JPS5854487B2 - Method for producing acicular magnetic iron oxide particle powder for magnetic recording materials - Google Patents
Method for producing acicular magnetic iron oxide particle powder for magnetic recording materialsInfo
- Publication number
- JPS5854487B2 JPS5854487B2 JP52104095A JP10409577A JPS5854487B2 JP S5854487 B2 JPS5854487 B2 JP S5854487B2 JP 52104095 A JP52104095 A JP 52104095A JP 10409577 A JP10409577 A JP 10409577A JP S5854487 B2 JPS5854487 B2 JP S5854487B2
- Authority
- JP
- Japan
- Prior art keywords
- acicular
- oxide particles
- particles
- ferric oxide
- hydrated ferric
- 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.)
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Description
【発明の詳細な説明】
本発明は磁気記録材料用針状磁性酸化鉄粒子粉末の製造
法に関するものであり、有機溶媒中での分散性、配向性
及び充填性の優れた針状磁性酸化鉄粒子粉末を得ること
を目的とするものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing acicular magnetic iron oxide particles for magnetic recording materials. The purpose is to obtain particulate powder.
現在、磁気記録材料用として汎用されている針状磁性酸
化鉄粉末は、一般に、第一鉄塩溶液とアルカリとの湿式
反応によって得られる針状含水酸化第二鉄を出発物とし
、これを空気中３００℃附近で加熱脱水してα一酸化第
二鉄とし、次いで水素気流中３００〜４００℃で還元し
て針状マグネタイトとする。Acicular magnetic iron oxide powder, which is currently widely used for magnetic recording materials, generally starts with acicular hydrated ferric oxide obtained by a wet reaction between a ferrous salt solution and an alkali, and then air It is heated and dehydrated at around 300°C to form alpha ferric monoxide, and then reduced at 300 to 400°C in a hydrogen stream to form acicular magnetite.
また必要により針状マグネタイトを２００〜３００℃で
再酸化して針状マグネタイトとすることにより得られて
いるものである。Further, if necessary, the acicular magnetite is obtained by reoxidizing the acicular magnetite at 200 to 300°C to obtain acicular magnetite.
尚、上記の「湿式反応」とは、第一鉄塩溶液にアルカリ
を添加して水酸化第一鉄を生成し、所定のｐｎ、６度で
空気を吹込み酸化して針状含水酸化第二鉄とする周知の
ものである。The above-mentioned "wet reaction" refers to adding an alkali to a ferrous salt solution to produce ferrous hydroxide, and oxidizing it by blowing air at a predetermined pn and 6 degrees to form acicular hydrated ferrous hydroxide. This is a well-known type of iron.
しかしながら、上述した方法によって得られる針状マグ
ネタイト粒子あるいは針状マグヘマイト粒子は磁性塗料
を得る為有機溶媒中に分散させるに際して非常に多くの
時間及び労力を必要とするものである。However, the acicular magnetite particles or acicular maghemite particles obtained by the above-mentioned method require a great deal of time and effort to disperse in an organic solvent to obtain a magnetic coating material.
何故ならば、酸化鉄粒子自体が本来親水性であるという
性質を有しているから有機溶媒中には必然的に分散しに
くいのに加えて、上記の各磁性酸化鉄粒子は針状であり
、互に強固にからみ合っていること、あるいは熱処理過
程を経ることによって焼結して凝集していることに配回
して、このような針状の磁性酸化鉄粒子を有機溶媒中に
均一に分散させるのは非常な困難を要するのである。This is because the iron oxide particles themselves are inherently hydrophilic and are naturally difficult to disperse in organic solvents, and the magnetic iron oxide particles mentioned above are acicular in shape. These acicular magnetic iron oxide particles are uniformly dispersed in an organic solvent by being tightly intertwined with each other, or by being sintered and aggregated through a heat treatment process. It is extremely difficult to do so.
また、高性能の磁気記録材料、即ち各種の磁気テープ、
磁気ディスク等を得る為には磁性塗膜中の磁性酸化鉄粒
子を配向させ、あるいは該磁性酸化鉄粒子の充填率を高
くする必要があるが、前述したように粒子相互がからみ
合い、または焼結等により凝集している上記の各針状磁
性酸化鉄粒子は、そのままでは満足できる配向度及び充
填率は得られない。In addition, high-performance magnetic recording materials, namely various magnetic tapes,
In order to obtain magnetic disks, etc., it is necessary to orient the magnetic iron oxide particles in the magnetic coating film or increase the filling rate of the magnetic iron oxide particles. The above-mentioned acicular magnetic iron oxide particles, which are aggregated due to coalescence, etc., cannot obtain a satisfactory degree of orientation and filling rate if left as they are.
この為当業界では、従来、上記の各針状磁性酸化鉄粒子
を有機溶媒中に分散させるに際して（転界面活性剤を添
加して親油性化すると同時に、強力な混合機を長時間用
いて強制的に分散させているのである。For this reason, in the industry, conventionally, when dispersing the above-mentioned acicular magnetic iron oxide particles in an organic solvent (adding a surfactant to make them lipophilic), at the same time, a powerful mixer was used for a long period of time to force the particles to disperse. This means that they are dispersed.
しかし、界面活性剤を添加することにより上記の各針状
磁性酸化鉄粒子をいくらか親油性とすることは可能とな
るが、上記の各針状磁性酸化鉄粒子は焼結等により凝集
しているものであり、添加する界面活性剤は凝集を解き
ほぐす機能は有していない。However, it is possible to make each of the above acicular magnetic iron oxide particles somewhat lipophilic by adding a surfactant, but each of the above acicular magnetic iron oxide particles is agglomerated by sintering etc. The added surfactant does not have the function of loosening aggregation.
従って、上記の各針状磁性酸化鉄粒子の凝集を解きほぐ
そうとすれば、上述した強力な混合機あるいは粉砕機等
の機械的な力にたよらなければならない。Therefore, in order to loosen the agglomeration of the above-mentioned acicular magnetic iron oxide particles, it is necessary to rely on mechanical force such as the above-mentioned strong mixer or crusher.
機械的な力によって焼結等による凝集を解きほぐし、分
散させようとした場合には、必然的に針状磁性酸化鉄粒
子が傷つけられ、あるいは砕かれて針状磁性酸化鉄粒子
の命とも言うべき針状性が悪化してしまうのである。If mechanical force is used to loosen and disperse agglomerations caused by sintering, etc., the acicular magnetic iron oxide particles will inevitably be damaged or crushed, resulting in the life of the acicular magnetic iron oxide particles. This results in worsening of the acicularity.
本発明者は、上記したことから針状磁性酸化鉄粒子を用
い磁性塗料を得ようとした場合に、その分散性を改善す
る為には、単に界面活性剤を添加して針状磁性酸化鉄粒
子を親油性とするだけでは不充分であることを知り、分
散性の優れたものとする為には焼結等による凝集のない
針状磁性酸化鉄粒子を得、更に該粒子に界面活性剤によ
る被覆を施せば、分散性に優れ、更に配向性及び充填性
の優れた針状磁性酸化鉄粒子になるであろうと考えたの
である。Based on the above, the present inventor has discovered that when attempting to obtain a magnetic paint using acicular magnetic iron oxide particles, in order to improve its dispersibility, it is necessary to simply add a surfactant to the acicular magnetic iron oxide particles. Knowing that it is not enough to make particles lipophilic, in order to have excellent dispersibility, we obtain acicular magnetic iron oxide particles that do not aggregate by sintering, etc., and further add a surfactant to the particles. It was thought that if coated with this material, acicular magnetic iron oxide particles with excellent dispersibility, orientation, and filling properties would be obtained.
本発明者は、針状磁性酸化鉄粒子の焼結等による凝集を
なくする為に、磁気記録材料用に使用される針状磁性酸
化鉄粒子の製造過程、あるいは粒子相互間にからみ合い
、凝集等が起る時期及びその原因について永年に亘り鋭
意研究を重ねて来た。In order to eliminate the agglomeration of acicular magnetic iron oxide particles due to sintering, etc., the present inventor has developed a process for producing acicular magnetic iron oxide particles used for magnetic recording materials, or the entanglement and aggregation of acicular magnetic iron oxide particles between particles. For many years, we have conducted intensive research into the timing and causes of such occurrences.
