KR100243564B1 - Manufacturing method of magnetic fluid - Google Patents
Manufacturing method of magnetic fluid Download PDFInfo
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- KR100243564B1 KR100243564B1 KR1019960062794A KR19960062794A KR100243564B1 KR 100243564 B1 KR100243564 B1 KR 100243564B1 KR 1019960062794 A KR1019960062794 A KR 1019960062794A KR 19960062794 A KR19960062794 A KR 19960062794A KR 100243564 B1 KR100243564 B1 KR 100243564B1
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- coupling agent
- magnetic fluid
- ferromagnetic
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- 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
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- 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
- H01F1/42—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of organic or organo-metallic materials, e.g. graphene
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
Abstract
본 발명은 강자성체 미립자표면의 개질방법에 관한 것으로서, 더욱 자세하게는 강자성체 미립자표면에 계면활성제가 가열탈수축합됨으로써 강자성체가 고비점 유기용매에 안정하게 분산된 자성유체 제조방법에 관한 것이다.The present invention relates to a method for reforming a ferromagnetic particulate surface, and more particularly, to a method of producing a magnetic fluid in which a ferromagnetic substance is stably dispersed in a high boiling organic solvent by thermal dehydration of a surfactant on a ferromagnetic particulate surface.
본 발명에서는 먼저 실란 카플링제가 강자성체 미립자에 결합된다. 그리고나서, 강자성체 미립자에 결합된 실란 카플링제와 계면활성제가 가열축합됨으로써 화학결합을 형성한다. 다음에 계면활성제와 결합된 강자성체 미립자가 고비점 유기용매에 분산됨으로써 고비점 자성유체가 제조된다.In the present invention, the silane coupling agent is first bonded to the ferromagnetic fine particles. Then, the silane coupling agent and the surfactant bonded to the ferromagnetic particles are thermally condensed to form a chemical bond. Next, the ferromagnetic fine particles combined with the surfactant are dispersed in a high boiling organic solvent to produce a high boiling magnetic fluid.
이렇게 하여 만들어진 자성유체는 유체속에 강자성초미립자가 매우 안정하게 분산된 콜로이드용액으로서 상당한 크기의 원심력이나 자장이 유체에 가해지더라도 입자가 유체로 부터 분리되지 않으며, 결과적으로 자성유체는 자장중에서 자성을 갖는 액체로서 거동하게 된다.The magnetic fluid produced in this way is a colloidal solution in which ferromagnetic ultrafine particles are very stably dispersed in the fluid. Even though a considerable amount of centrifugal force or magnetic field is applied to the fluid, the particles are not separated from the fluid. As a result, the magnetic fluid is a magnetic fluid in the magnetic field. It acts as.
Description
[발명의 명칭][Name of invention]
자성유체의 제조방법Method of manufacturing magnetic fluid
[발명의 상세한 설명]Detailed description of the invention
[발명의 목적][Purpose of invention]
[발명이 속하는 기술분야 및 그 분야의 종래기술][Technical field to which the invention belongs and the prior art in that field]
본 발명은 강자성체 미립자표면의 개질방법에 관한 것으로서, 더욱 자세하게는 강자성체 미립자표면에 계면활성제가 가열탈수축합됨으로써 강자성체가 고비점 유기용매에 안정하게 분산된 자성유체 제조방법에 관한 것이다.The present invention relates to a method for reforming a ferromagnetic particulate surface, and more particularly, to a method of producing a magnetic fluid in which a ferromagnetic substance is stably dispersed in a high boiling organic solvent by thermal dehydration of a surfactant on a ferromagnetic particulate surface.
