing sintering. Therefore, a method of making this silica non-porous is being considered, and one method is to granulate fine silica particles using a spray dryer and melt them in an oxyhydrogen flame (see Japanese Patent Laid-Open No. 131868/1986). ,
A method in which a sol containing fine silica particles is freeze-dried and then calcined (see JP-A-61-277527), a method in which a silica sol obtained by partial hydrolysis of alkoxysilane is spray-dried and then thermally decomposed (JP-A-62 −
176206) has been proposed. [Problems to be Solved by the Invention] However, in order to make silica non-porous, the method of granulating it and then melting it with an oxyhydrogen flame results in a wide particle size distribution when the silica is granulated with a spray dryer. If the silica sol is melted, the particles will fuse together, resulting in a wider particle size distribution, and the process will be longer. This has the disadvantage that it is not possible to completely suppress wear, and this also lengthens the process. Furthermore, the method of spraying silica sol and thermally decomposing it has the disadvantage that only particles with a wide particle size distribution can be obtained because the particle size of the particles obtained is determined by the diameter of the droplets at the time of spraying. In order to make these fine silica particles non-porous, it has been proposed to introduce a solution containing fine silica particles obtained by hydrolysis of alkoxysilane into a flame, but this method involves the heat of the flame causing the particles to become non-porous. There is a disadvantage that it is impossible to avoid fusion of the two, and a solution to this problem is desired. [Means for Solving the Problems] The present invention relates to spherical silica fine particles that solve these disadvantages and drawbacks, and a method for producing the same. Spherical fine particle silica characterized by ~5.0 μm and a coefficient of variation of average particle size of 0.15 or less, and silica obtained by hydrolyzing alkoxysilane are dried in a flame with a flame temperature of 500 to 1300°C. The present invention relates to a method for producing the spherical silica fine particles, which are made non-porous. That is, the present inventors have studied various methods for producing spherical silica particles that have a narrow particle size distribution and are non-porous. When making it non-porous, do not make the temperature of this flame too high.
It was discovered that silica fine particles could be made non-porous without being fused if heated to a temperature of 500 to 1,300°C. According to this, it was possible to easily and efficiently make spherical silica fine particles with a narrow particle size distribution and non-porous. The present invention was completed after confirming that it could be obtained. This will be explained in further detail below. [Function] The spherical silica fine particles of the present invention can be obtained by flame treating silica obtained by hydrolyzing alkoxysilane. Hydrolysis of this alkoxysilane may be carried out by a known method. Therefore, this alkoxysilane is represented by the general formula Si(OR) 4 and R is an alkyl group having 1 to 4 carbon atoms, such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Among these, tetramethoxysilane and tetraethoxysilane are preferred because they are easy to purify and are inexpensive. Hydrolysis of this alkoxysilane may be carried out by any method proposed so far.
Therefore, either an alkaline catalyst or an acidic catalyst may be used, and there are no restrictions on the type or amount of the organic solvent added during this hydrolysis. However, substances that generate residues and impurities during the flame treatment described later should not be used, and therefore, for example, as an alkaline catalyst.
If NaOH is used, Na will remain after flame treatment, and this will become a metal impurity, so such a substance should not be used. If the silica spherical fine particles obtained by this hydrolysis have a particle size of 0.2 μm or less, the particles will have a small heat capacity and will be fused during the flame treatment described later, while if the particle size is 5 μm or more, the dispersibility will be This makes adjustment difficult, so it is necessary to adjust the reaction conditions so that the particle size is 0.2 to 5 μm.However, regarding these reaction conditions, it is necessary to adjust the alkoxysilane so that the silica has the particle size that should be adjusted. The type and amount of silane, the amount of water to be added, the type and amount of catalyst, and the type and amount of organic solvent can be determined according to the methods proposed so far. For example, tetraethoxysilane, ammonia, water, ethanol, etc. When obtaining 0.5 μm spherical silica using
0.28 mol/, anomonia 0.8 mol/, water
The amount may be 12.5 mol/. The silica slurry thus obtained is then rendered non-porous by flame treatment, which can be done by spraying the silica slurry into a flame. However, in this flame treatment, if the flame temperature is below 500℃, the non-porous process will not be completed completely.
