JP2583536B2 - Method for producing conductive zinc oxide fine powder - Google Patents
Method for producing conductive zinc oxide fine powderInfo
- Publication number
- JP2583536B2 JP2583536B2 JP62284636A JP28463687A JP2583536B2 JP 2583536 B2 JP2583536 B2 JP 2583536B2 JP 62284636 A JP62284636 A JP 62284636A JP 28463687 A JP28463687 A JP 28463687A JP 2583536 B2 JP2583536 B2 JP 2583536B2
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- Prior art keywords
- fine powder
- zinc oxide
- weight
- parts
- oxide
- Prior art date
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- Inorganic Compounds Of Heavy Metals (AREA)
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Description
【発明の詳細な説明】 [産業上の利用分野] 本発明は、導電性付与成分として作用すると共に、平
均粒子径が0.10μm以下であって乾燥膜に透明性を与え
ることができ、しかも分散性の優れた導電性酸化亜鉛微
粉末の製造方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention not only acts as a conductivity-imparting component, but also has an average particle diameter of 0.10 μm or less, can impart transparency to a dried film, and can be dispersed. The present invention relates to a method for producing a conductive zinc oxide fine powder having excellent properties.
[従来の技術] 導電性酸化亜鉛は、静電記録紙、通電感熱記録紙、放
電破壊記録紙、電子写真紙等の如き様々の情報産業記録
紙や塗料、接着剤、インキ、各種樹脂等における導電性
顔料や帯電防止成分、更には電子写真用現像剤などとし
て広汎な用途を有しており、殊にこの粉末は白色であっ
て他の着色剤により容易に着色し得るという特徴も有し
ているところから、工業的にも広く活用されている。[Conventional technology] Conductive zinc oxide is used in various information industry recording papers such as electrostatic recording papers, current-sensitive recording papers, discharge breakdown recording papers, electrophotographic papers, paints, adhesives, inks, and various resins. It has a wide range of uses as conductive pigments and antistatic components, and further as a developer for electrophotography, and especially has the characteristic that this powder is white and can be easily colored by other colorants. It is widely used industrially.
ところで導電性酸化亜鉛は、非導電性酸化亜鉛を酸化
アルミニウム等によって賦活化することにより得られる
が、単に非導電性酸化亜鉛と酸化アルミニウムを混合し
加熱処理するだけで良導電性のものが得られるとは限ら
ず、処理条件によって導電率はかなり変わってくるの
で、導電率の向上を目的として様々の提案がなされてい
る。たとえば特公昭55−19896号公報や同55−19897号公
報には、非導電性酸化亜鉛とアルミニウム化合物を固定
炭素の存在下で加熱処理する方法が開示され、また特開
昭55−162477号公報には、酸化亜鉛を有機アルミニウム
化合物等と共に湿式処理した後乾燥、粉砕し、最後に非
酸化性雰囲気下で焼成する方法、等が開示されている。
これらの方法は、導電性付与という本来の目的からすれ
ばいずれも優れた方法として評価されるが、反面粒径が
大きいため透明導電膜形成用の素材としては適性を欠
く。また特開昭56−69266号公報には、水溶性亜鉛塩とA
l2O3やSnO2等の生成源となる水溶性金属塩から炭酸アル
カリを用いて共沈させ、次いで非酸化性雰囲気下で焼成
することにより微粉末状の導電性酸化亜鉛を製造する方
法が開示されている。しかしながらこの方法はZnCl2等
の塩を用いた場合のC1イオン等の除去が煩雑で手数を要
するばかりでなく、粒径はせいぜい1〜1.3μm程度で
あって透明導電膜用としての要求特性を満たすものとは
言えない。By the way, conductive zinc oxide is obtained by activating non-conductive zinc oxide with aluminum oxide or the like, but a good conductive material can be obtained simply by mixing non-conductive zinc oxide and aluminum oxide and heating. The conductivity is not always limited, and the conductivity varies considerably depending on the processing conditions. Therefore, various proposals have been made for the purpose of improving the conductivity. For example, Japanese Patent Publication Nos. 55-19896 and 55-19897 disclose a method of heat-treating a non-conductive zinc oxide and an aluminum compound in the presence of fixed carbon. Discloses a method in which zinc oxide is wet-processed together with an organoaluminum compound or the like, dried, pulverized, and finally fired in a non-oxidizing atmosphere.
Any of these methods is evaluated as an excellent method from the original purpose of imparting conductivity, but is not suitable as a material for forming a transparent conductive film due to a large particle diameter. JP-A-56-69266 discloses a water-soluble zinc salt and A
How l 2 O 3 or coprecipitated with the alkali carbonate from water-soluble metal salt serving as a generation source of SnO 2 or the like, and then to produce a fine powder of electrically conductive zinc oxide by firing in a non-oxidizing atmosphere Is disclosed. However, this method not only requires complicated and time-consuming removal of C1 ions and the like when using a salt such as ZnCl 2 , but also has a particle size of at most about 1 to 1.3 μm, which is a characteristic required for a transparent conductive film. It cannot be said to be satisfied.