자성유체를 제조하는 방법 중 하나로 계면활성제를 사용하는 방법이 알려져 있는데, 이 방법에서는 강자성체 미립자의 표면은 계면활성제로 피복된다. 그리하면 계면활성제의 친수기는 강자성체 미립자의 표면을 향해 흡착되고, 소수기는 분산매로 배향되어 강자성체 미립자가 안정하게 분산매중에 분산하게 된다. 즉, 다음의 방정식 1과 같이 Fe2+및 Fe3+를 8NH4OH와 반응시켜 Fe3O4를 얻은 다음, 이것에 계면활성제인 올레인산을 흡착시킨 후, 고비점 유기용매인 광유에 분산시켜 자성유체를 제조하는 방법이다.One method of producing a magnetic fluid is known to use a surfactant, in which the surface of the ferromagnetic particles is coated with a surfactant. The hydrophilic group of the surfactant is then adsorbed toward the surface of the ferromagnetic fine particles, the hydrophobic groups are oriented in the dispersion medium, and the ferromagnetic fine particles are stably dispersed in the dispersion medium. That is, Fe 2+ and Fe 3+ are reacted with 8NH 4 OH to obtain Fe 3 O 4 as shown in Equation 1 below, and then oleic acid as a surfactant is adsorbed to it, and then dispersed in mineral oil as a high boiling organic solvent. It is a method for producing a magnetic fluid.
그러나, 이러한 방법에 의해 제조된 자성유체 조성물은, 계면활성제와 강자성체 입자 표면이 흡착이라는 정전기적인 약한 상호작용을 하고 있기 때문에 열의 영향, 극성용매의 혼입 혹은 외부 전압의 인가 등의 외부요인의 영향을 받아 강자성체 미립자에서 계면활성제가 분리, 침강하므로 장기적 안정성을 유지하기 어렵다는 문제점이 있다.However, since the magnetic fluid composition prepared by this method has a weak electrostatic interaction between the surface of the surfactant and the ferromagnetic particles, the adsorption effect of external factors such as the influence of heat, the incorporation of a polar solvent, or the application of an external voltage. Since the surfactant is separated and sedimented from the ferromagnetic particles, it is difficult to maintain long-term stability.
다른 종래기술으로 실란 카플링제를 사용하여 자성유체를 제조하는 방법이 알려져 있다. 이 방법은 습식법으로 제조된 강자성체 미립자 표면에 있는 반응기인 OH기와 실란 카플링제의 실라놀기를 탈수축합반응시킴으로써 강자성미립자와 실란 카플링제를 화학결합시킨다. 그리고 실란 카플링제와 화학결합된 강자성체 미립자와 편말단에 에폭시 기를 갖는 편단말 반응성 실리콘 오일 및 분산매인 저비점 디메틸폴리실록산을 볼 밀(ball mill)에서 처리함으로써 강자성체 입자표면의 -OH기와 화학결합하고 있는 실란 카플링제의 아미노기에 편말단 반응성 실리콘 오일말단의 에폭시기를 부가반응시킨다. 다음으로 분산성이 나쁜 입자를 제거하고 나서 저비점 디메틸폴리실록산을 증발 제거시키고, 건조된 입자를 고점도 디메틸폴리실록산에 분산시켜 자성유체를 제조하는 방법이다.In another prior art, a method of producing a magnetic fluid using a silane coupling agent is known. This method chemically bonds the ferromagnetic fine particles with the silane coupling agent by dehydrating the OH group and the silanol group of the silane coupling agent on the surface of the ferromagnetic particles produced by the wet method. And a silane chemically bonded to the -OH group on the surface of the ferromagnetic particle by treating a ferromagnetic fine particle chemically bonded with a silane coupling agent and a single-terminal reactive silicone oil having an epoxy group at one end and a low boiling point dimethylpolysiloxane as a dispersion medium in a ball mill. The epoxy group of the single terminal reactive silicone oil terminal is added to the amino group of the coupling agent. Next, the low boiling point dimethylpolysiloxane is removed by evaporating the particles having poor dispersibility, and the dried particles are dispersed in the high viscosity dimethylpolysiloxane to prepare a magnetic fluid.
그러나 실란 카플링제로 처리된 자성분말에 계면활성제를 화학적으로 결합시키기 위해 볼 밀(ball mill)을 사용함에 의해 자성유체를 제조하는데 많은 시간이 소요된다는 문제점이 있다.However, there is a problem in that it takes a long time to prepare a magnetic fluid by using a ball mill to chemically bond the surfactant to the magnetic powder treated with the silane coupling agent.
[발명이 이루고자 하는 기술적 과제][Technical problem to be achieved]
본 발명은 고비점 유기용매에 분산된 강자성체 미립자가 장기적 분산안정성을 갖고 있는 자성유체를 제공하는 것을 목적으로 한다.An object of the present invention is to provide a magnetic fluid in which ferromagnetic particles dispersed in a high boiling organic solvent have long-term dispersion stability.
