JP4749733B2 - Hydrophobic magnetic iron oxide particles - Google Patents
Hydrophobic magnetic iron oxide particles Download PDFInfo
- Publication number
- JP4749733B2 JP4749733B2 JP2005039145A JP2005039145A JP4749733B2 JP 4749733 B2 JP4749733 B2 JP 4749733B2 JP 2005039145 A JP2005039145 A JP 2005039145A JP 2005039145 A JP2005039145 A JP 2005039145A JP 4749733 B2 JP4749733 B2 JP 4749733B2
- Authority
- JP
- Japan
- Prior art keywords
- iron oxide
- magnetic iron
- particles
- silane compound
- oxide particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Description
本発明は磁性酸化鉄粒子、好ましくはＳｉとＰを含有する磁性酸化鉄の表面に、特定のシラン化合物を所定量均一に被覆させることにより、環境特性ならびに溶媒中での分散安定性に優れ、かつシャープな粒度分布を示し、さらに残留磁化が低く、かつ飽和磁化が高く、特に重合法トナー用をはじめとする静電複写磁性トナー用磁性粉として好適な疎水性磁性酸化鉄粒子に関する。 The present invention is excellent in environmental characteristics and dispersion stability in a solvent by uniformly coating a specific amount of a specific silane compound on the surface of magnetic iron oxide particles, preferably magnetic iron oxide containing Si and P. The present invention also relates to hydrophobic magnetic iron oxide particles which exhibit a sharp particle size distribution, have a low residual magnetization and a high saturation magnetization, and are particularly suitable as magnetic powders for electrostatic copying magnetic toners including those for polymerization toners.
プリンターや電子複写機等の磁性一成分トナー用材料として、磁性体粒子が広く利用されており、磁性体粒子としては磁性酸化鉄粒子が多く使用されている。磁性一成分トナーとしては各種の基本的現像特性が要求されるが、近年、特にデジタル技術を用いたプリンターや複写機の急速な発達により、市場はより高度な特性を要求するようになってきた。この要求を満足するためには、マシン特性の向上は当然のことであるが、これに追従出来る高い特性を有するトナーの開発が不可欠となってきた。 Magnetic particles are widely used as materials for magnetic one-component toners such as printers and electronic copying machines, and magnetic iron oxide particles are often used as magnetic particles. Various basic development characteristics are required for magnetic one-component toners, but in recent years, with the rapid development of printers and copiers using digital technology in particular, the market has demanded more advanced characteristics. . In order to satisfy this requirement, it is natural to improve the machine characteristics, but it has become indispensable to develop a toner having high characteristics capable of following this.
現在のところ磁性一成分トナーの主流は、乾式プロセスで作製する粉砕法トナーであるが、粉砕するという製法のため避けられない幾つかの欠点がある。
例えば、特開２００３−１３１４２２号公報（特許文献１）には以下のように記載されている。
At present, the mainstream of magnetic one-component toner is a pulverized toner manufactured by a dry process, but there are some disadvantages that cannot be avoided due to the manufacturing method of pulverizing.
For example, it describes as follows in Unexamined-Japanese-Patent No. 2003-131422 (patent document 1).
粉砕法トナーでは、トナー表面へ樹脂に比して相対的に抵抗の低い磁性体の露出が避けられないため、トナー帯電性能の低下やトナー流動性の低下が見られ、その上、長期間の使用においては、トナー同士あるいは規制部材との摺擦による磁性体の剥離に伴う画像濃度の低下やスリーブゴーストと呼ばれる濃淡のムラの発生などトナーの劣化などが引き起こす問題がある。 In the pulverized toner, it is inevitable that the magnetic surface having a relatively low resistance compared to the resin is exposed to the toner surface, so that the toner charging performance and the toner fluidity are deteriorated. In use, there is a problem that the toner is deteriorated such as a decrease in image density due to peeling of the magnetic material due to rubbing between the toners or the regulating member, or generation of unevenness of density called sleeve ghost.
また、粉砕法では、磁性粉あるいは着色剤等の固体微粒子を樹脂中へ完全に均一に分散することは困難であり、その分散の度合によっては、かぶりの増大、画像濃度の低下の原因となる。さらに、粉砕法は、前述したようにトナーの表面に磁性酸化鉄粒子が露出してしまうため、トナーの流動性や過酷環境下での帯電安定性にどうしても問題が残る。 Also, in the pulverization method, it is difficult to completely disperse solid fine particles such as magnetic powder or colorant in the resin, and depending on the degree of dispersion, it may cause an increase in fog and a decrease in image density. . Furthermore, as described above, the pulverization method exposes the magnetic iron oxide particles to the surface of the toner, so that problems still remain with respect to the fluidity of the toner and the charging stability under harsh environments.
すなわち、粉砕法においては、高精細・高画質化で要求されるトナーの微粒子化に限界があり、それに伴い粉体特性、特にトナーの均一帯電性および流動性が著しく減衰する。
以上の様な粉砕法によるトナーの問題点を克服するため、更には上記のごとき要求を満たすため、懸濁重合法トナーを始めとする、湿式プロセスで製造する各種重合法の開発が盛んである。
That is, in the pulverization method, there is a limit to finer toner particles required for high definition and high image quality, and accordingly, powder characteristics, particularly toner uniform chargeability and fluidity, are significantly attenuated.
In order to overcome the problems of the toner by the pulverization method as described above, and to satisfy the above-described requirements, various polymerization methods manufactured by a wet process such as suspension polymerization toner are actively developed. .
湿式プロセスによる製造方法では、粉砕工程が全く含まれないために、トナーに脆性が必要でなく、樹脂として軟質の材料を使用することができ、トナーの微粒子化が容易に可能であることから、得られるトナーの粒度分布が比較的シャープで分級工程を省略することができ、または分級したとしても、高収率でトナーが得られる。 In the manufacturing method by the wet process, since the pulverization step is not included at all, the toner does not need to be brittle, a soft material can be used as the resin, and the toner can be easily made into fine particles. The particle size distribution of the toner obtained is relatively sharp and the classification step can be omitted, or even if classification is performed, the toner can be obtained in high yield.
更には、得られるトナーの形状が球状であることから流動性に優れ、高画質化に有利となる。
このような重合法トナーは湿式プロセスで製造されるものであり、トナーに用いる磁性酸化鉄粒子も自ずと粉砕法トナーに適用するものとは異なる特性が要求される。
Furthermore, since the obtained toner has a spherical shape, it has excellent fluidity and is advantageous for high image quality.
Such a polymerized toner is manufactured by a wet process, and the magnetic iron oxide particles used for the toner are required to have characteristics different from those applied to the pulverized toner.
例えば重合法トナーの製造方法において、表面が親水性である磁性酸化鉄粒子を用いた場合、トナーの帯電特性および画像特性は著しく低下する。これは、磁性酸化鉄の表面が親水性のため非水系溶媒中では十分に分散出来ずに、トナー中での磁性酸化鉄の分散性が著しく劣る結果となるためである。また、水系分散媒中に磁性酸化鉄粒子が移行し易くなるので、結果として、トナー表面に磁性酸化鉄粒子が露出し、本来重合法トナーが目標とする所望の特性は得られ難い。 For example, when magnetic iron oxide particles having a hydrophilic surface are used in a method for producing a polymerization toner, the charging characteristics and image characteristics of the toner are significantly lowered. This is because the surface of the magnetic iron oxide is hydrophilic and cannot be sufficiently dispersed in a non-aqueous solvent, resulting in extremely poor dispersibility of the magnetic iron oxide in the toner. Further, since the magnetic iron oxide particles are easily transferred into the aqueous dispersion medium, as a result, the magnetic iron oxide particles are exposed on the surface of the toner, and it is difficult to obtain desired characteristics originally intended for the polymerization toner.
すなわち、重合法トナーにおいて重要なことは、磁性酸化鉄粒子を分散させるために分散溶媒と磁性酸化鉄粒子の親和性を高めることであるが、機械的分散力に頼るのは限界がある。従って、磁性酸化鉄粉末の有する各種溶媒中での分散性や分散安定性のレベルをいかにして向上させるかが、最終的なトナー中での分散状態を改善するための課題である。 That is, what is important in the polymerization toner is to increase the affinity between the dispersion solvent and the magnetic iron oxide particles in order to disperse the magnetic iron oxide particles, but there is a limit to relying on the mechanical dispersion force. Therefore, how to improve the level of dispersibility and dispersion stability of the magnetic iron oxide powder in various solvents is a problem for improving the final dispersion state in the toner.
そのための手法として、重合法トナーの製造に用いる分散媒に適するよう、使用する磁性酸化鉄の表面を改質することがあげられ、これまで種々の検討がなされてきた。
例えば、特開昭５９−２００２５４号公報（特許文献２）、特開昭５９−２００２５６号公報（特許文献３）、特開昭５９−２００２５７号公報（特許文献４）、特開昭５９−２２４１０２号公報（特許文献５）等に磁性体の各種シランカップリング剤処理技術が提案されており、特開昭６３−２５０６６０号公報（特許文献６）、特開平１０−２３９８９７号公報（特許文献７）では、ケイ素元素含有磁性粒子をシランカップリング剤で処理する技術が開示されている。
For this purpose, the surface of the magnetic iron oxide to be used is modified so as to be suitable for the dispersion medium used in the production of the polymerization method toner, and various studies have been made so far.
For example, Japanese Patent Application Laid-Open No. 59-200244 (Patent Document 2), Japanese Patent Application Laid-Open No. 59-200266 (Patent Document 3), Japanese Patent Application Laid-Open No. 59-200237 (Patent Document 4), Japanese Patent Application Laid-Open No. 59-224102. Patent Document 5 (Patent Document 5) and the like have proposed various silane coupling agent treatment techniques for magnetic materials, such as JP-A 63-250660 (Patent Document 6) and JP-A 10-239897 (Patent Document 7). ) Discloses a technique for treating silicon element-containing magnetic particles with a silane coupling agent.
しかしながら、これらの処理により磁性酸化鉄粒子の表面は撥水性となり、トナー中の分散性はある程度向上するものの、表面処理の均一性は必ずしも達成されていないので、粒子同士の合一や疎水化されていない粒子の発生を避けることができず、トナー中の分散性を良好なレベルにまで向上させるには不十分である。 However, these treatments make the surface of the magnetic iron oxide particles water-repellent and the dispersibility in the toner is improved to some extent, but the uniformity of the surface treatment is not necessarily achieved, so the particles are united or made hydrophobic. The generation of particles that cannot be avoided cannot be avoided and is insufficient to improve the dispersibility in the toner to a good level.
また、磁性一成分トナーの場合は重合法トナーにおいても、トナー中のかなりの部分を磁性体粒子が占めるため、磁気特性が重要であることは言うまでもない。
磁性酸化鉄の磁気特性については、飽和磁化はできるだけ高く、その一方で、磁気凝集に影響する残留磁化はできるだけ小さいものが好ましい。しかしながら、磁性酸化鉄、特に強磁性体の残留磁化と飽和磁化は通常連動しており、飽和磁化が大きくなると残留磁化も大きくなるという性質のため、これを満足するものはなかった。
In the case of a magnetic one-component toner, it is needless to say that the magnetic properties are important because the magnetic particles occupy a considerable portion of the toner even in the polymerization toner.
Regarding the magnetic properties of magnetic iron oxide, it is preferable that the saturation magnetization is as high as possible, while the remanent magnetization that affects magnetic aggregation is as small as possible. However, the remanent magnetization and saturation magnetization of magnetic iron oxide, particularly ferromagnetic materials, are usually linked, and there is nothing that satisfies this because the remanent magnetization increases as the saturation magnetization increases.
例えば、特開昭６３−１２８３５６号公報（特許文献８）において、７９．６ｋＡ／ｍでの飽和磁化が６５〜１２０Ａｍ２／ｋｇであり、粒子の最長寸法と最短寸法の比が１．０〜１．５の球状磁性酸化鉄が開示されているが、残留磁化についての概念は記載されていない。 For example, in JP-A-63-128356 (Patent Document 8), the saturation magnetization at 79.6 kA / m is 65 to 120 Am 2 / kg, and the ratio of the longest dimension to the shortest dimension of the particles is 1.0 to Although 1.5 spherical magnetic iron oxide is disclosed, the concept of remanent magnetization is not described.
また、特開２００２−３２８４９３号公報（特許文献９）及び特開２００３−４３７５６号公報（特許文献１０）においては、シランカップリング剤処理をしたＭｇ、Ｓｉ、Ｍｎ、Ｐの少なくとも１種を含む磁性酸化鉄が開示されているが、キャリアとしての飽和磁化と残留磁化の値しか記載されていない。 In addition, JP-A-2002-328493 (Patent Document 9) and JP-A-2003-43756 (Patent Document 10) include at least one of Mg, Si, Mn, and P treated with a silane coupling agent. Magnetic iron oxide is disclosed, but only values of saturation magnetization and residual magnetization as carriers are described.
また、特開平１０−１０１３３９号公報（特許文献１１）では、Ｆｅに対し０．１〜５．０重量％のＰ、Ｆｅに対し０．１〜５．０重量％のＡｌ、及び、Ｆｅに対し５．０重量％以下のＳｉを含有し、残留磁化(Ａｍ２／ｋｇ)／比表面積(ｍ２／ｇ)が０．９以下であることを特徴とする磁性酸化鉄粒子粉末が記載されているが、残留磁化は５．９〜７．５Ａｍ２／ｋｇと高いものである。
本発明はこれら従来技術の課題を解決すべくなされたもので、各種非水系溶媒中での分散性に優れ、非水系溶媒中へのシラン化合物の溶出を適正範囲にすることにより、分散安定性が良く、これによりトナーの製造安定性に優れ、残留磁化が低くかつ飽和磁化が高い磁性酸化鉄粒子を提供することを目的としている。 The present invention has been made to solve these problems of the prior art, and is excellent in dispersibility in various non-aqueous solvents, and by making the elution of the silane compound into the non-aqueous solvent within an appropriate range, the dispersion stability is improved. Accordingly, an object of the present invention is to provide magnetic iron oxide particles having excellent toner production stability, low residual magnetization, and high saturation magnetization.
