JPS6251208B2 - - Google Patents
Info
- Publication number
- JPS6251208B2 JPS6251208B2 JP58181290A JP18129083A JPS6251208B2 JP S6251208 B2 JPS6251208 B2 JP S6251208B2 JP 58181290 A JP58181290 A JP 58181290A JP 18129083 A JP18129083 A JP 18129083A JP S6251208 B2 JPS6251208 B2 JP S6251208B2
- Authority
- JP
- Japan
- Prior art keywords
- aqueous solution
- particles
- magnetite
- ferrous salt
- ferrous
- 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.)
- Expired
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- 239000002245 particle Substances 0.000 claims description 75
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims description 56
- 239000007864 aqueous solution Substances 0.000 claims description 43
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 35
- 238000006243 chemical reaction Methods 0.000 claims description 28
- 239000000843 powder Substances 0.000 claims description 19
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 229910001854 alkali hydroxide Inorganic materials 0.000 claims description 11
- 239000000084 colloidal system Substances 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 7
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 claims description 7
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 claims description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 5
- 230000001747 exhibiting effect Effects 0.000 claims description 5
- 239000007789 gas Substances 0.000 claims description 5
- 239000001301 oxygen Substances 0.000 claims description 5
- 229910052760 oxygen Inorganic materials 0.000 claims description 5
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 238000007039 two-step reaction Methods 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 41
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 18
- 238000004040 coloring Methods 0.000 description 13
- 239000003973 paint Substances 0.000 description 10
- 239000000049 pigment Substances 0.000 description 9
- 238000010521 absorption reaction Methods 0.000 description 6
- 239000003513 alkali Substances 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 230000005291 magnetic effect Effects 0.000 description 6
- 239000003921 oil Substances 0.000 description 6
- 238000000635 electron micrograph Methods 0.000 description 5
- 239000012266 salt solution Substances 0.000 description 5
- 239000011790 ferrous sulphate Substances 0.000 description 4
- 235000003891 ferrous sulphate Nutrition 0.000 description 4