본 발명의 다른 목적은 제조비용이 저렴하고, 제조시간이 단축된 자성유체 제조방법을 제공하는 것이다.Another object of the present invention is to provide a method for manufacturing a magnetic fluid having low manufacturing cost and shortening manufacturing time.
[발명의 구성 및 작용][Configuration and Function of Invention]
본 발명에 따르면 실란 카플링제를 이용하여 계면활성제가 강자성체 미립자 표면에 가열탈수축합됨으로써 상기 강자성체 미립자가 고비점 유기 용매에 안정하게 분산된 자성유체 제조방법이 제공된다.According to the present invention, a method of producing a magnetic fluid in which a surfactant is thermally dehydrated and condensed on a surface of a ferromagnetic particle using a silane coupling agent is stably dispersed in a high boiling point organic solvent.
본 발명은 습식법으로 제조된 강자성체 미립자와, 상기 강자성체 미립자표면에 직접 화학결합하는 반응기를 갖춘 카플링제와, 그리고 이 카플링제의 다른 반응기와 직접 화학결합할 수 있는 반응기를 갖춘 계면활성제를 반응시킨 강자성체 미립자를 고비점 유기용매에 분산시키는 자성유체 제조방법으로서, 실란 카플링제가 강자성체 미립자에 결합되는 단계와, 상기 강자성체 미립자와 결합된 실란 카플링제의 다른 반응기와 계면활성제가 저비점 유기용매 존재하에서 가열되면서 탈수축합되는 단계와, 계면활성제가 결합된 상기 강자성체 미립자를 고비점 유기용매에 분산시키는 단계를 포함하는 자성유체 제조방법이다.The present invention relates to a ferromagnetic material reacted with a ferromagnetic fine particle produced by a wet method, a coupling agent having a reactor that chemically bonds directly to the ferromagnetic particle surface, and a surfactant having a reactor capable of directly chemically bonding the other coupling agent of the coupling agent. A method of producing a magnetic fluid in which fine particles are dispersed in a high boiling organic solvent, wherein the silane coupling agent is bonded to the ferromagnetic fine particles, and other reactors and surfactants of the silane coupling agent combined with the ferromagnetic fine particles are dehydrated while being heated in the presence of a low boiling organic solvent. And a step of condensing and dispersing the ferromagnetic fine particles combined with a surfactant in a high boiling point organic solvent.
본 발명에 대하여 상세히 설명하면 다음과 같다.The present invention will be described in detail as follows.
본 발명에서 사용되는 실란 카플링제는 XSi(OR)3의 구조를 가지며, X는 각종 합성수지 등의 유기재료와 화학결합하는 반응기로서 비닐기, 에폭시기, 아미노기, 메타크릴기, 메르카푸토기 등이 적용될 수 있으며, OR은 유리금속 등의 무기재료와 화학적으로 결합하는 반응기로서 메톡시기, 에톡시기 등이 적용될 수 있다. 상기와 같은 구조를 갖는 실란 카플링제의 반응기구를 살펴보면, 먼저 실란 카플링제의 알콕시시릴기(Si-OR)는 물 또는 습기에 의해 가수분해되어 실라놀기(Si-OH)가 된다. 한편, 습식법으로 제조된 강자성 미립자는 표면에 -OH기를 가지고 있다. 가수분해에 의해 형성된 실란 카플링제의 실라놀기와 강자성 미립자 표면의 OH기간에 탈수축합반응이 일어나서 Si-O-M결합을 형성한다. 그리하여, 실란 카플링제는 강자성 미립자의 표면에 화학적으로 단단히 고정된다. 한편, 강자성체 미립자와 결합하고 있는 실란 카플링제의 다른 반응기(X)는 각종 합성수지 등의 유기재료와 화학결합할 수 있는 반응기이다. 이와 같이, 실란 카플링제의 한 반응기(OR)는 유기물인 계면활성제와 결합되고, 다른 반응기(X)는 무기물인 강자성체 미립자와 결합된다. 즉, 실란 카플링제는 강자성체미립자와 계면활성제가 화학적으로 결합하도록 중간역할을 한다.The silane coupling agent used in the present invention has a structure of XSi (OR) 3 , X is a reactor that chemically bonds with organic materials such as various synthetic resins, vinyl group, epoxy group, amino group, methacryl group, mercapto group, etc. OR may be a methoxy group, ethoxy group, etc. may be applied as a reactor chemically bonded to inorganic materials such as glass metal. Looking at the reactor of the silane coupling agent having the above structure, first, the alkoxysilyl group (Si-OR) of the silane coupling agent is hydrolyzed by water or moisture to become a silanol group (Si-OH). On the other