そして、針状磁性酸化鉄粒子を得る為の出発物である針
状含水酸化第二鉄粒子を湿式反応により生成させる場合
に＆Ｌ該針状含水酸化第二鉄粒子は、湿式反応時に、反
応母液中の結晶成長の過程でかなり強固にからみ合い、
結合し合った粒子群を形成しており、更にからみ合い、
結合し合った粒子群中には針状含水酸化第二鉄粒子の生
成反応による副生物（例えば硫酸ナトリウム）や反応に
寄与しなかった余分のアルカリあるいは酸根等を含有し
ている。When acicular hydrated ferric oxide particles, which are the starting material for obtaining acicular magnetic iron oxide particles, are produced by a wet reaction, the acicular hydrated ferric oxide particles are formed in the reaction mother liquor during the wet reaction. In the process of crystal growth inside, they are intertwined quite tightly,
They form a group of particles that are connected to each other, and are further entangled,
The bonded particles contain by-products (for example, sodium sulfate) from the reaction for producing acicular hydrated ferric oxide particles and excess alkali or acid radicals that did not contribute to the reaction.
このように粒子群中に含有されテイル副生物あるいはア
ルカリ等は通常行われている水洗では完全には除去し得
す、後の脱水、還元、酸化等の加熱処理により、該副生
物等を中心にしてからみ合い、結合部分において粒子の
焼結が起り、前述した通り分散しにくい磁性酸化鉄にな
ってしまうのである。In this way, the tail by-products or alkalis contained in the particle group cannot be completely removed by normal water washing, but the by-products, etc. can be removed by subsequent heat treatments such as dehydration, reduction, and oxidation. As a result, the particles become entangled and sinter at the bonded portion, resulting in magnetic iron oxide that is difficult to disperse as described above.
そこで本発明者は、針状含水酸化第二鉄粒子の結晶成長
過程において発生する粒子のからみ合い、結合等を脱水
、還元、酸化等の加熱処理を施す前に解きほぐし、更に
該からみ合い等により形成された粒子群中の副生物等を
完全に除去すれば、加熱処理による粒子の焼結を最少限
にすることができると考えたのである。Therefore, the present inventor has devised a method for disentangling the entanglements, bonds, etc. of particles that occur during the crystal growth process of acicular hydrated ferric oxide particles before applying heat treatments such as dehydration, reduction, and oxidation, and further improving the entanglements, etc. They believed that by completely removing by-products and the like in the formed particles, sintering of the particles due to heat treatment could be minimized.
針状含水酸化第二鉄粒子のからみ合い等を解きほぐす手
段は種々考えられる。Various means can be considered for disentangling the acicular hydrated ferric oxide particles.
しかし、例えば粉砕機等の機械的手段を用いて解きほぐ
そうとすると、針状含水酸化第二鉄粒子のからみ合い等
が解きほぐされると同時に粒子自体の破壊が必然的に起
こり、針状性の劣化等の悪影響が発生する。However, if an attempt is made to disentangle the acicular hydrated ferric oxide particles using mechanical means such as a crusher, the particles themselves will inevitably be destroyed at the same time as the entanglements of the acicular hydrated ferric oxide particles are disentangled. Adverse effects such as deterioration occur.
そこで本発明・者は、上記機械的手段に替えて分散剤に
よる化学的手段により針状含水酸化第二鉄粒子のからみ
合い等を解きほぐそうとしたのである。Therefore, the inventors of the present invention attempted to disentangle the acicular hydrated ferric oxide particles by chemical means using a dispersant instead of the mechanical means described above.
分散剤として使用可能な物質は種々存在するが、本発明
の終局の目的が磁性酸化鉄粒子のからみ合い、凝集等を
無くしようとするものであるから、それに最も有効な分
散剤として本発明者はリン酸塩を採用した。There are various substances that can be used as dispersants, but since the ultimate purpose of the present invention is to eliminate entanglement, aggregation, etc. of magnetic iron oxide particles, the present inventor has selected the most effective dispersant for this purpose. adopted phosphate.
リン酸塩は例えば塗料業界において各種の塗料を製造す
るに際して顔料をバインダー中に均一に分散させる為に
しばしば使用されている様に優れた分散剤としての機能
を有していることは良く知られている。It is well known that phosphates have an excellent function as a dispersant, as they are often used in the paint industry to uniformly disperse pigments in binders when manufacturing various paints. ing.
一方、酸化鉄業界においては、磁性酸化鉄を製造するに
際して焼結防止剤として添加使用されているものである
。On the other hand, in the iron oxide industry, it is added as an anti-sintering agent when producing magnetic iron oxide.
これらのことから、リン酸塩を使用すれば、上記分散剤
としての機能により針状含水酸化第二鉄粒子のからみ合
い等を解きほぐすと同時に、次の脱水還元、酸化等の加
熱処理工程において焼結防止機能が働くことを期待した
からである。Based on these facts, if phosphate is used, it can disentangle the needle-shaped hydrated ferric oxide particles by its function as a dispersant, and at the same time, it can be used as a dispersant to disentangle the acicular hydrated ferric oxide particles, and at the same time, it can be used as a dispersant. This is because I expected the anti-fog function to work.
次いで本発明者は、上記リン酸塩を使用する場合の最適
条件を決定する為に数多くの実験、検討を重ねた結果、
針状含水酸化第二鉄の生成反応の完了している反応母液
中にリン酸塩を添加すると、針状含水酸化第二鉄の結晶
成長過程において発生する粒子のからみ合い、結合等を
極めて有効に解きほぐすことが可能となることを見い出
し、本発明を完成するに至ったのである。Next, as a result of numerous experiments and studies in order to determine the optimal conditions for using the above-mentioned phosphate, the present inventor found that
When phosphate is added to the reaction mother liquor in which the production reaction of acicular hydrated ferric oxide has been completed, it is extremely effective in preventing the entanglement and bonding of particles that occur during the crystal growth process of acicular hydrated ferric oxide. They have discovered that it is possible to unravel this, and have completed the present invention.
即ち本発明は、第一鉄塩溶液とアルカリとの湿式反応に
より針状含水酸化第二鉄粒子を生成させ、該生成反応が
完了している反応母液中に、含水酸化第二鉄に対し０．
１〜１５重量％（ＰＯ３に換算）のリン酸塩を添加し、
攪拌した後、針状含水酸化第二鉄粒子をＰ別、水洗、乾
燥し、次いで常法により加熱脱水、還元をして針状マグ
ネタイト粒子とするか、更に酸化して針状マグヘマイト
粒子とすることを特徴とする磁気記録材料用針状磁性酸
化鉄粒子粉末の製造法、及び、上記針状マグネタイト粒
子又は針状マグヘマイト粒子を０．Ｏ１〜２重量多の界
面活性剤により被覆することを特徴とする磁気記録材料
用針状磁性酸化鉄粒子粉末の製造法である。That is, the present invention produces acicular hydrated ferric oxide particles through a wet reaction between a ferrous salt solution and an alkali, and in the reaction mother liquor in which the production reaction has been completed, 0% of the hydrated ferric oxide is added. ．．
Adding 1 to 15% by weight (calculated as PO3) of phosphate;
After stirring, the acicular hydrated ferric oxide particles are separated by P, washed with water, dried, and then heated and dehydrated and reduced by a conventional method to form acicular magnetite particles, or further oxidized to form acicular maghemite particles. A method for producing an acicular magnetic iron oxide particle powder for a magnetic recording material, characterized in that the acicular magnetite particles or acicular maghemite particles are 0. This is a method for producing acicular magnetic iron oxide particles for magnetic recording materials, which is characterized in that the powder is coated with a surfactant having a weight of 1 to 2 O.
次に本発明の詳細について説明する。Next, details of the present invention will be explained.
先ず、本発明に使用できる針状含水酸化第二鉄粒子の製
造法は湿式法であればいかなる方法でも良い。First, the acicular hydrated ferric oxide particles that can be used in the present invention may be produced by any wet method.
即ち、針状含水酸化第二鉄粒子の製造法は大別して酸性
領域の反応とアルカリ領域の反応であるが、いずれの場
合にも生成する針状含水酸化第二鉄粒子のからみ合いあ
るいは凝集等は生ずるのであり、換言すれば、本発明の
効果もまったく同様に発揮させることができるのである
。In other words, the method for producing acicular hydrated ferric oxide particles can be roughly divided into reactions in an acidic region and reactions in an alkaline region, but in either case, entanglement or aggregation of the acicular hydrated ferric oxide particles produced. In other words, the effects of the present invention can be achieved in exactly the same way.
次に、本発明で最も重要なリン酸塩の添加について説明
すると、リン酸塩の添加は、針状含水酸化第二鉄粒子の
生成反応が完了している反応母液に対して行わなければ
ならない。Next, to explain the most important addition of phosphate in the present invention, the addition of phosphate must be performed to the reaction mother liquor in which the production reaction of acicular hydrated ferric oxide particles has been completed. .