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 230000035699 permeability Effects 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000012798 spherical particle Substances 0.000 description 3
- 239000003981 vehicle Substances 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 238000004438 BET method Methods 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000004359 castor oil Substances 0.000 description 1
- 235000019438 castor oil Nutrition 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- ZEMPKEQAKRGZGQ-XOQCFJPHSA-N glycerol triricinoleate Natural products CCCCCC[C@@H](O)CC=CCCCCCCCC(=O)OC[C@@H](COC(=O)CCCCCCCC=CC[C@@H](O)CCCCCC)OC(=O)CCCCCCCC=CC[C@H](O)CCCCCC ZEMPKEQAKRGZGQ-XOQCFJPHSA-N 0.000 description 1
- 229910052598 goethite Inorganic materials 0.000 description 1
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 235000010215 titanium dioxide Nutrition 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Description
【発明の詳細な説明】
本発明は、第一鉄塩水溶液を用いて球型を呈し
たマグネタイト粒子粉末の製造法に関するもので
あり、詳しくは、第一鉄塩水溶液中に未反応の
Fe2+を残すことなくFe2+の全量から粒度が均斉
で優れた分散性と高い着色力を有し、且つ、過
性、粉砕容易性等の生産性に優れた球型を呈した
マグネタイト粒子粉末を得ることを目的とする。
その主な用途は、塗料用黒色顔料粉末、静電複
写用の磁気トナー用材料粉末である。
マグネタイト粒子は、黒色顔料として広く一般
に使用されており、省エネルギー時代における作
業能率の向上並びに塗膜物性の改良という観点か
ら、塗料の製造に際して、マグネタイト粒子粉末
のビヒクル中への分散性の改良が、益々、要望さ
れている。
塗料の製造に際して、顔料粉末のビヒクル中へ
の分散性が良好であるか否かは、塗料の製造工程
における作業能率を左右するとともに、塗膜の諸
物性を決定する極めて重要な因子となる。
このことは、例えば、色材協会誌49巻第１号
（1976年）の第８頁の次のような記載からも明ら
かである。
「………塗膜の具備すべき諸特性は一口にいつ
て、同一顔料であれば塗膜中における顔料の分散
性により、その大部分が決定されるといつても過
言ではないように思われる。塗膜中の顔料の分散
性が良好であれば、色調は鮮明となり、着色力、
いんぺい力等顔料本来の基本的性質も向上するこ
とは理論の教えるところである。また塗膜の光
沢、鮮映性、機械的性質、塗膜の耐透気性などが
良好となり、これは塗膜の耐久性を向上させる結
果となる。このように塗膜中の顔料の分散性は塗
膜の諸物性を決定するきわめて大事な要因である
ことが理解できる。」
一方、近年における静電複写機の普及はめざま
しく、それに伴い、現像剤である磁気トナーの研
究開発がさかんであり、その特性向上が要求され
ている。
例えば、特開昭54−122129号公報に次のように
記載されている。
「………磁気トナーはトナー結着剤中に磁性微
粒子が相当量混入されるが、磁性微粒子は一般に
トナー結着樹脂中への分散性が悪く、製造上バラ
ツキのない均一なトナーを得ることが困難であ
り、更に、絶縁性トナーではトナーの電気抵抗の
低下の原因ともなる。」更に、特公昭53−21656号
公報には「………酸化鉄を現像剤粒子全体に均一
に分布させることにより静電潜像の顕像化に必要
な適度な帯磁性を得」ることが可能であると記載
されている。
従来、第一鉄塩水溶液とアルカリとを反応させ
て得られた水酸化第一鉄を含む反応水溶液に酸素
含有ガスを通気することによりマグネタイト粒子
粉末を製造するにあたり、上記反応水溶液のPHに
より生成マグネタイト粒子の形状が種々異なるこ
とが知られている。
即ち、この事実は、粉体粉末冶金協会昭和46年
度秋季大会講演概要集第112頁第14〜19行の「硫
酸第一鉄水溶液（139ｇ／0.7）に空気を吹き込
み、撹拌しながら水酸化ナトリウム水溶液（40〜
44ｇ／0.3）を加え、50℃に昇温して５時間保
つて微粒子を得た。粒子の外形を変えるためPHを
変化させた。PHは水酸化ナトリウムの量をコント
ロールし、酸性側（NaOH40〜41ｇ／0.3）で
凝六面体粒子を、アルカリ性側（43ｇ以上／0.3
）で八面体粒子を、中性附近（NaOH42ｇ／
0.3）では多面体化した球状に近い粒子を得