本出願人はこの様な状況の下で、透明導電膜用として
の特性を満たす粒度構成の導電性酸化亜鉛微粉末の製法
を確立すべくかねてより研究を行なっているが、かかる
研究の一環として先に特開昭58−161923号公報に記載の
方法を開発した。この方法は、酸化亜鉛を、賦活剤とし
て作用するアルミニウム塩および侵食剤(崩壊剤)とし
て作用する炭酸アンモニウム等との共存下に水分散系で
処理し、脱水、乾燥後600〜1000℃で焼成するものであ
り、この方法によると、酸化亜鉛崩壊剤の作用によって
酸化亜鉛は多孔質化すると共に微細化し、賦活剤との混
合も緻密且つ均一に行なわれるところから、従来の導電
性酸化亜鉛に較べるとかなり粒子径の小さいものを得る
ことができる。しかしながらこの方法にしても得られる
導電性酸化亜鉛の粒径は、BET法により求められる比表
面積径で0.15μm程度が限度であり、透明導電膜用とし
ての特性を完全に満たすものとは言えない。Under such circumstances, the present applicant has been conducting research for the purpose of establishing a method for producing a conductive zinc oxide fine powder having a particle size composition that satisfies characteristics for a transparent conductive film. The method described in JP-A-58-161923 was previously developed. In this method, zinc oxide is treated with an aqueous dispersion in the presence of an aluminum salt that acts as an activator and ammonium carbonate that acts as an erosion agent (disintegrant), dehydrated, dried, and then calcined at 600 to 1000 ° C. According to this method, the zinc oxide is made porous and fine by the action of the zinc oxide disintegrant, and the mixing with the activator is performed densely and uniformly. In comparison, it is possible to obtain particles having a considerably small particle size. However, even with this method, the particle size of the conductive zinc oxide obtained is limited to about 0.15 μm in specific surface area diameter required by the BET method, and cannot be said to completely satisfy the properties for a transparent conductive film. .
即ち顔料充填系で透明性を得る為の手段としては、顔
料の粒子径を可視光線よりも小さくするか、あるいは塗
料等ではビヒクル成分である樹脂との屈折率の差をでき
るだけ小さくすることが必要とされており、顔料自体の
特性としては粒子径を比表面積径(以下、特記しない限
りBET法により求められる値を意味する)で0.10μm以
下とすることにより透明性付与の目的は達成されるが、
現在のところその様な微細粒度構成の導電性酸化亜鉛は
得られていない。That is, as means for obtaining transparency in a pigment-filled system, it is necessary to make the particle size of the pigment smaller than visible light, or to minimize the difference in the refractive index from the resin that is the vehicle component in paints and the like. The purpose of imparting transparency is achieved by setting the particle diameter of the pigment itself to 0.10 μm or less in terms of the specific surface area (hereinafter, a value determined by the BET method unless otherwise specified) as a characteristic of the pigment itself. But,
At present, conductive zinc oxide having such a fine particle size composition has not been obtained.
この様なところから、透明性の要求される導電性粉末
としては、0.10μm以下の比表面積径の微粉末として得
ることのできるSnO2系導電粉末やIn2O3系導電粉末が常
用されているが、いずれも非常に高価であって経済性や
汎用性に問題があり、しかも前者は青味を帯びているば
かりでなく塗膜中に混在させたときに紫外線等の作用で
更に着色し易いといった問題がある。From such a place, as the conductive powder to be transparency requirements, it generally used SnO 2 Keishirubeden powder or In 2 O 3 Keishirubeden powder which can be obtained as a fine powder of the following specific surface area diameter 0.10μm However, both are very expensive and have problems in economy and versatility.Moreover, the former is not only bluish, but also becomes more colored by the action of ultraviolet rays when mixed in the coating film. There is a problem that it is easy.
[発明が解決しようとする問題点] 本発明はこの様な事情に着目してなされたものであっ
て、その目的は、工業的に安価に入手し得る酸化亜鉛を
主原料として、微細且つ安定で導電性及び分散性に優れ
しかも被膜に透明性を与えることのできる様な導電性酸
化亜鉛微粉末の製造方法を提供しようとするものであ
る。[Problems to be Solved by the Invention] The present invention has been made in view of such circumstances, and its object is to use a zinc oxide that can be obtained industrially at a low cost as a main raw material to obtain a fine and stable material. An object of the present invention is to provide a method for producing a conductive zinc oxide fine powder which is excellent in conductivity and dispersibility and can impart transparency to a coating film.
[問題点を解決するための手段] 上記の目的を達成することのできた本発明に係る製造
方法の構成は、 [I]非導電性酸化亜鉛:100重量部、 [II]水溶性乃至水分散性アルミニウム化合物:酸化ア
ルミニウム換算で0.1〜10重量部、 [III]炭酸アンモニウム、重炭酸アンモニウム、硝
酸、アンモニウムおよび尿素よりなる群から選択される
1種以上の化合物:5〜100重量部 の三成分を、比表面積径が0.10μm以下である酸化物微
粉末および/または珪酸塩微粉末の存在下に水分散系で
撹拌処理し、脱水後非酸化性雰囲気下に600℃以下の温
度で加熱処理するところに要旨を有するものである。[Means for Solving the Problems] The structure of the production method according to the present invention which can achieve the above object is as follows: [I] non-conductive zinc oxide: 100 parts by weight, [II] water solubility or water dispersion Aluminum compound: 0.1 to 10 parts by weight in terms of aluminum oxide, [III] one or more compounds selected from the group consisting of ammonium carbonate, ammonium bicarbonate, nitric acid, ammonium and urea: 5 to 100 parts by weight Is stirred in an aqueous dispersion in the presence of an oxide fine powder and / or a silicate fine powder having a specific surface area of 0.10 μm or less, and after dehydration, heat-treated at a temperature of 600 ° C. or less in a non-oxidizing atmosphere. It has a gist where it does.
