WO2016013847A1 - Magnetorheological fluid containing magnetic particles surrounded with foamed polymers and having excellent stability, and method for producing same - Google Patents

Magnetorheological fluid containing magnetic particles surrounded with foamed polymers and having excellent stability, and method for producing same Download PDF

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WO2016013847A1
WO2016013847A1 PCT/KR2015/007555 KR2015007555W WO2016013847A1 WO 2016013847 A1 WO2016013847 A1 WO 2016013847A1 KR 2015007555 W KR2015007555 W KR 2015007555W WO 2016013847 A1 WO2016013847 A1 WO 2016013847A1
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oil
magnetic particles
polymer layer
fluid
magnetorheological fluid
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PCT/KR2015/007555
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French (fr)
Korean (ko)
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서용석
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서울대학교 산학협력단
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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
    • H01F1/442—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 metal or alloy, e.g. Fe
    • 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
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02B—BOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
    • H02B1/00—Frameworks, boards, panels, desks, casings; Details of substations or switching arrangements
    • H02B1/54—Anti-seismic devices or installations

Definitions

  • the present patent relates to a magnetorheological fluid containing magnetic particles surrounded by porous foamed polymers on the surface thereof, and more particularly, to (i) polymerizing monomers on the surface of magnetic particles to form a polymer layer; ii) putting the magnetic particles having the polymer layer formed on the surface into a compression reaction vessel, and then foaming the polymer layer on the surface using a supercritical fluid or a subcritical fluid; And (iii) dispersing the magnetic particles surrounded by the foamed polymer layer in an oil fraction of 5 to 50% by weight.
  • the manufacturing method of the magnetorheological fluid comprising the magnetorheological fluid having increased stability prepared by such a method. It is about.
  • Magnetorheological fluid is one of the smart intelligent materials that can reversibly adjust the viscosity in response to changes in the magnetic field.
  • the magnetorheological fluid is composed of ferromagnetic, paramagnetic particles and oil medium having a diameter larger than 0.1 ⁇ m, and when the external magnetic field is applied, the particles are arranged as shown in FIG. 1 by polarization on the inside and the surface of the particles. It forms a fiber structure, which serves to improve viscosity and impede fluid flow.
  • the yield stress at this time increases with the strength of the magnetic field, and the fluid flows when the shear stress applied is greater than the yield stress of the fluid.
  • the response rate of the magnetorheological fluid to the magnetic field is very fast (10 -3 seconds) and is reversible, so it is applied to clutches, engine mounts, vibration control devices, high-rise seismic devices, and robotic systems. .
  • 2,575,360 discloses a torque converter that can be used in clutches and brakes, and the composition of magnetorheological fluids that can be used in this equipment results in 50% of carbonyl iron in light lubricant oil.
  • Disclosed is a fluid dispersed at a volume fraction of.
  • An important factor in the practical application of magnetorheological fluids is that magnetorheological behavior is greatly affected by the precipitation problem caused by gravity. The main cause of this precipitation is the deterioration of the stability of the magnetorheological fluid due to the difference in density between ferromagnetic particles (7.86 g / cm 3 ) and the continuous phase (0.95 g / cm 3 for silicon oil). In order to overcome this, continuous efforts have been made.
  • U.S. Patent No. 5,645,752 attempts to minimize the precipitation of magnetic particles by incorporating a shear thinner in a magnetorheological fluid to induce a thixotropic network for hydrogen bonding, but also does not show a marked increase in stability. It was. Therefore, there is a constant need to develop a magnetorheological fluid with improved stability.
  • a magnetic rheology fluid having excellent stability against precipitation in order to develop a magnetorheological fluid having improved stability, a magnetic rheology fluid having excellent stability against precipitation can be prepared by enclosing the magnetic particle surface with a polymer and foaming the particles to prepare a magnetic particle surrounded by a porous polymer foam.
  • the magnetorheological fluid containing magnetic particles surrounded by porous foamed polymers on the surface of the present invention has a very fast and reversible stability at the same time as the response speed to the magnetic field ( 10-3 seconds).
  • the magnetorheological prepared according to the present invention is in a state in which more than 90% is suspended even after one week and has the advantage that can be widely used in the development of various equipment using the magnetorheological by maintaining the yield stress produced in the early stage Yes.
  • 1 is a micrograph showing changes before and after applying a magnetic field to a magnetorheological body.
  • Figure 2 is a schematic diagram showing the cross-section before and after the foaming of the multi-layered magnetic particles according to an embodiment of the present invention
  • [B] is a transmission showing electron micrograph and porosity showing the surface structure of the foamed particles Photomicrograph.
  • [A] of FIG. 3 is a graph showing the change in shear rate as a response to the shear stress of the magnetorheological prepared according to the embodiment of the present invention
  • [B] is the yield stress obtained from the shear stress A graph plotted as a function of voltage.
  • FIG. 4 is a comparative photograph of a magnetorheological body made of multilayered foamed magnetic particles prepared in the present invention and a magnetorheological body made of untreated ferromagnetic particles.
  • Method for producing a magnetorheological fluid comprises the steps of (i) polymerizing a monomer on the surface of the magnetic particles to form a polymer layer; (ii) putting the magnetic particles having a polymer layer on the surface in a compression reaction vessel After foaming the polymer layer on the surface by using a supercritical fluid or a subcritical fluid; And (iii) dispersing the magnetic particles surrounded by the foamed polymer layer in a weight fraction of 5 to 50% in oil.
  • the polymer layer may be made of an amorphous or semi-crystalline polymer that can be easily immersed in the supercritical or subcritical fluid, the oil is a lubricant, mineral oil, silicone oil, castor oil, paraffin oil, vacuum oil, cone Oil and hydrocarbon oil, the magnetic particles comprising iron, carbonyl iron, iron alloy, iron oxide, iron nitride, carbide iron, low carbon steel, nickel, cobalt, mixtures thereof and alloys thereof Can be selected from the group.
  • the oil is a lubricant, mineral oil, silicone oil, castor oil, paraffin oil, vacuum oil, cone Oil and hydrocarbon oil
  • the magnetic particles comprising iron, carbonyl iron, iron alloy, iron oxide, iron nitride, carbide iron, low carbon steel, nickel, cobalt, mixtures thereof and alloys thereof Can be selected from the group.
