JP3609159B2 - Acicular conductive antimony-containing tin oxide fine powder and method for producing the same - Google Patents
Acicular conductive antimony-containing tin oxide fine powder and method for producing the same Download PDFInfo
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Description
【0001】
【産業上の利用分野】
本発明は、針状導電性アンチモン含有酸化錫微粉末およびその製造方法であって、種々の用途分野において適用性の拡大及び高付加価値化の増大を図り得る優れた高機能性材料に関する。
【0002】
【従来の技術】
プラスチックス、ゴム、繊維などの導電性付与剤或いは帯電防止剤として、更には電子写真複写紙、静電記録紙などの記録材料の支持体用導電性付与剤としては、種々のものが提案されている。例えばアンチモン含有酸化錫球状粉末(例えば、特開平4−77317 号)、導電性酸化第二錫繊維(例えば、特開昭61−17421号)、二酸化チタン粉末の表面に酸化錫或いは酸化錫と酸化アンチモンから成る導電層を被覆した導電性粉末(例えば、特開昭56−41603号)、表面が酸化第二錫で覆われた繊維状チタン酸カリウム(例えば、特公昭61−26933号)などが知られている。
【0003】
【発明が解決しようとする課題】
ところで、前記した酸化錫系や二酸化チタン系、さらにはチタン酸カリウム系の導電性粉末は、いわゆる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、近年例えば、塗料、インク、プラスチックス、繊維など種々の分野での素材や製品の帯電防止用導電性付与剤として、さらには補強性フィラーとして、その機能性材料としての利用が注目され、急速に適用が図られつつある。
【0004】
しかして、通常、これらの導電性付与剤は、ゴム、プラスチックス、紙等に充填するか、或いは結合剤を含む溶液中に分散して塗布液とし、これを種々のフィルム、シート、支持体、さらには筐体などの被処理体上に塗布するかして用いられるが、良好な導電性を得るには、少なくとも隣接する粉末同志が密に接触するように粉体の含有量を多くしなければならない。従って、このような粉末を用いて透明性が要求される導電性材料或いは導電層を作成しようとすることは困難である。
【0005】
針状或いは繊維状の導電性付与剤を用いれば、単位面積当たり或いは単位容積当たり、少量の導電性付与剤でも導電路を有効に形成することが可能であるが、例えばカーボンファイバー、金属ウール、金属ウイスカー等を用いれば、これらはいずれも着色しているので、透明性が要求される場合或いは紙等の白色度が要求される場合には不適当である。
【0006】
このような問題を解決するために、例えば繊維状チタン酸カリウムの表面に酸化錫の導電層を被覆した白色導電性物質が提案されている。このものは粒子形状の点では問題ないものの、粉体抵抗値が高く、かつ強度の点でも満足できないものであり、導電層を酸化錫と酸化アンチモンの組成に変えても含まれるカリウム成分の影響で粉体抵抗値の低いものが得られ難いという問題がある。
【0007】
また、従来の導電性酸化第二錫繊維は、例えば直径0.5μm、長さ約3mmという太くて長いものであり、特に透明性を要求される分野には使用できず、その製造方法も、電気炉で原料を溶融し、繊維状物を析出させる方法であって、長時間を要し、工業的でない。
【0008】
しかして、前記のような導電性粉末の用途適用において、近時、例えばOHPフィルムやCRT窓、さらにはICパッケージや電子機器の筐体などの静電気障害回避のための帯電防止処理、液晶ディスプレイやその他EL体の透明電極などのように、所望の導電性付与能を奏するとともに、被処理体の生地表面に対して実質的に光吸収を伴うことなく、かつ超薄膜の導電性膜を形成し得ることが求められている。
【0009】
本発明者等は、先に錫成分、アンチモン成分及びケイ素成分を含む含水酸化錫を、アルカリ金属のハロゲン化物又はホウ素化合物の存在下で焼成することによって、針状性の極めて優れた導電性アンチモン含有酸化錫微粉末を提案している。このものは前記従来技術の問題点を解消し、種々の用途適用分野の被処理体に対して好適な導電性及び透明性を付与する上で優れたものである。
しかしながら、前記導電性アンチモン含有酸化錫微粉末の粉体色は、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など、適用媒体系における導電性、透明性、色調の三つの特性を、ともに十分満足し得るさらなる改善が希求されている。
【0010】
【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針状導電性酸化錫微粉末において、前記課題の導電性、透明性の付与性能を損なわずに青味色調化の低減を図るべく、更に検討を進めた結果、意外にも、針状酸化錫微粉末の粒子表面に含水酸化アンチモンを生成させた後分別回収し、このものを焼成することによって、青味分が非常に少なく、しかも明度が高く、導電性、透明性がともに優れ、かつ針状性の良好な導電性アンチモン含有酸化錫微粉末となり得ることの知見を得、本発明を完成した。
【0011】
すなわち、本発明は、短軸平均粒子径が0.005〜1μmであり、長軸平均粒子径が0.05〜10μmであって、アスペクト比が3以上である針状酸化錫粒子の懸濁液に、アンチモン化合物溶液とアルカリ水溶液とを並行的に添加し中和して、Sb/Snの原子比として0.1/100〜20/100の量の含水酸化アンチモンを該酸化錫粒子表面に沈着させ、しかる後分別回収物を700〜1000℃で焼成する、該粒子粉体の粉末抵抗が1kΩcm以下で、かつ粉体色のL値が80〜90である針状導電性アンチモン含有酸化錫微粉末の製造方法である。
【0012】
なお、本発明において「針状」とは、その物性値の範囲における針状のものの他、繊維状、柱状、棒状、その他類似形状のものも包含する。
【0013】