hand, the ferromagnetic fine particles produced by the wet method have a -OH group on the surface. Dehydration and condensation reaction occurs in the OH period of the silanol group of the silane coupling agent formed by hydrolysis and the surface of the ferromagnetic fine particles to form a Si-OM bond. Thus, the silane coupling agent is chemically firmly fixed to the surface of the ferromagnetic fine particles. On the other hand, another reactor (X) of the silane coupling agent bonded to the ferromagnetic particles is a reactor capable of chemically bonding organic materials such as various synthetic resins. As such, one reactor (OR) of the silane coupling agent is combined with a surfactant, which is an organic material, and the other reactor (X), is combined with ferromagnetic particles, which are inorganic materials. That is, the silane coupling agent plays an intermediate role in chemically bonding the ferromagnetic particulates and the surfactant.
그리고, 본 발명에서는 자성유체를 제조하기 위해 계면활성제를 자성체 분말에 가열탈수축합하는 방법을 이용하였다. 우선, 습식법으로 제조된 강자성초미립자 표면의 수산기(-OH)와 실란 카플링제의 실라놀기가 탈수축합반응하여 Si-O-M 결합을 형성한다. 그리하여 강자성체 미립자와 결합된 실란 카플링제의 다른 반응기(X)와 반응기로 카르복실기(-COOH)를 갖는 계면활성제가 크실렌 존재하에서 160℃ 정도로 가열되면, 강자성체 미립자의 바깥쪽으로 배향하는 실란 카플링제의 반응기(X)와 계면활성제의 반응기인 카르복실기가 탈수축합되어 화학결합을 형성한다. 여기서, 카르복실기를 반응기로 갖는 계면활성제로는 올레인산(C17H33COOH), 스테아린산(C17H35COOH)등이 사용된다. 이와 같은 방법으로 하기의 반응식 2로 표시되는 반응이 형성되어 유기물인 계면활성제가 강자성체 미립자 표면에 안정하게 결합되었다. 그리고, 상기 가열축합된 반응물에 자석을 놓고 정치한 후에 데칸테이션(decantation)을 행하면 비분산 고형물이 제거된다. 이렇게 제조된 크실렌 베이스 자성유체가 고비점 유기용매에 첨가된 후 가열됨으로써 저비점 유기용매인 크실렌이 증발된다. 이렇게 무기물과 유기물이 화학적으로 결합된 강자성 미립자가 고비점 유기용매에 분산됨으로써 본 발명의 목적에 적합한 자성유체가 제조된다.In the present invention, a method of heating and dehydrating a surfactant to a magnetic powder was used to prepare a magnetic fluid. First, the hydroxyl group (-OH) on the surface of the ferromagnetic ultrafine particles produced by the wet method and the silanol group of the silane coupling agent are dehydrogenated to form Si-OM bonds. Thus, when another surfactant (X) of the silane coupling agent combined with the ferromagnetic particles and the surfactant having a carboxyl group (-COOH) are heated to about 160 ° C. in the presence of xylene, the reactor of the silane coupling agent that is oriented outward of the ferromagnetic particles ( A carboxyl group, which is a reactor of X) and a surfactant, is dehydrated to form a chemical bond. Here, as the surfactant having a carboxyl group as a reactor, oleic acid (C 17 H 33 COOH), stearic acid (C 17 H 35 COOH) and the like are used. In this manner, a reaction represented by the following Scheme 2 was formed, and the organic surfactant was stably bonded to the surface of the ferromagnetic particles. Then, decantation is performed after placing the magnet on the heat-condensed reactant to remove non-dispersed solids. The xylene base magnetic fluid thus prepared is added to the high boiling organic solvent and then heated to evaporate xylene, which is a low boiling organic solvent. Thus, the magnetic fluid suitable for the purpose of the present invention is prepared by dispersing ferromagnetic fine particles in which inorganic and organic chemically bonded to a high boiling point organic solvent.