  • Method for producing a magnetorheological fluid is the surface of the magnetic particles before the step of forming the polymer layer methacrylic acid, polyalcohol, glucose, sorbitol, aminoalcohol, polyethyleneglycol, aminooxide, amine salt, Pretreated with quaternary ammonium salts, pyrimidine salts, sulfonium salts, phosphonium salts, polyethylenepolyamines, carboxylates, sulfonates, sulfates, phosphates, phosphonates, amino acids, betaines, aminosulfates, sulfobetaines and mixtures thereof It may further comprise a step.
  • Magnetorheological fluid according to an aspect of the present invention is prepared by the above method, the magnetic particles surrounded by the foamed polymer layer is dispersed in oil at a weight fraction of 5 to 50% more than 90% even after one week It is in a floating state and has the advantage that it can be widely used in the development of various equipment using magnetorheology by maintaining the yield stress produced in the early stage.
  • Method for producing a magnetorheological fluid of the present invention comprises the steps of (i) polymerizing a monomer on the surface of the magnetic particles to form a polymer layer; (ii) putting the magnetic particles having the polymer layer formed on the surface into a compression reaction vessel, and then foaming the polymer layer on the surface by using a supercritical fluid or a subcritical fluid; And (iii) dispersing the magnetic particles surrounded by the foamed polymer layer in a weight fraction of 5 to 50% in oil.
  • the manufacturing method of the magnetorheological fluid of the present invention will be described in more detail in each step.
  • the first step is to prepare carbonyl iron particles coated with polymer. Pre-treat the iron particles with an emulsifier, etc., add them to a solution containing polymerizable monomer, and then add an initiator and stabilizer to the surface of the iron particles. As the monomer is polymerized, magnetic particles having a polymer layer formed on the surface thereof are formed. That is, after the iron particles are pretreated with an emulsifier or the like and added to a solution containing a polymer monomer, an initiator and a stabilizer are added thereto to prepare magnetic particles having a polymer layer formed by polymerizing the monomer on the iron particles surface. .
  • the magnetic particles having the polymer layer formed on the surface prepared in the first step are put in a high-temperature pressurization reactor, and a supercritical or subcritical fluid is injected thereto, and when the fluid is immersed in the polymer layer after a predetermined time, the reactor outlet is opened.
  • the pressure decreases rapidly, the fluid absorbed in the polymer layer expands to form a foam, and the polymer surrounding the iron particles is changed into a porous polymer.
  • a magnetic particle having a polymer layer formed on the surface thereof is put in a high temperature pressurization reactor, and a supercritical or subcritical fluid is injected therein, and when the fluid is immersed in the polymer layer after a predetermined time, the reactor outlet is opened and a rapid pressure decrease occurs.
  • the absorbed fluid expands to form a foam, and the polymer surrounding the iron particles is changed into a porous polymer.
  • the high pressure fluids used in the present invention are gases used during foaming, and the state is supercritical or lower. Any critical state can be used.
  • Supercritical fluids have very high solubility and dispersibility and are different from normal fluids.
  • pressurized fluid is added thereto using a conventional pressure vessel (autoclave).
  • autoclave a conventional pressure vessel
  • CO 2 carbon dioxide
  • the iron particles surrounded by the prepared porous polymer are dispersed in a fluid medium such as silicon oil, mineral oil, lubricating oil, and the like to make a magnetic rheology.
  • the first step is to prepare carbonyl iron particles coated with a polymer, and the iron particles are pretreated with an emulsifier, etc., and then added to a solution containing a polymer monomer. And a stabilizer or the like to prepare magnetic particles having a polymer layer formed by polymerizing monomers on the surface of iron particles.
  • Polystyrene was polymerized on iron particles of BASF (average particle size 4.25 micrometers, density 7.91 g / cm 3 ) to prepare magnetic particles having a polymer layer.
  • the iron particles are dispersed ultrasonically in a solution containing 10 g of methacrylic acid in 100 grams of methanol, and the mixed solution is washed with methanol to remove excess methacrylic acid. .
  • the methacrylic acid used as the conjugation reaction solution has a carboxyl group attached to the iron particle surface and the acryl part reacts with the styrene monomer radical to produce a polystyrene polymer on the iron surface.
  • Example 1 The particles prepared in Example 1 are placed in a reactor and are subjected to high temperature and high pressure (83 atmospheres of 60 degrees supercritical state (critical temperature of 27 degrees or more and critical pressure of 72.9 atmospheres or more), but in reality, even lower pressures of subcritical state can be foamed. Inject CO 2 fluid. When the outlet is opened after a certain time, a sudden pressure decrease occurs, and the fluid absorbed in the particles expands to form a foam, thereby transforming the polymer surrounding the iron particles into a porous polymer, thereby rapidly decreasing the density.
  • high temperature and high pressure 83 atmospheres of 60 degrees supercritical state (critical temperature of 27 degrees or more and critical pressure of 72.9 atmospheres or more)
  • Inject CO 2 fluid When the outlet is opened after a certain time, a sudden pressure decrease occurs, and the fluid absorbed in the particles expands to form a foam, thereby transforming the polymer surrounding the iron particles into a porous polymer, thereby rapidly decreasing the density.
  • FIG. 2 [A] is a schematic diagram showing the cross-section before and after the foaming of the multi-layered magnetic particles according to an embodiment of the present invention
  • [B] is a transmission showing electron micrograph and porosity showing the surface structure of the foamed particles Micrograph
  • Magneto-Ruclear Manufacturing Process The magnet particles surrounded by the prepared porous polymer are dispersed in a fluid medium (silicone oil, mineral oil, lubricating oil, etc.) to make a magnetorheological body.
  • a fluid medium silicone oil, mineral oil, lubricating oil, etc.
  • Shear Stress Change of Magnetic Rheological Fluid According to Magnetic Field The shear stress of the magnetorheological fluid prepared in Example 3 was measured using a rheometer (Physica MC 300, Stuttgart, Germany) equipped with a rheometer (magnetic field generator). It was.
  • FIG. 3 is a graph showing a change in the shear stress of the magnetorheological fluid under each magnetic field region. The intensity of the magnetic field was changed by changing the current. As shown in FIG. 3, when the magnetic field is 0, the Newtonian fluid behavior is shown, and when the magnetic field is applied, the Bingham fluid behavior is shown. As the magnitude of the magnetic field increases with increasing voltage, the shear stress increases.
  • Sedimentation rate change of the magnetorheological fluid in which the magnetic particles are dispersed The magnetic rheology of the magnetic particles prepared in Example 3 was dispersed in a vial and the sedimentation of the multilayer structure particles was observed. 4A is an initial magnetorheological fluid, and FIG. 4B is a state after one week. In the case of the multilayer structure, 90% of the total particles are still suspended after one week, whereas in the case of pure carbonyl iron, most of them are precipitated and become a clean solution.
  • the magnetorheological fluid prepared in the present invention is composed of ferromagnetic, paramagnetic particles and oil medium having a diameter larger than 0.1 ⁇ m, and when the external magnetic field is applied, the particles are arranged in the inside and the surface of the particles by polarization and the fibers Yield stress is generated by forming a fibril structure and hindering the flow of fluid and improving viscosity. At this time, the yield stress increases with the strength of the magnetic field, and when the shear stress applied is greater than the yield stress of the fluid Fluid will flow.
  • the polymer surrounding the ferromagnetic particles undergoes a foaming process to have porosity, thereby reducing density and increasing stability, thereby significantly reducing the settling speed of the multilayer structure particles.
  • the response speed to the magnetic field of this magnetic fluid is very fast, reversible and stability is improved at the level of milliseconds (10 -3 seconds). Therefore, clutch, engine mount, vibration control device, high-rise building seismic device, and robot It can be widely used in the development of various equipments such as a robotic system.

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  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Soft Magnetic Materials (AREA)
  • Lubricants (AREA)

Abstract

A magnetorheological fluid, according to the present invention, has multilayer-structured particles formed therein by having ferromagnetic particles surrounded with polymers, and the multilayer-structured particles gain porosity by going through a foaming process, thereby decreasing the density and increasing the stability of the magnetorheological fluid, thereby enabling the marked decrease in the settling velocity thereof. The magnetorheological fluid has a millisecond (10-3 second) level response speed to a magnetic field, thereby being very fast, reversible, and simultaneously, having enhanced stability, and thus may be widely used for the development of various equipment using magnetorheological fluid.

Description

안정성이 우수한 발포고분자로 둘러싸인 자성입자를 함유하는 자기유변체 및 그 제조방법Magnetic rheology containing magnetic particles surrounded by foamed polymer with excellent stability and manufacturing method thereof
본 특허는 표면에 다공성의 발포고분자로 둘러싸인 자성입자를 함유하는 자기유변유체 및 그 제조방법에 대한 것으로 보다 상세하게는 (i) 자성입자의 표면에서 단량체를 중합하여 고분자층을 형성시키는 단계;(ii) 표면에 고분자층이 형성된 자성입자를 압축반응용기에 넣은 후 초임계유체 또는 아임계유체를 이용하여 표면의 고분자층을 발포 시키는 단계; 및 (iii) 발포된 고분자층으로 둘러싸인 자성입자를 오일에 5 내지 50%의 무게분율로 분산시키는 단계;를 포함하는 자기유변유체의 제조방법과 이러한 방법에 의하여 제조되는 안정성이 증가된 자기유변체에 관한 것이다.The present patent relates to a magnetorheological fluid containing magnetic particles surrounded by porous foamed polymers on the surface thereof, and more particularly, to (i) polymerizing monomers on the surface of magnetic particles to form a polymer layer; ii) putting the magnetic particles having the polymer layer formed on the surface into a compression reaction vessel, and then foaming the polymer layer on the surface using a supercritical fluid or a subcritical fluid; And (iii) dispersing the magnetic particles surrounded by the foamed polymer layer in an oil fraction of 5 to 50% by weight. The manufacturing method of the magnetorheological fluid comprising the magnetorheological fluid having increased stability prepared by such a method. It is about.
본 출원은 2014년 7월 21일에 출원된 한국특허출원 제10-2014-0091887호에 기초한 우선권을 주장하며, 해당 출원의 명세서 및 도면에 개시된 모든 내용은 본 출원에 원용된다.This application claims the priority based on Korean Patent Application No. 10-2014-0091887 filed on July 21, 2014, all the contents disclosed in the specification and drawings of the application are incorporated in this application.
자기유변유체는 자기장의 변화에 대응하여 가역적으로 점도의 조절이 가능한스마트지능재료(smart intelligent material)의 하나이다. 자기유변유체는 지름이 0.1㎛ 보다 큰 강자성, 상자성 입자와 오일미디움으로 이루어져 있으며, 외부의 자기장이 가해지면 입자의 내부와 표면에 분극현상(polarization)에 의해서 도 1과 같이 입자들이 배열하고 섬유구조(fibril structure)를 형성하는데, 이 섬유구조가 점도 향상과 유체의 흐름을 방해하는 역할을 한다. 이때의 항복응력(yield stress)은 자기장의 세기에 따라 증가하고, 가해진 전단응력(shear stress)이 유체의 항복응력보다 커지면 유체가 흐르게 된다. 자기장에 대한 자기유변유체의 응답속도는 미리초(10-3 초) 수준으로 매우 빠르며, 가역적이어서, 클러치, 엔진마운트, 진동제어장치, 고층건물 내진 장치, 로보틱 시스템(robotic system) 등에 응용된다.Magnetorheological fluid is one of the smart intelligent materials that can reversibly adjust the viscosity in response to changes in the magnetic field. The magnetorheological fluid is composed of ferromagnetic, paramagnetic particles and oil medium having a diameter larger than 0.1 μm, and when the external magnetic field is applied, the particles are arranged as shown in FIG. 1 by polarization on the inside and the surface of the particles. It forms a fiber structure, which serves to improve viscosity and impede fluid flow. The yield stress at this time increases with the strength of the magnetic field, and the fluid flows when the shear stress applied is greater than the yield stress of the fluid. The response rate of the magnetorheological fluid to the magnetic field is very fast (10 -3 seconds) and is reversible, so it is applied to clutches, engine mounts, vibration control devices, high-rise seismic devices, and robotic systems. .