た。」なる記載及び特公昭44−668号公報特許請求
の範囲の「………Fe（OH）2コロイドを含むPH10
以上の水溶液を45℃以上70℃以下の温度に保持
し、撹拌により液中に存在する沈澱粒子が充分に
運動している状態で酸化反応を行うことにより、
………粒状または立方状（六面体）を呈した……
…黒色強磁性粒子（マグネタイト粒子）より成る
沈澱を製造………」なる記載から明らかである。
本発明者は、マグネタイト粒子の形状に着目
し、優れた分散性と高い着色力を有するマグネタ
イト粒子を得ようとすれば、カサ密度が大きく、
吸油量の低い球型を呈した粒子であることが必要
であると考え、球型を呈したマグネタイト粒子を
得ることが必要であると考えた。
上述した通り、球型を呈したマグネタイト粒子
は、中性附近の水溶液中で生成されることが知ら
れているが、この場合には、第一鉄塩水溶液中の
Fe2+の全量をマグネタイト粒子に変換すること
は困難で未反応のFe2+が残存する為、収率が低
く、その上未反応のFe2+は排水公害の原因とな
るのでその対策が必要であつた。
第一鉄塩水溶液中のFe2+の全量からマグネタ
イト粒子を生成し収率を高めようとすれば、第一
鉄塩水溶液と該第一鉄塩水溶液に対し１当量以上
のアルカリとを反応させる必要があり、この場合
にはPH11程度以上のアルカリ反応水溶液となり、
生成マグネタイト粒子は六面体又は八面体粒子と
なる為かさ密度が小さく吸油量が高くなり、分散
性及び着色力が悪いものであつた。
本発明者は、上述したところに鑑み、第一鉄塩
水溶液中に未反応のFe2+を残すことなくFe2+の
全量から粒度が均斉で優れた分散性と高い着色力
を有し、且つ、優れた生産性を有するマグネタイ
ト粒子を得るべく、種々検討を重ねた結果、本発
明に到達したのである。
即ち、本発明は、第一鉄塩水溶液と該第一鉄塩
水溶液中のFe2+に対し0.80〜0.99当量の水酸化ア
ルカリとを反応させて得られた水酸化第一鉄コロ
イドを含む第一鉄塩水溶液に、70℃〜100℃の温
度範囲で加熱しながら酸素含有ガスを通気するこ
とにより、上記水酸化第一鉄コロイドから球型を
呈したマグネタイト粒子を生成させる第一段と、
該第一段反応終了後残存Fe2+に対し1.00当量以上
の水酸化アルカリを添加し第一段反応と同条件下
で加熱酸化する第二段との二段階反応から成るこ
とを特徴とする球型を呈したマグネタイト粒子粉
末の製造法である。
本発明の構成、効果を説明すれば以下の通りで
ある。
先ず、本発明者は、顔料として優れた分散性と
高い着色力を有するマグネタイト粒子を得る為に
は、球型を呈したマグネタイト粒子を得ることが
肝要であり、その為には中性附近における反応で
あることが必要であることを知つた。
次に、本発明者は、第一鉄塩水溶液中に未反応
のFe2+を残すことなく原料第一鉄塩水溶液中の
Fe2+の全量からマグネタイトを生成することに
より収率を高め、しかも、優れた生産性を得るた
めには、アルカリ性側における反応であることが
必要であることを知つた。
そこで、本発明者は、原料第一鉄塩水溶液から
あらかじめ、Fe2+の一部をアルカリの添加によ
り沈澱し、次いで加熱酸化してマグネタイトとす
る第一段と、該第一段反応終了後未反応のFe2+
に対して1.00当量以上のアルカリを添加して沈澱
し、次いで加熱酸化する第二段の二段階から成る
反応をすれば、第一鉄塩水溶液中に未反応の
Fe2+を残すことなく原料第一鉄塩水溶液中の
Fe2+の全量から粒度が均斉で優れた分散性と高
い着色力を有し、且つ、優れた生産性を有する球
型を呈したマグネタイト粒子が得られると考え、
第一段反応におけるFe2+の沈澱量、該Fe2+の沈
澱量と未反応のFe2+量との関係、アルカリの種
類、反応温度及び生成物マグネタイト粒子の形状
について種々検討を行なつた。
そして、第一鉄塩水溶液と該第一鉄塩水溶液中
のFe2+に対し0.80〜0.99当量の水酸化アルカリを
反応させて得られた水酸化第一鉄コロイドを含む
第一鉄塩反応水溶液に、70℃〜100℃の温度範囲
で加熱しながら酸素含有ガスを通気することによ
り、上記水酸化第一鉄コロイドから球型を呈した
マグネタイト粒子を生成させる第一段と、該第一
段反応終了後残存Fe2+に対し1.00当量以上の水酸
化アルカリを添加し第一段反応と同条件下で加熱
酸化する第二段との二段階から成る反応をした場
合には、第二段反応では第一段反応で生成した球
型を呈したマグネタイト粒子表面にマグネタイト
がエピタキシヤル成長し、六面体または八面体を
呈したマグネタイト粒子を生成しないので球型を
呈した粒度分布が均斉で、優れた分散性と高い着
色力を有し、且つ、過性、粉砕容易性等の生産
性に優れた球型を呈したマグネタイト粒子粉末を
得ることができるという知見を得た。
次に、本発明方法実施にあたつての諸条件につ
いて述べる。
本発明において使用される第一鉄塩水溶液とし
ては、硫酸第一鉄水溶液、塩化第一鉄水溶液等が
ある。
本発明において使用される水酸化アルカリとし
ては、水酸化ナトリウム、水酸化カリウム等アル
カリ金属の水酸化物、水酸化マグネシウム、水酸
化カルシウム等のアルカリ土類金属の水酸化物で
ある。
本発明の第一段反応において使用する水酸化ア
ルカリの量は、第一鉄塩水溶液中のFe2+に対し
0.80〜0.99当量である。
0.80当量以下又は0.99当量以上である場合に
は、球型を呈したマグネタイト粒子を生成するこ
とが困難である。
本発明の第一段反応における反応温度は70℃〜
100℃である。
70℃以下である場合には、針状晶ゲータイト粒
子が混在し、100℃以上でも球型を呈したマグネ
