JP2636446B2 - Electrorheological fluid composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrorheological fluid composition. More specifically, a large shear stress is generated even when a relatively weak electric field is applied, and the resulting shear stress is excellent in stability over time and has excellent dispersion stability when no electric field is applied. It relates to a fluid composition.

(Prior Art) An electrorheological fluid and a fluid obtained by dispersing and suspending solid particles in, for example, an insulating dispersion medium, whose rheological or flow properties are of the viscoplastic type due to an electric field change. This fluid is generally known as a fluid exhibiting the so-called Winslow effect, in which the viscosity increases significantly when an external electric field is applied to induce a large shear stress. Since this Windslow effect has the characteristic of quick response, the electrorheological fluid is used for clutches, dampers,
Applications to brakes, shock absorbers, actuators and the like have been attempted.

Conventionally, as an electrorheological fluid composition, solid particles such as cellulose, starch, soybean casein, silica gel, polystyrene-based ion-exchange resin, and crosslinked polyacrylate in insulating oils such as silicone oil, diphenyl chloride, and trans oil. Are known.

However, the electrorheological fluid composition using cellulose, starch or soybean casein as a dispersed phase has a problem that the shear stress obtained when an electric field is applied is small, and a crosslinked polyacrylate is used as the dispersed phase. The electrorheological fluid composition has a problem that only a relatively weak electric field is not applied to induce a practically sufficient shear stress.

An electrorheological fluid composition using an alkali metal salt type ion exchange resin of polystyrene sulfonic acid, a type of polystyrene ion exchange resin, as a disperse phase can obtain a large shear stress even when a relatively weak electric field is applied. Over time, there is a problem that the stability over time is poor.

Furthermore, since the true specific gravity of an alkali metal salt type ion exchange resin of polystyrene sulfonic acid is as large as 1.5, an electrorheological fluid composition prepared using a liquid having a specific gravity of about 1.0, such as silicon oil or a hydrocarbon solvent, as a dispersion medium. The material has a problem that the dispersion stability in a state where no electric field is applied is poor. When a halide having a large specific gravity is used as a dispersion medium, there is a problem in toxicity of the dispersion medium.

(Problems to be Solved by the Invention) The present invention is to solve the above-mentioned problems of the conventional electrorheological fluid composition.

Therefore, an object of the present invention is to provide a high shear stress even when a relatively weak electric field is applied and to maintain the shear stress over a long period of time. Another object of the present invention is to provide an excellent electrorheological fluid composition.

(Means and Actions for Solving the Problems) The present invention provides a monomer mixture (A) comprising a vinyl aromatic compound (a) and a polyvinyl compound (b) as essential components and optionally adding another vinyl compound (c). The particles of the polymerized crosslinked product (I) may be used without solvent or in the polymerized crosslinked product (I).
To a polymer core having a specific gravity of 1.3 or less obtained by sulfonation in the presence of a non-swelling solvent.
To a polymer particle having a core-shell structure having an average particle diameter in the range of 1.0 to 100 μm having a shell made of a polymer crosslinked product having a sulfonic acid group with a thickness of ~ 5.0 μm, The present invention relates to an electrorheological fluid composition obtained by dispersing dispersed phase particles in water containing 10 parts by weight or less of water and dispersing the dispersed phase particles in an insulating dispersion medium.

The sulfonic acid group referred to in the present invention is a substance which releases a cation in the presence of a polar solvent such as water and turns itself into a sulfonic acid ion, and particularly a cation released in the presence of a polar solvent such as water. No restrictions.

It is necessary that the average particle diameter of the polymer particles having a nucleus-shell structure to be used as the dispersed phase particles used in the present invention is in the range of 1.0 to 100 μm. The average particle size of the dispersed phase particles is 1.0μ
If it is less than m, a problem occurs that a large shear stress cannot be obtained when an electric field is applied to the prepared electrorheological fluid composition. Further, the average particle diameter of the dispersed phase particles is 100
If it exceeds μm, the shear stress value obtained when a certain electric field is applied to the prepared electrorheological fluid composition becomes irregular, which causes a problem that it is difficult to stabilize.

Polymer particles serving as the dispersed phase particles used in the present invention,
It is necessary to have a shell layer of a crosslinked polymer having a sulfonic acid group having a thickness of 0.3 to 5.0 μm on its surface. When the thickness of the surface shell layer is less than 0.3 μm, there is a problem that a large shear stress cannot be obtained when an electric field is applied to the prepared electrorheological fluid composition. When the thickness of the surface shell layer exceeds 5.0 μm, not only the further improvement of the Winslow effect by the introduction of the sulfonic acid group is not recognized, but also the specific gravity of the dispersed phase particles becomes unnecessarily large, A problem arises in that the prepared electrorheological fluid composition has poor dispersion stability when no electric field is applied.

Polymer particles serving as the dispersed phase particles used in the present invention,
It is necessary to have a core portion composed of a polymer having a specific gravity of 1.3 or less. In particular, a polymer having a specific gravity in the range of 0.8 to 1.1 is preferable as one constituting such a core portion. When the specific gravity of the core portion exceeds 1.3, there arises a problem that the dispersion stability cannot be obtained unless a highly toxic halide is used as a dispersion medium.

As a method for obtaining polymer particles having a nucleus-shell structure as a dispersed phase particle used in the present invention, for example, a vinyl aromatic compound (a) and a polyvinyl compound (b) are essential components, and other vinyl The monomer mixture (A) to which the compound (c) has been added is polymerized by a known method, and the resulting polymer crosslinked product (I) is pulverized to an appropriate particle size if necessary, and then, without solvent or under polymerization crosslinking. A method of reacting with a sulfonating agent in the presence of a solvent having a specific swelling relative to the polymer (I) to introduce a sulfonic acid group in a range of 0.3 to 5.0 μm from the surface of the particles of the polymerized crosslinked product (I). Can be mentioned.