대한민국 공개특허 제2002-0064654호에서 밝힌 바와 같이 승용차, 트럭 등의 댐퍼(damper), 브레이크(brake)에 사용되는 효울적인 자기유변유체를 제조하기 위하여는, 무엇보다도 높은 항복응력(yield stress)을 가지는 자기유변유체의 제조가 필수적이며, 이를 위하여 자성입자의 부피분율을 높이거나 또는 강한 자기장을 부과하는 방법이 사용될 수 있으나, 자성입자의 부피분율을 높일 경우, 장비의 하중 및 구동전력 소모를 증가시키고, 강한 자기장을 부과할 경우, 자기장 무부하시의 점도를 증가시키는 단점을 안고 있기 때문에 바람직하지 않다. 이에, 상기한 단점을 해결한 자기유변유체를 개발하여, 이를 효과적으로 적용하기 위한 노력이 계속되고 있다. 미국특허 제2,575,360호에서는 클러치와 브레이크에서 사용될 수 있는 토크 변환장치를 개시하고 있고, 이 장비에 사용될 수 있는 자기유변유체의 조성으로 자성입자(carbonyl iron)가 광윤활유(light lubricant oil)에 50%의 부피분율로 분산되어있는 유체를 개시하고 있다. 자기유변유체의 실제 응용시에 중요한 인자는 중력에 의한 침전문제로 인하여, 자기유변학적 거동이 큰 영향을 받는다는 점이다. 이 침전의 주요한 원인은 철자성입자(7.86g/cm3)와 연속상(silicon oil의 경우 0.95g/cm3)사이의 밀도의 차이에서 기인한 자기유변유체의 안정성 저하이다. 이를 극복하기 위하여 지속적인 노력이 계속되고 있는데, 미국특허 제5,043,070호에서는 2가지층의 계면활성제를 자성입자에 코팅한 자성입자를 사용하여 자기유변유체의 안정화를 시도하였으나 효과는 만족스러운 수준에 이르지 못하였고, 미국특허 제 5,645,752호에서는 자기유변유체에 전단엷음첨가제를 혼합하여, 수소결합을 위한 틱소트로픽 가교(network)를 유도함으로써 자성입자의 침전을 최소화 하려고 시도하였으나, 역시 뚜렷한 안정성의 증가를 나타내지 못하였다. 따라서, 안정성이 향상된 자기유변유체를 개발하여야 할 필요성이 끊임없이 대두되었다.As described in Korean Patent Laid-Open Publication No. 2002-0064654, in order to manufacture an effective magnetorheological fluid used for dampers and brakes of passenger cars, trucks, etc., high yield stress is required. It is essential to manufacture a magnetorheological fluid. For this purpose, a method of increasing the volume fraction of the magnetic particles or imposing a strong magnetic field may be used. However, increasing the volume fraction of the magnetic particles increases the load and driving power consumption of the equipment. In this case, when a strong magnetic field is imposed, it is not preferable because it has a disadvantage of increasing the viscosity under no load of the magnetic field. Thus, by developing a magnetorheological fluid that solves the above disadvantages, efforts have been made to apply it effectively. U.S. Patent No. 2,575,360 discloses a torque converter that can be used in clutches and brakes, and the composition of magnetorheological fluids that can be used in this equipment results in 50% of carbonyl iron in light lubricant oil. Disclosed is a fluid dispersed at a volume fraction of. An important factor in the practical application of magnetorheological fluids is that magnetorheological behavior is greatly affected by the precipitation problem caused by gravity. The main cause of this precipitation is the deterioration of the stability of the magnetorheological fluid due to the difference in density between ferromagnetic particles (7.86 g / cm 3 ) and the continuous phase (0.95 g / cm 3 for silicon oil). In order to overcome this, continuous efforts have been made. US Patent No. 5,043,070 attempts to stabilize the magnetorheological fluid using magnetic particles coated with two layers of surfactants on magnetic particles, but the effect is not satisfactory. U.S. Patent No. 5,645,752 attempts to minimize the precipitation of magnetic particles by incorporating a shear thinner in a magnetorheological fluid to induce a thixotropic network for hydrogen bonding, but also does not show a marked increase in stability. It was. Therefore, there is a constant need to develop a magnetorheological fluid with improved stability.
본 발명에서는 안정성이 향상된 자기유변유체를 개발하고자 자성입체표면을 고분자로 둘러싸고 이 입자를 발포시켜 다공성 고분자 발포체로 둘러싸인 자성입체를 제조함으로써 침전에 대한 안정성이 우수한 자기유변유체를 제조할 수 있다.In the present invention, in order to develop a magnetorheological fluid having improved stability, a magnetic rheology fluid having excellent stability against precipitation can be prepared by enclosing the magnetic particle surface with a polymer and foaming the particles to prepare a magnetic particle surrounded by a porous polymer foam.
본 발명에 따른 표면에 다공성의 발포고분자로 둘러싸인 자성입자를 함유하는 자기유변유체는 자기장에 대한 응답속도는 미리초(10-3 초) 수준으로 매우 빠르고 가역적인 동시에 안정성이 향상되었다. 특히, 본 발명에 따라 제조된 자기유변체는 1주일이 지나도 90% 이상이 부유된 상태로 있으며 초기 제조된 항복응력을 그대로 유지함으로써 자기유변체를 이용한 각종 장비의 개발에 널리 활용할 수 있는 장점이 ㅇ있다.The magnetorheological fluid containing magnetic particles surrounded by porous foamed polymers on the surface of the present invention has a very fast and reversible stability at the same time as the response speed to the magnetic field ( 10-3 seconds). In particular, the magnetorheological prepared according to the present invention is in a state in which more than 90% is suspended even after one week and has the advantage that can be widely used in the development of various equipment using the magnetorheological by maintaining the yield stress produced in the early stage Yes.
도 1은 자기유변체에 자기장을 인가하기 전과 후의 변화를 나타낸 현미경 사진이다.1 is a micrograph showing changes before and after applying a magnetic field to a magnetorheological body.
도 2의 [A]는 본 발명에 일 구현예에 따른 다층구조 자성입자의 발포 전과 발포 후의 단면을 나타낸 모식도이고, [B]는 발포된 입자의 표면구조를 나타낸 전자현미경사진 및 다공성을 보여주는 투과현미경 사진이다.Figure 2 [A] is a schematic diagram showing the cross-section before and after the foaming of the multi-layered magnetic particles according to an embodiment of the present invention, [B] is a transmission showing electron micrograph and porosity showing the surface structure of the foamed particles Photomicrograph.
도 3의 [A]는 본 발명의 일 구현예에 따라 제조된 자기유변체의 전단응력에 대한 반응으로서 전단율에 대한 변화를 도시한 그래프이고, [B]는 전단응력으로부터 얻어진 항복응력을 입력전압에 대한 함수로 도시한 그래프이다. [A] of FIG. 3 is a graph showing the change in shear rate as a response to the shear stress of the magnetorheological prepared according to the embodiment of the present invention, [B] is the yield stress obtained from the shear stress A graph plotted as a function of voltage.