タイト粒子は生成するが工業的ではない。
酸化手段は酸素含有ガス（例えば空気）を液中
に通気することにより行なう。
本件発明の第二段反応において使用する水酸化
アルカリの量は、第一段反応における残存Fe2+
に対して1.00当量以上である。
1.00当量以下ではFe2+が全量沈澱しない。1.00
当量以上の工業性を肝案した量が好ましい量であ
る。
本発明における第二段反応の反応温度は第一段
反応と同一でよい。また、酸化手段も同一でよ
い。
以上の通りの構成の本発明は、次の通りの効果
を奏するものである。
即ち、本発明によれば、第一鉄塩水溶液中に未
反応のFe2+を残すことなくFe2+の全量から粒度
が均斉で、優れた分散性と高い着色力を有し、且
つ、過性、粉砕容易性等の生産性に優れた球型
を呈したマグネタイト粒子粉末を得ることができ
る。塗料の製造に際して、上記球型を呈したマグ
ネタイト粒子粉末を用いた場合には、ビヒクル中
への分散が良好であるので、光沢、鮮明性、耐久
性の塗膜特性の改良が可能となり、又、作業能率
も向上する。
また、磁気トナーの製造に際して、上記球型を
呈したマグネタイト粒子粉末を用いた場合には、
樹脂への分散性が良好であるので、適当な帯磁性
を有し、画像濃度の優れた画質を得ることができ
る。
次に、実施例並びに比較例により本発明を説明
する。
尚、以下の実施例並びに比較例における平均粒
子径はBET法により、吸油量及びカサ密度はJIS
K5101に記載の方法により測定し、着色力は測色
用試料片を東京電色製測色色差計（TC−5D）を
用いて測色して得られたＬ値（明度）で示した。
Ｌ値が低い程、着色力が優れたものであり、分散
性が良好であることを示す。測色用試験片は、マ
グネタイト粒子粉末0.5ｇ及びチタン白1.5ｇとヒ
マシ油1.5c.c.をフーバー式マーラーで練つてペー
スト状とし、このペーストにクリヤラツカー4.5
ｇを加え混練し塗料化して、ミラコート紙上に
6milのアプリケータを用いて塗布することによつ
て得た。
実施例 １
Fe2+1.5mol／を含む硫酸第一鉄水溶液20
を、あらかじめ、反応器中に準備された2.64−Ｎ
のNaOH水溶液20に加え（Fe2+に対し0.88当量
に該当する。）、PH6.9、温度90℃においてFe
（OH）2を含む第一鉄塩水溶液の生成を行つた。
上記Fe（OH）2を含む第一鉄塩水溶液に温度90
℃において毎分100の空気を240分間通気してマ
グネタイト粒子を含む第一鉄塩水溶液を生成し
た。
次いで、上記マグネタイト粒子を含む第一鉄塩
水溶液に3.78−ＮのNaOH水溶液２を加え
（Fe2+に対し1.05当量に該当する。）、PH11.8、温
度90℃において毎分20の空気を60分間通気して
マグネタイト粒子を生成した。
生成粒子は、常法により、水洗、別、乾燥、
粉砕した。
得られたマグネタイト粒子粉末は、図１に示す
電子顕微鏡写真（×20000）から明らかな通り、
球型を呈した粒子であり、且つ、粒度が均斉なも
のであつた。
また、この球状マグネタイト粒子粉末は、平均
粒子径が0.18μｍで、Ｌ値35.8、吸油量19ml／
100ｇ及びカサ密度0.54ｇ／c.c.であり、生産性の
極めて良好なものであつた。
実施例 ２〜８
第一鉄塩水溶液の種類、水酸化アルカリの種
類、濃度、第一段における使用量及び反応温度を
種々変化させた以外は実施例１と同様にしてマグ
ネタイト粒子粉末を得た。
この時の主要製造条件及び生成マグネタイト粒
子粉末の諸特性を表１に示す。
実施例２〜８で得られたマグネタイト粒子粉末
は、電子顕微鏡観察の結果、いずれも球型を呈し
た粒子であり、且つ、粒度が均斉なものであつ
た。
実施例４で得られたマグネタイト粒子粉末の電
子顕微鏡写真（×20000）を図２に示す。
比較例 １
Fe2+1.5mol／を含む硫酸第一鉄水溶液20
を、あらかじめ、反応器中に準備された3.45−Ｎ
のNaOH水溶液20に加え（Fe2+に対し1.15当量
に該当する。）、PH12.8、温度90℃においてFe
（OH）2を含む水溶液の生成を行つた。
上記Fe（OH）2を含む水溶液に温度90℃におい
て毎分100の空気を220分間通気してマグネタイ
ト粒子粉末を生成した。
得られたマグネタイト粒子粉末は、図３に示す
電子顕微鏡写真（×20000）から明らかな通り、
六面体を呈した粒子であつた。
また、この六面体を呈したマグネタイト粒子粉
末は平均粒子径が0.17μｍで、Ｌ値40.1、吸油量
29ml／100ｇ及びカサ密度0.25ｇ／c.c.であつた。
比較例 ２
Fe2+1.5mol／を含む硫酸第一鉄水溶液20
を、あらかじめ、反応器中に準備された1.92−Ｎ
のNaOH水溶液20に加え（Fe2+に対し0.64当量
に該当する。）、PH4.8、温度90℃においてFe
（OH）2を含む第一鉄塩水溶液の生成を行つた。
上記Fe（OH）2を含む第一鉄塩水溶液に温度90
℃において毎分100の空気を190分間通気してマ
グネタイト粒子粉末を生成した。
得られたマグネタイト粒子粉末は、図４に示す
電子顕微鏡写真（×20000）から明らかな通り、
不定形粒子であつた。
また、この不定形のマグネタイト粒子粉末は平
均粒子径が0.19μｍで、Ｌ値39.0、吸油量27ml／
100ｇ及びカサ密度0.34ｇ／c.c.であつた。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing spherical magnetite particles using an aqueous ferrous salt solution.
Magnetite that has a uniform particle size based on the total amount of Fe 2+ without leaving Fe 2+ , has excellent dispersibility and high coloring power, and has a spherical shape with excellent productivity such as hyperability and ease of crushing. The aim is to obtain a particulate powder. Its main uses are black pigment powder for paints and material powder for magnetic toners for electrostatic copying. Magnetite particles are widely used as black pigments, and from the viewpoint of improving work efficiency and improving the physical properties of paint films in the energy-saving era, improving the dispersibility of magnetite particles in a vehicle is important when manufacturing paints. It is increasingly requested. In the production of paints, whether or not the dispersibility of the pigment powder in the vehicle is good is an extremely important factor that not only affects the efficiency of the paint manufacturing process but also determines the various physical properties of the paint film. This is clear, for example, from the following statement on page 8 of the Coloring Materials Association Journal, Vol. 49, No. 1 (1976). ``...I think it is no exaggeration to say that most of the characteristics that a paint film should have are determined by the dispersibility of the pigment in the paint film if the pigments are the same. If the dispersibility of the pigment in the coating film is good, the color tone will be clear, and the coloring strength and
Theory teaches that the fundamental properties of pigments, such as their strength, can also be improved. Furthermore, the gloss, sharpness, mechanical properties, and air permeability of the coating film are improved, which results in improved durability of the coating film. It can thus be understood that the dispersibility of pigments in a coating film is an extremely important factor in determining the various physical properties of the coating film. On the other hand, the spread of electrostatic copying machines has been remarkable in recent years, and as a result, research and development of magnetic toner, which is a developer, has been active, and improvements in its properties are required. For example, JP-A-54-122129 describes the following. "...Magnetic toner has a considerable amount of magnetic fine particles mixed in the toner binder, but magnetic fine particles generally have poor dispersibility in the toner binder resin, so it is difficult to obtain a uniform toner with no manufacturing variations. Further, in the case of insulating toner, it may cause a decrease in the electrical resistance of the toner.'' Furthermore, Japanese Patent Publication No. 53-21656 states, ``... it is difficult to uniformly distribute iron oxide throughout the developer particles. It is stated that by doing so, it is possible to obtain an appropriate level of magnetization necessary for visualizing an electrostatic latent image. Conventionally, when manufacturing magnetite particle powder by aerating oxygen-containing gas into a reaction aqueous solution containing ferrous hydroxide obtained by reacting a ferrous salt aqueous solution with an alkali, the PH of the reaction aqueous solution was used to produce magnetite particle powder. It is known that magnetite particles have various shapes. In other words, this fact is based on the Powder Metallurgy Association 1971 Autumn Conference Abstracts, page 112, lines 14 to 19: Aqueous solution (40~
44g/0.3) was added, the temperature was raised to 50°C, and the temperature was maintained for 5 hours to obtain fine particles. The pH was changed to change the external shape of the particles. The PH controls the amount of sodium hydroxide, and the acidic side (NaOH40~41g/0.3) allows for condensed hexahedral particles, while the alkaline side (more than 43g/0.3)
) to the octahedral particles near neutrality (NaOH42g/
0.3), polyhedral, nearly spherical particles were obtained. ” and the claims of Japanese Patent Publication No. 44-668 “…PH10 containing Fe(OH) 2 colloid”
By maintaining the above aqueous solution at a temperature of 45°C or higher and 70°C or lower, and carrying out the oxidation reaction while the precipitated particles present in the liquid are sufficiently moved by stirring,
…It was granular or cubic (hexahedral)…
This is clear from the description "...manufacturing a precipitate consisting of black ferromagnetic particles (magnetite particles)...". The present inventor focused on the shape of magnetite particles, and in order to obtain magnetite particles with excellent dispersibility and high coloring power, the bulk density is large,
It was thought that it was necessary to have particles exhibiting a spherical shape with low oil absorption, and it was thought that it was necessary to obtain magnetite particles exhibiting a spherical shape. As mentioned above, it is known that magnetite particles exhibiting a spherical shape are produced in an aqueous solution near neutrality, but in this case, magnetite particles in a ferrous salt aqueous solution are
It is difficult to convert the entire amount of Fe 2+ into magnetite particles, and unreacted Fe 2+ remains, resulting in a low yield. Furthermore, unreacted Fe 2+ causes wastewater pollution, so there are no countermeasures to deal with it. It was necessary. In order to generate magnetite particles from the total amount of Fe 2+ in a ferrous salt aqueous solution and increase the yield, it is necessary to react the ferrous salt aqueous solution with an alkali equivalent of 1 equivalent or more to the ferrous salt aqueous solution. In this case, it becomes an alkaline reaction aqueous solution with a pH of about 11 or higher,
Since the produced magnetite particles were hexahedral or octahedral particles, their bulk density was low, their oil absorption was high, and their dispersibility and coloring power were poor. In view of the foregoing, the present inventor has created a ferrous salt aqueous solution that does not leave unreacted Fe 2+ and has uniform particle size from the total amount of Fe 2+ , excellent dispersibility, and high coloring power. In order to obtain magnetite particles with excellent productivity, the present invention was achieved as a result of various studies. That is, the present invention provides a ferrous hydroxide colloid obtained by reacting an aqueous ferrous salt solution with an alkali hydroxide in an amount of 0.80 to 0.99 equivalent to Fe 2+ in the aqueous ferrous salt solution. A first step of generating spherical magnetite particles from the ferrous hydroxide colloid by passing an oxygen-containing gas through the ferrous salt aqueous solution while heating it in a temperature range of 70°C to 100°C;
After completion of the first stage reaction, 1.00 equivalents or more of alkali hydroxide is added to the remaining Fe 2+ and the second stage is heated and oxidized under the same conditions as the first stage reaction. This is a method for producing spherical magnetite particles. The structure and effects of the present invention will be explained as follows. First of all, the present inventor believes that in order to obtain magnetite particles having excellent dispersibility and high coloring power as a pigment, it is important to obtain magnetite particles exhibiting a spherical shape. I learned that it needs to be a reaction. Next, the inventors of the present invention discovered that the raw material ferrous salt aqueous solution was free from unreacted Fe 2+ without leaving any unreacted Fe 2+ in the ferrous salt aqueous solution.
