JP3647929B2 - Method for producing conductive antimony-containing tin oxide fine powder - Google Patents
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Description
【０００１】
【産業上の利用分野】
本発明は、優れた導電性と優れた透明性を示す導電性アンチモン含有酸化錫微粉末の製造方法に関する。本発明の導電性微粉末は、非常に微細な粉末であり、プラスチック、ゴム、塗料などの媒体に混入、配合されても可視光線を透過させるので、これらの媒体の色調、透明性を損なうことなく導電性を付与することができる。本発明の方法によって得られる導電性微粉末は、前記特性を利用して、化学繊維、プラスチックフィルムなどへの透明性を有した帯電防止剤として、また静電記録紙、導電性塗料などへの導電性および透明性付与剤として利用される。本発明の導電性微粉末は、水性媒体における分散安定性が優れ、ゼラチン、ポリビニルアルコール、水溶性アクリル樹脂などを媒体とする水系塗料用の導電性微粉末としても有用である。
【０００２】
【従来の技術】
アンチモン含有導電性酸化錫粉末は、電子伝導型の導電性機能を呈するところから高分子電解質などのいわゆるイオン伝導型のものに比べ、湿度や温度に対する導電性の安定性が高く、かつ透明性を有するところから近年例えば、塗料、プラスチック、ゴム、繊維などの種々の分野での素材や製品の導電性付与剤としての利用が注目され、急速に適用が図られつつある。
このような粉末の製造方法としては、例えば、加熱水中に、アルコール、塩酸水溶液およびアセトンのうちの１種または２種以上の混合液に塩化錫および塩化アンチモンを溶解した溶液を加えて加水分解する方法（特開昭56-156606 号）、この特開昭56-156606 号の方法において、アルカリを加えてpH８以上に維持して反応させる方法（特開昭57-71822号）などがある。
【０００３】
【発明が解決しようとする課題】
前記従来法で得られるアンチモンを含有した導電性酸化錫微粉末は、例えばプラスチック、ゴム、塗料などの種々の適用媒体での混入、配合系において、優れた可視光の透過性を有するので、これらの種々の適用媒体の透明性を損なうことなく導電性を付与することができるものである。しかしながら、前記導電性酸化錫粉末の粉体色は、青黒い色調となり易く、これがためこのものを使用した前記種々の適用系において青味色調や暗色化を惹起し易いという欠点がある。その為、各種媒体への配合量を少なくしたり、塗料の場合にあっては、塗布膜厚を薄くしたり、更には該導電性酸化錫粉末のアンチモン含有量の低減といった方法が採用されているが、これらの方法はいずれも適用媒体系での導電性付与特性を著しく損なうものであり、従って、適用媒体系における導電性、透明性、色調の三つの特性を、ともに十分満足させることができず、その解決が強く希求されている。
【０００４】
【課題を解決するための手段】
本発明者等は、アンチモンを含有した導電性酸化錫微粉末において、前記課題の導電性、透明性を損なわずに青味色調化の低減を図るべく、塩化錫及び塩化アンチモンの溶液の加水分解反応、中和反応などの条件について、詳細に検討を進めた結果、従来より実施されている錫化合物とアンチモン化合物の溶液を中和して酸化錫、酸化アンチモンの水和物の共沈物を得、次いでこのものを焼成する方法に代えて、錫化合物の溶液を中和して酸化錫の水和物を生成させ、次いで該生成物の表面にアンチモン化合物の溶液を中和して酸化アンチモンの水和物を生成させた後分別し、焼成することによって、意外にも青味が非常に少ない導電性アンチモン含有酸化錫微粉末を得ることができること、さらに、前記酸化錫の水和物を生成させる工程及び酸化アンチモンの水和物を生成させる工程の少なくともいづれかの工程においてケイ素化合物を付加処理させることにより、得られる導電性酸化錫微粉末の水性媒体系における分散性及びその安定性を一層優れたものとし得ることの知見を得、これに基づいて本発明を完成したのである。
【０００５】
すなわち、本発明は、
１．塩化錫の溶液とアルカリ水溶液とを水中に並行的に添加し、中和反応液のｐＨを３以上に保持しながら中和して酸化錫の水和物を生成させ、次いで該生成物の水中に塩化アンチモンの溶液とアルカリ水溶液とを並行的に添加し、中和反応液のｐＨを３以上に保持しながら中和して該生成物の表面に酸化アンチモンの水和物を生成させ、しかる後焼成することを特徴とする重量平均粒子径が０．１μｍ以下、粉体色カラーのｂ値が−１０以上でＬ値が３５以上、及び粉体抵抗が１ＫΩｃｍ以下である導電性アンチモン含有酸化錫微粉末の製造方法、
２．酸化錫の水和物を生成させる工程及び酸化アンチモンの水和物を生成させる工程の少なくともいづれかの工程においてケイ素化合物を存在させることを特徴とする導電性アンチモン含有酸化錫微粉末の製造方法である。
【０００６】
本発明の方法によって得られる導電性アンチモン含有酸化錫微粉末は、重量平均粒子径が０．１μｍ以下、粉体色カラーのｂ値が−１０以上でＬ値が３５以上、及び粉体抵抗が１ＫΩｃｍ以下の特性を有するものであり、このものは、錫化合物の溶液を中和して酸化錫の水和物を生成させ、次いで該生成物の表面にアンチモン化合物の溶液を中和して酸化アンチモンの水和物を生成させ、しかる後焼成することによって調製し得る。しかして、ここで用いられる錫化合物としては、塩化第一錫、塩化第二錫などのハロゲン化錫、或いは、酢酸錫、蓚酸錫、硫酸錫、硝酸錫などの錫の有機或いは無機酸塩（第一錫塩、第二錫塩）、錫酸カリウム、錫酸ナトリウムなどの錫酸アルカリ塩などが挙げられ、これらを単独で或いは２種以上混合して用いてもよい。中でも塩化錫の塩酸水溶液を用いるのが、工業的にも望ましい。