[作用] 本発明に係る製造方法は、前記特開昭58−161923号公
報に開示した様に、[I]フランス法やアメリカ法等に
よって製造された酸化亜鉛を、[II]水溶性乃至水分散
性(以下単に水溶性ということがある)アルミニウム化
合物および[III]炭酸アンモニウム、重炭酸アンモニ
ウム、硝酸アンモニウム、尿素よりなる群から選択され
る侵食剤(崩壊剤)の1種又は2種以上の共存下に水分
散系で撹拌処理し、脱水後加熱処理する方法を基本とす
るものであり、この方法をより詳細に説明すると次の通
りである。[Action] As disclosed in the above-mentioned JP-A-58-161923, [I] zinc oxide produced by the French method or the American method is converted into [II] water-soluble or water-soluble Coexistence of one or more of a dispersible (hereinafter sometimes simply referred to as water-soluble) aluminum compound and [III] an erosion agent (disintegrant) selected from the group consisting of ammonium carbonate, ammonium bicarbonate, ammonium nitrate and urea The method is based on a method in which a stirring treatment is carried out in an aqueous dispersion system, and a heat treatment is carried out after dehydration. This method will be described in more detail as follows.
即ちフランス法等によって得られる非導電性酸化亜鉛
[I]の粒度構成は一般に0.2〜0.8μm程度であり、X
線回折によると六方晶系の回折図を示すが、この非導電
性酸化亜鉛[I]を炭酸アンモニウム等の崩壊剤[II
I]と共に水分散系で処理すると六方晶系の結晶構造が
くずれ、比表面積径にして0.01μm程度以下の微粒子と
なる。この微粒子状酸化亜鉛はもはや六方晶径の回折特
性を示さず、非晶質状のものとなる。このものは非常に
微細で表面活性の高いものであり、この存在系に導電性
賦活剤としてアルミニウム化合物[II]を共存させてお
くとこれらが粒子表面に付着し、その後の乾燥乃至焼成
工程でアルミニウムの一部が酸化亜鉛の結晶格子内へ取
り込まれ、全体として導電性を示す様になるものと考え
られている。That is, the particle size composition of the non-conductive zinc oxide [I] obtained by the French method or the like is generally about 0.2 to 0.8 μm.
According to X-ray diffraction, a hexagonal diffraction pattern is shown. This non-conductive zinc oxide [I] is converted to a disintegrant [II] such as ammonium carbonate.
When treated with an aqueous dispersion together with [I], the hexagonal crystal structure is broken and fine particles having a specific surface area of about 0.01 μm or less are obtained. The particulate zinc oxide no longer exhibits a hexagonal diameter diffraction characteristic and becomes amorphous. This is very fine and has a high surface activity. If an aluminum compound [II] is coexistent as a conductive activator in this existing system, these adhere to the particle surface, and in the subsequent drying or firing step, It is considered that part of the aluminum is taken into the crystal lattice of zinc oxide, and as a whole becomes conductive.
そして上記の様な目的で使用される崩壊剤[III]と
しては炭酸アンモニウム、重炭酸アンモニウム、硝酸ア
ンモニウムから選択されるアンモニウム塩、あるいは加
温することによりアンモニアを生成する尿素が挙げら
れ、これらは濾過、乾燥乃至加熱処理工程で除去される
ので、最終製品の導電性等には殆んど影響を与えない。
該崩壊剤[III]の上記添加目的を有効に達成するため
の添加量は、酸化亜鉛100重量部に対して5〜100重量
部、より好ましくは10〜50重量部であり、5重量部未満
では結晶の崩壊が不十分で微細化の目的が達成されず、
またそれらの結晶崩壊作用は100重量部で飽和するので
それ以上の添加は全く無駄である。Examples of the disintegrant [III] used for the above purpose include ammonium salts selected from ammonium carbonate, ammonium bicarbonate, and ammonium nitrate, and urea that generates ammonia when heated. Since it is removed in the drying or heat treatment process, it hardly affects the conductivity and the like of the final product.
The addition amount of the disintegrant [III] for effectively achieving the above-mentioned addition purpose is 5 to 100 parts by weight, more preferably 10 to 50 parts by weight, and preferably less than 5 parts by weight based on 100 parts by weight of zinc oxide. In this case, the crystal disintegration is insufficient and the purpose of miniaturization is not achieved,
Further, since their crystal disintegration effect is saturated at 100 parts by weight, further addition is useless.
尚上記崩壊剤のうち炭酸アンモニウムや重炭酸アンモ
ニウムは、水分散系にアンモニアと炭酸ガスを吹込むこ
とによってその場で生成させることもできる。Incidentally, among the above disintegrants, ammonium carbonate and ammonium bicarbonate can also be generated in situ by blowing ammonia and carbon dioxide gas into the aqueous dispersion.
また導電性賦活剤として用いられる水溶性アルミニウ
ム化合物[II]は、前述の如く酸化亜鉛に導電性を付与
する為のものであり、水系で微細な酸化亜鉛に万遍無く
均一に分布し得る様、たとえば蟻酸塩、酢酸塩、ハロゲ
ン化物、水酸化物、硫酸塩、硝酸塩の様な水溶性乃至水
分散性のものが選択して使用される。そしてこれらの水
溶性アルミニウム化合物のうち水酸化物を除くものは、
処理系内へ添加される前記炭酸アンモニウム等の一部に
より中和され、水酸化物を生成して酸化亜鉛スラリー内
へ均一に混入し、また水酸化物を用いた場合はそれ自身
が微細な粒状物として水系内へ均一に分布し、その後の
乾燥・焼成工程で酸化アルミニウムとなって酸化亜鉛微
粉末中へ万遍無く分布して導電性を与える。最終製品に
満足のいく導電性を付与する為には、アルミニウム化合
物を酸化アルミニウム換算で酸化亜鉛100重量部に対し
0.1〜10重量部、より好ましくは0.5〜5重量部添加しな
ければならず、0.1重量部未満では導電性不足となり、
一方10重量部を超えても導電性はそれ以上改善されず、
場合によっては最終の焼成粉末が着色したり顔料として
の特性に悪影響が表われることがある。The water-soluble aluminum compound [II] used as the conductive activator is for imparting conductivity to the zinc oxide as described above, and can be uniformly distributed in fine zinc oxide in an aqueous system. For example, water-soluble or water-dispersible ones such as formate, acetate, halide, hydroxide, sulfate and nitrate are selectively used. And among these water-soluble aluminum compounds, except for the hydroxide,
Neutralized by a part of the ammonium carbonate or the like added into the treatment system, generates hydroxide and is uniformly mixed into the zinc oxide slurry, and when hydroxide is used, itself is fine. It is uniformly distributed as particulate matter in the aqueous system, becomes aluminum oxide in the subsequent drying and firing steps, and is evenly distributed in the zinc oxide fine powder to give conductivity. In order to impart satisfactory conductivity to the final product, the aluminum compound must be converted to aluminum oxide based on 100 parts by weight of zinc oxide.