すなわち、本発明は、磁性酸化鉄を基体粒子とし、その表面にシラン化合物を被覆した疎水性磁性酸化鉄粒子であって、シラン化合物のトルエン中への溶出率が３０％以下であることを特徴とする疎水性磁性酸化鉄粒子である。 That is, the present invention is a hydrophobic magnetic iron oxide particle having magnetic iron oxide as a base particle and coated on its surface with a silane compound, wherein the elution rate of the silane compound into toluene is 30% or less. These are hydrophobic magnetic iron oxide particles.
本発明の疎水性磁性酸化鉄粒子においては、トルエン中でのシラン化合物の溶出率が３０％以下であることが重要である。本発明におけるシラン化合物のトルエン中への溶出率は後述する方法により測定されたものである。 In the hydrophobic magnetic iron oxide particles of the present invention, it is important that the elution rate of the silane compound in toluene is 30% or less. The elution rate of the silane compound in toluene in the present invention is measured by the method described later.
懸濁重合法トナーの製造に用いる非水系溶媒は、シラン化合物に対して良溶媒のものが多く、つまりは磁性酸化鉄粒子に被覆したシラン化合物もその被覆状態によっては溶出してしまうことがある。 Non-aqueous solvents used for the production of suspension polymerization toners are often good solvents for silane compounds, that is, silane compounds coated on magnetic iron oxide particles may be eluted depending on the coating state. .
一般的にシラン化合物は、磁性酸化鉄粒子表面に存在する水酸基と水素結合した後、脱水反応して、化学的に結合するといわれている。しかし、これはあくまでも磁性酸化鉄粒子上に均一に、しかも適正な量を被覆させたときのことであり、シラン化合物が磁性酸化鉄粒子の表面水酸基と水素結合する前に、例えば、シラン化合物同士が縮合して、１つの粒子のように振る舞った場合には、このものは化学的にではなく物理的に磁性酸化鉄粒子表面に吸着するようになる。物理的に吸着したもののほとんどは本来の疎水化処理するという目的に対しては無駄なものであり、できるだけ少ない方が好ましい。 In general, it is said that the silane compound is chemically bonded by dehydration after hydrogen bonding with a hydroxyl group present on the surface of the magnetic iron oxide particles. However, this is only when the magnetic iron oxide particles are coated uniformly and in an appropriate amount. Before the silane compound hydrogen bonds with the surface hydroxyl groups of the magnetic iron oxide particles, for example, When they condense and behave like a single particle, they are physically adsorbed on the surface of the magnetic iron oxide particles rather than chemically. Most of the physically adsorbed materials are useless for the purpose of the original hydrophobization treatment, and it is preferable that the amount is as small as possible.
すなわち、疎水化処理において重要なことは、いかに物理的に吸着した成分を少なくするかということにある。物理吸着成分のすべてが問題となるわけではなく、物理吸着成分が存在することによりみかけの疎水化度は、むしろ高くなる傾向を示すこともある。しかし、特に懸濁重合法トナー用の疎水性磁性酸化鉄粒子のように、疎水化処理剤にとって良溶媒となる分散媒中に懸濁させるような場合には、物理吸着成分の存在は悪影響を及ぼす場合が多い。物理吸着成分が多いとみかけ上疎水化度は高く、樹脂中への初期の分散性は良好で疎水化処理が均一になっているように見えても、時間の経過とともに非水系分散媒中で物理吸着成分が脱離して親水性表面があらわれ、磁性酸化鉄粒子同士が凝集する。その結果、個々のトナーにおける磁性酸化鉄の分散性が悪くなる。 That is, what is important in the hydrophobization treatment is how to reduce the amount of physically adsorbed components. Not all of the physical adsorption components become a problem, and the presence of the physical adsorption components may tend to increase the apparent degree of hydrophobicity. However, the presence of a physical adsorption component has an adverse effect when suspended in a dispersion medium that is a good solvent for the hydrophobic treatment agent, such as hydrophobic magnetic iron oxide particles for suspension polymerization toners. In many cases. Apparently, the degree of hydrophobization is high when there are many physisorbed components, the initial dispersibility in the resin is good and the hydrophobizing treatment seems to be uniform, but in a non-aqueous dispersion medium over time The physical adsorption component is desorbed and a hydrophilic surface appears, and the magnetic iron oxide particles are aggregated. As a result, the dispersibility of the magnetic iron oxide in each toner is deteriorated.
本発明者らが鋭意研究を行った結果、シラン化合物を被覆した磁性酸化鉄粒子におけるシラン化合物のトルエン中への溶出率を３０％以下、望ましくは３〜３０％、さらに望ましくは３〜２０％とすることがよいことがわかった。 As a result of intensive studies by the present inventors, the elution rate of the silane compound into toluene in the magnetic iron oxide particles coated with the silane compound is 30% or less, desirably 3 to 30%, more desirably 3 to 20%. It turned out to be good.
トルエン中に溶出した成分は、化学的に結合した状態でなく、物理的に吸着した成分に相当すると考えられる。
前記のシラン化合物は、ＲａＳｉＸ４−ａ(Ｒ；炭素数４以上１８以下のアルキル基，ａ；１〜３の整数，Ｘ；メトキシ基またはエトキシ基)で表されるシラン化合物が好ましい。
The component eluted in toluene is considered not to be in a chemically bound state but to correspond to a physically adsorbed component.
The silane compound is preferably a silane compound represented by RaSiX 4-a (R: an alkyl group having 4 to 18 carbon atoms, a: an integer of 1 to 3, X: a methoxy group or an ethoxy group).
上式で表されるシラン化合物が適量被覆されていれば、磁性酸化鉄の疎水性は十分であり、磁性酸化鉄粒子同士の合一も極めて少なくなるため粒度分布が狭く、十分に分散性を持たせることができる。 If an appropriate amount of the silane compound represented by the above formula is coated, the hydrophobicity of the magnetic iron oxide is sufficient, and the coalescence between the magnetic iron oxide particles is extremely small, so the particle size distribution is narrow and the dispersibility is sufficient. You can have it.
前記シラン化合物は具体的には、ｎ−ブチルトリメトキシシラン、ｎ−ヘキシルトリメトキシシラン、フェニルトリエトキシシラン、ｎ−オクチルトリエトキシシラン、ｎ−オクチルトリメトキシシラン、ｎ−デシルトリメトキシシラン、ジフェニルジメトキシシラン、ｎ−ヘキサデシルトリメトキシシラン、ｎ−オクタデシルトリメトキシシラン等を挙げることができ、前処理を施せばクロロシラン系の化合物の使用も可能である。 Specifically, the silane compound is n-butyltrimethoxysilane, n-hexyltrimethoxysilane, phenyltriethoxysilane, n-octyltriethoxysilane, n-octyltrimethoxysilane, n-decyltrimethoxysilane, diphenyl. Examples include dimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, and the like. If pretreatment is performed, a chlorosilane-based compound can also be used.
前記シラン化合物の被覆量は、前記基体粒子の単位表面積当たり１．０〜２．５ｍｇ／ｍ２であることが好ましく、さらに１．５〜２．０ｍｇ／ｍ２であればより好ましい。この範囲であれば前記シラン化合物が粒子全体を覆い、樹脂とのなじみが良好となる。 The coating amount of the silane compound is preferably 1.0 to 2.5 mg / m 2 per unit surface area of the base particles, and more preferably 1.5 to 2.0 mg / m 2 . If it is this range, the said silane compound will cover the whole particle | grain and a familiarity with resin will become favorable.
本発明の疎水性磁性酸化鉄粒子の疎水化度は６０％〜８５％、水分量が０．１５重量％以下であって、高温高湿下（３０℃、相対湿度８１％）で吸着水分量が０．０５重量％以下であることが好ましい。本発明における疎水化度とは後述するメタノール滴定試験により測定されたものである。 The hydrophobic magnetic iron oxide particles of the present invention have a hydrophobization degree of 60% to 85%, a water content of 0.15% by weight or less, and an adsorbed water content at high temperature and high humidity (30 ° C., relative humidity 81%). Is preferably 0.05% by weight or less. The degree of hydrophobicity in the present invention is measured by a methanol titration test described later.
疎水化度が前記範囲であれば、懸濁重合法において、造粒中に磁性酸化鉄が水系に移行したり、磁性酸化鉄がトナー表面に露出したり、トナーから遊離して存在することはない。また、樹脂モノマー中での分散性も優れたもののとなる。 If the degree of hydrophobicity is in the above range, in the suspension polymerization method, the magnetic iron oxide is transferred to an aqueous system during granulation, the magnetic iron oxide is exposed on the toner surface, or is present free from the toner. Absent. Further, the dispersibility in the resin monomer is excellent.
疎水化度が６０％〜８５％であることに加え、水分量が０．１５重量％以下で、高温高湿下での吸着水分量が０．０５％以下であれば磁性酸化鉄粒子表面の親水性が低いので樹脂中での分散性が良好となる。 In addition to the hydrophobization degree being 60% to 85%, if the moisture content is 0.15% by weight or less and the adsorption moisture content under high temperature and high humidity is 0.05% or less, the surface of the magnetic iron oxide particles Since the hydrophilicity is low, the dispersibility in the resin is good.
また、本発明の疎水性磁性酸化鉄粒子においては、スチレン・ｎブチルアクリレート分散媒中での粒度分布において、体積基準における累積平均粒子径（ｄ５０％）が０．５〜１．５μｍであり、かつ、次式： Moreover, in the hydrophobic magnetic iron oxide particles of the present invention, in the particle size distribution in the styrene / n-butyl acrylate dispersion medium, the cumulative average particle size (d50%) on a volume basis is 0.5 to 1.5 μm, And the following formula:
で示されるＳＤ値が０．５μｍ以下であることが好ましく、０．４μm以下であればさらに好ましい(なお、ｄ５０％とは粒子径の累積カーブが５０％となる点の粒子径を示し、ｄ８４％とは粒子径の累積カーブが８４％となる点の粒子径を示し、ｄ１６％とは粒子径の累積カーブが１６％となる点の粒子径を示す)。 Is preferably 0.5 μm or less, and more preferably 0.4 μm or less (where d50% indicates the particle diameter at which the cumulative particle diameter curve is 50%, d84 % Indicates the particle diameter at a point where the cumulative curve of particle diameter is 84%, and d16% indicates the particle diameter at the point where the cumulative curve of particle diameter becomes 16%).
前記の平均粒子径及びＳＤ値の範囲であれば、樹脂中での分散性は良好であり、トナーの色相においても問題がない。
次に本発明の疎水性磁性酸化鉄の基体粒子となる磁性酸化鉄は、マグネタイト、マグヘマイト等であり、これらを１種または２種以上併用して用いる。その粒子形状は多面体、八面体、六面体、球形、針状、鱗片状などその形状は限定されないが、比較的残留磁化が低く、磁気凝集が小さいことに起因して、粒子同士の絡みが少なく、分散性に優れた球状であることが好ましい。また、リン、アルミニウム、珪素、コバルト、ニッケル、銅、マグネシウム、マンガン等の元素を含んでもよい。また、これらの磁性酸化鉄は、窒素吸着法によるＢＥＴ比表面積が２〜５０ｍ２／ｇが好ましく、５〜３０ｍ２／ｇが特に好ましい。
When the average particle diameter and SD value are within the above ranges, the dispersibility in the resin is good, and there is no problem in the hue of the toner.
Next, the magnetic iron oxide used as the base particle of the hydrophobic magnetic iron oxide of the present invention is magnetite, maghemite or the like, and these are used alone or in combination of two or more. The shape of the particle is not limited, such as polyhedron, octahedron, hexahedron, sphere, needle shape, scale shape, etc., but relatively low remanence, due to small magnetic aggregation, less entanglement between particles, A spherical shape excellent in dispersibility is preferred. Further, elements such as phosphorus, aluminum, silicon, cobalt, nickel, copper, magnesium, manganese may be included. In addition, these magnetic iron oxides preferably have a BET specific surface area of 2 to 50 m 2 / g, particularly preferably 5 to 30 m 2 / g by a nitrogen adsorption method.
本発明の磁性酸化鉄粒子においては、ＴＥＭ観察による一次粒子の体積基準における累積平均粒子径が０．０５〜０．５μｍが好ましく、０．１〜０．４μｍがより好ましく、０．２〜０．３μｍが特に好ましい。前記のＢＥＴ比表面積及び体積平均粒子径は着色力や分散安定性を考慮した場合の好適な範囲である。 In the magnetic iron oxide particles of the present invention, the cumulative average particle diameter on the volume basis of primary particles by TEM observation is preferably 0.05 to 0.5 μm, more preferably 0.1 to 0.4 μm, and more preferably 0.2 to 0 .3 μm is particularly preferred. The BET specific surface area and the volume average particle diameter are suitable ranges in consideration of coloring power and dispersion stability.
