JP2598845B2 - Electrorheological fluid composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to an electrorheological fluid composition. More specifically, an electrorheological fluid composition that generates a large shear stress even by applying a relatively weak electric field, has a small current density flowing at that time, and has excellent stability over time of the generated shear stress and current density. It is about.

[0002]

2. Description of the Related Art An electrorheological fluid is a fluid obtained by dispersing and suspending solid particles in an insulating dispersion medium, for example.
Fluid whose rheological or flow properties change to viscoplastic properties by applying an electric field change. Generally, when an external electric field is applied, the viscosity rises significantly, inducing a large shear stress, the so-called Winslow effect. Is known as a fluid. Since this Windslow effect has a characteristic of quick response, the electrorheological fluid is used for controlling a torque transmitting actuator such as a clutch or a brake, an engine mount, a damper, a controlling actuator for a bubble or the like, an electrorheological fluid. Attempts have been made to apply them to fluid ink jets and the like.

Conventionally, as an electrorheological fluid composition, cellulose, starch, soybean casein, silica gel, polystyrene-based ion exchange resin, polyacrylate cross-linked in insulating oils such as silicone oil, diphenyl chloride, and trans oil. What dispersed solid particles, such as a body, is known.

[0004] However, the electrorheological fluid composition using cellulose, starch or soybean casein as a disperse phase has a problem that the shear stress obtained when an electric field is applied is small. The electrorheological fluid composition used as the disperse phase has a problem that practically sufficient shear stress is not induced only by applying a relatively weak electric field.

An electrorheological fluid composition using an alkali metal salt type ion exchange resin of polystyrene sulfonic acid, which is one of polystyrene ion exchange resins, as a dispersed phase has a large shear stress even when a relatively weak electric field is applied. However, there was a problem that the current density flowing at that time was large, and the generated shear stress and the current density were poor in stability over time.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of conventional electrorheological fluid compositions. Therefore, an object of the present invention is to generate a large shear stress even when a relatively weak electric field is applied, the current density flowing at that time is small, and the electro-viscosities particularly excellent in the temporal stability of the generated shear stress and current density. It is to provide a fluid composition.

[0007]

The present invention is directed to a monomer mixture comprising a vinyl aromatic compound (a) and a polyvinyl compound (b) as essential components and optionally other vinyl compounds (c). A) is polymerized to produce a polymerized crosslinked product (I), and then the dispersed phase particles comprising a sulfonated polymer obtained by sulfonating the aromatic ring present in the polymerized crosslinked product (I) are placed in an insulating dispersion medium. In the polymerization of the monomer mixture (A), the polymerization is carried out at a temperature of less than 80 ° C. until the polymerization rate reaches a range of 30% by weight or more and less than 80% by weight. 99.
The present invention relates to an electrorheological fluid composition characterized in that polymerization is carried out at a temperature of 80 ° C. or more until it reaches 8% by weight or more.

In order to produce the sulfonated polymer used in the present invention, a polymerization reaction of a monomer mixture (A), which is a raw material of a polymer crosslinked product (I) used as an intermediate in obtaining the sulfonated polymer, is carried out by: Polymerization rate is 30% by weight or more 8
It is necessary to carry out the polymerization at a temperature of less than 80 ° C. until it reaches the range of less than 0% by weight, and thereafter to carry out the polymerization at a temperature of 80 ° C. or more until the conversion reaches 99.8% by weight or more.

More preferably, in the polymerization reaction of the monomer mixture (A), the polymerization rate is from 40% by weight to 70% by weight.
It is preferred to carry out the polymerization at a temperature of 50 ° C. or more and less than 80 ° C. until the temperature reaches a range of less than 80 ° C.

In the polymerization reaction of the monomer mixture (A), when the polymerization rate at the end of the polymerization is less than 99.8% by weight,
A problem arises in that shear stability and current density obtained when an electric field is applied to the prepared electrorheological fluid composition have poor stability over time.

In the polymerization reaction of the monomer mixture (A), even when the polymerization rate at the end of the polymerization is 99.8% by weight or more, the polymerization rate is 80% after the polymerization reaction is started in the polymerization of the monomer mixture (A). When the polymerization is carried out at a temperature of less than 80 ° C. until the weight becomes at least 80% by weight and then heated at a temperature of 80 ° C. or more, the shear stress and the current density obtained when an electric field is applied to the prepared electrorheological fluid composition Has a problem that the aging stability is poor.

Further, even when the polymerization rate at the end of the polymerization in the polymerization reaction of the monomer mixture (A) is 99.8% by weight or more, the polymerization rate of the monomer mixture (A) is less than 30% by weight. When heating to a temperature of 80 ° C. or more at a temperature of 80 ° C. or more, there arises a problem that shear stability and current density obtained when an electric field is applied to the prepared electrorheological fluid composition are poor over time. Further, it becomes difficult to control the polymerization, and a problem arises in that a polymer crosslinked product suitable for an electrorheological fluid composition cannot be obtained with good reproducibility.

In the polymerization reaction of the monomer mixture (A), even when the polymerization rate at the end of the polymerization is 99.8% by weight or more, the polymerization rate starts after the polymerization is started in the polymerization of the monomer mixture (A). When the polymerization is carried out at a temperature of less than 80 ° C. from the temperature of less than 80 ° C. to the end of the polymerization without raising the temperature even if it reaches the range of 30% by weight or more and less than 80% by weight, the prepared electrorheological fluid composition is subjected to an electric field. However, there arises a problem that the temporal stability of the shearing stress and the current density obtained when applying the pressure is poor. Further, it takes a long time for polymerization and is not practical.

Further, even if the polymerization rate at the end of the polymerization in the polymerization reaction of the monomer mixture (A) is 99.8% by weight or more, the polymerization of the monomer mixture (A) can be carried out from the start of the polymerization to the end of the polymerization. When the polymerization is carried out at a temperature of 80 ° C. or higher up to 80 ° C., there arises a problem that the shear stress and the current density obtained when an electric field is applied to the prepared electrorheological fluid composition are poor with time. Further, it becomes difficult to control the polymerization, and a problem arises in that a polymer crosslinked product suitable for an electrorheological fluid composition cannot be obtained with good reproducibility.

