JPH05295265A - Electroviscous fluid - Google Patents

Abstract

PURPOSE:To obtain an electric viscous fluid having a high shear strength, excellent electric current characteristics, stability with time and dispersibility, comprising a dispersion phase of dielectric material particles, a disperse medium composed of a silicone-based insulating fluid and an additive composed of a silicone- based polymerizable monomer, etc. CONSTITUTION:A dispersion phase composed of dielectric material particles having 1-50mu average particle diameter is dispersed into a disperse medium composed of a silicone-based insulating fluid and 0.1-30 pts.wt. based on 100 pts.wt. dispersion phase of a copolymer of monomer components comprising (A) 3-70wt.% silicone-based polymerizable monomer mainly having a structural unit of formula I (each of R<1> and R<2> is an alkyl or aryl) and/or a structural unit of formula II (R<3> is an alkyl or aryl), having >=400 average molecular weight, (B) 0.5-40wt.% polymerizable monomer having a structural unit of formula III (R<4> is a 2-4C alkylene; (n) is >=4) and/or a structural unit of formula IV (R<5> is H or methyl; X is CN or ester), having >=400 average molecular weight and (C) 0-90wt.% another monomer to give the objective electric viscous fluid.

Description

Detailed Description of the Invention

[0001]

This invention relates to electrorheological fluids. More specifically, a large shear stress is generated even by applying a relatively weak electric field, and the current density that the current density is small at that time is excellent in current characteristics, and the generated shear stress and current density are excellent in stability over time, and The initial viscosity is low when no electric field is applied, and dispersion stability (the ability to keep the electrorheological fluid in a uniform state for a long time without causing the dispersed phase to settle or float) and redispersibility (the dispersed phase to settle or It is related to an electrorheological fluid that is particularly excellent in its ability to reproduce the original uniform state with a simple external force after it has levitated and becomes non-uniform.

[0002]

2. Description of the Related Art An electrorheological fluid is, for example, a fluid obtained by dispersing and suspending solid particles in an insulating dispersion medium, and its rheological or flow properties are viscoplastic due to an electric field change. It is a fluid that changes into mold properties, and is generally known as a fluid exhibiting a so-called Winslow effect, in which the viscosity remarkably rises when an external electric field is applied and large shear stress is induced. Since the Winslow effect is characterized by a quick response, the electrorheological fluid can be applied to engine mounts, clutches, dampers, brakes, shock absorbers, actuators, valves, ink jets, etc. Being tried.

Conventionally, as an electrorheological fluid, it is known that solid particles of cellulose, starch, soybean casein, silica gel or the like are dispersed in an insulating oil such as silicon oil, diphenyl chloride or trans oil. .. However,
Those using cellulose, starch, soybean casein, silica gel, etc. have a problem that the shear stress generated is small.

On the other hand, as an electrorheological fluid which generates a high shearing stress, for example, a powdery substance of an ion exchange resin suspended in a higher alkyl ester of an aromatic carboxylic acid (Japanese Patent Laid-Open No. 50-92278) or 3 A composition comprising a crystalline substance that conducts an electric current along only one of the crystal axes, a dielectric liquid, and a steric stabilizer (JP-A-1-170693) has been proposed. However, these electrorheological fluids are inferior in dispersion stability when no electric field is applied and in redispersibility after once settling or floating, and when the viscosity of the dispersion medium is increased or dispersed so that the dispersed phase does not separate. When the phase concentration is increased, there is a problem that the fluidity becomes poor.

As an example of an attempt to improve dispersion stability, an electrorheological fluid having silica gel as a dispersion phase is used as a dispersion medium having a nitrogen atom and / or a hydroxyl group-containing group and an alkyl group having 4 to 24 carbon atoms. A method of adding a soluble polymer (Japanese Patent Laid-Open No. 61-259752) or a method of adding polysiloxane such as amino-functionality to an electrorheological fluid containing silica gel or aluminum silicate as a dispersion phase and silicon oil as a dispersion medium (special KAISHO 61-44998, JP-A-62-95
397) has been proposed. However, these electrorheological fluids have problems that not only the generated shear stress is small, but also the initial viscosity is high.

In order to improve redispersibility, electrorheological fluids containing fine particles (JP-A-3-166295 and JP-A-3-160094) have been proposed. However, these electrorheological fluids are inferior in dispersion stability when no electric field is applied, and there is a problem that performance as an electrorheological fluid becomes unstable.

Therefore, the electrorheological fluids that have been reported so far have a large shear stress generated, excellent stability of the generated shear stress and current density with time, a low initial viscosity, dispersion stability and reusability. The excellent dispersibility is not satisfied at the same time, and it is not practical in a wide range of applications.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of conventional electrorheological fluids.

Therefore, an object of the present invention is to generate a large shear stress even when a relatively weak electric field is applied, and the current density flowing at that time is small. Excellent stability over time, low initial viscosity when no electric field is applied, dispersion stability (ability to keep electrorheological fluid in a uniform state for a long time without causing the dispersed phase to settle or float), and redispersion The purpose of the present invention is to provide an electrorheological fluid that is particularly excellent in the property (the ability to reproduce the original uniform state with a simple external force after the dispersed phase has settled or floated and becomes non-uniform).

[0010]

The present invention relates to an electrorheological fluid containing a dispersed phase composed of dielectric particles having an average particle size of 1 to 50 μm, a dispersion medium composed of a silicon-based insulating liquid, and an additive. Therefore, as an additive, a structural unit (a) represented by the general formula:-(SiR ¹ R ² O)-(wherein R ¹ and R ² are each independently an alkyl group or an aryl group). And / or having a structural unit (b) represented by the general formula (R ³ ₃ SiO) ₃ Si— (wherein R ³ is an alkyl group or an aryl group) as a main constituent unit, and having an average molecular weight of 3 to 70% by weight of a silicone-based polymerizable monomer (A) of 400 or more, a general formula — (R ⁴ —O) n — (wherein, R ⁴ is an alkylene group having 2 to ⁴ carbon atoms, n is a number of 4 or more.) and / or structural unit (c) General formula ^{_{- (CH 2 -CR 5 X)}} - ( provided that wherein R ⁵ is hydrogen or methyl, X is -
CN or -COOR ^6, R ⁶ is an alkyl group having 1 to 4 carbon atoms. ) 0.5 to 40% by weight of a polymerizable monomer (B) having a structural unit (d) represented by the formula (b) as a main constituent unit and an average molecular weight of 400 or more, and other polymerizable monomers (C). ) 0 to 90% by weight (however, the total of the monomers (A), (B) and (C) is 100% by weight) A copolymer (I) obtained by polymerizing a monomer component. ) Is used in the range of 0.1 to 30 parts by weight with respect to 100 parts by weight of the dispersed phase.