本発明の針状導電性アンチモン含有酸化錫微粉末は、基体粒子としての針状酸化錫粒子の表面に含水酸化アンチモンを沈着した後、焼成することにより得ることができる。用いる前記基体粒子の針状酸化錫粉末は、種々の方法で作成出来るが、例えば、SnO2/SiO2/NaCl混合物を焼成する方法(特願平7−31506 )、SnO2/ホウ砂混合物を焼成する方法(特願平7−56496 )、針状の蓚酸錫を加熱分解する方法(特開昭56−120519 )、錫と銅の混合物を溶融し、冷却する方法(特開昭62−158199 )等が挙げられる。含水酸化アンチモンの針状酸化錫上への沈着は、例えばこれらの針状酸化錫を水、アルコール等の溶媒中に分散して懸濁液とし、ここへ攪拌下アンチモン化合物の水溶液或いはアルコール溶液を添加、中和することで行なうことができる。前記基体粒子は、短軸平均粒子径が0.005〜1μm、好ましくは0.005〜0.2μmであり、長軸平均粒子径が0.05〜10μm、好ましくは0.1〜3μmであって、アスペクト比が3以上であるものが望ましい。
【0014】
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。アンチモン化合物の溶液を中和して針状酸化錫粒子上に含水酸化アンチモンを沈着させるには、種々の方法によって行ない得るが、例えば(a)アンチモン化合物水溶液とアルカリ水溶液とを酸化錫分散スラリーに並行的に添加して中和する、(b)アンチモン化合物水溶液を酸化錫分散スラリーに添加し、その後アルカリ水溶液を添加し中和する、(c)アンチモン化合物水溶液を酸化錫分散スラリーに添加し、その後沸点まで昇温し、加熱加水分解させる、などの方法が挙げられる。上記(a)〜(b)において、酸化錫分散スラリーは室温下でもよいが、加熱下例えば70〜90℃で行なった場合は、より均一な含水酸化アンチモンの沈着が得られ易く、好ましい。
【0015】
なお、前記のアンチモン化合物溶液の中和に使用されるアルカリ水溶液のアルカリとしては、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。
【0016】
次に、前記含水酸化アンチモン沈着処理生成物を濾別し洗浄して回収するが、中和剤として使用したアルカリ金属成分を十分洗浄、除去することによって、後記焼成工程におけるアンチモン成分の作用による導電性の発現を一層好ましいものとすることができる。前記の回収生成物は、必要に応じ、乾燥、粉砕等の処理を施した後、焼成する。焼成は、700〜1000℃で行なうことができ、焼成温度が700℃より低きに過ぎると導電性が不十分となり、また、1000℃を超えると、短軸の太いものとなり、元の形状が維持出来なくなる。焼成時間は30分〜5時間が適当である。
【0017】
針状酸化錫への含水酸化アンチモンの沈着割合は、針状アンチモン含有酸化錫微粉末のアンチモン成分量が、Sb/Snの原子比として0.1/100〜20/100、好ましくは、1/100〜15/100となるようにするのが良く、Sb/Sn<0.1/100では、所望の導電性が得られず、また、Sb/Sn>20/100では、十分な導電性を示す針状微粉末が得られない。
【0018】
本発明の針状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、導電性プラスチックス、導電性塗料、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。導電性プラスチックス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。針状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。
【0019】
本発明の針状導電性アンチモン含有酸化錫微粉末を、導電性塗料或いは磁性塗料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。針状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。なお、本発明の針状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、該酸化錫微粉末もしくは該酸化錫微粉末の製造工程から得られる可溶性塩類を除去処理した後の処理ケーキを、水性媒体に分散させて成る水性分散体を調製し、該水性分散体を塗料化に供する場合は、塗料化時の分散エネルギーや該酸化錫微粉末製造工程における脱水、乾燥エネルギーの軽減を図る上で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。
【0020】
一方、磁気記録媒体の製造に使用される塗料の場合には、非磁性支持体と磁性層等の接着力の向上、磁気記録媒体の帯電防止、膜強度の強化、磁性層の薄層化、表面平滑化に伴う下層非磁性層の分散性、表面平滑性向上に有用である。とりわけ、近年磁気記録の高記録密度化とともに記録波長が短くなる傾向が著しく、これとあいまって磁気記録媒体の磁性層の薄層化が一層要請されている。しかしながら、磁性層の薄層化は、磁性表面に支持体の影響が現れ易く、電磁変換特性の悪化が避けられない。このために、例えば非磁性支持体表面に非磁性の下塗層を設けてから磁性層を上層として設けることによって支持体の表面粗さによる影響を解消するとともに、磁性層を薄層化して高出力化を図る方法が行なわれている。本発明の針状導電性アンチモン含有酸化錫微粉末の前記下層非磁性層への充填割合は、体積充填率で20〜80%程度である。
【0021】
導電性ゴムとして利用する場合には、例えばシリコーンゴム、イソプレンゴム、スチレン−ブタジエンゴム、ブタジエンゴム、ブチルゴム、ブタジエン−アクリロニトリルゴム、エチレン−プロピレン−ジエタンポリマー、エチレン−プロピレンゴム、フッ素ゴム、エチレン−酢酸ビニル共重合体、塩素化ポリエチレン、アクリルゴム、クロロプレンゴム、ウレタンゴム、多硫化ゴム、クロロスルホン化ポリエチレンゴム、エピクロルヒドリンゴムなど従来から知られているものに配合される。
【0022】
導電性繊維として利用する場合には、例えばポリアミド樹脂、ポリエステル樹脂、ポリオレフィン樹脂、ポリビニル樹脂、ポリエーテル樹脂などの可錘性の繊維に配合される。
【0023】
このようにして得られた導電性組成物は、従来の球状や針状の導電性粉末を配合した導電性組成物に比べて、樹脂バインダーに対してより少ない配合量で高い導電性が得られると共に、透明性も優れており、経済的にも有利である。このように少ない配合量でよいことから、バインダーの強度低下を起こすことなく利用することができる。また高濃度の導電性塗料としたときは、薄い塗膜にしても所望の導電性が得られる。とりわけ、優れた導電性、透明性の特性と共に、従来にない青味色調の低減されたものとなり得る。
