JPS61189607A - Production of magnetic fluid - Google Patents
Production of magnetic fluidInfo
- Publication number
- JPS61189607A JPS61189607A JP60029387A JP2938785A JPS61189607A JP S61189607 A JPS61189607 A JP S61189607A JP 60029387 A JP60029387 A JP 60029387A JP 2938785 A JP2938785 A JP 2938785A JP S61189607 A JPS61189607 A JP S61189607A
- Authority
- JP
- Japan
- Prior art keywords
- surfactant
- magnetic
- superfine particles
- magnetic fluid
- molecule
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/44—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/44—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids
- H01F1/445—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids the magnetic component being a compound, e.g. Fe3O4
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、磁性流体の製造方法に関する。更に詳しくは
、磁性超微粒子からの界面活性剤の脱着を防止せしめた
磁性流体の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a magnetic fluid. More specifically, the present invention relates to a method for producing a magnetic fluid that prevents desorption of a surfactant from magnetic ultrafine particles.
現在市販されている磁性流体は、マグネタイト（Ｆｅ、
０４）の超微粒子にオレイン酸などの界面活性剤を吸着
させたものを溶媒に分散させたものである。従って、超
微粒子と界面活性剤との間の吸引力は、化学的および物
理的吸着力のみであり、溶媒の物理的な振動、温度変化
、溶媒への気体の混入などにより、界面活性剤は超微粒
子から容易に脱着を起し、超微粒子の溶媒への分散性お
よび磁性流体の物理的安定性を悪化させる原因となって
いる。Magnetic fluids currently on the market include magnetite (Fe,
The ultrafine particles of 04) with a surfactant such as oleic acid adsorbed thereon are dispersed in a solvent. Therefore, the attraction force between ultrafine particles and surfactant is only chemical and physical adsorption force, and physical vibration of the solvent, temperature change, mixing of gas into the solvent, etc. It easily desorbs from the ultrafine particles, causing deterioration of the dispersibility of the ultrafine particles in the solvent and the physical stability of the magnetic fluid.
そこで１本発明者は磁性超微粒子からの界面活性剤の脱
着を防止せしめる方法について種々の検討を行なった結
果１分子中に光重合性基を有する界面活性剤を用いるこ
とにより、かかる課題が効果的に解決されることを見出
した。Therefore, the present inventor conducted various studies on methods for preventing the desorption of surfactants from magnetic ultrafine particles, and found that using a surfactant having a photopolymerizable group in one molecule effectively solved this problem. I found that it can be solved.
〔問題点を解決するための手段〕および〔作用〕従って
、本発明は磁性流体の製造方法に係り。SUMMARY OF THE INVENTION Accordingly, the present invention relates to a method of manufacturing a magnetic fluid.
磁性金属または金属化合物の超微粒子を、分子中に光重
合性基を有する界面活性剤を用いて、超音波照射下に水
性媒体または有機溶媒中に分散させ、そこに形成された
コロイド溶液を光照射することにより行われる。Ultrafine particles of magnetic metals or metal compounds are dispersed in an aqueous medium or organic solvent under ultrasonic irradiation using a surfactant having a photopolymerizable group in the molecule, and the colloidal solution formed therein is exposed to light. This is done by irradiation.
超微粒子を形成する磁性の金属または金属化合物として
は、鉄、コバルト、ニッケル、マグネタイト（Ｆａ□０
４）などが用いられ、それの超微粒子の製造は従来法に
従って行われる。Examples of magnetic metals or metal compounds that form ultrafine particles include iron, cobalt, nickel, and magnetite (Fa□0
4) etc. are used, and the production of ultrafine particles thereof is carried out according to conventional methods.
これらの超微粒子は、水などの水性媒体、またはリン酸
や脂肪酸などの高級エステル、更にはヘキサン、オクタ
ン、イソオクタン、ドデカン、ケロシン、流動パラフィ
ンなどの飽和炭化水素などの有機溶媒中に分散させるが
、その際界面活性剤として、例えば次の一般式で示され
るような分子中に光重合性基を有する界面活性剤が用い
られる。These ultrafine particles can be dispersed in an aqueous medium such as water, or a higher ester such as phosphoric acid or fatty acid, or an organic solvent such as a saturated hydrocarbon such as hexane, octane, isooctane, dodecane, kerosene, or liquid paraffin. In this case, as the surfactant, for example, a surfactant having a photopolymerizable group in the molecule as shown by the following general formula is used.