本発明の疎水性磁性酸化鉄粒子は、前記基体粒子が、ＰをＰ２Ｏ５換算で０．１５〜０．５重量％、ＳｉをＳｉＯ２換算で０．７〜２．０重量％含有する球状マグネタイト粒子であって、印加磁場７９．６ｋＡ／ｍの飽和磁化が６７Ａｍ２／ｋｇ以上、残留磁化が４Ａｍ２／ｋｇ以下であることが好ましく、飽和磁化が６９Ａｍ２／ｋｇ以上、残留磁化が４Ａｍ２／ｋｇ以下であればさらに好ましい。Ｐ及びＳｉに関してはＰをＰ２Ｏ５換算で０．３〜０．４重量％、ＳｉをＳｉＯ２換算で０．９〜１．５重量％を球状マグネタイト粒子に含有させるのが特に好ましい。この場合、当該マグネタイトの体積基準における累積平均粒子径は０．２〜０．３μｍが好ましい。 Hydrophobic magnetic iron oxide particles of the present invention, the substrate particles is from 0.15 to 0.5 wt% of P in terms of P 2 O 5, 0.7 to 2.0 wt% content of Si in terms of SiO 2 Spherical magnetite particles having an applied magnetic field of 79.6 kA / m and preferably a saturation magnetization of 67 Am 2 / kg or more, a residual magnetization of 4 Am 2 / kg or less, a saturation magnetization of 69 Am 2 / kg or more, and a residual magnetization Is more preferably 4 Am 2 / kg or less. With respect to P and Si, it is particularly preferable that spherical magnetite particles contain P in an amount of 0.3 to 0.4 wt% in terms of P 2 O 5 and Si in an amount of 0.9 to 1.5 wt% in terms of SiO 2 . In this case, the cumulative average particle diameter on the volume basis of the magnetite is preferably 0.2 to 0.3 μm.
Ｓｉのみの場合は、マグネタイト粒子は球状を呈するものの前記の磁気特性は有さない。また、Ｐのみの場合は、マグネタイト粒子の粒度分布が悪くなるため、結果として所望の磁気特性が得られ難い。すなわちＳｉとＰを併用することが重要である。ただし、Ｐ及びＳｉの含有量が前記の範囲を下回ると所望の磁気特性とはなり難く、また、前記の範囲を超えると粒度分布が悪くなるので好ましくない。特にＳｉ添加量がＳｉＯ２換算で２．０重量％を超えると、マグネタイト粒子表面から露出するＳｉ量が多くなり、シラン化合物の被覆に悪影響を及ぼすので好ましくない。 In the case of Si alone, although the magnetite particles are spherical, they do not have the above magnetic properties. Further, in the case of P alone, the particle size distribution of the magnetite particles is deteriorated, and as a result, it is difficult to obtain desired magnetic characteristics. That is, it is important to use Si and P together. However, if the content of P and Si is below the above range, the desired magnetic properties are hardly obtained, and if it exceeds the above range, the particle size distribution is deteriorated, which is not preferable. In particular, if the amount of Si added exceeds 2.0% by weight in terms of SiO 2 , the amount of Si exposed from the surface of the magnetite particles increases, which adversely affects the coating of the silane compound.
本発明における磁性酸化鉄粒子が飽和磁束密度が高く、かつ残留磁束密度が低くなる理由については未だ明らかではないが、Ｐ及びＳｉの含有量を前記の範囲に設定することで、マグネタイト粒子中の磁壁の移動に何らかの作用を及ぼすためではないかと考えている。 The reason why the magnetic iron oxide particles in the present invention have a high saturation magnetic flux density and a low residual magnetic flux density is not yet clear, but by setting the P and Si contents in the above ranges, I think that it may have some effect on the movement of the domain wall.
本発明の疎水性磁性酸化鉄粒子は代表的には以下の方法で製造される。まず基体となる磁性酸化鉄粒子の製造法を湿式法のマグネタイトを例にとって説明する。
湿式法のマグネタイト粒子は基本的に第一鉄塩水溶液と水酸化アルカリとの中和反応することにより水酸化第一鉄沈殿を生成させ、必要によっては水酸化第一鉄沈殿の生成前、生成中もしくは生成後にＳｉ、Ａｌ、Ｐ、Ｍｇ等の成分を添加し、ｐＨ、温度および空気吹き込み量を調整しながら酸化反応を進めることによりマグネタイト粒子が得られる。第一鉄塩水溶液と水酸化アルカリとの比率、ｐＨ、酸化速度、鉄濃度、添加成分の種類や量によって、得られるマグネタイト粒子の大きさや形状を任意に調整することができる。得られる形状は多面体、八面体、六面体、球形、針状、鱗片状などであり、大きさは実用的には体積基準における一次の累積平均粒子径が０．０５〜０．５μｍのものが好ましい。
The hydrophobic magnetic iron oxide particles of the present invention are typically produced by the following method. First, a method for producing magnetic iron oxide particles as a substrate will be described by taking a wet magnetite as an example.
Wet method magnetite particles basically generate ferrous hydroxide precipitates by neutralizing the ferrous salt aqueous solution and alkali hydroxide, and if necessary, before the formation of ferrous hydroxide precipitates Magnetite particles can be obtained by adding components such as Si, Al, P, Mg, etc., during or after production, and advancing the oxidation reaction while adjusting the pH, temperature and air blowing amount. The size and shape of the obtained magnetite particles can be arbitrarily adjusted according to the ratio of ferrous salt aqueous solution and alkali hydroxide, pH, oxidation rate, iron concentration, and type and amount of the added component. The obtained shape is a polyhedron, octahedron, hexahedron, sphere, needle, scale, etc., and the size is practically preferably a primary cumulative average particle size on a volume basis of 0.05 to 0.5 μm. .
第一鉄塩水溶液としては、硫酸第一鉄、塩化第一鉄、硝酸第一鉄等があげられるが、一般的に硫酸法酸化チタン製造時に副生する硫酸鉄、鋼板の表面洗浄に伴って副生する硫酸鉄を使用する。また、水酸化アルカリとしては、水酸化ナトリウム、水酸化カリウム、水酸化カルシウム等のアルカリ金属、アルカリ土類金属の水酸化物並びに水酸化アンモニウム、アンモニアガス等を用いることができる。 Examples of ferrous salt aqueous solutions include ferrous sulfate, ferrous chloride, ferrous nitrate, etc., but generally, iron sulfate by-produced during the production of sulfuric acid method titanium oxide, along with the surface cleaning of steel sheets Use by-product iron sulfate. Examples of the alkali hydroxide include alkali metals such as sodium hydroxide, potassium hydroxide, and calcium hydroxide, hydroxides of alkaline earth metals, ammonium hydroxide, ammonia gas, and the like.
本発明の疎水性磁性酸化鉄粒子において、その磁気特性を飽和磁化を高く、かつ残留磁化を低くしたもの、具体的には、印加磁場７９．６ｋＡ／ｍにおける飽和磁化σｓを６７Ａｍ２／ｋｇ以上、残留磁化σｒを４Ａｍ２／ｋｇ以下とするためには、基体粒子に、ＰをＰ２Ｏ５換算で０．１５〜０．５重量％、ＳｉをＳｉＯ２換算で０．７〜２．０重量％含有した球状マグネタイト粒子を以下の条件で製造する。 In the hydrophobic magnetic iron oxide particles of the present invention, the magnetic properties of which the saturation magnetization is high and the residual magnetization is low, specifically, the saturation magnetization σs at an applied magnetic field of 79.6 kA / m is 67 Am 2 / kg or more. In order to set the residual magnetization σr to 4 Am 2 / kg or less, P is 0.15 to 0.5% by weight in terms of P 2 O 5 and Si is 0.7 to 2 . Spherical magnetite particles containing 0% by weight are produced under the following conditions.
まず、第一鉄塩水溶液と水酸化アルカリとの中和反応することにより水酸化第一鉄沈殿を生成させるが、第一鉄塩に対する水酸化アルカリの量は第一鉄塩水溶液中のＦｅ２＋に対し、０．９〜１．０当量であることが好ましい。０．９当量未満では球状粒子の生成率が低くなり、ゲーサイトが副生してくるので好ましくない。また、１．０当量を超えると立方体、八面体、多面体が生成し易い領域となり、球状マグネタイト粒子は得られ難い。 First, a ferrous hydroxide precipitate is generated by a neutralization reaction between an aqueous ferrous salt solution and an alkali hydroxide, and the amount of alkali hydroxide relative to the ferrous salt is Fe 2+ in the aqueous ferrous salt solution. It is preferable that it is 0.9-1.0 equivalent with respect to. If it is less than 0.9 equivalent, the production rate of spherical particles is low, and goethite is by-produced, which is not preferable. Moreover, when it exceeds 1.0 equivalent, it will become an area | region where a cube, an octahedron, and a polyhedron are easy to produce | generate, and it is difficult to obtain spherical magnetite particles.
本発明における水酸化第一鉄を酸化する際の反応温度は６０〜１００℃である。６０℃未満では、飽和磁束密度が小さくなる。１００℃を超えても本発明の球状マグネタイト粒子が得られるが、工業的でない。 The reaction temperature when oxidizing ferrous hydroxide in the present invention is 60 to 100 ° C. If it is less than 60 degreeC, a saturation magnetic flux density will become small. Even if it exceeds 100 degreeC, the spherical magnetite particle | grains of this invention are obtained, but it is not industrial.
酸化方法としては空気等の酸素含有ガスや酸素ガスを液中に通気することや、過酸化水素等の酸化剤を添加する方法等があるが、酸素含有ガスを通気させる方法が一般的である。 As the oxidation method, there are a method of passing an oxygen-containing gas such as air or oxygen gas through the liquid, a method of adding an oxidizing agent such as hydrogen peroxide, etc., but a method of passing an oxygen-containing gas is common. .
また、反応終了後も６０〜１００℃の温度を維持しながら窒素ガスを通気させるのが好ましい。反応終了後も加温しながら窒素ガスを通気するのは、生成粒子の表面を安定化させ、シラン化合物の被覆状態が良くなる効果があるためである。 In addition, it is preferable to allow nitrogen gas to flow while maintaining the temperature of 60 to 100 ° C. even after the reaction is completed. The reason why the nitrogen gas is aerated while heating after the reaction is that the surface of the generated particles is stabilized and the coating state of the silane compound is improved.
本発明において使用されるリン化合物としては、ヘキサメタリン酸ナトリウム、第一リン酸アンモニウム等のリン酸塩、正リン酸、亜リン酸等の水溶性のリン酸塩が用いられ、その添加量はＦｅ３Ｏ４に対してＰ２Ｏ５換算で０．１５〜０．５重量％であり、好ましくは０．３〜０．４重量％である。０．１５重量％未満である場合には、目標とする磁気特性を達成できず、０．５重量％を超える量を添加しても効果は変わらず無駄であり、結晶成長速度に差が生じ粒度分布が悪くなるので好ましくない。 As the phosphorus compound used in the present invention, phosphates such as sodium hexametaphosphate and primary ammonium phosphate, and water-soluble phosphates such as normal phosphoric acid and phosphorous acid are used, and the amount added is Fe. against 3 O 4 is 0.15 to 0.5 wt% in terms of P 2 O 5, preferably from 0.3 to 0.4 wt%. If the amount is less than 0.15% by weight, the target magnetic properties cannot be achieved, and even if an amount exceeding 0.5% by weight is added, the effect is not changed, and the crystal growth rate is different. This is not preferable because the particle size distribution is deteriorated.
リン化合物の添加時期は、反応前の水酸化アルカリ中、第一鉄塩中、又はこれらを中和して得られた水酸化第一鉄中のいずれであっても良いが、磁性酸化鉄の結晶化が始まる前に添加しておく必要がある。 The timing of addition of the phosphorus compound may be any of alkali hydroxide before reaction, ferrous salt, or ferrous hydroxide obtained by neutralizing these, but magnetic iron oxide It must be added before crystallization begins.
本発明において使用されるケイ素化合物としては、水ガラス、ケイ酸ナトリウム、ケイ酸カリウム等の水溶性のケイ素化合物が用いられ、その添加量はＦｅ３Ｏ４に対してＳｉＯ２換算で０．７〜２．０重量％であり、好ましくは０．９〜１．５重量％である。０．７重量％未満である場合には、目標とする磁気特性を達成出来ず、２．０重量％を超える量を添加しても効果は変わらず無駄であり、粒度分布が悪くなるとともに、珪素化合物のマグネタイト粒子表面への露出量が多くなり、後工程でのシラン化合物の被覆状態に悪影響を及ぼすので好ましくない。 As the silicon compound used in the present invention, water-soluble silicon compounds such as water glass, sodium silicate, and potassium silicate are used, and the amount added is 0.7 in terms of SiO 2 with respect to Fe 3 O 4 . It is -2.0 weight%, Preferably it is 0.9-1.5 weight%. If it is less than 0.7% by weight, the target magnetic properties cannot be achieved, and even if an amount exceeding 2.0% by weight is added, the effect is not changed and the particle size distribution is deteriorated. The amount of exposure of the silicon compound to the surface of the magnetite particles increases, which adversely affects the coating state of the silane compound in the subsequent process, which is not preferable.
ケイ素化合物の添加時期は、反応前の水酸化アルカリ中、第一鉄塩中、又はこれらを中和して得られた水酸化第一鉄中のいずれであっても良いが、マグネタイトの結晶化が始まる前に添加しておく必要がある。 The addition time of the silicon compound may be any of alkali hydroxide before reaction, ferrous salt, or ferrous hydroxide obtained by neutralizing these, but crystallization of magnetite It is necessary to add before the start.
次に前記の球状マグネタイト粒子に代表される磁性酸化鉄粒子に対して、前記のシラン化合物を表面処理する。
磁性酸化鉄粒子は磁性を有するため、水系分散媒中で一次粒子の状態を維持するのは困難であり、二次粒径を出来る限り小さくするということが肝要である。
Next, the silane compound is surface-treated on magnetic iron oxide particles typified by the spherical magnetite particles.