【0024】
【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、ケイ酸ナトリウム水溶液(SiO2として308g/l)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110℃で12時間乾燥した後、この乾燥状物100重量部に対して、20重量部の割合の塩化ナトリウムを加え、両者を均一に混合粉砕した。この混合物を電気炉で900℃にて1時間焼成した。しかる後、得られた焼成生成物をフッ化水素酸水溶液で浸漬処理して可溶性塩類を除去した後、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3.36g(Sb/Sn原子比:1/100)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、針状酸化錫上に含水酸化アンチモンを沈着させた。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900℃にて1時間焼成し、パルベライザーで粉砕して、本発明の針状導電性アンチモン含有酸化錫微粉末を得た。このものの短軸平均粒子径は0.015μm、長軸平均粒子径は0.50μm、アスペクト比33で、粉体抵抗は18.5Ωcmであり、また、粉体色(プレス圧力200Kg/cm2 )のb値は−5.8、L値は82.3であった。
【0025】
実施例2
前記実施例1において、含水酸化アンチモン沈殿後の分別回収ケーキの焼成温度を1000℃としたこと以外は、同例の場合と同様に処理して本発明の針状導電性アンチモン含有酸化錫微粉末を得た。このものの短軸平均粒子径は0.024μm、長軸平均粒子径は0.52μm、アスペクト比22で、粉体抵抗は31.7Ωcmであり、また、粉体色(プレス圧力200Kg/cm2 )のb値は−4.6、L値は85.9であった。
【0026】
実施例3
前記実施例1において、三塩化アンチモンの使用量を16.82g(Sb/Sn原子比:5/100)としたこと以外は、同例の場合と同様に処理して本発明の針状導電性アンチモン含有酸化錫微粉末を得た。このものの短軸平均粒子径は0.014μm、長軸平均粒子径は0.50μm、アスペクト比36で、粉体抵抗は8.0Ωcmであり、また、粉体色(プレス圧力200Kg/cm2 )のb値は−6.0、L値は81.0であった。
【0027】
比較例
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3.36g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/l)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15000Ωcmになるまで水洗した。得られたケーキを110℃で12時間乾燥した後、この乾燥状物100重量部に対して、20重量部の割合の塩化ナトリウムを加え、両者を均一に混合粉砕した。この混合物を電気炉で900℃にて1時間焼成した。しかる後、得られた焼成生成物をフッ化水素酸水溶液で浸漬処理して可溶性塩類を除去した後、乾燥、粉砕を行って、針状導電性アンチモン含有酸化錫微粉末を得た。このものの短軸平均粒子径は0.011μm、長軸平均粒子径は0.50μm、アスペクト比45で、粉体抵抗は32.5Ωcmであり、また、粉体色(プレス圧力200Kg/cm2 )のb値は−9.4、L値は73.6であった。
【0028】
なお、前記各実施例及び比較例における各粒子径、粉体抵抗及び粉体色は、次の各方法によって測定した。
(1)電子顕微鏡写真(倍率10万倍)を観察して重量平均粒子径を求め、またそれに基づいてアスペクト比を算出した。
(2)各試料粉末の100Kg/cm2 の圧力下での比抵抗(Ωcm)を測定した(デジタルマルチメータ:Model 2502A 、横河北辰電機会社製)。
(3) 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(カラーコンピューター、SM−7−IS−2B型、スガ試験機製)を測定した。
【0029】
【発明の効果】
本発明は、とりわけ青味色調が小さくまた明度が高く、かつ透明性、導電性に優れた針状導電性アンチモン含有酸化錫微粉末、及びその工業的有利な製造方法を提供することができる。[0001]
[Industrial application fields]
The present invention relates to an acicular conductive antimony-containing tin oxide fine powder and a method for producing the same, and relates to an excellent high-functional material capable of expanding applicability and increasing added value in various fields of use.
[0002]
[Prior art]
Various electroconductivity imparting agents such as plastics, rubber and fibers, or antistatic agents, and various electroconductivity imparting agents for recording materials such as electrophotographic copying paper and electrostatic recording paper have been proposed. ing. For example, antimony-containing tin oxide spherical powder (for example, Japanese Patent Laid-Open No. 4-77317), conductive stannic oxide fiber (for example, Japanese Patent Laid-Open No. 61-17421), and titanium dioxide powder are oxidized with tin oxide or tin oxide. Conductive powder (for example, JP-A-56-41603) coated with a conductive layer made of antimony, fibrous potassium titanate whose surface is covered with stannic oxide (for example, JP-B 61-26933), etc. Are known.