0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight must be added.
On the other hand, even if it exceeds 10 parts by weight, the conductivity is not further improved,
In some cases, the final calcined powder may be colored or adversely affect its properties as a pigment.
ところで先の公開公報に開示した方法では、上記の
[I]非導電性酸化亜鉛、[II]水分散性アルミニウム
化合物(賦活剤)及び[III]炭酸アルミニウム等の崩
壊剤の三者を、水分散系で常温〜100℃程度(但し崩壊
剤として尿素を用いた場合は分解促進のため80〜100℃
に加温)で30分〜90分程度撹拌処理し、脱水、乾燥後非
酸化性雰囲気下に600〜1000℃程度で焼成を行なって導
電性酸化亜鉛微粉末を得るものであり、崩壊剤の添加効
果が有効に発揮される結果、従来の導電性酸化亜鉛粉末
に比べると微細なものを得ることができる。By the way, in the method disclosed in the above-mentioned publication, three of the above [I] non-conductive zinc oxide, [II] a water-dispersible aluminum compound (activator) and [III] aluminum carbonate are mixed with water. Normal temperature to about 100 ° C in the dispersion system (However, when urea is used as a disintegrant, it is 80 to 100 ° C to promote decomposition.
The mixture is heated for about 30 minutes to 90 minutes, dehydrated, dried, and calcined at about 600 to 1000 ° C. in a non-oxidizing atmosphere to obtain conductive zinc oxide fine powder. As a result of the effective addition effect, a finer powder can be obtained as compared with the conventional conductive zinc oxide powder.
しかしその後更に研究を進めるうち、上記の方法では
崩壊剤により折角微細化した酸化亜鉛が最終の乾燥乃至
焼成工程で再び凝集若しくは焼結するため、結局のとこ
ろ焼成物の粒径は原料として用いた非導電性酸化亜鉛粉
末の粒径(0.2〜0.8μm)付近まで戻り、透明性を発揮
し得る様な粒度構成のものを得ることはできなかった。However, after further research, the zinc oxide refined by the disintegrant was reagglomerated or sintered in the final drying or firing step, and the particle size of the fired material was used as the raw material after all. It returned to the vicinity of the particle size (0.2 to 0.8 μm) of the non-conductive zinc oxide powder, and it was not possible to obtain a particle having a particle size composition capable of exhibiting transparency.
即ち透明性を確保し得る粉末の粒径は前述の如く可視
光線の波長よりも小さい0.10μm程度以下のものである
から、こうした要求を満たすには、乾燥・焼成時の凝集
もしくは焼結を阻止する必要がある。That is, since the particle size of the powder that can ensure transparency is about 0.10 μm or less, which is smaller than the wavelength of visible light, as described above, in order to satisfy such requirements, aggregation or sintering during drying and firing is prevented. There is a need to.
そこで上記の様な観点から更に研究を重ねた結果、
[I]非導電性酸化亜鉛、[II]賦活剤(水溶性アルミ
ニウム化合物)及び[III]崩壊剤の三成分を水分散系
で撹拌処理する際に、該水分散系に比表面積系が0.10μ
m以下である酸化物微粉末および/または珪酸塩微粉末
を共存せしめ、且つ脱水後の熱処理温度を600℃以下に
抑えてやれば、脱水・乾燥乃至熱処理時における導電性
酸化亜鉛微粒子同士の凝集が阻止され、0.10μm以下の
非常に微細なものとなることが明らかとなった。Therefore, as a result of further research from the above viewpoint,
When the three components of [I] non-conductive zinc oxide, [II] activator (water-soluble aluminum compound) and [III] disintegrant are stirred in an aqueous dispersion, the specific surface area of the aqueous dispersion is 0.10. μ
m or less, and the heat treatment temperature after dehydration is kept at 600 ° C. or less, agglomeration of conductive zinc oxide fine particles during dehydration / drying or heat treatment. Was prevented, and it became clear that the particles were very fine having a size of 0.10 μm or less.
