JP3307743B2 - Manufacturing method of electrorheological fluid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrorheological fluid. More specifically, a large shear stress is generated even by applying a relatively weak electric field, and the current density flowing at that time is excellent in current characteristics that it is small,
Excellent stability over time of generated shear stress and current density, and dispersion stability in the state where no electric field is applied (the ability to maintain the electrorheological fluid uniformly for a long time without causing the dispersed phase to settle or float), Redispersibility (the ability to reproduce the original uniform state with a simple external force after the dispersed phase settles or floats and becomes non-uniform) and fluidity (the ability to have a low viscosity when no electric field is applied) And a method for producing an electrorheological fluid which is particularly excellent.

[0002]

2. Description of the Related Art As an electrorheological fluid which generates a high shear stress, for example, a powder of an ion exchange resin suspended in a higher alkyl ester of an aromatic carboxylic acid (Japanese Patent Laid-Open No. 50-92278) has three types. A composition consisting of a crystalline substance that conducts current along only one of the crystal axes, a dielectric liquid and a steric stabilizer (Japanese Patent Laid-Open No. 1-170693), or a conductive particle covered with an electrically insulating thin film is used. Those used as a dispersed phase (JP-A-64-6096) have been proposed.
However, these electrorheological fluids are inferior in dispersion stability when no electric field is applied, redispersibility once settled or floated, and become poor in fluidity when the concentration of the dispersed phase is increased. Had problems.

In order to improve dispersion stability, a modified polysiloxane is used as an additive (Japanese Patent Publication No. 3-3956).
0), and those using a polymer containing an ester group structure and an aromatic group structure (JP-A-4-96997). However, these additives have a problem that even if the sedimentation speed of the dispersed phase can be suppressed, redispersibility after sedimentation is reduced.

Further, an electrorheological fluid using fine particles as an additive for improving redispersibility (Japanese Patent Laid-Open No. 3-16009)
4, JP-A-3-166295) has been proposed. However, in these electrorheological fluids, the shear stress value obtained when an electric field is applied is reduced by adding fine particles, or the use conditions of the electrorheological fluid are limited due to poor dispersion stability, There were problems such as the necessity of a redistribution mechanism in the device.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of a conventional electrorheological fluid.

Accordingly, an object of the present invention is to generate a large shear stress even by applying a relatively weak electric field,
It has excellent current characteristics that the current density flowing at that time is small, excellent in the stability of generated shear stress and current density over time, and dispersion stability in the state where no electric field is applied (without causing the dispersed phase to settle or float). The ability to maintain the electrorheological fluid uniformly for a long time), the redispersibility (the ability to reproduce the original uniform state with a simple external force after the dispersed phase settles or floats and becomes non-uniform), and the fluidity ( It is an object of the present invention to provide a method for producing an electrorheological fluid which is particularly excellent in the case where the viscosity is low when no electric field is applied.

[0007]

Means for Solving the Problems The present invention, the dispersed phase consisting of dielectric particles, a dispersion medium made of an insulating liquid, additive
Existing under the, a method of mixing the dispersion to that electrorheological fluids, the additive is a polysiloxane-containing polymer (II)
Generating a substantially insoluble particles (I) of a present in the insulating liquid
Particles (I) to be dissolved or substantially insoluble in an insulating liquid
By forming the polymer (II) in the presence of
Tsu and a composite that is obtained, the polymer (II) is the general formula (1)

[0008]

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[0009] (wherein Shikichu, A is shows a -COO- or phenylene group, R ¹ represents a hydrogen atom or a methyl group, R ²
Is an alkylene group having 1 to 6 carbon atoms, and R ^{3 to} R ¹³ are the same or different and represent an aryl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, respectively.
Is an arbitrary integer, b and c are the same or different, and
An integer of 10 and d represent an integer of 0 to 200, respectively. A) a polysiloxane-containing structural unit represented by formula (A)
And the general formula (2)

[0010]

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(Wherein, B represents —COO— or a phenylene group, R ¹⁴ represents a hydrogen atom or a methyl group,
¹⁵ is an alkylene group having 2 to 4 carbon atoms, R ¹⁶ is a hydrogen atom or an alkyl group, e is an arbitrary integer, and f is 2 to 100.
Indicates an integer. A) an alkylene oxide chain-containing structural unit (B-1) represented by the following general formula (3):

[0012]

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The nitrogen-containing atomic chain-containing structural unit (B)
-2) and general formula (4)

[0014]

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(Wherein, E represents —COO— or a phenylene group; R ¹⁹ represents a hydrogen atom or a methyl group;
²⁰ represents an alkyl group having 4 to 30 carbon atoms, and i represents an arbitrary integer. ) A hydrocarbon chain-containing structural unit (B-3)
Having at least one disperse phase-adsorbing chain-containing structural unit selected from the group consisting of (B) a manufacturing method of an electro-rheological fluid according to claim.

[0016]

The average particle diameter of the dielectric particles serving as the dispersed phase particles of the electrorheological fluid of the present invention is preferably in the range of 1 to 50 μm. When the average particle size of the dispersed phase is less than 1 μm, it is difficult to obtain a large shear stress when an electric field is applied to the prepared electrorheological fluid. When the average particle diameter of the dielectric particles exceeds 50 μm, it becomes difficult to obtain an electrorheological fluid having excellent dispersion stability in a state where no electric field is applied.

The dielectric particles serving as the dispersed phase particles of the electrorheological fluid of the present invention are not particularly limited as long as they are particles that are polarized under the application of an electric field, and are, for example, starch, cellulose, ion exchange resin, sulfonic acid group, and the like. Organic particles having a hydrophilic group such as polystyrene-containing polymer particles; hydrophilic inorganic particles such as silica, alumina, and zeolite; a conductive thin film layer formed on the surface of organic solid particles, and an electrically insulating thin film Conductive particles such as carbon black are dispersed in a particle having a three-layer structure in which a layer is formed, particles in which a thin film insulating layer is formed on the surface of conductive particles such as aluminum, particles using carbonaceous powder, and resin. Composite semiconductor particles such as poly (acene-quinone); ferroelectric particles such as barium titanate and lithium tartrate; That. Among the above-mentioned dielectric particles, the shear stress value obtained when an electric field is applied is large, and the current density flowing at that time is small and the stability over time is excellent, so that the sulfonic acid group-containing polystyrene-based polymer particles Use is preferred.

As a dispersion medium of the electrorheological fluid of the present invention,
There is no particular limitation as long as it is an electrically insulating oil. For example, silicone oils such as polydimethylsiloxane, partially octyl-substituted polydimethylsiloxane, and partially phenyl-substituted polydimethylsiloxane; liquid paraffin, decane, methylnaphthalene, decalin, diphenylmethane, partially hydrogenated Hydrocarbons such as triphenyl, etc .; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, bromobenzene, chlorobiphenyl, chlorodiphenylmethane, etc .; Fluoride; ester compounds such as dioctyl phthalate, trioctyl trimellitate, and dibutyl sebacate; and the like, and one or more of these can be used. Considering the viscosity of the prepared electrorheological fluid in a state where no electric field is applied, the viscosity of the dispersion medium is preferably 500 cP or less, particularly preferably 100 cP or less.

The present inventors have found that the dispersion stability, redispersibility and fluidity of an electrorheological fluid can be improved by controlling the state of a dispersed phase in a dispersion medium using a specific additive. And arrived at the present invention.

The additive used in the electrorheological fluid of the present invention comprises a particle (I) substantially insoluble in an insulating liquid, the above-mentioned polysiloxane-containing structural unit (A) and a structural unit containing a dispersed phase-adsorbing chain. It is necessary that the complex be a composite of the polysiloxane-containing polymer (II) having (B). However, the structural unit (B) comprises the above-described structural unit containing an alkylene oxide chain (B-1), the structural unit containing a nitrogen-containing atom chain (B-2), and the structural unit containing a hydrocarbon chain (B-3). At least one selected from the group can be selected, through this complex, an appropriate interaction occurs between the dispersed phase particles and the dispersion medium, and dispersion stability, redispersibility and fluidity in the electrorheological fluid Properties can be imparted.

Since the composite used in the present invention has a particle (I) portion that is substantially insoluble in the insulating liquid, the composite is also substantially insoluble in the insulating liquid. By being substantially insoluble in the dispersion medium, it is possible to prevent the particles of the dispersed phase from contacting each other in the electrorheological fluid, and to impart good redispersibility and fluidity to the electrorheological fluid. When the composite is substantially soluble in the insulating liquid, there arises a problem that redispersibility and fluidity cannot be imparted to the obtained electrorheological fluid.

In the present invention, the polysiloxane-containing polymer (I
The particles (I) which are substantially insoluble in the insulating liquid and which are combined with the insulating liquid (I) are not particularly limited as long as they are substantially insoluble in the insulating liquid. For example, polystyrene, poly (meth) acrylate, polyacrylonitrile, phenol resin , Benzoguanamine resin, melamine resin and other organic particles; silica,
Inorganic or inorganic particles such as alumina; organic or inorganic particles having a condensation or addition reactive group such as a hydroxyl group, amino group, carboxyl group, epoxy group or isocyanate group introduced into these organic or inorganic particles; styryl group or (meth) acryloyl Organic or inorganic particles into which a polymerization reactive group such as a group has been introduced.