即ち、酸化鉄粒子の生成工程として一般に行われている
反応母液と針状含水酸化第二鉄粒子とのＰ別分離あるい
は針状含水酸化第二鉄粒子の水洗工程の前に行わなけれ
ばならないのである。In other words, this must be carried out before the step of separating the reaction mother liquor and acicular hydrated ferric oxide particles by P or washing the acicular hydrated ferric oxide particles with water, which are generally performed as steps for producing iron oxide particles. be.
何故ならば、既に詳述した通り、針状含水酸化第二鉄粒
子は、該含水酸化第二鉄粒子の結晶成長の段階で既にか
らみ合い、結合した粒子群を形成しており、反応母液と
の１別分離、あるいは水洗工程を経てペースト状態とす
る如く、含水酸化第二鉄粒子の存在する液の濃度が増す
と、リン酸塩を添加しても針状含水酸化第二鉄粒子を一
個一個バラバラの状態にほぐすことは不可能となり、こ
の結果、当然最終目的物であるマグネタイトあるいはマ
グネタイトにまでその影響が及ぶことになるからである
。This is because, as already explained in detail, the acicular hydrated ferric oxide particles are already entangled and form a bonded particle group at the stage of crystal growth of the hydrated ferric oxide particles, and the acicular hydrated ferric oxide particles are already entangled to form a bonded particle group. When the concentration of a solution containing hydrated ferric oxide particles increases, such as by separate separation of ferric oxide particles or by washing with water to form a paste, even if phosphate is added, only one acicular hydrated ferric oxide particle can be produced. This is because it becomes impossible to disintegrate into individual pieces, and as a result, the influence naturally extends to the final target, magnetite or magnetite.
更に、もし含水酸化第二鉄粒子の生成反応の完了前、即
ち生成反応前あるいは生成反応中にリン酸塩を添加した
場合にｌｌ−４粒子のからみ合いを解きほぐし、分散性
の良い粒子を得るという効果は得られないのである。Furthermore, if phosphate is added before the production reaction of hydrous ferric oxide particles is completed, that is, before or during the production reaction, the entanglement of the ll-4 particles is disentangled to obtain particles with good dispersibility. That effect cannot be obtained.
この点について詳述すれば、含水酸化第二鉄粒子の生成
前あるいは生成中にリン酸塩を添加する技術としては、
例えば特開昭４７−４２３９６号公報あるいは特開昭５
０−５７９９６号公報が存在するが、これらの公報記載
の発明により含水酸化第二鉄粒子の生成前あるいは生成
中にリン酸塩を添加した場合には本発明の効果、即ち粒
子のからみ合いを解きほぐし、磁性酸化鉄粒子とした際
の分散性等を向上させる°効果を得ることはできないの
である。To elaborate on this point, the techniques for adding phosphate before or during the production of hydrous ferric oxide particles include:
For example, JP-A No. 47-42396 or JP-A No. 5
No. 0-57996 exists, but when phosphate is added before or during the formation of hydrous ferric oxide particles according to the inventions described in these publications, the effect of the present invention, that is, the entanglement of particles can be improved. It is not possible to obtain the effect of improving dispersibility etc. when disentangled and made into magnetic iron oxide particles.
このことを以下に実験例を差げて説明する。This will be explained below using an experimental example.
以下の実験例は、本発明の実験例１の含水酸化第二鉄粒
子生成の条件下において、前記した特開昭４７−４２３
９６号公報記載の発明で示されているリン酸塩の添加時
期に合わせて（含水酸化第二鉄粒子の生成中あるいは生
成前）リン酸塩な添加して含水酸化第二鉄粒子を生成し
、本発明の実施例１と同一の条件でマグネタイトとした
後、各種特性を測定したものである。The following experimental example was carried out under the conditions of generating hydrous ferric oxide particles in Experimental Example 1 of the present invention, as described in Japanese Patent Application Laid-Open No. 47-423.
Hydrous ferric oxide particles are generated by adding phosphate according to the timing of addition of phosphate (during or before generation of hydrated ferric oxide particles) as shown in the invention described in Publication No. 96. After making magnetite under the same conditions as in Example 1 of the present invention, various properties were measured.
実験例 ｌ
Ｆｅ２す０．４５ ｍａｄ ／ 、 ノ硫酸第−鉄水溶
液２１に２．２５−ＮのＮａＯＨ水溶液１１を加え、更
にメタリン酸ナトリウム０．４０ｆｆを添加した後、溶
液温度４０℃で空気酸化して含水酸化第二鉄粒子を生成
させた。Experimental example l Fe2sulphate 0.45 mad/, 2.25-N NaOH aqueous solution 11 was added to ferrous sulfate aqueous solution 21, and after adding sodium metaphosphate 0.40ff, air oxidation was carried out at a solution temperature of 40°C. to produce hydrous ferric oxide particles.
上記反応母液から水洗、１別、乾燥して得た含水酸化第
二鉄粒子のＢＥＴ法による比表面積は４０ｒｒｒ／ｙで
あった。The specific surface area of the hydrous ferric oxide particles obtained from the above reaction mother liquor by washing with water, separating and drying was 40 rrr/y by the BET method.
上記含水酸化第二鉄粒子粉末を空気中３００℃にて加熱
脱水し、引き続き水素気流中３３０℃にて還元して針状
マグネタイト粒子粉末とした後、空気中２５０℃にて酸
化することにより針状マグヘマイト粒子粉末とした。The above-mentioned hydrated ferric oxide particles were dehydrated by heating at 300°C in air, and then reduced at 330°C in a hydrogen stream to obtain acicular magnetite particles, which were then oxidized in air at 250°C to form needles. maghemite particles powder.
このようにして得た針状マグヘマイト粒子粉末の磁気特
性は、抗磁力Ｈｃ：４２５０ｅ、飽和磁化σｇ ： ６
９．５ ｅｍｕ／ ｔであり、粉体特性は、吸油量：８
０ｍ／１０（１，カサ密度： ０．２０ ｆ／ｄであっ
た。The magnetic properties of the acicular maghemite particles thus obtained are as follows: coercive force Hc: 4250e, saturation magnetization σg: 6
9.5 emu/t, and the powder properties are oil absorption: 8
0 m/10 (1, bulk density: 0.20 f/d).
更に上記針状マグヘマイト粒子粉末を用いて実施例１と
同様にして磁性塗料並びに磁気テープを作成し、磁気特
性を測定した結果、抗磁力ＨＣ：３０００ｅ、残留磁束
密度Ｂｒ二１２５０Ｇａｕｓｓ角形Ｂｒ／Ｂｍ：ｏ、６
８であった。Furthermore, a magnetic paint and a magnetic tape were prepared in the same manner as in Example 1 using the acicular maghemite particle powder, and the magnetic properties were measured. As a result, coercive force HC: 3000e, residual magnetic flux density Br2 1250 Gauss square Br/Bm: o, 6
It was 8.
実験例 ２
Ｆｅ” ０．４５ｍｏｌ／ ｉｔの硫酸第一鉄水溶液２
１に２．２５−ＮのＮａＯＨ水溶液１１を加え、溶液温
度４０℃で空気酸化して含水酸化第二鉄の生成反応を行
った。Experimental example 2 Ferrous sulfate aqueous solution containing 0.45 mol/it of Fe” 2
A 2.25-N NaOH aqueous solution 11 was added to 1 and air oxidized at a solution temperature of 40°C to perform a reaction for producing hydrous ferric oxide.
溶液中のＦｅ”十濃度を確認しながら反応をつづけ、Ｆ
ｅ”十濃度が０．０４ｍｏｌ／ｌとなった時点で０．４
Ｏｆのメタリン酸ナトリウムを溶かした溶液を添加し、
Ｆｅ２＋がなくなるまで反応を継続した後、水洗、Ｐ別
、乾燥して含水酸化第二鉄粒子粉末とした。Continuing the reaction while checking the concentration of Fe in the solution,
e”0.4 when the concentration reaches 0.04 mol/l
Add a solution of sodium metaphosphate of
After the reaction was continued until Fe2+ disappeared, it was washed with water, separated from P, and dried to obtain a hydrous ferric oxide particle powder.
得られた含水酸化第二鉄粒子粉末は、ＢＥＴ法による比
表面積３６Ｊ／ｒであった。The obtained hydrous ferric oxide particles had a specific surface area of 36 J/r by the BET method.
上記含水酸化第二鉄粒子粉末を実験例１と同様にして針
状マグヘマイト粒子粉末とした。The above hydrous ferric oxide particles were made into acicular maghemite particles in the same manner as in Experimental Example 1.