酸化物微粉末および/または珪酸塩微粉末の共存によ
って酸化亜鉛粒子の凝集が阻止される理由については完
全に解明し得た訳ではないが、酸化物微粉末および/ま
たは珪酸塩微粉末が酸化亜鉛粒子の間に介在することに
よって酸化亜鉛粒子同士の凝集付着が抑えられ、加熱処
理温度を600℃以下に抑えたことによる効果とも相まっ
て粒成長が抑制されたものと推定している。こうした凝
集防止効果を発揮する酸化物微粉末および/または珪酸
塩微粉末の具体例としてはシリカ、アルミナ、チタニア
等の酸化物微粉末や各種珪酸塩微粉末等が挙げられ、た
とえばコロイダルシリカやアルミナゾルの様に粒径が小
さいものほど優れた凝集阻止効果を発揮する。尚こられ
の無機質微粉末自身の体積抵抗率は1010Ωcm以上であっ
て導電性に良い影響を及ぼし得る様なものではなく、し
かも600℃以下の温度では酸化亜鉛と反応して導電性を
高めるといった作用も有しておらず、これらは専ら凝集
防止剤としての機能を果たすものである。該酸化物微粉
末および/または珪酸塩微粉末の添加効果は、特にコロ
イダルシリカの様に粒径の非常に小さいものであれば極
く微量で発揮されるので明確な下限値を定めることはで
きないが、市販のコロイダルシリカを基準にすれば、酸
化亜鉛100重量部に対して0.05重量部以上、より好まし
くは0.1重量部以上添加することにより目的を果たすこ
とができる。一方、酸化物微粉末および/または珪酸塩
微粉末の添加量が多過ぎると導電性に悪影響が現われて
くるので、添加量は酸化亜鉛100重量部に対して10重量
部以下、より好ましくは5重量部以下に抑えるべきであ
る。The reason why the aggregation of zinc oxide particles is prevented by the coexistence of the oxide fine powder and / or the silicate fine powder has not been completely elucidated, but the oxide fine powder and / or the silicate fine powder cannot be oxidized. It is presumed that the intercalation between the zinc particles suppresses the cohesion and adhesion between the zinc oxide particles, and that the grain growth is suppressed in combination with the effect of suppressing the heat treatment temperature to 600 ° C. or lower. Specific examples of the oxide fine powder and / or silicate fine powder exhibiting such an aggregation preventing effect include oxide fine powders of silica, alumina, titania and the like, and various silicate fine powders, such as colloidal silica and alumina sol. The smaller the particle size is, the more excellent the aggregation inhibiting effect is. The volume resistivity of the inorganic fine powder itself is 10 10 Ωcm or more, which does not seem to have a good effect on conductivity, and at a temperature of 600 ° C or less, it reacts with zinc oxide to increase conductivity. They do not have the effect of increasing the concentration, and they exclusively function as anti-agglomeration agents. The effect of the addition of the oxide fine powder and / or the silicate fine powder is extremely small if the particle size is very small like colloidal silica, so that a clear lower limit cannot be determined. However, based on commercially available colloidal silica, the purpose can be achieved by adding at least 0.05 part by weight, more preferably at least 0.1 part by weight, based on 100 parts by weight of zinc oxide. On the other hand, if the added amount of the oxide fine powder and / or the silicate fine powder is too large, the conductivity is adversely affected. Therefore, the added amount is not more than 10 parts by weight, more preferably not more than 5 parts by weight, per 100 parts by weight of zinc oxide. It should be kept below parts by weight.
また仮に適量の酸化物微粉末および/または珪酸塩微
粉末を添加した場合であっても、加熱処理温度が600℃
を超えると酸化亜鉛微粒子同士の融着等によって二次凝
集が起こって粒子が粗大化するので、加熱処理は600℃
以下で行なわれなければならない。加熱処理温度の下限
は特に規定していないが、完全乾燥乃至焼成という本来
の目的を果たすためには200℃以上、より確実なのは300
℃以上である。Even if an appropriate amount of oxide fine powder and / or silicate fine powder is added, the heat treatment temperature is 600 ° C.
If the temperature exceeds 600 ° C., secondary agglomeration occurs due to the fusion of the zinc oxide fine particles and the particles become coarse.
It must be done below. Although the lower limit of the heat treatment temperature is not particularly defined, it is more than 200 ° C. in order to achieve the original purpose of complete drying or baking, and it is more certain that the temperature is more than 300 ° C.
° C or higher.
尚該加熱処理のもう一つの重要な役割りは、賦活剤添
加による導電性を発現させるところにあり、その為には
加熱処理を非酸化性雰囲気(具体的には水素、窒素、ア
ンモニア等のガス雰囲気)で行なわれなければならず、
酸化性雰囲気で加熱処理を行なったのでたとえ適量の賦
活剤を添加したとしても導電性を与えることはできな
い。Another important role of the heat treatment is to exhibit conductivity by the addition of an activator. For this purpose, the heat treatment is performed in a non-oxidizing atmosphere (specifically, hydrogen, nitrogen, ammonia, etc.). Gas atmosphere)
Since the heat treatment was performed in an oxidizing atmosphere, even if an appropriate amount of an activator was added, conductivity could not be given.
しかも酸化亜鉛は本来紫外線領域である350〜400nm付
近の光に対して吸収帯を有しているが、本発明の導電性
酸化亜鉛もその例外ではなく紫外線領域に吸収帯を有し
ており、紫外線遮蔽材としての作用も併せ有している。Moreover, zinc oxide originally has an absorption band for light around 350 to 400 nm, which is an ultraviolet region, but the conductive zinc oxide of the present invention is not exceptional and has an absorption band in the ultraviolet region, It also has a function as an ultraviolet shielding material.
以下実施例を挙げて本発明を具体的に説明するが、本
発明はもとより下記の実施例によって制限を受けるもの
ではない。Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples.