かかる構造を有する界面活性剤は、水溶液中では安定な
分子会合をもち、磁性超微粒子への吸着性のあることが
確められている（後記参考側参照）。It has been confirmed that surfactants having such a structure have stable molecular associations in an aqueous solution and have adsorption properties to magnetic ultrafine particles (see reference side below).
また、媒体に有機溶媒を用いる場合には、媒体は前記の
如き高級エステルであることが望ましい。Further, when an organic solvent is used as the medium, it is desirable that the medium is a higher ester as described above.
これは、界面活性剤分子と媒体との親和性が増すためで
ある。This is because the affinity between surfactant molecules and the medium increases.
界面活性剤の媒体中への分散は、超微粒子の製造後また
は製造の過程において行われる。例えば、マグネタイト
の超微粒子を用いる場合には、マグネタイト、有機溶媒
および通常の分散剤として用いられるより多い量の界面
活性剤を混合したものを、長時間ボールミルで粉砕し、
マグネタイトを超微粒子状に粉砕すると共に、有機溶媒
中に分散せしめる。Dispersion of the surfactant into the medium is performed after or during the manufacturing process of the ultrafine particles. For example, when using ultrafine particles of magnetite, a mixture of magnetite, an organic solvent, and a larger amount of surfactant than is normally used as a dispersant is ground in a ball mill for a long time.
Magnetite is ground into ultrafine particles and dispersed in an organic solvent.
このようにして得られた超微粒子および界面活性剤を含
有する溶液を、例えば周波数２８ＫＨｚの超音波を用い
て、約２時間程度照射する。この超音波照射により、界
面活性剤の超微粒子への吸着が完全に行われるようにな
り、また超微粒子の溶液中への分散性も更に改善される
。なお、この際、光および熱などにより、光重合性基を
有する界面活性剤分子が重合反応しないように留意しな
ければならないに
の超音波照射の後、界面活性剤分子中の光重合性基の重
合が光照射によって行われ、これによって界面活性剤分
子同士が結合される。The solution containing the ultrafine particles and surfactant thus obtained is irradiated with ultrasonic waves having a frequency of 28 KHz, for example, for about 2 hours. This ultrasonic irradiation allows complete adsorption of the surfactant onto the ultrafine particles, and further improves the dispersibility of the ultrafine particles in the solution. At this time, care must be taken to ensure that the surfactant molecules containing photopolymerizable groups do not undergo a polymerization reaction due to light or heat. Polymerization is carried out by light irradiation, thereby bonding the surfactant molecules together.
本発明方法によれば、界面活性剤の磁性超微粒子からの
脱着が有効に防止された磁性流体が得られるようになる
。According to the method of the present invention, a magnetic fluid can be obtained in which desorption of surfactant from magnetic ultrafine particles is effectively prevented.
次に、実施例について本発明を説明する。 Next, the present invention will be explained with reference to examples.
参考例
水２５ｍ１に前記一般式で表わされる界面活性剤０．２
ｇを添加し、この溶液を水浴中で周波数２８ＫＨｚ、出
力５００ｆｆｉ７）超音波振動子を用いて２時間超音波
照射したところ、ＣＭＣ（臨界ミセル濃度）以上で安定
したコロイド溶液が得られた。この界面活性剤の溶液中
での会合状態は、２分子膜構造をとっているものと思わ
れる。Reference example: 0.2 of a surfactant represented by the above general formula in 25 ml of water.
When this solution was irradiated with ultrasonic waves for 2 hours using an ultrasonic vibrator at a frequency of 28 KHz and an output of 500 ffi7) in a water bath, a stable colloidal solution was obtained above the CMC (critical micelle concentration). The association state of this surfactant in the solution appears to be a bilayer membrane structure.
実施例
水２５ｍ１、上記界面活性剤０．２ｇおよび粗製マグネ
タイト（超微粒子凝集物）０．５ｇを３日間攪拌し、参
考例と同様に２時間超音波照射し、その後−昼夜放置し
た。Example 25 ml of water, 0.2 g of the above surfactant, and 0.5 g of crude magnetite (ultrafine particle aggregate) were stirred for 3 days, irradiated with ultrasonic waves for 2 hours in the same manner as in the reference example, and then left to stand day and night.