Monomer mixture (A) that can be used in the present invention
Is a vinyl aromatic compound (a) of 10.0 to 99.9.
Mol%, the polyvinyl compound (b) is preferably in the range of 0.1 to 90.0 mol%. Vinyl aromatic compound (a)
Is less than 10.0 mol% and the composition ratio of the polyvinyl compound (b) is more than 90.0 mol%, sulfonation does not easily proceed, or an electric field is applied to the electrorheological fluid composition using the obtained particles. May cause a problem that a large shear stress cannot be obtained when is applied. The composition ratio of the vinyl aromatic compound (a) was 99.9 mol%.
When the ratio is more than 0.1 and the constituent ratio of the polyvinyl compound (b) is less than 0.1 mol%, a problem may occur that particles adhere to each other when the crosslinked polymer obtained by polymerization is sulfonated.

Examples of the vinyl aromatic compound (a) that can be used in the present invention include styrene, vinyl naphthalene,
Vinyl aromatic hydrocarbons such as vinyl anthracene and vinyl phenanthrene; methyl styrene, ethyl styrene,
Monoalkylstyrene compounds such as propylstyrene, butylstyrene, pentylstyrene, hexylstyrene; dimethylstyrene, diethylstyrene, dipropylstyrene, methylethylstyrene, methylpropylstyrene, methylhexylstyrene, ethylbutylstyrene, ethylpropylstyrene, ethylhexylstyrene , Dialkylstyrene compounds such as propylbutylstyrene; trimethylstyrene, triethylstyrene, tripropylstyrene, methyldiethylstyrene, dimethylethylstyrene, methylethylpropylstyrene, methyldipropylstyrene, dimethylpropylstyrene,
Trialkylstyrene compounds such as ethyldipropylstyrene and diethylpropylstyrene; vinylmonoalkylnaphthalene compounds such as vinylmethylnaphthalene, vinylethylnaphthalene and vinylpropylnaphthalene; vinyldimethylnaphthalene and vinyldiethylnaphthalene;
Vinyl dialkyl naphthalene compounds such as vinyl dipropyl naphthalene and vinyl methyl ethyl naphthalene; vinyl trialkyl naphthalene such as vinyl trimethyl naphthalene, vinyl triethyl naphthalene, vinyl tripropyl naphthalene, vinyl methyl diethyl naphthalene, vinyl dimethyl ethyl naphthalene, and vinyl methyl ethyl propyl naphthalene Compound: chlorostyrene, bromostyrene, fluorostyrene, chloromethylstyrene, chloroethylstyrene, chloropropylstyrene, chlorodimethylstyrene, bromomethylstyrene, bromoethylstyrene, fluoromethylstyrene, fluoroethylstyrene, vinylchloronaphthalene, vinylbromonaphthalene Halogenated vinyl aromatic compounds such as methoxystyrene, dimethoxy Styrene, trimethoxystyrene, ethoxystyrene, diethoxystyrene, triethoxystyrene, propyloxystyrene, dipropyloxystyrene, tripropyloxystyrene, phenoxystyrene, methoxymethylstyrene, methoxyethylstyrene, methoxypropylstyrene, ethoxymethylstyrene, Ethoxyethylstyrene, propyloxymethylstyrene, propyloxyethylstyrene, phenoxymethylstyrene, phenoxyethylstyrene, methoxydimethylstyrene, methoxydiethylstyrene, phenoxydimethylstyrene, phenoxydiethylstyrene, methoxychlorostyrene, methoxybromostyrene, vinylmethoxynaphthalene, Vinyl dimethoxy naphthalene, vinyl ethoxy naphthalene, vinyl Alkoxy or aryloxy such as diethoxynaphthalene, vinylmethoxymethylnaphthalene, vinylmethoxydimethylnaphthalene, vinyldimethoxymethylnaphthalene, vinylmethoxyethylnaphthalene, vinylmethoxydiethylnaphthalene, vinyldimethoxyethylnaphthalene, vinylmethoxychloronaphthalene, vinyldimethoxychloronaphthalene, etc. And vinyl aromatic compounds, and one or more of them can be used.

Examples of the polyvinyl compound (b) that can be used in the present invention include divinylbenzene, divinyltoluene, divinylxylene, divinylethylbenzene,
Polyvinyl aromatic hydrocarbons such as divinyldiethylbenzene, divinylpropylbenzene, divinylnaphthalene, trivinylbenzene, trivinyltoluene, trivinylxylene, and trivinylnaphthalene; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and trimethylol Examples thereof include polyvinyl aliphatic compounds such as propane tri (meth) acrylate, N, N'-methylenebisacrylamide, diallyl maleate, and diallyl adipate, and one or more of these can be used.

In the monomer mixture (A) in the present invention, a vinyl compound (c) other than the vinyl aromatic compound (a) or the polyvinyl compound (b) can be blended as necessary, and the constituent ratio is 50 mol% or less. Is preferable. Examples of such other vinyl compounds (c) include olefinic hydrocarbons such as ethylene, propylene, isoprene, butadiene, vinyl chloride, and chloroprene or halogen-substituted products thereof; methyl (meth) acrylate, ethyl (meth) Ester compounds of unsaturated carboxylic acids such as acrylates; vinyl ester compounds of monovalent carboxylic acids such as vinyl acetate and vinyl propionate;
(Meth) acrylamide, diacetone acrylamide,
Unsaturated amide compounds such as methylolated (meth) acrylamide or derivatives thereof; unsaturated cyanide compounds such as (meth) acrylonitrile and crotonnitrile; unsaturated alcohol compounds such as (meth) allyl alcohol and croton alcohol; (meth) acrylic acid Unsaturated monobasic acids such as maleic acid, fumaric acid, itaconic acid; monoesters of monohydric alcohols such as maleic acid monomethyl ester and maleic acid monoallyl ester with unsaturated dibasic acids Compounds and the like can be mentioned, and one or more of these can be used.

The shape of the dispersed phase particles used in the present invention is preferably spherical or elliptical spherical. In the case where the shape of the dispersed phase particles is other than spherical or elliptical spherical, the problem that a large shear stress cannot be obtained when an electric field is applied to the prepared electrorheological fluid composition or the electric field was continuously applied. There may be a problem that the stability over time in the state is poor.

The method for producing the particles of the polymer crosslinked product (I) used as an intermediate in obtaining the polymer particles having a core-shell structure in the present invention is not particularly limited, and a known polymerization method or a granulation method may be used. Adopt it. Examples of the polymerization method include, for example, a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, a solution polymerization method, a bulk polymerization method, and the like. A method in which particles are easily obtained is preferred. Therefore, in the production of the crosslinked polymer (I), a suspension polymerization method or an emulsion polymerization method is preferred.

When the suspension polymerization method is used for producing the particles of the polymer crosslinked product (I) used in the present invention, the conditions for the polymerization are not particularly limited.

Water or the like is usually used as a dispersion medium for suspension polymerization.

As a dispersant for the suspension polymerization, known dispersants such as polyvinyl alcohol, carboxymethylcellulose, ammonium salts of styrene-maleic anhydride copolymer, bentonite, sodium poly (meth) acrylate, and poly (diallylmethylammonium chloride) are usually used. Things can be used.

Examples of the polymerization initiator for suspension polymerization include peroxides such as benzoyl peroxide, tertiary butyl hydroxy peroxide, cumene peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, tertiary butyl perphthalate, and caproyl peroxide. Oxides; azo such as azoisobutyronitrile, azoisobutylamide, 2,2'-azobis (2,4-dimethylmaleronitrile), azobis (α-dimethylvaleronitrile), azobis (α-methylbutyronitrile) Compounds and the like can be mentioned, and one or more of these can be used.

In suspension polymerization, if necessary, a known emulsion polymerization inhibitor can be used to suppress the generation of fine particles.

Suspension polymerization is usually carried out at a temperature in the range of 50-100 ° C.
It takes about 30 hours.

As the operation of suspension polymerization, for example, water and a dispersing agent are charged, a mixture of monomers in which a polymerization initiator is dissolved is added under stirring, and the particle size is regulated using a dispersing machine or a stirring device. The reaction is carried out at a predetermined temperature in a suspended state.

When the emulsion polymerization method is used to produce the particles of the crosslinked polymer (I) used in the present invention, the conditions for the polymerization are not particularly limited.

Water or the like is usually used as a solvent for emulsion polymerization.

As the emulsifier for the emulsion polymerization, a known one such as a surfactant such as sodium lauryl sulfonate and polyoxyethylene stearate can be used.

As the polymerization initiator for the emulsion polymerization, generally known ones such as sodium persulfate and ammonium persulfate can be used.

Emulsion polymerization is usually carried out at a temperature in the range of 50-100 ° C.
It takes about 40 hours.

As the operation of emulsion polymerization, for example, known methods such as a seed polymerization method, a temporary charging polymerization method, a monomer addition polymerization method, and an emulsion addition polymerization method can be used.

In order to perform the seed polymerization method, usually, first, seed particles, water, an emulsifier, and the like are charged into a reaction vessel, uniformly dispersed under stirring, and then a part or all of the monomer mixture is added as necessary. Next, after heating to a predetermined temperature, a polymerization initiator is added to start the reaction. Furthermore, the remainder of the monomer mixture is added continuously or intermittently, and the emulsification is carried out at a predetermined temperature.

The polymer crosslinked product (I) in the present invention may be a substantially non-porous polymer crosslinked product called a gel type, or a known porous forming agent that imparts porosity to the polymer crosslinked product, such as a swellable polymer. Or a non-swellable organic solvent, a linear polymer soluble in a monomer, or a crosslinked porous polymer obtained by polymerizing a monomer mixture in the presence of a mixture thereof.

The polymer particles having a nucleus-shell structure as the dispersed phase particles used in the present invention are obtained by sulfonating the polymer crosslinked product (I) obtained by the above polymerization method under specific conditions.

That is, when producing polymer particles having a core-shell structure, it is necessary to sulfonate the polymer crosslinked product (I) in the absence of a solvent or in the presence of a solvent that is non-swellable with respect to the polymer crosslinked product (I). is there.

Examples of the solvent that is non-swellable with respect to the polymer crosslinked product (I) include:
Any solvent may be used as long as it does not swell the polymer crosslinked product (I) and is inert to the sulfonating agent, and examples thereof include aliphatic hydrocarbons such as hexane, cyclohexane, and ligroin. The use amount of these solvents is preferably within a range of 1,000 parts by weight or less based on 100 parts by weight of the crosslinked polymer (I).

When the sulfonation is carried out in the absence of a solvent or in the presence of a non-swelling solvent, the sulfonic acid groups are introduced from the surface of the crosslinked polymer (I). Therefore, the thickness of the shell layer composed of the polymerized crosslinked product having a sulfonic acid group can be determined mainly by adjusting the activity of the sulfonic acid agent, the reaction temperature, and the reaction time. In the present invention, the crosslinked polymer (I)
When a swelling solvent is used instead, the sulfonic acid group is quickly introduced into the polymer crosslinked product (I), and as a result, a predetermined thickness of the polymer crosslinked product having a sulfonic acid group is obtained. The shell layer cannot be formed.

The sulfonating agent is not particularly restricted but includes, for example, sulfuric acid, fuming sulfuric acid, chlorosulfuric acid and the like, and one or more of these can be used.

The sulfonation reaction is usually performed at a temperature in the range of -20 to 120C for about 0.3 to 48 hours.

The polymer particles having a nucleus-shell structure obtained by sulfonating the polymerized crosslinked product (I) in this manner are separated from the sulfonating agent, and then removed with a large amount of water to remove acids and the like remaining in the particles. It is good to wash thoroughly. Then, if necessary, the cation of the sulfonic acid group can be changed from a proton to a suitable cation species by a method such as neutralization or ion exchange.

The cation of the sulfonic acid group present in the polymer particles having a nucleus-shell structure serving as the dispersed phase particles used in the present invention is not particularly limited, and is, for example, hydrogen; an alkali metal such as lithium, sodium, or potassium; magnesium,
Alkaline earth metals such as calcium; aluminum etc.
Group IIIA metals; Group IVA metals such as tin and lead; cations such as transition metals such as zinc and iron; or ammonium, organic quaternary ammonium, pyridinium, guadinium and the like. One or more of these can be used.

The dispersed phase particles used in the present invention can be obtained by adding water to the above-mentioned polymer particles having a core-shell structure. In the electrorheological fluid composition of the present invention, since a small amount of water is contained in the dispersed phase particles, a large shear stress is induced when an electric field is applied.

The water in the dispersed phase particles in the present invention needs to be 10 parts by weight or less based on 100 parts by weight of the particles. 10 water
If the amount is more than the weight part, the dispersed phase particles adhere to each other or the prepared electrorheological fluid composition has a reduced insulating property, so that a large current flows when an electric field is applied, which is not preferable.

 As an insulating dispersion medium that can be used in the present invention
Is not particularly limited, for example, polydimethylsiloxane,
Silicone oils such as polyphenylmethylsiloxane;
Liquid paraffin, decane, dodecane, methylnaphthale
Dimethylnaphthalene, ethylnaphthalene, biphenyl
Carbon such as triphenyl, delican and partially hydrogenated triphenyl
Hydrogen; ether compounds such as diphenyl ether;
Lobenzene, dichlorobenzene, trichlorobenzene,
Bromobenzene, dibromobenzene, chloronaphthale
, Dichloronafretane, bromonaphthalene, chlorobi
Phenyl, dichlorobiphenyl, trichlorobiphenyl
, Bromobiphenyl, chlorodiphenylmethane, dic
Lorodiphenylmethane, trichlorodiphenylmethane,
Bromodiphenylmethane, chlorodecane, dichlorodeca
, Trichlorodecane, brocadecan, chlorododeca
, Dichlorododecane and bromododecane
Hydrocarbons: chlorodiphenyl ether, dichlorodiph
Phenyl ether, trichlorodiphenyl ether, bro
Halogenated diphenyl ethers such as modiphenyl ether
Ter compound; Daifoil (Manufactured by Daikin Industries, Ltd.)
And Demnum Fluoride such as (made by Daikin Industries, Ltd.)
Products: dioctyl phthalate, trioctyl trimellitate
And ester compounds such as dibutyl sebacate.
One or more of these can be used
Can be

The electrorheological fluid composition of the present invention is obtained by dispersing the above-mentioned dispersed phase particles in an insulating dispersion medium, and the ratio between the dispersed phase particles and the insulating dispersion medium in the composition is based on 100 parts by weight of the former. The latter is preferably in the range of 50 to 500 parts by weight. When the amount of the dispersion medium exceeds 500 parts by weight, the shear stress obtained when an electric field is applied to the prepared electrorheological fluid composition may not be sufficiently large. 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.

In the present invention, in order to improve the dispersibility of the dispersed phase particles in the dispersion medium or to adjust the viscosity or the shear stress of the electrorheological fluid composition, for example, a surfactant, a polymer dispersant, a polymer thickener, etc. Various additives can be added to the composition.

(Effect of the Invention) The electrorheological fluid composition of the present invention can obtain a large shear stress even when a relatively weak external electric field is applied, has excellent stability over time of the generated shear stress, and has an applied electric field. Since it has excellent dispersion stability in the absence of a fluid, it can be effectively used for clutches, dampers, brakes, shock absorbers, actuators, and the like.

(Examples) Hereinafter, the present invention will be described with reference to examples, but the scope of the present invention is not limited to only these examples.

REFERENCE EXAMPLE 1 Four-liter three-liter port equipped with a stirrer, reflux condenser and thermometer
Charge 1.2 l of water into a separable flask,
Cole (Kuraray Co., Ltd., Kuraray Povar) PVA-205)
After adding and dissolving 16.0 g, further, styrene 250 g,
Industrial divinylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.
A mixture of 55% by weight of nilbenzene and 35% by weight of ethylstyrene
Compound) 50g and a mixture consisting of 5g of benzoyl peroxide
added. Then, the contents in the flask at a stirring speed of 600 rpm
The product was dispersed and polymerized at 80 ° C. for 6 hours. The solid obtained
After filtration and washing thoroughly with water, use a hot air drier at 80 ° C.
And dried for 12 hours.
It is referred to as a crosslinked product (1). ｝ 285 g was obtained.

When the specific gravity of the polymer crosslinked product (1) was measured by a sedimentation method, it was 1.05.

Reference Example 2 Three-liter four-neck equipped with a stirrer, reflux condenser and thermometer
Charge 1.2 l of water into a separable flask,
Cole (Kuraray Co., Ltd., Kuraray Povar) PVA-205)
After adding and dissolving 10.0 g, further 200 g of styrene,
50 g of methylstyrene, same industrial grade as used in Reference Example 1
30 g of divinylbenzene and azobisisobutyronitrile
A mixture consisting of 4 g of toluene was added. After that, stirring speed of 400rpm
Disperse the contents in the flask at a temperature and polymerize at 70 ° C for 8 hours
did. The solid obtained is filtered off, washed thoroughly with water and then heated.
Dry at 80 ° C for 12 hours using an air dryer, and use a spherical polymer
Bridges. Hereinafter, this is referred to as a polymer crosslinked product (2). ｝ 260g
Obtained.

The specific gravity of the polymer crosslinked product (2) was measured by a sedimentation method and found to be 1.07.

Reference Example 3 Three-liter four-hole equipped with a stirrer, reflux condenser and thermometer
Charge 1.2 l of water into a separable flask,
Cole (Kuraray Co., Ltd., Kuraray Povar) PVA-205)
After adding and dissolving 16.0 g, further, styrene 250 g,
The same industrial divinyl benzene 60 used in Reference Example 1
g, isooctane 300 g and azobisisobutyronitrile
A mixture consisting of 12 g of toluene was added. Then, the disperser (rotating
Number: 5000 rpm) to disperse the contents in the flask,
Polymerization was carried out at 70 ° C. for 8 hours. The solid obtained is filtered off and
After washing with acetone and water, use a hot air drier to
And dried for 12 hours.
It is called a crosslinked product (3). ｝ 290 g was obtained.

The specific gravity of the polymer crosslinked product (3) was measured by a precipitation method and found to be 1.04.

Reference Example 4 After charging 50 ml of water, 0.4 g of sodium lauryl sulfonate and 1.0 g of dodecane into a 300 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, the mixture was emulsified using a disperser. I let it. Further, after adding 50 ml of water, 0.2 g of sodium persulfate, 40 g of styrene and 20 g of the same industrial divinylbenzene used in Reference Example 1,
By heating at 50 ° C. for 8 hours with stirring to carry out polymerization, 160 ml of an emulsion of seed particles was obtained.

Then, 1.2 l of water was charged into a 3 l four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, and 160 ml of the seed particle emulsion prepared above and 2.8 g of sodium lauryl sulfonate were added. And uniformly dispersed under stirring. Then, while maintaining the rotation speed of the stirrer at 200 rpm, 70
2 g of sodium persulfate dissolved in 10 ml of water
Was added. Then, a mixture of 160 g of styrene and 80 g of the same industrial divinylbenzene used in Reference Example 1 was added to 18
It was added dropwise over time. Further, after reacting at the same temperature for 4 hours, the temperature was raised to 90 ° C., and the reaction was terminated after 2 hours.

The solid content of the obtained latex was separated by filtration and dried at 80 ° C. for 12 hours using a hot air drier to obtain a spherical polymer crosslinked product (hereinafter referred to as polymer crosslinked product (4)). ｝ 270 g was obtained.

The specific gravity of the polymer crosslinked product (4) was measured by a sedimentation method and found to be 1.06.

Reference Example 5 Three-liter four-neck equipped with a stirrer, reflux condenser and thermometer
Charge 1.2 l of water into a separable flask,
Cole (Kuraray Co., Ltd., Kuraray Povar) PVA-205)
After adding and dissolving 16.0 g, further, styrene 250 g,
Methoxystyrene 10g, same industry as used in Reference Example 1
Divinylbenzene 40g and azobisisobutyronite
A mixture consisting of 12 g of ril was added. Then, the dispersing machine (time
(Inversion number: 3000 rpm) to disperse the contents in the flask.
And polymerized at 70 ° C. for 9 hours.

The obtained solid was separated by filtration, thoroughly washed with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain a spherical polymer crosslinked product (hereinafter referred to as polymer crosslinked product (5), 284 g). I got

The specific gravity of the polymer crosslinked product (5) was measured by a precipitation method and found to be 1.06.

Example 1 500 g of 98% by weight concentrated sulfuric acid was charged into one 4-neck separable flask equipped with a stirrer and a thermometer, and 50 g of the polymer crosslinked product (1) obtained in Reference Example 1 was added, followed by stirring for 30 minutes. Thus, a uniform dispersion was obtained. Then, the contents of the flask are
The temperature was raised to 80 ° C., and the mixture was heated and stirred at the same temperature for 12 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. 10% by weight of the obtained solid
After neutralization with 80 ml of an aqueous sodium hydroxide solution, the mixture was sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum dryer, and 66 g of spherical dispersed phase particles (hereinafter referred to as dispersed phase particles (1)). I got｝.

When the average particle diameter of the obtained dispersed phase particles (1) was measured using a particle size distribution analyzer (SALD-1000, manufactured by Shimadzu Corporation), it was 50 μm. When the ion exchange capacity of the dispersed phase particles (1) was measured by neutralization titration, 2.7 mg
Equivalent / g. It was 1.22 when the specific gravity of the dispersed phase particle (1) was measured using the sedimentation method.

When the water content in the obtained dispersed phase particles (1) was measured using a Karl Fischer moisture meter (MPS-3P, manufactured by Kyoto Electronics Industry Co., Ltd.), it was 2.1 parts by weight.

Scanning electron microscope (manufactured by Shimadzu Corporation, EMX-SM
When the cross section of the dispersed phase particles (1) was observed at a magnification of 1000 times using (7), an image as shown in FIG. 1 was obtained. As is apparent from FIG. 1, the dispersed phase particles (1) were
It had a shell structure, and the thickness of the shell layer was 4.0 μm.
Further, when the X-ray intensity of the scanning electron microscope (magnification: 1000) was increased to analyze the sulfur element in the cross section of the dispersed phase particles (1), an image as shown in FIG. 2 was obtained. As apparent from FIG. 2, the sulfonic acid groups in the dispersed phase particles were present only in the peripheral portions of the particles. From the above results, it was found that the dispersed phase particles (1) had a layer having a sulfonic acid group with a thickness of 4.0 μm as a shell layer.

 30 g of the obtained dispersed phase particles (1) were used in Shin-Etsu Silicon Oil
KF96-300CS (Shin-Etsu Chemical Co., Ltd.
Con oil) mixed and dispersed in 70 g of
Fluid composition (hereinafter referred to as fluid composition (1))
U. I got｝.

Example 2 500 g of 98% by weight concentrated sulfuric acid was charged into one 4-neck separable flask equipped with a stirrer and a thermometer, and 50 g of the polymer crosslinked product (1) obtained in Reference Example 1 was added, followed by stirring for 30 minutes. Thus, a uniform dispersion was obtained. Then, the contents of the flask are
The temperature was raised to 80 ° C., and the mixture was heated and stirred at the same temperature for 3 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. 10% by weight of the obtained solid
After neutralization with 25 ml of an aqueous sodium hydroxide solution, the mixture was sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours by using a vacuum drier, and is referred to as “dispersed phase particles (2)” in the form of 52 g of spherical dispersed phase particles. I got｝.

When the average particle size of the obtained dispersed phase particles (2) was measured using a particle size distribution analyzer, it was 50 μm. When the ion exchange capacity of the dispersed phase particles (2) was measured by neutralization titration, it was 1.0 mg equivalent / g. The specific gravity of the dispersed phase particles (2) was determined to be 1.10.

When the water content in the dispersed phase particles (2) was measured using a Karl Fischer moisture meter, it was 1.5 parts by weight.

When the cross section of the dispersed phase particles (2) was observed using a scanning electron microscope, the dispersed phase particles (2) also had a core-shell structure like the dispersed phase particles (1), and the shell layer was Thickness 1.0
It was found that the layer had a sulfonic acid group of μm.

 30 g of the obtained dispersed phase particles (2) was
Le KF96-300CS (Shin-Etsu Chemical Co., Ltd.
Recon oil) mixed and dispersed in 70 g
Viscous fluid composition (hereinafter referred to as fluid composition (2))
U. I got｝.

Example 3 500 g of chlorosulfuric acid was charged into one four-neck separable flask equipped with a stirrer and a thermometer, and was cooled to 0 ° C. using an ice bath.
After cooling, the polymer crosslinked product (2)
g was added and stirred at the same temperature for 3 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. The obtained solid was neutralized with 30 ml of a 10% by weight aqueous sodium hydroxide solution, and then sufficiently washed with water. Then
It is dried at 80 ° C. for 10 hours using a vacuum drier, and is 53 g of spherical dispersed phase particles, hereinafter referred to as dispersed phase particles (3). I got｝.

When the average particle diameter of the obtained dispersed phase particles (3) was measured using a particle size distribution analyzer, it was 80 μm. The ion exchange capacity of the dispersed phase particles (3) measured by neutralization titration was 1.1 mg equivalent / g. The specific gravity of the dispersed phase particles (3) was measured using a sedimentation method and found to be 1.11.

When the water content in the dispersed phase particles (3) was measured using a Karl Fischer moisture meter, it was 1.3 parts by weight.

When the cross section of the dispersed phase particles (3) was observed using a scanning electron microscope, the dispersed phase particles (3) also had a core-shell structure like the dispersed phase particles (1), and the shell layer was Thickness 1.9
It was found that the layer had a sulfonic acid group of μm.

 30 g of the obtained dispersed phase particles (3) was
Le KF96-300CS (Shin-Etsu Chemical Co., Ltd.
Recon oil) mixed and dispersed in 70 g
Viscous fluid composition (hereinafter referred to as fluid composition (3))
U. I got｝.

Example 4 500 g of 98% by weight concentrated sulfuric acid was charged into one 4-neck separable flask equipped with a stirrer and a thermometer, and 50 g of the crosslinked polymer (3) obtained in Reference Example 3 was added, followed by stirring for 30 minutes. Thus, a uniform dispersion was obtained. Then, the contents of the flask are
The temperature was raised to 80 ° C., and the mixture was heated and stirred at the same temperature for 5 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. 10% by weight of the obtained solid
After neutralization with 80 ml of an aqueous sodium hydroxide solution, the mixture was sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum dryer, and 63 g of spherical dispersed phase particles (hereinafter referred to as dispersed phase particles (4)). I got｝.

When the average particle diameter of the obtained dispersed phase particles (4) was measured using a particle size distribution analyzer, it was 10 μm. When the ion exchange capacity of the dispersed phase particles (4) was measured by neutralization titration, it was 2.7 mg equivalent / g. The specific gravity of the dispersed phase particles (4) was measured by a sedimentation method and found to be 1.23.

When the water content in the dispersed phase particles (4) was measured using a Karl Fischer moisture meter, it was 1.8 parts by weight.

When the cross section of the dispersed phase particles (4) was observed using a scanning electron microscope, the dispersed phase particles (4) also had a core-shell structure like the dispersed phase particles (1), and the shell layer was 0.8 thickness
It was found that the layer had a sulfonic acid group of μm.

 30 g of the obtained dispersed phase particles (4) 900 (new
70 g of partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.
Mixed and dispersed in the electrorheological fluid composition of the present invention.
Below, this is called fluid composition (4). I got｝.

Example 5 500 g of 98% by weight concentrated sulfuric acid was charged into one 4-neck separable flask equipped with a stirrer and a thermometer, and 50 g of the polymer crosslinked product (4) obtained in Reference Example 4 was added, followed by stirring for 30 minutes. Thus, a uniform dispersion was obtained. Then, the contents of the flask are
The temperature was raised to 80 ° C., and the mixture was heated and stirred at the same temperature for 3 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. 10% by weight of the obtained solid
After neutralization with 80 ml of an aqueous sodium hydroxide solution, the mixture was sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours by using a vacuum drier, and is referred to as dispersed phase particles (5) below, in an amount of 68 g of spherical dispersed phase particles. I got｝.

When the average particle diameter of the obtained dispersed phase particles (5) was measured using a particle size distribution analyzer, it was 5 μm. The ion exchange capacity of the dispersed phase particles (5) measured by neutralization titration was 2.6 mg equivalent / g. The specific gravity of the dispersed phase particles (5) was measured using a sedimentation method and found to be 1.24.

The water content in the dispersed phase particles (5) was measured using a Karl Fischer moisture meter, and was 2.3 parts by weight.

When the cross section of the dispersed phase particles (5) was observed using a scanning electron microscope, the dispersed phase particles (5) also had a core-shell structure like the dispersed phase particles (1), and the shell layer was Thickness 0.4
It was found that the layer had a sulfonic acid group of μm.

 30 g of the obtained dispersed phase particles (5) were used in Shin-Etsu Silicon Oil
KF96-20CS (dimethylsilicon manufactured by Shin-Etsu Chemical Co., Ltd.)
Oil) mixed and dispersed in 70 g
Fluid composition {hereinafter, referred to as fluid composition (5). ｝
I got

Example 6 500 g of chlorosulfuric acid was charged into one four-neck separable flask equipped with a stirrer and a thermometer, and was cooled to 0 ° C. using an ice bath.
After cooling, the polymer crosslinked product (5)
g was added and stirred for 3 hours to obtain a uniform dispersion. Next, the mixture was removed from the ice bath and stirred at room temperature for 3 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. The obtained solid was neutralized with 70 ml of a 10% by weight aqueous solution of lithium hydroxide, and then sufficiently washed with water. Then, using a vacuum dryer, dried at 80 ° C. for 10 hours, 72 g
Hereinafter, these are referred to as dispersed phase particles (6). I got｝.

When the average particle diameter of the obtained dispersed phase particles (6) was measured using a particle size distribution analyzer, it was 15 μm. The ion exchange capacity of the dispersed phase particles (6) measured by neutralization titration was 3.6 mg equivalent / g. The specific gravity of the dispersed phase particles (6) measured by the sedimentation method was 1.27.

When the water content of the dispersed phase particles (6) was measured using a Karl Fischer moisture meter, it was 2.1 parts by weight.

When the cross section of the dispersed phase particles (6) was observed using a scanning electron microscope, the dispersed phase particles (6) also had a core-shell structure like the dispersed phase particles (1), and the shell layer was Thickness 2.0
It was found that the layer had a sulfonic acid group of μm.

 30 g of the obtained dispersed phase particles (6) 900 (new
70 g of partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.
Mixed and dispersed in the electrorheological fluid composition of the present invention.
Below, this is called fluid composition (6). I got｝.

Example 7 A 2-liter four-neck separable flask equipped with a stirrer and a thermometer was charged with 500 g of hexane, and cooled to 0 ° C. using an ice bath. Next, 500 g of chlorosulfuric acid and 50 g of the polymer crosslinked product (4) obtained in Reference Example 4 were added, followed by stirring for 3 hours to obtain a uniform dispersion. Then remove from the ice bath,
The mixture was stirred at room temperature for 1 hour to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water.
140 ml of a 10% by weight aqueous solution of potassium hydroxide obtained
After neutralizing with, it was sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and is referred to as a dispersed phase particle (7) or less of 76 g of a spherical dispersed phase particle. I got｝.

When the average particle diameter of the obtained dispersed phase particles (7) was measured using a particle size distribution analyzer, it was 5 μm. When the ion exchange capacity of the dispersed phase particles (7) was measured by neutralization titration, it was 3.2 mg equivalent / g. The specific gravity of the dispersed phase particles (7) was measured by using a sedimentation method and found to be 1.30.

When the water content of the dispersed phase particles (7) was measured using a Karl Fischer moisture meter, it was 2.0 parts by weight.

When the cross section of the dispersed phase particles (7) was observed using a scanning electron microscope, the dispersed phase particles (7) also had a core-shell structure like the dispersed phase particles (1), and the shell layer was Thickness 0.6
It was found that the layer had a sulfonic acid group of μm.

 30 g of the obtained dispersed phase particles (7) was
Le KF96-100CS (Shin-Etsu Chemical Co., Ltd.
Reconcil) is mixed and dispersed in 70 g of
Fluid composition (hereinafter referred to as fluid composition (7))
U. I got｝.

Example 8 500 g of 98% by weight concentrated sulfuric acid was charged into one four-neck separable flask equipped with a stirrer and a thermometer, and 50 g of the polymer crosslinked product (3) obtained in Reference Example 3 was added, followed by stirring for 30 minutes. Thus, a uniform dispersion was obtained. Then, the contents of the flask are
The temperature was raised to 80 ° C., and the mixture was heated and stirred at the same temperature for 4 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. The solid obtained is pyridine 12
After neutralizing with g, the mixture was sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and 65 g of spherical dispersed phase particles (hereinafter referred to as dispersed phase particles (8)). I got｝.

When the average particle diameter of the obtained dispersed phase particles (8) was measured using a particle size distribution analyzer, it was 10 μm. The ion exchange capacity of the dispersed phase particles (8) measured by neutralization titration was 2.0 mg equivalent / g. The specific gravity of the dispersed phase particles (8) was measured using a sedimentation method and was found to be 1.17.

The water content of the dispersed phase particles (8) was measured using a Karl Fischer moisture meter, and was 1.9 parts by weight.

When the cross section of the dispersed phase particles (8) was observed using a scanning electron microscope, the dispersed phase particles (8) also had a nucleus-shell structure like the dispersed phase particles (1), and the shell layer was Thickness 0.6
It was found that the layer had a sulfonic acid group of μm.

 30 g of the obtained dispersed phase particles (8) was
Le KF96-20CS (Shin-Etsu Chemical Co., Ltd.
Con oil) mixed and dispersed in 70 g of
Fluid composition (hereinafter referred to as fluid composition (8))
U. I got｝.

Comparative Example 1 500 g of tetrachloroethane was charged into a 3-liter four-neck separable flask equipped with a stirrer and a thermometer, and cooled while stirring. Next, 1 kg of 98% by weight concentrated sulfuric acid and 50 g of the polymer crosslinked product (1) obtained in Reference Example 1 were added, followed by stirring for 30 minutes to obtain a uniform dispersion. Next, the content of the flask was heated to 80 ° C., and heated and stirred at the same temperature for 24 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was
The mixture was poured into water at ℃, filtered and washed with water. The obtained solid is 10
After neutralization with a 200% by weight aqueous solution of sodium hydroxide, the mixture was thoroughly washed with water. Then, using a vacuum dryer, at 80 ℃ 10
After drying for 91 hours, 91 g of spherical dispersed phase particles (hereinafter referred to as comparative dispersed phase particles (1)). I got｝.

When the average particle diameter of the obtained comparative dispersed phase particles (1) was measured using a particle size distribution analyzer, it was 50 μm.
The ion exchange capacity of the comparative dispersed phase particles (1) measured by neutralization titration was 4.5 mg equivalent / g. The specific gravity of the comparative dispersed phase particles (1) was measured using the sedimentation method, and was found to be 1.52.
Met.

The water content in the comparative dispersed phase particles (1) was measured using a Karl Fischer moisture meter, and was 2.7 parts by weight.

When the cross section of the comparative dispersed phase particles (1) was observed at a magnification of 1000 using a scanning electron microscope, an image as shown in FIG. 3 was obtained. As apparent from FIG. 3, the comparative dispersed phase particles (1) had a uniform composition. Further, when the X-ray intensity of the scanning electron microscope (magnification: 1000) was increased and the sulfur element was analyzed on the cross section of the comparative dispersed phase particles (1), an image as shown in FIG. 4 was obtained. . As apparent from FIG. 4, the sulfonic acid groups in the dispersed phase particles were present evenly throughout the particles. From the above results, it was found that the comparative dispersed phase particles (1) had a uniform distribution of sulfonic acid groups throughout the particles as in the case of ordinary ion exchange resins.

 30 g of the obtained comparative dispersed phase particles (1) was
oil KF96-300CS (Shin-Etsu Chemical Co., Ltd.
(Silicone oil) mixed and dispersed in 70g for comparison
Electro-rheological fluid composition ｛Comparative fluid composition
It is called (1). I got｝.

Comparative Example 2 1 kg of 98% by weight concentrated sulfuric acid was charged into a 2 liter four-neck separable flask equipped with a stirrer and a thermometer, and 50 g of the polymer crosslinked product (1) obtained in Reference Example 1 was added, followed by stirring for 30 minutes. Thus, a uniform dispersion was obtained. Then, the contents of the flask are
The temperature was raised to 80 ° C., and the mixture was heated and stirred at the same temperature for 20 minutes to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., and filtered and washed with water. 10% by weight of the obtained solid
After neutralization with 5 ml of an aqueous sodium hydroxide solution, the mixture was sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum dryer, and 49 g of spherical dispersed phase particles (hereinafter referred to as comparative dispersed phase particles (2)). I got｝.

When the average particle size of the obtained comparative dispersed phase particles (2) was measured using a particle size distribution analyzer, it was 50 μm.
When the ion exchange capacity of the comparative dispersed phase particles (2) was measured by neutralization titration, it was 0.1 mg equivalent / g. When the specific gravity of the comparative dispersed phase particle (2) was measured by a sedimentation method, it was 1.06.
Met.

The water content in the comparative dispersed phase particles (2) was measured using a Karl Fischer moisture meter and was found to be 0.7 parts by weight.

When the cross section of the comparative dispersed phase particles (2) was observed using a scanning electron microscope, the comparative dispersed phase particles (2) also had a core-shell structure like the dispersed phase particles (1). The shell layer was a layer having a sulfonic acid group having a thickness of 0.1 μm.

 30 g of the obtained comparative dispersed phase particles (2) was
oil KF96-300CS (Shin-Etsu Chemical Co., Ltd.
(Silicone oil) mixed and dispersed in 70g for comparison
Electro-rheological fluid composition ｛Comparative fluid composition
It is called (2). I got｝.

Comparative Example 3 Sodium polystyrene sulfonate ion-type ion exchange
Amberlite, a replacement resin IR-124 (Tokyo Organic Chemicals)
(Manufactured by Kogyo Co., Ltd.) at 150 ° C for 3 hours, then pulverized and classified.
Below, the amorphous dispersed phase particles
(3) (Ion exchange capacity: 4.4 mg equivalent / g) Get｝
Was.

When the average particle diameter of the obtained comparative dispersed phase particles (3) was measured using a particle size distribution analyzer, it was 50 μm.
The specific gravity of the comparative dispersed phase particle (3) was measured by a sedimentation method and found to be 1.51.

The water content in the comparative dispersed phase particles (3) was measured using a Karl Fischer moisture meter, and was 2.6 parts by weight.

 30 g of the obtained comparative dispersed phase particles (3) was
oil KF96-300CS (Shin-Etsu Chemical Co., Ltd.
(Silicone oil) mixed and dispersed in 70g for comparison
Electro-rheological fluid composition ｛Comparative fluid composition
It is called (3). I got｝.

Example 9 Fluid compositions (1) to (8) and comparative fluid compositions (1) to (3) obtained in Examples 1 to 8 and Comparative examples 1 to 3
Were placed in a test tube, and the degree of sedimentation of the dispersed phase particles after standing at 25 ° C. for 1 day was measured to examine the dispersion stability of the fluid composition. Table 1 shows the results.

Each of the fluid compositions was placed in a double cylindrical rotary viscometer with a coaxial electric field, and the inner / outer cylinder gap was 1.0 mm, and the shear rate was 400.
The shear stress value (initial value) when an external AC electric field of 4000 V / mm (frequency: 60 Hz) was applied under the conditions of s ^-1 and a temperature of 25 ° C., and the current density flowing at that time (initial value) were measured. Further, with an external electric field of 4000 V / mm applied, the viscometer was
The shear stress value (value after 3 days) and current density (value after 3 days) after continuous operation at 3 ° C. for 3 days were measured, and the temporal stability of the fluid composition was examined. Table 1 shows the results.

As is evident from Table 1, the fluid compositions (1) to (8) obtained in the present invention have excellent dispersion stability, and also have a large shear stress even when a relatively weak electric field is applied. Was obtained, and the stability over time was excellent.

On the other hand, in the comparative fluid composition (1), a large shear stress was obtained even when a relatively weak electric field was applied, and the stability over time was excellent, but the dispersion stability was poor. The comparative fluid composition (2) was excellent in dispersion stability, but did not obtain a large shear stress when a relatively weak electric field was applied. In addition, the comparative fluid composition (3) did not exhibit a large shear stress when a relatively weak electric field was applied, and had poor stability over time and dispersion stability.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing the particle structure of the dispersed phase particles (1) obtained in Example 1. FIG. 2 is an electron micrograph showing the particle structure of the dispersed phase particles (1) for sulfur element analysis obtained in Example 1. FIG. 3 is an electron micrograph showing the particle structure of comparative dispersed phase particles (1) obtained in Comparative Example 1. FIG. 4 is an electron micrograph showing the particle structure of comparative dispersed phase particles (1) for sulfur elemental analysis obtained in Comparative Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location C10M 145: 04 151: 02 143: 10) C10N 20:06 40:14 60:10 (72) Invention Person Minoru Kobayashi 1-25-12 Kannondai, Tsukuba City, Ibaraki Prefecture Inside the Tsukuba Research Laboratories of Nippon Shokubai Chemical Industry Co., Ltd. (56) References JP-A-3-162494 (JP, A)

Claims (3)

(57) [Claims] 1. Particles of a polymerized crosslinked product (I) of a monomer mixture (A) containing a vinyl aromatic compound (a) and a polyvinyl compound (b) as essential components and optionally adding another vinyl compound (c). With or without a solvent or a polymerized crosslinked product (I)
To a polymer core having a specific gravity of 1.3 or less obtained by sulfonation in the presence of a non-swelling solvent.
To a polymer particle having a core-shell structure having an average particle diameter in the range of 1.0 to 100 μm having a shell made of a polymer cross-linked product having a sulfonic acid group with a thickness of ~ 5.0 μm, and 100 parts by weight of the particle An electrorheological fluid composition comprising dispersed phase particles by adding 10 parts by weight or less of water to the dispersion phase particles, and dispersing the dispersed phase particles in an insulating dispersion medium. 2. The composition of the monomer mixture (A) has a content of 10.0 to
2. The composition of claim 1, comprising 99.9 mol% of the vinyl aromatic compound (a) and 0.1 to 90.0 mol% of the polyvinyl compound (b).
3. The electrorheological fluid composition according to item 1. 3. The ratio between the dispersed phase particles and the insulating dispersion medium is preferably the former.
The electrorheological fluid composition according to claim 1 or 2, wherein the latter is in the range of 50 to 500 parts by weight per 100 parts by weight.