Since magnetic iron oxide particles have magnetism, it is difficult to maintain the state of primary particles in an aqueous dispersion medium, and it is important to make the secondary particle size as small as possible.
また、磁性酸化鉄の二次粒径を小さくするためには、物理的な分散力だけではなく、水系分散媒中における磁性酸化鉄粒子の静電反発の利用が必要となる。しかるに、シラン化合物を添加する場合は、基体とする磁性酸化鉄の等電点から２ｐＨ程度離れているところを選択するのが良い。ただし、磁性酸化鉄がマグネタイトの場合、ｐＨ４より低いとマグネタイトが溶解するため均一被覆が達成できないので好ましくない。 In order to reduce the secondary particle size of magnetic iron oxide, it is necessary to use not only physical dispersion force but also electrostatic repulsion of magnetic iron oxide particles in an aqueous dispersion medium. However, when a silane compound is added, it is preferable to select a location that is about 2 pH away from the isoelectric point of the magnetic iron oxide as the substrate. However, when the magnetic iron oxide is magnetite, a pH lower than 4 is not preferable because the magnetite dissolves and uniform coating cannot be achieved.
シラン化合物を添加する際の、水系分散媒中における磁性酸化鉄の二次粒径は、０．９μm以下にするのが良い。０．９μｍより大きくすると、シラン化合物がマグネタイト表面に均一被覆せず、結果としてシラン化合物のトルエン中への溶出が多くなるので好ましくない。 The secondary particle size of the magnetic iron oxide in the aqueous dispersion medium when the silane compound is added is preferably 0.9 μm or less. When it is larger than 0.9 μm, the silane compound is not uniformly coated on the surface of the magnetite, and as a result, the elution of the silane compound into toluene is unfavorable.
一般的に無機材料へのシラン化合物の処理方法は湿式処理と乾式処理に大別されるが、本発明の目的を達成するためには湿式処理が望ましい。すなわち、磁性酸化鉄粒子表面を疎水化するための処理は、水系媒体中で磁性酸化鉄粒子の二次粒径を出来るだけ小さくした状態でシラン化合物を処理する方法が非常に好ましい。この疎水化処理方法は、撹拌混合機等を用いて無機材料と処理剤を乾式で混合する乾式処理とは異なり、磁性酸化鉄の粒子間距離を維持しつつ処理できるので、凝集した磁性酸化鉄粒子の表面に処理物が被覆するようなことは少なく、個々の粒子表面に均一に処理することが可能である。その結果、シラン化合物のトルエン中への溶出率を小さくすることが出来る。 In general, a method for treating an inorganic material with a silane compound is roughly classified into a wet treatment and a dry treatment, and a wet treatment is desirable to achieve the object of the present invention. That is, the treatment for hydrophobizing the surface of the magnetic iron oxide particles is very preferably a method in which the silane compound is treated with the secondary particle size of the magnetic iron oxide particles as small as possible in an aqueous medium. This hydrophobic treatment method is different from the dry treatment in which the inorganic material and the treatment agent are mixed by a dry method using a stirring mixer or the like, and can be treated while maintaining the distance between the particles of the magnetic iron oxide. The surface of the particles is rarely coated with the processed material, and can be uniformly processed on the surface of each particle. As a result, the elution rate of the silane compound into toluene can be reduced.
前記の湿式処理では、これまで乾式処理では磁性体粒子同士が凝集しやすくて、良好な処理が困難であった高粘性のカップリング剤も使用できるようになる。
前記の基体となる磁性酸化鉄を水中に懸濁させ、所定量のシラン化合物を添加し、１〜４８時間撹拌保持後、固液分離、洗浄、乾燥、粉砕する。
In the above-described wet processing, it is possible to use a high-viscosity coupling agent that has heretofore been difficult to satisfactorily process because the magnetic particles tend to aggregate together in the dry processing.
The magnetic iron oxide serving as the substrate is suspended in water, a predetermined amount of a silane compound is added, and after stirring for 1 to 48 hours, solid-liquid separation, washing, drying, and pulverization are performed.
添加する各種シラン化合物は、そのまま添加しても良く、あるいはアルコールやヘキサン等で希釈して添加する方法や予め加水分解処理を施したものを用いることも可能であり、これらの条件は各種シラン化合物の性状や特徴に応じて適宜選択されるものである。なお、シラン化合物の添加は全量を一度に添加しても良く、断続的に添加する方法でも良い。 The various silane compounds to be added may be added as they are, or a method of diluting with alcohol, hexane or the like, or those previously hydrolyzed can be used. These are appropriately selected according to the properties and characteristics of the. The silane compound may be added all at once, or intermittently.
処理温度については、シラン化合物の種類により異なるが、３０〜６０℃、好ましくは４０〜５０℃で行うのが良い。３０℃未満の場合には、磁性酸化鉄粒子へのシラン化合物の被覆速度が遅くなるので生産性や被覆層の均一性で劣り、その結果疎水化度が劣るので好ましくない。６０℃より高くなると被覆速度は速くなるが、シラン化合物同士の縮合が促進されるので、磁性酸化鉄粒子への均一被覆が達成できず、その結果、分散安定性、疎水化度のすべてが劣るので好ましくない。 About processing temperature, although it changes with kinds of silane compound, it is good to carry out at 30-60 ° C, preferably 40-50 ° C. When the temperature is lower than 30 ° C., the coating rate of the silane compound on the magnetic iron oxide particles becomes slow, so that the productivity and the uniformity of the coating layer are inferior. As a result, the degree of hydrophobicity is inferior. When the temperature is higher than 60 ° C., the coating speed is increased, but condensation between silane compounds is promoted, so that uniform coating onto the magnetic iron oxide particles cannot be achieved, and as a result, all of dispersion stability and hydrophobicity are inferior. Therefore, it is not preferable.
シラン化合物の処理時間については、１〜４８時間であり、１〜２４時間が好ましい。シラン化合物を添加するときの水系分散媒のｐＨは、用いるシラン化合物の種類、シラン化合物の加水分解の有無ならびに基体磁性酸化鉄の等電点により異なるが、基体磁性酸化鉄の二次粒径を小さくするためには、基体磁性酸化鉄の等電点から２ｐＨ程度離れているところを選択するのが好ましい。例えば、基体とする磁性酸化鉄がマグネタイト粒子の場合当該ｐＨ は４〜６、または９〜１１であり、ｐＨが４より低いとマグネタイト粒子が溶解するので好ましくない。一方、シラン化合物をそのまま添加する場合は、加水分解の促進に有利な酸性領域を選択した方が好ましい。すなわち、基体とする磁性酸化鉄粒子がマグネタイト粒子であり、かつシラン化合物をそのまま添加する場合における水系分散媒のｐＨは４〜６が好ましい。シラン化合物の被覆量が全体の８０％を超えてからは分散安定性を良くするためにｐＨを８〜９に高めるのが良い。 The treatment time for the silane compound is 1 to 48 hours, preferably 1 to 24 hours. The pH of the aqueous dispersion medium when the silane compound is added varies depending on the type of silane compound used, the presence or absence of hydrolysis of the silane compound, and the isoelectric point of the substrate magnetic iron oxide. In order to make it small, it is preferable to select a location that is about 2 pH away from the isoelectric point of the base magnetic iron oxide. For example, when the magnetic iron oxide used as the substrate is magnetite particles, the pH is 4 to 6 or 9 to 11. If the pH is lower than 4, the magnetite particles are dissolved, which is not preferable. On the other hand, when the silane compound is added as it is, it is preferable to select an acidic region advantageous for promoting hydrolysis. That is, the pH of the aqueous dispersion medium is preferably 4 to 6 when the magnetic iron oxide particles used as the base are magnetite particles and the silane compound is added as it is. After the coating amount of the silane compound exceeds 80% of the whole, it is preferable to increase the pH to 8 to 9 in order to improve the dispersion stability.
シラン化合物を処理した磁性酸化鉄の乾燥は１００℃未満が好ましい。１００℃を超えると、つまり乾燥温度を水の沸点以上にするとシラン化合物と磁性酸化鉄の反応が強固に行われる反面、縮合が進んだシラン化合物が磁性酸化鉄粒子同士を架橋して二次粒子が大きくなり、分散安定性が悪くなるので好ましくない。水分蒸発後、続けて同温度で熱処理を継続するのが良い。熱処理を行う目的で、水分蒸発後も同温度で加熱を継続することもできる。また、熱処理時間を短縮する目的で、熱処理の温度を高くしても良いが、粒子間の凝集が強くなるので、熱処理温度は１６０℃以下が好ましい。 The drying of the magnetic iron oxide treated with the silane compound is preferably less than 100 ° C. When the temperature exceeds 100 ° C., that is, when the drying temperature is higher than the boiling point of water, the reaction between the silane compound and the magnetic iron oxide is carried out strongly, while the condensed silane compound crosslinks the magnetic iron oxide particles to secondary particles. Is undesirably large because the dispersion stability deteriorates. After moisture evaporation, it is preferable to continue the heat treatment at the same temperature. For the purpose of heat treatment, heating can be continued at the same temperature after evaporation of moisture. Further, for the purpose of shortening the heat treatment time, the temperature of the heat treatment may be increased, but the heat treatment temperature is preferably 160 ° C. or less because aggregation between particles becomes strong.
シラン化合物は、一種もしくは二種以上を併用しても良いが、シラン化合物の種類により被覆速度が異なるため処理条件の選択が難しくなり、なるべく一種での処理が望ましい。 The silane compound may be used alone or in combination of two or more. However, since the coating speed varies depending on the type of silane compound, it becomes difficult to select treatment conditions, and treatment with one kind is desirable.
前記シラン化合物の添加量は、前記基体粒子の単位表面積当たり１．０〜２．５ｍｇ／ｍ２であることが好ましく、さらに１．５〜２．０ｍｇ／ｍ２であればより好ましい。この範囲であれば前記シラン化合物が粒子全体を覆えなくなり、従って疎水化度が低くなり樹脂とのなじみ性が悪くなるので好ましくない。 The addition amount of the silane compound is preferably 1.0 to 2.5 mg / m 2 , more preferably 1.5 to 2.0 mg / m 2 per unit surface area of the base particles. Within this range, the silane compound does not cover the entire particle, and therefore the degree of hydrophobicity is lowered and the compatibility with the resin is deteriorated.
シラン化合物の処理に用いる撹拌機は、ホモミキサーの如き高剪断力混合装置が望ましい。
マグネタイトスラリーを分散機等による機械的・物理的に撹拌し、さらにマグネタイトスラリーのｐＨを等電点から離れた領域に調整し、マグネタイト粒子同士の静電反発を利用しながらシラン化合物の表面処理を行う。湿式法であれば、酸化終了して得られたスラリー状態のマグネタイト粒子を湿式のまま乾燥工程を経ずに表面処理することが効率的であるが、乾式法で得られたものであっても、これを表面処理するために水分散媒中に懸濁させる際に機械的撹拌による分散と粒子同士の静電反発を利用による分散で二次粒径を小さくすることができ、結果として表面処理剤の均一処理が達成できる。
The stirrer used for the treatment of the silane compound is preferably a high shear mixing device such as a homomixer.
The magnetite slurry is mechanically and physically stirred by a disperser, etc., and the pH of the magnetite slurry is adjusted to a region away from the isoelectric point, and the surface treatment of the silane compound is performed using electrostatic repulsion between the magnetite particles. Do. If it is a wet method, it is efficient to surface-treat the magnetite particles in a slurry state obtained after completion of oxidation without being subjected to a drying step in a wet state, but even if it is obtained by a dry method When suspended in an aqueous dispersion medium for surface treatment, the secondary particle size can be reduced by dispersion using mechanical stirring and electrostatic repulsion between particles, resulting in surface treatment. Uniform treatment of the agent can be achieved.
このようにして得られた本発明の疎水性球状磁性酸化鉄粒子は、各種分散媒中での分散性、分散安定性、疎水化度、およびトルエン溶出量に優れており、特に重合トナー用を始めとする静電複写磁性トナー用、電子ペーパー用として好適である。 The thus obtained hydrophobic spherical magnetic iron oxide particles of the present invention are excellent in dispersibility, dispersion stability, hydrophobicity, and toluene elution amount in various dispersion media. Suitable for electrostatic copying magnetic toner and electronic paper.
後述の実施例に示す通り、カップリング剤は、添加した量のほぼ全量が磁性酸化鉄粒子粉末の粒子表面に被覆される。
以下に、各特性の測定方法について説明する。
（ＴＥＭによる体積基準における累積平均粒子径（μｍ）の測定）
透過型電子顕微鏡（ＪＥＯＬ製「ＪＥＭ−２００ＣＸ」（商品名））を用い、倍率３０,０００倍にて試料粒子の形状観察、及び３００個の粒子について円相当径の粒子径測定を行い、一次粒子の体積基準における累積平均粒子径（ｄ５０％）を算出した。
（比表面積（ｍ２／ｇ）の測定）
島津-マイクロメリティクス製「ＧＥＭＩＮＩ２３７５」を用いてＢ．Ｅ．Ｔ．一点法（定圧法）で測定した。
(シラン化合物の被覆量（ｍｇ／ｍ２)の測定)
まず測定溶液の作製手順を述べる。５００℃で焼成した、シラン化合物を被覆した試料粉末の１ｇを１０ｍｌの濃塩酸中で加熱溶解した後、純水を加えて全量を１００ｍｌとした（母液）。母液から２０ｍｌを分取し、純水を加えて全量を１００ｍｌとした溶液（測定用）を作製した。さらに母液から２０ｍｌを分取し、原子吸光分析用のシリカ標準液を所定量添加した後、純水を加えて全量を１００ｍｌとした溶液（標準化用）を作製した。
As shown in the examples described later, almost the entire amount of the added coupling agent is coated on the surface of the magnetic iron oxide particle powder.