Moreover, due to incomplete combustion of the organic solvent in the slurry, a trace amount of carbon remains in the silica, so if the temperature is 1300°C or higher, even if the silica particles fuse together, silica spheres with good dispersion cannot be obtained. This needs to be in the range of 500 to 1300°C. This flame temperature is determined by the amount of heat generated by the combustion of the fed combustible components (combustible gas, organic solvent in slurry, etc.) and the amount of inert components that absorb these as sensible heat and latent heat. It may be adjusted by the feed amount of combustible gas, slurry, and inert. This flame may be an oxyhydrogen flame or a methane-oxygen flame, and if the oxygen gas used here is less than 70% of the required amount, it will lead to incomplete combustion of the organic solvent and flammable gas in the slurry, so 70% of the required amount of oxygen gas will be used. Although the above is required, it is considered useful to add water-active components such as nitrogen, helium, and water to the combustion gas because it adjusts the flame temperature. Spraying of the silica slurry into the flame can be carried out by conventionally known methods such as liquid spraying or ultrasonic spraying, and the droplets sprayed into the flame are instantly dried by the flame, and the organic solvent contained in the droplets is instantly dried by the flame. is combusted, the porous silica obtained by the above-mentioned hydrolysis is made non-porous by the heat of combustion, and easily and efficiently becomes non-porous spherical silica fine particles. The non-porous spherical silica fine particles obtained in this way have a flame temperature of 500 to
Since the temperature is said to be 1300℃, there is no fusion, and therefore the average particle size is 0.2 to 5μ during hydrolysis as described above.
It will remain as m. In addition, the degree of porosity is expressed by the formula A S = 2720/D (1) where the specific surface area As [m 2 /g] of spherical silica fine particles without pores and the average particle diameter D [nm]. , if the unit of D is μm, then A S = 2.72/D ...(2), and porous spherical silica particles have a surface with pores, so they are more difficult than spherical silica particles without pores. The specific surface area increases, and the ratio of the actually measured specific surface area S A [m 2 /g] including the surface due to these pores to the theoretical specific surface area A S calculated from the above particle size is the degree of porosity. Denoted as P. P=S A /A S ……(3) Therefore, since the actual measured specific surface area of a completely non-porous sphere is only the flat outer skin surface, the theoretical specific surface area based on particle size (A S ) , and the porosity P is 1.0. On the other hand, for porous spheres with fine pores, the actually measured specific surface area includes the surface due to pores in addition to the outer skin surface, so the theoretical specific surface area (A S )
becomes larger, and P becomes 1.0 or more. Since the spherical silica obtained by the above hydrolysis has many pores, the particle size is, for example, 0.5 μm.
The actual specific surface area S A of this material is approximately 50 m 2 /g, and the theoretical specific surface area of this material is A S
= 2.72/0.5 = 5.44, so P at this time is
50/5.44=9.19. As described above, when the P value is 2 or more, the non-porous property is insufficient and problems arise when used as a filler. On the other hand, since the spherical silica fine particles of the present invention are made non-porous by flame treatment under the above conditions, they have virtually no pores, so S A in formula (3) decreases, and P The value is also less than 2.0, making it an excellent filler. Furthermore, the variation in particle size (monodispersity) of the obtained spherical silica fine particles is expressed by the coefficient of variation C V , which is the ratio of the standard deviation σ and the average particle size D, and C V = σ/D. ...(4) This C V becomes smaller as there is less variation, but
The spherical silica particles of the present invention are obtained by hydrolyzing alkoxysilane and are in a good state of monodispersity, and are directly dried and made non-porous by flame treatment, and they do not fuse. Therefore, this coefficient of variation C V is very small, less than 0.15. [Example] Next, Examples and Comparative Examples of the present invention will be given. The illustrated photographs are electron micrographs taken using a scanning electron microscope T-20 [manufactured by JEOL Ltd.] The average particle diameter and standard deviation of silica fine particles were measured using this electron microscope, and the specific surface area was determined by Micrometries Flow Soap.