[実施例] 下記第1表に示す原料配合量に準じて、所定量の崩壊
剤を500ccの水に溶解し、別に水50ccに賦活剤を溶解し
た溶液を上記崩壊剤含有水溶液に加えて混合する。この
混合液を別途調製したフランス法亜鉛華(平均比表面積
径:0.3μm)100gの水200cc分散液に投入し、60〜90℃
に昇温した後所定量の酸化物微粉末および/または珪酸
塩微粉末を加えて同温度で1時間撹拌する。撹拌終了後
濾過・水洗し、乾燥後、水素、窒素またはアンモニアガ
ス雰囲気中200〜900℃で30分〜2時間加熱処理し、導電
性の酸化亜鉛微粉末を得た。[Example] A predetermined amount of a disintegrant was dissolved in 500 cc of water according to the raw material mixing amount shown in Table 1 below, and a solution obtained by dissolving an activator in 50 cc of water was added to the above aqueous solution containing a disintegrant and mixed I do. This mixture is poured into a 200 cc water dispersion of 100 g of separately prepared French method zinc flower (average specific surface area diameter: 0.3 μm), and the temperature is 60 to 90 ° C.
Then, a predetermined amount of oxide fine powder and / or silicate fine powder is added, and the mixture is stirred at the same temperature for 1 hour. After completion of the stirring, the mixture was filtered, washed with water, dried, and then heat-treated in a hydrogen, nitrogen or ammonia gas atmosphere at 200 to 900 ° C. for 30 minutes to 2 hours to obtain a conductive zinc oxide fine powder.
処理条件等を第1表に、また得られた酸化亜鉛微粉末
の比表面積径等を第2表に夫々一括して示す。Table 1 shows the treatment conditions and the like, and Table 2 shows the specific surface area and the like of the obtained zinc oxide fine powder.
尚第1表に示した各配合原料の詳細、並びに第2表に
示した比表面積等の測定法は下記の通りである。The details of each compounding raw material shown in Table 1 and the methods for measuring the specific surface area and the like shown in Table 2 are as follows.
(崩壊剤) 重炭酸アンモニウム:日産化学社製、工業用 炭酸アンモニウム:和光純薬社製、試薬1級 尿素:米山薬品社製、試薬1級 硝酸アンモニウム:米山薬品社製、試薬1級 (賦活剤) 硫酸アルミニウム:米山薬品社製、 Al2(SO4)3・18H2O 塩化アルミニウム:米山薬品社製、 AlCl3・6H2O 硝酸アンモニウム:岸田化学社製、 Al(NO3)3・9H2O (無機質微粉末) アエロジル200:日本アエロジル社製、 SiO2 比表面積200m2/g 比表面積径0.03μm アエロジルP25:日本アエロジル社製、 TiO2 比表面積50m2/g 比表面積径0.03μm アエロジルC:日本アエロジル社製、 Al2O3 比表面積100m2/g 比表面積径0.02μm ニップシールVN−3:日本シリカ社製、 SiO2 比表面積200m2/g 比表面積径0.015μm アルミナゾル−200:日産化学社製、 Al2O3として10% 平均粒径10mμ スノーテックス−O:日産化学社製、 SiO2として20% 粒径10〜20mμ ラポナイドRD:日本シリカ社製、合成ナトリウム・マグ
ネシウム・リチウム 珪酸塩(SiO2:59.5%,MgO:27.3%、 Li2O:0.8%、 Na2O:3.8%、 構造水:8.1%)、 比表面積270m2/g 比表面積径 約0.01μm (体積抵抗率) 加熱処理を終えた各試料粉末10gを、内面にテフロン
加工を施した内径25mmの内筒へ装入して100Kg/cm2に加
圧し(充填率20%)、横河電気製作所製の3223型テスタ
ーで体積抵抗率(Ωcm)を測定した。(Disintegrant) Ammonium bicarbonate: manufactured by Nissan Chemical Industries, industrial Ammonium carbonate: manufactured by Wako Pure Chemical Industries, reagent grade 1 Urea: manufactured by Yoneyama Pharmaceutical Co., Ltd., reagent grade 1 Ammonium nitrate: manufactured by Yoneyama Pharmaceutical Co., reagent grade 1 (activator ) aluminum sulfate: Yoneyama Yakuhin Ltd., Al 2 (SO 4) 3 · 18H 2 O aluminum chloride: Yoneyama Yakuhin Ltd., AlCl 3 · 6H 2 O Ammonium nitrate: Kishida chemical Co., Ltd., Al (NO 3) 3 · 9H 2 O (Inorganic fine powder) Aerosil 200: manufactured by Nippon Aerosil Co., Ltd., SiO 2 specific surface area 200 m 2 / g Specific surface area diameter 0.03 μm Aerosil P25: manufactured by Nippon Aerosil Co., Ltd., TiO 2 specific surface area 50 m 2 / g Specific surface area diameter 0.03 μm Aerosil C : Nippon Aerosil Co., Ltd., Al 2 O 3 specific surface area 100 m 2 / g Specific surface area diameter 0.02 μm Nip seal VN-3: Nippon Silica Co., Ltd., SiO 2 specific surface area 200 m 2 / g Specific surface area diameter 0.015 μm Alumina sol-200: Nissan Chemical 10% average particle size 10mμ as Al 2 O 3 Snowtex-O: manufactured by Nissan Chemical Co., Ltd., 20% as SiO 2 Particle size: 10-20 μm Raponide RD: manufactured by Nippon Silica Co., Ltd., synthetic sodium / magnesium / lithium silicate (SiO 2 : 59.5%, MgO: 27.3%, Li 2 O: 0.8%, Na 2 O: 3.8%, structured water: 8.1%), specific surface area 270m 2 / g specific surface area diameter about 0.01μm (volume resistivity) 10g of each sample powder after heat treatment, Teflon on the inner surface It was charged into a processed inner cylinder having an inner diameter of 25 mm, pressurized to 100 kg / cm 2 (filling rate: 20%), and volume resistivity (Ωcm) was measured with a 3223 type tester manufactured by Yokogawa Electric Corporation.