We learned that in order to increase the yield and obtain excellent productivity by producing magnetite from the entire amount of Fe 2+ , it is necessary to conduct the reaction on the alkaline side. Therefore, the present inventor developed a first stage in which a part of Fe 2+ is precipitated from the raw material ferrous salt aqueous solution by adding an alkali, and then heated and oxidized to form magnetite, and a first stage in which a part of Fe 2+ is precipitated from the raw material ferrous salt aqueous solution by adding an alkali, and the unreacted Fe 2+ is precipitated after the first stage reaction is completed. Fe2 +
If the reaction consists of two steps: adding 1.00 equivalents or more of alkali to precipitate it, and then heating and oxidizing it, the unreacted
in raw ferrous salt aqueous solution without leaving any Fe 2+
We believe that spherical magnetite particles with uniform particle size, excellent dispersibility, high coloring power, and excellent productivity can be obtained from the total amount of Fe 2+ .
Various studies were conducted on the amount of precipitated Fe 2+ in the first stage reaction, the relationship between the amount of precipitated Fe 2+ and the amount of unreacted Fe 2+ , the type of alkali, the reaction temperature, and the shape of the product magnetite particles. Ta. and a ferrous salt reaction aqueous solution containing a ferrous hydroxide colloid obtained by reacting the ferrous salt aqueous solution with an alkali hydroxide in an amount of 0.80 to 0.99 equivalent to Fe 2+ in the ferrous salt aqueous solution. a first step of generating spherical magnetite particles from the ferrous hydroxide colloid by aerating oxygen-containing gas while heating in a temperature range of 70°C to 100°C; and completion of the first step reaction. In the case of a two-stage reaction consisting of the first stage reaction in which 1.00 equivalents or more of alkali hydroxide is added to the residual Fe 2+ and the second stage of heating and oxidation under the same conditions, the second stage reaction Magnetite grows epitaxially on the surface of the spherical magnetite particles produced in the first stage reaction, and does not produce hexahedral or octahedral magnetite particles, resulting in uniform spherical particle size distribution and excellent dispersion. The present inventors have found that it is possible to obtain magnetite particles having a spherical shape, which has high coloring strength, and has excellent productivity such as permeability and ease of crushing. Next, various conditions for carrying out the method of the present invention will be described. Examples of the ferrous salt aqueous solution used in the present invention include a ferrous sulfate aqueous solution and a ferrous chloride aqueous solution. The alkali hydroxide used in the present invention includes alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide. The amount of alkali hydroxide used in the first stage reaction of the present invention is based on Fe 2+ in the ferrous salt aqueous solution.
It is 0.80-0.99 equivalent. When the amount is less than 0.80 equivalent or more than 0.99 equivalent, it is difficult to produce spherical magnetite particles. The reaction temperature in the first stage reaction of the present invention is 70℃ ~
It is 100℃. When the temperature is below 70°C, acicular goethite particles are mixed, and even above 100°C, spherical magnetite particles are produced, but this is not suitable for industrial use. The oxidation means is carried out by passing an oxygen-containing gas (for example, air) into the liquid. The amount of alkali hydroxide used in the second stage reaction of the present invention is determined by the amount of alkali hydroxide used in the second stage reaction of the present invention .