【０００７】
アンチモン化合物としては、塩化アンチモンなどのハロゲン化アンチモン、或いは、アンチモンの硫酸塩などの無機酸塩などが挙げられ、これらを単独で或いは２種以上混合して用いてもよい。中でも塩化アンチモンの塩酸水溶液を用いるのが、工業的にも望ましい。
酸化アンチモンの添加量は、酸化錫に対して１〜３０重量％、望ましくは５〜２０重量％である。
【０００８】
ケイ素化合物としては、塩化ケイ素の他に、ケイ酸カリウム、ケイ酸ナトリウムなどの可溶性ケイ酸塩を使用することができる。塩化ケイ素を使用する場合は、アルコール、塩酸水溶液およびアセトンのうちの１種または２種以上の溶液または混合液に０．１〜１００ｇ／ｌの塩化ケイ素を溶解した溶液として使用するのが望ましく、また可溶性ケイ酸塩の場合はそれらの水溶液を使用するのが良い。塩化ケイ素の代わりにシリカゾルを使用することもできる。更には各種シランカップリング剤、シリコーンオイル、コロイダルシリカ等も使用し得る。
ケイ素化合物として塩化ケイ素を使用する場合は、塩化錫或いは塩化アンチモンの各溶液と混合して或いは混合せずに単独の溶液として添加することもできる。またケイ素化合物として可溶性ケイ酸塩を使用する場合には、単独の溶液として或いはアルカリ溶液に溶解した溶液として添加することができる。
酸化ケイ素の添加量は、酸化錫に対して６重量％以下、望ましくは４重量％以下である。
【０００９】
本発明方法においてはまず、塩化錫の溶液をアルカリで中和して酸化錫の水和物を生成させる。次いで、塩化アンチモンの溶液をアルカリで中和して酸化アンチモンの水和物を生成させる。
【００１０】
また、塩化錫及び塩化アンチモンの各溶液の中和反応は、例えば、(a) 塩化錫或いは塩化アンチモンの各溶液とアルカリ水溶液とを熱水中に並行的に添加して中和する、(b) 塩化錫或いは塩化アンチモンの各溶液中にアルカリ水溶液を添加して中和する、(c) アルカリ水溶液中に塩化錫或いは塩化アンチモンの各溶液を添加して中和する、などの方法が挙げられる。このような方法の中でも特に(a) の方法が工業的には望ましく、この場合中和反応液のpHを３以上、望ましくは５〜10に保持するように行うのがよい。
【００１１】
さらに、ケイ素化合物を、酸化錫の水和物を生成させる工程及び酸化アンチモンの水和物を生成させる工程の少なくともいづれかの工程において存在させる場合には、例えば（１）酸化錫の水和物と酸化ケイ素の水和物との共沈物を生成させるように添加したり、（２）酸化錫の水和物を生成させた後、その上に酸化ケイ素の水和物を生成させるように添加したり、（３）酸化アンチモンの水和物と酸化ケイ素の水和物との共沈物を生成させるように添加したり、（４）酸化アンチモンの水和物を生成させた後、その上に酸化ケイ素の水和物を生成させるように添加したりする。
【００１２】
本発明方法においては、中和反応を加熱下に或いは熱水中で行うことが望ましいが、加熱することなく室温下に実施することもできる。
中和剤として使用するアルカリ水溶液としては、水酸化ナトリウム、水酸化カリウム、炭酸ナトリウム、炭酸カリウムなどのアルカリ金属の水酸化物、炭酸塩やアンモニアなどが、また、酸性水溶液としては、塩酸、硫酸などの鉱酸が挙げられ、これらは各々単独で或いは２種以上混合して用いてもよい。
【００１３】
本発明方法においては、次に、中和反応終了後の反応液から生成物を濾過し、必要に応じて洗浄して回収する。この場合、中和反応終了後の反応液に酸を加えて反応液のpHを５以下、望ましくは２〜４に調整した後、生成物を濾過するようにするのが望ましい。中和剤としてアルカリ金属の水酸化物や炭酸塩を使用する場合は、洗浄不足でアルカリ金属が該生成物に吸着し、残存すると後記の焼成工程でアルカリ金属が、SbのSnO2結晶中への固溶を妨害するので、SbをSnO2結晶中へ固溶させる場合には、アルカリ金属が残存しないように十分な洗浄を行う必要がある。また、酸化錫の水和物を生成させる工程で、中和により発生した塩は、洗浄により取り除いた後、酸化アンチモンの水和物を生成させる工程に供するのが望ましい。
【００１４】
回収した生成物は、その後必要に応じて乾燥した後 400〜800 ℃、望ましくは 500〜700 ℃の温度で焼成する。本発明方法においては、沈澱中に酸化ケイ素（含水物）が含まれている場合は、焼成時に、このケイ素化合物が粒子の焼結を抑制し、より微細な粒子が得られる。焼成時間は30分〜５時間が適当である。焼成後常法に従って乾燥、粉砕処理を施して導電性微粉末とする。
【００１５】
本発明の導電性アンチモン含有酸化錫微粉末は、プラスチックス、ゴム、繊維などに導電性付与材或いは基体として配合し、導電性樹脂組成物、導電性塗料組成物、磁性塗料、導電性ゴム、導電性繊維などの導電性組成物として利用することができる。
【００１６】