(比表面積径) 柴田化学機械社製の迅速面積測定装置SA−1000を用い
て各供試粉末の比表面積(Sg:m2/g)を測定し、該測定
値と供試粉末の真比重(σ:ZnOでは5.6)より次式によ
って比表面積径(d:μm)を求めた。(Specific surface area diameter) The specific surface area (Sg: m 2 / g) of each test powder was measured using a quick area measuring device SA-1000 manufactured by Shibata Chemical Machinery Co., Ltd., and the measured value and the true specific gravity of the test powder were measured. (5.6 for σ: ZnO), the specific surface area diameter (d: μm) was determined by the following equation.
(分散性) 供試粉末20gを水300cc中に投入してホモジナイザーに
より均一に分散し、これを300ccの沈降管に入れて静置
し24時間後における上方清澄部の体積(cm2)を測定
し、塗料等に配合した場合の分散性を評価した。 (Dispersibility) 20 g of the test powder was poured into 300 cc of water, uniformly dispersed by a homogenizer, placed in a 300 cc sedimentation tube, and allowed to stand. After 24 hours, the volume (cm 2 ) of the upper clarified portion was measured. Then, the dispersibility when blended in a paint or the like was evaluated.
第1,2表からも明らかである様に、本発明の規定要件
を満たす実施例(No.1〜5,8〜20)で得た導電性酸化亜
鉛粉末の比表面積径は何れも0.10μm以下であって非常
に微細なものであり、分散性も良好である。 As is clear from Tables 1 and 2, the specific surface area diameters of the conductive zinc oxide powders obtained in Examples (Nos. 1 to 5, 8 to 20) satisfying the requirements of the present invention were all 0.10 μm. The following are very fine and the dispersibility is good.
これに対し実験No.6,7は、崩壊剤や無機質微粉末の配
合量等は適正であるもの、加熱処理条件が600℃を超え
る比較例であり、加熱処理工程で微粉末同士の凝集もし
くは融着が起こり粗粒化している。また加熱処理温度が
高くなるほど粗粒化の進行は著しくなる傾向が端的に表
われている。In contrast, Experiments Nos. 6 and 7 were comparative examples in which the amount of the disintegrant or inorganic fine powder was appropriate, but the heat treatment conditions exceeded 600 ° C. Fusion occurs and the grains are coarsened. In addition, the tendency that coarsening progresses remarkably as the heat treatment temperature becomes higher clearly appears.
また実験No.21,22は凝集防止用の無機質微粉末の添加
を省略した比較例であり、何れの場合も導電性酸化亜鉛
微粉末の比表面積径は目標値の0.10μmを超えている。Experiment Nos. 21 and 22 are comparative examples in which the addition of the inorganic fine powder for preventing aggregation was omitted. In each case, the specific surface area diameter of the conductive zinc oxide fine powder exceeded the target value of 0.10 μm.
参考例 上記実験No.3で得た導電性酸化亜鉛微粉末(比表面積
径:0.024μm)と市販の導電性酸化亜鉛粉末(比表面積
径:0.3μm)を、夫々アクリル樹脂系被膜形成組成物
(三菱レーヨン社製商品名:LR−472)中に固形分換算で
40重量%となる様に添加し、ホモジサイザーで十分に混
合した後ポリエステルフィルム上に塗布した(膜厚:約
10μm)。乾燥後被膜の表面抵抗および透明性を比較し
たところ、表面抵抗は何れも108Ωcmで差は認められな
かったが、透明性については、市販品を用いたものは白
色不透明であるのに対し、実験No.3の導電性酸化亜鉛微
粉末を用いたものは透明であった。Reference Example The conductive zinc oxide fine powder (specific surface area diameter: 0.024 μm) obtained in the above Experiment No. 3 and a commercially available conductive zinc oxide powder (specific surface area diameter: 0.3 μm) were each combined with an acrylic resin film forming composition. (Mitsubishi Rayon product name: LR-472) in solid content conversion
40% by weight, mixed well with a homogenizer, and coated on a polyester film (film thickness: about
10 μm). When the surface resistance and the transparency of the coating after drying were compared, no difference was observed in the surface resistance at 10 8 Ωcm, but the transparency was white and opaque when the commercial product was used. The sample using the conductive zinc oxide fine powder of Experiment No. 3 was transparent.
[発明の効果] 本発明は以上の様に構成されており、酸化亜鉛結晶崩
壊剤の作用による微細化および酸化物微粉末および/ま
たは珪酸塩微粉末の併用と加熱処理温度の特定による凝
集防止効果の相加的乃至相乗的作用によって、比表面積
径が0.10μm以下と非常に微細で被膜に透明性を与える
ことができ、且つ分散性の優れた導電性酸化亜鉛粉末を
安価に提供し得ることになった。[Effects of the Invention] The present invention is constituted as described above, and is made fine by the action of a zinc oxide crystal disintegrant and coagulation prevention by specifying the heat treatment temperature in combination with the use of oxide fine powder and / or silicate fine powder. By the additive or synergistic effect of the effect, the specific surface area diameter can be very fine as 0.10 μm or less, which can provide transparency to the coating film, and can provide a conductive zinc oxide powder excellent in dispersibility at low cost. is what happened.