도4는 본 발명에서 제조한 다층구조 발포 자성입자로 제조된 자기유변체와 처리하지 않은 철자성입자로 제조된 자기유변체의 비교사진이다.4 is a comparative photograph of a magnetorheological body made of multilayered foamed magnetic particles prepared in the present invention and a magnetorheological body made of untreated ferromagnetic particles.
이하 본 발명의 일 구현 예에 따른 자기유변유체 및 그 제조방법에 대하여 설명한다.Hereinafter, a magnetorheological fluid and a manufacturing method thereof according to an embodiment of the present invention will be described.
본 발명의 일 측면에 따른 자기유변유체의 제조방법은 (i) 자성입자의 표면에서 단량체를 중합하여 고분자층을 형성시키는 단계;(ii) 표면에 고분자층이 형성된 자성입자를 압축반응용기에 넣은 후 초임계유체 또는 아임계유체를 이용하여 표면의 고분자층을 발포 시키는 단계; 및 (iii) 발포된 고분자층으로 둘러싸인 자성입자를 오일에 5 내지 50%의 무게분율로 분산시키는 단계;를 포함한다.Method for producing a magnetorheological fluid according to an aspect of the present invention comprises the steps of (i) polymerizing a monomer on the surface of the magnetic particles to form a polymer layer; (ii) putting the magnetic particles having a polymer layer on the surface in a compression reaction vessel After foaming the polymer layer on the surface by using a supercritical fluid or a subcritical fluid; And (iii) dispersing the magnetic particles surrounded by the foamed polymer layer in a weight fraction of 5 to 50% in oil.
상기 고분자층은 초임계 또는 아임계상태의 유체가 쉽게 침지될 수 있는 비정형 또는 반결정성 고분자로 이루어 질 수 있고, 상기 오일은 윤활유, 미네랄오일, 실리콘오일, 캐스터오일, 파라핀오일, 진공 오일, 콘 오일 및 탄화수소 오일로 구성된 그룹으로부터 선택될 수 있으며, 상기 자성입자는 철, 카보닐철, 철 합금체, 산화철, 질화철, 카바이드철, 저탄소강, 니켈, 코발트, 이들의 혼합물 및 이들의 합금으로 구성된 그룹으로부터 선택될 수 있다. The polymer layer may be made of an amorphous or semi-crystalline polymer that can be easily immersed in the supercritical or subcritical fluid, the oil is a lubricant, mineral oil, silicone oil, castor oil, paraffin oil, vacuum oil, cone Oil and hydrocarbon oil, the magnetic particles comprising iron, carbonyl iron, iron alloy, iron oxide, iron nitride, carbide iron, low carbon steel, nickel, cobalt, mixtures thereof and alloys thereof Can be selected from the group.
본 발명의 일 측면에 따른 자기유변유체의 제조방법은 상기 고분자층을 형성하는 단계 이전에 자성입자의 표면을 메타아크릴산, 폴리알콜, 글루코스, 솔비톨, 아미노알콜, 폴리에틸렌글리콜, 아미노옥사이드, 아민염, 4급암모늄염, 피리미딘염, 설포늄염, 포스포늄염,폴리에틸렌폴리아민, 카복실레이트, 설포네이트, 설페이트, 포스페이트, 포스포네이트, 아미노산, 베타인, 아미노설페이트, 설포베타인 및 이들의 혼합물로 전처리하는 단계를 더 포함할 수 있다.Method for producing a magnetorheological fluid according to an aspect of the present invention is the surface of the magnetic particles before the step of forming the polymer layer methacrylic acid, polyalcohol, glucose, sorbitol, aminoalcohol, polyethyleneglycol, aminooxide, amine salt, Pretreated with quaternary ammonium salts, pyrimidine salts, sulfonium salts, phosphonium salts, polyethylenepolyamines, carboxylates, sulfonates, sulfates, phosphates, phosphonates, amino acids, betaines, aminosulfates, sulfobetaines and mixtures thereof It may further comprise a step.
본 발명의 일 측면에 따른 자기유변유체는 상기의 제조방법에 의하여 제조되어, 발포된 고분자층으로 둘러싸인 자성입자가 오일에 5 내지 50%의 무게분율로 분산되어 있어 1주일이 지나도 90% 이상이 부유된 상태로 있으며 초기 제조된 항복응력을 그대로 유지함으로서 자기유변체를 이용한 각종 장비의 개발에 널리 활용할 수 있는 장점을 가진다.Magnetorheological fluid according to an aspect of the present invention is prepared by the above method, the magnetic particles surrounded by the foamed polymer layer is dispersed in oil at a weight fraction of 5 to 50% more than 90% even after one week It is in a floating state and has the advantage that it can be widely used in the development of various equipment using magnetorheology by maintaining the yield stress produced in the early stage.
본 발명의 자기유변유체의 제조방법은 (i) 자성입자의 표면에서 단량체를 중합하여 고분자층을 형성시키는 단계; (ii) 표면에 고분자층이 형성된 자성입자를 압축반응용기에 넣은 후 초임계유체 또는 아임계유체를 이용하여 표면의 고분자층을 발포 시키는 단계; 및 (iii) 발포된 고분자층으로 둘러싸인 자성입자를 오일에 5 내지 50%의 무게분율로 분산시키는 단계;를 포함한다. 이하, 본 발명의 자기유변유체의 제조방법을 각 단계별로 보다 구체적으로 설명하기로 한다. Method for producing a magnetorheological fluid of the present invention comprises the steps of (i) polymerizing a monomer on the surface of the magnetic particles to form a polymer layer; (ii) putting the magnetic particles having the polymer layer formed on the surface into a compression reaction vessel, and then foaming the polymer layer on the surface by using a supercritical fluid or a subcritical fluid; And (iii) dispersing the magnetic particles surrounded by the foamed polymer layer in a weight fraction of 5 to 50% in oil. Hereinafter, the manufacturing method of the magnetorheological fluid of the present invention will be described in more detail in each step.