In the polymerization of the monomer mixture (A) in the present invention, the polymerization is carried out at a temperature of 50 ° C. or more and less than 80 ° C., where the polymerization rate reaches a range of 40% by weight or more and less than 70% by weight. 8 until it reaches 8% by weight or more
It is preferable to carry out the polymerization at a temperature of 0 ° C. or higher. The time when the polymerization temperature is increased after the start of the polymerization is set so that the polymerization rate of the monomer mixture (A) is in the range of 40% by weight or more and less than 70% by weight, so that the above-mentioned electrorheological fluid composition having more excellent temporal stability is provided. Is obtained. Further, it is prepared by conducting the polymerization at a temperature of 50 ° C. or more and less than 80 ° C. until the polymerization rate reaches a range of 40% by weight or more and less than 70% by weight after the initiation of the polymerization, and then raising the temperature to 80 ° C. or more. The shear stability obtained when an electric field is applied to the electrorheological fluid composition and the stability over time of the current density can be further increased,
Another advantage is that the time required to complete the polymerization can be reduced.

In the present invention, it is necessary that the monomer mixture (A) contains a vinyl aromatic compound (a),
Vinyl aromatic compound (a) usable in the present invention
Examples thereof include vinyl aromatic hydrocarbons such as styrene, vinylnaphthalene, vinylanthracene, and vinylphenanthrene; monoalkylstyrene compounds such as methylstyrene, ethylstyrene, propylstyrene, butylstyrene, pentylstyrene, and hexylstyrene; dimethylstyrene, diethyl Styrene, dipropyl styrene, methyl ethyl styrene, methyl propyl styrene,
Dialkylstyrene compounds such as methylhexylstyrene, ethylbutylstyrene, ethylpropylstyrene, ethylhexylstyrene and propylbutylstyrene; trimethylstyrene, triethylstyrene, tripropylstyrene, methyldiethylstyrene, dimethylethylstyrene, methylethylpropylstyrene, methyldipropyl Trialkylstyrene compounds such as styrene, dimethylpropylstyrene, ethyldipropylstyrene and diethylpropylstyrene; vinylmonoalkylnaphthalene compounds such as vinylmethylnaphthalene, vinylethylnaphthalene and vinylpropylnaphthalene; vinyldimethylnaphthalene, vinyldiethylnaphthalene, vinyldivinyl Vinyl dialky such as propylnaphthalene and vinylmethylethylnaphthalene Naphthalene compounds; vinyltrialkylnaphthalene compounds such as vinyltrimethylnaphthalene, vinyltriethylnaphthalene, vinyltripropylnaphthalene, vinylmethyldiethylnaphthalene, vinyldimethylethylnaphthalene, vinylmethylethylpropylnaphthalene; chlorostyrene, bromostyrene, fluorostyrene, chloromethyl Styrene, chloroethylstyrene, chloropropylstyrene, chlorodimethylstyrene, bromomethylstyrene, bromoethylstyrene,
Halogenated vinyl aromatic compounds such as fluoromethylstyrene, fluoroethylstyrene, vinylchloronaphthalene and vinylbromonaphthalene; methoxystyrene, dimethoxystyrene, trimethoxystyrene, ethoxystyrene, diethoxystyrene, triethoxystyrene,
Propyloxystyrene, dipropyloxystyrene,
Phenoxystyrene, methoxymethylstyrene, methoxyethylstyrene, methoxypropylstyrene, ethoxymethylstyrene, ethoxyethylstyrene, propyloxymethylstyrene, propyloxyethylstyrene, methoxydimethylstyrene, methoxydiethylstyrene, phenoxydimethylstyrene, phenoxydiethylstyrene, methoxy Chlorostyrene, methoxybromostyrene, vinylmethoxynaphthalene, vinyldimethoxynaphthalene, vinylethoxynaphthalene, vinyldiethoxynaphthalene, vinylmethoxymethylnaphthalene,
Vinylmethoxydimethylnaphthalene, vinyldimethoxymethylnaphthalene, vinylmethoxychloronaphthalene,
Examples include alkoxylated or aryloxylated vinyl aromatic compounds such as vinyl dimethoxychloronaphthalene, and one or more of these can be used.

In the present invention, it is necessary that the monomer mixture (A) contains the polyvinyl compound (b).
It is preferably in the range of 1 to 20.0 mol%. When the ratio of the polyvinyl compound (b) exceeds 20.0 mol%, sulfonation hardly proceeds, and a large shear stress is obtained when an electric field is applied to an electrorheological fluid composition using the obtained particles. There is a problem that it cannot be performed. Further, when the ratio of the polyvinyl compound (b) is less than 0.1 mol%, a problem may occur that particles adhere to each other when the polymerized crosslinked product obtained by polymerization is sulfonated.

Examples of the polyvinyl compound (b) that can be used in the present invention include divinylbenzene, divinyltoluene, divinylxylene, divinylethylbenzene, divinyldiethylbenzene, divinylpropylbenzene, divinylnaphthalene, trivinylbenzene, trivinyltoluene, Polyvinyl aromatic hydrocarbons such as trivinyl xylene and trivinyl naphthalene; ethylene glycol di (meth) acrylate, diethylene glycol
And polyvinyl aliphatic compounds such as rudi (meth) acrylate, trimethylolpropanetri (meth) acrylate, N, N'-methylenebisacrylamide, diallyl maleate and diallyl adipate.
One or more of these can be used.

In the present invention, the monomer mixture (A) comprises a vinyl aromatic compound (a) and a polyvinyl compound (b) as essential components, and the total amount of the compound (a) and the compound (b) is It is preferable to use 50.0 mol% or more of (A).