得られた針状マグヘマイト粒子粉末の磁気特性は抗磁力
Ｈｃ：’４１００ｅ、飽和磁化ａ Ｂ ： ７３．Ｏｅ
ｍｕ／ ｔであり、粉体特性＆転成油量：６ｏｍｇ／１
ｏｏｒ、カサ密度＝０．２６ｆ／−であった。The magnetic properties of the obtained acicular maghemite particles were as follows: coercive force Hc: '4100e, saturation magnetization aB: 73. Oe
mu/t, powder properties & converted oil amount: 6omg/1
oor, bulk density=0.26f/-.
次いで、上記針状マグヘマイト粒子粉末を用いて実施例
１と同様にして磁性塗料並びに磁気テープを作成し、磁
気特性を測定した結果、抗磁力Ｈｃ：３２００ｅ、残留
磁束密度Ｂｒ：１３００Ｇａｕｓｓ 、角型Ｂ ｒ ／
Ｂｍ ： ０．７３であった。Next, a magnetic paint and a magnetic tape were prepared in the same manner as in Example 1 using the acicular maghemite particle powder, and the magnetic properties were measured. As a result, coercive force Hc: 3200e, residual magnetic flux density Br: 1300 Gauss, square shape B r/
Bm: 0.73.
上記実験例から明らかな通り、含水酸化第二鉄粒子の生
成中又は生成前にリン酸塩を添加する方法（特開昭４７
−４２３９６号公報記載の発明の方法）により含水酸化
第二鉄粒子を生成した場合のリン酸塩の添加効果は粒子
の大きさに最も大きく影響を示す（ＢＥＴ法による比表
面積が大となる。As is clear from the above experimental examples, a method of adding phosphate during or before the formation of hydrous ferric oxide particles (Japanese Patent Laid-Open No. 47
When hydrous ferric oxide particles are produced by the method of the invention described in Publication No. 42396), the effect of adding phosphate has the greatest influence on the size of the particles (the specific surface area by the BET method becomes large).
）のである。このような含水酸化第二鉄粒子を用いて磁
性酸化鉄粒子粉末を得、更に磁性塗料並びに磁気テープ
とした場合においても分散性はあまり向上せず、また角
型はリン酸をまったく使用しない場合よりも低い値を示
すのである。). Even when such hydrous ferric oxide particles are used to obtain magnetic iron oxide particle powder and used as magnetic paint or magnetic tape, the dispersibility does not improve much, and the square shape does not use phosphoric acid at all. It shows a value lower than .
以上説明したことから明らかなように、リン酸塩の添加
時期は含水酸化第二鉄粒子の生成反応が完全に終了した
後でなげればならないのである。As is clear from the above explanation, the phosphate should be added after the reaction for producing hydrated ferric oxide particles is completely completed.
次に、添加するリン酸塩の量について述べると、ＰＯ３
に換算して０．１〜１５重量袈の範囲でなげればならな
い。Next, regarding the amount of phosphate to be added, PO3
It must be thrown within the range of 0.1 to 15 weights.
０．１重量饅以下の場合には添加による効果が充分発揮
できない。If the amount is less than 0.1% by weight, the effect of addition cannot be sufficiently exerted.
上記リン酸塩の添加による針状含水酸化第二鉄粒子のか
らみ合い等を解きほぐす効果は、該針状含水酸化第二鉄
粒子の存在する反応母液の性質、特にｐＨ値によって異
り、特に反応母液のｐＨ値が３〜４程度の場合に最も顕
著な効果を現わす。The effect of disentangling the acicular hydrated ferric oxide particles due to the addition of the phosphate salt varies depending on the properties of the reaction mother liquor in which the acicular hydrated ferric oxide particles exist, especially the pH value. The most remarkable effect appears when the pH value of the mother liquor is about 3 to 4.
従って、リン酸塩の添加量もこの様なｐＨ値のとき少量
ですむので好ましい。Therefore, it is preferable that the amount of phosphate added is small at such a pH value.
尚、反応母液がアルカリ性の場合には、該アルカリ性反
応母液に直接リン酸塩を添加することもできるが、適当
なる酸、例えば硫酸等を添加してｐＨ値を３〜４に調整
した後リン酸塩を添加すれば、添加量について有利な条
件となる。In addition, when the reaction mother liquor is alkaline, phosphate can be added directly to the alkaline reaction mother liquor, but after adjusting the pH value to 3 to 4 by adding a suitable acid, such as sulfuric acid, the phosphate can be added directly to the alkaline reaction mother liquor. Addition of an acid salt provides advantageous conditions regarding the amount of addition.
勿論、硫酸等の添加によるｐＨ値の調整を行うことなく
リン酸塩を多量に添加してもよいが、リン酸塩の大量使
用は排水処理や経済的見地等から望ましくないので１５
重量多以下とすべきである。Of course, a large amount of phosphate may be added without adjusting the pH value by adding sulfuric acid, etc., but since the use of large amounts of phosphate is undesirable from the viewpoint of wastewater treatment and economics, etc.
It should be less than heavy.
また、リン酸塩の添加方法としては、粉末等をそのまま
反応母液中に添加することもできるし、水に溶解した後
添加するという手段をとっても良い。Further, as a method for adding the phosphate, a powder or the like can be directly added to the reaction mother liquor, or it can be added after being dissolved in water.
尚、添加するリン酸塩としては、ヘキサメタリン酸ナト
リウム、ピロリン酸ナトリウム、メタリン酸ナトリウム
等が挙げられる。In addition, examples of the phosphate to be added include sodium hexametaphosphate, sodium pyrophosphate, and sodium metaphosphate.
次に、リン酸塩の添加によりからみ合い等を解きほぐし
た針状含水酸化第二鉄粒子を針状磁性酸化鉄粒子とする
手段について説明する。Next, a method for forming acicular magnetic iron oxide particles from acicular hydrated ferric oxide particles that have been disentangled by adding a phosphate will be described.
上述した如く、反応母液中においてからみ合い等を解き
ほぐした針状含水酸化第二鉄粒子に転通常の方法により
得られる針状含水酸化第二鉄粒子を針状磁性酸化鉄粒子
とする際に採られる通常の手段を用いればよく、何ら特
別の手段は必要としない。As mentioned above, when the acicular hydrated ferric oxide particles obtained by a conventional method are converted into acicular hydrated ferric oxide particles which are disentangled in the reaction mother liquor, the acicular magnetic iron oxide particles are converted into acicular magnetic iron oxide particles. It is sufficient to use any ordinary means available, and no special means are required.
即ち脱水においては空気中３００℃附近、還元において
は水素等の還元性雰囲気中３００〜４００℃、酸化にお
いては空気中２００〜３００℃に加熱すればよい。That is, for dehydration it may be heated in air at around 300°C, for reduction it may be heated to 300 to 400°C in a reducing atmosphere such as hydrogen, and for oxidation it may be heated to 200 to 300°C in air.
次に、針状磁性酸化鉄粒子を界面活性剤で被覆する方法
について説明する。Next, a method for coating acicular magnetic iron oxide particles with a surfactant will be described.
針状磁性酸化鉄粒子を界面活性剤で被覆するには以下に
示す二つの手段が考えられる。The following two methods can be considered for coating acicular magnetic iron oxide particles with a surfactant.
即ちその一つは、針状磁性酸化鉄粒子を水中に懸濁させ
、該懸濁液に所定量の界面活性剤を添力用し、攪拌して
針状磁性酸化鉄粒子表面に界面活性剤を均一に吸着させ
、被覆層を形成させる方法である。In one method, acicular magnetic iron oxide particles are suspended in water, a predetermined amount of surfactant is added to the suspension, and the surfactant is applied to the surface of the acicular magnetic iron oxide particles by stirring. This is a method of uniformly adsorbing and forming a coating layer.
今一つは、針状磁性酸化鉄粒子に、水に溶解させた所定
量の界面活性剤を噴霧し、混合して被覆層を形成する方
法である。Another method is to spray a predetermined amount of a surfactant dissolved in water onto acicular magnetic iron oxide particles and mix them to form a coating layer.
上記いずれの方法を用いた場合でも界面活性剤の量は針
状磁性酸化鉄粒子に対し０．０１〜２重量φでよい。No matter which method is used, the amount of surfactant may be 0.01 to 2 weight φ relative to the acicular magnetic iron oxide particles.
０．０１重重量風下の場合には界面活性剤の被覆による
効果が顕著に現われない。In the case of 0.01 weight downwind, the effect of surfactant coating is not noticeable.