[0011]

The average particle size of the dielectric particles forming the dispersed phase of the electrorheological fluid of the present invention must be within the range of 1 to 50 μm. When the average particle size of the dispersed phase is less than 1 μm, a large shear stress cannot be obtained when an electric field is applied to the prepared electrorheological fluid. The average particle size of the dielectric particles is 5
If it exceeds 0 μm, an electrorheological fluid having excellent dispersion stability without applying an electric field cannot be obtained.

The dielectric particles used as the dispersed phase of the electrorheological fluid of the present invention are not limited as long as they are particles that polarize in the state of applying an electric field, and they include any of ion polarization type, dipole polarization type, electronic polarization type, interface polarization type and the like. Particles of type may be used. Examples of such particles include particles of an organic polymer or an inorganic material having an ion exchange ability, particles of an inorganic dielectric material composed of two or more kinds of atoms having greatly different electronegativities, a hydroxyl group, an amino group, an amide group or a carbonyl group. Examples include organic polymer particles containing functional groups having polarities such as, and composite particles in which the surface of a conductor such as metal or carbon has been subjected to insulation treatment. The organic polymer particles it has are preferable, and among them, particles made of a sulfonic acid group-containing polystyrene polymer are particularly preferable.

The sulfonic acid group-containing polystyrene polymer has a cation which can be dissociated in the presence of a polar solvent such as water, but the kind of the cation is not particularly limited. Metal cations such as lithium ion, sodium ion, potassium ion, calcium ion, magnesium ion, aluminum ion, cuprous ion and cupric ion; organic cations such as tetramethylammonium ion and pyridinium ion You can

The method for obtaining the dielectric particles which can be used as the dispersed phase in the present invention is not particularly limited, and the particles can be synthesized by a known method, or commercially available ones can be used as they are, or after-treatment such as crushing can be performed as necessary. Is also good.

It is necessary to use a silicon-based insulating liquid as the dispersion medium of the electrorheological fluid of the present invention. The silicon-based insulating liquid that can be used as the dispersion medium is essentially composed of silicon oil. There is no particular limitation as long as it is an electrically insulating liquid, and examples thereof include polydimethylsiloxanes such as polydimethylsiloxane, partially octyl-substituted polydimethylsiloxane, and partially phenyl-substituted polydimethylsiloxane; silicone oils such as polydiphenylsiloxanes. And it is possible to use one or more of these. Further, if necessary, a mixture of a hydrocarbon-based insulating liquid such as cyclohexylbenzene or dodecylbenzene or another insulating liquid such as a halogen-containing insulating liquid within 50% by weight of the dispersion medium is used. be able to.

Generally, the dispersion stability of an electrorheological fluid is largely dependent on the interaction between the dispersed phase and the additive in the dispersed state, and therefore it is necessary for the additive to have a large adsorption capacity for the dispersed phase. is there. On the other hand, the greater the interaction between the disperse phases or the disperse phase and the additive in the sedimentation layer after the disperse phase has settled, the worse the redispersibility. It is necessary to reduce the density.

The present invention has been achieved as a result of a study conducted to realize such a seemingly contradictory adsorption behavior of an additive to a dispersed phase in a silicon-based insulating liquid. That is, the additive used in the present invention is a block of a silicon-based structural unit having a high affinity for the silicon-based insulating liquid of the dispersion medium and a structural unit containing a nitrogen atom and / or an oxygen atom having a high affinity for the dispersed phase. It is a copolymer having a block and swelling partially or wholly in a silicon-based insulating liquid. Such a copolymer can improve the dispersion stability and redispersibility of an electrorheological fluid. It turned out to be effective.

Therefore, the additive used in the electrorheological fluid of the present invention is the structural unit (a) represented by the above general formula.
And / or a silicon-based polymerizable monomer (A) having a structural unit (b) as a main constituent unit and an average molecular weight of 400 or more, the structural unit (c) and / or the structural unit represented by the general formula. Obtained by polymerizing a monomer component comprising (d) as a main constituent unit and having an average molecular weight of 400 or more and a polymerizable monomer (B) and optionally other polymerizable monomer (C). It is a copolymer (I).

The copolymer (I) used as an additive for the electrorheological fluid of the present invention comprises, as a raw material monomer, the above-mentioned silicone-based polymerizable monomer (A) in an amount of 3 to 3 in all monomer components. 70% by weight
It is necessary to use in the range of. When the amount of the silicon-based polymerizable monomer (A) used is less than 3% by weight or more than 70% by weight, it is impossible to greatly improve the dispersion stability of the prepared electrorheological fluid.

The content of the structural unit (a) and / or the structural unit (b) in the silicon-based polymerizable monomer (A) is not particularly limited, but it is converted into silicon atoms and the silicon-based polymerizable unit amount is converted. It is preferably 20% by weight or more in the body (A).

Such a silicon-based polymerizable monomer (A)
Examples thereof include vinyl group-containing polydimethylsiloxane, (meth) acryloyl group-containing polydimethylsiloxane, styryl group-containing polydimethylsiloxane, vinyl group-containing partially octyl-substituted polydimethylsiloxane, and (meth) acryloyl group-containing partially octyl-substituted polydimethylsiloxane. , Styryl group-containing partial octyl-substituted polydimethylsiloxane, vinyl group-containing partial phenyl-substituted polydimethylsiloxane, (meth) acryloyl group-containing partial phenyl-substituted polydimethylsiloxane, styryl group-containing partial phenyl-substituted polydimethylsiloxane and tris (trimethylsiloxy) silyl Propyl (meth) acrylate and the like can be mentioned, and among these, one kind or two or more kinds can be used.

The copolymer (I), which is an additive for the electrorheological fluid of the present invention, contains the polymerizable monomer (B) as a raw material monomer in an amount of 0.5 to 0.5% based on the total monomer components. It is necessary to use in the range of 40% by weight. When the amount of the polymerizable monomer (B) used is less than 0.5% by weight or more than 40% by weight, it is impossible to greatly improve the dispersion stability of the prepared electrorheological fluid.

The content of the structural unit (c) and / or the structural unit (d) in the polymerizable monomer (B) is not particularly limited, but the polymerizable monomer is converted into nitrogen atom and / or oxygen atom. It is preferably 5% by weight or more in the body (B).

As such a polymerizable monomer (B),
For example, (meth) acryloyl group-containing polyethylene glycol, styryl group-containing polyethylene glycol, p-isopropenylbenzyl group-containing polyethylene glycol,
(Meth) acryloyl group-containing polypropylene glycol, styryl group-containing polypropylene glycol, p-isopropenylbenzyl group-containing polypropylene glycol, (meth) acryloyl group-containing polytetramethylene glycol, styryl group-containing polytetramethylene glycol, p-isopropenylbenzyl group Containing polytetramethylene glycol and other polyalkylene glycols having a polymerizable double bond; (meth) acryloyl group-containing poly (meth) acrylate, styryl group-containing poly (meth) acrylate, p-vinylbenzyl group-containing Poly (meth) acrylate, p-isopropenylbenzyl group-containing poly (meth) acrylate, allyl group-containing poly (meth) acrylate, (meth) acryloyl group-containing poly (meth) acrylate Butyl Le acid, p- vinylbenzyl group-containing poly (meth) butyl acrylate, p- isopropenyl benzyl group-containing poly (meth) acrylate, butyl (meth) acryloyl group-containing (acrylonitrile -
Examples thereof include (meth) acrylic acid ester-based polymers and acrylonitrile-based polymers having a polymerizable double bond such as styrene) copolymers, and one or more of them can be used. ..

The copolymer (I), which is an additive for the electrorheological fluid of the present invention, contains the other polymerizable monomer (C) as the raw material monomer in an amount of 90% by weight or less based on the total monomer components. It can be used in the range of.

As such a polymerizable monomer (C),
For example, olefins such as ethylene, propylene, butylene, pentene, hexene, heptene, octene, cyclopentene, cyclohexene; vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride, vinylene chloride, odor Halogenated olefins such as vinyl chloride; alkyl dienes such as butadiene, isoprene and cyclopentadiene;
Styrene, methylstyrene, ethylstyrene, propylstyrene, butylstyrene, pentylstyrene, vinylnaphthalene, methylvinylnaphthalene, ethylvinylnaphthalene, propylvinylnaphthalene, butylvinylnaphthalene, pentylvinylnaphthalene, hexylvinylnaphthalene, vinylanthracene, methylvinylanthracene , Ethyl vinyl anthracene, propyl vinyl anthracene, butyl vinyl anthracene, pentyl vinyl anthracene, hexyl vinyl anthracene, vinyl phenanthrene, methyl vinyl phenanthrene, ethyl vinyl phenanthrene, propyl vinyl phenanthrene, butyl vinyl phenanthrene, pentyl vinyl phenanthrene, hexyl vinyl phenanthrene, fluorostyrene , Chloros Ren, bromostyrene, dichloro styrene, trichloro styrene, tetra-chlorostyrene, chloromethylstyrene, hydroxymethylstyrene, aminomethyl styrene, chloro-vinyl naphthalene,
Aryl alkenes such as chlorovinylanthracene and chlorovinylphenanthrene; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth ) (Meth) acrylic acid esters such as hexyl acrylate and hydroxyethyl (meth) acrylate; (meth) acrylamides such as (meth) acrylamide and dimethyl (meth) acrylamide; methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, pentyl Vinyl ethers such as vinyl ether and hexyl vinyl ether; vinyl esters such as vinyl acetate, vinyl trifluoroacetate and vinyl pentafluoropropionate; allyl acetate, allyl acetonitrile, ant Polymerizable substituted allyls such as alcohol, allylamine, diallylamine, triallylamine, allyl cyanide, diallyl ether, allyl ethyl ether, allyl toluyl ether; dimethyl fumarate, diethyl fumarate, dibutyl fumarate, diphenyl fumarate, diamyl fumarate, etc. Fumaric acid esters of
Maleic acid esters such as dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, diamyl maleate and diphenyl maleate;
(Meth) acrolein, chloro (meth) acrolein,
Unsaturated aldehydes such as crotonaldehyde; Unsaturated ketones such as methyl vinyl ketone and ethyl vinyl ketone;
Unsaturated lactams such as vinylpyrrolidone; Unsaturated amines such as dimethylvinylamine and diethylvinylamine;
Unsaturated nitriles such as (meth) acrylonitrile and cyanovinylidene; divinylbenzene, vinylpropenylbenzene, vinylisopropenylbenzene, vinylisobutenylbenzene, diisopropenylbenzene, isopropenylisobutenylbenzene, diisobutenylbenzene, divinylmethyl Benzene, divinylethylbenzene, divinyldimethylbenzene, trivinylbenzene,
Polyfunctional aromatic compounds such as triisopropylbenzene, divinylnaphthalene, vinylisopropylnaphthalene, diisopropylnaphthalene, divinylanthracene and divinylphenanthrene; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) )
Acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) Acrylate,
1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate
Acrylate, dipentaerythritol penta (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth)
Acrylate, glycerol di (meth) acrylate,
Polyfunctional polymerizable (meth) acrylate derivatives such as tetramethylolmethane tri (meth) acrylate and tetramethylolmethane tetra (meth) acrylate; N, N′-
Methylenebis ((meth) acrylamide), N, N'-
Polyfunctional polymerizable (meth) acrylamide derivatives such as ethylene bis ((meth) acrylamide); Polyfunctional polymerizable allyl derivatives such as diethylene glycol diallyl ether, diallyl chlorendate, diallyl phthalate, diallyl hexahydrophthalate, triallyl trimellitate And the like, and one or more of them can be used. Among these other polymerizable monomers (C), arylalkenes such as styrene and divinylbenzene are particularly preferable in terms of polymerization reactivity and performance of the electrorheological fluid obtained.

The method for obtaining the copolymer (I) as an additive for the electrorheological fluid of the present invention is not particularly limited, and for example, a silicone-based polymerizable monomer (A), a polymerizable monomer (B) and If necessary, a radical polymerization method is used in which a monomer component composed of another polymerizable monomer (C) is optionally used with a polymerization catalyst such as a peroxide, an azo compound or a redox system, and other additives. it can. As the polymerization form, known polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, dispersion polymerization, precipitation polymerization and suspension polymerization can be used. Among them, solution polymerization in alcoholic solvent, dispersion polymerization or precipitation It is preferable from the viewpoint of the performance of an electrorheological fluid using a copolymer obtained by a polymerization method such as polymerization. Further, after the polymerization, if necessary, post-treatment can be carried out by a known method such as reprecipitation purification, solvent substitution, solvent distillation, drying or pulverization. In particular, when the polymerization solvent is replaced with silicone oil to prepare a silicone oil dispersion of the copolymer (I) and then used as an additive,
It is preferable because workability in preparing the electrorheological fluid is improved.

The copolymer (I) used as an additive in the electrorheological fluid of the present invention is 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the dispersed phase. It is necessary to use. When the amount of the polymer dispersant used is less than 0.1 part by weight based on the dispersed phase, the dispersion stability of the electrorheological fluid cannot be sufficiently improved. On the other hand, if it exceeds 30 parts by weight, dispersion stability commensurate with the amount added may not be obtained, or the initial viscosity of the electrorheological fluid may remarkably increase, causing practical problems.

The electrorheological fluid of the present invention is prepared by mixing and dispersing the above-mentioned dielectric particles as a dispersed phase in a dispersion medium made of a silicon-based insulating liquid in the presence of the copolymer (I) as an additive. Is what you get.

The ratio of the dispersed phase to the dispersion medium in the electrorheological fluid of the present invention is 50 to 5 for the former 100 parts by weight.
It is preferably in the range of 00 parts by weight. When the amount of the dispersion medium exceeds 500 parts by weight, the shear stress obtained when an electric field is applied to the prepared electrorheological fluid may not be sufficiently large. Further, when the amount of the dispersion medium is less than 50 parts by weight, the fluidity of the prepared composition itself may be lowered, and it may be difficult to use it as an electrorheological fluid.

The electrorheological fluid of the present invention contains, for example, known polymer dispersants, surfactants, polymer thickeners, fine particles and other additives in order to adjust the viscosity or improve the shear stress. Various conventionally known additives can be added.

[0032]

The present invention will be described below with reference to examples, but the scope of the present invention is not limited to these examples.

[0033]

[Reference Example 1] A 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube was charged with 567 g of isopropyl alcohol, 6 g of azobisisobutyronitrile, and a silicone-based polymerizable monomer (A). Methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight = about 500)
0, silicon content = 36%) 30 g, methacryloyl group-containing methoxy polyethylene glycol as a polymerizable monomer (B) (NK ester M-230G manufactured by Shin-Nakamura Chemical Co., Ltd., degree of polymerization of polyethylene glycol n = (Approximately 23, average molecular weight = approximately 1100, oxygen content = 37%)
10 g, styrene 4 as other polymerizable monomer (C)
0 g and 20 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene and 35% by weight of ethylstyrene manufactured by Wako Pure Chemical Industries, Ltd.) were added and stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 65 ° C. for 20 hours and further at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. 20c in this reaction solution
s silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.)
-20 cs) 400 g was added dropwise, the volatile matter was distilled off by heating under reduced pressure with an evaporator, and the silicone oil dispersion liquid of the copolymer (1) (content of the copolymer (1) was 20% by weight, Hereinafter, an additive dispersion liquid (1) was obtained.

[0034]

Reference Example 2 In a 2000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 700 g of isopropyl alcohol, 6 g of azobisisobutyronitrile, 5 g of polyvinylpyrrolidone, and a silicone-based polymerizable monomer were used. (A) Methacryloyl group-containing polydimethylsiloxane (Cilaplane FM071 manufactured by Chisso Corporation)
1, average molecular weight = about 1000, silicon content = 33%)
7 g, polyethylene glycol containing a methacryloyl group as a polymerizable monomer (B) (Blenmer PE-350 manufactured by NOF CORPORATION, polymerization degree of polyethylene glycol = 7)
~ 9, average molecular weight = about 450, oxygen content = 37%)
1.5 g, 90.5 g of styrene as other polymerizable monomer (C) and 3 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene, 35% by weight of ethylstyrene, manufactured by Wako Pure Chemical Industries, Ltd.) Was charged and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 65 ° C. for 20 hours and further at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. 10c in this reaction solution
s silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.)
-10 cs) 400 g was added dropwise, the volatile matter was distilled off by heating under reduced pressure with an evaporator, and a silicone oil dispersion liquid of the copolymer (2) (copolymer (2) content 20% by weight, Hereinafter, an additive dispersion liquid (2) was obtained.

[0035]

[Reference Example 3] A 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube was charged with 567 g of isopropyl alcohol, 5 g of azobisisobutyronitrile, and a silicone-based polymerizable monomer (A). Methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0725 manufactured by Chisso Corporation, average molecular weight = about 1000)
0, silicon content = 37%) 60 g, methacryloyl group-containing polyethylene glycol tetraethylene glycol (Blenmer 55 PET-800 manufactured by NOF CORPORATION) as a polymerizable monomer (B), degree of polymerization of polyethylene glycol = 10, Polymerization degree of polytetramethylene glycol = 5, average molecular weight = about 900, oxygen content = 31%)
30 g and 10 g of industrial divinylbenzene (mixture of divinylbenzene 55% by weight, ethylstyrene 35% by weight, manufactured by Wako Pure Chemical Industries, Ltd.) as another polymerizable monomer (C) were charged and nitrogen was blown into the mixture. The mixture was stirred at room temperature for 30 minutes. This is heated at 65 ° C for 20 hours and further heated at 83 ° C.
Polymerization reaction was carried out by heating for 4 hours. The solid content of the obtained reaction solution was measured and the polymerization rate of the monomer was measured to be 98.
%was. After 392 g of 20 cs silicon oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, the volatile components were distilled off by heating under reduced pressure with an evaporator to obtain a copolymer (3). A silicone oil dispersion (content of copolymer (3): 20% by weight, hereinafter referred to as additive dispersion (3)) was obtained.

[0036]

Reference Example 4 In a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 300 g of isopropyl alcohol, 267 g of toluene, 3 g of benzoyl peroxide, and a silicon-based polymerizable monomer (A) were used. Methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0725 manufactured by Chisso Corporation, average molecular weight =
Approximately 10,000, silicon content = 37%) 15 g, methacryloyl group-containing (acrylonitrile-styrene) copolymer as a polymerizable monomer (B) (Toa Synthetic Chemical Industry Co., Ltd.)
Manufactured by Macromonomer AN-6, average molecular weight = about 600
0, nitrogen content = 5.8%), 70 g of styrene as another polymerizable monomer (C) and 10 g of diallyl phthalate were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 20 hours and further at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, which was 100.
%was. After 400 g of 20 cs silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, the volatile components were distilled off by heating under reduced pressure with an evaporator to obtain a copolymer (4). A silicone oil dispersion liquid (copolymer (4) content 20% by weight, hereinafter referred to as additive dispersion liquid (4)) was obtained.

[0037]

[Reference Example 5] 400 g of isopropyl alcohol, 167 g of toluene, 4 g of azobisisobutyronitrile, and 4 g of a silicone-based polymerizable monomer were placed in a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. A) Tris (trimethylsiloxy) silylpropyl methacrylate (X-22 manufactured by Shin-Etsu Chemical Co., Ltd.)
-5002, molecular weight = about 422, silicon content = 26
%) 30 g, polymethyl methacrylate containing a methacryloyl group as a polymerizable monomer (B) (macromonomer AA-6 manufactured by Toagosei Kagaku Kogyo Co., Ltd., average molecular weight = about 6).
000, oxygen content by elemental analysis = 32%) 10 g,
50 g of styrene and 10 g of hexamethylene dimethacrylate were added as other polymerizable monomers (C), and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. 65 ° C
At 20 ° C. for 20 hours and then at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. After 400 g of 20 cs silicone oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, the volatile components were distilled off by heating under reduced pressure with an evaporator to obtain a copolymer (5). Silicon oil dispersion (Copolymer (5)
Content of 20% by weight, hereinafter referred to as additive dispersion (5).

[0038]

Reference Example 6 In a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 400 g of isopropyl alcohol, 4 g of azobisisobutyronitrile, and a silicone-based polymerizable monomer (A) were used. Methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight = about 500)
0, silicon content = 36%) 30 g, polybutyl acrylate containing methacryloyl group as a polymerizable monomer (B) (macromonomer AB manufactured by Toagosei Kagaku Kogyo Co., Ltd.)
-6, average molecular weight = about 6000, oxygen content = 28%)
20 g, styrene 4 as other polymerizable monomer (C)
0 g and 10 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene and 35% by weight of ethylstyrene manufactured by Wako Pure Chemical Industries, Ltd.) were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 65 ° C. for 20 hours and further at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. 20c in this reaction solution
s silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.)
-20 cs) 400 g was added dropwise, the volatile components were distilled off by heating under reduced pressure with an evaporator, and a silicone oil dispersion liquid of the copolymer (6) (content of the copolymer (6) 20% by weight, Hereinafter, an additive dispersion liquid (6) was obtained.

[0039]

[Reference Example 7] A 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube was charged with 567 g of isopropyl alcohol, 6 g of azobisisobutyronitrile, and a silicone-based polymerizable monomer (A). Methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight = about 500)
0, silicon content = 36%) 30 g, methacryloyl group-containing methoxy polyethylene glycol as a polymerizable monomer (B) (NK Ester M- manufactured by Shin Nakamura Chemical Co., Ltd.)
230G, degree of polymerization of polyethylene glycol = about 23,
Average molecular weight = about 1100, oxygen content = 37%) 10g
And styrene 60 as other polymerizable monomer (C)
g was added and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 65 ° C. for 20 hours and further at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. After 400 g of 20 cs silicone oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, the volatile components were distilled off by heating under reduced pressure with an evaporator to obtain a copolymer (7). A silicone oil dispersion (content of copolymer (7): 20% by weight, hereinafter referred to as additive dispersion (7)) was obtained.

[0040]

[Reference Example 8] In a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 567 g of isopropyl alcohol, 6 g of azobisisobutyronitrile, methoxypolyethylene glycol containing methacryloyl group (Shin Nakamura Chemical ( KK ester NK ester M-230
G, degree of polymerization of polyethylene glycol = about 23, average molecular weight = about 1100, oxygen content = 37%) 10 g, styrene 70 g and industrial divinylbenzene (manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene 55% by weight, ethyl) 20 g of a mixture of styrene (35% by weight) and the like were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. 20 at 65 ℃
The mixture was heated for 3 hours and further heated at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. 20 in this reaction mixture
cs silicone oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.)
6-20 cs) 400 g was added dropwise, the volatile components were distilled off by heating under reduced pressure with an evaporator, and the silicone oil dispersion liquid of the copolymer (8) (content of the copolymer (8) was 20% by weight). Hereinafter referred to as comparative additive dispersion (1))
Got

[0041]

[Reference Example 9] In a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 567 g of isopropyl alcohol, 6 g of azobisisobutyronitrile, 5 g of polyvinylpyrrolidone, and polydimethylsiloxane containing a methacryloyl group ( Cilaplane FM0721 manufactured by Chisso Co., average molecular weight = about 5000, silicon content = 36%) 30 g, styrene 40 g and industrial divinylbenzene (Wako Pure Chemical Industries, Ltd., divinylbenzene 55% by weight, ethyl) 20 g of a mixture of styrene (35% by weight) and the like were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This is heated at 65 ° C for 20 hours and further heated at 83 ° C.
Polymerization reaction was carried out by heating for 4 hours. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, which was 10
It was 0%. 20 cs of silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) 400 was added to the reaction solution.
After g was added dropwise, the volatile matter was distilled off by heating under reduced pressure with an evaporator, and the silicone oil dispersion liquid of the copolymer (9) (content of the copolymer (9) was 20% by weight,
A comparative additive dispersion liquid (2) was obtained.

[0042]

Reference Example 10 400 g of ion-exchanged water, 4 g of sodium dodecyl sulfonate and 1 g of sodium persulfate were charged and dissolved in a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. To this, a monomer component consisting of 70 g of styrene and 30 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene, 35% by weight of ethylstyrene, manufactured by Wako Pure Chemical Industries, Ltd.) was added and dispersed while blowing nitrogen. 200 by machine
The mixture was stirred at 00 rpm for 2 minutes. This was heated at 70 ° C. for 3 hours and further heated at 90 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. Water was distilled off by heating the reaction solution under reduced pressure with an evaporator and then dried in an air oven at 80 ° C. overnight to obtain a fine particle copolymer (1
0) (hereinafter referred to as comparative additive (3)). The average particle diameter of the comparative additive (3) measured by an electron micrograph was 0.1 μm.

[0043]

[Reference Example 11] 400 g of ion-exchanged water and 5 g of polyvinyl alcohol (Kuraray Poval PVA-205 manufactured by Kuraray Co., Ltd.) were placed in a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. Then, 2 g of benzoyl peroxide was added to a monomer component consisting of 70 g of styrene and 30 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene, 35% by weight of ethylstyrene, manufactured by Wako Pure Chemical Industries, Ltd.). The solution obtained by dissolution was added. The mixture was stirred at 15000 rpm for 30 minutes while blowing nitrogen and then heated at 70 ° C. for 8 hours and further heated at 90 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, and it was 100%. The solid content in the reaction solution is separated by filtration, thoroughly washed with acetone and water, and then dried in an air oven at 80 ° C. overnight to obtain a fine particle copolymer (11).
(Hereinafter, referred to as comparative additive (4)) was obtained. The average particle diameter of the comparative additive (4) measured by an electron micrograph was 1 μm.

[0044]

[Reference Example 12] 400 g of isopropyl alcohol, 4 g of azobisisobutyronitrile, and a silicone-based polymerizable monomer (A) were placed in a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. Methacryloyl group-containing polydimethyl siloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight = about 500)
0, silicon content = 36%) 28 g, methacryloyl group-containing methoxy polyethylene glycol as a polymerizable monomer (B) (NK Ester M- manufactured by Shin Nakamura Chemical Co., Ltd.)
230G, degree of polymerization of polyethylene glycol = about 23,
Average molecular weight = about 1100, oxygen content = 37%) 12
g, styrene 45 as other polymerizable monomer (C)
g, diallyl phthalate 10 g and butyl methacrylate 5 g were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 65 ° C. for 20 hours and further at 83 ° C. for 4 hours to carry out a polymerization reaction. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, which was 100.
%was. After 400 g of 20 cs silicon oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, the volatile components were distilled off by heating under reduced pressure with an evaporator to obtain a copolymer (12). Silicon oil dispersion (copolymer (12) content 20% by weight,
An additive dispersion liquid (8) was obtained.

[0045]

Example 1 1200 g of ion-exchanged water and 16 g of polyvinyl alcohol (Kuraray Poval PVA-205 manufactured by Kuraray Co., Ltd.) were added to a 3000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. -After being dissolved, 250 g of styrene, divinylbenzene for industrial use (manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene 5)
5% by weight, a mixture of 35% by weight of ethylstyrene, etc.) 50
g and 5 g of benzoyl peroxide were added. Then, the contents of the flask were dispersed using a disperser (rotation speed: 4000 rpm), and heated at 70 ° C for 6 hours and further at 90 ° C for 2 hours. The obtained solid matter was separated by filtration, washed sufficiently with acetone and water, and then dried at 80 ° C. for 12 hours using a hot air drier to obtain a polymerized crosslinked body (hereinafter, referred to as polymerized crosslinked body (1). ) 291 g were obtained.

Next, 500 g of 98% by weight concentrated sulfuric acid was charged into a 1000 ml three-necked flask equipped with a stirrer, a reflux condenser and a thermometer, and the crosslinked polymer (1) 10 was cooled with ice.
0 g was added, and the mixture was heated at 80 ° C. for 24 hours with stirring to carry out a sulfonation reaction. Then, the contents of the flask were poured into water at 0 ° C., and filtered and washed with water.

The solid obtained was neutralized with 380 ml of a 10% by weight aqueous sodium hydroxide solution, and then thoroughly washed with water. Then, it was dried at 80 ° C. for 10 hours using a vacuum dryer, and organic polymer particles having an average particle diameter of 11 μm {hereinafter, referred to as dispersed phase particles (1). } 187g was obtained. In addition,
The anionic dissociative group density of the dispersed phase particles (1) is 4.2 mg.
It was equivalent / g.

After 30 g of dispersed phase particles (1) were dried at 150 ° C. for 3 hours and allowed to stand in a room at a temperature of 20 ° C. and a relative humidity of 60% for 30 minutes to absorb moisture, the additive dispersion obtained in Reference Example 1 was dispersed. 15 g of the liquid (1) was added to 55 g of 20 cs of silicone oil (KF96-20cs of Shin-Etsu Chemical Co., Ltd.) to uniformly disperse it in a dispersion medium to obtain an electrorheological fluid (1) of the present invention. It was

[0049]

Example 2 35 g of the additive dispersion (2) obtained in Reference Example 2 was used in place of the additive dispersion (1) in Example 1, and 10 cs of silicon oil (Shin-Etsu was used instead of 20 cs of silicon oil). KF96-1 manufactured by Chemical Industry Co., Ltd.
(0 cs) 35 g was used to obtain an electrorheological fluid (2) of the present invention in the same manner as in Example 1.

[0050]

[Example 3] 2.5 g of the additive dispersion (3) obtained in Reference Example 3 instead of the additive dispersion (1) in Example 1
Silicone oil (KF manufactured by Shin-Etsu Chemical Co., Ltd.)
The electrorheological fluid (3) of the present invention was obtained by the same method as in Example 1 except that the amount of 96-20 cs) used was changed to 67.5 g.

[0051]

Example 4 20 g of the additive dispersion liquid (4) obtained in Reference Example 4 was used in place of the additive dispersion liquid (1) in Example 1, and silicon oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
The electrorheological fluid (4) of the present invention was prepared in the same manner as in Example 1 except that the amount of 6-20 cs) used was changed to 50 g.
Got

[0052]

Example 5 10 g of the additive dispersion liquid (5) obtained in Reference Example 5 was used in place of the additive dispersion liquid (1) in Example 1, and silicon oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
The electrorheological fluid (5) of the present invention was prepared in the same manner as in Example 1 except that the amount of 6-20 cs) used was changed to 60 g.
Got

[0053]

Example 6 10 g of the additive dispersion liquid (6) obtained in Reference Example 6 was used in place of the additive dispersion liquid (1) in Example 1, and silicon oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
The electrorheological fluid (6) of the present invention was prepared in the same manner as in Example 1 except that the amount of 6-20 cs) used was changed to 60 g.
Got

[0054]

Example 7 15 g of the additive dispersion liquid (7) obtained in Reference Example 7 was used in place of the additive dispersion liquid (1) in Example 1, and silicon oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
The electrorheological fluid (7) of the present invention was prepared in the same manner as in Example 1 except that the amount of 6-20 cs) used was changed to 60 g.
Got

[0055]

Example 8 1200 g of ion-exchanged water and 16 g of polyvinyl alcohol (Kuraray Poval PVA-205 manufactured by Kuraray Co., Ltd.) were added to a 3000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. -After being dissolved, 250 g of styrene, divinylbenzene for industrial use (manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene 5)
5% by weight, a mixture of 35% by weight of ethylstyrene, etc.) 50
g and 5 g of benzoyl peroxide were added. Then, the content of the flask was dispersed using a disperser (rotation speed: 20000 rpm), and the mixture was heated at 70 ° C for 6 hours and further at 90 ° C for 2 hours. The obtained solid matter was filtered off, washed sufficiently with acetone and water, and then dried at 80 ° C. for 12 hours using a hot air drier to obtain a polymerized crosslinked body (hereinafter, referred to as polymerized crosslinked body (2). ) 278 g were obtained.

Then, 500 g of 98% by weight concentrated sulfuric acid was charged into a 1000 ml three-necked flask equipped with a stirrer, a reflux condenser and a thermometer, and the crosslinked polymer (2) 10 was cooled with ice.
0 g was added, and the mixture was heated at 80 ° C. for 24 hours with stirring to carry out a sulfonation reaction. Then, the contents of the flask were poured into water at 0 ° C., and filtered and washed with water.

The solid thus obtained was neutralized with 370 ml of a 10% by weight sodium hydroxide aqueous solution and then thoroughly washed with water. Then, it was dried at 80 ° C. for 10 hours using a vacuum dryer, and organic polymer particles having an average particle diameter of 2.7 μm {hereinafter, referred to as dispersed phase particles (2). } 181g was obtained. The anionic dissociative group density of the dispersed phase particles (2) was 4.3.
It was mg equivalent / g.

After 30 g of the dispersed phase particles (2) were dried at 150 ° C. for 3 hours and allowed to stand for 20 minutes in a room at a temperature of 20 ° C. and a relative humidity of 60% to absorb moisture, the additive dispersion obtained in Reference Example 1 was dispersed. 15 g of the liquid (1) was added to 55 g of 20 cs of silicone oil (KF96-20cs of Shin-Etsu Chemical Co., Ltd.) to uniformly disperse it in a dispersion medium to obtain an electrorheological fluid (8) of the present invention. It was

[0059]

Example 9 1200 g of ion-exchanged water and 12 g of polyvinyl alcohol (Kuraray Poval PVA-205 manufactured by Kuraray Co., Ltd.) were added to a 3000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. -After being dissolved, 250 g of styrene, divinylbenzene for industrial use (manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene 5)
5% by weight, a mixture of 35% by weight of ethylstyrene, etc.) 50
g and 5 g of benzoyl peroxide were added. Then, the contents of the flask were dispersed at 600 rpm, heated at 70 ° C for 6 hours, and further heated at 90 ° C for 4 hours. The obtained solid matter was separated by filtration, washed sufficiently with acetone and water, and then dried at 80 ° C. for 12 hours using a hot air drier to obtain a polymerized crosslinked body (hereinafter, referred to as polymerized crosslinked body (3). ) 294 g were obtained.

Next, 500 g of 98% by weight concentrated sulfuric acid was charged into a 1000 ml three-necked flask equipped with a stirrer, a reflux condenser and a thermometer, and the crosslinked polymer (3) 10 was cooled with ice.
0 g was added, and the mixture was heated at 80 ° C. for 24 hours with stirring to carry out a sulfonation reaction. Then, the contents of the flask were poured into water at 0 ° C., and filtered and washed with water.

The solid obtained was neutralized with 370 ml of a 10% by weight sodium hydroxide aqueous solution and then thoroughly washed with water. Then, it was dried at 80 ° C. for 10 hours using a vacuum dryer, and organic polymer particles having an average particle diameter of 28 μm {hereinafter, referred to as dispersed phase particles (3). } 188g was obtained. The density of the anionic dissociative groups of the dispersed phase particles (3) was 4.2.
It was mg equivalent / g.

After 32 g of the dispersed phase particles (3) were dried at 150 ° C. for 3 hours and allowed to stand for 40 minutes in a room at a temperature of 20 ° C. and a relative humidity of 60% to absorb moisture, the additive dispersion obtained in Reference Example 1 was dispersed. 10 g of the liquid (1) was added to 58 g of 20 cs of silicone oil (KF96-20cs of Shin-Etsu Chemical Co., Ltd.) to uniformly disperse it in a dispersion medium obtained to obtain an electrorheological fluid (9) of the present invention. It was

[0063]

Example 10 The additive dispersion (8) 25 obtained in Reference Example 12 instead of the additive dispersion (1) in Example 1
Silicon oil (K manufactured by Shin-Etsu Chemical Co., Ltd.)
An electrorheological fluid (10) of the present invention was obtained in the same manner as in Example 1 except that the amount of F96-20cs) used was changed to 45g.

[0064]

Comparative Example 1 30 g of dispersed phase particles (1) in Example 1
After drying at 150 ℃ for 3 hours, the temperature is 20 ℃, relative humidity 60
% Silicone oil (KF96-2 manufactured by Shin-Etsu Chemical Co., Ltd.)
(0 cs) mixed and dispersed in 70 g, and electrorheological fluid for comparison {hereinafter, this is referred to as comparative fluid (1). } Was obtained.

[0065]

Comparative Example 2 30 g of dispersed phase particles (1) in Example 1
After drying at 150 ℃ for 3 hours, the temperature is 20 ℃, relative humidity 60
% Chamber for 30 minutes to absorb moisture, and then use 10 cs of silicone oil (KF96-1 manufactured by Shin-Etsu Chemical Co., Ltd.)
(0 cs) mixed and dispersed in 70 g, and electrorheological fluid for comparison {hereinafter, this is referred to as comparative fluid (2). } Was obtained.

[0066]

Comparative Example 3 Instead of the additive dispersion liquid (1) in Example 1, the comparative additive dispersion liquid (1) 15 obtained in Reference Example 8 was used.
An electrorheological fluid for comparison {hereinafter, referred to as a comparative fluid (3)) by the same method as in Example 1 except that g was used. } Was obtained.

[0067]

Comparative Example 4 Comparative additive dispersion (2) 15 obtained in Reference Example 9 instead of additive dispersion (1) in Example 1
An electrorheological fluid for comparison {hereinafter, referred to as a comparative fluid (4)) by the same method as in Example 1 except that g was used. } Was obtained.

[0068]

COMPARATIVE EXAMPLE 5 3 g of the comparative additive (3) obtained in Reference Example 10 was used in place of the additive dispersion (1) in Example 1, and the amount of silicone oil used was 67 g. By the same method as in Example 1, an electrorheological fluid for comparison {this is referred to as a comparison fluid (5). } Was obtained.

[0069]

COMPARATIVE EXAMPLE 6 3 g of the comparative additive (4) obtained in Reference Example 11 was used in place of the additive dispersion (1) in Example 1, and the amount of silicone oil used was 67 g. By the same method as in Example 1, an electrorheological fluid for comparison {this is referred to as a comparative fluid (6). } Was obtained.

[0070]

Comparative Example 7 Instead of the additive dispersion liquid (1) in Example 1, an amino-modified silicone (KF8 manufactured by Shin-Etsu Chemical Co., Ltd.) which is a commercially available silicon-based additive having a nitrogen atom is used.
005) Use 10g and use 6g of silicone oil
An electrorheological fluid for comparison (this is referred to as a comparative fluid (7)) by the same method as in Example 1 except that the amount was 0 g. } Was obtained.

[0071]

Comparative Example 8 30 g of dispersed phase particles (2) in Example 8
After drying at 150 ℃ for 3 hours, the temperature is 20 ℃, relative humidity 60
% Chamber of 20% to absorb moisture, and then 20 cs of silicone oil (KF96-2 manufactured by Shin-Etsu Chemical Co., Ltd.)
(0 cs) mixed and dispersed in 70 g, and electrorheological fluid for comparison {hereinafter, this is referred to as comparative fluid (8). } Was obtained.

[0072]

Comparative Example 9 32 g of dispersed phase particles (3) in Example 9
After drying at 150 ℃ for 3 hours, the temperature is 20 ℃, relative humidity 60
% Silicone oil (KF96-2 manufactured by Shin-Etsu Chemical Co., Ltd.)
(0 cs) mixed and dispersed in 68 g, and electrorheological fluid for comparison {hereinafter, this is referred to as comparative fluid (9). } Was obtained.

[0073]

Example 11 At 23 ° C., the electrorheological fluids (1) to (10) and the comparative fluids (1) to (9) of the present invention obtained in Examples 1 to 10 and Comparative Examples 1 to 9 were used. The viscosity when no electric field was applied was measured. Then, each electrorheological fluid was placed on the bottom of a test tube having a height of 150 mm and a diameter of 15 mm.
It was filled up to 00 mm and sealed. After that, the sedimentation velocity of the dispersed phase particles was traced at room temperature, and the time (unit: day) required for the dispersed phase particles to settle 5 mm from the liquid surface of the electrorheological fluid filled in the test tube was measured to determine the dispersion stability. Was evaluated. Furthermore, 100 ml of 50 ml of each electrorheological fluid
Put it in a container and seal tightly, and leave it for one month, then 30 minutes per minute with the container.
The redispersibility was evaluated by rotating at the speed of rotation and measuring the total number of rotations required to return to the original uniform state. The results are shown in Table 1. Also, each of the electrorheological fluids was put into a double cylindrical rotary viscometer with a coaxial electric field, and the inner / outer tube gap was 1.0 mm,
The shear stress value (initial value) when an AC external electric field of 4000 V / mm (frequency: 50 Hz) was applied and the current density (initial value) flowing at that time were measured under conditions of a shear rate of 400 s- ¹ and a temperature of 25 ° C. Furthermore, 4000 V / mm
Stability of the electrorheological fluid was measured by measuring the shear stress value (value after 3 days) and current density (value after 3 days) after continuously operating the viscometer at 25 ° C for 3 days with the external electric field applied. I investigated the sex. The results are shown in Table 1.

[0074]

[Table 1]

As is clear from Table 1, the electrorheological fluids (1) to (10) of the present invention generate large shear stress even when a relatively weak electric field is applied, and the current density flowing at that time is large. It was excellent in current characteristics that it was small, and was excellent in stability of generated shear stress and current density with time. Further, it was excellent in dispersion stability and redispersibility in addition to low viscosity in a state where no electric field was applied.

The electrorheological fluids (1), (3) to (7) and (10) were the same dispersion phase and comparative fluid (1) containing the same dispersion medium and no additives, and the silicone-based polymerizable monomer. Comparative fluid (3) using the copolymer (8) lacking the monomer (A) as an additive, comparison using the copolymer (9) lacking the polymerizable monomer (B) as an additive It was found that the dispersion stability and redispersibility were significantly superior to those of the fluid (4) and the comparative fluid (5) and the comparative fluid (6) using the copolymerized fine particles of styrene and divinylbenzene. Further, compared with the comparative fluid (7) using the amino-modified silicone as an additive, which has poor current characteristics and redispersibility, the electrorheological fluids (1), (3) to (7) and (10) of the present invention have It was found that the current characteristics were excellent and the dispersion stability and redispersibility were also improved.

It was found that the electrorheological fluid (2) was much superior in dispersion stability and redispersibility to the comparative fluid (2) which used the same dispersed phase and dispersion medium but no additive. Further, the electrorheological fluid (8) was superior to the comparative fluid (8), and the electrorheological fluid (9) was superior to the comparative fluid (9) in both dispersion stability and redispersibility.

[0078]

INDUSTRIAL APPLICABILITY The electrorheological fluid of the present invention generates a large shear stress even when a relatively weak electric field is applied, and the current density flowing at that time is small. Excellent density stability over time, low initial viscosity when no electric field is applied, and dispersion stability (the ability to maintain electrorheological fluid in a uniform state for a long time without causing the dispersed phase to settle or float) and It is especially excellent in redispersibility (the ability to reproduce the original uniform state with a simple external force after the dispersed phase has settled or floated and becomes non-uniform), so engine mounts, clutches, dampers, brakes, It can be effectively used for shock absorbers, actuators, valves, etc.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08L 33/20 LJS 7921-4J 71/02 LQE 9167-4J C10M 169/04 9159-4H // ( C08L 25/18 83:10) (C10M 169/04 107: 50 9159-4H 155: 02 151: 02) C10N 20:06 Z 8217-4H 30:02 30:04 40:14 (72) Inventor Minoru Kobayashi 12-25 Kannondai, Tsukuba-shi, Ibaraki 12 Stock Company, Nippon Shokubai Tsukuba Research Center

Claims (3)

[Claims] 1. An electrorheological fluid containing a disperse phase composed of dielectric particles having an average particle size of 1 to 50 μm, a dispersion medium composed of a silicon-based insulating liquid, and an additive, which is generally used as the additive. A structural unit (a) represented by the formula-(SiR ¹ R ² O)-(wherein R ¹ and R ² are each independently an alkyl group or an aryl group) and / or the general formula (R ³ ₃ SiO) ₃ Si- (wherein R ³ is an alkyl group or an aryl group) is a silicon-based polymerizable having a structural unit (b) as a main constituent unit and an average molecular weight of 400 or more. Monomer (A) 3 to 70% by weight, general formula — (R ⁴ —O) n — (In the formula, R ⁴ is an alkylene group having 2 to ⁴ carbon atoms, and n is a number of 4 or more. .) represented by the structural unit (c) and / or the general formula - (CH ₂ -C ⁵ X) - (provided that wherein R ⁵ is hydrogen or methyl, X is -
CN or -COOR ^6, R ⁶ is an alkyl group having 1 to 4 carbon atoms. ) 0.5 to 40% by weight of a polymerizable monomer (B) having a structural unit (d) represented by the formula (b) as a main constituent unit and an average molecular weight of 400 or more, and other polymerizable monomers (C). ) 0 to 90% by weight (however, the total of the monomers (A), (B) and (C) is 100% by weight) A copolymer (I) obtained by polymerizing a monomer component. ) Is used in the range of 0.1 to 30 parts by weight with respect to 100 parts by weight of the dispersed phase. 2. The electrorheological fluid according to claim 1, wherein the copolymer (I) is obtained by polymerization in an alcohol solvent. 3. The dielectric particles as a dispersed phase are polystyrene polymer particles containing a sulfonic acid group.
The electrorheological fluid according to.