여기서, M은 강자성 미립자이고, 상기 반응식 2에서 R'-NH2가 반응기 X에 해당하며, R'은 탄화수소쇄이며, 탄소수 1이상의 특히 1~3의 직쇄 혹은 분기의 지방족 탄화수소이다.Here, M is a ferromagnetic fine particles, and in the reaction scheme 2 is R'-NH 2 in the reactor X, R 'is a hydrocarbon chain, straight chain or branched aliphatic hydrocarbon group having a carbon number of 1 or more, especially one to three.
본 발명의 실란 카플링제로는 반응기(X)로 아미노기를 가지고 있는 N-β(Amino ethyl) γ-Amino propyl methyl dimethoxy silane, N-β(Amino ethyl) γ-Amino propyl trimethoxy silane, N-β(Amino ethyl) γ-Amino propyl triethoxy silane, γ-Amino propyl trimethoxy silane, γ-Amino propyl triethoxy silane 등의 가운데 선택된 하나 또는 둘이상을 함께 사용할 수 있다.As the silane coupling agent of the present invention, N-β (Amino ethyl) γ-Amino propyl methyl dimethoxy silane having an amino group in the reactor (X), N-β (Amino ethyl) γ-Amino propyl trimethoxy silane, N-β (Amino ethyl) One or more selected from among γ-Amino propyl triethoxy silane, γ-Amino propyl trimethoxy silane, and γ-Amino propyl triethoxy silane can be used together.
본 발명의 카플링제의 첨가량은 강자성체미립자 표면을 단분자막으로 완전히 피복하는 양이 최적이며, 다음의 수학식 1에 의하여 산출할 수 있다.The addition amount of the coupling agent of the present invention is optimally the amount that completely covers the surface of the ferromagnetic particulate with a monomolecular film, and can be calculated by the following equation (1).
여기서, 실란 카플링제의 최소 단면적의 범위는 1분자당 면적으로 13Å이다. 따라서 1g당 면적은 「13Å×Avogadr수(6.02×1023)/분자량」으로 결정된다.Here, the minimum cross-sectional area of the silane coupling agent is 13 kPa in area per molecule. Thus 1g per area is determined as "× 13Å Avogadr number (6.02 × 10 23) / molecular weight".
자성체 입자로서는 강자성체 입자가 좋고, 구체적으로는 마그네타이트, Mn-Zn 페라이트, 코발트 페라이트, 바륨 페라이트 등의 산화물 자성체 입자, 철, 코발트 등의 금속 자성체 입자, 그리고 질화철 입자 중에서 선택된 하나 또는 둘이상의 혼합물을 사용하는 것이 좋다. 특히, 실란 카플링제와 반응성을 고려하면, 표면에 수산기가 많은 산화물 자성체 입자가 좋으며, 제조가 용이한 점을 고려하면 마그네타이트 입자가 좋다.As the magnetic particles, ferromagnetic particles are preferable. Specifically, one or more mixtures selected from oxide magnetic particles such as magnetite, Mn-Zn ferrite, cobalt ferrite and barium ferrite, magnetic metal particles such as iron and cobalt, and iron nitride particles are used. It is good to use. In particular, in consideration of the reactivity with the silane coupling agent, the oxide magnetic particles having a large number of hydroxyl groups on the surface is preferred, the magnetite particles are preferred considering the ease of manufacture.
자성체 입자의 입경으로서는 3nm에서 500nm가 좋고, 바람직하게는 10nm에서 100nm가 좋다. 자성체 입자의 입경이 500nm를 넘으면 분산성이 나빠져서 입자가 침전하게 되며, 3nm이하로 되면 입자가 자성을 나타내지 않게 된다.The particle diameter of the magnetic particles is preferably 3 nm to 500 nm, preferably 10 nm to 100 nm. When the particle diameter of the magnetic particles exceeds 500 nm, the dispersibility becomes poor, and the particles precipitate. When the particle size falls below 3 nm, the particles do not exhibit magnetic properties.