マグネタイトの微粒子を含んだコロイド溶液と分散しな
いままのマグネタイトの沈澱とが得られたので、コロイ
ド溶液をデカンテーションにより分離した。分離された
コロイド溶液は安定で、磁力に感応した。これらの事実
から、界面活性剤は磁性超微粒子に吸着されているもの
と考えることができる。A colloidal solution containing fine particles of magnetite and undispersed magnetite precipitate were obtained, and the colloidal solution was separated by decantation. The separated colloidal solution was stable and sensitive to magnetic forces. From these facts, it can be considered that the surfactant is adsorbed to the magnetic ultrafine particles.
このようにして得られたコロイド溶液を、波長約２５０
ｎｍの紫外線照射ランプを用いて更に５時間光照射する
と、物理的振動や温度変化に対する安定性がなお一層改
善されたコロイド溶液が得られた。このことは、界面活
性剤分子の重合によって、界面活性剤の磁性超微粒子か
らの脱着が抑えられたためと考えることができる。The colloidal solution obtained in this way is
Further irradiation for 5 hours using a nm ultraviolet irradiation lamp yielded a colloidal solution with even further improved stability against physical vibrations and temperature changes. This can be considered to be because desorption of the surfactant from the magnetic ultrafine particles was suppressed by polymerization of the surfactant molecules.
Claims (1)
光重合性基を有する界面活性剤を用いて、超音波照射下
に水性媒体または有機溶媒中に分散させ、そこに形成さ
れたコロイド溶液を光照射することを特徴とする磁性流
体の製造方法。 ２、金属化合物がマグネタイトである特許請求の範囲第
１項記載の磁性流体の製造方法。 ３、分子中に光重合性基を有する界面活性剤が、一般式 ▲数式、化学式、表等があります▼ で表わされる有機リン酸エステルである特許請求の範囲
第１項記載の磁性流体の製造方法。[Claims] 1. Ultrafine particles of a magnetic metal or metal compound are dispersed in an aqueous medium or an organic solvent under ultrasonic irradiation using a surfactant having a photopolymerizable group in the molecule; 1. A method for producing a magnetic fluid, comprising irradiating a colloidal solution formed with light. 2. The method for producing a magnetic fluid according to claim 1, wherein the metal compound is magnetite. 3. Production of the magnetic fluid according to claim 1, wherein the surfactant having a photopolymerizable group in the molecule is an organic phosphate ester represented by the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60029387A JPS61189607A (en) | 1985-02-19 | 1985-02-19 | Production of magnetic fluid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60029387A JPS61189607A (en) | 1985-02-19 | 1985-02-19 | Production of magnetic fluid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61189607A true JPS61189607A (en) | 1986-08-23 |
| JPH0473601B2 JPH0473601B2 (en) | 1992-11-24 |
Family
ID=12274725
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60029387A Granted JPS61189607A (en) | 1985-02-19 | 1985-02-19 | Production of magnetic fluid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61189607A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63164405A (en) * | 1986-12-26 | 1988-07-07 | Tdk Corp | Magnetic fluid |
| DE19624426A1 (en) * | 1996-06-19 | 1998-01-02 | Christian Bergemann | Magnetic particle for transport of diagnostic or therapeutic agent |
| US6180226B1 (en) | 1996-08-01 | 2001-01-30 | Loctite (R&D) Limited | Method of forming a monolayer of particles, and products formed thereby |
| US6402876B1 (en) | 1997-08-01 | 2002-06-11 | Loctite (R&D) Ireland | Method of forming a monolayer of particles, and products formed thereby |
| US6977025B2 (en) | 1996-08-01 | 2005-12-20 | Loctite (R&D) Limited | Method of forming a monolayer of particles having at least two different sizes, and products formed thereby |
-
1985
- 1985-02-19 JP JP60029387A patent/JPS61189607A/en active Granted
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63164405A (en) * | 1986-12-26 | 1988-07-07 | Tdk Corp | Magnetic fluid |
| DE19624426A1 (en) * | 1996-06-19 | 1998-01-02 | Christian Bergemann | Magnetic particle for transport of diagnostic or therapeutic agent |
| US6180226B1 (en) | 1996-08-01 | 2001-01-30 | Loctite (R&D) Limited | Method of forming a monolayer of particles, and products formed thereby |
| US6977025B2 (en) | 1996-08-01 | 2005-12-20 | Loctite (R&D) Limited | Method of forming a monolayer of particles having at least two different sizes, and products formed thereby |
| US6402876B1 (en) | 1997-08-01 | 2002-06-11 | Loctite (R&D) Ireland | Method of forming a monolayer of particles, and products formed thereby |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0473601B2 (en) | 1992-11-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |