JP2005123454A - Method of manufacturing ferrofluid, and ferrofluid - Google Patents
Method of manufacturing ferrofluid, and ferrofluid Download PDFInfo
- Publication number
- JP2005123454A JP2005123454A JP2003357892A JP2003357892A JP2005123454A JP 2005123454 A JP2005123454 A JP 2005123454A JP 2003357892 A JP2003357892 A JP 2003357892A JP 2003357892 A JP2003357892 A JP 2003357892A JP 2005123454 A JP2005123454 A JP 2005123454A
- Authority
- JP
- Japan
- Prior art keywords
- solvent
- magnetic fluid
- boiling point
- fine particles
- metal fine
- 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.)
- Withdrawn
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 239000011554 ferrofluid Substances 0.000 title abstract description 5
- 239000002904 solvent Substances 0.000 claims abstract description 116
- 239000011553 magnetic fluid Substances 0.000 claims abstract description 64
- 238000009835 boiling Methods 0.000 claims abstract description 57
- 239000002245 particle Substances 0.000 claims abstract description 32
- 239000004094 surface-active agent Substances 0.000 claims abstract description 26
- 150000002902 organometallic compounds Chemical class 0.000 claims abstract description 23
- 239000012046 mixed solvent Substances 0.000 claims abstract description 10
- 150000001875 compounds Chemical class 0.000 claims abstract description 9
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- 239000002184 metal Substances 0.000 claims description 48
- 229910052751 metal Inorganic materials 0.000 claims description 48
- 239000010419 fine particle Substances 0.000 claims description 46
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 33
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 14
- 229910017052 cobalt Inorganic materials 0.000 claims description 13
- 239000010941 cobalt Substances 0.000 claims description 13
- 239000003350 kerosene Substances 0.000 claims description 11
- 238000010992 reflux Methods 0.000 claims description 11
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 10
- DIOQZVSQGTUSAI-UHFFFAOYSA-N decane Chemical compound CCCCCCCCCC DIOQZVSQGTUSAI-UHFFFAOYSA-N 0.000 claims description 10
- 230000005415 magnetization Effects 0.000 claims description 8
- 239000002923 metal particle Substances 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 7
- AFABGHUZZDYHJO-UHFFFAOYSA-N 2-Methylpentane Chemical compound CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 claims description 6
- 229910001111 Fine metal Inorganic materials 0.000 claims description 6
- 239000001293 FEMA 3089 Substances 0.000 claims description 5
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 claims description 3
- 239000006249 magnetic particle Substances 0.000 claims description 3
- 239000012530 fluid Substances 0.000 claims 1
- 239000000696 magnetic material Substances 0.000 claims 1
- 239000013528 metallic particle Substances 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 17
- 239000002609 medium Substances 0.000 description 14
- 238000005979 thermal decomposition reaction Methods 0.000 description 11
- 239000000243 solution Substances 0.000 description 6
- JNYAEWCLZODPBN-JGWLITMVSA-N (2r,3r,4s)-2-[(1r)-1,2-dihydroxyethyl]oxolane-3,4-diol Chemical compound OC[C@@H](O)[C@H]1OC[C@H](O)[C@H]1O JNYAEWCLZODPBN-JGWLITMVSA-N 0.000 description 5
- 229940084778 1,4-sorbitan Drugs 0.000 description 5
- 238000000197 pyrolysis Methods 0.000 description 5
- 238000003917 TEM image Methods 0.000 description 4
- 238000004821 distillation Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 2
- -1 fatty acid esters Chemical class 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 2
- 239000001593 sorbitan monooleate Substances 0.000 description 2
- MPCAJMNYNOGXPB-UHFFFAOYSA-N 1,5-Anhydro-mannit Natural products OCC1OCC(O)C(O)C1O MPCAJMNYNOGXPB-UHFFFAOYSA-N 0.000 description 1
- MPCAJMNYNOGXPB-SLPGGIOYSA-N 1,5-anhydro-D-glucitol Chemical compound OC[C@H]1OC[C@H](O)[C@@H](O)[C@@H]1O MPCAJMNYNOGXPB-SLPGGIOYSA-N 0.000 description 1
- DINAZWYMBSZRQF-UHFFFAOYSA-N 2,3-dihydroxypropyl octadecanoate propane-1,2-diol Chemical compound CC(O)CO.CC(O)CO.CC(O)CO.CC(O)CO.CC(O)CO.CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO.CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO.CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO.CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO.CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO DINAZWYMBSZRQF-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 241000220317 Rosa Species 0.000 description 1
- SBFLFRSXNYZPEH-YMKFFAQDSA-N [(2r)-3-[(2s)-3-[(2s)-2-butanoyloxy-3-[(2r)-2-hydroxy-3-[(2s)-3-[(2r)-3-hydroxy-2-pentanoyloxypropoxy]-2-propanoyloxypropoxy]propoxy]propoxy]-2-hydroxypropoxy]-2-hydroxypropyl] octadecanoate Chemical compound CCCCCCCCCCCCCCCCCC(=O)OC[C@H](O)COC[C@H](O)COC[C@H](OC(=O)CCC)COC[C@H](O)COC[C@H](OC(=O)CC)COC[C@@H](CO)OC(=O)CCCC SBFLFRSXNYZPEH-YMKFFAQDSA-N 0.000 description 1
- AZPFEYANVWPOHJ-CLFAGFIQSA-N [2-hydroxy-3-[2-hydroxy-3-[(Z)-octadec-9-enoyl]oxypropoxy]propyl] (Z)-octadec-9-enoate Chemical compound CCCCCCCC\C=C/CCCCCCCC(=O)OCC(O)COCC(O)COC(=O)CCCCCCC\C=C/CCCCCCCC AZPFEYANVWPOHJ-CLFAGFIQSA-N 0.000 description 1
- ZQHDBIHAVWMCHD-UHFFFAOYSA-N [2-hydroxy-3-[3-[3-[3-[3-[3-[3-[3-[3-(2-hydroxy-3-octadecanoyloxypropoxy)-2-octadecanoyloxypropoxy]-2-octadecanoyloxypropoxy]-2-octadecanoyloxypropoxy]-2-octadecanoyloxypropoxy]-2-octadecanoyloxypropoxy]-2-octadecanoyloxypropoxy]-2-octadecanoyloxypropoxy]-2-octadecanoyloxypropoxy]propyl] octadecanoate Chemical compound CCCCCCCCCCCCCCCCCC(=O)OCC(O)COCC(COCC(COCC(COCC(COCC(COCC(COCC(COCC(COCC(O)COC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC ZQHDBIHAVWMCHD-UHFFFAOYSA-N 0.000 description 1
- BKZCZANSHGDPSH-KTKRTIGZSA-N [3-(2,3-dihydroxypropoxy)-2-hydroxypropyl] (z)-octadec-9-enoate Chemical compound CCCCCCCC\C=C/CCCCCCCC(=O)OCC(O)COCC(O)CO BKZCZANSHGDPSH-KTKRTIGZSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 125000002524 organometallic group Chemical group 0.000 description 1
- 229920000223 polyglycerol Polymers 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229940035049 sorbitan monooleate Drugs 0.000 description 1
- 239000001587 sorbitan monostearate Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 235000021122 unsaturated fatty acids Nutrition 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Landscapes
- Soft Magnetic Materials (AREA)
Abstract
Description
本発明は、磁性流体の製造方法および磁性流体に関する。 The present invention relates to a method for producing a magnetic fluid and a magnetic fluid.
磁性流体とは、例えば鉄やコバルトの金属微粒子の表面を界面活性剤で処理し、油類や水等の媒体中にコロイド状に分散させたものである。このような磁性流体は角度センサー、傾斜センサー、回転軸のシール、振動系のダンパー等、多くの場所で使用されており、磁性流体の特性を改良する研究が進められている。例えば磁性流体の飽和磁化を大きくする研究では、コバルトの金属微粒子と界面活性剤と炭素系触媒とからなる磁性流体に関する技術が開示されている（特許文献１）。この技術では、界面活性剤を溶解させた炭化水素媒体中に金属カルボニルを加えて加熱して熱分解することにより、平均粒子径が７〜１２ｎｍの金属微粒子を高濃度で含む磁性流体を得ることができる。 The magnetic fluid is obtained by, for example, treating the surface of fine metal particles such as iron or cobalt with a surfactant and dispersing it in a colloidal form in a medium such as oil or water. Such a magnetic fluid is used in many places such as an angle sensor, a tilt sensor, a rotary shaft seal, and a vibration damper, and researches to improve the characteristics of the magnetic fluid are underway. For example, in a study to increase the saturation magnetization of a magnetic fluid, a technique relating to a magnetic fluid composed of cobalt metal fine particles, a surfactant, and a carbon-based catalyst is disclosed (Patent Document 1). In this technique, a magnetic fluid containing a high concentration of fine metal particles having an average particle diameter of 7 to 12 nm is obtained by adding metal carbonyl to a hydrocarbon medium in which a surfactant is dissolved and heating and thermally decomposing it. Can do.
ところで、磁性流体中の金属微粒子は、外部の磁力に引き付けられて媒体とともに移動する。しかしながら、その磁力が強力な場合、媒体中に均一に分散していた金属微粒子が磁力に引き付けられ、媒体中で金属微粒子の濃度勾配が生じ、その結果、磁性流体に磁気勾配が生じてしまう。また、磁性流体は重力の影響も受けるので、同様に磁気勾配が生じることがある。その他、金属微粒子同士の引力（ファンデスワールス力）により、金属微粒子が凝集することがある。 By the way, the metal fine particles in the magnetic fluid are attracted by an external magnetic force and move together with the medium. However, when the magnetic force is strong, the metal fine particles uniformly dispersed in the medium are attracted to the magnetic force, and a concentration gradient of the metal fine particles is generated in the medium. As a result, a magnetic gradient is generated in the magnetic fluid. In addition, since magnetic fluid is also affected by gravity, a magnetic gradient may occur in the same manner. In addition, metal fine particles may agglomerate due to attractive force (van Desworth force) between the metal fine particles.
本発明は、このような技術的課題に基づいてなされたもので、安定性に優れた磁気特性を有する磁性流体等を提供することを目的とする。 The present invention has been made based on such a technical problem, and an object thereof is to provide a magnetic fluid or the like having magnetic properties with excellent stability.
本発明者等が上記の課題について鋭意検討を行った結果、金属磁性流体を界面活性剤存在下の溶液中で製造する際に、生成される金属微粒子の粒径は、溶液に分散した有機金属化合物の反応温度によって決まることを見出し、さらにその反応温度は、溶液の還流温度によって決まることを見出した。そして、これには、沸点の異なる二種類の溶媒を混合し、これを用いるのが好ましいことを見出した。二種類の溶媒を混合することにより、低沸点側溶媒の存在により溶媒を高沸点溶媒のみで行った場合よりも低い温度で還流が始まる。このとき、有機金属化合物が熱分解されて、金属微粒子が生成するのである。そして、溶媒中の低沸点溶媒の蒸留が終わると、溶媒の温度は徐々に上昇する。熱分解反応より生成された金属微粒子は、溶媒中に添加されていた界面活性剤により高沸点溶媒中に分散し、磁性流体が得られるのである。 As a result of intensive studies on the above problems by the present inventors, when the metal magnetic fluid is produced in a solution in the presence of a surfactant, the particle size of the metal fine particles produced is an organometallic dispersed in the solution. It was found that the reaction temperature depends on the reaction temperature of the compound, and that the reaction temperature depends on the reflux temperature of the solution. And for this, it discovered that it was preferable to mix and use two types of solvents from which boiling points differ. By mixing the two kinds of solvents, the reflux starts at a lower temperature than when the solvent is used only with the high boiling point solvent due to the presence of the low boiling point side solvent. At this time, the organometallic compound is thermally decomposed to produce fine metal particles. When the distillation of the low boiling point solvent in the solvent ends, the temperature of the solvent gradually increases. The metal fine particles generated by the thermal decomposition reaction are dispersed in the high boiling point solvent by the surfactant added in the solvent, and a magnetic fluid is obtained.
このような知見に基づいてなされた本発明は、溶媒中において、有機金属化合物および界面活性剤を加熱して磁性流体を製造するに際し、溶媒を、第１の溶媒と第１の溶媒より高い沸点を有する第２の溶媒を含む混合溶媒とし、第１の溶媒と第２の溶媒の混合比を調整することで、製造される磁性流体に含まれる磁性体粒子の粒径を制御するものである。これにより、磁性体粒子の粒径を小さくすることが可能となる。粒子径が小さい金属微粒子は溶媒中に均一に分散するので、磁性流体の安定性が向上する。 The present invention made on the basis of such knowledge, when producing a magnetic fluid by heating an organometallic compound and a surfactant in a solvent, the solvent has a higher boiling point than the first solvent and the first solvent. The particle size of the magnetic particles contained in the magnetic fluid to be produced is controlled by adjusting the mixing ratio of the first solvent and the second solvent. . This makes it possible to reduce the particle size of the magnetic particles. Since the metal fine particles having a small particle size are uniformly dispersed in the solvent, the stability of the magnetic fluid is improved.
また、本発明の磁性流体の製造方法は、第１の溶媒と、第１の溶媒より高い沸点を有する第２の溶媒と、界面活性剤と、有機金属化合物とを混合して混合物を得た後、この混合物を加熱して磁性流体を製造することを特徴とする方法である。
このとき、第１の溶媒の沸点は５０℃以上８０℃以下であり、第２の溶媒の沸点は１５０℃以上２７０℃以下であることが好ましい。具体例としては、第１の溶媒は、ヘキサン、シクロヘキサン、イソヘキサンからなる群より選ばれる少なくとも１種の化合物であり、第２の溶媒は、ケロシン、デカン、テレピン油からなる群より選ばれる少なくとも１種の化合物である。
In addition, in the method for producing a magnetic fluid of the present invention, a first solvent, a second solvent having a boiling point higher than that of the first solvent, a surfactant, and an organometallic compound were mixed to obtain a mixture. Thereafter, the mixture is heated to produce a magnetic fluid.
At this time, the boiling point of the first solvent is preferably 50 ° C. or higher and 80 ° C. or lower, and the boiling point of the second solvent is preferably 150 ° C. or higher and 270 ° C. or lower. As a specific example, the first solvent is at least one compound selected from the group consisting of hexane, cyclohexane, and isohexane, and the second solvent is at least one selected from the group consisting of kerosene, decane, and turpentine oil. A kind of compound.