一方、２重量多以上の場合には、後に針状磁性酸化鉄粒
子を用いて磁性塗料化し、更に磁気テープ等の磁気記録
材料としたときに界面活性剤が塗膜表面に浸み出し、各
種の特性に悪影響を及ぼす為好ましくない。On the other hand, if the weight is 2 or more, when the acicular magnetic iron oxide particles are later made into a magnetic coating material and further used as a magnetic recording material such as a magnetic tape, the surfactant leaches out onto the coating surface, resulting in various It is undesirable because it has a negative effect on the characteristics of
尚、界面活性剤としては種々のものが使用できるが、例
えばリン酸エステル等が好適である。Note that various surfactants can be used, and for example, phosphoric acid esters are suitable.
以上詳細に亘り述べて来た本発明の効果について述べる
と以下の通りである。The effects of the present invention, which have been described in detail above, are as follows.
本発明を施行することにより、針状含水酸化第二鉄粒子
はからみ合いあるいは凝集等のほとんどない粒子となる
から、該粒子を反応母液から１別するに際してはその操
作が容易となる。By carrying out the present invention, the acicular hydrated ferric oxide particles become particles with almost no entanglement or aggregation, so that the separation of the particles from the reaction mother liquor becomes easy.
また針状含水酸化第二鉄粒子の水洗過程も、従来の針状
含水酸化第二鉄のようにからみ合った粒子群を形成して
いるものに比べて極めて効率よく行われる。Furthermore, the washing process of the acicular hydrated ferric oxide particles is extremely efficient compared to conventional acicular hydrated ferric oxide particles that form entangled particle groups.
更に針状含水酸化第二鉄粒子にからみ合い等が無いこと
により、脱水、還元、酸化の各工程の加熱処理における
焼結等による凝集は極めて起りにくく、マグネタイトあ
るいはマグヘマイトとした後も含水酸化第二鉄と同様−
個一個の粒子がバラバラの状態にあり、からみ合い、凝
集等はほとんどないものである。Furthermore, since there is no entanglement in the acicular hydrated ferric oxide particles, agglomeration due to sintering during the heat treatment of the dehydration, reduction, and oxidation steps is extremely unlikely to occur, and even after forming magnetite or maghemite, the hydrated ferric oxide particles are not entangled. Same as 2-iron -
The individual particles are in a separate state, and there is almost no entanglement or aggregation.
更に前記した従来技術の如く、針状含水酸化第二鉄粒子
に対し粒子自体を破壊するような力、例えば機械粉砕等
は使用しないので、湿式反応により生成した針状含水酸
化第二鉄粒子の針状性を継承したままの目的物、即ち針
状マグネタイト粒子又は針状マグヘマイト粒子が得られ
る。Furthermore, as in the prior art described above, since force that would destroy the acicular hydrated ferric oxide particles, such as mechanical crushing, is not used, the acicular hydrated ferric oxide particles produced by a wet reaction are The target object, ie, acicular magnetite particles or acicular maghemite particles, which retains the acicular property is obtained.
また、上記針状マグネタイト粒子又は針状マグヘマイト
粒子がバラバラにほぐれた状態にあり、且つ含水酸化第
二鉄粒子の針状性を継承したものとなる効果により、該
粒子の吸油量並びに該粒子のカサ密度は大幅に改良され
、優れた粉体特性となる。In addition, due to the effect that the acicular magnetite particles or acicular maghemite particles are in a state of being loosened apart and inherit the acicularity of the hydrous ferric oxide particles, the oil absorption amount of the particles and the acicular maghemite particles are The bulk density is significantly improved, resulting in excellent powder properties.
更にこの結果から上記針状マグネタイト粒子、針状マグ
ヘマイト粒子を磁気塗料とした場合には優れた分散性を
示す磁気塗料となり、更には磁気テープ等の磁気記録材
料に使用した場合に＆転配向性、充填性に富み、電磁気
特性の極めて優れた磁気テープ等が得られる。Furthermore, these results show that when the above-mentioned acicular magnetite particles and acicular maghemite particles are used as a magnetic coating, it becomes a magnetic coating that exhibits excellent dispersibility, and furthermore, when used in magnetic recording materials such as magnetic tapes, it has excellent transorientation properties. , a magnetic tape etc. which is rich in filling properties and has extremely excellent electromagnetic properties can be obtained.
更にまた、マグネタイト又はマグヘマイトとした後で界
面活性剤により被覆した場合には、上記説明した通りの
個々の粒子ノからみ合い、凝集等がなくバラバラｆ）状
態とし、且つ針状性を継承している効果、及び吸油量、
充填率の改良等の効果に加えて界面活性効果により本来
親水性であるマグネタイト又はマグヘマイトが親油性と
なり、後に磁気塗料を製造する場合の有機溶媒等に上記
マグネタイト又はマグヘマイト粒子を練り込むに際して
も非常に都合の良い粉末となる。Furthermore, when magnetite or maghemite is formed and then coated with a surfactant, the individual particles are intertwined as explained above, and the particles are separated without agglomeration. effect and oil absorption amount,
In addition to the effects of improving the filling rate, the surfactant effect makes magnetite or maghemite, which is originally hydrophilic, lipophilic, making it extremely effective when the magnetite or maghemite particles are mixed into organic solvents used to produce magnetic paints. It becomes a convenient powder.
従って上記のようにして得た磁性酸化鉄粉末を用いると
電磁気特性の優れた磁気テープ等の磁気記録材料が極め
て得易い。Therefore, by using the magnetic iron oxide powder obtained as described above, it is extremely easy to obtain magnetic recording materials such as magnetic tapes with excellent electromagnetic properties.
尚、この時の界面活性剤による被覆効果は、針状含水酸
化第二鉄粒子の存在する反応母液中に添加する前記リン
酸塩との相乗効果が生ずる為か、通常の製造法により得
られた針状マグネタイト粒子又は針状マグヘマイト粒子
に対して施した場合に比し極めて優れた効果を発揮する
ものである。The coating effect of the surfactant at this time may be due to a synergistic effect with the phosphate added to the reaction mother liquor in which the acicular hydrated ferric oxide particles are present, but cannot be obtained by the normal manufacturing method. It exhibits an extremely superior effect compared to when applied to acicular magnetite particles or acicular maghemite particles.
尚、本発明は従来より針状マグネタイト粒子又は針状マ
グヘマイト粒子の製造に際し、各種特性の向上の為に含
有させているＳｉ、Ａｌ、Ｃｒ。In addition, in the present invention, Si, Al, and Cr have been conventionally contained in order to improve various properties when producing acicular magnetite particles or acicular maghemite particles.
Ｃｏ ｓ Ｎ １等のＦｅ以外の金属を含有している酸
化鉄粒子の場合にも本発明の効果は有効に働くものであ
る。The effects of the present invention also work effectively in the case of iron oxide particles containing metals other than Fe, such as CosN1.
次に本発明を実施例及び比較例により説明する６実施例
Ｉ
Ｆ ｅ” ０．４５ｍｏｌ ／ ｌ！の硫酸第一鉄水溶
液２１に２．２５−ＮのＮａＯＨ水溶液１１を加え、溶
液温度４０℃において空気酸化してｐＨ１３の反応母液
から針状含水酸化第二鉄粒子を生成させた。Next, the present invention will be explained with reference to Examples and Comparative Examples. 6 Examples 2.25-N NaOH aqueous solution 11 was added to ferrous sulfate aqueous solution 21 of I Fe" 0.45 mol/l!, and the solution temperature was 40°C. Acicular hydrated ferric oxide particles were produced from the reaction mother liquor at pH 13 by air oxidation.
上記反応母液から常法により水洗、１過、乾燥して得た
針状含水酸化第二鉄粒子粉末を試料Ａとする。Sample A is an acicular hydrated ferric oxide particle powder obtained from the above reaction mother liquor by washing with water, filtering once, and drying.
一方、上記ｐＨ１３の反応母液に４９％硫酸約２１０−
を徐々に加えてｐＨを３．３とした後メタリン酸ナトリ
ウム０．４（Ｈ’を含む水溶液１００１ｒ１１（含水酸
化第二鉄に対しＰＯ８として０．３９重重量化相当する
。On the other hand, about 210 - 49% sulfuric acid was added to the reaction mother liquor at pH 13.
was gradually added to adjust the pH to 3.3, and then 1001r11 of an aqueous solution containing 0.4 (H') of sodium metaphosphate (equivalent to 0.39 weight as PO8 based on hydrated ferric oxide).
）を添加し３０分間攪拌した。その後常法により水洗、
ｒ過し、１２０℃にて乾燥して得た針状含水酸化第二鉄
粒子粉末を試料Ｂとする。) was added and stirred for 30 minutes. After that, wash with water using the usual method.
Specimen B is an acicular hydrated ferric oxide particle powder obtained by filtration and drying at 120°C.
このようにして得た試料Ａ及びＢのＢＥＴ法による比表
面積は共に２８ｄ／ｆであり、電子顕微鏡観察による長
軸の平均粒子径はＡ＝（１６５μ、Ｂ＝０．５２μであ
った。The specific surface areas of Samples A and B thus obtained were both 28 d/f as determined by the BET method, and the average particle diameters of the long axes as determined by electron microscopy were A=(165μ, B=0.52μ).
また試料Ａが凝集した形跡を示すことが観察されるのに
対して試料Ｂは粒子がバラバラになっており、粒子間で
の凝集は観察されなかった。In addition, sample A was observed to show evidence of aggregation, whereas sample B had particles separated, and no aggregation between particles was observed.
この様子を第１図として電子顕微鏡写真（Ｘ１００ＯＯ
）により示す。This situation is shown in Figure 1 as an electron micrograph (X100OO
).
次いで、試料Ｂの針状含水酸化第二鉄粒子粉末を空気中
３００℃にて加熱脱水し、引きつづき水素気流中３３０
℃にて還元して針状マグネタイト粒子粉末とした後、空
気中２５０℃にて酸化することにより針状マグヘマイト
粒子粉末を得た。Next, the acicular hydrated ferric oxide particles of sample B were heated and dehydrated in air at 300°C, and then heated in a hydrogen stream for 330°C.
After reduction at 0.degree. C. to obtain acicular magnetite particles, the powder was oxidized in air at 250.degree. C. to obtain acicular maghemite particles.
得られた針状マグヘマ４ト粒子粉末は、電子顕微鏡観察
によると針状含水酸化第二鉄粒子の場合と同様にバラバ
ラの粒子から成り、粒子間の凝集は観察されなかった。When observed under an electron microscope, the obtained acicular Maghemat powder consisted of discrete particles, similar to the case of acicular hydrated ferric oxide particles, and no aggregation between the particles was observed.
この様子を第２図として電子顕微鏡写真（Ｘ１００ＯＯ
）により示す。This situation is shown in Figure 2 as an electron micrograph (X100OO
).
続いて上記針状マグヘマイト粒子粉末１５ｆにリン酸エ
ステル（東邦イヒ剛勾製ＧＡＦＡＫＲＡ−６００）０．
００７５ｒを含む水溶液１０ｍ（マグネタイトに対して
約０．０５重重量圧相当する。Subsequently, 0.00% of phosphoric acid ester (GAFAKRA-600 manufactured by Toho Ihi Koko) was added to the acicular maghemite particle powder 15f.
10 m of an aqueous solution containing 0075r (equivalent to about 0.05 gravity pressure relative to magnetite).
）を添加し、ライカイ機（石川蛛製）にて混合した後１
００℃にて乾燥した。) and mixed with a Raikai machine (manufactured by Ishikawa Hina) 1
It was dried at 00°C.
このようにして得た針状マグヘマイト粒子粉末の磁気特
性は、抗磁力Ｈｃ：３８５０ｅ、飽和磁気σｓ ： ７
３．５ ｅｍｕ／ ｔであり、粉体特性は、吸油量：２
５ｍ／！／１００ｒ、カサ密度：０．９５ｆ／−であっ
た。The magnetic properties of the acicular maghemite particles thus obtained are as follows: coercive force Hc: 3850e, saturation magnetism σs: 7
3.5 emu/t, and the powder properties are oil absorption: 2
5m/! /100r, bulk density: 0.95f/-.
更に上記針状マグヘマイト粒子粉末を用いて下記の組成
に配合し、ボールミルにより５時間分散した。Further, the above-mentioned acicular maghemite particles were blended into the following composition and dispersed in a ball mill for 5 hours.
その後塗料粘度が４００Ｑｃｐになるように調整し磁気
塗料を得た。Thereafter, the viscosity of the paint was adjusted to 400Qcp to obtain a magnetic paint.
針状マグヘマイト粒子粉末 １５Ｆ塩化ビニル酢
酸ビニニトリルゴム ５．４ｖニル共重合体樹脂
（７： ３）
トルエン
１２２メチルエチルケトン １２Ｓ
’メチルインブチルケトン １２ｒ上記磁性
塗料を３０μのポリエチレンテレフタレートのベースに
厚さ４μとなるように塗布して塗膜を形成し、６．２５
ｍａ＋幅に裁断して磁気テープを作製した。Acicular maghemite particle powder 15F vinyl chloride acetate vinyl nitrile rubber 5.4v Nyl copolymer resin (7:3) Toluene
122 methyl ethyl ketone 12S
'Methyl inbutyl ketone 12r The above magnetic paint was applied to a 30μ polyethylene terephthalate base to a thickness of 4μ to form a coating film, 6.25
A magnetic tape was produced by cutting to a width of ma+.
得られた磁気テープは、測定磁場２００００ｅにおいて
抗磁力Ｈｃ ： ３８６０ ｅ ｓ残留磁束密度Ｂ ｒ
： １３８５ ｇａｕｓｓ、角型Ｂｒ／Ｂｍ：０．９
１であった。The obtained magnetic tape has a coercive force Hc of 3860 e s in a measurement magnetic field of 20000 e, and a residual magnetic flux density B r
: 1385 gauss, square Br/Bm: 0.9
It was 1.
実施例 ２
Ｆ ｅ２＋０．５２ｍｏｌ ／ ｌの硫酸第一鉄水溶液
２１に２．０８−ＮのＮａＯＨ水溶液１１を加え、溶液
温度４５℃において空気酸化してｐＨ１２の反応母液か
ら針状含水酸化第二鉄粒子を生成させた。Example 2 2.08-N NaOH aqueous solution 11 was added to Fe2+0.52 mol/l ferrous sulfate aqueous solution 21, and air oxidized at a solution temperature of 45°C to produce acicular hydrated ferric oxide from the reaction mother liquor at pH 12. generated particles.
上記反応母液から常法により水洗、１過、乾燥して得た
針状含水酸化第二鉄粒子粉末を試料Ｃとする。Sample C is an acicular hydrated ferric oxide particle powder obtained from the above reaction mother liquor by washing with water, filtering once, and drying.
一方、上記ｐＨ１２の反応母液にメタリン酸ナトリウム
９，２５６ｒを含む水溶液１ｏｏｋ（含水酸化第二鉄に
対しＰＯ３としてｚ８重重量化相当する。On the other hand, 1 ook of an aqueous solution containing 9,256 r of sodium metaphosphate in the reaction mother liquor at pH 12 (equivalent to z8 weight as PO3 for hydrous ferric oxide).
）を添加し、３０分間攪拌した。その後、常法により水
洗、ｆ過し、１２０℃にて乾燥して得た針状含水酸化第
二鉄粒子粉末を試料りとする。) and stirred for 30 minutes. Thereafter, the acicular hydrated ferric oxide particle powder obtained by washing with water, filtering, and drying at 120° C. is used as a sample.
このようにして得た試料Ｃ及びＤのＢＥＴ法による比表
面積は共に３３Ｊ／ｆ？であり、電子顕微鏡観察による
長軸の平均粒子径はＣ＝０．５３μ、Ｄ二０．４８μで
あった。The specific surface areas of samples C and D thus obtained by the BET method are both 33 J/f? The average particle diameter along the long axis was C=0.53μ and D2 was 0.48μ, as observed by electron microscopy.
また試料Ｃが凝集した形跡を示すことが観察されるのに
対して試料りは実施例１で得た試料Ｂと同様に粒子がバ
ラバラになっており、粒子間での凝集は観察されなかっ
た。Furthermore, while sample C was observed to show evidence of aggregation, the particles in sample C were scattered, similar to sample B obtained in Example 1, and no aggregation between particles was observed. .
次いで、試料りの針状含水酸化第二鉄粒子粉末を空気中
３００℃にて加熱脱水し、引きつづき水素気流中３００
℃にて還元して針状マグネタイト粒子粉末を得た。Next, the sample acicular hydrated ferric oxide particle powder was dehydrated by heating at 300°C in air, and then heated at 300°C in a hydrogen stream.
The mixture was reduced at ℃ to obtain acicular magnetite particle powder.
得られた針状マグネタイト粒子粉末は、電子顕微鏡観察
の結果、実施例１で得た針状マグヘマイト粒子粉末と同
様にバラバラの粒子からなり、粒子間の凝集は観察され
なかった。As a result of electron microscopic observation, the obtained acicular magnetite particles were found to consist of discrete particles, similar to the acicular maghemite particles obtained in Example 1, and no aggregation between the particles was observed.