고비점 유기용매로서는 비점이 상압에서 150~700℃, 바람직하게는 200~600℃의 것이 좋고, 더욱 바람직하게는 특히 300~600℃의 것이 좋다. 예컨대 케로신, 경유증분, 윤활유증분 등의 광유계 용매, 노르말 파라핀, 이소파라핀, 알킬벤젠, 알킬나프탈렌, 폴리알파올레핀 등의 합성 탄화수소계, 폴리알킬렌옥사이드, 폴리글리콜, 폴리페닐에테르 등의 에테르계, 폴리올에스테르, 디에스테르, 모노에스테르 등의 에스테르계, 불소화탄화수소계, 그리고 실리콘계 등의 용매가 사용 가능하다.As a high boiling point organic solvent, boiling point is 150-700 degreeC at normal pressure, Preferably it is 200-600 degreeC, More preferably, it is 300-600 degreeC. For example, mineral oil solvents such as kerosene, light oil increments and lubricating oil increments, synthetic hydrocarbons such as normal paraffins, isoparaffins, alkylbenzenes, alkylnaphthalenes and polyalphaolefins, ethers such as polyalkylene oxides, polyglycols and polyphenylethers. Ester solvents, such as esters, polyol esters, diesters, and monoesters, fluorinated hydrocarbons, and silicones, can be used.
이하, 본 발명의 실시예들을 상술한다.Hereinafter, embodiments of the present invention will be described in detail.
[실시예 1]Example 1
Fe2+의 초기농도가 0.9mole/ℓ이고, Fe2+/Fe3+비를 5/6으로 하는 시약급의 FeSO4·7H2O, FeCl3·6H2O을 각각 150㎖ 제조한 후, 1ℓ비이커에 혼합하였다. 기계적 교반기(Mechanical stirrer)로 철염용액을 격심하게 교반하면서 중화제인 NH4OH를 가하여 반응전후의 pH를 9~9.5로 일정하게 해서 마그네타이트가 현탁액을 얻었다. 얻어진 마그네타이트 현탁액의 염분을 제거하기 위해 마그네타이트가 침전된 후 상징액을 제거하고 다시 이온교환수를 가해 정치시킨 후 상징액을 제거했다. 이렇게 함에 의해 슬러리중의 전해질을 제거했다. 이상은 습식법에 의해 마그네타이트 콜로이드를 제조하는 공정이다.150 ml of FeSO 4 · 7H 2 O and FeCl 3 · 6H 2 O of the reagent grade having an initial concentration of Fe 2+ of 0.9 mole / L and a Fe 2+ / Fe 3+ ratio of 5/6 were prepared, respectively. And mixed in a 1 L beaker. While stirring the iron salt solution vigorously with a mechanical stirrer, NH 4 OH, a neutralizing agent was added, and the pH before and after the reaction was constant at 9 to 9.5 to obtain a suspension of magnetite. In order to remove the salt of the obtained magnetite suspension, after the magnetite was precipitated, the supernatant was removed, and again, ion exchanged water was added, and the supernatant was removed. In this way, the electrolyte in the slurry was removed. The above is the process of manufacturing a magnetite colloid by a wet method.
다음에 마그네타이트 약 23.9g을 포함하는 상기 마그네타이트 수(水) 슬러리에 강자성체 미립자의 표면을 완전히 피복할 수 있는 양인 9.47g의 N-β(Amino ethyl) γ-Amino propyl trimethoxy silane을 수용액으로 해서 첨가해 액온을 60℃로 30분간 교반함에 의해, 마그네타이트 미립자의 표면에 실란 카플링제를 흡착시켰다. 이것을 정치시켜 액중의 마그네타이트 입자를 응집 침강시켰다. 그후, 수세 여과하고 진공건조기에서 3시간동안 진공 건조를 행함에 의해 표면이 실란 카플링제로 피복된 분말상의 마그네타이트 미립자를 얻었다.Next, an aqueous solution of 9.47 g of N-β (Amino ethyl) γ-Amino propyl trimethoxy silane, which is an amount capable of completely covering the surface of the ferromagnetic particles, was added to the magnetite water slurry containing about 23.9 g of magnetite as an aqueous solution. The silane coupling agent was made to adsorb | suck the surface of magnetite microparticles | fine-particles by stirring liquid temperature at 60 degreeC for 30 minutes. This was left to stand and the magnetite particles in the liquid were flocculated and precipitated. Thereafter, water filtration and vacuum drying for 3 hours in a vacuum dryer yielded powdery magnetite fine particles whose surface was coated with a silane coupling agent.
1ℓ 비이커에 실란 카플링제로 처리된 건조된 미립자와, 이온교환수 100㎖와 올레인산 12.08g을 넣은 후 초음파를 10분간 가했다. 그 후, 상기 비이커의 내용물을 기계적 교반기로 교반하면서, 액온을 160℃로 2시간동안 유지함에 의해 가열축합반응을 시켰다. 가열축합반응이 완료된 크실렌 베이스 자성유체를 자석에 잠시 정치시킨 후, 데칸테이션(decantation)를 행함에 의해 비분산 고형물이 제거된 크실렌 베이스 자성유체가 얻어졌다. 제조된 크실렌 베이스 자성유체를 스핀들오일(메로파 220, 호남정유)와 마레인화 폴리부텐(HV-100M, 日石化學製品)이 8.8:1.2로 혼합된 오일에 첨가하고 크실렌을 증발함에 의해 고비점 자성유체를 제조하였다. 제조된 자성유체는 포화자화가 100G, 점도가 1,000~10,000cP이었다.The dried fine particles treated with the silane coupling agent, 100 mL of ion-exchanged water and 12.08 g of oleic acid were added to a 1 L beaker, and ultrasonic waves were applied for 10 minutes. Thereafter, while heating the contents of the beaker with a mechanical stirrer, the heat condensation reaction was carried out by maintaining the liquid temperature at 160 ° C for 2 hours. The xylene base magnetic fluid having completed the heat condensation reaction was temporarily left in the magnet, and then decantation was performed to obtain a xylene base magnetic fluid from which non-dispersed solids were removed. The prepared xylene base magnetic fluid was added to an oil mixed with spindle oil (Meropa 220, Honam essential oil) and marinized polybutene (HV-100M, Nippon Chemical Chemical Co., Ltd.) at 8.8: 1.2, and the high boiling point was obtained by evaporating xylene. Magnetic fluid was prepared. The prepared magnetic fluid had a saturation magnetization of 100 G and a viscosity of 1,000 to 10,000 cP.
[실시예 2]Example 2
실란 카플링제로 γ-Amino propyl trimethoxy silane를 사용하여 실시예 1과 동일한 방법으로 자성유체를 제조하였다.Magnetic fluid was prepared in the same manner as in Example 1 using γ-Amino propyl trimethoxy silane as a silane coupling agent.
이렇게 제조된 자성유체 역시 실시예 1과 동일한 열적 특성을 나타냈다.The magnetic fluid thus prepared also showed the same thermal characteristics as in Example 1.
[실시예 3]Example 3
상기 실시예 1에서 얻어진 실란 카플링제로 처리된 건조 미립자와 크실렌 100㎖, 스테아린산 12.17g을 1ℓ비이커에 넣은 후 초음파를 10분간 가했다. 그후, 상기 비이커의 내용물을 기계적 교반기로 교반하면서, 액온을 160℃로 2시간동안 유지함에 의해 가열축합반응을 시켰다. 가열축합반응이 완료된 크실렌 베이스 자성유체를 자석에 잠시 정치시킨 후 데칸테이션(Decantation)를 행함에 의해 비분산 고형물이 제거된 크실렌 베이스 자성유체가 얻어졌다. 제조된 크실렌 베이스 자성유체를 스핀들오일(메로파 220, 호남정유)와 마레인화 폴리부텐(HV-100M, 日石化學製品)이 8.8:1.2로 혼합된 오일에 첨가하고, 크실렌을 증발함에 의해 고비점자성유체를 제조하였다.The dried fine particles treated with the silane coupling agent obtained in Example 1, 100 ml of xylene, and 12.17 g of stearic acid were placed in a 1 L beaker, and ultrasonic waves were added for 10 minutes. Thereafter, while heating the contents of the beaker with a mechanical stirrer, the heat condensation reaction was carried out by maintaining the liquid temperature at 160 ℃ for 2 hours. The xylene base magnetic fluid after completion of the heat condensation reaction was temporarily left in the magnet and then decantation was obtained to remove the xylene base magnetic fluid from which non-dispersed solids were removed. The prepared xylene base magnetic fluid was added to an oil mixed with spindle oil (Merfa 220, Honam Essential Oil) and maranized polybutene (HV-100M, Nippon Chemical Chemical Co., Ltd.) at 8.8: 1.2, and the high ratio was obtained by evaporating xylene. A viscomagnetic fluid was prepared.