Measured using Model 2300 [manufactured by Shimadzu Corporation]. Example 1 880 ml of 2.9% ammonia water, 410 ml of water,
Pour 2086ml of methanol and keep the internal temperature at 20℃.
While stirring the inside of the flask at 600 rpm, a mixed solution of 68.4 ml of tetramethoxysilane and 440 ml of methanol was dripped into the flask over 75 minutes, and when stirring was continued for 15 minutes after the dropwise addition, a white slurry was obtained. This slurry contains 7.0% silica, 20.9% water,
It contained 67.0% methanol and 5.1% ammonia. Next, this slurry was sprayed together with oxygen gas into an oxyhydrogen flame whose flame temperature was adjusted to 1180°C, and the generated fine particles were collected with a bag filter to obtain white silica powder. Note that this flame temperature was adjusted by the amount of hydrogen supplied to the burner and the amount of N 2 gas as an inert supplied to the burner in order to remove the generated combustion heat as sensible heat. Next, when this silica powder was photographed with an electron microscope, the one shown in Figure 1 was obtained. From this, the average particle size and standard deviation were investigated, and the average particle size was 0.64 μm, and the standard deviation was 0.078. μm,
The coefficient of variation was 0.122, the BET surface area was 4.5 m 2 /g, and the porosity was 1.06. Example 2, Comparative Examples 1 to 2 The slurry obtained in Example 1 was mixed with oxygen gas and the flame temperature was adjusted to 804°C (Example 2), 1380°C (Comparative Example 1), and 450°C (Comparative Example 2). When sprayed into an oxyhydrogen flame, dried, and treated to make it non-porous, the generated fine particles were collected using a bag filter. In Example 2 and Comparative Example 1, a white powder was obtained, but in Comparative Example 2, a light brown powder was obtained. A colored powder was obtained. Next, electron micrographs of these powders were taken, and the results were as shown in Figure 2 for Example, Figure 3 for Comparative Example 1, and Figure 4 for Comparative Example 2. The average particle diameter, standard deviation, coefficient of variation, specific surface area, and porosity of these powders measured from now on were as shown in Table 1. It was confirmed that in Comparative Example 2, the pore-free formation was not completed.
【表】【table】
【表】
［発明の効果］
本発明は前記したように、多孔質度が1.0〜2.0
であり、平均粒径が0.2〜5.0μｍで、平均粒径の
変動係数が0.15である球状シリカ微粒子およびア
ルコキシシランの加水分解で得たシリカを500〜
1300℃の火炎の中で乾燥、無孔化した上記した球
状シリカ微粒子の製造方法に関するものである
が、この球状シリカ微粒子は実質的に無孔質化さ
れているのでプラスチツクパツケージ用充填剤と
して有用とされるものであり、この製造方法によ
れば目的とする球状シリカ微粒子を容易にかつ効
率的に得ることができるという有利性が与えられ
る。[Table] [Effects of the invention] As described above, the present invention has a porosity of 1.0 to 2.0.
Spherical silica fine particles with an average particle size of 0.2 to 5.0 μm and a coefficient of variation of the average particle size of 0.15 and silica obtained by hydrolysis of alkoxysilane are
This relates to a method for producing the above-mentioned spherical silica fine particles that are dried in a flame at 1300°C and made non-porous.Since these spherical silica fine particles are substantially non-porous, they are useful as fillers for plastic packaging. This production method has the advantage that the desired spherical silica fine particles can be obtained easily and efficiently.
第１図は本発明の実施例１で得られた球状シリ
カ微粒子の構造を示す電子顕微鏡写真、第２図は
本発明の実施例２で得られた球状シリカ微粒子の
構造を示す電子顕微鏡写真、第３図は比較例１で
得られた球状シリカ微粒子の構造を示す電子顕微
鏡写真、第４図は比較例２で得られた球状シリカ
微粒子の構造を示す電子顕微鏡写真である。
FIG. 1 is an electron micrograph showing the structure of spherical silica fine particles obtained in Example 1 of the present invention, FIG. 2 is an electron micrograph showing the structure of spherical silica fine particles obtained in Example 2 of the present invention, FIG. 3 is an electron micrograph showing the structure of the spherical silica fine particles obtained in Comparative Example 1, and FIG. 4 is an electron micrograph showing the structure of the spherical silica fine particles obtained in Comparative Example 2.
Claims (1)
5.0μｍで、平均粒径の変動係数が0.15以下である
ことを特徴とする球状シリカ微粒子。 ２ アルコキシシランを加水分解して得た微細球
状シリカを含む溶液を火炎温度が500〜1300℃の
火炎中で乾燥、無孔化してなることを特徴とする
請求項１に記載の球状シリカ微粒子の製造方法。[Claims] 1. The porosity is 1.0 to 2.0, and the average particle size is 0.2 to 2.0.
Spherical silica fine particles having a mean particle size of 5.0 μm and a coefficient of variation of 0.15 or less. 2. The spherical silica fine particles according to claim 1, which are obtained by drying a solution containing fine spherical silica obtained by hydrolyzing alkoxysilane in a flame at a flame temperature of 500 to 1300°C to make it non-porous. Production method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11909289A JPH02296711A (en) | 1989-05-12 | 1989-05-12 | Spherical silica particle and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11909289A JPH02296711A (en) | 1989-05-12 | 1989-05-12 | Spherical silica particle and its production |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02296711A JPH02296711A (en) | 1990-12-07 |
| JPH0470257B2 true JPH0470257B2 (en) | 1992-11-10 |
Family
ID=14752702
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11909289A Granted JPH02296711A (en) | 1989-05-12 | 1989-05-12 | Spherical silica particle and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02296711A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5879794A (en) * | 1994-08-25 | 1999-03-09 | W. L. Gore & Associates, Inc. | Adhesive-filler film composite |
| DE19920794A1 (en) * | 1999-05-06 | 2000-11-09 | Merck Patent Gmbh | Process for the preparation of bead polymers |
| KR100793503B1 (en) | 2000-09-27 | 2008-01-14 | 미츠비시 레이온 가부시키가이샤 | Non-porous spherical silica and method for production thereof |
| US7749429B2 (en) | 2004-09-14 | 2010-07-06 | Japan Science And Technology Agency | Ceramic particle group and method for production thereof and use thereof |
| FR2936515B1 (en) * | 2008-09-30 | 2011-08-05 | Saint Gobain Ct Recherches | ZIRCONIUM OXIDE POWDER |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6272514A (en) * | 1985-09-25 | 1987-04-03 | メルク・パテント・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Spherical sio2 particle |
| JPS63310714A (en) * | 1988-06-07 | 1988-12-19 | Tokuyama Soda Co Ltd | Silica particles |
| JPH01145317A (en) * | 1987-12-01 | 1989-06-07 | Nippon Shokubai Kagaku Kogyo Co Ltd | Production of spherical fine particle of silica |
| JPH02288A (en) * | 1987-12-18 | 1990-01-05 | Beecham Group Plc | Substituted penem derivative |
-
1989
- 1989-05-12 JP JP11909289A patent/JPH02296711A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6272514A (en) * | 1985-09-25 | 1987-04-03 | メルク・パテント・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Spherical sio2 particle |
| JPH01145317A (en) * | 1987-12-01 | 1989-06-07 | Nippon Shokubai Kagaku Kogyo Co Ltd | Production of spherical fine particle of silica |
| JPH02288A (en) * | 1987-12-18 | 1990-01-05 | Beecham Group Plc | Substituted penem derivative |
| JPS63310714A (en) * | 1988-06-07 | 1988-12-19 | Tokuyama Soda Co Ltd | Silica particles |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02296711A (en) | 1990-12-07 |
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