また、磁気特性、粉体特性の測定結果は表１に示す通り
であった。Further, the measurement results of magnetic properties and powder properties are as shown in Table 1.
次いで実施例１と同様にして磁性塗料並びに磁気テープ
を作成し、磁気特性を測定した結果、表１に示す通りで
あった。Next, a magnetic paint and a magnetic tape were prepared in the same manner as in Example 1, and the magnetic properties were measured, and the results are shown in Table 1.
実施例 ３
Ｆｅ” ０．４５ｍｏｌ／ ｌの硫酸第一鉄水溶液２１
に０．３６−ＮのＮａＯＨ水溶液１１を加え、溶液温度
４８℃において空気酸化してｐＨ４，０の反応母液から
針状含水酸化第二鉄粒子を生成させた。Example 3 Ferrous sulfate aqueous solution containing 0.45 mol/l of Fe” 21
A 0.36-N NaOH aqueous solution 11 was added to the solution, and air oxidation was performed at a solution temperature of 48° C. to produce acicular hydrated ferric oxide particles from the reaction mother liquor at pH 4.0.
上記反応母液から常法により水洗、１過、乾燥して得た
針状含水酸化第二鉄粒子粉末を試料Ｅとする。Sample E is an acicular hydrated ferric oxide particle powder obtained from the above reaction mother liquor by washing with water, filtering once, and drying.
一方、上記ｐ Ｈ４，０の反応母液にメタリン酸ナトリ
ウム０．１２ｆを含む水溶液ｔｏｏｙ（含水酸化第二鉄
に対しＰＯ８として０．１重量袈に相当する。On the other hand, an aqueous solution containing 0.12 f of sodium metaphosphate was added to the reaction mother liquor at pH 4.0 (corresponding to 0.1 weight of water as PO8 based on hydrated ferric oxide).
）を添加し、３０分間攪拌した。その後、常法により水
洗、濾過し、１２０°Ｃにて乾燥して得た針状含水酸化
第二鉄粒子粉末を試料Ｆとする。) and stirred for 30 minutes. Sample F is then obtained by washing with water, filtering, and drying at 120° C. in a conventional manner to obtain an acicular hydrated ferric oxide particle powder.
このようにして得た試料Ｅ及びＦのＢＥＴ法による比表
面積は共に４０ｍ’／Ｓ’であり、電子顕微鏡観察によ
る長軸の平均粒子径はＥ＝０．４０μ、Ｆ＝０．３３μ
であった。The specific surface area of Samples E and F thus obtained by the BET method are both 40 m'/S', and the average particle diameter of the long axis by electron microscopy is E = 0.40μ and F = 0.33μ.
Met.
また試料Ｅが凝集した形跡を示すことが観察されるのに
対して、試料Ｆは実施例１で得た試料Ｂと同様に粒子が
バラバラになっており、粒子間での凝集は観察されなか
った。In addition, sample E is observed to show evidence of aggregation, whereas sample F has particles that are separated, similar to sample B obtained in Example 1, and no aggregation between particles is observed. Ta.
次いで、試料Ｆの針状含水酸化第二鉄粒子粉末を空気中
３００℃にて加熱脱水し、引きつづき水素気流中３３０
℃にて還元して針状マグネタイト粒子粉末とした後、空
気中２５０℃にて酸化することにより針状マグヘマイト
粒子粉末を得た。Next, the acicular hydrated ferric oxide particles of Sample F were heated and dehydrated in air at 300°C, and then heated in a hydrogen stream for 330°C.
After reduction at 0.degree. C. to obtain acicular magnetite particles, the powder was oxidized in air at 250.degree. C. to obtain acicular maghemite particles.
得られた針状マグヘマイト粒子粉末は、電子顕微鏡観察
の結果、実施例１で得た針状マグヘマイト粒子粉末と同
様にバラバラの粒子からなり、粒子間の凝集は観察され
なかった。As a result of electron microscopic observation, the obtained acicular maghemite particles were found to consist of discrete particles, similar to the acicular maghemite particles obtained in Example 1, and no aggregation between the particles was observed.
続いて上記針状マグヘマイト粒子粉末１５Ｆにリン酸エ
ステル（東邦化学株製ＧＡＦＡＫＲＡ−６ｏｏ）ｏ、ｏ
ｌｓｙを含む水溶液１０−（マグヘマイトに対して約０
．１重量優に相当する。Subsequently, phosphoric acid ester (GAFAKRA-6oo manufactured by Toho Chemical Co., Ltd.) o, o was added to the acicular maghemite particle powder 15F.
Aqueous solution containing lsy 10-(approximately 0 for maghemite
．． Equivalent to well over 1 weight.
）を添加し、ライカイ機（石Ｊｌｌｌ１ｍ）にて混合し
た後１００℃にて乾燥した。) was added, mixed using a Raikai machine (Ishi Jlll 1m), and then dried at 100°C.
このようにして得た針状マグヘマイト粒子粉末の磁気特
性、粉体特性の測定結果は表１に示す通りであった。The results of measuring the magnetic properties and powder properties of the acicular maghemite particles thus obtained are shown in Table 1.
次いで、実施例１と同様にして磁性塗料並びに磁気テー
プを作製し、磁気特性を測定した結果、表１に示す通り
であった。Next, a magnetic paint and a magnetic tape were produced in the same manner as in Example 1, and the magnetic properties were measured, and the results are shown in Table 1.
比較例
Ｆ ｅ” ０．５２ｍｏｌ／ ｌの硫酸第一鉄水溶液２
１に２．０８−ＮのＮａＯＨ水溶液１１を加え、溶液温
度４５℃において空気酸化してｐＨ１２の反応母液から
針状含水酸化第二鉄粒子を生成させた。Comparative Example F e” 0.52 mol/l ferrous sulfate aqueous solution 2
A 2.08-N NaOH aqueous solution 11 was added to 1 and air oxidized at a solution temperature of 45° C. to produce acicular hydrated ferric oxide particles from the reaction mother liquor at pH 12.
その後、常法により水洗、濾過し、１２０℃にて乾燥し
て針状含水酸化第二鉄粒子粉末を得た。Thereafter, the mixture was washed with water, filtered, and dried at 120° C. to obtain acicular hydrated ferric oxide particles.
このようにして得た針状含水酸化第二鉄粒子粉末のＢＥ
Ｔ法による比表面積は３３＆／７であり、電子顕微鏡観
察による長軸の平均粒子径は０．５３μであった。BE of the acicular hydrated ferric oxide particle powder thus obtained
The specific surface area by the T method was 33&/7, and the average particle diameter along the long axis was 0.53 μm by electron microscopy.
また上記針状含水酸化第二鉄粒子粉末は、粒子がからみ
合っていたり、あるいは凝集した粒子群から成っている
ことが観察された。Further, it was observed that the acicular hydrated ferric oxide particles were composed of entangled particles or aggregated particle groups.
この様子を第３図として電子顕微鏡写真（Ｘ １０００
０）により示す。This situation is shown in Figure 3 as an electron micrograph (X 1000
0).
次いで、上記針状含水酸化第二鉄粒子粉末を、空気中３
００℃にて加熱脱水し、引きつづき水素気流中３３０℃
にて還元して針状マグネタイト粒子粉末とした後、空気
中２５０℃にて酸化することにより針状マグヘマイト粒
子粉末を得た。Next, the acicular hydrated ferric oxide particle powder was immersed in air for 30 minutes.
Dehydrated by heating at 00℃ and then heated to 330℃ in a hydrogen stream.
The powder was reduced to obtain acicular magnetite particles, and then oxidized in air at 250°C to obtain acicular maghemite particles.
得らし？、：針状マグヘマイト粒子粉末を試料（イ）と
スル。Is it worth it? ,: Acicular maghemite particle powder sample (A).
試料（イ）は電子顕微鏡観察の結果、粒子がからみ合っ
ていたり、あるいは凝集した粒子群から成っていること
が観察された。As a result of electron microscopy observation of sample (a), it was observed that the particles were entangled or consisted of agglomerated particle groups.
この様子を第４図として電子顕微鏡観察により示す。This situation is shown in FIG. 4 by electron microscope observation.
続いて上記針状マグヘマイト粒子粉末１５ｆにリン酸エ
ステル（東邦化学■製ＧＡＦＡＫＲＡ−６００）０．０
７５Ｆを含む水溶液１Ｏ−（マグヘマイトに対して約０
．５重量優に相当する。Subsequently, 0.0 phosphoric acid ester (GAFAKRA-600 manufactured by Toho Chemical ■) was added to the acicular maghemite particle powder 15f.