Below, the measuring method of each characteristic is demonstrated.
(Measurement of cumulative average particle size (μm) on a volume basis by TEM)
Using a transmission electron microscope (“JEM-200CX” (trade name) manufactured by JEOL), the shape of the sample particles was observed at a magnification of 30,000 times, and the particle diameter of the equivalent circle diameter was measured for 300 particles. The cumulative average particle diameter (d50%) on the volume basis of the particles was calculated.
(Measurement of specific surface area (m 2 / g))
Shimadzu-“MEMINI2375” manufactured by Micromeritics E. T.A. It was measured by the single point method (constant pressure method).
(Measurement of coating amount of silane compound (mg / m 2 ))
First, the procedure for preparing the measurement solution will be described. 1 g of the sample powder coated with the silane compound, which was baked at 500 ° C., was dissolved by heating in 10 ml of concentrated hydrochloric acid, and then pure water was added to make the total volume 100 ml (mother liquor). 20 ml was taken from the mother liquor, and pure water was added to make a total solution of 100 ml (for measurement). Further, 20 ml was taken from the mother liquor, a predetermined amount of a silica standard solution for atomic absorption analysis was added, and then a pure water was added to make a total amount of 100 ml (for standardization).
次にＩＣＰ発光分析装置(Ｎｉｐｐｏｎ Ｊａｒｒｅｌｌ−Ａｓｈ製「ＩＣＡＰ−５７
５」（商品名）)を用いて標準添加法にて測定溶液中のＳｉ量（ｍｇ）を求め、粉末中の
Ｓｉ量（％）を算出した。基体粉末についてもシラン化合物を被覆した試料粉末と同様の手順で測定溶液を作製し、ＩＣＰ発光分析装置分析により粉末中のＳｉ量（％）を求めた。
Next, an ICP emission spectrometer (“ICAP-57” manufactured by Nippon Jarrel-Ash)
5 ”(trade name)) was used to obtain the Si amount (mg) in the measurement solution by the standard addition method, and the Si amount (%) in the powder was calculated. For the base powder, a measurement solution was prepared in the same procedure as the sample powder coated with the silane compound, and the Si amount (%) in the powder was determined by ICP emission analyzer analysis.
シラン化合物を被覆した試料粉末のＳｉ量（％）から基体粉末のＳｉ量（％）を引いた値が、シラン化合物由来のＳｉ量（％）となり、このＳｉ量（％）をシラン化合物量（％）に換算した。Ｓｉ量（％）をシラン化合物量（％）に換算するための係数（Ｎ）は、シラン化合物の種類によって異なるが、例えば、シラン化合物がデシルトリメトキシシランの場合、Ｓｉ量（％）に７．７３９を乗ずれば、基体粒子の表面に被覆しているデシルトリメトキシシランの量（％）となり、これを試料１ｇ当たりの量（ｍｇ／ｇ）に換算する。この値を基体の比表面積（ｍ２／ｇ）で除して被覆量（ｍｇ／ｍ２）を求めた。すなわち、シラン化合物の被覆量は、次式で求められる。 The value obtained by subtracting the Si amount (%) of the base powder from the Si amount (%) of the sample powder coated with the silane compound is the Si amount (%) derived from the silane compound, and this Si amount (%) is used as the silane compound amount (%). %). The coefficient (N) for converting the Si amount (%) into the silane compound amount (%) varies depending on the type of the silane compound. For example, when the silane compound is decyltrimethoxysilane, the Si amount (%) is 7%. When multiplied by .739, it becomes the amount (%) of decyltrimethoxysilane coated on the surface of the substrate particles, and this is converted to the amount per 1 g of the sample (mg / g). The coating amount (mg / m 2 ) was determined by dividing this value by the specific surface area (m 2 / g) of the substrate. That is, the coating amount of the silane compound is obtained by the following formula.
(トルエン溶出率（％）の測定)
まず、５０ｍｌのスクリュー管瓶に試料粉末を２０．０ｇ、続けて試薬一級トルエンを１３．０ｇ計りとった。スクリュー管瓶に蓋をして１０ｓｅｃ間手で軽く振とうした後、水を入れた超音波洗浄機(ＫＡＩＪＯ ＤＥＮＫＩ ＣＯ．ＬＴＤ製「ＵＬＴＲＡＳＯＮＩＣ ＣＬＥＡＮＥＲ ＣＡ−２４８１」（商品名）)にセットし、６０分間超音波を照射した。その後、遠心分離器（株式会社 久保田製作所製「テーブルトップ遠心機 ５４２０」（商品名））を用いて２，０００ｒｐｍで１５分間遠心分離を行った後、速やかに上澄みを取り除き、沈降物をスパチュラを用いて時計皿に取り出した。時計皿に取り出した沈降物を９０℃に調整した乾燥機内に１時間入れてトルエンを揮散させた。コーヒーミルで解砕したものを（１）に示す手順に従い、トルエン溶出前後のシラン化合物被覆量を求め、次式によりトルエン溶出率を算出した。
(Measurement of toluene elution rate (%))
First, 20.0 g of sample powder was measured in a 50 ml screw tube, and then 13.0 g of reagent primary toluene was weighed. Cover the screw tube bottle and shake gently for 10 seconds, then set it in an ultrasonic cleaner with water ("ULTRASONIC CLEANER CA-2481" (trade name) manufactured by KAIJO DENKI CO. LTD), 60 Ultrasound was irradiated for minutes. Then, after centrifuging at 2,000 rpm for 15 minutes using a centrifuge (“Table Top Centrifuge 5420” (trade name) manufactured by Kubota Corporation), the supernatant is immediately removed, and the precipitate is removed with a spatula. Used to remove to watch glass. The sediment taken out to the watch glass was put into a drier adjusted to 90 ° C. for 1 hour to volatilize toluene. According to the procedure shown in (1), the silane compound coating amount before and after elution of toluene was determined for the product crushed by the coffee mill, and the toluene elution rate was calculated by the following formula.
(疎水化度（％）の測定)
目開き１ｍｍのふるいで通過したものを疎水化度測定用試料粉末とした。試験粉末０．１０ｇを容量５０ｍｌビーカーの水１０ｍｌに添加した。これをマグネチックスターラーで１００ｒｐｍで撹拌しながら、メタノールをマイクロチューブポンプ（ＴＯＫＹＯ ＲＩＫＡＫＩＫＡＩ ＣＯ．ＬＴＤ製「ＭＩＣＲＯ ＴＵＢＥ ＰＵＭＰ ＭＰ−３」(商品名)）を用いて液中に液底部より徐々に添加した。液面に浮遊した試験粉末が確認されなくなった点を試験の終点とした。疎水化度は、試験終点までに添加したメタノールの体積と水１０ｍｌ混合液中のメタノールの体積百分率として表した。
(水分量の測定)
水分量は平沼産業株式会社製「平沼微量水分測定装置ＡＱ−６」（商品名）で測定したもので、１００℃で蒸発する水分量である。また、３０℃、相対湿度８１％に調整した環境試験機（株式会社カトー製）内に、試験粉末の５ｇを入れた秤量瓶を置き、１週間経時したものの水分量と試験する前の水分量との差を、高温高湿下での吸着水分量とした。
(スチレン・ｎブチルアクリレート分散媒中の粒度分布の測定)
スチレン（シグマアルドリッチジャパン株式会社製ＳＡＪ一級）の３２ｇおよびｎ−ブチルアクリレート（東京化成工業株式会社製試薬）の８ｇを１５０ｍＬのガラス瓶に量りとり、これをディスパーマット装置（ＶＭＡ−ＧＥＴＺＭＡＮＮ製）に備え付けの器具で固定した。ディスパーマット装置に３０ｍｍφのノコギリ歯状ディスクを取り付け６００ｒｐｍで撹拌した状態で、試料粉末の３６ｇを約１分かけて投入し、続けて４，０００ｒｐｍまで回転数を上げて３０分間保持することにより、粒度分布測定用の分散スラリーを調製した。分散スラリーの粒度分布を粒度分布測定装置（日機装製「マイクロトラックＵＰＡ」（商品名））を用いて測定し、体積基準における累積平均粒子径（ｄ５０％）（μｍ）を求め、さらに前記数１の式に従いｄ８４％とｄ１６％からＳＤ値（μｍ）を算出した。
（トルエン中での分散安定性）
１００ｍｌポリビーカーに試験粉末の１．５ｇ、トルエン５０ｍｌをこの順番で入れ、スパチュラでかき混ぜてスラリー化した。このスラリーが入った１００ｍｌポリビーカーをステンレス製容器内の中央部に置き、分散中の温度上昇を抑制する目的でステンレス製容器内に氷水を入れた。次に超音波ホモジナイザー（ＣＨＯ−ＯＮＰＡ ＫＯＧＹＯ製「ＵＬＴＲＡ ＳＯＮＩＣＧＥＮＥＲＡＴＯＲ」（商品名））をスラリー中に浸せきし、５分間分散した。分散終了スラリーを５０ｍＬスクリュー管瓶に移し、静置観察した。２時間静置後、スクリュー管瓶の背面から懐中電灯を当てることにより、光が透過する場合を分散安定性が×、光が透過しない場合は分散安定性が○とした。
（Ｐ２Ｏ５及びＳｉＯ２含有量分析（重量％））
試験粉末を溶解し、ＩＣＰ(Ｎｉｐｐｏｎ Ｊａｒｒｅｌｌ−Ａｓｈ製「ＩＣＡＰ−５７５」（商品名）)にてＰおよびＳｉ含有量を測定し、それぞれＰ２Ｏ５及びＳｉＯ２含有量に換算した。
（磁気特性の測定）
振動試料型磁力計（東英工業製「ＶＳＭ−３」（商品名））を使用し、外部磁場７９．６ｋＡ／ｍにて飽和磁化：σs（Ａｍ２／ｋｇ）、及び残留磁化：σr（Ａｍ２／ｋｇ）を測定した。以下に操作の詳細を示す。まず、標準試料を使用し、振動試料型磁力計の＋３９８ｋＡ／ｍ印加時の磁化量を５ＥＭＵに調整した。内容量が０．０５６５５ｃｍ３のセルに、試料粉末を充填密度として２．２０〜２．４０ｇ／ｃｍ３の範囲になるように充填した。外部磁場を＋７９．６ｋＡ／ｍに設定し、外部磁場が０Ａ／ｍから試料への印加を行った。＋６３．７ｋＡ／ｍ付近より印加速度を下げ、＋７８ｋＡ／ｍ以上では印加速度を最低の２０ｍｉｎ／Ｆｕｌｌ−ｓｃａｌｅにし、＋７９．６ｋＡ／ｍ以上に印加しないようにした。＋７９．６ｋＡ／ｍの印加はＧＡＵＳＳ ＭＥＴＥＲの出力値が ＋１．０００ Ｖであることで確認した。＋７９．６ｋＡ／ｍ印加させた状態の磁化量（＋σｓ）としてＭＡＩＮ ＡＭＰＬＩＦＩＥＲの出力値（Ｖ）を読み取った。磁化量は時間経過とともに緩やかに変化するので、出力値の読み取りは＋７９．６ｋＡ／ｍの印加を確認した時点で速やかに行った。＋σｓ値を読み取った後、減磁させた。外部磁場が０Ａ／ｍであることを確認し、磁場を反転して−７９．６ｋＡ／ｍまで印加させた。外部磁場０Ａ／ｍにおける残留磁化量の＋σｒ値を求めた。それぞれは外部磁場変化に伴う磁化量の推移をレコーダーに出力し紙面上より目視で読み取った。＋σｒを求める際の印加速度は７ｍｉｎ／Ｆｕｌｌｓｃａｌｅにした。＋σｒ値が読み取り可能と判断した後、印加速度を速くして−７９．６ｋＡ／ｍまで印加させ、−７９．６ｋＡ／ｍ印加させた状態の磁化量（−σｓ）としてＭＡＩＮ ＡＭＰＬＩＦＩＥＲの出力値を読み取った。＋σｓの読み取り操作と同様に、−６３．４ｋＡ／ｍ以上は印加速度を下げ、−７８ｋＡ／ｍ以上の印加速度は最低の２０ｍｉｎ／Ｆｕｌｌｓｃａｌｅにし、７９．６ｋＡ／ｍ以上に印加しないようにした。−７９．６ｋＡ／ｍの確認をＧＡＵＳＳ ＭＥＴＥＲの出力値で行う点及び−σｓとしてＭＡＩＮ ＡＭＰＬＩＦＩＥＲの出力値の読み取りを速やかに行う点は＋σｓと同様である。−σｓ値を読み取った後、減磁させた。外部磁場０Ａ／ｍを確認し、磁場を反転して＋７９．６ｋＡ／ｍまで印加させた。外部磁場０Ａ／ｍにおける残留磁化量の−σｒ値を求めた。これらも外部磁場変化に伴う磁化量の推移をレコーダーに出力し紙面上より目視で読み取った。また、印加速度は７ｍｉｎ／Ｆｕｌｌｓｃａｌｅに設定した。
(Measurement of hydrophobicity (%))
A sample powder for measuring the degree of hydrophobicity was passed through a sieve having an aperture of 1 mm. 0.10 g of the test powder was added to 10 ml of water in a 50 ml beaker. While stirring this at 100 rpm with a magnetic stirrer, methanol was gradually added to the liquid from the bottom using a microtube pump (“MICRO TUBE PUMP MP-3” (trade name) manufactured by TOKYO RIKAKAI CO. LTD). . The point at which the test powder suspended on the liquid surface was not confirmed was taken as the end point of the test. The degree of hydrophobicity was expressed as the volume percentage of methanol added by the end of the test and the volume percentage of methanol in a 10 ml water mixture.