導電性樹脂組成物として利用する場合には、いわゆる汎用プラスチックス、エンジニアリングプラスチックスの種々のものを使用し得るが、汎用プラスチックスとしては、例えばポリエチレン、塩化ビニル樹脂、ポリスチレン、ポリプロピレン、メタクリル樹脂、ユリア・メラミン樹脂が、エンジニアリングプラスチック的汎用プラスチックスとしては、例えばフェノール樹脂、不飽和ポリエステル樹脂、硬質塩化ビニル樹脂、ＡＢＳ樹脂、ＡＳ樹脂が、エンジニアリングプラスチックとしては、例えばエポキシ樹脂、ポリアセタール、ポリカーボネート、ポリブチレンテレフタレート、ポリエチレンテレフタレート、ポリフェニレンエーテル、ポリフェニレンサルファイド、ポリスルホン、フッ素樹脂が、また、スーパーエンジニアリングプラスチックとしては、例えばジアリルフタレート樹脂、シリコン樹脂、ポリイミド樹脂、ポリアミドイミド、ビスマレイミドトリアジン、ポリアミノビスマレイミド、オレフィンビニルアルコール共重合体、ポリオキシベンジレン、ポリメチルペンテン、ポリエーテルサルホン、ポリエーテルイミド、ポリアリレート、ポリエーテルエーテルケトンなどが挙げられ、これらの樹脂に配合される。導電性アンチモン含有酸化錫微粉末の前記成形樹脂への配合量は、該樹脂１００重量部に対して３〜２００重量部、望ましくは１０〜１００重量部である。
【００１７】
本発明の導電性アンチモン含有酸化錫微粉末を、導電性塗料組成物或いは磁性塗料組成物として利用する場合には、種々のバインダー例えばポリビニルアルコール樹脂、塩ビ−酢ビ樹脂、アクリル樹脂、エポキシ樹脂、ウレタン樹脂、アルキッド樹脂、ポリエステル樹脂、エチレン酢酸ビニル共重合体、アクリル−スチレン共重合体、繊維素樹脂、フェノール樹脂、アミノ樹脂、フッ素樹脂、シリコーン樹脂、石油樹脂、セラック、ロジン誘導体、ゴム誘導体などの天然系樹脂などに配合され、水または溶媒中で分散される。導電性アンチモン含有酸化錫微粉末のバインダー樹脂への配合量は、バインダー固形分１００重量部に対して３〜２００重量部、望ましくは１０〜１００重量部である。導電性塗料組成物の場合には、該塗料を紙や高分子フィルムなどの絶縁性基体に塗布することにより、該基体上に軽くて透明性や表面平滑性、さらには密着性に優れた導電性塗膜を形成させて、種々の静電防止塗膜、静電記録紙、電子写真複写紙などとすることができる。
【００１８】
なお、本発明の方法によって得られる導電性アンチモン含有酸化錫微粉末を、水性系塗料に適用する場合に、該酸化錫微粉末を湿式粉砕処理して水性分散体を調製し、このものを塗料化に供する場合には、塗料化時の分散エネルギーの軽減を図る上で極めて好ましいものである。前記水性分散体の固形分濃度は１〜７０重量％、望ましくは１０〜５０重量％で、ｐＨは４〜１２、望ましくは５〜１０である。
【００１９】
このようにして得られた導電性組成物は、従来の方法により得られたアンチモン含有酸化錫微粉末を含有する導電性組成物と比較して、優れた導電性、透明性を有すると共に、従来にない青味色調の小さい（低減された）ものである。
【００２０】
【実施例】
実施例１
９０℃の純水５ｌ中に、塩化第二錫５水塩５００ｇを、３Ｎ塩酸水溶液５００ｍｌに溶解した溶液と、水酸化ナトリウム溶液とを、系のｐＨを７〜７．５に維持するように２０分間にわたって並行添加し、酸化錫の水和物の沈澱物を生成させた。次いで、ここへ塩酸を加えて系のｐＨを３に調整した後、該沈澱物を濾過し、その後濾液の比抵抗が２００００Ωｃｍになるまで水洗した。得られたケーキを純水５ｌにレパルプし、９０℃に加温後、三塩化アンチモン３７．０ｇを、３Ｎ塩酸水溶液３００ｍｌに溶解した溶液と、水酸化ナトリウム溶液とを、系のｐＨを７〜７．５に維持するように２０分間にわたって並行添加し、酸化錫の水和物上に酸化アンチモンの水和物を沈着させた。その後、塩酸を加えて系のｐＨを３に調整し、濾過し、その後濾液の比抵抗が２００００Ωｃｍになるまで水洗した。得られたケーキを電気炉で６００℃にて４時間焼成し、パルベライザーで粉砕して、比表面積４６．０ｍ2 ／ｇ、粉体抵抗４．６Ωｃｍの導電性微粉末を得た。粉体色カラー（プレス圧力２００Ｋｇ／ｃｍ2 ）のｂ値は−５．８、Ｌ値は５３．４であった。
【００２１】
比較例１
９０℃の純水５ｌ中に、塩化第二錫５水塩５００ｇ及び三塩化アンチモン３７．０ｇを、３Ｎ塩酸水溶液５００ｍｌに溶解した溶液と、２００ｇ／ｌの水酸化ナトリウム溶液とを、系のｐＨを７〜７．５に維持するように２０分間にわたって並行添加して酸化錫と酸化アンチモンの水和物の共沈物を生成させた。次にここへ塩酸を加えて系のｐＨを３に調整した後、該沈澱物を濾過し、その後濾液の比抵抗が２００００Ωｃｍになるまで水洗した。得られたケーキを電気炉で６００℃にて４時間焼成し、パルベライザーで粉砕して、比表面積４６．１ｍ2 ／ｇ、粉体抵抗２．０Ωｃｍの導電性微粉末を得た。粉体色カラー（プレス圧力２００Ｋｇ／ｃｍ2 ）のｂ値は−１２．０、Ｌ値は２４．０であった。
【００２２】
実施例２
９０℃の純水５ｌ中に、塩化第二錫５水塩５００ｇを、３Ｎ塩酸水溶液５００ｍｌに溶解した溶液と、ケイ酸ナトリウム水溶液（ＳｉＯ2 として３０８ｇ）１７．４ｍｌと水酸化ナトリウム水溶液とを、系のｐＨを７〜７．５に維持するように２０分間にわたって並行添加して共沈物を生成させた。次いで、ここへ塩酸を加えて系のｐＨを３に調整した後、該共沈物を濾過し、その後濾液の比抵抗が２００００Ωｃｍになるまで水洗した。得られたケーキを純水５ｌにレパルプし、９０℃に加温後、三塩化アンチモン３７．０ｇを、３Ｎ塩酸水溶液３００ｍｌに溶解した溶液と、水酸化ナトリウム溶液とを、系のｐＨを７〜７．５に維持するように２０分間にわたって並行添加し、酸化錫と酸化ケイ素の水和物の共沈物上に酸化アンチモンの水和物を沈着させた。その後、塩酸を加えて系のｐＨを３に調整し、濾過し、濾液の比抵抗が２００００Ωｃｍになるまで水洗した。得られたケーキを電気炉で６００℃にて４時間焼成し、パルベライザーで粉砕して、比表面積７７．５ｍ2 ／ｇ、粉体抵抗２．６Ωｃｍの導電性微粉末を得た。粉体色カラー（プレス圧力２００Ｋｇ／ｃｍ2 ）のｂ値は−７．８、Ｌ値は４１．０であった。
【００２３】
比較例２
９０℃の純水５ｌ中に、塩化第二錫５水塩５００ｇ及び三塩化アンチモン３７．０ｇを、３Ｎ塩酸水溶液５００ｍｌに溶解した溶液と、ケイ酸ナトリウム水溶液（ＳｉＯ2 として３０８ｇ）１７．４ｍｌと水酸化ナトリウム溶液とを、系のｐＨを７〜７．５に維持するように２０分間にわたって並行添加して酸化錫と酸化アンチモンと酸化ケイ素の水和物の共沈物を生成させた。次にここへ塩酸を加えて系のｐＨを３に調整した後、該共沈物を濾過し、その後濾液の比抵抗が２００００Ωｃｍになるまで水洗した。得られたケーキを電気炉で６００℃にて４時間焼成し、パルベライザーで粉砕して、比表面積７５．０ｍ2 ／ｇ、粉体抵抗１．９Ωｃｍの導電性微粉末を得た。粉体色カラー（プレス圧力２００Ｋｇ／ｃｍ2 ）のｂ値は−１３．０、Ｌ値は３２．０であった。
【００２４】
試験例１（粉体抵抗の評価）
試料粉末を１００Ｋｇ／ｃｍ2 の圧力で成型して円柱状圧粉体（直径１８ｍｍ、厚さ３ｍｍ）とし、その直流抵抗を測定して、下記の式から粉体抵抗（Ωｃｍ）を求めた。
粉体抵抗＝測定値×２．５４ (電極定数) ／厚さ（ｃｍ）
試料０．１〜０．２ｇを採取し、１５０℃で３０分間窒素ガス中で脱気した。その後、比表面積測定装置 （フローソーブ2300形、マイクロメリティック社製）を用い、窒素／ヘリウム混合ガス系でＢＥＴ法により比表面積を測定した。
【００２５】
試験例２（粉体色カラーの測定）
試料粉末を２００Ｋｇ／ｃｍ2 の圧力で成型して円柱状圧粉体（直径３３ｍｍ、厚さ５ｍｍ）とし、粉体色カラー（カラーコンピューター、ＳＭ−７−ＩＳ−２Ｂ型、スガ試験機製）を測定した。
【００２６】
試験例３
実施例１及び２と、比較例１及び２で得られた試料の導電性微粉末各２０ｇを、アクリル樹脂（アクリディックＡ−165 −45、固形分４５重量％、大日本インキ化学工業製）３０．６ｇ、トルエン−ブタノール混合溶液（混合重量比１：１）２６．４ｇ及びガラスビーズ５０ｇと混合した後ペイントシェーカー（レッドデビル（Red devil ）社、＃5110）に入れて２０分間振とうしてそれぞれのミルベースを調製した。
次に、各ミルベースに上記アクリル樹脂及び上記トルエン−ブタノール混合溶液をそれぞれ所定量加え、攪拌、混合して表１の各顔料濃度（重量％）塗料を調製した。この塗料をポリエステルフィルム及び白チャート紙に乾燥膜厚が４μm となるように塗布し、４０時間自然乾燥して試験シートを作成した。ポリエステルフィルムシートについて、表面抵抗率（Ω／□）を測定（デジタルオームメーター：Ｒ−５０６型、川口電気製作所製）し、白チャート紙シートについて、カラー（カラーコンピューター、ＳＭ−７−ＩＳ−２Ｂ型、スガ試験機製）を測定した。
また、ヘイズ度（％）を測定した（ヘイズメーター：ＮＤＨ−３００Ａ型、日本電色工業製）。これらの結果を表１及び表２に示す。
【００２７】
【表１】
【表２】
【発明の効果】
表１及び表２からも明らかなように、本発明によれば、透明性、導電性に優れ、かつ青味色調の小さな導電性アンチモン含有酸化錫微粉末を、工業的有利に製造することができる。[0001]
[Industrial application fields]
The present invention relates to a method for producing a conductive antimony-containing tin oxide fine powder exhibiting excellent conductivity and excellent transparency. The conductive fine powder of the present invention is a very fine powder, and transmits visible light even if mixed or blended in a medium such as plastic, rubber, paint, etc., so that the color tone and transparency of these mediums are impaired. Conductivity can be imparted. The conductive fine powder obtained by the method of the present invention can be used as an antistatic agent having transparency to chemical fibers, plastic films, etc., and to electrostatic recording paper, conductive paint, etc. It is used as a conductivity and transparency imparting agent. The conductive fine powder of the present invention has excellent dispersion stability in an aqueous medium, and is also useful as a conductive fine powder for water-based paints using gelatin, polyvinyl alcohol, water-soluble acrylic resin, or the like as a medium.