The composite used in the present invention must have a polysiloxane-containing polymer (II) portion having a polysiloxane-containing structural unit (A) and a structural unit (B) containing a disperse phase-adsorbing chain as essential components. There is. The polysiloxane-containing structural unit (A) in the composite can cause an appropriate interaction between the composite and the dispersion medium to impart dispersion stability and fluidity to the electrorheological fluid. When there is no polysiloxane-containing structural unit (A), there arises a problem that the dispersion stability and fluidity of the electrorheological fluid decrease. In addition, the structural unit (B) containing the dispersed phase-adsorbing chain in the composite can cause an appropriate interaction between the composite and the dispersed phase particles to impart dispersion stability to the electrorheological fluid. . Structural unit containing dispersed phase adsorptive chains (B)
In the case where the electro-rheological fluid is not provided, there is a problem that the dispersion stability of the electrorheological fluid is reduced. The ratio of the polysiloxane-containing polymer (II) to the particles (I) substantially insoluble in the insulating liquid in the composite is in the range of 1 part by weight to 100 parts by weight with respect to 100 parts by weight of the former. Is preferred. If the ratio of the latter is less than 1 part by weight, dispersion stability may not be imparted to the electrorheological fluid. When the ratio of the latter exceeds 100 parts by weight, redispersibility and fluidity may not be imparted to the electrorheological fluid.

The composite is composed of the particles (I) substantially insoluble in the insulating liquid and the polysiloxane-containing polymer (II), but the form of the composite is not particularly limited. However,
Complex, it is not preferable in which the polymer (II) is conjugated to the surface of the particle (I).

The composite is preferably a composite of particles (I) substantially insoluble in an insulating liquid and a polysiloxane-containing polymer (II) via a chemical bond. By compounding via chemical bonds and the polymer particles (I) (II), Ru complexes can be easily obtained as a suitable additive to the present invention.

In the present invention, there is no particular limitation on the method of compounding the particles (I) substantially insoluble in the insulating liquid with the polysiloxane-containing polymer (II), and the particles (I) are present in the presence of the polymer (II). ), And simultaneously synthesizing and conjugating the particles (I), the method of producing the polymer (I) in the presence of the particles (I).
I) to generate, etc. Polymer synthesis and methods who performed composite of simultaneously (II) can be employed. When the complexing method of (1) is adopted, the complex of the present invention is obtained, for example, by polymerizing the -1 monomer mixture (X) to obtain a polysiloxane-containing polymer (II), and then obtaining the resulting polymer (II). ) Is polymerized in the presence of the polymerizable monomer (α) which gives particles (I) substantially insoluble in silicon-based insulating oil, and the polymerizable monomer (α) is dissolved to form a polymer ( A method of performing dispersion polymerization in a solvent that does not dissolve the particles (I)), a method of polymerizing the -2 monomer mixture (X) to obtain a polysiloxane-containing polymer (II), and then obtaining the obtained polymer (II). A) a method of emulsion-polymerizing a polymerizable monomer (α) which gives particles (I) substantially insoluble in an insulating liquid by polymerization in the presence of a) monomer mixture in an aqueous solvent; X) to give a polysiloxane-containing polymer (II), and then the resulting polymer (I)
A method of performing solution polymerization of the polymerizable monomer (α) in a solvent in which the polymerizable monomer (α) and the resulting polymer (particles (I)) are also dissolved in the presence of I). Are synthesized by Among these, the methods of -1 and -2 are preferable because a complex in which the polymer (II) is complexed on the surface of the particle (I) can be easily obtained with good reproducibility.
Further, among the methods of -1, the use of a polymer (II) having an ethylenically unsaturated group introduced as the polymer (II) allows the polymer (II) to be complexed to the surface of the particle (I) via a chemical bond. This is particularly preferable because the obtained complex can be easily obtained with good reproducibility.

When the compounding method of the present invention is adopted, the composite of the present invention uses, for example, the above-mentioned organic or inorganic fine particles as particles (I) substantially insoluble in silicon-based insulating oil. The monomer mixture (X) is polymerized in the presence of the fine particles to produce a polysiloxane-containing polymer (II)
Using the organic or inorganic fine particles having the condensation or addition reactive group introduced therein as the particles (I) substantially insoluble in the silicon-based insulating oil, in the presence of the organic or inorganic fine particles. And polymerizing the monomer mixture (X) to produce a polymer (II). -3 Particles (I) using the above-mentioned organic or inorganic fine particles into which the polymerization reactive group is introduced, and polymerizing the monomer mixture (X) in the presence of the organic or inorganic fine particles to obtain a polymer (II) Are synthesized by using a method for generating the Among these, the methods of -2 and -3 are preferable because a complex in which the polymer (II) is complexed to the surface of the particle (I) via a chemical bond is obtained. Further -3
The use of the above method is particularly preferable because a complex in which the polymer (II) is complexed to the surface of the particle (I) via a chemical bond can be easily obtained with good reproducibility.

[0028]

The process of synthesizing the complex by the method of -1 is described below.

The polysiloxane-containing polymer (II) has the general formula (5)

[0031]

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(Wherein F represents —COO— or a phenylene group; R ²¹ represents a hydrogen atom or a methyl group;
²² is an alkylene group having 1 to 6 carbon atoms, R ^{23 to} R ³³ are the same or different and represent an aryl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 10 carbon atoms,
j and k are the same or different and are each an integer of 0 to 10;
Represents an integer of 0 to 200, respectively. ), A silicon-based macromer (am) represented by the general formula (6)

[0033]

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(Wherein, G represents —COO— or a phenylene group; R ³⁴ represents a hydrogen atom or a methyl group;
³⁵ represents an alkylene group having 2 to 4 carbon atoms, R ³⁶ represents a hydrogen atom or an alkyl group, and m represents an integer of 2 to 100. ))-Containing macromer (bm-
1), general formula (7)

[0035]

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A monomer containing a nitrogen-containing atom chain (b-
2) and general formula (8)

[0037]

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(Where K represents —COO— or a phenylene group, R ³⁹ represents a hydrogen atom or a methyl group,
⁴⁰ represents an alkyl group having 4 to 30 carbon atoms. ), At least one kind of monomer (b) having a dispersed phase adsorptive chain selected from the long-chain hydrocarbon chain-containing monomers (b-3) represented by It is obtained by polymerizing the monomer mixture (X) containing the monomer (d).

The proportion of the silicon monomer (am) in the monomer mixture (X) is preferably in the range of 10 to 90% by weight, particularly preferably in the range of 20 to 80% by weight. preferable. When the ratio of the silicon monomer (am) is 10
If the content is less than 90% by weight or less than 90% by weight, dispersion stability and fluidity may not be imparted to the electrorheological fluid. Also,
The proportion of the monomer (b) containing a dispersed phase adsorptive chain in the monomer (X) is preferably in the range of 10 to 90% by weight, particularly preferably in the range of 20 to 80% by weight. preferable. When the ratio of the specific monomer (b) is less than 10% by weight or 9%
If the amount exceeds 0% by weight, sufficient dispersion stability of the electrorheological fluid may not be obtained.

When the method of -1 is adopted, the silicon-based macromer (am) used in the monomer mixture (X)
Examples of (meth) acryloyl group-containing polydimethylsiloxane, styryl group-containing polydimethylsiloxane, (meth) acryloyl group-containing partially octyl-substituted polydimethylsiloxane, styryl group-containing partially octyl-substituted polydimethylsiloxane, (meth) ) Acryloyl group-containing partially phenyl-substituted polydimethylsiloxanes,
Examples thereof include styryl group-containing partially phenyl-substituted polydimethylsiloxane, tris (trimethylsiloxy) silylpropyl (meth) acrylate, and the like, and one or more of these can be used.

Examples of the alkylene oxide chain-containing monomer (b-1) used as the dispersed phase adsorptive macromer (bm) include, 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 Polyalkylene glycols having a double bond, such as -isopropenylbenzyl group-containing polytetramethylene glycol, and the like. It can be used on.

The nitrogen-containing atom chain-containing monomer (b-2) includes a monomer containing one or more basic nitrogen atoms and an ethylenically unsaturated bond in one molecule, Examples include a nitrogen-containing derivative of (meth) acrylic acid, (meth) acrylonitrile, and an unsaturated monomer having a nitrogen-containing heterocycle.

The nitrogen-containing derivatives of (meth) acrylic acid include those having a substituted or unsubstituted amino group in the ester portion of (meth) acrylic acid ester and amides of (meth) acrylic acid. Aminoalkyl acrylate and (meth) acrylamide are preferably used. Examples of aminoalkyl (meth) acrylates include dimethylaminoethyl N, N- (meth) acrylate, diethylaminoethyl N, N- (meth) acrylate, dimethylaminopropyl N, N- (meth) acrylate, Examples thereof include dimethylaminobutyl N, N- (meth) acrylate. Examples of (meth) acrylamide include (meth) acrylamide, N- (meth) acrylamide, N-ethyl (meth) acrylamide, N
-Butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dimethylpropylacrylamide, etc., and one or more of these are used. be able to. Among these nitrogen-containing (meth) acrylic acid derivatives, those having a tertiary nitrogen atom are particularly preferred.

As the unsaturated monomer having a nitrogen-containing heterocyclic ring, a monocyclic or polycyclic heterocyclic ring containing 1 to 3, preferably 1 or 2 ring nitrogen atoms is bonded to a vinyl group. Monomers such as 1-vinyl-2-pyrrolidone,
Vinylpyrrolidones such as 1-vinyl-3-pyrrolidone;
Vinylpyridines such as 2-vinylpyridine, 4-vinylpyridine and 5-methyl-2-vinylpyridine; vinylimidazoles such as 1-vinylimidazole and 1-vinyl-2-methylimidazole; N- (meth) acryloylmorpholine And N- (meth) acryloylpyridine, and one or more of these can be used.

Examples of the long-chain hydrocarbon chain-containing monomer (b-3) include butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, and (meth) acrylic acid-2. -Ethylhexyl, dodecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, 2-methylstearyl (meth) acrylate, eicosyl (meth) acrylate, (meth)
(Meth) acrylates such as hexacosyl acrylate; long-chain alkyl-substituted styrenes such as butyl styrene, octyl styrene, dodecyl styrene, and stearyl styrene; one or more of these may be used; be able to.

Other monomers (d) include, for example, olefins such as ethylene, propylene and cyclohexene; alkyldienes such as butadiene, isoprene and cyclopentadiene; vinyl fluoride, vinylidene fluoride,
Halogenated olefins such as vinyl chloride and vinylidene chloride; aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, vinylnaphthalene, vinylanthracene, chlorostyrene and chloromethylstyrene; methyl (meth) acrylate And (meth) acrylates such as ethyl (meth) acrylate; methoxybutyl (meth) acrylate and alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate; (meth) acrylic acid- 2-hydroxyethyl,
Hydroxyalkyl esters of (meth) acrylic acid such as hydroxybutyl (meth) acrylate; esters of aromatic alcohols such as benzyl (meth) acrylate with (meth) acrylic acid; glycidyl (meth) acrylate or ( Hydroxyalkyl esters of (meth) acrylic acid and acetic acid, propionic acid, lauric acid, linoleic acid, p-
adduct with a monocarboxylic acid compound having 2 to 18 carbon atoms such as tert-benzoic acid; "Biscoat 8F" or "Biscoat 8FM" (trade name, manufactured by Osaka Organic Chemical Co., Ltd., (meth) acrylates having a fluorine atom) ), Fluorine-containing compounds such as perfluorocyclohexyl (meth) acrylate and perfluorocyclohexylethylene; vinyl acetate,
Vinyl esters such as vinyl benzoate; vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2-sulfoethyl (meth) acrylate, 3-sulfopropyl (meth) acrylate and the like Polymerizable unsaturated group-containing carboxylic acids such as sulfonic acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid and / or their sodium, calcium and ammonium salts And pyridinium salts and the like.

In the method (1), an electrorheological fluid is prepared by using a silicon-based insulating oil, which is a substantially electrically insulating fluid containing silicon oil as a main component, as a dispersion medium, and the resulting composite is added. It is preferably used as an agent. By using the composite in the silicon-based insulating oil, an electrorheological fluid having particularly excellent fluidity can be obtained.

Further, as the monomer (b) having a dispersed phase adsorptive chain in the monomer mixture (Y) serving as a raw material component of the polysiloxane-containing polymer (II), a long-chain hydrocarbon-containing monomer (B) b
-3) is preferably used in a proportion of 10 to 90% by weight, particularly preferably in a proportion of 20 to 80% by weight. When the amount of the long-chain hydrocarbon-containing monomer (b-3) is less than 10% by weight or more than 90% by weight, an electrorheological fluid having excellent dispersion stability, redispersibility and fluidity cannot be obtained with good reproducibility. Problems can occur.

As the polymerization method for obtaining the polysiloxane-containing polymer (II), a known polymerization method may be adopted, and for example, it can be obtained by a solution polymerization method using a radical generating catalyst.

As the radical-generating catalyst, any of those usually used for polymerization of vinyl monomers can be used. Representative examples include azo compounds such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile); benzoyl peroxide, di-tert-butyl par Oxide, ter
Peroxide-based compounds such as t-butyl peroctoate and tert-butyl peroxy-2-ethylhexanoate, and the like, which are usually 0.2 to 10 parts by weight, preferably 100 to 100 parts by weight of the monomer, preferably Is used in the range of 0.5 to 5 parts by weight.

The polymerization temperature is usually about 60 to 100 ° C. for about 1 to 15 hours.

As the solvent, hexane, heptane,
Aliphatic hydrocarbons such as octane; aromatic hydrocarbons such as benzene, toluene and xylene; alcohols such as isopropyl alcohol and butanol; ketones such as methyl isobutyl ketone and methyl ethyl ketone;
Esters such as isobutyl acetate, amyl acetate, and 2-ethylhexyl acetate; and cellsolves such as methylcellsolve and ethylcellsolve can be used.

After completion of the polymerization, the solution of the obtained polymer (II) can be used as it is for dispersion polymerization for synthesizing a complex as an additive, or the solvent is distilled off to obtain the polymer (II). ) Can be taken out and used.

The polymer (II) used in the method -1 is preferably reacted with a monomer having an ethylenically unsaturated group to introduce an ethylenically unsaturated group into the polymer (II). .

The polymer containing an ethylenically unsaturated group (I
By using (I), when the composite is synthesized, the polymerization product of the polymerizable monomer (α) and the polymer (II) are chemically bonded. And the dispersion stability after use under a high shear rate can be improved.

The introduction of an ethylenically unsaturated group into the polymer (II) is carried out, for example, by adding acrylic acid, methacrylic acid, maleic acid, vinyl sulfonic acid to one component of the monomer mixture during the synthesis of the polymer (II). For example, the reaction can be carried out by using an acid group-containing monomer such as glycidyl (meth) acrylate or allyl glycidyl ether.

The composite serving as an additive in the method of -1 is obtained by dispersion-polymerizing the polymerizable monomer (α) in the presence of the polymer (II).

The dispersion polymerization referred to in the method -1 is a polymerization carried out in an organic solvent in which a polymerizable monomer (α) is dissolved in the presence of a dispersion stabilizer but a polymer formed by polymerization is not dissolved. is there.

The organic solvent used in the dispersion polymerization of the method -1 does not substantially dissolve the complex formed by the polymerization, but it is not soluble in the polymer (II) and the polymerizable monomer (α). Is a good solvent.

Examples of such organic solvents include aliphatic hydrocarbons such as hexane, heptane and octane; aromatic hydrocarbons such as benzene, toluene and xylene; methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol and the like. Alcohols such as ether solvents such as cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, ethyl acetate, and isobutyl acetate, ketones, and esters, and one or more of these can be used as a mixture. .

The polymerizable monomer (α) polymerized in the method of -1 in the presence of the polymer (II) is not particularly limited as long as it is soluble in the above-mentioned organic solvent. Aromatic compounds such as vinyltoluene, p-chlorotoluene, and vinylpyridine; (meth) such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and benzyl (meth) acrylate
Acrylic esters and the like can be mentioned.

Dispersion polymerization for synthesizing a composite as an additive of the electrorheological fluid in the method of -1 is usually performed using a radical generating catalyst. Examples of the radical generating catalyst include 2,2′-azobisisobutyronitrile,
Azo compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile); peroxide compounds such as benzoyl peroxide and lauryl peroxide;
These are usually used in an amount of 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the polymerizable monomer (α).

In the method (1), in the dispersion polymerization for synthesizing the composite, the polymer (II) is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polymerizable monomer (α). Is preferably used, and more preferably used in the range of 1 to 6 parts by weight. If the amount of the polymer (II) used is less than 0.1 part by weight, the dispersion polymerization for synthesizing the complex cannot be performed stably, or even if it is obtained, the dispersion stability of the prepared electrorheological fluid is reduced. Sometimes it cannot be improved. If the amount of the polymer (II) exceeds 10 parts by weight, a problem that the redispersibility and fluidity of the prepared electrorheological fluid become poor tends to occur.

The total concentration of the polymerizable monomer (α) and the polymer (II) in the organic solvent is 5 to 50% by weight, preferably 10 to 30% by weight. Further, at the time of dispersion polymerization, a conventionally known dispersion stabilizer such as a surfactant or a polymer compound may be appropriately mixed and used in an organic solvent.

The dispersion polymerization at the time of synthesizing the complex in the method -1 may be performed by a known polymerization method.
The reaction is carried out at a temperature in the range of １００100 ° C. for 0.5 to 30 hours.

After completion of the polymerization, if necessary, treatment can be carried out by a known method such as solvent replacement, solvent evaporation, drying and pulverization. In particular, it is preferable to use the polymerization solvent after replacing the solvent with a silicon-based insulating oil because the workability in preparing the electrorheological fluid is improved.

The additive complex obtained by the method (1) is preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the dispersed phase. It is particularly preferred to use in the range. If the amount of the additive is less than 0.1 part by weight based on the dispersed phase, the dispersion stability and redispersibility of the electrorheological fluid may not be sufficiently improved. If the amount exceeds 10 parts by weight, dispersion stability corresponding to the added amount may not be obtained, or the fluidity of the electrorheological fluid may decrease.

The process of synthesizing the complex by the method of -2 is described below.

The composite used in the method (2) is obtained by emulsion polymerization of the polymerizable monomer (α) in a medium containing water as a main component in the presence of the polymer (II).

The polymerization reaction in an aqueous medium at the time of synthesizing the complex by the method of -2 is preferably performed using a water-soluble radical generating catalyst. As a radical generating catalyst,
It can be used without any particular limitation as long as it is used for emulsion polymerization of ordinary vinyl monomers, for example, sodium persulfate, potassium persulfate, ammonium persulfate,
4,4′-azobis-4-cyanovaleric acid, 2,
2′-azobis-aminodipropane hydrochloride and the like.

In the method (2), the polymer (II) is used in the range of 0.1 to 10 parts by weight per 100 parts by weight of the polymerizable monomer (α) in the polymerization reaction for synthesizing the complex. Is preferably used, and more preferably used in the range of 1 to 6 parts by weight. If the amount of the polymer (II) is less than 0.1 part by weight, the polymerization reaction for synthesizing the complex cannot be performed stably, or even if the complex is obtained, sufficient dispersion stability in the electrorheological fluid is obtained. May not be given. If the amount of the polymer (II) exceeds 10 parts by weight, the prepared electrorheological fluid may have poor redispersibility and fluidity.

The total concentration of the polymerizable monomer (α) and the polymer (II) in the aqueous medium is preferably from 5 to 50% by weight, more preferably from 10 to 30% by weight.

The emulsion polymerization for synthesizing the complex by the method of -2 can be carried out in an aqueous medium comprising water or a mixed solvent with an organic solvent containing water as a main component. As the organic solvent that can be used in the present invention, an organic solvent having a strong affinity for water, for example, methanol, ethanol,
There are alcohols such as isopropanol, cellsolves such as methylcellosolve and ethylcellosolve, and glycols such as ethylene glycol and diethylene glycol. When a mixed solvent is used, it is preferably used so that the polymerizable monomer (α) does not dissolve.

The polymerization reaction for synthesizing the complex in the method (2) is usually carried out in a temperature range of 50 to 100 ° C. for about 2 to 40 hours.

As the operation of the polymerization reaction, water and the polymer (II) are usually charged into a reaction vessel to make a uniform dispersion state under stirring, and a part or all of the polymerizable monomer (α) is optionally added. After the addition and heating to a predetermined temperature, a radical generating catalyst is added to start the reaction. Further, the remainder of the polymerizable monomer (α) is added, and polymerization is carried out at a predetermined temperature in an emulsified state. After the completion of the polymerization, if necessary, treatment can be performed by a known method such as solvent replacement, solvent evaporation, drying, and pulverization.

The process of synthesizing the complex by the method -3 will be described below.

As the particles (I) which are substantially insoluble in the insulating liquid used in the method (3), organic or inorganic fine particles into which a polymerization reactive group is introduced are used. The fine particles having a polymerization reactive group are, for example, compounds (e) having a functional group and a polymerizable reactive group capable of reacting with the above-mentioned functional group present on the surface of the organic or inorganic fine particles. For example.

Compound (e) having such two groups
Examples thereof include vinyl group-containing silane coupling agents such as γ- (meth) acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltrichlorosilane; glycidyl (meth) acrylate, allyl glycidyl ether And glycidyl group-containing unsaturated compounds.

The amount of the compound (e) for introducing a polymerization reactive group into the organic or inorganic fine particles is not particularly limited.
It is preferable to use within the range of 100 parts by weight.

In the case of obtaining the composite by the method of -3, the polymerization of the monomer mixture (Y) is carried out in the presence of an organic solvent in the presence of particles (I) comprising organic or inorganic fine particles into which a polymerization reactive group has been introduced. Preferred is a method in which the polymerization is carried out using a polymerization initiator.

Examples of the organic solvent include aliphatic hydrocarbons such as hexane, heptane and octane; aromatic hydrocarbons such as benzene, toluene and xylene; methyl alcohol;
Alcohols such as ethyl alcohol, isopropyl alcohol and n-butyl alcohol; ether-based, ketone-based and ester-based organic solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, ethyl acetate and isobutyl acetate; These can be used alone or in combination of two or more.

Examples of the polymerization initiator include peroxide initiators such as benzoyl peroxide and lauryl peroxide; 2,2′-azobisisobutyronitrile, 2,2 ′
And azo-based initiators such as -azobis (2,4'-dimethylvaleronitrile).

The polymerization is carried out at a temperature of 50 to 100 ° C., usually for 0.5 to 15 hours.

After completion of the polymerization, if necessary, treatment can be carried out by a known method such as solvent replacement, solvent evaporation, drying and pulverization.

The electrorheological fluid of the present invention is obtained by mixing and dispersing a dispersed phase composed of dielectric particles in a dispersion medium composed of an insulating liquid in the presence of the above-mentioned additives composed of various composites. Things.

The ratio of the dispersed phase to the dispersion medium in the electrorheological fluid of the present invention is such that the former is 100 parts by weight and the latter is 50 to 5 parts by weight.
It is preferably in the range of 00 parts by weight. If 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. In addition, when the amount of the dispersion medium is less than 50 parts by weight, the fluidity of the prepared composition itself is reduced, and it may be difficult to use the composition as an electrorheological fluid.

The electrorheological fluid of the present invention may contain, for example, known polymer dispersants, surfactants, polymer thickeners, fine particles and other additives for adjusting the viscosity or improving the shear stress. Conventionally known various additives can be added.

[0088]

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

Reference Example 1 150 g of toluene and azobisisobutyronitrile 1 were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
g, methacryloyl group-containing polydimethylsiloxane (Silaprene FM0721 manufactured by Chisso Corporation, average molecular weight = about 5000) as a silicon-based macromer (am) 5
Methacryloyl group-containing methoxypolyethylene glycol (NK ester M-230G manufactured by Shin-Nakamura Chemical Co., Ltd., degree of polymerization of polyethylene glycol n = about 23, average molecular weight = 0 g)
(About 1100), and stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 80 ° C. for 2 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polysiloxane-containing polymer (hereinafter, referred to as polymer) (1).
350 g of isopropyl alcohol, 2.5 g of polymer (1), 1.5 g of azobisisobutyronitrile and 1.5 g of polymerizable monomer were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. 50 g of styrene is added as a body (α), and the mixture is blown with nitrogen at room temperature for 30 minutes.
Stirred for minutes. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. 200 g of 20 cs silicon oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the reaction solution.
Is dropped under reduced pressure by an evaporator to distill off volatile components, and a silicone oil dispersion of the complex (1) (the content of the complex (1) is 20% by weight; hereinafter, an additive dispersion (1) )).

Reference Example 2 150 g of toluene and azobisisobutyronitrile 1 were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
g, methacryloyl group-containing polydimethylsiloxane (Silaprene FM0721 manufactured by Chisso Corporation, average molecular weight = about 5000) as a silicon-based macromer (am) 4
0 g and 60 g of dodecyl methacrylate were added as the monomer (b) having a dispersed phase adsorptive chain, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 75 ° C. for 3 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (2).

In a 500 ml four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 350 g of isopropyl alcohol, 2 g of polymer (2), 1 g of azobisisobutyronitrile, polymerizable monomer 50 g of styrene was added as (α), and the mixture was blown with nitrogen at room temperature.
Stirred for minutes. This was heated at 70 ° C. for 15 hours to carry out a polymerization reaction. 200 g of 20 cs silicon oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the reaction solution.
After dropping, the volatile component is distilled off by drying under reduced pressure using an evaporator, and the silicone oil dispersion of the composite (2) (the content of the composite (2) is 20% by weight, hereinafter referred to as the additive dispersion (2) )).

Reference Example 3 200 g of toluene, 1 g of benzoyl peroxide, and tris (trimethylsiloxy) as a silicon-based macromer (am) were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. ) Silylpropyl methacrylate (Shin-Etsu Chemical Co., Ltd.)
X-22-5002, average molecular weight = about 422) 70
g, 20 g of butyl acrylate as the dispersed phase adsorptive chain-containing monomer (b) and 10 g of styrene as the other monomer (d) were stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (3).

Hexane 3 was placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
50 g, 2.5 g of polymer (3), 1 g of azobisisobutyronitrile, 40 g of methyl methacrylate and 10 g of benzyl methacrylate as polymerizable monomer (α) were stirred at room temperature for 30 minutes while blowing nitrogen. 70 ℃
For 20 hours to carry out a polymerization reaction. 2
0cs silicone oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.)
6-20cs) After dropping 200 g, the volatiles are distilled off by drying under reduced pressure with an evaporator, and the silicone oil dispersion of the composite (3) (the content of the composite (3) is 20% by weight; Agent dispersion (3) was obtained.

Reference Example 4 200 g of toluene and azobisisobutyronitrile 3 were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
g, methacryloyl group-containing polydimethylsiloxane (Silaprene FM0721 manufactured by Chisso Corporation, average molecular weight = about 5000) as a silicon-based macromer (am) 5
Then, 0 g and 45 g of dodecyl methacrylate as the monomer (b) containing the dispersed phase adsorbing chain and 5 g of methacrylic acid as the other monomer (d) were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 80 ° C. for 2 hours to carry out a polymerization reaction. Furthermore, 5 g of glycidyl methacrylate
And 1 g of dimethylaminoethanol and add 100 ° C
For 5 hours. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (4).

In a 500 ml four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 350 g of isopropyl alcohol, 2 g of polymer (4), 2 g of azobisisobutyronitrile and polymerizable monomer 50 g of styrene was added as (α), and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. 20 cs of silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) 200 was added to the reaction solution.
g of the complex (4), the volatile matter was distilled off by drying under reduced pressure with an evaporator, and the silicone oil dispersion of the complex (4) (the content of the complex (4) was 20% by weight; 4)).

Reference Example 5 200 g of toluene and azobisisobutyronitrile 3 were placed in a 500 ml four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube.
g, methacryloyl group-containing polydimethylsiloxane (Silaprene FM0721 manufactured by Chisso Corporation, average molecular weight = about 5000) as a silicon-based macromer (am) 5
0 g and 50 g of diethylaminoethyl methacrylate were added as the monomer (b) having a dispersed phase adsorptive chain, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. 70 ℃
For 3 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (5).

In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 350 g of isopropyl alcohol, 2 g of polymer (5), 2 g of azobisisobutyronitrile and 2 g of polymerizable monomer 50 g of styrene was added as (α), and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. 20 cs of silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) 200 was added to the reaction solution.
g, the volatile matter was distilled off by drying under reduced pressure with an evaporator, and the silicone oil dispersion of the complex (5) (the content of the complex (5) was 20% by weight; 5)).

Reference Example 6 In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 400 g of tetrahydrofuran, and polydimethylsiloxane containing a methacryloyl group as a silicon-based macromer (am) (Nisso ( Co., Ltd.'s Silaplane FM072
1, average molecular weight = about 5000), 20 g of diethylaminoethyl methacrylate and 1 g of azobisisobutyronitrile as a monomer (b) containing a disperse phase-adsorbing chain, and 10% by weight of sodium styrenesulfonate are dissolved therein. 100 g of an ion exchange aqueous solution was mixed. After stirring at room temperature for 30 minutes while blowing nitrogen, the mixture was heated at 75 ° C. for 3 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain a polymer (6).

A 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube was charged with 200 g of ion-exchanged water, 2 g of the polymer (6) and 1 g of sodium persulfate. Here, 40 g of styrene as a polymerizable monomer (α) was added, and the mixture was stirred at 20,000 rpm for 2 minutes by a disperser while blowing nitrogen. This at 70 ° C
The mixture was heated for an hour and further heated at 90 ° C. for 3 hours to carry out a polymerization reaction. After the polymerization is completed, the dispersion medium is converted from water to isopropyl alcohol by azeotropic distillation, and 160 g of a mineral electric insulating oil (manufactured by Cosmo Oil Co., Ltd., high-pressure insulating oil) is further added. A mineral electric insulating oil dispersion of the additive (6) composed of a polystyrene-based composite (the content of the additive (6) was 20% by weight, hereinafter referred to as an additive dispersion (6)) was obtained.

Reference Example 7 In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 200 g of tetrahydrofuran and polydimethylsiloxane containing a methacryloyl group as a silicon-based macromer (am) (Nisso ( Co., Ltd.'s Silaplane FM072
1, average molecular weight = approximately 5000) 20 g, acrylonitrile 20 g as a monomer (b) containing a dispersed phase adsorptive chain, 5 g methacrylic acid and 5 g glycidyl methacrylate as other monomers (d), 1 g azobisisobutyronitrile Was dissolved therein and mixed with 150 g of a 10% by weight aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate in ion-exchange. After stirring at room temperature for 30 minutes while blowing nitrogen, the mixture was heated at 75 ° C. for 3 hours to carry out a polymerization reaction. After completion of the reaction, the volatile matter was distilled off by heating under reduced pressure with an evaporator to obtain a polymer (7).

A 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube was charged with 200 g of ion-exchanged water, 2 g of the polymer (7) and 1 g of sodium persulfate. 50 g of methyl methacrylate as a polymerizable monomer (α) was added thereto, and the mixture was stirred at 20,000 rpm for 2 minutes by a disperser while blowing nitrogen. This was heated at 70 ° C. for 3 hours and further heated at 90 ° C. for 3 hours to carry out a polymerization reaction. After the polymerization is completed, the dispersion medium is converted from water to isopropyl alcohol by azeotropic distillation, and then 160 g of a mineral electric insulating oil (high-pressure insulating oil manufactured by Cosmo Oil Co., Ltd.)
And the isopropyl alcohol is distilled off under reduced pressure. A mineral electric insulating oil dispersion of the additive (7) comprising a crosslinked poly (methyl methacrylate) composite microgel (the content of the additive (7) is 20% by weight; Agent dispersion (7)) was obtained.

Reference Example 8 A 300-ml flask was charged with 150 ml of methanol and 50 ml of ion-exchanged water, and 10 g of spherical silica particles (Nippon Shokubai Co., Ltd., true sphere, average particle diameter 1 μm) were dispersed. 5 g of γ- (methacryloxypropyl) trimethoxysilane was added thereto,
For 2 hours to introduce a methacryloyl group on the surface of the spherical silica particles. Thereafter, the solvent was distilled off under reduced pressure using an evaporator, and dried at 50 ° C. using a vacuum dryer to obtain a reaction product. Next, add 150m of toluene to a 200ml flask.
and 15 g of the obtained reaction product was dispersed. There, 0.1 g of azobisisobutyronitrile and methacryloyl group-containing polydimethylsiloxane (Silaprene FM manufactured by Chisso Corporation) as a silicon-based macromer (am)
0721, average molecular weight = about 5000) 0.75 g, and methacryloyl group-containing methoxypolyethylene glycol (NKS M-230G manufactured by Shin-Nakamura Chemical Co., Ltd., polyethylene glycol as a dispersed phase adsorptive chain-containing monomer (b)) Degree of polymerization n = about 23, average molecular weight = about 110
0) 0.75 g was dissolved and reacted at 70 ° C. for 5 hours. 66 g of 20 cs silicone oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to the reaction solution,
The volatiles were distilled off under reduced pressure using an evaporator to obtain a silicone oil dispersion of the complex (8) (content of the complex (8): 20% by weight, hereinafter referred to as an additive dispersion (8)).

Reference Example 9 A 300 ml flask was charged with 150 ml of methanol and 50 ml of ion-exchanged water, and 10 g of spherical silica particles (Nippon Shokubai Co., Ltd., true sphere, average particle diameter 1 μm) were dispersed. 5 g of γ- (methacryloxypropyl) trimethoxysilane was added thereto,
For 2 hours to introduce a methacryloyl group on the surface of the spherical silica particles. Thereafter, the solvent was distilled off under reduced pressure using an evaporator, and dried at 50 ° C. using a vacuum dryer to obtain a reaction product. Next, 150 ml of toluene was placed in a 200 ml flask.
And 15 g of the obtained reaction product was dispersed. There, 0.1 g of azobisisobutyronitrile and methacryloyl group-containing polydimethylsiloxane (silaplane FM0 manufactured by Chisso Corporation) as a silicon-based macromer (am)
721, average molecular weight = about 5000) and 0.9 g of dodecyl methacrylate as the dispersed phase adsorptive chain-containing monomer (b) were dissolved and reacted at 70 ° C. for 5 hours. 20 cs of silicone oil (Shin-Etsu Chemical Co., Ltd.)
After dropping 66 g of KF96-20cs (manufactured by Kabushiki Kaisha), the volatile components were distilled off under reduced pressure by an evaporator, and the silicone oil dispersion of the complex (9) (the content of the complex (9) was 20% by weight; (Referred to as (9)).

REFERENCE EXAMPLE 10 480 ml of water was charged into a 1-liter four-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, and charged with Kuraray Povar PVA-20.
5 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) 6.4 g
Is added and dissolved, and then methyl methacrylate 11 is further added.
0 g, industrial divinylbenzene (Wako Pure Chemical Industries, Ltd.)
55% by weight of divinylbenzene, ethylstyrene 35
A mixture consisting of 10 g of a mixture (weight% etc.) and 3 g of azobisisobutyronitrile was added. Thereafter, the contents in the flask were dispersed at a stirring speed of 20,000 rpm using a disperser, and polymerized at 70 ° C. for 8 hours. The obtained solid was separated by filtration, sufficiently washed with water, and then dried with a hot air drier.
Dried at 12 ° C. for 12 hours, and 115 g of spherical crosslinked polymer fine particles
I got

Next, the polymerized crosslinked fine particles 1 were placed in a 1-liter three-neck separable flask equipped with a stirrer and a thermometer.
Then, 400 g of a 10% by weight methanol solution of sodium hydroxide was added to obtain a uniform dispersion. After raising the temperature of the reaction mixture to 70 ° C., the mixture was heated at the same temperature for 24 hours.
The mixture was stirred to perform a saponification reaction. Thereafter, the reaction mixture was separated by filtration and washed with water. 500 ml of 2N hydrochloric acid
And then washed thoroughly with water. Then, it dried at 80 degreeC for 10 hours using the vacuum dryer, and obtained 95 g of carboxylic acid group-containing polymer particles with an average particle diameter of 2 micrometers insoluble in silicon-based insulating oil.

150 ml of toluene was placed in a 300 ml flask.
and then 10 g of the carboxylic acid group-containing polymer particles synthesized above were dispersed therein. 5 g of glycidyl methacrylate and 0.75 g of dimethylaminoethyl methacrylate were added thereto, and reacted at 40 ° C. for 5 hours to introduce methacryloyl groups on the surface of the polymer particles. Next, 0.1 g of azobisisobutyronitrile and methacryloyl group-containing polydimethylsiloxane (Silaprene FM072 manufactured by Chisso Corporation) as a silicon-based macromer (am)
0.75 g of 1, average molecular weight = about 5000) and 0.5 g of diethylaminoethyl methacrylate and 0.5 g of stearyl methacrylate as the dispersed phase adsorptive chain-containing monomer (b) were added and dissolved, and reacted at 70 ° C. for 5 hours. did. 68 g of 20 cs silicone oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to the reaction solution.
The volatiles were distilled off under reduced pressure using an evaporator to obtain a complex (10).
Silicone oil dispersion (composite (10) content 20
% By weight, hereinafter referred to as an additive dispersion (10)).

Reference Example 11 150 ml of toluene was charged into a 300 ml flask, and 10 g of the carboxylic acid group-containing polymer particles obtained in Reference Example 10 were dispersed therein. 5 g of glycidyl methacrylate and 0.75 g of dimethylaminoethyl methacrylate were added thereto, and reacted at 40 ° C. for 5 hours to introduce methacryloyl groups on the surface of the polymer particles. Next, 0.1 g of azobisisobutyronitrile and 0.75 methacryloyl group-containing polydimethylsiloxane (Silaprene FM0721 manufactured by Chisso Corporation, average molecular weight = about 5000) as a silicon-based macromer (am) 0.75
g, and 0.5 g of 1-vinyl-2-pyrrolidinone as a monomer (b) containing an adsorbent chain having a dispersed phase, and dissolved.
For 5 hours. 20 cs of silicone oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) 6 was added to the reaction solution.
After dropping 8 g, the volatile components were distilled off under reduced pressure by an evaporator, and the silicone oil dispersion of the complex (11) (the content of the complex (11) was 20% by weight;
1)).

Reference Example 12 150 ml of toluene was charged into a 300 ml flask, and 10 g of the carboxylic acid group-containing polymer particles synthesized above were dispersed therein. Thereto were added 5 g of glycidyl methacrylate and 0.75 g of dimethylaminoethyl methacrylate as the dispersed phase adsorptive chain-containing monomer (b), and reacted at 40 ° C. for 5 hours to form a methacryloyl group on the surface of the polymer particles. Introduced. Next, 0.1 g of azobisisobutyronitrile, 0.75 g of acrylonitrile as a monomer (b) containing a disperse phase-adsorbing chain, and methacryloyl group-containing polydimethylsiloxane (manufactured by Chisso Corp.) (Silaplane FM0721, average molecular weight = about 5000) 1.0
g was added and dissolved, and reacted at 70 ° C. for 5 hours. 68 g of an electric insulating oil (manufactured by Cosmo Oil Co., Ltd., high-pressure insulating oil) containing 10 cs of a mineral hydrocarbon as a main component was dropped into the reaction solution, and the volatile components were distilled off under reduced pressure by an evaporator to obtain a complex (1).
2) Electric insulating oil dispersion (content of composite (12): 20)
% By weight, hereinafter referred to as an additive dispersion (12)).

Reference Example 13 100 ml of toluene was placed in a 200 ml flask, and 0.5 g of azobisisobutyronitrile and a polydimethylsiloxane containing a methacryloyl group as a silicon-based macromer (am) (a sila manufactured by Chisso Corporation) were used. Plain FM0721, average molecular weight =
About 5000) 10 g, monomer having dispersed phase adsorbing chain (b)
As a methacryloyl group-containing methoxypolyethylene glycol (manufactured by Shin-Nakamura Chemical Co., Ltd.)
30G, degree of polymerization of polyethylene glycol n = about 23,
(Average molecular weight = about 1100) 30 g and dimethylaminoethyl methacrylate 10 g were dissolved and reacted at 70 ° C for 5 hours. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (8).

480 ml of water was placed in a 1-liter four-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer.
And 6.4 g of the above polymer (8) was added and dissolved, and then a mixture composed of 120 g of methyl methacrylate and 3 g of azobisisobutyronitrile was further added. Thereafter, the contents in the flask were dispersed at a stirring speed of 20,000 rpm using a disperser, and polymerized at 70 ° C. for 8 hours. After completion of the polymerization, the dispersion medium is converted from water to isopropyl alcohol by azeotropic distillation, and 488 g of an electric insulating oil (manufactured by Cosmo Oil Co., Ltd., high-pressure insulating oil) mainly composed of a mineral hydrocarbon of 10 cs is dropped. The volatile components were distilled off under reduced pressure using an evaporator to obtain an electrically insulating oil dispersion of the composite (13) (a content of the composite particles (13): 20% by weight, hereinafter referred to as an additive dispersion (13)).

Reference Example 14 200 g of ion-exchanged water, 2 g of sodium dodecylsulfonate and 1 g of sodium persulfate were dissolved in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. .
Here, 35 g of styrene and industrial divinylbenzene (manufactured by Wako Pure Chemical Industries, Ltd., 55% by weight of divinylbenzene,
15 g of a monomer component (a mixture of 35% by weight of ethylstyrene, etc.) was added, and emulsification was performed at 20,000 rpm for 2 minutes by a disperser while blowing nitrogen. This is 7
The polymerization reaction was performed by heating at 0 ° C. for 3 hours and further heating at 90 ° C. for 4 hours. Water was distilled off by heating the reaction solution under reduced pressure with an evaporator, and then dried overnight in an air oven at 80 ° C. to obtain crosslinked polymer particles (14) (hereinafter referred to as comparative additives (1)). Was.

Reference Example 15 350 g of isopropyl alcohol, 2.5 g of polyvinylpyrrolidone, 1 g of azobisisobutyronitrile and 1 g of styrene were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. 50 g was added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. To the reaction solution, 20 cs of silicone oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added.
After dropping 0 g, the volatile matter was distilled off by drying under reduced pressure with an evaporator, and a silicone oil dispersion of polystyrene particles (15) (polystyrene particles (15) content: 20% by weight; (It is called (2))
I got

REFERENCE EXAMPLE 16 100 ml of toluene was placed in a 200 ml flask, 2 g of azobisisobutyronitrile, and polydimethylsiloxane containing a methacryloyl group as a silicon-based macromer (am) (Silaprene FM0721 manufactured by Chisso Corporation, average Molecular weight = about 500
0) 35 g and a methacryloyl group-containing methoxypolyethylene glycol (NKS M-230 manufactured by Shin-Nakamura Chemical Co., Ltd.)
G, degree of polymerization of polyethylene glycol n = about 23, average molecular weight = about 1100) 35 g was dissolved and reacted at 70 ° C. for 5 hours. After completion of the reaction, the solvent was distilled off under reduced pressure using an evaporator to obtain a polymer. 20 cs silicone oil (KF96-2 manufactured by Shin-Etsu Chemical Co., Ltd.) in a 200 ml flask
0cs) 68 g, and spherical silica particles (Nippon Shokubai Co., Ltd., true sphere, average particle diameter 1 μm) 15
g of the polymer synthesized above, 2 g of the polymer synthesized above was added and dispersed, and a silicon oil dispersion (additive) of an additive (16) in which silica particles and the polymer were separately dispersed without being complexed. A content of (16) of 20% by weight, hereinafter referred to as a comparative additive dispersion (3)) was obtained.

Reference Example 17 A 300-ml flask was charged with 150 ml of methanol and 50 ml of ion-exchanged water, and 10 g of spherical silica particles (Nippon Shokubai Co., Ltd., true sphere, average particle diameter 1 μm) were dispersed. 5 g of γ- (methacryloxypropyl) trimethoxysilane was added thereto,
By reacting at 40 ° C. for 2 hours, methacryloyl groups were introduced on the surface of the spherical silica particles. Thereafter, the solvent was distilled off under reduced pressure using an evaporator, and dried at 50 ° C. using a vacuum dryer to obtain a reaction product. Next, toluene 1 was placed in a 200 ml flask.
50 ml was added, and 15 g of the obtained reaction product was dispersed. There, 0.1 g of azobisisobutyronitrile, 1.5 g of polydimethylsiloxane containing a methacryloyl group (Silaprene FM0721 manufactured by Chisso Corporation, average molecular weight = about 5000) as a silicon macromer (am)
Was dissolved and reacted at 70 ° C. for 5 hours. 10
After dropping 66 g of electric insulating oil (high-pressure insulating oil, manufactured by Cosmo Oil Co., Ltd.) mainly containing cs mineral hydrocarbon, volatile components were distilled off under reduced pressure using an evaporator to obtain an additive (1).
7) Electric insulating oil dispersion (content of additive (17): 20)
%, Hereinafter referred to as a comparative additive dispersion (4)).

Example 1 A 3-liter four-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer was charged with 1.2 liters of water, and was charged with Kuraray Povar PVA-2.
05 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) 24.0
g of styrene, 405 g of styrene, 45 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene, 35% by weight of ethylstyrene, etc., manufactured by Wako Pure Chemical Industries, Ltd.) and azobisisobutyro. Nitrile 12
g of the mixture was added. Then, the contents in the flask were dispersed at a stirring speed of 7000 rpm,
Polymerized for hours. The obtained solid was separated by filtration, sufficiently washed with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain 435 g of a spherical polymer crosslinked product (hereinafter referred to as a polymer crosslinked product (1)). I got

Then, 400 g of the polymerized crosslinked product (1) was charged into a 2-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel.
0 g was added to obtain a uniform dispersion. After raising the temperature of the reaction mixture to 80 ° C., the mixture was heated and stirred at the same temperature for 24 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered and washed with water. After neutralizing the obtained solid with 2000 ml of a 10% by weight aqueous sodium hydroxide solution,
Washed thoroughly with water. Then, it dried at 80 degreeC using a vacuum dryer for 10 hours, and obtained 700 g of sulfonic-acid-group containing polystyrene type | system | group polymer particles (henceforth this is called a dispersed phase particle (1)) of 6 micrometers in average particle diameter. In addition, the anion dissociation group density of the dispersed phase particles (1) was 4.2 mg equivalent / g.

30 g of the dispersed phase particles (1) were dried at 150 ° C. for 3 hours, and then the moisture in the atmosphere was absorbed to adjust the water content to 2.0% by weight. 4 g of the dispersion liquid (1) was added to 66 g of 20 cs silicone oil (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.), and the mixture was uniformly dispersed in a dispersion medium to obtain an electrorheological fluid (1) of the present invention. Obtained.

<Example 2> 3 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 was used instead of 20 cs of silicone oil. Oil (K manufactured by Shin-Etsu Chemical Co., Ltd.)
An electrorheological fluid (2) of the present invention was obtained in the same manner as in Example 1 except that 67 g of F96-10cs) was used.

<Example 3> Instead of the additive dispersion (1) in Example 1, 7 g of the additive dispersion (3) obtained in Reference Example 3 was used, and silicon oil (Shin-Etsu Chemical Co., Ltd.) was used.
An electrorheological fluid (3) of the present invention was obtained in the same manner as in Example 3, except that the amount of KF96-20cs manufactured by Toshiba was changed to 63 g.

Example 4 1.2 liters of water was charged into a 3 liter four-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, and charged with Kuraray Povar PVA-2.
05 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) 16.0
g of styrene, 270 g of styrene, 30 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene, 35% by weight of ethylstyrene, etc., manufactured by Wako Pure Chemical Industries, Ltd.) and azobisisobutyro. 8g of nitrile
Was added. Thereafter, the contents in the flask were dispersed at a stirring speed of 20,000 rpm,
Polymerized for hours. The obtained solid was separated by filtration, sufficiently washed with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain 293 g of a spherical polymer crosslinked product (hereinafter, referred to as a polymer crosslinked product (2)). I got

Then, 100 g of the crosslinked polymer (2) was charged into a 2 liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel.
g was added to obtain a uniform dispersion. The temperature of the reaction mixture is 8
After the temperature was raised to 0 ° C., the mixture was heated and stirred at the same temperature for 24 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered and washed with water. 10% by weight of the obtained solid
After neutralization with 500 ml of an aqueous sodium hydroxide solution, the resultant was sufficiently washed with water. Then, at 80 ° C. for 10 seconds using a vacuum dryer.
After drying for an hour, 173 g of sulfonic acid group-containing polystyrene-based polymer particles having an average particle diameter of 2.5 μm (hereinafter referred to as dispersed phase particles (2)) were obtained. The anion dissociation group density of the dispersed phase particles (2) was 4.1 mg equivalent / g.

30 g of the dispersed phase particles (2) were dried at 150 ° C. for 3 hours, and then the moisture in the atmosphere was absorbed to adjust the water content to 2.0% by weight. Then, the additive obtained in Reference Example 4 was obtained. 4 g of the dispersion liquid (4) was added to 66 g of silicone oil of 20 cs (KF96-20 cs manufactured by Shin-Etsu Chemical Co., Ltd.), and the mixture was uniformly dispersed in a dispersion medium to obtain an electrorheological fluid (4) of the present invention. Obtained.

<Example 5> Instead of the additive dispersion (4) in Example 4, 4 g of the additive dispersion (5) obtained in Reference Example 5 was used, and silicon oil (Shin-Etsu Chemical Co., Ltd.) was used.
An electrorheological fluid (5) of the present invention was obtained in the same manner as in Example 6, except that the amount of KF96-20cs) manufactured by the Company was changed to 66 g.

<Example 6> In place of the additive dispersion (1) in Example 1, 15 g of the additive dispersion (6) obtained in Reference Example 6 was used, and 10 cs of a mineral electric insulating oil ((trade name) ) An electrorheological fluid (6) of the present invention was obtained in the same manner as in Example 1 except that 55 g of Cosmo Oil (high pressure insulating oil) was used.

<Example 7> 10 cs of a mineral electric insulating oil (Co., Ltd.) was used in place of the additive dispersion (1) in Example 1 by using 6 g of the additive dispersion (7) obtained in Reference Example 7. An electrorheological fluid (7) of the present invention was obtained in the same manner as in Example 1 except that 64 g of Cosmo Oil (high pressure insulating oil) was used.

<Example 8> Instead of the additive dispersion (1) in Example 1, 4 g of the additive dispersion (8) obtained in Reference Example 8 was used, and silicon oil (Shin-Etsu Chemical Co., Ltd.) was used.
An electrorheological fluid (8) of the present invention was obtained in the same manner as in Example 1, except that the amount of KF96-20cs manufactured by Toshiba was changed to 66 g.

<Example 9> Instead of the additive dispersion (1) in Example 1, 4 g of the additive dispersion (9) obtained in Reference Example 9 was used, and silicon oil (Shin-Etsu Chemical Co., Ltd.) was used.
The electrorheological fluid (9) of the present invention was obtained in the same manner as in Example 1 except that the amount of KF96-20cs manufactured by Toshiba was changed to 66 g.

<Example 10> In place of the additive dispersion (1) in Example 1, 4 g of the additive dispersion (10) obtained in Reference Example 10 was used.
An electrorheological fluid (10) of the present invention was obtained in the same manner as in Example 1 except that the amount of KF96-20cs manufactured by K.K. was changed to 66 g.

<Example 11> Instead of the additive dispersion (1) in Example 1, 4 g of the additive dispersion (11) obtained in Reference Example 11 was used, and a silicone oil (Shin-Etsu Chemical Co., Ltd.) was used.
An electrorheological fluid (11) of the present invention was obtained in the same manner as in Example 1 except that the amount of KF96-20cs manufactured by K.K. was changed to 66 g.

<Example 12> 10 cs of a mineral electric insulating oil (Co., Ltd.) was used in place of the additive dispersion (1) in Example 1 by using 4 g of the additive dispersion (12) obtained in Reference Example 12. 66g of Cosmo Oil, high pressure insulating oil)
The electrorheological fluid (12) of the present invention was obtained in the same manner as in Example 1 except that the above was changed.

<Example 13> In place of the additive dispersion (1) in Example 1, 4 g of the additive dispersion (13) obtained in Reference Example 13 was used, and a 10 cs mineral electric insulating oil ((trade name) 66g of Cosmo Oil, high pressure insulating oil)
The electrorheological fluid (13) of the present invention was obtained in the same manner as in Example 1 except that the above was changed.

<Comparative Example 1> 30 g of the dispersed phase particles (1) in Example 1 was dried at 150 ° C. for 3 hours, and after absorbing moisture in the air to adjust the water content to 2.0% by weight,
cs silicon oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.)
-20 cs) to obtain a comparative electrorheological fluid (hereinafter referred to as comparative fluid (1)).

<Comparative Example 2> 30 g of the dispersed phase particles (1) in Example 1 was dried at 150 ° C. for 3 hours, and after absorbing moisture in the air to adjust the water content to 2.0% by weight, 10%.
cs silicon oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.)
-10 cs) was mixed and dispersed in 70 g to obtain an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (2)).

Comparative Example 3 30 g of the dispersed phase particles (1) in Example 1 were dried at 150 ° C. for 3 hours, and after absorbing moisture in the atmosphere to adjust the water content to 2.0% by weight,
The resulting mixture was mixed and dispersed in 70 g of cs mineral electric insulating oil (high pressure insulating oil, manufactured by Cosmo Oil Co., Ltd.) to obtain an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (3)).

Comparative Example 4 30 g of the dispersed phase particles (2) in Example 4 were dried at 150 ° C. for 3 hours, and after absorbing moisture in the air to adjust the water content to 2.0% by weight,
cs silicon oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.)
-20cs) to obtain a comparative electrorheological fluid (hereinafter referred to as comparative fluid (4)).

<Comparative Example 5> Instead of the additive dispersion (1) in Example 1, 1 g of the comparative additive (1) obtained in Reference Example 14 was used, and silicon oil (Shin-Etsu Chemical Co., Ltd.) was used.
An electrorheological fluid for comparison (hereinafter, referred to as comparative fluid (5)) was obtained in the same manner as in Example 1 except that the amount of KF96-20cs manufactured by Toshiba was changed to 69 g.

<Comparative Example 6> 1 g of the comparative additive (1) obtained in Reference Example 14 was used in place of the additive dispersion liquid (1) in Example 1, and 10 cs was used instead of silicone oil.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (6)) was prepared in the same manner as in Example 1 except that 69 g of a mineral-based electrical insulating oil (high-pressure insulating oil manufactured by Cosmo Oil Co., Ltd.) was used. .).

Comparative Example 7 Instead of the additive dispersion liquid (1) in Example 1, 10 g of a commercially available silicon-containing silicon-containing additive amino-modified silicone (KF8005 manufactured by Shin-Etsu Chemical Co., Ltd.) was used. An electrorheological fluid for comparison (hereinafter referred to as a comparative fluid) was prepared in the same manner as in Example 1 except that the amount of silicon oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to 60 g. (Referred to as (7)).

<Comparative Example 8> Instead of the additive dispersion (1) in Example 1, 4 g of the comparative additive dispersion (2) obtained in Reference Example 15 was used.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (8)) was obtained in the same manner as in Example 1, except that the amount of KF96-20cs manufactured by K.K. was changed to 66 g. .

<Comparative Example 9> Instead of the additive dispersion liquid (1) in Example 1, 4 g of the comparative additive dispersion liquid (3) obtained in Reference Example 16 was used.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (9)) was obtained in the same manner as in Example 1, except that the amount of KF96-20cs manufactured by K.K. was changed to 66 g. .

<Comparative Example 10> 4 g of the comparative additive dispersion (4) obtained in Reference Example 17 was used in place of the additive dispersion (1) in Example 1, and 1 g was used instead of silicone oil.
An electrorheological fluid for comparison (hereinafter referred to as Comparative Fluid (10)) was prepared in the same manner as in Example 3 except that 66 g of a mineral electric insulating oil of 0 cs (manufactured by Cosmo Oil Co., Ltd., high-pressure insulating oil) was used. .).

<Example 14> The electrorheological fluid (1) of the present invention obtained in Examples 1 to 13 and Comparative Examples 1 to 10
(13) and each of the comparative fluids (1) to (10) were measured for viscosity at 25 ° C. when no electric field was applied. Then, each of the electrorheological fluids was filled up to a height of 150 mm and a diameter of 100 mm from the bottom of a test tube having a diameter of 15 mm and sealed,
Thereafter, the mixture was allowed to stand at room temperature to track the sedimentation state of the dispersed phase particles. The height of the sedimentary layer formed by sedimentation of the dispersed phase particles in the electrorheological fluid was measured one day and one week after standing, and the dispersion stability of the electrorheological fluid was evaluated. Further, 50 ml of each electrorheological fluid was put in a 100 ml container, sealed, and allowed to stand at rest for one month, then the whole container was rotated at a speed of 30 rotations per minute, and the total number of rotations required to return to the original uniform state was measured. The redispersibility was evaluated. The results are shown in Tables 1 and 2.

Each of the electrorheological fluids was placed in a rotary viscometer with a coaxial electric field, and the gap between the inner and outer cylinders was 1.0 mm, and the shear rate was 4 mm.
00 / s, AC external electric field 4000V under the condition of temperature 25 ° C
/ Mm (frequency: 50 Hz) applied shear stress value (initial value) and current density flowing at that time (initial value)
Was measured. Further, after the viscometer was continuously operated at 25 ° C. for 3 days with an external electric field of 4000 V / mm applied, a shear stress value (a value after 3 days) and a current density (a value after 3 days) were measured. The temporal stability of the viscous fluid was investigated. The results are shown in Tables 1 and 2.

[0144]

[Table 1]

[0145]

[Table 2]

As is clear from Tables 1 and 2, the electrorheological fluids (1) to (13) of the present invention generate a large shear stress even by a relatively weak electric field, and the current density flowing at that time is small. It was excellent in current characteristics, excellent in stability of generated shear stress and current density with time, and further excellent in fluidity, dispersion stability and redispersibility in a state where no electric field was applied.

Electrorheological fluids (1), (3), (8)
(11) is a comparative fluid (1) using the same disperse phase and dispersion medium and no additive, a comparative fluid (5) and a comparative fluid (8) using styrene-based fine particles, and a dissolvable dispersion medium. Fluid stability and redispersibility compared with a comparative fluid (7) using a silicone-based additive of the type and a comparative fluid (9) using an additive (16) in which silica particles and a polymer are not complexed. , One of the liquidity was better.

The electrorheological fluid (2) is a comparative fluid (2)
And the electrorheological fluids (4) and (5) are comparative fluids (4)
It was found that the dispersion stability and the redispersibility were greatly superior to those of Comparative Example 1.

Electrorheological fluids (6), (7), (12),
(13) was found to be superior in dispersion stability and redispersibility even when the mineral oil-based electric insulating oil was used as the dispersion medium, as compared with the comparative fluid (3). Further, the dispersion stability was inferior to those of the comparative fluids (6) and (10).

[0150]

The electrorheological fluid obtained by the method of the present invention generates a large shear stress even when a relatively weak electric field is applied, and has an excellent current characteristic that a current density flowing at that time is small. Excellent stability over time of stress and current density, low initial viscosity when no electric field is applied, dispersion stability (can maintain electrorheological fluid in a uniform state for a long time without sedimentation or floating of dispersed phase) Engine mounts, clutches, dampers, and brakes because of their excellent performance and redispersibility (the ability to reproduce the original uniform state with a simple external force after the dispersed phase settles or floats and becomes non-uniform). ,shock absorber,
It can be effectively used for actuators, valves, etc.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H01B 3/46 H01B 3/46 B // (C10M 169/04 (C10M 169/04 107: 50 107: 50 155: 02) 155 : 02) C10N 10:08 C10N 10:08 40:08 40:08 40:14 40:14 70:00 70:00 (31) Priority claim number Japanese Patent Application No. 5-31520 (32) Priority date 1993 February 22, 1993.2.22 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-36323 (32) Priority date February 25, 1993 (1993. 2.25) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-36324 (32) Priority date February 25, 1993 (1993.2.25) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-36325 (32) Priority date February 25, 1993 (1993.2.25) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-36326 (32) Priority date February 25, 1993 (Feb. 25, 1993) (33) Countries claiming priority Japan (JP) (56) References JP-A-4-96997 (JP, A) JP-A-4-81496 (JP, A) JP-A-4-7397 (JP, A) JP-A-2-26633 (JP, A) JP-A-6-508655 (JP, A) Patent 3231420 (JP) , B2) Patent 3098331 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10M 155/02 C10M 107/50 C10M 169/04 C10M 177/00 C10N 10:08 C10N 40:08 C10N 40:14-40:16 C10N 70:00 B01F 17/54 B01J 13/00 H01B 3/46

Claims (9)

(57) [Claims] 1. A method for producing an electrorheological fluid in which a dispersed phase composed of dielectric particles is mixed and dispersed in a dispersion medium composed of an insulating liquid in the presence of an additive, wherein the additive is a polysiloxane. Forming particles (I) substantially insoluble in the insulating liquid in the presence of the polymer (II) or containing the polymer (II) in the presence of the particles (I) substantially insoluble in the insulating liquid. Wherein the polymer (II) is represented by the general formula (1): (Wherein, A represents —COO— or a phenylene group, R ¹ represents a hydrogen atom or a methyl group, and R ² has 1 to 1 carbon atoms.
6 alkylene groups, R ^{3 to} R ¹³ are the same or different and are an aryl group, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 carbon atom;
A represents an arbitrary integer, b and c represent the same or different integers of 0 to 10, and d represents an integer of 0 to 200, respectively. )) And a structural unit (A) containing polysiloxane represented by the following general formula (2): (Wherein, B represents —COO— or a phenylene group, R ¹⁴ represents a hydrogen atom or a methyl group, and R ¹⁵ represents 2 carbon atoms.
And R ¹⁶ is a hydrogen atom or an alkyl group, e is an arbitrary integer, and f is an integer of 2 to 100. A) an alkylene oxide chain-containing structural unit (B-1) represented by the following general formula (3): And a nitrogen-containing atom chain-containing structural unit (B-2) represented by the following general formula (4): (Wherein, E represents —COO— or a phenylene group, R ¹⁹ represents a hydrogen atom or a methyl group, and R ²⁰ represents a carbon atom of 6)
And i represents an arbitrary integer. An electrorheological fluid comprising at least one type of structural unit (B) containing a dispersed phase adsorptive chain selected from the group consisting of a long hydrocarbon chain-containing structural unit (B-3) represented by the following formula: Manufacturing method. 2. A polysiloxane-containing polymer (II) for particles (I) substantially insoluble in an insulating liquid in the composite.
Is from 100 parts by weight of the former to 100 parts by weight of the latter.
2. The preparation of the electrorheological fluid of claim 1 in the range of parts by weight .
Construction method . 3. The polysiloxane-containing polymer (II) comprises:
General formula (5) (Wherein, F represents —COO— or a phenylene group, R ²¹ represents a hydrogen atom or a methyl group, and R ²² represents a carbon atom of 1)
And R ^{23 to} R ³³ are the same or different and represent an aryl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, respectively. An integer of 10 to 10;
Are respectively shown. A silicon-based macromer (am) represented by), the general formula (6) embedded image (Wherein, G represents —COO— or a phenylene group, R ³⁴ represents a hydrogen atom or a methyl group, and R ³⁵ has 2 carbon atoms.
And R ³⁶ represents a hydrogen atom or an alkyl group, and m represents an integer of 2 to 100. A) an alkylene oxide chain-containing monomer (bm-1) represented by the general formula (7): In nitrogen-atom chain-containing monomer represented by (b-2) Contact good beauty one <br/> general formula (8) embedded image (Where K represents —COO— or a phenylene group, R ³⁹ represents a hydrogen atom or a methyl group, and R ⁴⁰ represents a carbon atom of 4)
Represents up to 30 alkyl groups. A long chain hydrocarbon chain-containing monomer (b-3) at least one disperse phase-adsorbing chain-containing monomer selected from the group consisting of (b) as essential component represented by), optionally 3. The method for producing an electrorheological fluid according to claim 1, which is obtained by polymerizing a monomer mixture (X) containing another monomer (d). 4. The ratio of the silicon-based macromer (am) to the monomer (b) containing the dispersed phase-adsorbing chain in the monomer mixture (X) is 10 to 90% by weight of the silicon-based macromer (am). Dispersed phase adsorptive chain-containing monomer (b) 10 to 90% by weight
4. The method for producing an electrorheological fluid according to claim 3 , wherein
Law . 5. The composite disperses and polymerizes a polymerizable monomer (α) in the presence of a polysiloxane-containing polymer (II) to form particles (I) substantially insoluble in an insulating liquid. The method according to any one of claims 1 to 4 , which is obtained by
5. A method for producing an electrorheological fluid according to any one of the above. 6. The method according to claim 5, wherein the insulating liquid is a silicon-based insulating oil . 7. The monomer (b) having a dispersed phase adsorptive chain in the monomer mixture (X) as a raw material component of the polysiloxane-containing polymer (II) is a monomer having a long hydrocarbon chain ( b-3)
The method for producing an electrorheological fluid according to claim 6 , wherein 8. The composite is obtained by emulsion-polymerizing a polymerizable monomer (α) in an aqueous medium in the presence of a polysiloxane-containing polymer (II) to form particles (I) substantially insoluble in an insulating liquid. ) is obtained by forming a claims 1-4
The method for producing an electrorheological fluid according to any one of the above. 9. The composite uses organic or inorganic fine particles having a polymerizable reactive group introduced therein as particles (I) substantially insoluble in an insulating liquid, and is used in the presence of the organic or inorganic fine particles. The electrorheological fluid according to any one of claims 1 to 4 , which is obtained by polymerizing the monomer mixture (X) to produce a polysiloxane-containing polymer (II) .
Manufacturing method .