[0003]
[Problems to be solved by the invention]
By the way, the above-described tin oxide-based, titanium dioxide-based, and potassium titanate-based conductive powders exhibit a so-called electron-conducting conductive function compared to so-called ion-conducting types such as polymer electrolytes, High stability of conductivity against humidity and temperature. In recent years, for example, as an antistatic conductivity imparting agent for materials and products in various fields such as paints, inks, plastics and fibers, and further as a reinforcing filler. Its use as a functional material has attracted attention and is being applied rapidly.
[0004]
Usually, these conductivity-imparting agents are filled in rubber, plastics, paper or the like, or dispersed in a solution containing a binder to form a coating solution, which is used as various films, sheets, and supports. In order to obtain good conductivity, the powder content should be increased so that at least adjacent powders are in close contact with each other. There must be. Therefore, it is difficult to create a conductive material or a conductive layer that requires transparency using such a powder.
[0005]
If a needle-like or fibrous conductivity-imparting agent is used, a conductive path can be effectively formed even with a small amount of conductivity-imparting agent per unit area or unit volume. For example, carbon fiber, metal wool, If metal whiskers or the like are used, they are all colored, and thus are not suitable when transparency is required or when whiteness such as paper is required.
[0006]
In order to solve such a problem, for example, a white conductive material in which a surface of fibrous potassium titanate is coated with a conductive layer of tin oxide has been proposed. Although there is no problem in terms of particle shape, this powder is high in powder resistance and unsatisfactory in terms of strength, and even if the conductive layer is changed to a composition of tin oxide and antimony oxide, the effect of the potassium component contained However, it is difficult to obtain a powder having a low powder resistance value.
[0007]
Further, the conventional conductive stannic oxide fiber is, for example, thick and long with a diameter of 0.5 μm and a length of about 3 mm, and cannot be used particularly in fields that require transparency. This is a method of melting raw materials in a furnace and precipitating fibrous materials, which takes a long time and is not industrial.