Aqueous solution containing 75F 1O- (approximately 0 for maghemite
．． Equivalent to well over 5 weight.
）をライカイ機（石川株製）にて混合した後１００℃に
て乾燥した。) were mixed using a Raikai machine (manufactured by Ishikawa Co., Ltd.) and then dried at 100°C.
得られた針状マグヘマイト粒子粉末を試料（ロ）とする
。The obtained acicular maghemite particle powder is used as a sample (b).
このようにして得た試料（イ）及び←）の針状マグヘマ
イト粒子粉末の磁気特性、粉体特性の測定結果は表１に
示す通りであった。The results of measuring the magnetic properties and powder properties of the acicular maghemite particles of samples (a) and ←) obtained in this manner are as shown in Table 1.
次いで、実施例１と同様にして磁性塗料並びに磁気テー
プを作製し、磁気特性を測定した結果、表１に示す通り
であった。Next, a magnetic paint and a magnetic tape were produced in the same manner as in Example 1, and the magnetic properties were measured, and the results are shown in Table 1.
図面はいずれも電子顕微鏡写真（Ｘ１００ＯＯ）であり
、第１図は実施例１における試料Ｂの針状含水酸化第二
鉄粒子、第２図は実施例１により得た針状マグヘマイト
粒子、第３図は比較例における針状含水酸化第二鉄粒子
、第４図は比較例により得た試料（イ）の針状マグヘマ
イト粒子を示す。The drawings are all electron micrographs (X100OO). Figure 1 shows acicular hydrated ferric oxide particles of sample B in Example 1, Figure 2 shows acicular maghemite particles obtained in Example 1, and Figure 3 shows acicular maghemite particles obtained in Example 1. The figure shows acicular hydrated ferric oxide particles in a comparative example, and FIG. 4 shows acicular maghemite particles of sample (a) obtained in the comparative example.
Claims (1)
水酸化第二鉄粒子を生成させ、該生成反応が完了してい
る反応母液中に、含水酸化第二鉄に対し０．１〜１５重
量袈のリン酸塩（ＰＯ３に換算）を添加し、攪拌した後
、針状含水酸化第二鉄粒子をＰ別、水洗、乾燥し、次い
で常法により加熱脱水、還元をして針状マグネタイト粒
子粉末とすることを特徴とする磁気記録材料用針状磁性
酸化鉄粒子粉末の製造法。 ２ 第一鉄塩溶液とアルカリとの湿式反応により針状含
水酸化第二鉄粒子を生成させ、該生成反応が完了してい
る反応母液中に、含水酸化第二鉄に対し０．１〜１５重
量優のリン酸塩（ＰＯ３に換算）を添加し、攪拌した後
、針状含水酸化第二鉄粒子をＰｙ３Ｉｌ、水洗、乾燥し
、次いで常法により加熱脱水、還元をして針状マグネタ
イト粒子とした後、該針状マグネタイト粒子を０．０１
〜２重量多の界面活性剤により被覆することを特徴とす
る磁気記録材料用針状磁性酸化鉄粒子粉末の製造法。 ３ 第一鉄塩溶液とアルカリとの湿式反応により針状含
水酸化第二鉄粒子を生成させ、該生成反応が完了してい
る反応母液中に、含水酸化第二鉄に対し０．１〜１５重
量多のリン酸塩（ＰＯ３に換算）を添加し、攪拌した後
、針状含水酸化第二鉄粒子をＰ別、水洗、乾燥し、次い
で常法により加熱脱水、還元、酸化をして針状マグヘマ
イト粒子粉末とすることを特徴とする磁気記録材料用針
状磁性酸化鉄粒子粉末の製造法。 ４ 第一鉄塩溶液とアルカリとの湿式反応により針状含
水酸化第二鉄粒子を生成させ、該生成反応が完了してい
る反応母液中に、含水酸化第二鉄に対し０．１〜１５重
量饅のリン酸塩（ＰＯ３に換算）を添加し、攪拌した後
、針状含水酸化第二鉄粒子をＦ別、水洗、乾燥し、次い
で常法により加熱脱水、還元、酸化をして針状マグヘマ
イト粒子とした後、該針状マグヘマイト粒子を０．０１
〜２重量多の界面活性剤により被覆することを特徴とす
る磁気記録材料用針状磁性酸化鉄粒子粉末の製造法。[Claims] 1. Acicular hydrated ferric oxide particles are produced by a wet reaction between a ferrous salt solution and an alkali, and the hydrated ferric oxide particles are added to the reaction mother liquor in which the production reaction has been completed. After adding 0.1 to 15 weight of phosphate (in terms of PO3) and stirring, the acicular hydrated ferric oxide particles are separated from P, washed with water, dried, and then heated and dehydrated and reduced by a conventional method. A method for producing acicular magnetic iron oxide particles for magnetic recording materials, the method comprising: producing acicular magnetic iron oxide particles for magnetic recording materials. 2. Acicular hydrated ferric oxide particles are produced by a wet reaction between a ferrous salt solution and an alkali, and 0.1 to 15 After adding a large amount of phosphate (in terms of PO3) and stirring, the acicular hydrated ferric oxide particles are washed with Py3Il, water, dried, and then heated and dehydrated and reduced by a conventional method to obtain acicular magnetite particles. After that, the acicular magnetite particles were reduced to 0.01
1. A method for producing acicular magnetic iron oxide particles for magnetic recording materials, the method comprising coating with a surfactant in an amount of ~2% by weight. 3. Acicular hydrated ferric oxide particles are produced by a wet reaction between a ferrous salt solution and an alkali, and 0.1 to 15 After adding a large amount of phosphate (in terms of PO3) and stirring, the needle-shaped hydrated ferric oxide particles are separated from P, washed with water, dried, and then heated, dehydrated, reduced, and oxidized by conventional methods to form needles. 1. A method for producing acicular magnetic iron oxide particles for magnetic recording materials, the method comprising forming acicular magnetic iron oxide particles into powdered maghemite particles. 4. Acicular hydrated ferric oxide particles are produced by a wet reaction between a ferrous salt solution and an alkali, and 0.1 to 15 After adding a heavy weight of phosphate (converted to PO3) and stirring, the needle-shaped hydrated ferric oxide particles are separated by F, washed with water, dried, and then heated, dehydrated, reduced, and oxidized by a conventional method to form needles. After forming acicular maghemite particles, the acicular maghemite particles are
1. A method for producing acicular magnetic iron oxide particles for magnetic recording materials, the method comprising coating with a surfactant in an amount of ~2% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP52104095A JPS5854487B2 (en) | 1977-08-29 | 1977-08-29 | Method for producing acicular magnetic iron oxide particle powder for magnetic recording materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP52104095A JPS5854487B2 (en) | 1977-08-29 | 1977-08-29 | Method for producing acicular magnetic iron oxide particle powder for magnetic recording materials |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5437297A JPS5437297A (en) | 1979-03-19 |
| JPS5854487B2 true JPS5854487B2 (en) | 1983-12-05 |
Family
ID=14371549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP52104095A Expired JPS5854487B2 (en) | 1977-08-29 | 1977-08-29 | Method for producing acicular magnetic iron oxide particle powder for magnetic recording materials |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5854487B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6018182U (en) * | 1983-07-11 | 1985-02-07 | 住建コンクリ−ト工業株式会社 | Two-piece box culvert |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5891039A (en) * | 1981-11-27 | 1983-05-30 | Ishihara Sangyo Kaisha Ltd | Manufacture of needlelike alpha-feooh for magnetic recording material |
| AU558199B2 (en) * | 1982-09-16 | 1987-01-22 | Ishihara Sangyo Kaisha Ltd. | Production of magnetic powder |
| JPS6069822A (en) * | 1983-08-19 | 1985-04-20 | Toshiba Corp | Magnetic recording medium |
| US4774012A (en) * | 1986-01-30 | 1988-09-27 | Ishihara Sangyo Kaisha, Ltd. | Cobalt-containing ferromagnetic iron oxide powder and process for producing the same |
| JPH0568446U (en) * | 1992-02-26 | 1993-09-17 | ショウ ニォウ チィ | Rice scoop for resin processing pot |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5057996A (en) * | 1973-09-21 | 1975-05-20 |
-
1977
- 1977-08-29 JP JP52104095A patent/JPS5854487B2/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5057996A (en) * | 1973-09-21 | 1975-05-20 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6018182U (en) * | 1983-07-11 | 1985-02-07 | 住建コンクリ−ト工業株式会社 | Two-piece box culvert |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5437297A (en) | 1979-03-19 |
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