이렇게 제조된 자성유체 역시 실시예 1과 동일한 열적 특성을 나타냈다.The magnetic fluid thus prepared also showed the same thermal characteristics as in Example 1.
[발명의 효과][Effects of the Invention]
본 발명에 의하면, 실란 카플링제를 이용하여 계면활성제가 자성체 분말에 화학적으로 결합되고, 상기 자성체 분말이 고비점 유기용매에 분산됨으로써, 장기적인 분산안정성을 갖는 자성유체가 제조될 수 있다. 따라서, 상기 자성유체는 유체 속의 강자성 초미립자가 매우 안정하게 분산된 콜로이드용액으로서 상당한 크기의 원심력이나 자장이 유체에 가해지더라도 입자가 유체로 부터 분리되지 않으며, 결과적으로 자성유체는 자장중에서 자성을 갖는 액체로서 거동하게 된다.According to the present invention, by using a silane coupling agent, the surfactant is chemically bonded to the magnetic powder, and the magnetic powder is dispersed in a high boiling point organic solvent, thereby producing a magnetic fluid having long-term dispersion stability. Therefore, the magnetic fluid is a colloidal solution in which the ferromagnetic ultra-fine particles in the fluid are very stably dispersed. Even when a considerable centrifugal force or magnetic field is applied to the fluid, the particles are not separated from the fluid. As a result, the magnetic fluid is a liquid having magnetic properties in the magnetic field. It acts as.
또한, 종래 실란 카플링제로 처리된 분말에 계면활성제를 화학적으로 결합시키기 위해 볼 밀(ball mill)을 사용하여 장시간 분쇄처리함으로써 자성유체를 제조하였으나, 본 법에 의하면 계면활성제를 실란 카플링제로 처리된 분말에 계면중축합이라는 방법을 사용하여 결합시키기 때문에 단시간에 자성유체를 제조할 수 있고, 공수가 적게 들어 제조비용도 저렴한 장점이 있다.In addition, in order to chemically bind the surfactant to the powder treated with the silane coupling agent, a magnetic fluid was prepared by using a ball mill for a long time, but magnetic fluid was prepared according to the method. The magnetic fluid can be produced in a short time because it is bonded by using a method called interfacial polycondensation.
더욱이 자성유체제조의 중간 단계로서 크실렌을 사용함에 의해 비분산 고형물을 용이하게 제거할 수 있다는 장점 또한 있다.Furthermore, there is also an advantage in that non-dispersed solids can be easily removed by using xylene as an intermediate step in the preparation of the magnetic fluid.
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| US5013471A (en) * | 1988-06-03 | 1991-05-07 | Matsushita Electric Industrial Co., Ltd. | Magnetic fluid, method for producing it and magnetic seal means using the same |
| EP0439367A2 (en) * | 1990-01-26 | 1991-07-31 | Toda Kogyo Corp. | Magnetic toner particles containing iron as the main component and process for producing the same |
| JPH06267731A (en) * | 1993-03-12 | 1994-09-22 | Daikin Ind Ltd | Surface-modified magnetic particle, manufacture thereof and magnetic fluid containing the same |
-
1996
- 1996-12-07 KR KR1019960062794A patent/KR100243564B1/en not_active IP Right Cessation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5013471A (en) * | 1988-06-03 | 1991-05-07 | Matsushita Electric Industrial Co., Ltd. | Magnetic fluid, method for producing it and magnetic seal means using the same |
| EP0439367A2 (en) * | 1990-01-26 | 1991-07-31 | Toda Kogyo Corp. | Magnetic toner particles containing iron as the main component and process for producing the same |
| JPH06267731A (en) * | 1993-03-12 | 1994-09-22 | Daikin Ind Ltd | Surface-modified magnetic particle, manufacture thereof and magnetic fluid containing the same |
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| Publication number | Publication date |
|---|---|
| KR19980044686A (en) | 1998-09-05 |
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