[0008]
Thus, in the application of the conductive powder as described above, recently, for example, an OHP film, a CRT window, an antistatic treatment for avoiding static electricity troubles such as an IC package or a housing of an electronic device, a liquid crystal display, Other than the EL electrode transparent electrode, etc., it provides the desired conductivity imparting ability, and forms an ultra-thin conductive film without substantial light absorption on the surface of the cloth of the object to be processed. There is a need to get.
[0009]
The present inventors previously conducted conductive antimony with extremely excellent acicularity by firing a hydrous tin oxide containing a tin component, an antimony component and a silicon component in the presence of an alkali metal halide or boron compound. Proposed tin oxide fine powder. This is superior in solving the problems of the prior art and imparting suitable conductivity and transparency to the object to be treated in various application fields.
However, the powder color of the electroconductive antimony-containing tin oxide fine powder tends to be a bluish-black color tone, and therefore it is easy to cause a bluish color tone and darkening in the various application systems using this. There is a need for further improvements that can sufficiently satisfy the three characteristics of the material, conductivity, transparency, and color tone.
[0010]
[Means for Solving the Problems]
The present inventors have further studied to reduce the blue tint without impairing the conductivity and transparency imparting performance of the above-mentioned problems in the needle-shaped conductive tin oxide fine powder containing antimony. As a result, surprisingly, by generating and collecting hydrous hydrated antimony on the surface of the fine particles of acicular tin oxide fine powder, and firing this, it has a very low bluish content, high brightness, and conductivity. The present invention has been completed by obtaining the knowledge that the conductive antimony-containing tin oxide fine powder is excellent in both properties and transparency and has good acicularity.
[0011]
That is, the present invention is the minor axis average particle diameter of 0.005 to 1 [mu] m, a major axis average particle diameter of 0.05 to 10 [mu] m, suspended in acicular tin oxide particles child is an aspect ratio of 3 or more An antimony compound solution and an aqueous alkali solution are added to the turbid solution in parallel to neutralize it , so that hydrous antimony in an amount of 0.1 / 100 to 20/100 as the atomic ratio of Sb / Sn is added to the surface of the tin oxide particles. is deposited on, whereafter separate collection was calcined at 700 to 1000 ° C., the powder resistance of the particles powder below 1 k? cm, and acicular conductive antimony-containing oxide L value of the powder color is 80 to 90 is a manufacturing how at the end of tin fines.
[0012]
In the present invention, the term “needle” includes not only needles in the range of physical properties but also fibers, columns, rods, and other similar shapes.
[0013]
The acicular conductive antimony-containing tin oxide fine powder of the present invention can be obtained by depositing hydrous antimony oxide on the surface of acicular tin oxide particles as base particles and then firing. The acicular tin oxide powder of the base particles to be used can be prepared by various methods. For example, a method of baking a SnO 2 / SiO 2 / NaCl mixture (Japanese Patent Application No. 7-31506), a SnO 2 / borax mixture A method of firing (Japanese Patent Application No. 7-56496), a method of thermally decomposing acicular tin oxalate (Japanese Patent Laid-Open No. 56-120519), a method of melting a mixture of tin and copper and cooling (Japanese Patent Laid-Open No. 62-158199) ) And the like. The deposition of hydrous antimony on acicular tin oxide is carried out, for example, by dispersing these acicular tin oxides in a solvent such as water or alcohol to form a suspension. It can be performed by adding and neutralizing. The base particles have a minor axis average particle diameter of 0.005 to 1 μm, preferably 0.005 to 0.2 μm, and a major axis average particle diameter of 0.05 to 10 μm, preferably 0.1 to 3 μm. The aspect ratio is preferably 3 or more.
[0014]
Examples of the antimony compound include antimony halides such as antimony chloride or inorganic acid salts such as antimony sulfate, and these may be used alone or in combination of two or more. In particular, it is industrially desirable to use an aqueous hydrochloric acid solution of antimony chloride. Various methods can be used to neutralize the antimony compound solution and deposit the hydrous antimony on the acicular tin oxide particles. For example, (a) an antimony compound aqueous solution and an alkaline aqueous solution are mixed into a tin oxide dispersed slurry. (B) An antimony compound aqueous solution is added to the tin oxide dispersed slurry, and then neutralized by adding an alkaline aqueous solution. (C) An antimony compound aqueous solution is added to the tin oxide dispersed slurry, Thereafter, the temperature is raised to the boiling point, followed by heat hydrolysis. In the above (a) to (b), the tin oxide-dispersed slurry may be at room temperature. However, when carried out under heating, for example, at 70 to 90 ° C., more uniform deposition of hydrous antimony oxide is preferred, which is preferable.
[0015]
Examples of the alkali of the alkaline aqueous solution used for neutralization of the antimony compound solution include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, carbonates and ammonia. These may be used alone or in admixture of two or more.