제 1 단계는 고분자로 코팅된 카보닐철 입자를 제조하는 공정으로서 철입자를 유화제 등으로 전처리한 후 중합가능한 단량체를 함유하고 있는 용액에 첨가한후 여기에 개시제 및 안정제 등을 투입하여 철입자 표면에 단량체가 중합되면서 표면에 고분자층이 형성된 자성입자를 형성하게 된다. 즉, 철입자를 유화제 등으로 전처리한 후 고분자 단량체를 함유하고 있는 용액에 첨가한 후 여기에 개시제 및 안정제 등을 투입하여 철입자 표면에 단량체가 중합되면서 고분자층이 형성된 자성입자를 제조하는 단계이다.The first step is to prepare carbonyl iron particles coated with polymer. Pre-treat the iron particles with an emulsifier, etc., add them to a solution containing polymerizable monomer, and then add an initiator and stabilizer to the surface of the iron particles. As the monomer is polymerized, magnetic particles having a polymer layer formed on the surface thereof are formed. That is, after the iron particles are pretreated with an emulsifier or the like and added to a solution containing a polymer monomer, an initiator and a stabilizer are added thereto to prepare magnetic particles having a polymer layer formed by polymerizing the monomer on the iron particles surface. .
제 2 단계는 상기 제 1 단계에서 제조된 표면에 고분자층이 형성된 자성입자를 고온가압반응기에 넣고 여기에 초임계 또는 아임계유체를 주입하여 일정시간 후에 고분자층에 유체가 침지되면 반응기 출구를 열어 급격한 압력감소가 일어나면서 고분자층 내에 흡수되어 있던 유체가 팽창하여 발포체를 이루어 철입자를 둘러싸고 있는 고분자가 다공성 고분자로 변하게 된다. 즉, 표면에 고분자층이 형성된 자성입자를 고온가압반응기에 넣고 여기에 초임계 또는 아임계유체를 주입하여 일정시간이 지나서 고분자층에 유체가 침지되면 반응기 출구를 열어 급격한 압력감소가 일어나면서 입자 내에 흡수되어 있던 유체가 팽창하여 발포체를 이루어 철입자를 둘러싸고 있는 고분자가 다공성 고분자로 변하게 된다. 초임계유체의 경우 일정 고온 고압의 한계를 넘어선 상태에 도달하여 액체와 기체가 구분 안되는 상태이나 본 특허에 사용된 상기한 고압유체는 발포시 사용되는 기체로써 그 상태가 초임계상태 또는 그 이하인 아임계 상태든 다 사용할 수 있다. 초임계유체의 경우 용해도 및 분산도가 매우 높고 일반유체와는 다른 특성을 나타낸다. 본 발명에서는 통상적인 압력용기(오토클레이브)를 사용하여 여기에 가압된 유체를 첨가한다. 본 발명의 실시예에서는 환경친화적이고 비교적 다루기 쉬워 널리 사용되는 고온고압의 이산화탄소 CO2를 사용하였으나 이외에도 물, 암모니아 등도 사용될 수 있다. In the second step, the magnetic particles having the polymer layer formed on the surface prepared in the first step are put in a high-temperature pressurization reactor, and a supercritical or subcritical fluid is injected thereto, and when the fluid is immersed in the polymer layer after a predetermined time, the reactor outlet is opened. As the pressure decreases rapidly, the fluid absorbed in the polymer layer expands to form a foam, and the polymer surrounding the iron particles is changed into a porous polymer. That is, a magnetic particle having a polymer layer formed on the surface thereof is put in a high temperature pressurization reactor, and a supercritical or subcritical fluid is injected therein, and when the fluid is immersed in the polymer layer after a predetermined time, the reactor outlet is opened and a rapid pressure decrease occurs. The absorbed fluid expands to form a foam, and the polymer surrounding the iron particles is changed into a porous polymer. In the case of supercritical fluids, liquids and gases cannot be distinguished because they reach a state exceeding a limit of a certain high temperature and high pressure. However, the high pressure fluids used in the present invention are gases used during foaming, and the state is supercritical or lower. Any critical state can be used. Supercritical fluids have very high solubility and dispersibility and are different from normal fluids. In the present invention, pressurized fluid is added thereto using a conventional pressure vessel (autoclave). In the embodiment of the present invention is used environmentally friendly and relatively easy to handle high temperature and high pressure carbon dioxide CO 2 widely used in addition to water, ammonia and the like can also be used.
제 3 단계는 제조된 다공성 고분자로 둘러싸인 철입자를 실리콘오일, 미네랄오일, 윤활유 등의 유체 미디움에 분산시켜서 자기 유변체를 만들게 된다. In the third step, the iron particles surrounded by the prepared porous polymer are dispersed in a fluid medium such as silicon oil, mineral oil, lubricating oil, and the like to make a magnetic rheology.
이하, 실시예를 통하여 본 발명을 보다 구체적으로 설명하고자 한다. 본 실시예는 본 발명을 보다 구체적으로 설명하기 위한 것이며, 본 발명의 범위가 이들 실시예에 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to Examples. This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.
실시예Example 1 One
표면에 고분자층이 형성된 자성입자 제조 단계: 제 1 단계는 고분자로 코팅된 카보닐철 입자를 제조하는 공정으로서 철입자를 유화제 등으로 전처리한 후 고분자 단량체를 함유하고 있는 용액에 첨가한 후 여기에 개시제 및 안정제 등을 투입하여 철입자 표면에 단량체가 중합되면서 고분자층이 형성된 자성입자를 제조하는 단계이다. Preparation of magnetic particles having a polymer layer formed on the surface: The first step is to prepare carbonyl iron particles coated with a polymer, and the iron particles are pretreated with an emulsifier, etc., and then added to a solution containing a polymer monomer. And a stabilizer or the like to prepare magnetic particles having a polymer layer formed by polymerizing monomers on the surface of iron particles.