The monomer mixture (A) in the present invention may contain, if necessary, a vinyl compound (c) other than the vinyl aromatic compound (a) or the polyvinyl compound (b). It is preferably at most 50 mol%. 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, methylolated (meth) acrylamide and the like Unsaturated amide compounds or derivatives thereof; unsaturated cyanide compounds such as (meth) acrylonitrile and crotonnitrile; unsaturated alcohol compounds such as (meth) allyl alcohol and croton alcohol; and (meth) acrylic acid. Unsaturated monobasic acid; maleic acid Unsaturated dibasic acids such as fumaric acid and itaconic acid; monoester compounds of a monovalent alcohol such as monomethyl maleate and monoethyl maleate with an unsaturated dibasic acid; One or more of them can be used.

The average particle size of the dispersed phase particles used in the present invention is preferably in the range of 1.0 to 50 μm. In the electrorheological fluid composition of the present invention, the shear stress obtained when an electric field is applied to the prepared electrorheological fluid composition tends to decrease as the particle size of the dispersed phase decreases, When the average particle diameter is less than 1.0 μm, a problem may occur 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 50.
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 may cause a problem that stability is difficult.

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

The polymerization method for synthesizing the crosslinked polymer (I) used in the present invention is not particularly limited, and examples thereof include a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method,
Known polymerization methods such as a solution polymerization method and a bulk polymerization method can be used. If the obtained polymerized crosslinked product (I) is sulfonated, a sulfonated polymer having an average particle diameter suitable for the present invention can be easily obtained. The suspension polymerization method is preferred because the polymer crosslinked product (I) having a spherical or oval sphere can be easily obtained.

The conversion can be measured by a direct method such as a method by quantifying unreacted monomers, an evaporation method or a precipitation method, or a method by a change in physical constants accompanying polymerization, that is, a specific gravity measurement method, a viscosity measurement method, a refractive index or a dielectric constant. It can be carried out by a method such as a method based on a rate measurement or a method based on an absorption spectrum. For details of the method for measuring the polymerization rate, see "Experimental Method for Polymer Synthesis" (Takashi Otsu and Masayoshi Kinoshita, published by Kagaku Dojin). It is described in. In the present invention, it is simple and preferable to use an evaporation method which is a direct method.

The specific method of polymerization in the present invention is, for example, a temperature of less than 80 ° C. until the degree of polymerization reaches a range of from 30% by weight to less than 80% by weight, preferably a degree of polymerization of from 40% by weight to less than 70% by weight. 50 to reach the range
The polymerization is carried out at a temperature of not less than 80 ° C. and less than 80 ° C. for about 0.3 to 10 hours.
The polymerization may be carried out at a temperature of not lower than ℃ for about 1 to 20 hours.

When suspension polymerization is used as the polymerization method for obtaining the polymerized crosslinked product (I) in the present invention, for example, water and a dispersant are charged, and the polymerization initiator is dissolved therein under stirring. After the addition of the monomer mixture, the particle size is regulated using a disperser or a stirrer, and then the polymerization is performed under the above-described predetermined polymerization conditions in a suspended state. It is preferably performed under:

Examples of the polymerization initiator for suspension polymerization include benzoyl peroxide, tertiary butyl hydroxy peroxide, cumene peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, tertiary butyl perphthalate, caproyl peroxide and the like. Peroxides: azobisisobutyronitrile, azobisisobutylamide, 2,2′-azobis (2,4-dimethylmaleronitrile), azobis (α
-Dimethylvaleronitrile), azo compounds such as azobis (α-methylbutyronitrile) and the like, and one or more of these can be used. Especially, it is preferable to use benzoyl peroxide and azobisisobutyronitrile.

As a dispersion medium for suspension polymerization, water is usually used.

Examples of the dispersant for suspension polymerization include polyvinyl alcohol, carboxymethyl cellulose, ammonium salts of styrene-maleic anhydride copolymer, bentonite, sodium poly (meth) acrylate, poly (diallylmethyl). Known materials such as ammonium chloride) can be used.

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

The crosslinked polymer (I) used in the present invention comprises:
A substantially non-porous polymer cross-linked product called a gel type may be used, or a known porous forming agent that imparts porosity to the polymer cross-linked product obtained during polymerization, for example, a swellable organic solvent,
A porous polymer crosslinked product obtained by polymerizing a monomer mixture in the presence of a non-swellable organic solvent, a linear polymer soluble in a monomer, or a mixture thereof may be used.

The particles of the sulfonated polymer constituting the dispersed phase particles used in the present invention are obtained by sulfonating the polymerized crosslinked product (I) obtained by the above-mentioned polymerization method, and pulverizing the polymer to an appropriate particle size as necessary. Obtained by granulation. Further, it is preferable to use a particulate polymer obtained by a suspension polymerization method as the polymer crosslinked product (I) because sulfonated polymer particles suitable as dispersed phase particles in the present invention can be easily obtained by sulfonation. .

As the sulfonating agent used for sulfonating the aromatic ring present in the crosslinked polymer (I) in the present invention, a known sulfonating agent may be used, for example, sulfuric acid, fuming sulfuric acid, chloroform. Sulfuric acid and the like can be mentioned, and one or more of these can be used.

When sulfuric acid is used as the main component of the sulfonating agent, the sulfonation is usually performed at a temperature within the range of 60 to 100 ° C. for about 0.3 to 100 hours. Sulfuric acid
It is preferable to use 500 parts by weight or more based on 100 parts by weight of the polymer crosslinked product (I).

When chlorosulfuric acid is used as the main component of the sulfonating agent, sulfonation is usually carried out at a temperature within the range of 0 to 100 ° C. for about 0.3 to 100 hours. The crosslinked product (I) is maintained at a temperature of 70 ° C. or more for 30 minutes or more in the presence of chlorosulfuric acid.
After holding at a temperature range of less than 0 ° C. for 0.3 to 30 hours, there may be further mentioned a case of holding at a temperature of 70 ° C. or more for 30 minutes or more. Above all, a method considering the ease of controlling the sulfonation reaction is preferable. The chlorosulfuric acid is preferably used in a proportion of 500 parts by weight or more based on 100 parts by weight of the polymer crosslinked product (I).

When fuming sulfuric acid is used as the sulfonating agent, sulfonation is usually carried out at a temperature within the range of 0 to 100 ° C. for about 0.3 to 100 hours. (I) in the presence of fuming sulfuric acid at a temperature of 70 ° C. or more for 30 minutes or more, or in the presence of fuming sulfuric acid in a temperature range of -20 ° C. to less than 70 ° C. for 0.3 to 30 minutes. After holding for a period of time, there may be mentioned one that is further held at a temperature of 70 ° C. or more for 30 minutes or more. Above all, a method considering the ease of controlling the sulfonation reaction is preferable. The fuming sulfuric acid is preferably used in a proportion of 150 parts by weight or more based on 100 parts by weight of the polymer crosslinked product (I).

The sulfonation reaction is carried out without a solvent, in the presence of a solvent that does not swell with respect to the polymerized crosslinked product (I), or in the presence of a solvent that is swellable with respect to the polymerized crosslinked product (I). Can be.

The solvent which does not swell with respect to the polymer crosslinked product (I) may be any solvent which does not swell the polymer crosslinked product (I) and is inert to the sulfonating agent, such as hexane and cyclohexane. And aliphatic hydrocarbons such as ligroin.

The solvent capable of swelling with respect to the crosslinked polymer (I) may be any solvent which swells the crosslinked polymer (I) and is inert to the sulfonating agent. For example, ethylene dichloride, trichloroethylene, Examples thereof include tetrachloroethane, nitrobenzene, propylene chloride, and carbon tetrachloride.

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 polymer crosslinked product (I).

In the sulfonation reaction, a transition metal salt such as mercury sulfate or silver sulfate or a pentavalent phosphorus compound such as phosphorus pentoxide can be used in combination with a sulfonating agent. The particles of the sulfonated polymer obtained by sulfonating the polymerized crosslinked product (I) are separated from the sulfonating agent and then sufficiently removed with a large amount of water in order to remove the acid and the like remaining in the particles. It is good to wash. 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 sulfonic acid group referred to in the present invention is a cation which releases a cation in the presence of a polar solvent such as water and turns itself into a sulfonic acid ion, and releases a cation in the presence of a polar solvent such as water. There is no particular limitation.

The cation of the sulfonic acid group present in the sulfonated polymer constituting the dispersed phase particles used in the present invention is not particularly limited. For example, hydrogen; alkali metals such as lithium, sodium and potassium; magnesium; , Calcium, etc., alkaline earth metals; aluminum, etc., Group IIIA metals; tin, lead, etc., Group IVA metals; zinc,
Examples include cationic species such as transition metals such as iron, copper, cobalt and nickel, ammonium, organic quaternary ammonium, pyridinium, guadinium, and the like, and one or more of these can be used.

The dispersed phase particles used in the present invention are preferably those obtained by adding a small amount of water to the above-mentioned sulfonated polymer particles. 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.

In the present invention, the amount of water in the dispersed phase particles is preferably 20 parts by weight or less based on 100 parts by weight of the particles. When water exceeds 20 parts by weight, 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. .

The insulating dispersion medium that can be used in the present invention is not particularly limited. For example, silicone oils such as polydimethylsiloxane and polyphenylmethylsiloxane; liquid paraffin, decane, dodecane, methylnaphthalene, dimethylnaphthalene, Hydrocarbons such as ethyl naphthalene, biphenyl, decalin and partially hydrogenated triphenyl; ether compounds such as diphenyl ether; chlorobenzene, dichlorobenzene, trichlorobenzene, bromobenzene, dibromobenzene, chloronaphthalene, dichloronaphthalene; Bromonaphthalene, chlorobiphenyl, dichlorobiphenyl, trichlorobiphenyl, bromobiphenyl, chlorodiphenylmethane,
Halogenated hydrocarbons such as dichlorodiphenylmethane, trichlorodiphenylmethane, bromodiphenylmethane, chlorodecane, dichlorodecane, trichlorodecane, bromodecane, chlorododecane, dichlorododecane and bromododecane; chlorodiphenyl ether, dichlorodiphenyl ether, trichlorodiphenyl ether Halogenated diphenyl ether compounds such as ter and bromodiphenyl ether; Daifloyl (Daikin Industries, Ltd.)
And demnum (manufactured by Daikin Industries, Ltd.); ester compounds such as dioctyl phthalate, trioctyl trimellitate, and dibutyl sebacate; and one or more of these are used. be able to. Among them, silicone oil and hydrocarbon are preferred.

The electrorheological fluid composition of the present invention is obtained by dispersing the above-mentioned dispersed phase particles in an insulating dispersion medium. The ratio of the dispersed phase particles to the insulating dispersion medium in the composition is 10%.
The latter is preferably in the range of 50 to 500 parts by weight with respect to 0 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. 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.

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

[0049]

The electrorheological fluid composition of the present invention is very excellent in stability over time such that a large shear stress is obtained even when a relatively weak external electric field is applied and the generated shear stress is maintained for a long period of time. Therefore, actuators for transmitting torque such as clutches and brakes, actuators for controlling engine mount dampers, bubbles, etc.
It can be effectively used for ink jet printing, electrorheological fluid ink jet, etc.

[0050]

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

[0051]

Example 1 1.2 liters of water was charged into a 3-liter 4-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, and charged with Kuraray Povar PVA-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, 260 g of styrene and industrial divinylbenzene (a mixture of 55 wt% divinylbenzene, 35 wt% ethylstyrene, etc., manufactured by Wako Pure Chemical Industries, Ltd.) 4
A mixture consisting of 0 g and 10 g of benzoyl peroxide was added. Thereafter, the contents in the flask were dispersed at a stirring speed of 5000 rpm, and polymerized at 75 ° C. for 1 hour. Here, the polymerization rate was 60.2% by weight.

The polymerization rate was measured by weighing about 1 g of the reaction content in an aluminum container, adding about 3 g of a 0.1% by weight solution of hydroquinone in tetrahydrofuran to terminate the polymerization, and then heating with a hot plate. The unreacted monomer was distilled off, and when a constant weight was reached, the residue was weighed and the amount of the produced polymer crosslinked product was calculated. (Hereinafter, the polymerization rate was measured in the same manner.) Further, the polymerization temperature was raised to 95 ° C., and the mixture was heated for 4 hours. The polymerization rate at the end of the reaction is 99.9% by weight
Met. The obtained solid was separated by filtration, sufficiently washed with water, and then 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 (1)). 286 g were obtained.

In a 2-liter four-neck separable flask equipped with a stirrer, a thermometer, and a dropping funnel, 50 g of the crosslinked polymer (1) was charged, and 500 g of 98% by weight concentrated sulfuric acid was added. did. 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 / acetone. The obtained solid was neutralized with 270 ml of a 10% by weight aqueous sodium hydroxide solution, and then sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and the dispersed phase particles composed of 89 g of a spherical sulfonated polymer are hereinafter referred to as dispersed phase particles (1). I got｝.

The average particle diameter of the obtained dispersed phase particles (1) was measured by a particle size distribution analyzer (SALD-1 manufactured by Shimadzu Corporation).
000) was 10 μm.
The ion exchange capacity of the dispersed phase particles (1) was determined by neutralization titration and elemental analysis.
It was 5 mg equivalent / g and 4.5 mg equivalent / g by elemental analysis. The water content in the dispersed phase particles (1) was measured using a Karl Fisher moisture meter (MPS-3P, manufactured by Kyoto Electronics Industry Co., Ltd.), and was 2.5 parts by weight. (Measurement of the average particle diameter, ion exchange capacity, and water content in the following Examples and Comparative Examples was performed in the same manner as in this example.)
30 g of the obtained dispersed phase particles (1) are mixed and dispersed in 70 g of Shin-Etsu Silicone Oil KF96-20CS (dimethyl silicon oil manufactured by Shin-Etsu Chemical Co., Ltd.), and the electrorheological fluid composition of the present invention is hereinafter described. This is a fluid composition (1)
That. I got｝.

[0055]

Example 2 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-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, a mixture consisting of 284 g of styrene, 16 g of industrial divinylbenzene used in Example 1 and 5 g of azobisisobutyronitrile was further added.
Thereafter, the contents in the flask were dispersed at a stirring speed of 8000 rpm, and polymerized at 65 ° C. for 2 hours. Here, the polymerization rate was 42.2% by weight. Further, the polymerization temperature is set at 95 ° C.
And heated for 6 hours. The conversion at the end of the reaction is 9
It was 9.9% by weight. The obtained solid was separated by filtration, sufficiently washed with water, and then 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 (2)). ｝ 291 g were obtained.

A 2-liter four-neck separable flask equipped with a stirrer, thermometer and dropping funnel was charged with 50 g of the crosslinked polymer (2), and the reaction vessel was cooled to 0 ° C. in an ice bath. Thereto was added 500 g of chlorosulfuric acid to obtain a uniform dispersion. After stirring for 12 hours, the ice bath was removed,
The mixture was heated and stirred at 80 ° C. for 3 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water / acetone. After the obtained solid was neutralized with 280 ml of a 10% by weight aqueous sodium hydroxide solution,
Washed thoroughly with water. Then, using a vacuum dryer, 8
After drying at 0 ° C. for 10 hours, the dispersed phase particles composed of 102 g of a spherical sulfonated polymer (hereinafter referred to as dispersed phase particles (2)). I got｝.

When the average particle size of the obtained dispersed phase particles (2) was measured using a particle size distribution analyzer, it was 5 μm. When the ion exchange capacity of the dispersed phase particles (2) was quantified by a neutralization titration method and an elemental analysis method, it was 5.3 mg equivalent / g by the neutralization titration method and 5.4 mg equivalent / g by the elemental analysis method. The water content in the dispersed phase particles (2) was measured using a Karl Fisher moisture meter and found to be 2.4 parts by weight.

30 g of the obtained dispersed phase particles (2) were mixed and dispersed in 70 g of THERM S900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.) to obtain an electrorheological fluid composition of the present invention. ｛Hereinafter, this is referred to as a fluid composition (2). I got｝.

[0059]

Example 3 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-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolving, 140 g of styrene, 133 g of methoxystyrene, 27 g of the same industrial divinylbenzene as used in Example 1, and 5 g of azobisisobutyronitrile were used.
Was added. Then, using a dispersing machine, 700
The contents in the flask were dispersed at a stirring speed of rpm, and 7
Polymerization was carried out at 0 ° C. for 1 hour. Here, the polymerization rate was 67.3% by weight. Further, the polymerization temperature was raised to 90 ° C., and the mixture was heated for 6 hours. The polymerization rate at the end of the reaction was 99.8% by weight. 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 a spherical polymer crosslinked product (hereinafter referred to as polymer crosslinked product (3)). $ 289
g was obtained.

A 2-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 50 g of the crosslinked polymer (3) and 500 g of 98% by weight concentrated sulfuric acid. The sulfonation reaction was performed for hours. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water / acetone. The obtained solid is
After neutralization with 240 ml of aqueous solution of potassium hydroxide by weight,
Washed thoroughly with water. Then, using a vacuum dryer, 8
After drying at 0 ° C. for 10 hours, 98 g of dispersed phase particles composed of spherical sulfonated polymer (hereinafter referred to as dispersed phase particles (3))
That. I got｝.

The average particle size of the obtained dispersed phase particles (3) was measured using a particle size distribution analyzer, and was found to be 25 μm. When the ion exchange capacity of the dispersed phase particles (3) was determined by a neutralization titration method and an elemental analysis method, it was 4.4 mg equivalent / g by the neutralization titration method and 4.2 mg equivalent / g by the elemental analysis method. The water content in the dispersed phase particles (3) was measured using a Karl Fischer moisture meter and found to be 2.4 parts by weight.

30 g of the obtained dispersed phase particles (3) were mixed and dispersed in 70 g of THERM S900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.) to obtain an electrorheological fluid composition of the present invention. ｛Hereinafter, this is referred to as a fluid composition (3). I got｝.

[0063]

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-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, a mixture of 140 g of styrene, 133 g of chlorostyrene, 27 g of industrial divinylbenzene used in Example 1 and 10 g of benzoyl peroxide was further added. Then, the contents in the flask were dispersed at a stirring speed of 5000 rpm using a disperser,
Polymerized for hours. Here, the polymerization rate was 51.2% by weight. Further, the polymerization temperature was raised to 100 ° C., and the mixture was heated for 6 hours. The conversion at the end of the reaction was 99.9% by weight. The obtained solid was separated by filtration, sufficiently washed with water, and then 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)). 286 g were obtained.

A 2-liter four-neck separable flask equipped with a stirrer, thermometer and dropping funnel was charged with 50 g of the polymerized crosslinked product (4), and the reaction vessel was cooled to 0 ° C. in an ice bath. 500 g of fuming sulfuric acid of 25% by weight was added thereto to obtain a uniform dispersion. After stirring for 12 hours, the ice bath was removed, and the mixture was heated and stirred at 80 ° C. for 5 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water / acetone. The obtained solid was neutralized with 140 ml of a 10% by weight aqueous solution of lithium hydroxide, and then sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and the dispersed phase particles composed of 91 g of a spherical sulfonated polymer are hereinafter referred to as dispersed phase particles (4). I got｝.

When the average particle size 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 quantified by neutralization titration and elemental analysis, it was 5.5 mg equivalent / g by neutralization titration and 5.6 mg equivalent / g by elemental analysis. The water content in the dispersed phase particles (4) was measured using a Karl Fisher moisture meter and found to be 3.2 parts by weight.

30 g of the obtained dispersed phase particles (4) are mixed and dispersed in 70 g of bromobenzene, and the electrorheological fluid composition of the present invention (hereinafter referred to as fluid composition (4)). ｝
I got

[0067]

Example 5 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-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, a mixture consisting of 280 g of styrene, 20 g of industrial divinylbenzene used in Example 1 and 10 g of benzoyl peroxide was further added. Thereafter, the content in the flask was dispersed at a stirring speed of 8000 rpm using a disperser, and polymerized at 65 ° C. for 2 hours. Here, the polymerization rate was 41.3% by weight. Further, the polymerization temperature is set to 95.
C. and heated for 6 hours. The conversion at the end of the reaction is 9
It was 9.9% by weight. 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 a spherical polymer crosslinked product (hereinafter referred to as polymer crosslinked product (5)). ｝ 291 g were obtained.

A 2-liter four-neck separable flask equipped with a stirrer, thermometer and dropping funnel was charged with 50 g of the crosslinked polymer (5) and 250 g of tetrachloroethane, and the reaction vessel was cooled to 0 ° C. in an ice bath. did. Thereto was added 500 g of chlorosulfuric acid to obtain a uniform dispersion. As it is 12
After stirring for an hour, the ice bath was removed, and the mixture was heated and stirred at 80 ° C. for 5 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water / acetone. The obtained solid was neutralized with 50 g of pyridine, and then 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 (5) hereinafter. 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. When the ion exchange capacity of the dispersed phase particles (5) was quantified by neutralization titration and elemental analysis, it was 4.0 mg equivalent / g by neutralization titration and 4.0 mg equivalent / g by elemental analysis. The water content in the dispersed phase particles (5) was measured using a Karl Fisher moisture meter and found to be 2.4 parts by weight.

30 g of the obtained dispersed phase particles (5) are mixed and dispersed in 70 g of liquid paraffin, and the electrorheological fluid composition of the present invention (hereinafter referred to as fluid composition (5)). ｝
I got

[0071]

Comparative Example 1 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-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, a mixture consisting of 260 g of styrene, 40 g of the same industrial-use divinylbenzene used in Example 1 and 10 g of benzoyl peroxide was further added. afterwards,
The contents in the flask were dispersed at a stirring speed of 5000 rpm, and polymerized at 75 ° C. for 3 hours. Here, the polymerization rate is 9
It was 3.2% by weight. Further, the polymerization temperature was raised to 95 ° C., and the mixture was heated for 5 hours. The polymerization rate at the end of the reaction is 99.6
% By weight. The obtained solid was separated by filtration, sufficiently washed with water, and then dried at 80 ° C. for 12 hours using a hot air drier.
Spherical polymer crosslinked product (hereinafter referred to as comparative polymer crosslinked product (1))
That. ｝ 283 g was obtained.

In a 2-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel, 50 g of the comparative polymer crosslinked product (1) was charged, and 500 g of 98% by weight concentrated sulfuric acid was added. And The temperature of the reaction mixture to 80 ° C.
Then, 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 / acetone. The obtained solid was neutralized with 270 ml of a 10% by weight aqueous sodium hydroxide solution, and then sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and 87 g of dispersed phase particles composed of a spherical sulfonated polymer is hereinafter referred to as comparative dispersed phase particles (1). I got｝.

The average particle size of the obtained comparative dispersed phase particles (1) was measured using a particle size distribution analyzer.
m. When the ion exchange capacity of the dispersed phase particles (1) was determined by a neutralization titration method and an elemental analysis method, the neutralization titration method was 4.5 mg equivalent / g, and the elemental analysis method was 4.5 m.
g equivalent / g. The water content of the dispersed phase particles (1) was measured using a Karl Fischer moisture meter.
It was 5 parts by weight.

30 g of the obtained comparative dispersed phase particles (1) were mixed with 70 g of Shin-Etsu Silicone Oil KF96-20CS (dimethyl silicon oil manufactured by Shin-Etsu Chemical Co., Ltd.).
An electrorheological fluid composition for comparison, which is hereinafter referred to as a comparative fluid composition (1). I got｝.

[0075]

Comparative Example 2 Water (1.2 liter) 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-205 (manufactured by K.K.).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, a mixture consisting of 260 g of styrene, 40 g of the same industrial-use divinylbenzene used in Example 1 and 10 g of benzoyl peroxide was further added. afterwards,
The contents in the flask were dispersed at a stirring speed of 5000 rpm, and polymerized at 65 ° C. for 2 hours. Here, the polymerization rate is 5
It was 3.2% by weight. Further, the polymerization temperature was raised to 95 ° C., and the mixture was heated for 2 hours. The polymerization rate at the end of the reaction is 99.6
% By weight. The obtained solid was separated by filtration, sufficiently washed with water, and then dried at 80 ° C. for 12 hours using a hot air drier.
Spherical polymer crosslinked product (hereinafter referred to as comparative polymer crosslinked product (2))
That. ｝ 293 g were obtained.

A 2-liter four-neck separable flask equipped with a stirrer, thermometer and dropping funnel was charged with 50 g of the comparative polymer crosslinked product (2), and 500 g of 98% by weight concentrated sulfuric acid was added. And The temperature of the reaction mixture to 80 ° C.
Then, 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 / acetone. The obtained solid was neutralized with 270 ml of a 10% by weight aqueous sodium hydroxide solution, and then sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and 87 g of dispersed phase particles composed of a spherical sulfonated polymer is hereinafter referred to as comparative dispersed phase particles (2). I got｝.

The average particle size of the obtained comparative dispersed phase particles (1) was measured using a particle size distribution analyzer.
m. When the ion exchange capacity of the dispersed phase particles (2) was determined by a neutralization titration method and an elemental analysis method, the neutralization titration method was 4.5 mg equivalent / g, and the elemental analysis method was 4.5 m.
g equivalent / g. The water content in the dispersed phase particles (2) was measured using a Karl Fischer moisture meter.
It was 5 parts by weight.

30 g of the obtained comparative dispersed phase particles (2) were mixed with 70 g of Shin-Etsu Silicone Oil KF96-20CS (dimethyl silicon oil manufactured by Shin-Etsu Chemical Co., Ltd.).
An electrorheological fluid composition for comparison, which is hereinafter referred to as a comparative fluid composition (2). I got｝.

[0079]

Comparative Example 3 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-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, a mixture consisting of 284 g of styrene, 16 g of industrial divinylbenzene used in Example 1 and 5 g of azobisisobutyronitrile was further added.
Thereafter, the contents in the flask were dispersed at a stirring speed of 8000 rpm, and polymerized at 70 ° C. for 3 hours. Here, the polymerization rate was 90.2% by weight. Further, the polymerization temperature is set at 95 ° C.
And heated for 5 hours. The conversion at the end of the reaction is 9
It was 9.9% by weight. The obtained solid was separated by filtration, washed sufficiently 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 comparative polymer crosslinked product (3)). 288 g were obtained.

A 2-liter four-neck separable flask equipped with a stirrer, thermometer and dropping funnel was charged with 50 g of the comparative polymer crosslinked product (3), and 500 g of 98% by weight concentrated sulfuric acid was added. And The temperature of the reaction mixture to 80 ° C.
Then, 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 / acetone. The obtained solid was neutralized with 280 ml of a 10% by weight aqueous sodium hydroxide solution, and then sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and 87 g of dispersed phase particles composed of a spherical sulfonated polymer (hereinafter referred to as comparative dispersed phase particles (3)). I got｝.

The average particle size of the obtained comparative dispersed phase particles (3) was measured using a particle size distribution analyzer.
Met. When the ion exchange capacity of the comparative dispersed phase particles (3) was determined by a neutralization titration method and an elemental analysis method, the neutralization titration method was 4.6 mg equivalent / g, and the elemental analysis method was 4.5.
mg equivalent / g. The water content in the comparative dispersed phase particles (3) was measured using a Karl Fisher moisture meter, and was 2.5 parts by weight.

30 g of the obtained comparative dispersed phase particles (3) were mixed and dispersed in 70 g of THERM S900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.), and an electrorheological fluid composition for comparison was prepared. The following is a comparative fluid composition (3)
That. I got｝.

[0083]

Comparative 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-205 (trade name).
Add 16.0 g of Kuraray's polyvinyl alcohol)
After dissolution, a mixture consisting of 260 g of styrene, 40 g of the same industrial-use divinylbenzene used in Example 1 and 10 g of benzoyl peroxide was further added. afterwards,
The contents in the flask were dispersed at a stirring speed of 700 rpm and polymerized at 70 ° C. for 1 hour. Here, the polymerization rate is 28.
7% by weight. Further, the polymerization temperature was raised to 95 ° C., and the mixture was heated for 5 hours. The polymerization rate at the end of the reaction was 99.9% by weight. 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 a spherical polymer crosslinked product (hereinafter referred to as comparative polymer crosslinked product (4)). 286 g were obtained.

A 2-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 50 g of the comparative polymer crosslinked product (4) and 250 g of tetrachloroethane, and the reaction vessel was cooled to 0 ° C. in an ice bath. Cool. Thereto was added 500 g of chlorosulfuric acid to obtain a uniform dispersion. 1 as it is
After stirring for 2 hours, the ice bath was removed, and the mixture was heated and stirred at 80 ° C. for 5 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water / acetone. The obtained solid was neutralized with 270 ml of a 10% by weight aqueous sodium hydroxide solution, and then sufficiently washed with water. Next, it is dried at 80 ° C. for 10 hours using a vacuum drier, and 98 g of dispersed phase particles composed of spherical sulfonated polymer (hereinafter referred to as comparative dispersed phase particles (4)). I got｝.

The average particle size of the obtained comparative dispersed phase particles (4) was measured using a particle size distribution analyzer.
m. When the ion exchange capacity of the comparative dispersed phase particles (4) was quantified by neutralization titration and elemental analysis, the neutralization titration was 5.0 mg equivalent / g, and the elemental analysis was 5.0 mg equivalent / g.
It was 1 mg equivalent / g. The water content in the comparative dispersed phase particles (4) was measured using a Karl Fisher moisture meter, and was 2.5 parts by weight.

30 g of the obtained comparative dispersed phase particles (4) were mixed with 70 g of Shin-Etsu Silicone Oil KF96-20CS (dimethyl silicon oil manufactured by Shin-Etsu Chemical Co., Ltd.).
An electrorheological fluid composition for comparison, which is hereinafter referred to as a comparative fluid composition (4). I got｝.

[0087]

Comparative Example 5 Amberlite IR-124 which is a sodium polystyrene sulfonate ion-type ion exchange resin
(Tokyo Organic Chemical Industry Co., Ltd.) was dried at 150 ° C. for 3 hours, pulverized and classified, and the amorphous dispersed phase particles for comparison were hereinafter referred to as comparative dispersed phase particles (5). I got｝.

The average particle size of the comparative dispersed phase particles (5) was measured using a particle size distribution analyzer and found to be 10 μm. When the ion exchange capacity of the comparative dispersed phase particles (5) was quantified by neutralization titration and elemental analysis, it was 4.4 mg equivalent / g by neutralization titration and 4.4 mg equivalent / g by elemental analysis. . The water content in the comparative dispersed phase particles (5) was measured using a Karl Fisher moisture meter.
It was 5 parts by weight.

30 g of the obtained comparative dispersed phase particles (5) were mixed and dispersed in 70 g of Shin-Etsu Silicone Oil KF96-20CS, and a comparative electrorheological fluid composition (hereinafter referred to as comparative fluid composition (5)) . I got｝.

[0090]

Example 6 Each of the fluid compositions (1) to (5) and the comparative fluid compositions (1) to (5) obtained in Examples 1 to 5 and Comparative Examples 1 to 5 was rotated with a coaxial electric field. Put in the viscometer,
Shear stress value (initial value) when an external AC electric field of 4000 V / mm (frequency: 60 Hz) is applied under the conditions of an inner / outer cylinder gap of 1.0 mm, a shear rate of 400 s- ¹ and a temperature of 25 ° C.
The current density (initial value) flowing at that time was measured.

Further, the shear stress value (after 14 days) and the current density (after 14 days) after the viscometer was continuously operated at 25 ° C. for 14 days in the state of applying an external electric field of 4000 V / mm were measured. The fluid composition was measured to determine the stability over time.

The results are shown in Table 1.

[0093]

[Table 1]

The electrorheological fluid has a higher shear stress value obtained when a relatively weak electric field is applied, and has a higher shear stress value, and a lower current density at the time. It is particularly preferable that both the shear stress characteristic and the current characteristic are excellent. Therefore, as a parameter for judging the superiority by simultaneously evaluating the shear stress characteristic and the current characteristic, the ratio of the shear stress value obtained when a constant electric field is applied to the current density flowing at that time, that is, (shear stress value) / (Current density) ｛This value is hereinafter referred to as a Z value. ｝ Is effective. That is, an electrorheological fluid composition having both excellent shear stress characteristics and current characteristics has a large Z value.

The fluid compositions (1) to (5) and the comparative fluid compositions (1) to (5) were determined from the shear stress value and the current density observed when an electric field of 4000 V / mm was applied. The initial value of the Z value of each fluid composition and 1
The values after 4 days are shown in Table 1.

As is clear from Table 1, the fluid compositions (1) to (5) of the present invention can obtain a large shear stress even when a relatively weak electric field is applied, and the current density flowing at that time is small. The current characteristics were excellent and the shear stress and the current density generated over time were very excellent in stability. In addition, the fluid compositions (1) to (5) of the present invention have an initial Z value of 1.9 or more, and even after 14 days,
The value was 1.9 or more, indicating that the composition was an electrorheological fluid having excellent stability over time in the balance between shear stress characteristics and current characteristics.

On the other hand, the comparative fluid compositions (1) to (4)
It was inferior in stability over time of shear stress and current density.
Further, in the comparative fluid composition (5), a large shear stress was not obtained by applying a relatively weak electric field, the current density flowing at that time was large, and the stability over time was poor. The Z values of the comparative fluid compositions (1) to (4) were 1.6 or more in the initial stage, but the stability over time was poorer than the fluid composition of the present invention. Comparative fluid composition (5) had an initial Z value of 0.2, and the balance between shear stress characteristics and current characteristics was poorer than the fluid composition of the present invention.

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C10N 30:00 40:04 40:08 40:14 60:10 70:00 Examiner Michie Hirayama (56) Reference Document JP-A-3-215597 (JP, A) JP-A-4-36389 (JP, A)

Claims (2)

(57) [Claims] 1. A polymerized crosslinked product (A) obtained by polymerizing a monomer mixture (A) containing a vinyl aromatic compound (a) and a polyvinyl compound (b) as essential components and further adding other vinyl compounds (c) as necessary. A composition obtained by dispersing dispersed phase particles comprising a sulfonated polymer obtained by synthesizing I) and then sulfonating an aromatic ring present in the polymerized crosslinked product (I) in an insulating dispersion medium, In the polymerization of the monomer mixture (A), polymerization is carried out at a temperature of less than 80 ° C. until the conversion reaches a range of 30% by weight or more and less than 80% by weight. An electrorheological fluid composition characterized in that polymerization is carried out at a temperature of not less than ° C. 2. In the polymerization of the monomer mixture (A),
Polymerization is carried out at a temperature of 50 ° C. or more and less than 80 ° C. until the conversion reaches a range of 40% by weight or more and less than 70% by weight. The electrorheological fluid composition according to claim 1, wherein the composition is performed.