[0002]
[Prior art]
The antimony-containing conductive tin oxide powder exhibits an electronic conductivity type conductive function, and therefore has higher conductivity stability against humidity and temperature and transparency than a so-called ion conductive type such as a polymer electrolyte. In recent years, for example, its use as a conductivity-imparting agent for materials and products in various fields such as paints, plastics, rubbers, and fibers has attracted attention, and is being rapidly applied.
As a method for producing such a powder, for example, a solution in which tin chloride and antimony chloride are dissolved in one or a mixture of two or more of alcohol, an aqueous hydrochloric acid solution and acetone is added to heated water for hydrolysis. There are a method (JP-A-56-156606) and a method of JP-A-56-156606 in which an alkali is added and the reaction is carried out while maintaining the pH at 8 or more (JP-A-57-71822).
[0003]
[Problems to be solved by the invention]
The conductive tin oxide fine powder containing antimony obtained by the above-mentioned conventional method has excellent visible light permeability in mixing and compounding systems in various application media such as plastics, rubbers and paints. Thus, conductivity can be imparted without impairing the transparency of various application media. However, the powder color of the conductive tin oxide powder tends to have a bluish black color tone, and thus has the disadvantage that it tends to cause a bluish color tone and darkening in the various application systems using this. Therefore, methods such as reducing the compounding amount in various media, reducing the coating film thickness in the case of paint, and further reducing the antimony content of the conductive tin oxide powder are adopted. However, all of these methods significantly impair the conductivity imparting characteristics in the applied medium system, and therefore, the three characteristics of conductivity, transparency, and color tone in the applied medium system can be sufficiently satisfied. It cannot be done, and the solution is strongly demanded.
[0004]
[Means for Solving the Problems]
In the conductive tin oxide fine powder containing antimony, the present inventors hydrolyzed a solution of tin chloride and antimony chloride in order to reduce the blue tint without impairing the conductivity and transparency of the above problems. As a result of detailed investigations on the conditions such as reaction and neutralization reaction, the solution of tin compound and antimony compound, which has been conventionally used, is neutralized to produce a coprecipitate of tin oxide and antimony oxide hydrate. Then, instead of the method of firing this, the tin compound solution is neutralized to produce a tin oxide hydrate, and then the antimony compound solution is neutralized on the surface of the product to obtain antimony oxide. It is possible to obtain a conductive antimony-containing tin oxide fine powder with a surprisingly little bluish color by separating and baking after forming the hydrate of Process to be generated and The dispersibility and the stability of the conductive tin oxide fine powder in the aqueous medium system are further improved by subjecting the silicon compound to an addition treatment in at least one of the steps of forming a hydrate of antimony oxide. Based on this, the present invention was completed.
[0005]
That is, the present invention
1. Concurrently in adding a solution and an alkaline aqueous solution of tin chloride in water, neutralized by generating a hydrate of tin oxide, while maintaining the pH of the neutralization reaction solution 3 above, followed by water of the product An antimony chloride solution and an alkaline aqueous solution are added in parallel to the solution, and neutralized while maintaining the pH of the neutralization reaction solution at 3 or more to produce antimony oxide hydrate on the surface of the product. Conductive antimony-containing oxide having a weight average particle size of 0.1 μm or less, a powder color b value of −10 or more, an L value of 35 or more, and a powder resistance of 1 KΩcm or less, characterized by post-baking Production method of tin fine powder,
2. A conductive antimony-containing tin oxide fine powder production how, characterized in that the presence of a silicon compound in at least Izure or process of the process to produce a hydrate of steps and antimony oxide to produce a hydrate of tin oxide is there.
[0006]
The conductive antimony-containing tin oxide fine powder obtained by the method of the present invention has a weight average particle size of 0.1 μm or less, a powder color b value of −10 or more, an L value of 35 or more, and a powder resistance. It has a characteristic of 1 KΩcm or less, and this product neutralizes a tin compound solution to form a tin oxide hydrate, and then neutralizes the antimony compound solution on the surface of the product to oxidize. It can be prepared by forming antimony hydrate and then calcining. Thus, as the tin compound used herein, stannous chloride, tin halides, such as stannic chloride, Or, tin acetate, oxalate, tin, organic or inorganic acids of tin such as tin sulfate, tin nitrate Examples thereof include salts (stannous salts, stannic salts), alkali stannates such as potassium stannate and sodium stannate, and these may be used alone or in admixture of two or more. Of these, it is industrially desirable to use an aqueous hydrochloric acid solution of tin chloride.
[0007]
The antimony compound, antimony halides such as antimony chloride, Or, including inorganic salts such as sulfates of antimony and the like, may be mixed singly or two or more. In particular, it is industrially desirable to use an aqueous hydrochloric acid solution of antimony chloride.
The amount of antimony oxide added is 1 to 30% by weight, preferably 5 to 20% by weight, based on tin oxide.
[0008]
As the silicon compound, in addition to silicon chloride, soluble silicates such as potassium silicate and sodium silicate can be used. When using silicon chloride, it is desirable to use it as a solution in which 0.1 to 100 g / l silicon chloride is dissolved in one or more solutions or mixed solutions of alcohol, aqueous hydrochloric acid and acetone. In the case of soluble silicates, those aqueous solutions are preferably used. Silica sol can be used instead of silicon chloride. Furthermore, various silane coupling agents, silicone oil, colloidal silica, and the like can be used.
When silicon chloride is used as the silicon compound, it can be added as a single solution with or without mixing with each solution of tin chloride or antimony chloride. When a soluble silicate is used as the silicon compound, it can be added as a single solution or as a solution dissolved in an alkaline solution.
The amount of silicon oxide added is 6% by weight or less, desirably 4% by weight or less, based on tin oxide.
[0009]
In the method of the present invention, first, a tin chloride solution is neutralized with an alkali to form a tin oxide hydrate. The antimony chloride solution is then neutralized with alkali to produce antimony oxide hydrate.
[0010]
Further, the neutralization reaction of each solution of tin chloride and antimony chloride is, for example, (a) neutralizing each solution of tin chloride or antimony chloride and an aqueous alkaline solution in parallel in hot water, (b ) Add an aqueous alkaline solution to each solution of tin chloride or antimony chloride to neutralize, (c) Add an aqueous solution of tin chloride or antimony chloride to neutralize the solution. . Among these methods, the method (a) is particularly desirable industrially. In this case, the pH of the neutralization reaction solution is preferably maintained at 3 or more, preferably 5 to 10.
[0011]
Further, when the silicon compound is present in at least one of the step of forming a tin oxide hydrate and the step of forming an antimony oxide hydrate, for example, (1) a tin oxide hydrate and Add to form a coprecipitate with hydrate of silicon oxide, or (2) Add to form hydrate of silicon oxide on it after forming hydrate of tin oxide And (3) added to form a coprecipitate of antimony oxide hydrate and silicon oxide hydrate, or (4) after forming antimony oxide hydrate, To form a hydrate of silicon oxide.
[0012]
In the method of the present invention, it is desirable to carry out the neutralization reaction under heating or in hot water, but it can also be carried out at room temperature without heating.
Examples of the alkaline aqueous solution used as the neutralizing agent include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, carbonates and ammonia, and acidic aqueous solutions include hydrochloric acid and sulfuric acid. These may be used alone or in combination of two or more.
[0013]
In the method of the present invention, next, the product is filtered from the reaction solution after completion of the neutralization reaction, and washed and recovered as necessary. In this case, it is desirable to add an acid to the reaction solution after completion of the neutralization reaction to adjust the pH of the reaction solution to 5 or less, preferably 2 to 4, and then filter the product. When an alkali metal hydroxide or carbonate is used as a neutralizing agent, the alkali metal is adsorbed to the product due to insufficient washing, and if left, the alkali metal is transferred into the SnO 2 crystal of Sb in the baking step described later. Therefore, when Sb is dissolved in the SnO 2 crystal, it is necessary to perform sufficient washing so that no alkali metal remains. In addition, it is desirable that the salt generated by neutralization in the step of producing a tin oxide hydrate is removed by washing and then subjected to a step of producing an antimony oxide hydrate.
[0014]
The recovered product is then dried if necessary and then calcined at a temperature of 400 to 800 ° C., preferably 500 to 700 ° C. In the method of the present invention, when silicon oxide (hydrous material) is contained in the precipitate, the silicon compound suppresses sintering of the particles during firing, and finer particles can be obtained. The firing time is suitably from 30 minutes to 5 hours. After firing, it is dried and pulverized according to a conventional method to obtain a conductive fine powder.
[0015]
The conductive antimony-containing tin oxide fine powder of the present invention is blended as a conductivity-imparting material or substrate in plastics, rubber, fiber, etc., conductive resin composition, conductive paint composition, magnetic paint, conductive rubber, It can utilize as electroconductive compositions, such as electroconductive fiber.
[0016]
When used as a conductive resin composition, various types of so-called general-purpose plastics and engineering plastics can be used. Examples of general-purpose plastics include polyethylene, vinyl chloride resin, polystyrene, polypropylene, methacrylic resin, The urea melamine resin is an engineering plastic general-purpose plastic, for example, a phenol resin, an unsaturated polyester resin, a hard vinyl chloride resin, an ABS resin, and an AS resin, and the engineering plastic is, for example, an epoxy resin, polyacetal, polycarbonate, poly Butylene terephthalate, polyethylene terephthalate, polyphenylene ether, polyphenylene sulfide, polysulfone, fluororesin, super engineering Examples of the plastic include diallyl phthalate resin, silicon resin, polyimide resin, polyamide imide, bismaleimide triazine, polyamino bismaleimide, olefin vinyl alcohol copolymer, polyoxybenzylene, polymethylpentene, polyethersulfone, polyetherimide. , Polyarylate, polyetheretherketone and the like, and are blended in these resins. The blending amount of the conductive antimony-containing tin oxide fine powder in the molding resin is 3 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the resin.
[0017]
When the conductive antimony-containing tin oxide fine powder of the present invention is used as a conductive coating composition or a magnetic coating composition, various binders such as polyvinyl alcohol resin, PVC-vinyl acetate resin, acrylic resin, epoxy resin, Urethane resin, alkyd resin, polyester resin, ethylene vinyl acetate copolymer, acrylic-styrene copolymer, fiber resin, phenol resin, amino resin, fluorine resin, silicone resin, petroleum resin, shellac, rosin derivative, rubber derivative, etc. And is dispersed in water or a solvent. The blending amount of the conductive antimony-containing tin oxide fine powder in the binder resin is 3 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the binder solid content. In the case of a conductive coating composition, the coating is applied to an insulating substrate such as paper or a polymer film, so that the conductive material is light and transparent on the substrate and has excellent surface smoothness and adhesion. Various antistatic coatings, electrostatic recording paper, electrophotographic copying paper, and the like can be formed by forming a conductive coating.
[0018]
When the conductive antimony-containing tin oxide fine powder obtained by the method of the present invention is applied to an aqueous paint, the fine powder of the tin oxide is wet pulverized to prepare an aqueous dispersion. In the case of use in the process, it is extremely preferable to reduce the dispersion energy at the time of coating. The aqueous dispersion has a solid content concentration of 1 to 70% by weight, preferably 10 to 50% by weight, and a pH of 4 to 12, preferably 5 to 10.
[0019]
The conductive composition thus obtained has excellent conductivity and transparency as compared with the conductive composition containing the antimony-containing tin oxide fine powder obtained by the conventional method. It has a small (reduced) blue tint.
[0020]
【Example】
Example 1
A solution prepared by dissolving 500 g of stannic chloride pentahydrate in 500 ml of 3N hydrochloric acid solution in 5 l of pure water at 90 ° C. and a sodium hydroxide solution are maintained so that the pH of the system is 7 to 7.5. Parallel addition over 20 minutes produced a precipitate of tin oxide hydrate. Next, hydrochloric acid was added thereto to adjust the pH of the system to 3, and then the precipitate was filtered, and then washed with water until the specific resistance of the filtrate reached 20000 Ωcm. The obtained cake was repulped into 5 liters of pure water, heated to 90 ° C., and a solution obtained by dissolving 37.0 g of antimony trichloride in 300 ml of 3N hydrochloric acid aqueous solution and sodium hydroxide solution was adjusted to a pH of 7 to Antimony oxide hydrate was deposited on the tin oxide hydrate by parallel addition over 20 minutes to maintain 7.5. Thereafter, hydrochloric acid was added to adjust the pH of the system to 3, filtered, and then washed with water until the specific resistance of the filtrate reached 20000 Ωcm. The obtained cake was baked in an electric furnace at 600 ° C. for 4 hours and pulverized with a pulverizer to obtain a conductive fine powder having a specific surface area of 46.0 m 2 / g and a powder resistance of 4.6 Ωcm. The b value of the powder color (press pressure 200 kg / cm 2 ) was −5.8, and the L value was 53.4.
[0021]
Comparative Example 1
A solution prepared by dissolving 500 g of stannic chloride pentahydrate and 37.0 g of antimony trichloride in 500 ml of 3N hydrochloric acid solution and 200 g / l sodium hydroxide solution in 5 l of pure water at 90 ° C. was added to the pH of the system. Was added in parallel over 20 minutes to maintain 7 to 7.5 to produce a coprecipitate of tin oxide and antimony oxide hydrate. Next, hydrochloric acid was added thereto to adjust the pH of the system to 3, and then the precipitate was filtered, and then washed with water until the specific resistance of the filtrate reached 20000 Ωcm. The obtained cake was baked in an electric furnace at 600 ° C. for 4 hours and pulverized by a pulverizer to obtain a conductive fine powder having a specific surface area of 46.1 m 2 / g and a powder resistance of 2.0 Ωcm. The b value of the powder color (pressing pressure 200 kg / cm 2 ) was −12.0, and the L value was 24.0.
[0022]
Example 2
A solution of 500 g of stannic chloride pentahydrate in 500 ml of 3N hydrochloric acid solution, 17.4 ml of sodium silicate aqueous solution (308 g as SiO 2 ) and sodium hydroxide aqueous solution in 5 l of pure water at 90 ° C. Co-precipitates were formed by parallel addition over 20 minutes to maintain the pH of the system at 7-7.5. Next, hydrochloric acid was added thereto to adjust the pH of the system to 3, and then the coprecipitate was filtered, and then washed with water until the specific resistance of the filtrate reached 20000 Ωcm. The obtained cake was repulped into 5 liters of pure water, heated to 90 ° C., and a solution obtained by dissolving 37.0 g of antimony trichloride in 300 ml of 3N hydrochloric acid aqueous solution and sodium hydroxide solution was adjusted to a pH of 7 to Antimony oxide hydrate was deposited on the coprecipitate of tin oxide and silicon oxide hydrate by parallel addition over 20 minutes to maintain 7.5. Thereafter, hydrochloric acid was added to adjust the pH of the system to 3, filtered, and washed with water until the specific resistance of the filtrate reached 20000 Ωcm. The obtained cake was baked in an electric furnace at 600 ° C. for 4 hours and pulverized by a pulverizer to obtain a conductive fine powder having a specific surface area of 77.5 m 2 / g and a powder resistance of 2.6 Ωcm. The powder color (pressing pressure 200 kg / cm 2 ) had a b value of −7.8 and an L value of 41.0.
[0023]
Comparative Example 2
In 5 liters of 90 ° C. pure water, 500 g of stannic chloride pentahydrate and 37.0 g of antimony trichloride are dissolved in 500 ml of 3N hydrochloric acid aqueous solution, and 17.4 ml of sodium silicate aqueous solution (308 g as SiO 2 ) Sodium hydroxide solution was added in parallel over 20 minutes to maintain the pH of the system at 7-7.5 to produce a coprecipitate of tin oxide, antimony oxide and silicon oxide. Next, hydrochloric acid was added thereto to adjust the pH of the system to 3, and the coprecipitate was filtered, and then washed with water until the specific resistance of the filtrate reached 20000 Ωcm. The obtained cake was baked in an electric furnace at 600 ° C. for 4 hours and pulverized with a pulverizer to obtain a conductive fine powder having a specific surface area of 75.0 m 2 / g and a powder resistance of 1.9 Ωcm. The b value of the powder color (pressing pressure 200 Kg / cm 2 ) was −13.0, and the L value was 32.0.
[0024]
Test Example 1 (Evaluation of powder resistance)
The sample powder was molded at a pressure of 100 kg / cm 2 to form a cylindrical green compact (diameter 18 mm, thickness 3 mm), its direct current resistance was measured, and the powder resistance (Ωcm) was determined from the following equation.
Powder resistance = measured value x 2.54 (electrode constant) / thickness (cm)
Samples 0.1 to 0.2 g were collected and degassed in nitrogen gas at 150 ° C. for 30 minutes. Thereafter, the specific surface area was measured by the BET method in a nitrogen / helium mixed gas system using a specific surface area measuring apparatus (Flowsorb 2300, manufactured by Micromeritic).
[0025]
Test Example 2 (Measurement of powder color)
The sample powder is molded at a pressure of 200 kg / cm 2 to form a cylindrical green compact (diameter 33 mm, thickness 5 mm), and a powder color (color computer, SM-7-IS-2B type, manufactured by Suga Test Instruments) is used. It was measured.
[0026]
Test example 3
20 g each of the conductive fine powders of the samples obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were added to an acrylic resin (Acridic A-165-45, solid content 45% by weight, manufactured by Dainippon Ink & Chemicals, Inc.). 30.6 g, 26.4 g of toluene-butanol mixed solution (mixing weight ratio 1: 1) and 50 g of glass beads, and then mixed in a paint shaker (Red Devil, # 5110) and shaken for 20 minutes. Each mill base was prepared.
Next, a predetermined amount of each of the acrylic resin and the toluene-butanol mixed solution was added to each mill base, and the mixture was stirred and mixed to prepare each pigment concentration (wt%) paint shown in Table 1. This paint was applied to a polyester film and white chart paper so as to have a dry film thickness of 4 μm and naturally dried for 40 hours to prepare a test sheet. The surface resistivity (Ω / □) of the polyester film sheet was measured (digital ohm meter: R-506 type, manufactured by Kawaguchi Electric Co., Ltd.), and the color (color computer, SM-7-IS-2B) was measured for the white chart paper sheet. Mold, manufactured by Suga Test Instruments).
Further, the haze degree (%) was measured (haze meter: NDH-300A type, manufactured by Nippon Denshoku Industries Co., Ltd.). These results are shown in Tables 1 and 2.
[0027]
[Table 1]
[Table 2]
【The invention's effect】
As is apparent from Tables 1 and 2, according to the present invention, conductive antimony-containing tin oxide fine powder having excellent transparency and conductivity and a small bluish color tone can be produced industrially advantageously. it can.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14569995A JP3647929B2 (en) | 1995-05-18 | 1995-05-18 | Method for producing conductive antimony-containing tin oxide fine powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14569995A JP3647929B2 (en) | 1995-05-18 | 1995-05-18 | Method for producing conductive antimony-containing tin oxide fine powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08319118A JPH08319118A (en) | 1996-12-03 |
| JP3647929B2 true JP3647929B2 (en) | 2005-05-18 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14569995A Expired - Fee Related JP3647929B2 (en) | 1995-05-18 | 1995-05-18 | Method for producing conductive antimony-containing tin oxide fine powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3647929B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI300382B (en) | 2001-03-30 | 2008-09-01 | Jsr Corp | |
| JP4182825B2 (en) | 2002-07-01 | 2008-11-19 | 住友金属鉱山株式会社 | Antimony tin oxide fine particles for sunscreen, dispersion for forming sunscreen using the same, sunscreen and transparent substrate for sunscreen |
| JP5301370B2 (en) * | 2008-07-02 | 2013-09-25 | 石原産業株式会社 | Tin oxide particles and method for producing the same |
| JP2015228352A (en) * | 2014-06-02 | 2015-12-17 | 三井金属鉱業株式会社 | Conductive particle |
| JP6559509B2 (en) * | 2015-09-08 | 2019-08-14 | 三菱マテリアル電子化成株式会社 | Antimony-doped tin oxide conductive film forming composition and antimony-doped tin oxide conductive film |
-
1995
- 1995-05-18 JP JP14569995A patent/JP3647929B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08319118A (en) | 1996-12-03 |
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