なお、この磁性流体の製造方法では、第２の溶媒の沸点より低い温度で有機金属化合物を熱分解反応させて金属微粒子を生成させ、第１の溶媒を還流除去することにより界面活性剤を介して第２の溶媒中へ金属微粒子を分散させた磁性流体を得ることができる。
この磁性流体の製造方法では有機金属化合物の金属はコバルトまたは鉄であり、得られる磁性流体の金属微粒子の平均粒径が７ｎｍ未満であることが好ましい。
In this method for producing a magnetic fluid, the organometallic compound is pyrolyzed at a temperature lower than the boiling point of the second solvent to form metal fine particles, and the first solvent is removed by refluxing. Thus, a magnetic fluid in which metal fine particles are dispersed in the second solvent can be obtained.
In this method of producing a magnetic fluid, the metal of the organometallic compound is cobalt or iron, and the average particle size of the metal particles of the obtained magnetic fluid is preferably less than 7 nm.
本発明は、有機金属化合物および界面活性剤を分散させた媒体を加熱し、所定の温度で有機金属化合物を熱分解反応させることで金属微粒子を生成させるとともに、媒体の一部を還流除去することにより、界面活性剤を介して媒体の残部中へ当該金属微粒子を分散させた磁性流体を得ることを特徴とすることもできる。所定の温度で媒体（の一部）を還流させると、有機金属化合物が熱分解されて、金属微粒子が生成される。さらに加熱を続け、媒体（の一部）の蒸留が終わると、媒体の残部の温度は徐々に上昇し、最終的に、界面活性剤により、有機金属化合物が、分散媒として機能する媒体中に分散し、磁性流体が得られるのである。 The present invention heats a medium in which an organometallic compound and a surfactant are dispersed, and thermally decomposes the organometallic compound at a predetermined temperature to generate metal fine particles, and part of the medium is refluxed and removed. Thus, it is possible to obtain a magnetic fluid in which the metal fine particles are dispersed in the remainder of the medium via a surfactant. When the medium (a part of the medium) is refluxed at a predetermined temperature, the organometallic compound is thermally decomposed to generate fine metal particles. When the heating is continued and the distillation of the medium (a part of the medium) is finished, the temperature of the remainder of the medium gradually increases, and finally, the surfactant causes the organometallic compound to enter the medium functioning as the dispersion medium. It is dispersed and a magnetic fluid is obtained.
このような方法によって製造される本発明の磁性流体は、溶媒中にコバルトおよび／または鉄の金属微粒子が分散した磁性流体であって、金属微粒子の平均粒径が７ｎｍ未満であることを特徴とするものである。このような小さな粒子径の金属微粒子は安定して溶媒中に分散する。なお、この磁性流体は飽和磁化が７０ｍＴ以上であることが好ましい。 The magnetic fluid of the present invention produced by such a method is a magnetic fluid in which metal fine particles of cobalt and / or iron are dispersed in a solvent, and the average particle size of the metal fine particles is less than 7 nm. To do. Such fine metal particles having a small particle diameter are stably dispersed in the solvent. This magnetic fluid preferably has a saturation magnetization of 70 mT or more.
また本発明の磁性流体は、第１の溶媒と第１の溶媒より高い沸点を有する第２の溶媒とを含む混合溶媒中において有機金属化合物から分解生成された金属微粒子と、界面活性剤とを含むことを特徴とするものである。第１の溶媒と第２の溶媒中で生成された金属微粒子は、粒子径が小さく、安定して溶媒中に分散する。なお、第２の溶媒は、例えばケロシン、デカン、テレピン油からなる群より選ばれる少なくとも１種の化合物であり、金属微粒子は界面活性剤により第２の溶媒中で分散する。 In addition, the magnetic fluid of the present invention comprises a fine particle decomposed and generated from an organometallic compound in a mixed solvent containing a first solvent and a second solvent having a boiling point higher than that of the first solvent, and a surfactant. It is characterized by including. The metal fine particles produced in the first solvent and the second solvent have a small particle size and are stably dispersed in the solvent. The second solvent is at least one compound selected from the group consisting of kerosene, decane, and turpentine oil, for example, and the metal fine particles are dispersed in the second solvent by a surfactant.
本発明によれば、安定性に優れた磁気特性を有する磁性流体を得ることができる。 According to the present invention, a magnetic fluid having magnetic properties with excellent stability can be obtained.
本発明では、沸点が低い第１の溶媒（以下、低沸点溶媒）と、第１の溶媒より高い沸点を有する第２の溶媒（以下、高沸点溶媒）を混合し、混合溶媒に有機金属化合物および界面活性剤を添加し、この混合物を加熱することにより、磁性流体を得ることができる。 In the present invention, a first solvent having a low boiling point (hereinafter referred to as a low boiling point solvent) and a second solvent having a boiling point higher than that of the first solvent (hereinafter referred to as a high boiling point solvent) are mixed, and an organometallic compound is mixed into the mixed solvent. By adding a surfactant and heating the mixture, a ferrofluid can be obtained.
有機金属化合物としては、加熱により分解されて磁性を有する金属微粒子を生成することが可能な化合物であり、例えばコバルトカルボニル等の有機コバルトや鉄等カルボニルの有機鉄を挙げることができる。例えばコバルトカルボニルであるオクタカルボニルコバルト（Ｃｏ2（ＣＯ）8）からコバルトの金属微粒子を得る際の熱分解反応の化学式は以下のようになる。
２Ｃｏ2（ＣＯ）8→Ｃｏ4（ＣＯ）12＋４ＣＯ
Ｃｏ4（ＣＯ）12→４Ｃｏ＋２ＣＯ
The organometallic compound is a compound that can be decomposed by heating to generate magnetic metal fine particles, and examples thereof include organic cobalt such as cobalt carbonyl and organic iron such as carbonyl such as iron. For example, the chemical formula of the thermal decomposition reaction for obtaining cobalt metal fine particles from octacarbonylcobalt (Co 2 (CO) 8 ), which is cobalt carbonyl, is as follows.
2Co 2 (CO) 8 → Co 4 (CO) 12 + 4CO
Co 4 (CO) 12 → 4Co + 2CO
低沸点溶媒の沸点は５０℃以上８０℃以下であることが好ましい。低沸点溶媒として、例えばヘキサン、シクロヘキサン、イソヘキサン、およびこれらの２種以上の混合物等を挙げることができる。
高沸点溶媒の沸点は１５０℃以上２７０℃以下であることが好ましい。高沸点溶媒として、例えばケロシン、デカン、テレピン油、およびこれらの２種以上の混合物等を挙げることができる。この高沸点溶媒は主として最終的に得られる磁性流体の溶媒となるため、粘性が低く、揮発性の低いものであることが好ましく、特にケロシンが好ましい。
The boiling point of the low boiling point solvent is preferably 50 ° C. or higher and 80 ° C. or lower. Examples of the low boiling point solvent include hexane, cyclohexane, isohexane, and a mixture of two or more thereof.
The boiling point of the high boiling point solvent is preferably 150 ° C. or higher and 270 ° C. or lower. Examples of the high boiling point solvent include kerosene, decane, turpentine oil, and a mixture of two or more thereof. Since this high-boiling solvent mainly serves as a solvent for the finally obtained magnetic fluid, it is preferably a low-viscosity and low-volatility solvent, particularly kerosene.
低沸点溶媒と高沸点溶媒との混合比率は、最終的に得られる磁性流体における金属微粒子の平均粒径に影響を及ぼす。具体的には、高沸点溶媒の添加量と比較して低沸点溶媒の割合が多いほど、得られる金属微粒子の平均粒径は小さくなる。したがって、希望する平均粒子径に応じて、混合比率は調整することができる。なお、平均粒子径が７ｎｍ未満であると、磁性流体の安定性が優れ大変好ましい。平均粒子径は７ｎｍ未満のものを得るには、低沸点溶媒を高沸点溶媒と同じ重量で、またはそれ以上の重量で混合すると、平均粒径は約７ｎｍ未満となりやすい。例えば低沸点溶媒がヘキサン、高沸点溶媒がケロシンの場合、同じ重量比率で混合すると、金属微粒子の平均粒径が約４．５ｎｍとなる。 The mixing ratio of the low boiling point solvent and the high boiling point solvent affects the average particle diameter of the metal fine particles in the finally obtained magnetic fluid. Specifically, the average particle diameter of the obtained metal fine particles becomes smaller as the proportion of the low boiling point solvent is larger than the amount of the high boiling point solvent added. Therefore, the mixing ratio can be adjusted according to the desired average particle size. In addition, when the average particle size is less than 7 nm, the stability of the magnetic fluid is excellent, which is very preferable. In order to obtain an average particle size of less than 7 nm, the average particle size tends to be less than about 7 nm when a low-boiling solvent is mixed with the same weight as or higher than the high-boiling solvent. For example, when the low-boiling point solvent is hexane and the high-boiling point solvent is kerosene, when mixed at the same weight ratio, the average particle size of the metal fine particles is about 4.5 nm.
また金属微粒子を溶媒中に分散させるための界面活性剤としては、従来使用されているものを適宜使用することができ、例えば、デカグリセリルペンタオレート、デカグリセリルペンタステアレート、デカグリセリルペンタイソステアレート、デカグリセリルヘプタステアレート、デカグリセリルヘプタイソステアレート、デカグリセリルヘプタオレート、デカグリセリルデカイソステアレート、デカグリセリルデカステアレート、デカグリセリルデカオレート、ジグリセリルモノオレート、ジグリセリルジオレート、テトラグリセリルトリステアレート、テトラグリセリルテトラステアレート、テトラグリセリルペンタオレート、ヘキサグリセリルトリステアレート、ヘキサグリセリルペンタオレート、ヘキサグリセリルペンタステアレート等のポリグリセリン脂肪酸エステルを挙げることができる。また、１，５−ソルビタンモノオレート、１，４−ソルビタンモノオレート、１，４−ソルビタンモノステアレート、１，４−ソルビタンモノイソステアレート、１，４−ソルビタンセスキオレート、１，４−ソルビタンセスキイソステアレート等のソルビタン不飽和脂肪酸エステルを挙げることができる。 In addition, as a surfactant for dispersing metal fine particles in a solvent, conventionally used surfactants can be appropriately used. For example, decaglyceryl pentaoleate, decaglyceryl pentastearate, decaglyceryl pentaisostearate , Decaglyceryl hepta stearate, decaglyceryl heptaisostearate, decaglyceryl heptaoleate, decaglyceryl decaisostearate, decaglyceryl decastearate, decaglyceryl dekaorate, diglyceryl monooleate, diglyceryl dioleate, tetraglyceryl tri Stearate, tetraglyceryl tetrastearate, tetraglyceryl pentaoleate, hexaglyceryl tristearate, hexaglyceryl pentaoleate, hexaglyceryl pentastearate Polyglycerol fatty acid esters and the like can be mentioned. Also, 1,5-sorbitan monooleate, 1,4-sorbitan monooleate, 1,4-sorbitan monostearate, 1,4-sorbitan monoisostearate, 1,4-sorbitan sesquioleate, 1,4-sorbitan Examples include sorbitan unsaturated fatty acid esters such as sesquiisostearate.
本発明では、低沸点溶媒と高沸点溶媒とを混合し、この混合された溶媒へ界面活性剤および有機金属化合物を添加し、加熱する。すると、低沸点溶媒の存在により溶媒を高沸点溶媒のみで行った場合よりも低い温度で還流が始まる。このとき、有機金属化合物が熱分解されて、金属微粒子が生成する。溶媒中の低沸点溶媒の蒸留が終わると、溶媒の温度は徐々に上昇する。熱分解反応より生成された金属微粒子は、溶媒中に添加されていた界面活性剤により溶媒中に分散し、磁性流体が得られる。なお低沸点溶媒は反応が終了した後、殆ど還流除去されて溶媒中に残っていない。一方、高沸点溶媒は蒸発せずに磁性流体の溶媒として残る。 In the present invention, a low boiling point solvent and a high boiling point solvent are mixed, a surfactant and an organometallic compound are added to the mixed solvent, and the mixture is heated. Then, due to the presence of the low-boiling solvent, the refluxing starts at a lower temperature than when the solvent is used only with the high-boiling solvent. At this time, the organometallic compound is thermally decomposed to produce metal fine particles. When the distillation of the low boiling point solvent in the solvent is completed, the temperature of the solvent gradually increases. The metal fine particles generated by the thermal decomposition reaction are dispersed in the solvent by the surfactant added in the solvent, and a magnetic fluid is obtained. Note that the low boiling point solvent is hardly removed by refluxing after the reaction is completed and does not remain in the solvent. On the other hand, the high boiling point solvent does not evaporate and remains as a solvent for the magnetic fluid.
このように高沸点溶媒に低沸点溶媒を加えた混合溶媒を用いて加熱し、熱分解反応を行っているので、高沸点溶媒のみで行った場合よりも低い温度で還流が始まり熱分解反応が進む。その結果、金属微粒子の平均粒子径が、溶媒として高沸点溶媒のみを用いた場合よりも小さなものとなり、例えば１０ｎｍ以下２ｎｍ以上となり、溶媒として低沸点溶媒の含有量を増やせば７ｎｍ未満となる。このようにして得られた磁性流体では、従来の磁性流体と比較して金属微粒子が溶媒中へより均一に分散する。したがって、外部からの磁力、重力、金属微粒子間の引力等の影響を受けにくい、安定した磁性流体を得ることができる。また、この磁性流体の飽和磁化も７０ｍＴ以上となるように粒子径を調節することが好ましい。
なお、本発明の主旨を逸脱しない限り、上記実施の形態で挙げた構成を取捨選択したり、他の構成に適宜変更することが可能である。
As described above, since the thermal decomposition reaction is performed by using the mixed solvent obtained by adding the low boiling point solvent to the high boiling point solvent, the reflux starts at a lower temperature than when the high boiling point solvent is used alone, and the thermal decomposition reaction is started. move on. As a result, the average particle size of the metal fine particles becomes smaller than that when only the high boiling point solvent is used as the solvent, for example, 10 nm or less and 2 nm or more. If the content of the low boiling point solvent as the solvent is increased, it becomes less than 7 nm. In the magnetic fluid thus obtained, the metal fine particles are more uniformly dispersed in the solvent as compared with the conventional magnetic fluid. Therefore, it is possible to obtain a stable magnetic fluid that is hardly affected by external magnetic force, gravity, attractive force between metal fine particles, and the like. Further, it is preferable to adjust the particle diameter so that the saturation magnetization of the magnetic fluid is 70 mT or more.
It should be noted that the configurations described in the above embodiments can be selected or changed to other configurations as appropriate without departing from the gist of the present invention.
（実施例１）
低沸点溶媒として沸点が６９℃のヘキサン１３２ｇと、高沸点溶媒として沸点が１８０〜２６０℃のケロシンを１３２ｇとを混合し、この混合溶媒に界面活性剤としてデカグリセリルヘプタオレート６０ｇを溶解させた。この溶解液を冷却器、温度計、攪拌装置を取付けた三口フラスコに入れた。この三口フラスコにオクタカルボニルコバルト（Ｃｏ2（ＣＯ）8）を５００ｇ添加した。この混合溶液を攪拌しながら、加熱装置（マントルヒーター）で徐々に加熱し、攪拌しながらコバルトカルボニルの熱分解を行った。このとき、分解により生じるＣＯが発生した。熱分解時の反応温度は９０℃であった。熱分解反応の終了後、溶液の温度は上昇し、１６０℃になったところで終了して冷却し、黒色の磁性流体を得ることができた。
得られた磁性流体の飽和磁化は８０ｍＴ、金属微粒子の平均粒径はＴＥＭ観察により測定したところ、約４．５ｎｍであった。なお、分析の結果、この磁性流体の溶媒には低沸点溶媒のヘキサンは残っていなかった。得られた磁性流体中のコバルト微粒子のＴＥＭ像を図１に示す。
(Example 1)
132 g of hexane having a boiling point of 69 ° C. as a low boiling solvent and 132 g of kerosene having a boiling point of 180 to 260 ° C. as a high boiling solvent were mixed, and 60 g of decaglyceryl heptaoleate as a surfactant was dissolved in this mixed solvent. This solution was put in a three-necked flask equipped with a cooler, a thermometer, and a stirring device. To this three-necked flask, 500 g of octacarbonylcobalt (Co 2 (CO) 8 ) was added. While stirring this mixed solution, it heated gradually with the heating apparatus (mantle heater), and thermal decomposition of cobalt carbonyl was performed, stirring. At this time, CO generated by decomposition was generated. The reaction temperature during pyrolysis was 90 ° C. After the completion of the pyrolysis reaction, the temperature of the solution rose. When the temperature reached 160 ° C., the solution was finished and cooled to obtain a black magnetic fluid.
The saturation magnetization of the obtained magnetic fluid was 80 mT, and the average particle size of the metal fine particles was about 4.5 nm as measured by TEM observation. As a result of analysis, hexane, which is a low boiling point solvent, did not remain in the magnetic fluid solvent. A TEM image of the cobalt fine particles in the magnetic fluid obtained is shown in FIG.
（実施例２）
実施例１における低沸点溶媒のヘキサンの量を１０８ｇとした以外は実施例１と同様に試験を行った。なお、熱分解時の反応温度は１０５℃であった。得られた磁性流体の飽和磁化は１２７ｍＴ、金属微粒子の平均粒径は約６．８ｎｍであった。
(Example 2)
The test was performed in the same manner as in Example 1 except that the amount of hexane as the low boiling point solvent in Example 1 was changed to 108 g. The reaction temperature at the time of thermal decomposition was 105 ° C. The saturation magnetic magnetization of the obtained magnetic fluid was 127 mT, and the average particle diameter of the metal fine particles was about 6.8 nm.
（実施例３）
実施例１における低沸点溶媒のヘキサンの量を８８ｇとした以外は実施例１と同様に試験を行った。なお、熱分解時の反応温度は１１２℃であった。得られた磁性流体の飽和磁化は１３２ｍＴ、金属微粒子の平均粒径は約７．７ｎｍであった。
(Example 3)
The test was performed in the same manner as in Example 1 except that the amount of hexane as the low boiling point solvent in Example 1 was 88 g. The reaction temperature during the thermal decomposition was 112 ° C. The obtained magnetic fluid had a saturation magnetization of 132 mT, and the average particle size of the metal fine particles was about 7.7 nm.
（実施例４）
実施例１における低沸点溶媒のヘキサンの量を５７ｇとした以外は実施例１と同様に試験を行った。なお、熱分解時の反応温度は１２５℃であった。得られた磁性流体の飽和磁化は１２９ｍＴ、金属微粒子の平均粒径は約９．６ｎｍであった。得られた磁性流体中のコバルト微粒子のＴＥＭ像を図２に示す。
Example 4
The test was performed in the same manner as in Example 1 except that the amount of hexane as the low boiling point solvent in Example 1 was changed to 57 g. In addition, the reaction temperature at the time of thermal decomposition was 125 degreeC. The obtained magnetic fluid had a saturation magnetization of 129 mT, and the average particle size of the metal fine particles was about 9.6 nm. A TEM image of the cobalt fine particles in the obtained magnetic fluid is shown in FIG.
実施例１〜４の結果に基づき、ケロシンのヘキサンに対する混合比率と、熱分解時の反応温度および還流温度との関係を図３に示す。また熱分解時の反応温度と得られた金属微粒子の平均粒径との関係を図４に示す。図３に示すように、ケロシンの割合が増える、すなわちヘキサンの割合が減るほど、還流温度が高くなり、また熱分解時の反応温度が高くなることがわかる。このように反応温度と金属微粒子の平均粒径とは相関関係があり、反応温度が高いほど平均粒径が大きくなることがわかる。したがって、溶媒の混合比率を適宜設定し、還流温度を制御し、すなわち反応温度を制御することで、平均粒径を調節することができることがわかる。 Based on the results of Examples 1 to 4, the relationship between the mixing ratio of kerosene to hexane and the reaction temperature and reflux temperature during pyrolysis is shown in FIG. FIG. 4 shows the relationship between the reaction temperature during pyrolysis and the average particle size of the obtained metal fine particles. As shown in FIG. 3, it can be seen that as the proportion of kerosene increases, that is, the proportion of hexane decreases, the reflux temperature increases and the reaction temperature during pyrolysis increases. Thus, there is a correlation between the reaction temperature and the average particle diameter of the metal fine particles, and it can be seen that the average particle diameter increases as the reaction temperature increases. Therefore, it can be seen that the average particle size can be adjusted by appropriately setting the mixing ratio of the solvent and controlling the reflux temperature, that is, controlling the reaction temperature.