従ってこの導電性酸化亜鉛微粉末は、クリーン・ルー
ム、自動車や車輌等の窓、ブラウン管などの静電防止
膜、コンピュータをはじめとする様々の電子機器、CRT
ディスプレー等の各種タッチパネル、ELパネル、液晶セ
ル等の表面に形成される静電防止膜への導電性付与成分
として活用し得るほか、透明静電記録紙の如き様々の情
報産業記録紙や磁気テープ等の導電性付与材、電子写真
用現像材、帯電防止材、更には塗料、プラスチック、接
着剤、インキ、繊維等への導電性もしくは帯電防止性付
与成分として利用することができるほか、紫外線遮蔽効
果を活用することにより、ショーウインド用等のガラス
や透明プラスチック材中に紫外線カット材として混入し
たり、あるいは様々の樹脂成形体の表面被覆剤として使
用し樹脂自体の劣化抑制を図ることもできる。Therefore, this conductive zinc oxide fine powder can be used for clean rooms, windows of automobiles and vehicles, antistatic films such as cathode ray tubes, various electronic devices including computers, and CRTs.
It can be used as a conductivity-imparting component for the antistatic film formed on the surface of various touch panels such as displays, EL panels, and liquid crystal cells, as well as various information industry recording papers such as transparent electrostatic recording paper and magnetic tape. In addition, it can be used as a conductivity imparting material, an electrophotographic developing material, an antistatic material, and a component for imparting conductivity or antistatic property to paints, plastics, adhesives, inks, fibers, etc. By utilizing the effect, it can be mixed as a UV cut material in glass and transparent plastic materials for show windows, etc., or used as a surface coating agent for various resin molded products to suppress deterioration of the resin itself. .
Claims (7)
ルミニウム換算で0.1〜10重量部、 [III]炭酸アンモニウム、重炭酸アンモニウム、硝酸
アンモニウムおよび尿素よりなる群から選択される1種
以上の化合物:5〜100重量部 の三成分を、BET法により測定される比表面積径が0.10
μm以下である酸化物微粉末および/または珪酸塩微粉
末の存在下に水分酸系で撹拌処理し、脱水後非酸化性雰
囲気下に600℃以下の温度で加熱処理することを特徴と
する導電性酸化亜鉛微粉末の製造方法。1. [I] non-conductive zinc oxide: 100 parts by weight, [II] water-soluble or water-dispersible aluminum compound: 0.1 to 10 parts by weight in terms of aluminum oxide, [III] ammonium carbonate, ammonium bicarbonate, One or more compounds selected from the group consisting of ammonium nitrate and urea: 5 to 100 parts by weight of the three components having a specific surface area of 0.10 as measured by the BET method.
a conductive material characterized by being subjected to a stirring treatment with a water-acid system in the presence of an oxide fine powder and / or a silicate fine powder having a particle size of not more than μm, followed by heat treatment at a temperature of 600 ° C. or less in a non-oxidizing atmosphere after dehydration Method for producing fine zinc oxide powder.
ンモニウムは、アンモニアを含む水分散系に炭酸ガスを
吹込むことによって生成させたものである特許請求の範
囲第1項に記載の製造方法。2. The method according to claim 1, wherein the ammonium carbonate and / or ammonium bicarbonate is produced by blowing carbon dioxide gas into an aqueous dispersion containing ammonia.
温度で行なう特許請求の範囲第1項または第2項に記載
の製造方法。3. The method according to claim 1, wherein the diffusion treatment in the aqueous dispersion system is performed at a temperature from room temperature to 100 ° C.
ハロゲン化物、水酸化物、硫酸塩、硝酸塩よりなる群か
ら選択される1種以上である特許請求の範囲第1項〜第
3項のいずれかに記載の製造方法。4. The method according to claim 1, wherein the aluminum compound is formate, acetate,
The method according to any one of claims 1 to 3, wherein the method is at least one selected from the group consisting of halides, hydroxides, sulfates, and nitrates.
が、シリカ、アルミナ、チタニアおよび珪酸塩類から選
択された1種以上の微粉末である特許請求の範囲第1項
〜第4項のいずれかに記載の製造方法。5. The method according to claim 1, wherein said oxide fine powder and / or silicate fine powder is at least one fine powder selected from silica, alumina, titania and silicates. The production method according to any one of the above.
を酸化亜鉛100重量部に対し0.05〜10重量部存在させる
特許請求の範囲第1項〜第5項のいずれかに記載の製造
方法。6. The method according to claim 1, wherein the oxide fine powder and / or the silicate fine powder is present in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of zinc oxide. .
雰囲気下で行なう特許請求の範囲第1項〜第6項のいず
れかに記載の製造方法。7. The production method according to claim 1, wherein the heat treatment is performed in an atmosphere of nitrogen, ammonia or hydrogen.
Priority Applications (1)
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JP62284636A JP2583536B2 (en) | 1987-11-11 | 1987-11-11 | Method for producing conductive zinc oxide fine powder |
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JP62284636A JP2583536B2 (en) | 1987-11-11 | 1987-11-11 | Method for producing conductive zinc oxide fine powder |
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EP1398673A3 (en) | 2002-09-12 | 2005-08-31 | Canon Kabushiki Kaisha | Developer |
JP5010182B2 (en) * | 2005-06-02 | 2012-08-29 | 株式会社 資生堂 | Disintegrating zinc oxide powder, method for producing the same, and cosmetics containing the same |
JP5010183B2 (en) * | 2005-06-02 | 2012-08-29 | 株式会社 資生堂 | Method for producing disintegrating zinc oxide powder |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54161598A (en) * | 1978-06-12 | 1979-12-21 | Honshu Kemikaru Kk | Manufacture of electrically conductive zinc oxide |
JPS6186421A (en) * | 1984-10-05 | 1986-05-01 | Sumitomo Alum Smelt Co Ltd | Preparation of white electroconductive powder |
-
1987
- 1987-11-11 JP JP62284636A patent/JP2583536B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
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JPH01126228A (en) | 1989-05-18 |
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