[0016]
Next, the hydrous antimony-containing antimony deposition treatment product is separated by filtration, washed and recovered. By sufficiently washing and removing the alkali metal component used as a neutralizing agent, the conductivity due to the action of the antimony component in the post-baking step is obtained. The expression of sex can be made even more preferable. The recovered product is baked after being subjected to a treatment such as drying and pulverization, if necessary. Firing can be performed at 700 to 1000 ° C. If the firing temperature is too low, the conductivity becomes insufficient. If the firing temperature exceeds 1000 ° C, the short axis becomes thick and the original shape is reduced. It cannot be maintained. The firing time is suitably from 30 minutes to 5 hours.
[0017]
The deposition ratio of hydrous antimony oxide to acicular tin oxide is such that the antimony component amount of acicular antimony-containing tin oxide fine powder is 0.1 / 100 to 20/100 as the atomic ratio of Sb / Sn, preferably 1 / It is preferable to satisfy 100 to 15/100. When Sb / Sn <0.1 / 100, desired conductivity cannot be obtained, and when Sb / Sn> 20/100, sufficient conductivity is obtained. The needle-shaped fine powder shown cannot be obtained.
[0018]
The acicular conductive antimony-containing tin oxide fine powder of the present invention is blended in plastics, rubber, fiber, etc. as a conductivity-imparting material or substrate, and conductive plastics, conductive paint, magnetic paint, conductive rubber, conductive It can utilize as electroconductive compositions, such as a conductive fiber. When used as conductive plastics, 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, urea. -Melamine resin is engineering plastic for general-purpose plastics such as phenol resin, unsaturated polyester resin, hard vinyl chloride resin, ABS resin, AS resin, and engineering plastics are such as epoxy resin, polyacetal, polycarbonate, polybutylene Terephthalate, polyethylene terephthalate, polyphenylene ether, polyphenylene sulfide, polysulfone, fluororesin, super engineering Examples of the plastics include diallyl phthalate resin, silicon resin, polyimide resin, polyamideimide, bismaleimide triazine, polyamino bismaleimide, olefin vinyl alcohol copolymer, polyoxybenzylene, polymethylpentene, polyethersulfone, and polyether. Examples thereof include imide, polyarylate, polyether ether ketone, and the like. The compounding quantity of the acicular 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 with respect to 100 parts by weight of the resin.
[0019]
When the acicular antimony-containing tin oxide fine powder of the present invention is used as a conductive paint or a magnetic paint, various binders such as polyvinyl alcohol resin, vinyl chloride-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, fluororesin, silicone resin, petroleum resin, shellac, rosin derivative, rubber derivative, etc. It mix | blends with a system resin etc., and is disperse | distributed in water or a solvent. The amount of acicular conductive antimony-containing tin oxide fine powder blended 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, the coating is applied to an insulating substrate such as paper or a polymer film, so that the conductive coating is light and transparent on the substrate and has excellent surface smoothness and adhesion. Films can be formed into various antistatic coatings, electrostatic recording paper, electrophotographic copying paper, and the like. In addition, when the acicular conductive antimony-containing tin oxide fine powder of the present invention is applied to an aqueous coating, the tin oxide fine powder or the soluble salts obtained from the production process of the tin oxide fine powder are removed. In the case where an aqueous dispersion is prepared by dispersing the treated cake in an aqueous medium and the aqueous dispersion is used for coating, the dispersion energy at the time of coating or the dehydration and drying energy in the tin oxide fine powder production process It is preferable in order to reduce this. 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.
[0020]
On the other hand, in the case of a paint used for the production of a magnetic recording medium, improvement in adhesion between the nonmagnetic support and the magnetic layer, prevention of charging of the magnetic recording medium, enhancement of film strength, thinning of the magnetic layer, It is useful for improving the dispersibility and surface smoothness of the lower nonmagnetic layer accompanying the surface smoothing. In particular, in recent years, the recording wavelength tends to be shortened with an increase in the recording density of magnetic recording, and coupled with this, there is a further demand for a thinner magnetic layer of the magnetic recording medium. However, when the magnetic layer is thinned, the influence of the support tends to appear on the magnetic surface, and deterioration of electromagnetic conversion characteristics is inevitable. For this purpose, for example, by providing a nonmagnetic undercoat layer on the surface of the nonmagnetic support and then providing the magnetic layer as an upper layer, the influence of the surface roughness of the support is eliminated, and the magnetic layer is thinned to increase the thickness. There is a method for achieving output. The filling ratio of the needle-shaped conductive antimony-containing tin oxide fine powder of the present invention into the lower nonmagnetic layer is about 20 to 80% in terms of volume filling rate.
[0021]
When used as a conductive rubber, for example, silicone rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, butadiene-acrylonitrile rubber, ethylene-propylene-diethane polymer, ethylene-propylene rubber, fluorine rubber, ethylene- It is blended with conventionally known ones such as vinyl acetate copolymer, chlorinated polyethylene, acrylic rubber, chloroprene rubber, urethane rubber, polysulfide rubber, chlorosulfonated polyethylene rubber and epichlorohydrin rubber.
[0022]
When used as a conductive fiber, it is blended in a fusible fiber such as a polyamide resin, a polyester resin, a polyolefin resin, a polyvinyl resin, or a polyether resin.
[0023]
The conductive composition thus obtained has high conductivity with a smaller blending amount with respect to the resin binder than a conductive composition containing a conventional spherical or needle-shaped conductive powder. At the same time, it has excellent transparency and is economically advantageous. Since such a small amount is sufficient, it can be used without causing a decrease in the strength of the binder. When a high-concentration conductive paint is used, desired conductivity can be obtained even with a thin coating. In particular, it can be an unprecedented bluish tone with excellent electrical conductivity and transparency.
[0024]
【Example】
Example 1
A solution in which 500 g of stannic chloride pentahydrate is dissolved in 500 ml of 3N hydrochloric acid aqueous solution in 5 l of pure water at 90 ° C., 17.4 ml of sodium silicate aqueous solution (308 g / l as SiO 2 ), sodium hydroxide solution, Were added in parallel over 20 minutes to maintain the pH of the system at 7-7.5 to produce a coprecipitate. 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. After drying the obtained cake at 110 ° C. for 12 hours, 20 parts by weight of sodium chloride was added to 100 parts by weight of the dried product, and both were uniformly mixed and ground. This mixture was baked in an electric furnace at 900 ° C. for 1 hour. Thereafter, the obtained baked product was immersed in a hydrofluoric acid aqueous solution to remove soluble salts, and then the obtained cake was repulped into 5 l of pure water, heated to 90 ° C., and antimony trichloride 3 .36 g (Sb / Sn atomic ratio: 1/100) dissolved in 300 ml of 3N hydrochloric acid aqueous solution and sodium hydroxide solution in parallel for 20 minutes so as to maintain the pH of the system at 7 to 7.5 Then, hydrous antimony oxide was deposited on the acicular tin oxide. 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 at 900 ° C. for 1 hour in an electric furnace, and pulverized with a pulverizer to obtain fine acicular antimony-containing tin oxide powder of the present invention. This product has a minor axis average particle size of 0.015 μm, a major axis average particle size of 0.50 μm, an aspect ratio of 33, a powder resistance of 18.5 Ωcm, and a powder color (pressing pressure 200 kg / cm 2 ). The b value was -5.8 and the L value was 82.3.
[0025]
Example 2
In Example 1, the acicular antimony-containing tin oxide fine powder of the present invention was treated in the same manner as in the same example except that the baking temperature of the fractionally recovered cake after precipitation of hydrous antimony was 1000 ° C. Got. The short axis average particle diameter of this was 0.024 μm, the long axis average particle diameter was 0.52 μm, the aspect ratio was 22, the powder resistance was 31.7 Ωcm, and the powder color (pressing pressure 200 Kg / cm 2 ) The b value was −4.6, and the L value was 85.9.
[0026]
Example 3
In Example 1, except that the amount of antimony trichloride used was 16.82 g (Sb / Sn atomic ratio: 5/100), the needle-like conductivity of the present invention was treated in the same manner as in the same example. An antimony-containing tin oxide fine powder was obtained. The minor axis average particle diameter is 0.014 μm, the major axis average particle diameter is 0.50 μm, the aspect ratio is 36, the powder resistance is 8.0 Ωcm, and the powder color (pressing pressure 200 kg / cm 2 ). The b value was -6.0 and the L value was 81.0.
[0027]
Comparative Example In 5 l of pure water at 90 ° C., a solution of 500 g of stannic chloride pentahydrate and 3.36 g of antimony trichloride in 500 ml of 3N hydrochloric acid aqueous solution, an aqueous sodium silicate solution (308 g / l as SiO 2 ) 17.4 ml and sodium hydroxide solution were added in parallel over 20 minutes to maintain the pH of the system at 7-7.5 to produce a coprecipitate. 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 15000 Ωcm. After drying the obtained cake at 110 ° C. for 12 hours, 20 parts by weight of sodium chloride was added to 100 parts by weight of the dried product, and both were uniformly mixed and ground. This mixture was baked in an electric furnace at 900 ° C. for 1 hour. Thereafter, the obtained fired product was immersed in a hydrofluoric acid aqueous solution to remove soluble salts, followed by drying and pulverization to obtain acicular antimony-containing tin oxide fine powder. This product has a minor axis average particle size of 0.011 μm, a major axis average particle size of 0.50 μm, an aspect ratio of 45, a powder resistance of 32.5 Ωcm, and a powder color (pressing pressure 200 kg / cm 2 ). The b value was -9.4, and the L value was 73.6.
[0028]
In addition, each particle diameter, powder resistance, and powder color in each Example and Comparative Example were measured by the following methods.
(1) The weight average particle diameter was obtained by observing an electron micrograph (magnification of 100,000 times), and the aspect ratio was calculated based on the weight average particle diameter.
(2) The specific resistance (Ωcm) of each sample powder under a pressure of 100 Kg / cm 2 was measured (digital multimeter: Model 2502A, manufactured by Yokogawa Hokushin Electric Co., Ltd.).
(3) 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 powder color (color computer, SM-7-IS-2B type, manufactured by Suga Test Instruments Co., Ltd.) ) Was measured.
[0029]
【The invention's effect】
INDUSTRIAL APPLICABILITY The present invention can provide a needle-like conductive antimony-containing tin oxide fine powder having a small bluish color tone, high brightness, excellent transparency and conductivity, and an industrially advantageous production method thereof.
Claims (1)
Priority Applications (11)
Application Number | Priority Date | Filing Date | Title |
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JP18093795A JP3609159B2 (en) | 1995-06-23 | 1995-06-23 | Acicular conductive antimony-containing tin oxide fine powder and method for producing the same |
TW084113464A TW455568B (en) | 1994-12-27 | 1995-12-16 | Process for the preparation of acicular electroconductive tin oxide fine particles |
TW089122844A TW440544B (en) | 1994-12-27 | 1995-12-16 | Electroconductive composition |
EP95119987A EP0719730B1 (en) | 1994-12-27 | 1995-12-18 | Acicular electroconductive tin oxide fine particles and process for producing same |
DE69511057T DE69511057T2 (en) | 1994-12-27 | 1995-12-18 | Needle-shaped, electrically conductive tin oxide particles and process for their production |
AU40493/95A AU693958B2 (en) | 1994-12-27 | 1995-12-18 | Acicular electroconductive tin oxide fine particles and process for producing same |
CA002166020A CA2166020C (en) | 1994-12-27 | 1995-12-22 | Acicular electroconductive tin oxide fine particles and process for producing same |
US08/576,909 US5575957A (en) | 1994-12-27 | 1995-12-22 | Acicular electroconductive tin oxide fine particles and process for producing same |
KR1019950056590A KR100394889B1 (en) | 1994-12-27 | 1995-12-26 | Needle-shaped electrically conductive tin oxide fine particles and preparation method thereof |
CN95120120A CN1053643C (en) | 1994-12-27 | 1995-12-27 | Pin shape conduction tin oxide granule and making method thereof |
US08/688,287 US5705098A (en) | 1994-12-27 | 1996-07-29 | Acicular electroconductive tin oxide fine particles and process for producing same |
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JP18093795A JP3609159B2 (en) | 1995-06-23 | 1995-06-23 | Acicular conductive antimony-containing tin oxide fine powder and method for producing the same |
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EP1245968B1 (en) | 2001-03-30 | 2004-06-30 | JSR Corporation | Laminate comprising a needle-like antimony-containing tin oxide and antireflection film comprising the same |
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 |
FR2874927B1 (en) | 2004-09-03 | 2012-03-23 | Kansai Paint Co Ltd | PAINT COMPOSITIONS, METHODS FOR APPLYING THESE PAINTS AND COATED PARTS THEREOF. |
US8216490B2 (en) | 2005-10-18 | 2012-07-10 | Kansai Paint Co., Ltd. | Aqueous primer composition and a process for the application of the same |
JP5601760B2 (en) | 2007-06-29 | 2014-10-08 | 関西ペイント株式会社 | Aqueous primer composition and coating method using the composition |
JP5674354B2 (en) * | 2009-06-30 | 2015-02-25 | 三菱マテリアル株式会社 | Conductive acicular antimony tin oxide fine powder and method for producing the same |
JP5416532B2 (en) * | 2009-09-30 | 2014-02-12 | 三菱マテリアル株式会社 | Acicular tin oxide fine powder and method for producing the same |
JP6016494B2 (en) * | 2011-12-19 | 2016-10-26 | 三井金属鉱業株式会社 | Composite oxide powder, aqueous dispersion and oil dispersion |
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1995
- 1995-06-23 JP JP18093795A patent/JP3609159B2/en not_active Expired - Lifetime
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