고분자층이 형성된 자성입자를 제조하기 위하여 BASF의 철입자 (평균입자크기 4.25 마이크론미터, 밀도 7.91 g/cm3)위에 폴리스티렌을 중합하였다. 먼저, 철입자와 고분자(폴리스타이렌)와의 친화성을 부여하기 위하여 철입자를 메탄올 100그램에 메타아크릴산 10g이 섞여 있는 용액에 초음파로 분산시킨 후 혼합용액을 메탄올로 세척하여 과량의 메타아크릴산을 제거한다. 접합반응액으로 사용한 메타아크릴산은 카르복실그룹이 철입자 표면에 반응하며 붙게 되고 아크릴 부분은 스타이렌단량체라디칼과 반응하여 철표면에 폴리스티렌 고분자가 생성되게 한다. 메타아크릴산 처리된 철입자에 18g의 스타이렌 단량체를 첨가한다. 이 혼합물을 6.6g의 폴리비닐피리딘을 안정제로 함유하는 200g의 메탄올 용액에 넣는다. 개시제로 0.54g의 2,2'아조비스(아이소부티로나이트릴)을 반응기에 넣는다. 질소 분위기에서 반응기 온도를 55℃ 에서 24시간 동안 450rpm으로 교반하며 반응시킨다. 반응이 끝나고 난 후 최종 산물을 메탄올 용액에서 자석을 이용하여 분리한 후 60℃에서 24시간 동안 건조시켰다. Polystyrene was polymerized on iron particles of BASF (average particle size 4.25 micrometers, density 7.91 g / cm 3 ) to prepare magnetic particles having a polymer layer. First, in order to give affinity between the iron particles and the polymer (polystyrene), the iron particles are dispersed ultrasonically in a solution containing 10 g of methacrylic acid in 100 grams of methanol, and the mixed solution is washed with methanol to remove excess methacrylic acid. . The methacrylic acid used as the conjugation reaction solution has a carboxyl group attached to the iron particle surface and the acryl part reacts with the styrene monomer radical to produce a polystyrene polymer on the iron surface. 18 g of styrene monomer is added to the methacrylic acid treated iron particles. The mixture is placed in 200 g methanol solution containing 6.6 g polyvinylpyridine as stabilizer. 0.54 g of 2,2 'azobis (isobutyronitrile) is added to the reactor as an initiator. In a nitrogen atmosphere, the reactor temperature is reacted with stirring at 450 rpm for 24 hours at 55 ° C. After the reaction was completed, the final product was separated from the methanol solution using a magnet and dried at 60 ℃ for 24 hours.
실시예Example 2 2
실시예 1에서 제조된 입자를 반응기 내에 넣고 여기에 고온고압 (83기압 60도 초임계 상태 (임계온도 27도 이상 임계압력 72.9기압 이상)에서 행하지만 실제로는 그보다 낮은 압력의 아임계 상태도 발포 가능하다.)의 CO2 유체를 주입한다. 일정시간 후에 배출구를 개방하면 급격한 압력감소가 일어나면서 입자내에 흡수되어 있던 유체가 팽창하여 발포체를 이루어 철입자를 둘러싸고 있는 고분자가 다공성 고분자로 변하게 되고 이로써 밀도가 급격히 낮아지게 된다. The particles prepared in Example 1 are placed in a reactor and are subjected to high temperature and high pressure (83 atmospheres of 60 degrees supercritical state (critical temperature of 27 degrees or more and critical pressure of 72.9 atmospheres or more), but in reality, even lower pressures of subcritical state can be foamed. Inject CO 2 fluid. When the outlet is opened after a certain time, a sudden pressure decrease occurs, and the fluid absorbed in the particles expands to form a foam, thereby transforming the polymer surrounding the iron particles into a porous polymer, thereby rapidly decreasing the density.
도 2의 [A]는 본 발명에 일 구현예에 따른 다층구조 자성입자의 발포 전과 발포 후의 단면을 나타낸 모식도이고, [B]는 발포된 입자의 표면구조를 나타낸 전자현미경사진 및 다공성을 보여주는 투과현미경 사진이다Figure 2 [A] is a schematic diagram showing the cross-section before and after the foaming of the multi-layered magnetic particles according to an embodiment of the present invention, [B] is a transmission showing electron micrograph and porosity showing the surface structure of the foamed particles Micrograph
실시예Example 3 3
자기유변체 제조 공정 : 제조된 다공성고분자로 둘러싸인 철입자를 유체미디움 (실리콘오일, 미네랄오일, 윤활유등)에 분산시켜서 자기 유변체를 만들게 된다. Magneto-Ruclear Manufacturing Process: The magnet particles surrounded by the prepared porous polymer are dispersed in a fluid medium (silicone oil, mineral oil, lubricating oil, etc.) to make a magnetorheological body.
자기유변유체 Magnetorheological fluid 특성 분석 1 Characterization 1
자기장에 따른 자기유변유체의 전단응력 변화 : 실시예 3에서 제조한 자기유변체를 유변물성 측정기(자기장 발생기가 달려있는 회전레오미터 (Physica MC 300, Stuttgart, Germany))를 사용하여 전단응력을 측정하였다. Shear Stress Change of Magnetic Rheological Fluid According to Magnetic Field: The shear stress of the magnetorheological fluid prepared in Example 3 was measured using a rheometer (Physica MC 300, Stuttgart, Germany) equipped with a rheometer (magnetic field generator). It was.
도 3은 각 자기장 영역하에서 자기유변유체의 전단응력 변화를 나타내는 그래프로서 전류를 변화시킴으로써 자기장의 세기가 변화되었다. 도 3에서 보듯이, 자기장이 0일 때에는 뉴토니언유체 거동을 나타내고, 자기장이 가해지면 빙햄유체의 거동을 나타내며, 전압증가에 따른 자기장의 크기가 증가할수록 전단응력이 증가함을 알 수 있었다.3 is a graph showing a change in the shear stress of the magnetorheological fluid under each magnetic field region. The intensity of the magnetic field was changed by changing the current. As shown in FIG. 3, when the magnetic field is 0, the Newtonian fluid behavior is shown, and when the magnetic field is applied, the Bingham fluid behavior is shown. As the magnitude of the magnetic field increases with increasing voltage, the shear stress increases.
자기유변유체 Magnetorheological fluid 특성 분석 2 Characterization 2
자성입자가 분산된 자기유변유체의 침강속도변화 : 실시예 3에서 제조된 자성입자를 분산시킨 자기유변체를 바이얼에 넣고 다층구조입자의 침강을 관찰하였다. 도 4의 [A]는 초기의 자기유변 유체이고 도 4의 [B}는 1주일 후의 상태다. 다층구조체의 경우 1주일 후에도 전체입자의 90%가 그대로 부유되어 있는 것을 볼 수 있는 반면 순수 카보닐아이언의 경우는 대부분이 침전되어 깨끗한 용액이 된 것을 볼 수 있다.Sedimentation rate change of the magnetorheological fluid in which the magnetic particles are dispersed: The magnetic rheology of the magnetic particles prepared in Example 3 was dispersed in a vial and the sedimentation of the multilayer structure particles was observed. 4A is an initial magnetorheological fluid, and FIG. 4B is a state after one week. In the case of the multilayer structure, 90% of the total particles are still suspended after one week, whereas in the case of pure carbonyl iron, most of them are precipitated and become a clean solution.
본 발명에서 제조된 자기유변유체는 지름이 0.1㎛ 보다 큰 강자성, 상자성 입자와 오일미디움으로 이루어져 있으며, 외부의 자기장이 가해지면 입자의 내부와 표면에 분극현상(polarization)에 의해서 입자들이 배열하고 섬유구조(fibril structure)를 형성하여 점도 향상과 유체의 흐름을 방해함으로써 항복응력이 발생하게 되고 이때의 항복응력은 자기장의 세기에 따라 증가하고, 가해진 전단응력(shear stress)이 유체의 항복응력보다 커지면 유체가 흐르게 된다. 본 발명의 자기유변체는 강자성입자를 둘러싸고 있는 고분자가 발포공정을 거침으로써 다공성을 갖게되어 밀도를 줄일 수 있고 안정성이 증가되어 다층구조입자의 침강속도를 현저히 줄일 수 있다. 이 자기유변체의 자기장에 대한 응답속도는 미리초(10-3 초) 수준으로 매우 빠르고 가역적인 동시에 안정성이 향상되었으므로 자기유변유체를 이용한 클러치, 엔진마운트, 진동제어장치, 고층건물 내진 장치, 로보틱 시스템(robotic system) 등의 각종 장비개발에 널리 활용될 수 있을 것이다.The magnetorheological fluid prepared in the present invention is composed of ferromagnetic, paramagnetic particles and oil medium having a diameter larger than 0.1 μm, and when the external magnetic field is applied, the particles are arranged in the inside and the surface of the particles by polarization and the fibers Yield stress is generated by forming a fibril structure and hindering the flow of fluid and improving viscosity. At this time, the yield stress increases with the strength of the magnetic field, and when the shear stress applied is greater than the yield stress of the fluid Fluid will flow. In the magnetorheological body of the present invention, the polymer surrounding the ferromagnetic particles undergoes a foaming process to have porosity, thereby reducing density and increasing stability, thereby significantly reducing the settling speed of the multilayer structure particles. The response speed to the magnetic field of this magnetic fluid is very fast, reversible and stability is improved at the level of milliseconds (10 -3 seconds). Therefore, clutch, engine mount, vibration control device, high-rise building seismic device, and robot It can be widely used in the development of various equipments such as a robotic system.

Claims (6)

  1. (i) 자성입자의 표면에서 단량체를 중합하여 고분자층을 형성시키는 단계;(i) polymerizing monomers on the surface of the magnetic particles to form a polymer layer;
    (ii) 표면에 고분자층이 형성된 자성입자를 압축반응용기에 넣은 후 초임계유체 또는 아임계유체를 이용하여 표면의 고분자층을 발포 시키는 단계; 및(ii) putting the magnetic particles having the polymer layer formed on the surface into a compression reaction vessel, and then foaming the polymer layer on the surface by using a supercritical fluid or a subcritical fluid; And
    (iii) 발포된 고분자층으로 둘러싸인 자성입자를 오일에 5 내지 50%의 무게분율로 분산시키는 단계;를 포함하는 자기유변유체의 제조방법.(iii) dispersing the magnetic particles surrounded by the foamed polymer layer in a weight fraction of 5 to 50% in oil.
  2. 청구항 1에 있어서,The method according to claim 1,
    상기 고분자층은 초임계 또는 아임계상태의 유체가 쉽게 침지될 수 있는 비정형 또는 반결정성 고분자로 이루어진 것을 특징으로 하는 자기유변유체의 제조방법.The polymer layer is a method of producing a magnetorheological fluid, characterized in that consisting of an amorphous or semi-crystalline polymer that can be easily immersed in a supercritical or subcritical fluid.
  3. 청구항 1에 있어서,The method according to claim 1,
    상기 오일은 윤활유, 미네랄오일, 실리콘오일, 캐스터오일, 파라핀오일, 진공 오일, 콘 오일 및 탄화수소 오일로 구성된 그룹으로부터 선택되는 것을 특징으로 하는 자기유변유체의 제조방법.And the oil is selected from the group consisting of lubricating oil, mineral oil, silicone oil, caster oil, paraffin oil, vacuum oil, corn oil and hydrocarbon oil.
  4. 청구항 1에 있어서,The method according to claim 1,
    상기 자성입자는 철, 카보닐철, 철 합금체, 산화철, 질화철, 카바이드철, 저탄소강, 니켈, 코발트, 이들의 혼합물 및 이들의 합금으로 구성된 그룹으로부터 선택되는 것을 특징으로 하는 자기유변유체의 제조방법.The magnetic particles are prepared from a group consisting of iron, carbonyl iron, iron alloy, iron oxide, iron nitride, carbide iron, low carbon steel, nickel, cobalt, mixtures thereof, and alloys thereof. Way.
  5. 청구항 1에 있어서,The method according to claim 1,
    상기 고분자층을 형성하는 단계 이전에 자성입자의 표면을 메타아크릴산, 폴리알콜, 글루코스, 솔비톨, 아미노알콜, 폴리에틸렌글리콜, 아미노옥사이드, 아민염, 4급암모늄염, 피리미딘염, 설포늄염, 포스포늄염,폴리에틸렌폴리아민, 카복실레이트, 설포네이트, 설페이트, 포스페이트, 포스포네이트, 아미노산, 베타인, 아미노설페이트, 설포베타인 및 이들의 혼합물로 전처리하는 단계를 더 포함하는 것을 특징으로 하는 자기유변유체의 제조방법.Before the step of forming the polymer layer, the surface of the magnetic particles is methacrylic acid, polyalcohol, glucose, sorbitol, aminoalcohol, polyethyleneglycol, aminooxide, amine salt, quaternary ammonium salt, pyrimidine salt, sulfonium salt, phosphonium salt Preparation of a magnetorheological fluid further comprising the step of pretreatment with polyethylene polyamine, carboxylate, sulfonate, sulfate, phosphate, phosphonate, amino acid, betaine, aminosulfate, sulfobetain and mixtures thereof. Way.
  6. 청구항 1 내지 청구항 5 중 어느 하나의 방법에 의하여 제조되어, 발포된 고분자층으로 둘러싸인 자성입자가 오일에 5 내지 50%의 무게분율로 분산되어 있는 것을 특징으로 하는 자기유변유체.A magnetorheological fluid prepared by the method of any one of claims 1 to 5, wherein the magnetic particles surrounded by the foamed polymer layer are dispersed in oil at a weight fraction of 5 to 50%.
PCT/KR2015/007555 2014-07-21 2015-07-21 Magnetorheological fluid containing magnetic particles surrounded with foamed polymers and having excellent stability, and method for producing same WO2016013847A1 (en)

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