1.00 equivalent or more. If the amount is less than 1.00 equivalent, all Fe 2+ will not precipitate. 1.00
A preferable amount is an equivalent amount or more, taking into consideration industrial efficiency. The reaction temperature of the second stage reaction in the present invention may be the same as that of the first stage reaction. Further, the oxidation means may be the same. The present invention configured as described above has the following effects. That is, according to the present invention, the particle size is uniform from the total amount of Fe 2+ without leaving unreacted Fe 2+ in the ferrous salt aqueous solution, and it has excellent dispersibility and high coloring power, and It is possible to obtain magnetite particles having a spherical shape with excellent productivity such as permeability and ease of crushing. When the above-mentioned spherical magnetite particle powder is used in the production of paint, it is well dispersed in the vehicle, making it possible to improve coating film properties such as gloss, clarity, and durability. , work efficiency is also improved. Furthermore, when the above-mentioned spherical magnetite particles are used in the production of magnetic toner,
Since it has good dispersibility in resin, it has appropriate magnetism and can provide image quality with excellent image density. Next, the present invention will be explained with reference to Examples and Comparative Examples. In addition, the average particle diameter in the following examples and comparative examples is determined by the BET method, and the oil absorption amount and bulk density are determined by the JIS
The coloring power was measured by the method described in K5101, and the coloring power was expressed as the L value (lightness) obtained by measuring the color of a sample piece using a colorimeter (TC-5D) manufactured by Tokyo Denshoku.
The lower the L value, the better the coloring power and the better the dispersibility. The test piece for color measurement was made by kneading 0.5 g of magnetite particle powder, 1.5 g of titanium white, and 1.5 cc of castor oil into a paste using a Hoover type muller.
Add g and knead to make a paint and apply it on Miracoat paper.
It was obtained by application using a 6 mil applicator. Example 1 Ferrous sulfate aqueous solution containing 1.5 mol/Fe 2+ 20
2.64-N prepared in advance in the reactor
In addition to NaOH aqueous solution 20 (corresponds to 0.88 equivalent to Fe 2+ ), Fe
An aqueous ferrous salt solution containing (OH) 2 was produced. The above ferrous salt aqueous solution containing Fe(OH) 2 was heated to a temperature of 90°C.
A ferrous salt aqueous solution containing magnetite particles was produced by blowing air at 100 °C/min for 240 minutes. Next, 3.78-N NaOH aqueous solution 2 was added to the ferrous salt aqueous solution containing the magnetite particles (corresponding to 1.05 equivalent to Fe 2+ ), and 20 air per minute was added at a pH of 11.8 and a temperature of 90°C. Aeration was performed for 60 minutes to generate magnetite particles. The generated particles are washed with water, separated, dried, and
Shattered. As is clear from the electron micrograph (×20000) shown in Figure 1, the obtained magnetite particle powder has the following properties:
The particles had a spherical shape and were uniform in particle size. In addition, this spherical magnetite particle powder has an average particle diameter of 0.18 μm, an L value of 35.8, and an oil absorption amount of 19 ml/
The product had a bulk density of 100 g and a bulk density of 0.54 g/cc, indicating extremely good productivity. Examples 2 to 8 Magnetite particle powder was obtained in the same manner as in Example 1, except that the type of ferrous salt aqueous solution, the type and concentration of alkali hydroxide, the amount used in the first stage, and the reaction temperature were varied. . Table 1 shows the main manufacturing conditions and various properties of the produced magnetite particles. As a result of electron microscopy, the magnetite particles obtained in Examples 2 to 8 were all spherical particles with uniform particle size. An electron micrograph (×20,000) of the magnetite particles obtained in Example 4 is shown in FIG. Comparative example 1 Ferrous sulfate aqueous solution containing 1.5 mol/Fe 2+ 20
3.45-N prepared in advance in the reactor
In addition to NaOH aqueous solution 20 (corresponds to 1.15 equivalents to Fe 2+ ), Fe
An aqueous solution containing (OH) 2 was produced. Magnetite particle powder was produced by blowing 100 air per minute into the aqueous solution containing Fe(OH) 2 at a temperature of 90° C. for 220 minutes. As is clear from the electron micrograph (×20000) shown in Figure 3, the obtained magnetite particle powder has the following properties:
The particles were hexahedral. In addition, this hexahedral magnetite particle powder has an average particle diameter of 0.17 μm, an L value of 40.1, and an oil absorption amount.
The bulk density was 29 ml/100 g and 0.25 g/cc. Comparative Example 2 Ferrous sulfate aqueous solution containing 1.5 mol/Fe 2+ 20
1.92-N prepared in advance in the reactor
In addition to NaOH aqueous solution 20 (corresponds to 0.64 equivalent to Fe 2+ ), Fe
An aqueous ferrous salt solution containing (OH) 2 was produced. The above ferrous salt aqueous solution containing Fe(OH) 2 was heated to a temperature of 90°C.
Magnetite particle powder was produced by bubbling air at 100 °C per minute for 190 minutes. As is clear from the electron micrograph (×20000) shown in FIG. 4, the obtained magnetite particle powder has the following properties:
They were irregularly shaped particles. In addition, this irregularly shaped magnetite particle powder has an average particle diameter of 0.19 μm, an L value of 39.0, and an oil absorption amount of 27 ml/
The weight was 100g and the bulk density was 0.34g/cc. 【table】
図１乃至図４はいずれも電子顕微鏡写真（×
20000）であり、図１及び図２はそれぞれ実施例
１及び実施例４で得られた球型を呈したマグネタ
イト粒子粉末、図３は比較例１で得られた六面体
を呈したマグネタイト粒子粉末、図４は比較例２
で得られた不定形のマグネタイト粒子粉末であ
る。
Figures 1 to 4 are all electron micrographs (×
20000), and FIGS. 1 and 2 show the spherical magnetite particles obtained in Example 1 and Example 4, respectively, and FIG. 3 shows the hexahedral magnetite particles obtained in Comparative Example 1. Figure 4 shows comparative example 2.
It is an amorphous magnetite particle powder obtained in
Claims (1)
Fe2+に対し0.80〜0.99当量の水酸化アルカリとを
反応させて得られた水酸化第一鉄コロイドを含む
第一鉄塩反応水溶液に、30℃〜100℃の温度範囲
で加熱しながら酸素含有ガスを通気することによ
り、上記水酸化第一鉄コロイドから球型を呈した
マグネタイト粒子を生成させる第一段と、該第一
段反応終了後残存Fe2+に対し1.00当量以上の水酸
化アルカリを添加し第一段反応と同条件下で加熱
酸化する第二段との二段階反応から成ることを特
徴とする球型を呈したマグネタイト粒子粉末の製
造法。1 Ferrous salt aqueous solution and the ferrous salt aqueous solution
Oxygen was added to a ferrous salt reaction aqueous solution containing ferrous hydroxide colloid obtained by reacting 0.80 to 0.99 equivalents of alkali hydroxide to Fe 2+ while heating in a temperature range of 30°C to 100°C. A first stage in which spherical magnetite particles are produced from the ferrous hydroxide colloid by aerating the contained gas, and alkali hydroxide in an amount of 1.00 equivalent or more based on the residual Fe 2+ after the first stage reaction is completed. A method for producing magnetite particle powder exhibiting a spherical shape, characterized by comprising a two-step reaction of adding and heating the first step and a second step of heating and oxidizing under the same conditions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58181290A JPS6071529A (en) | 1983-09-28 | 1983-09-28 | Manufacture of spherical magnetite powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58181290A JPS6071529A (en) | 1983-09-28 | 1983-09-28 | Manufacture of spherical magnetite powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6071529A JPS6071529A (en) | 1985-04-23 |
| JPS6251208B2 true JPS6251208B2 (en) | 1987-10-29 |
Family
ID=16098094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58181290A Granted JPS6071529A (en) | 1983-09-28 | 1983-09-28 | Manufacture of spherical magnetite powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6071529A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4774012A (en) * | 1986-01-30 | 1988-09-27 | Ishihara Sangyo Kaisha, Ltd. | Cobalt-containing ferromagnetic iron oxide powder and process for producing the same |
| JPS6366582A (en) * | 1986-09-09 | 1988-03-25 | Toyo Ink Mfg Co Ltd | Method for processing electrostatic charge image |
| JPH0827551B2 (en) * | 1986-10-27 | 1996-03-21 | キヤノン株式会社 | Insulating magnetic capsule toner |
| DE3803940A1 (en) * | 1988-02-10 | 1989-08-24 | Bayer Ag | NEW OXIDATION-STABLE HEAT-RESISTANT IRON-OXIDE-BLACK PIGMENTS, METHOD FOR THE PRODUCTION AND USE THEREOF |
| DE3821342A1 (en) * | 1988-06-24 | 1989-12-28 | Bayer Ag | NEW IRON OXIDE PIGMENTS, METHOD FOR THE PRODUCTION AND USE THEREOF |
| JP2759519B2 (en) * | 1989-09-14 | 1998-05-28 | キヤノン株式会社 | Magnetic toner for developing electrostatic latent images |
| JP2756845B2 (en) * | 1989-12-28 | 1998-05-25 | 戸田工業株式会社 | Hexahedral magnetite particle powder and its manufacturing method |
| JP3438465B2 (en) * | 1996-03-07 | 2003-08-18 | 戸田工業株式会社 | Magnetic iron oxide particles, magnetic iron oxide particle powder for magnetic toner mainly comprising the particles, method for producing the same, and magnetic toner using the magnetic iron oxide particle powder |
| JP5741890B2 (en) * | 2010-03-31 | 2015-07-01 | 戸田工業株式会社 | Black magnetic iron oxide particle powder and method for producing the same |
-
1983
- 1983-09-28 JP JP58181290A patent/JPS6071529A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6071529A (en) | 1985-04-23 |
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