Claims (11)
前記溶媒を、第１の溶媒と当該第１の溶媒より高い沸点を有する第２の溶媒を含む混合溶媒とし、
前記第１の溶媒と前記第２の溶媒の混合比を調整することで、製造される前記磁性流体に含まれる磁性体粒子の粒径を制御することを特徴とする磁性流体の製造方法。 In producing a magnetic fluid by heating an organometallic compound and a surfactant in a solvent,
The solvent is a mixed solvent including a first solvent and a second solvent having a boiling point higher than that of the first solvent,
A method for producing a magnetic fluid, wherein the particle size of magnetic particles contained in the produced magnetic fluid is controlled by adjusting a mixing ratio of the first solvent and the second solvent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003357892A JP2005123454A (en) | 2003-10-17 | 2003-10-17 | Method of manufacturing ferrofluid, and ferrofluid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003357892A JP2005123454A (en) | 2003-10-17 | 2003-10-17 | Method of manufacturing ferrofluid, and ferrofluid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2005123454A true JP2005123454A (en) | 2005-05-12 |
Family
ID=34614654
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003357892A Withdrawn JP2005123454A (en) | 2003-10-17 | 2003-10-17 | Method of manufacturing ferrofluid, and ferrofluid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2005123454A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009041274A1 (en) | 2007-09-27 | 2009-04-02 | M.Technique Co., Ltd. | Process for producing fine magnetic-substance particle, fine magnetic-substance particle obtained by the same, and process for producing magnetic fluid or magnetic-substance product |
-
2003
- 2003-10-17 JP JP2003357892A patent/JP2005123454A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009041274A1 (en) | 2007-09-27 | 2009-04-02 | M.Technique Co., Ltd. | Process for producing fine magnetic-substance particle, fine magnetic-substance particle obtained by the same, and process for producing magnetic fluid or magnetic-substance product |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Tian et al. | In situ synthesis of copper nanoparticles/polystyrene composite | |
| Perro et al. | Production of large quantities of “Janus” nanoparticles using wax-in-water emulsions | |
| Takahara et al. | Asymmetrically modified silica particles: a simple particulate surfactant for stabilization of oil droplets in water | |
| Reddy et al. | Synthesis of silver nanoparticles using surfactin: A biosurfactant as stabilizing agent | |
| JP4748989B2 (en) | Method for the synthesis of metal nanoparticles | |
| KR101981853B1 (en) | Pickering emulsion composition using polyimide particles and preparation method thereof | |
| JP2006507408A (en) | Method for synthesizing metal nanoparticles | |
| JP2009263226A (en) | Method and apparatus for continuously treating surface of carbon nanotube | |
| JP4204849B2 (en) | Production method of fine copper powder | |
| Wang et al. | Particle contact angle at the oil–water interface: Effect of surface silanization | |
| Saeedi Dehaghani et al. | Utilization of synthesized silane-based silica Janus nanoparticles to improve foam stability applicable in oil production: static study | |
| JP2005123454A (en) | Method of manufacturing ferrofluid, and ferrofluid | |
| KR101713749B1 (en) | Nano diamond, method of manufacturing the same, and nano fluid using the same | |
| JP2008000654A (en) | Manufacturing method of nanoparticle with a particle size of 200 nm or less | |
| RU2651035C1 (en) | Thermal grease | |
| WO2007088810A1 (en) | Process for producing fine carbon fiber agglomerate | |
| Hasab et al. | The effect of surfactant hydrocarbon tail length on the crystallite size of Sr-hexaferrite powders synthesized by a sol–gel auto-combustion method | |
| Jesionowski | Preparation of spherical silica in emulsion systems using the co-precipitation technique | |
| Zang et al. | Design of Janus Nanoparticles for Mobility Control in Heterogeneous Reservoirs | |
| JP5336776B2 (en) | Fine copper powder | |
| Erasmus et al. | Some insights in the sonochemical preparation of cobalt nano-particles | |
| JP2008221207A (en) | Manufacturing method of nanoparticle with particle size of 200 nm or less | |
| Choi et al. | Electrochemical synthesis of red fluorescent silicon nanoparticles | |
| JP2005290478A (en) | Method for producing nano-particle of gold | |
| JP4638714B2 (en) | Water-in-oil emulsion composition for forming porous silicone elastomer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20070109 |