(Measurement of water content)
The amount of water was measured with “Hiranuma trace moisture measuring device AQ-6” (trade name) manufactured by Hiranuma Sangyo Co., Ltd., and is the amount of water evaporated at 100 ° C. A weighing bottle containing 5 g of the test powder was placed in an environmental testing machine (manufactured by Kato Co., Ltd.) adjusted to 30 ° C. and relative humidity 81%. The amount of adsorbed water under high temperature and high humidity was defined as the difference between the two.
(Measurement of particle size distribution in styrene / n-butyl acrylate dispersion medium)
32 g of styrene (Sigma Aldrich Japan Co., Ltd. SAJ first grade) and 8 g of n-butyl acrylate (Tokyo Kasei Kogyo Co., Ltd. reagent) are weighed in a 150 mL glass bottle, and this is equipped with a disperse mat apparatus (manufactured by VMA-GETZMANN). It was fixed with the instrument. With a 30 mmφ sawtooth disk attached to the Dispermat device and stirring at 600 rpm, 36 g of the sample powder was added over about 1 minute, and then the rotation speed was increased to 4,000 rpm and held for 30 minutes, A dispersion slurry for measuring the particle size distribution was prepared. The particle size distribution of the dispersed slurry is measured using a particle size distribution measuring apparatus (“MICROTRACK UPA” (trade name) manufactured by Nikkiso) to determine the cumulative average particle diameter (d50%) (μm) on a volume basis, and the above formula 1 The SD value (μm) was calculated from d84% and d16% according to the formula:
(Dispersion stability in toluene)
In a 100 ml poly beaker, 1.5 g of the test powder and 50 ml of toluene were put in this order, and stirred with a spatula to make a slurry. A 100 ml poly beaker containing this slurry was placed in the center of the stainless steel container, and ice water was placed in the stainless steel container for the purpose of suppressing temperature rise during dispersion. Next, an ultrasonic homogenizer (“ULTRA SONIC GENERATOR” (trade name) manufactured by CHO-ONPA KOGYO) was immersed in the slurry and dispersed for 5 minutes. The dispersion-finished slurry was transferred to a 50 mL screw tube and observed by standing. After standing for 2 hours, by applying a flashlight from the back of the screw tube bottle, the dispersion stability was evaluated as x when light was transmitted, and the dispersion stability was evaluated as ○ when light was not transmitted.
(P 2 O 5 and SiO 2 content analysis (wt%))
The test powder was dissolved, and P and Si contents were measured by ICP (“ICAP-575” (trade name) manufactured by Nippon Jarrel-Ash), and converted into P 2 O 5 and SiO 2 contents, respectively.
(Measurement of magnetic properties)
Using a vibrating sample magnetometer (“VSM-3” (trade name) manufactured by Toei Kogyo Co., Ltd.) with an external magnetic field of 79.6 kA / m, saturation magnetization: σs (Am 2 / kg), and residual magnetization: σr ( Am 2 / kg) was measured. Details of the operation are shown below. First, a standard sample was used, and the amount of magnetization of a vibrating sample magnetometer when +398 kA / m was applied was adjusted to 5 EMU. Contents within the cells of 0.05655cm 3, was packed to be in the range of 2.20~2.40g / cm 3 the sample powder as packing density. The external magnetic field was set to +79.6 kA / m, and the external magnetic field was applied to the sample from 0 A / m. The application speed was lowered from around +63.7 kA / m, and at +78 kA / m or more, the application speed was set to the minimum of 20 min / Full-scale and not applied to +79.6 kA / m or more. Application of +79.6 kA / m was confirmed by an output value of GAUSS METER being +1.000 V. The output value (V) of MAIN AMPLIFIER was read as the amount of magnetization (+ σs) in a state where +79.6 kA / m was applied. Since the amount of magnetization changes gradually with the passage of time, the output value was read promptly when the application of +79.6 kA / m was confirmed. After reading the + σs value, it was demagnetized. After confirming that the external magnetic field was 0 A / m, the magnetic field was reversed and applied to -79.6 kA / m. The + σr value of the residual magnetization amount at an external magnetic field of 0 A / m was obtained. In each case, the transition of the magnetization amount accompanying the change in the external magnetic field was output to a recorder and read visually from the paper. The application speed for obtaining + σr was 7 min / Fullscale. After determining that the + σr value can be read, the application speed is increased to −79.6 kA / m, and the MAIN AMPLIFIER output value is set as the amount of magnetization (−σs) when −79.6 kA / m is applied. I read it. Similar to the + σs reading operation, the application speed was decreased at −63.4 kA / m or more, the application speed at −78 kA / m was set to the minimum 20 min / Fullscale, and no application was performed at 79.6 kA / m or more. The point that the confirmation of −79.6 kA / m is performed with the output value of GAUSS METER and the point that the output value of MAIN AMPLIFIER is quickly read as −σs are the same as + σs. After reading the -σs value, demagnetization was performed. An external magnetic field of 0 A / m was confirmed, and the magnetic field was reversed and applied to +79.6 kA / m. The -σr value of the residual magnetization amount at an external magnetic field of 0 A / m was obtained. In these cases, the transition of the magnetization amount accompanying the change in the external magnetic field was output to a recorder and read visually from the paper. The application speed was set to 7 min / Fullscale.
上記の操作により読み取った正負２つのσｒ及びσｓにおける絶対値の平均値を、外部磁場７９．６ｋＡ／ｍのσｒ及びσｓとした。
（等電点の測定）
基体粒子の等電点をＺＥＴＡＲ−ＭＥＴＥＲＩＮＣ．製のＺＥＴＡ−ＭＥＴＥＲを用いて測定した。
（基体粒子スラリーの体積基準における累積平均粒子径の測定）
基体粒子の分散スラリーの粒度分布を粒度分布測定装置（日機装製「マイクロトラックＨＲＡ」（商品名））を用いて測定し、体積基準における累積平均粒子径（μm）を求めた。
The average value of the absolute values of the two positive and negative σr and σs read by the above operation was taken as σr and σs of the external magnetic field of 79.6 kA / m.
(Measurement of isoelectric point)
The isoelectric point of the substrate particles is determined according to ZETAR-METERINC. It measured using manufactured ZETA-METER.
(Measurement of cumulative average particle diameter based on volume of substrate particle slurry)
The particle size distribution of the dispersed slurry of the base particles was measured using a particle size distribution measuring device (“MICROTRACK HRA” (trade name) manufactured by Nikkiso), and the cumulative average particle size (μm) on a volume basis was determined.
以下、本発明の効果を示す実施例について説明するが、以下の実施例は単に例示のために示すものであり、発明の範囲がこれらによって制限されるものではない。なお、以下「Ｌ」はリットルを示す。 Hereinafter, examples showing the effects of the present invention will be described. However, the following examples are provided for illustrative purposes only, and the scope of the invention is not limited by these examples. Hereinafter, “L” indicates liters.
基体粒子の製造例Ａ：反応タンクに１８．５ｋｇの水酸化ナトリウムを含む水溶液１８０Ｌを入れ４０℃に調整した後、硫酸第一鉄水溶液をｐＨが８．５に達するまで添加した。その後、１ｍｏｌ／Ｌ ＮａＯＨでｐＨを９．０に調整した後、鉄濃度を３４ｇ／Ｌ、液量を４００Ｌとし、３０分間保持した。毎分１００Ｌで空気を吹き込み、酸化率（Ｆｅ３＋／ｔ−Ｆｅ重量比）が１０％になるまで酸化した。このスラリーを９０℃に調整後、毎分５０Ｌで空気を吹き込みながら酸化率６８％まで酸化した。その後、毎分８０Ｌの窒素ガスを吹き込みながら３時間撹拌保持して反応終了とした。生成粒子は、常法により、ろ過、水洗、リパルプしてシラン化合物処理用の基体スラリーとした。 Production Example A of Base Particles: 180 L of an aqueous solution containing 18.5 kg of sodium hydroxide was placed in the reaction tank and adjusted to 40 ° C., and then an aqueous ferrous sulfate solution was added until the pH reached 8.5. Thereafter, the pH was adjusted to 9.0 with 1 mol / L NaOH, the iron concentration was 34 g / L, the liquid volume was 400 L, and the mixture was held for 30 minutes. Air was blown at 100 L / min, and oxidation was performed until the oxidation rate (Fe 3+ / t-Fe weight ratio) reached 10%. After adjusting this slurry to 90 ° C., it was oxidized to an oxidation rate of 68% while blowing air at 50 L / min. Thereafter, the reaction was terminated by stirring and holding for 3 hours while blowing 80 L of nitrogen gas per minute. The produced particles were filtered, washed with water, and repulped by a conventional method to form a substrate slurry for silane compound treatment.
基体粒子の製造例Ｂ：硫酸第一鉄水溶液を添加する前の、４０℃に調整した水酸化ナトリウム水溶液中に、ヘキサメタリン酸ナトリウムを１２９．６ｇ（Ｆｅ３Ｏ４に対し、Ｐ２Ｏ５換算で０．４８重量％に該当する）添加し、毎分１００Ｌで空気を吹き込み、酸化率（Ｆｅ３＋／ｔ−Ｆｅ重量比）が８％になるまで酸化すること以外は、製造例Ａと同様の方法で基体スラリーを作製した。 Production Example B of Base Particles: In a sodium hydroxide aqueous solution adjusted to 40 ° C. before addition of ferrous sulfate aqueous solution, 129.6 g of sodium hexametaphosphate (in terms of P 2 O 5 with respect to Fe 3 O 4) The same as in Production Example A, except that air is blown at 100 L / min and oxidation is performed until the oxidation rate (Fe 3+ / t-Fe weight ratio) reaches 8%. A substrate slurry was prepared by the method described above.
基体粒子の製造例Ｃ：硫酸第一鉄水溶液を添加する前の、４０℃に調整した水酸化ナトリウム水溶液中に、ＳｉＯ２として４１３．５ｇ／Ｌのケイ酸化ナトリウム溶液を４１３．６ｍＬ（Ｆｅ３Ｏ４に対し、ＳｉＯ２換算で０．９１重量％に該当する）添加すること以外は、製造例Ａと同様の方法で基体スラリーを作製した。 Production Example C of Base Particles: 413.6 mL (Fe 3) of 413.5 g / L sodium silicate solution as SiO 2 was added to a sodium hydroxide aqueous solution adjusted to 40 ° C. before adding the ferrous sulfate aqueous solution. A substrate slurry was prepared in the same manner as in Production Example A, except that it was added to O 4 ( corresponding to 0.91% by weight in terms of SiO 2 ).
基体粒子の製造例Ｄ：硫酸第一鉄水溶液を添加する前の、４０℃に調整した水酸化ナトリウム水溶液中に、ヘキサメタリン酸ナトリウム８６．４ｇ（Ｆｅ３Ｏ４に対し、Ｐ２Ｏ５換算で０．３２重量％に該当する）及びＳｉＯ２として４１３．５ｇ／Ｌのケイ酸ナトリウム溶液６８１．７ｍＬ（Ｆｅ３Ｏ４に対し、ＳｉＯ２換算で１．５０重量％に該当する）を添加し、毎分１００Ｌで空気を吹き込み、酸化率（Ｆｅ３＋／ｔ−Ｆｅ重量比）が８％になるまで酸化すること以外は、製造例Ａと同様の方法で基体スラリーを作製した。 Production Example D of Base Particles: In a sodium hydroxide aqueous solution adjusted to 40 ° C. before adding the ferrous sulfate aqueous solution, 86.4 g of sodium hexametaphosphate (in terms of P 2 O 5 with respect to Fe 3 O 4) 0.32 wt%) and 681.7 mL of 413.5 g / L sodium silicate solution as SiO 2 (corresponding to 1.50 wt% in terms of SiO 2 with respect to Fe 3 O 4 ) A base slurry was prepared in the same manner as in Production Example A, except that air was blown at 100 L / min and oxidation was performed until the oxidation rate (Fe 3+ / t-Fe weight ratio) reached 8%.
基体粒子の製造例Ｅ：硫酸第一鉄水溶液を添加する前の、４０℃に調整した水酸化ナトリウム水溶液中に、ヘキサメタリン酸ナトリウム１２９．６ｇ（Ｆｅ３Ｏ４に対し、Ｐ２Ｏ５換算で０．４８重量％に該当する）及びＳｉＯ２として４１３．５ｇ／Ｌのケイ酸ナトリウム溶液４５４．５ｍＬ（Ｆｅ３Ｏ４に対し、ＳｉＯ２換算で１．００重量％に該当する）を添加すること以外は、製造例Ａと同様の方法で基体スラリーを作製した。 Production Example E of Base Particles: In a sodium hydroxide aqueous solution adjusted to 40 ° C. before adding an aqueous ferrous sulfate solution, 129.6 g of sodium hexametaphosphate (in terms of P 2 O 5 with respect to Fe 3 O 4) 0.445 wt%) and 454.5 mL of 413.5 g / L sodium silicate solution as SiO 2 (corresponding to 1.00 wt% in terms of SiO 2 with respect to Fe 3 O 4 ) Except for this, a base slurry was prepared in the same manner as in Production Example A.
基体粒子の製造例Ｆ：反応タンクに１９．５ｋｇの水酸化ナトリウムを含む水溶液１８０Ｌを入れ、４０℃に調整した後、ヘキサメタリン酸ナトリウム７６．２ｇ（Ｆｅ３Ｏ４に対し、Ｐ２Ｏ５換算で０．３２重量％に該当する）、及びＳｉＯ２として４１３．５ｇ／Ｌのケイ酸ナトリウム溶液４０１．０ｍＬ（Ｆｅ３Ｏ４に対し、ＳｉＯ２換算で１．００重量％に該当する）を添加した。これに硫酸第一鉄水溶液を加え、鉄濃度を３０ｇ／Ｌ、液量を４００Ｌとし、スラリーのアルカリ濃度を８０ｍｍｏｌ／Ｌに調整した。上記水酸化第一鉄水溶液に４０℃で過酸化水素水を加え、酸化率１０％まで酸化した。続けてスラリーの温度を９０℃に調整後、撹拌を行いながら、毎分５０Ｌの空気を吹き込み酸化率６８％まで酸化した。生成粒子は、常法によりろ過、水洗、リパルプしてシラン化合物処理用の基体スラリーとした。 Base Particle Production Example F: After putting 180 L of an aqueous solution containing 19.5 kg of sodium hydroxide into a reaction tank and adjusting to 40 ° C., 76.2 g of sodium hexametaphosphate (in terms of P 2 O 5 with respect to Fe 3 O 4) And 401.0 mL of 413.5 g / L sodium silicate solution as SiO 2 (corresponding to 1.00 wt% in terms of SiO 2 with respect to Fe 3 O 4 ) Added. A ferrous sulfate aqueous solution was added thereto, the iron concentration was 30 g / L, the liquid volume was 400 L, and the alkali concentration of the slurry was adjusted to 80 mmol / L. Hydrogen peroxide water was added to the ferrous hydroxide aqueous solution at 40 ° C. to oxidize to an oxidation rate of 10%. Subsequently, after adjusting the temperature of the slurry to 90 ° C., 50 L of air was blown per minute while stirring to oxidize to an oxidation rate of 68%. The generated particles were filtered, washed with water, and repulped by a conventional method to obtain a base slurry for silane compound treatment.
基体粒子の製造例Ｇ：反応タンクに１９．１ｋｇの水酸化ナトリウムを含む水溶液１８０Ｌを入れ、４０℃に調整した後、ケイ酸ナトリウムＳｉＯ２として４１３．５ｇ／Ｌのケイ酸ナトリウム溶液４０１ｍＬ（Ｆｅ３Ｏ４に対し、ＳｉＯ２換算で１．００重量％に該当する）を添加し、硫酸第一鉄水溶液をｐＨ値が１１．０に達するまで添加した。鉄濃度を３０ｇ／Ｌ、液量を４００Ｌに調整した。このスラリーを９０℃に調整後、撹拌しながら、毎分５０Ｌで空気を吹き込み、酸化率６８％まで酸化した。生成粒子は、常法によりろ過、水洗、リパルプしてシラン化合物処理用の基体スラリーとした。 Production Example G of Base Particles: After putting 180 L of an aqueous solution containing 19.1 kg of sodium hydroxide in a reaction tank and adjusting to 40 ° C., 401 mL of a 413.5 g / L sodium silicate solution as sodium silicate SiO 2 (Fe 3 O 4 ) (corresponding to 1.00% by weight in terms of SiO 2 ) was added, and an aqueous ferrous sulfate solution was added until the pH value reached 11.0. The iron concentration was adjusted to 30 g / L, and the liquid volume was adjusted to 400 L. After adjusting this slurry to 90 ° C., air was blown at 50 L / min while stirring to oxidize the slurry to an oxidation rate of 68%. The generated particles were filtered, washed with water, and repulped by a conventional method to obtain a base slurry for silane compound treatment.
基体粒子の製造例Ｈ：製造例Ｂで得られた生成粒子を定法により、ろ過、水洗、乾燥後、毎分１Ｌの空気を流しなら、２５０℃で加熱酸化を行った。加熱酸化したものを、ハイシェアーミキサーを用いて水中にリパルプし、シラン化合物処理用の基体スラリーを得た。 Production Example H of Base Particles: The produced particles obtained in Production Example B were filtered, washed with water and dried by a conventional method, and then heated and oxidized at 250 ° C. when flowing 1 L of air per minute. The heat-oxidized product was repulped into water using a high shear mixer to obtain a substrate slurry for silane compound treatment.
基体粒子の製造例Ｉ：硫酸第一鉄水溶液を添加する前の、４０℃に調整した水酸化ナトリウム水溶液中に、ヘキサメタリン酸ナトリウム９４．５ｇ（Ｆｅ３Ｏ４に対し、Ｐ２Ｏ５換算で０．３５重量％に該当する）及びＳｉＯ２として４１３．５ｇ／Ｌのケイ酸ナトリウム溶液４０９．０ｍＬ（Ｆｅ３Ｏ４に対し、ＳｉＯ２換算で０．９０重量％に該当する）を添加し、毎分１００Ｌで空気を吹き込み、酸化率（Ｆｅ３＋／ｔ−Ｆｅ重量比）が６％になるまで酸化すること以外は、製造例Ａと同様の方法で基体スラリーを作製した。 Production Example I of Base Particles: In a sodium hydroxide aqueous solution adjusted to 40 ° C. before adding the ferrous sulfate aqueous solution, 94.5 g of sodium hexametaphosphate (in terms of P 2 O 5 with respect to Fe 3 O 4) 0.35 wt%) and 409.0 mL of 413.5 g / L sodium silicate solution as SiO 2 (corresponding to 0.90 wt% in terms of SiO 2 with respect to Fe 3 O 4 ) A base slurry was prepared in the same manner as in Production Example A, except that air was blown at 100 L / min and oxidation was performed until the oxidation rate (Fe 3+ / t-Fe weight ratio) reached 6%.
基体粒子の製造例Ａ〜Ｉについて纏めたものを表１に示す。また、シラン化合物の種類について纏めたものを表２に示す。 Table 1 summarizes the production examples A to I of the base particles. Table 2 summarizes the types of silane compounds.
（実施例１）
製造例Ａの基体粒子を用いた。基体の等電点を測定したところｐＨ８．０であった。基体スラリーのｐＨを５．０に調整し、ＴＫホモミキサー(６,０００ｒｐｍ）で３０分間分散した。分散スラリーの平均粒子径は０．７２μmであった。分散スラリーの温度を４０℃、基体濃度を１００ｇ／Ｌに調整後、塩酸：水＝１：９（体積比）の希塩酸でスラリーｐＨを５．０に調整し、３０分間保持した。スラリーｐＨを５．０に再調整後、基体マグネタイト重量に対して１．７５％（有効被覆量１．４５％）相当量の、予め加水分解処理を施したシラン化合物のｎ−デシルトリメトキシシラン液を添加し、同ｐＨ下で５時間撹拌保持した。撹拌機はＴＫホモミキサーを用いた。次にローラーポンプを用いて１００ｇ／Ｌの水酸化ナトリウム水溶液を２時間連続添加してｐＨ８．０に調整し１時間保持した。なお、処理の開始から終了までスラリーの温度は４０℃を維持した。処理終了スラリーはフィルタープレスを用いてろ過し、純水を使用してろ液の電気伝導度が２００μＳ／ｃｍ以下となるまで洗浄した。洗浄ケーキを９０℃で２時間乾燥後、続けて１３０℃で１時間熱処理を行った。熱処理物をＴＡＳＭ−１型サンプルミルを用いて粉砕した。
（実施例２）
基体粒子を表１に示すＢに変更し、シラン化合物のｎ−デシルトリメトキシシラン液の添加量を１．４４％とした以外は実施例１と同様の操作で疎水性磁性体酸化鉄粒子を得た。
（実施例３）
基体粒子を表１に示すＣに変更し、シラン化合物のｎ−デシルトリメトキシシラン液の添加量を１．８１％とした以外は実施例１と同様の操作で疎水性磁性体酸化鉄粒子を得た。
（実施例４）
基体粒子を表１に示すＤに変更し、シラン化合物のｎ−デシルトリメトキシシラン液の添加量を１．５５％とした以外は実施例１と同様の操作で疎水性磁性体酸化鉄粒子を得た。
（実施例５）
基体粒子を表１に示すＤに変更し、シラン化合物のｎ−デシルトリメトキシシランの添加量を１．１８％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例６）
基体粒子を表１に示すＤに変更し、シラン化合物をｎ−オクチルトリエトキシシランに変更し、その添加量を１．８７％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例７）
基体粒子を表１に示すＤに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を１．６４％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例８）
基体粒子を表１に示すＤに、シラン化合物をｎ−ヘキシルトリメトキシシランの原液に、添加量を１．６４％に、添加後の保持時間を２０時間にそれぞれ変更する以外は、実施例１と同様の方法で疎水性磁性酸化鉄粒子を得た。
（実施例９）
基体粒子を表１に示すＥに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を１．７４％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例１０）
基体粒子を表１に示すＦに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を１．７８％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例１１）
基体粒子を表１に示すＧに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を１．８６％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例１２）
基体粒子を表１に示すＨに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を１．４９％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例１３）
基体粒子を表１に示すＤに変更し、シラン化合物をｎ−ブチルトリメトキシシランに変更し、その添加量を２．３２％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例１４）
基体粒子を表１に示すＤに変更し、シラン化合物をｎ−ヘキサデシルトリメトキシシランに変更し、その添加量を０．９５％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例１５）
基体粒子を表１に示すＩに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を１．３４％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（実施例１６）
基体粒子を表１に示すＩに変更し、シラン化合物をｎ−オクチルトリエトキシシランに変更し、その添加量を１．２３％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（比較例１）
基体粒子を表１に示すＤに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を２．８８％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（比較例２）
基体粒子を表１に示すＤに変更し、シラン化合物をビニルトリメトキシシランに変更し、その添加量を２．０５％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（比較例３）
基体粒子を表１に示すＤに変更し、シラン化合物をγ−メタクリロキシプロピルトリメトキシシランに変更し、その添加量を１．５６％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（比較例４）
基体粒子を表１に示すＤに変更し、シラン化合物をｎ−ヘキシルトリメトキシシランに変更し、その添加量を０．７７％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
（比較例５）
基体粒子を表１に示すＤに変更し、シラン化合物をメチルトリメトキシシランに変更し、その添加量を２．６９％とした以外は実施例１と同様の操作で疎水性磁性酸化鉄粒子を得た。
Example 1
The substrate particles of Production Example A were used. The isoelectric point of the substrate was measured and found to be pH 8.0. The pH of the substrate slurry was adjusted to 5.0 and dispersed with a TK homomixer (6,000 rpm) for 30 minutes. The average particle size of the dispersed slurry was 0.72 μm. After adjusting the temperature of the dispersion slurry to 40 ° C. and the substrate concentration to 100 g / L, the slurry pH was adjusted to 5.0 with dilute hydrochloric acid of hydrochloric acid: water = 1: 9 (volume ratio) and held for 30 minutes. After re-adjusting the slurry pH to 5.0, n-decyltrimethoxysilane, a silane compound that has been pre-hydrolyzed, corresponding to 1.75% (effective coverage 1.45%) of the base magnetite weight The solution was added and stirred for 5 hours at the same pH. A TK homomixer was used as a stirrer. Next, a 100 g / L sodium hydroxide aqueous solution was continuously added for 2 hours using a roller pump, adjusted to pH 8.0, and held for 1 hour. The slurry temperature was maintained at 40 ° C. from the start to the end of the treatment. The treated slurry was filtered using a filter press, and washed with pure water until the filtrate had an electric conductivity of 200 μS / cm or less. The washed cake was dried at 90 ° C. for 2 hours and then heat-treated at 130 ° C. for 1 hour. The heat-treated product was pulverized using a TASM-1 type sample mill.
(Example 2)
The hydrophobic magnetic iron oxide particles were prepared in the same manner as in Example 1 except that the base particles were changed to B shown in Table 1 and the addition amount of the n-decyltrimethoxysilane solution of the silane compound was 1.44%. Obtained.
(Example 3)
The hydrophobic magnetic iron oxide particles were prepared in the same manner as in Example 1 except that the base particles were changed to C shown in Table 1 and the addition amount of the n-decyltrimethoxysilane solution of the silane compound was 1.81%. Got .
Example 4
The hydrophobic magnetic iron oxide particles were prepared in the same manner as in Example 1 except that the base particles were changed to D shown in Table 1 and the addition amount of the n-decyltrimethoxysilane solution of the silane compound was 1.55%. Obtained.
(Example 5)
Hydrophobic magnetic iron oxide particles were obtained in the same manner as in Example 1 except that the base particles were changed to D shown in Table 1 and the addition amount of n-decyltrimethoxysilane as a silane compound was 1.18%. .
(Example 6)
Hydrophobic magnetic iron oxide in the same manner as in Example 1 except that the base particle was changed to D shown in Table 1, the silane compound was changed to n-octyltriethoxysilane, and the addition amount was 1.87%. Particles were obtained.
(Example 7)
Hydrophobic magnetic iron oxide was changed in the same manner as in Example 1 except that the base particles were changed to D shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 1.64%. Particles were obtained.
(Example 8)
Example 1 except that the substrate particles are changed to D shown in Table 1, the silane compound is changed to an n-hexyltrimethoxysilane stock solution, the addition amount is changed to 1.64%, and the retention time after addition is changed to 20 hours. In the same manner, hydrophobic magnetic iron oxide particles were obtained.
Example 9
Hydrophobic magnetic iron oxide was changed in the same manner as in Example 1 except that the base particle was changed to E shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 1.74%. Particles were obtained.
(Example 10)
Hydrophobic magnetic iron oxide was prepared in the same manner as in Example 1 except that the base particles were changed to F shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 1.78%. Particles were obtained.
(Example 11)
Hydrophobic magnetic iron oxide was prepared in the same manner as in Example 1 except that the base particle was changed to G shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 1.86%. Particles were obtained.
(Example 12)
Hydrophobic magnetic iron oxide in the same manner as in Example 1 except that the base particles were changed to H shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 1.49%. Particles were obtained.
(Example 13)
Hydrophobic magnetic iron oxide in the same manner as in Example 1 except that the base particle was changed to D shown in Table 1, the silane compound was changed to n-butyltrimethoxysilane, and the addition amount was 2.32%. Particles were obtained.
(Example 14)
Hydrophobic magnetic oxidation was carried out in the same manner as in Example 1 except that the base particle was changed to D shown in Table 1, the silane compound was changed to n-hexadecyltrimethoxysilane, and the addition amount was 0.95%. Iron particles were obtained .
( Example 15 )
Hydrophobic magnetic iron oxide was prepared in the same manner as in Example 1 except that the base particles were changed to I shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 1.34%. Particles were obtained.
(Example 16 )
Hydrophobic magnetic iron oxide was changed in the same manner as in Example 1 except that the base particles were changed to I shown in Table 1, the silane compound was changed to n-octyltriethoxysilane, and the addition amount was 1.23%. Particles were obtained.
(Comparative Example 1)
Hydrophobic magnetic iron oxide was prepared in the same manner as in Example 1 except that the base particle was changed to D shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 2.88%. Particles were obtained.
(Comparative Example 2)
The hydrophobic magnetic iron oxide particles were changed in the same manner as in Example 1 except that the base particles were changed to D shown in Table 1, the silane compound was changed to vinyltrimethoxysilane, and the addition amount was 2.05%. Obtained.
(Comparative Example 3)
Hydrophobic magnetism is the same as in Example 1 except that the base particle is changed to D shown in Table 1, the silane compound is changed to γ-methacryloxypropyltrimethoxysilane, and the addition amount is 1.56%. Iron oxide particles were obtained.
(Comparative Example 4)
Hydrophobic magnetic iron oxide in the same manner as in Example 1 except that the base particle was changed to D shown in Table 1, the silane compound was changed to n-hexyltrimethoxysilane, and the addition amount was 0.77%. Particles were obtained.
(Comparative Example 5)
The hydrophobic magnetic iron oxide particles were changed in the same manner as in Example 1 except that the base particles were changed to D shown in Table 1, the silane compound was changed to methyltrimethoxysilane, and the addition amount was 2.69%. Obtained.
実施例および比較例で得られた疎水性磁性酸化鉄粒子の物性を表３に纏めた。なお、表３中の平均粒子径およびＳＤは、スチレン・ｎブチルアクリレート分散媒中の粒度分布の測定結果から求めた値である。 Table 3 summarizes the physical properties of the hydrophobic magnetic iron oxide particles obtained in the examples and comparative examples. In addition, the average particle diameter and SD in Table 3 are values obtained from the measurement results of the particle size distribution in the styrene / n-butyl acrylate dispersion medium.
表３から明らかな通り、実施例１〜１６の磁性酸化鉄粒子は、トルエン溶出率が３０％以下であり、概して優れた特性を持ち、特に実施例１〜１４の磁性酸化鉄粒子は、疎水化度、分散安定性、ならびに粒度分布が優れている。このように実施例の磁性酸化鉄粒子は、重合トナー用を始めとする静電複写磁性トナー用材料粉として好適であることが判る。 As is apparent from Table 3, the magnetic iron oxide particles of Examples 1 to 16 have a toluene elution rate of 30% or less and generally have excellent characteristics. In particular, the magnetic iron oxide particles of Examples 1 to 14 are hydrophobic. Excellent degree of conversion, dispersion stability, and particle size distribution. Thus, it can be seen that the magnetic iron oxide particles of the examples are suitable as material powders for electrostatic copying magnetic toners including those for polymerized toners.
比較例１の磁性酸化鉄粒子は被覆量が多いために、トルエン溶出率、分散安定性、ならびに粒度分布が劣る粒子であった。
比較例２および比較例３の磁性酸化鉄粒子はシラン化合物の種類が適切でないために、トルエン溶出率、疎水化度、分散安定性、ならびに粒度分布が劣る粒子であった。
[発明の効果]
以上説明したように、本発明の疎水性酸化鉄粒子は、基体粒子の表面に、特定のシラン化合物の適正量を均一に被覆することによって、トルエン溶出率、分散性、分散安定性及び撥水性に優れた酸化鉄粒子であり、特に重合トナー用を始めとする静電複写磁性トナー用材料粉として好適である。
Since the magnetic iron oxide particles of Comparative Example 1 had a large coating amount, the particles were inferior in toluene elution rate, dispersion stability, and particle size distribution.
The magnetic iron oxide particles of Comparative Example 2 and Comparative Example 3 were particles having poor toluene elution rate, hydrophobization degree, dispersion stability, and particle size distribution because the type of silane compound was not appropriate.
[The invention's effect]
As described above, the hydrophobic iron oxide particles of the present invention uniformly coat the surface of the substrate particles with an appropriate amount of a specific silane compound, so that the toluene elution rate, dispersibility, dispersion stability and water repellency are improved. In particular, the iron oxide particles are excellent as a material powder for electrostatic copying magnetic toners including those for polymerized toners.
Claims (4)
スチレン・ｎ−ブチルアクリレート分散媒中での粒度分布において、体積基準における累積平均粒子径：（ｄ５０％）が０．５〜１．５μｍであり、かつ、次式：
ＳＤ＝（ｄ８４％−ｄ１６％）／２
(なお、ｄ５０％とは粒子径の累積カーブが５０％となる点の粒子径を示し、ｄ８４％とは粒子径の累積カーブが８４％となる点の粒子径を示し、ｄ１６％ とは粒子径の累積カーブが１６％となる点の粒子径を示す)で示されるＳＤ値が０．５μｍ以下であることを特徴とする前記疎水性磁性酸化鉄粒子。 Hydrophobic magnetic iron oxide particles having magnetic iron oxide as a base particle and coated with a silane compound on the surface thereof, the elution rate of the silane compound into toluene is 30% or less, and the degree of hydrophobicity is 60 to 85%. The water content is 0.15 wt% or less, and the adsorbed water content is 0.05 wt% or less under high temperature and high humidity (30 ° C., relative humidity 81%),
In the particle size distribution in the styrene / n-butyl acrylate dispersion medium, the cumulative average particle size on a volume basis: (d50%) is 0.5 to 1.5 μm, and the following formula:
SD = (d84% -d16%) / 2
(Note that d50% indicates the particle diameter at which the cumulative curve of particle diameter becomes 50%, d84% indicates the particle diameter at the point where the cumulative curve of particle diameter reaches 84%, and d16% indicates the particle The hydrophobic magnetic iron oxide particles according to claim 1, wherein the SD value is 0.5 μm or less, which indicates a particle diameter at a point where the cumulative curve of diameter is 16%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005039145A JP4749733B2 (en) | 2004-02-18 | 2005-02-16 | Hydrophobic magnetic iron oxide particles |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004041566 | 2004-02-18 | ||
| JP2004041566 | 2004-02-18 | ||
| JP2005039145A JP4749733B2 (en) | 2004-02-18 | 2005-02-16 | Hydrophobic magnetic iron oxide particles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2005263619A JP2005263619A (en) | 2005-09-29 |
| JP4749733B2 true JP4749733B2 (en) | 2011-08-17 |
Family
ID=35088539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005039145A Active JP4749733B2 (en) | 2004-02-18 | 2005-02-16 | Hydrophobic magnetic iron oxide particles |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4749733B2 (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4324120B2 (en) * | 2005-02-18 | 2009-09-02 | キヤノン株式会社 | Magnetic toner |
| JP4877513B2 (en) * | 2007-03-14 | 2012-02-15 | 戸田工業株式会社 | Ferrite particle powder for bonded magnet, resin composition for bonded magnet, and molded body using them |
| JP5422904B2 (en) * | 2007-04-09 | 2014-02-19 | 戸田工業株式会社 | Hydrophobic magnetic iron oxide particle powder for magnetic toner and method for producing the same |
| CN101125685B (en) * | 2007-09-14 | 2010-05-19 | 东华大学 | Method for preparing lipophilic ferroferric oxide nano particles |
| JP5403214B2 (en) * | 2008-10-22 | 2014-01-29 | 戸田工業株式会社 | Surface-treated magnetic iron oxide particle powder, and black paint and rubber / resin composition using the surface-treated magnetic iron oxide particle powder |
| JP5403213B2 (en) * | 2008-10-22 | 2014-01-29 | 戸田工業株式会社 | Surface-treated magnetic iron oxide particle powder, and black paint and rubber / resin composition using the surface-treated magnetic iron oxide particle powder |
| JP5330794B2 (en) * | 2008-10-24 | 2013-10-30 | 三井金属鉱業株式会社 | Coated magnetite particles and method for producing the same |
| JP5330813B2 (en) * | 2008-11-21 | 2013-10-30 | 三井金属鉱業株式会社 | Hydrophobic magnetite particle powder |
| JP5400440B2 (en) * | 2009-03-19 | 2014-01-29 | 三井金属鉱業株式会社 | Magnetite particles |
| JP5473725B2 (en) * | 2009-04-15 | 2014-04-16 | キヤノン株式会社 | Magnetic toner |
| JP5606018B2 (en) * | 2009-07-21 | 2014-10-15 | 三井金属鉱業株式会社 | Coated magnetite particles |
| JP5715329B2 (en) * | 2009-07-21 | 2015-05-07 | 三井金属鉱業株式会社 | Coated magnetite particles |
| JP5773581B2 (en) * | 2010-05-28 | 2015-09-02 | 三井金属鉱業株式会社 | Method for producing coated magnetite particles |
| US8426094B2 (en) * | 2010-05-31 | 2013-04-23 | Canon Kabushiki Kaisha | Magnetic toner |
| JP5587065B2 (en) * | 2010-07-06 | 2014-09-10 | キヤノン株式会社 | Magnetic toner |
| US9551947B2 (en) | 2010-08-23 | 2017-01-24 | Canon Kabushiki Kaisha | Toner |
| JP6521239B2 (en) * | 2015-04-28 | 2019-05-29 | 戸田工業株式会社 | Hydrophobic magnetic iron oxide particle powder and method for producing the same |
| JP6418146B2 (en) * | 2015-12-16 | 2018-11-07 | 京セラドキュメントソリューションズ株式会社 | Positively chargeable toner and method for producing positively chargeable toner |
| CN115739574B (en) * | 2022-12-03 | 2023-06-30 | 西北工业大学 | Method and device for preparing wetting gradient surface and magnetic hydrophobic particles |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3450686B2 (en) * | 1996-12-26 | 2003-09-29 | キヤノン株式会社 | Magnetic toner for developing an electrostatic latent image, method for producing magnetic toner particles, and image forming method |
| JP4072384B2 (en) * | 2002-06-19 | 2008-04-09 | キヤノン株式会社 | Magnetic toner, image forming method using the toner, and process cartridge |
-
2005
- 2005-02-16 JP JP2005039145A patent/JP4749733B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2005263619A (en) | 2005-09-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4749733B2 (en) | Hydrophobic magnetic iron oxide particles | |
| US5843610A (en) | Magnetic particles for magentic toner and process for producing the same | |
| JP5422904B2 (en) | Hydrophobic magnetic iron oxide particle powder for magnetic toner and method for producing the same | |
| EP0826635B1 (en) | Magnetite particles and production process of the same | |
| JP2008230960A (en) | Black magnetic iron oxide particle | |
| JPH05213620A (en) | Magnetite particles and its production | |
| JP3551204B2 (en) | Black magnetic iron oxide particle powder | |
| US5759435A (en) | Magnetite particles and process for production thereof | |
| US5733471A (en) | Magnetite particles and process for production of the same | |
| JP3473003B2 (en) | Black magnetic iron oxide particle powder | |
| JP3427853B2 (en) | Granular magnetite particle powder and method for producing the same | |
| WO2020217982A1 (en) | Method for producing cobalt ferrite particles and cobalt ferrite particles produced by same | |
| JPH07257930A (en) | Spherical magnetite grain and production thereof | |
| JP4121273B2 (en) | Iron oxide particles | |
| JP5826453B2 (en) | Black magnetic iron oxide particle powder | |
| JP4448687B2 (en) | Black iron oxide particles, method for producing the same, electrophotographic toner using the same, and image forming method using the toner | |
| JP4183497B2 (en) | Black complex oxide particles and method for producing the same | |
| JPS6317222A (en) | Spherical magnetite particle powder and production thereof | |
| JP7229814B2 (en) | Electrophotographic pigment and method for producing the same | |
| JPH10279313A (en) | Magnetite particle and its production | |
| JP3437714B2 (en) | Magnetite particles and method for producing the same | |
| JP5773581B2 (en) | Method for producing coated magnetite particles | |
| JP3934852B2 (en) | Iron oxide particles | |
| JP2006062940A (en) | Magnetite particle | |
| JP2001312096A (en) | Magnetic particle powder for magnetic toner |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20080117 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20100818 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100823 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20101020 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20101124 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110218 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20110218 |
|
| A911 | Transfer to examiner for re-examination before appeal (zenchi) |
Free format text: JAPANESE INTERMEDIATE CODE: A911 Effective date: 20110314 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110419 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110518 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 4749733 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140527 Year of fee payment: 3 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |