JPH10158674A - Production of electroviscous fluid composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroviscous fluid composition which generates relatively large shearing stress even upon the application of a relatively weak electric field, is small in the density of an electric current flowing that time and is excellent in the long-term stability of the generated searing stress and electric current density by a production process effective as an industrial process requiring a short reaction time and not requiring powerful agitation. SOLUTION: This composition is prepared by dispersing disperse phase particles comprising a sulfonated polymer in an insulation dispersion medium. When the sulfonated polymer used is prepared by introducing a crosslinked vinyl polymer into a sulfonating agent in the temperature range of 30 to below 90 deg.C, an electroviscous fluid composition which generates relatively large shearing stress even upon the application of a relatively weak electric field, is small in the density of a current flowing that time and is excellent in the long-term stability of the generated shearing stress and current density can be obtained by a production process effective as an industrial process requiring a short reaction time and not requiring powerful agitation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an electrorheological fluid composition. More specifically, an electrorheological fluid composition that generates a large shear stress even when a relatively weak electric field is applied, the current density flowing at that time is small, and the generated shear stress and the current density are excellent in stability over time. The method relates to a method for producing the same.

[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.
A fluid whose rheological or flow properties change to viscoplastic properties by applying an electric field change.In general, the viscosity increases significantly when an external electric field is applied, and the so-called Winslow effect, which induces a large shear stress. Fluid known as Since the Winslow effect has the characteristic of quick response, the electrorheological fluid is applied to actuators for torque transmission such as clutches and brakes, actuators for controlling engine mounts, dampers, valves, etc., and electrorheological fluid inkjet. Attempted.

[0003] Conventionally, as an electrorheological fluid composition, cellulose, starch, soybean casein, silica gel, polystyrene ion exchange resin, crosslinked polyacrylate, etc. in insulating oils such as silicone oil, diphenyl chloride, and trans oil. Are known in which solid particles are dispersed.

[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 a phase has a problem that a practically sufficient shear stress is not induced only by applying a relatively weak electric field.

Further, 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 disperse phase has a large shear force even when a relatively weak electric field is applied. Although a stress is generated, there has been a problem that the current density flowing at that time is large, and the generated shear stress and the current density have poor temporal stability.

On the other hand, an electrorheological fluid composition using, as a disperse phase, a sulfonated polymer particle obtained by sulfonating a polymerized crosslinked product containing styrene and divinylbenzene as main components using sulfuric acid as a sulfonating agent. As a result of studying, the electrorheological fluid composition also generates a large shear stress when a relatively weak electric field is applied, but the current density flowing at that time is large, and the generated shear stress and the current density have poor stability over time. There was a problem.

We have developed a dispersed phase particle comprising a sulfonated polymer obtained by sulfonating a polymerized crosslinked product of a monomer mixture containing a vinyl aromatic compound and a polyvinyl compound as main components and further adding other vinyl compounds as required. Was evaluated in the electrorheological fluid in which was dispersed in an electrically insulating dispersion medium. As a result, it was found that an excellent performance was exhibited when the method was devised in the sulfonation step of the polymer crosslinked product. That is, during the sulfonation of the polymer crosslinked product, a large shear stress is generated even by applying a relatively weak electric field by sulfonating with 150 parts by weight or more of fuming sulfuric acid with respect to 100 parts by weight of the polymer crosslinked product. It has been found that an electrorheological fluid composition having a small current density flowing at that time and having excellent stability over time of generated shear stress and current density can be obtained (Japanese Patent Application No. 2-139873).

However, in the above-mentioned sulfonation method, it is difficult to control the heat of the sulfonation reaction and to control the temperature of the reaction system, and it is necessary to lengthen the reaction time to control the reaction. And that it is not efficient as an industrial process. Further, they have found that there is a problem in that the viscosity of the reaction mixture is increased because stirring is performed at a low temperature when the polymerized crosslinked product is charged, and strong stirring is required, which is industrially disadvantageous.

[0009]

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 provide an electrorheological fluid in which a large shear stress is generated even when a relatively weak electric field is applied, the current density flowing at that time is small, and the generated shear stress and the current density have excellent stability over time. The object of the present invention is to provide a composition by an efficient production method as an industrial process that requires a short reaction time and does not require strong stirring.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the polymerized crosslinked product has been put into a sulfonating agent within a specific temperature range and sulfonated. Even when a relatively weak electric field is applied, a large shear stress is generated, a current density flowing at that time is small, and an electrorheological fluid composition excellent in stability of generated shear stress and current density with time is obtained. In addition, they have found that this production method is an efficient production method as an industrial process that requires a short reaction time and does not require strong stirring, and has completed the present invention.

[0011] That is, an object of the present invention is a composition obtained by dispersing dispersed phase particles comprising a sulfonated polymer in an insulating dispersion medium, wherein the sulfonated polymer is a vinyl polymer crosslinked product. It is achieved by a method for producing an electrorheological fluid composition characterized by being obtained by being charged into a sulfonating agent in a temperature range of 30 ° C. or more and less than 90 ° C. and sulfonated.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments.

[0013] The present invention is a composition obtained by dispersing dispersed phase particles comprising a sulfonated polymer having an aromatic ring substituted with a sulfonic acid group in an insulating dispersion medium. A crosslinked polymer of a vinyl polymer, preferably a polymer crosslinked product of a monomer mixture containing a vinyl aromatic compound and a polyvinyl compound as main components and further adding other vinyl compounds as needed, in a temperature range of 30 ° C. or more and less than 90 ° C. The present invention relates to an electrorheological fluid composition obtained by being charged into a sulfonating agent and sulfonated.

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 a cation released in the presence of a polar solvent such as water. There is no particular limitation.

The sulfonated polymer constituting the dispersed phase particles used in the present invention is a crosslinked vinyl polymer, preferably containing a vinyl aromatic compound and a polyvinyl compound as main components, and further adding other vinyl compounds as needed. Obtained by sulfonating a polymerized crosslinked product of a monomer mixture, and continuously or intermittently introducing a vinylic polymerized crosslinked product into a sulfonating agent having a temperature range of 30 ° C. or more and less than 90 ° C. to perform sulfonation. is required. Conventionally used electrorheological fluid compositions using sulfonated polymer particles as dispersed phase particles, obtained by using sulfuric acid alone as a sulfonating agent, generate large shear stress by applying a relatively weak electric field. However, there was a problem that the current density flowing at that time was large, and the generated shear stress and current density were poor in stability over time. In addition, the polymer crosslinked product 1
The electrorheological fluid composition comprising the sulfonated polymer particles obtained by using 150 parts by weight or more of fuming sulfuric acid as the sulfonating agent as the dispersed phase particles with respect to 00 parts by weight as the dispersed phase particles, Although it is a viscous fluid composition, in the above-mentioned sulfonation method, it is difficult to control the reaction heat of the sulfonation and to control the temperature of the reaction system, and it is necessary to lengthen the reaction time to control the reaction. There is a problem that it is not efficient as an industrial process.In addition, the viscosity of the reaction mixture increases because stirring is performed at a low temperature in preparing the vinyl polymer crosslinked product, and strong stirring is required, which is industrially disadvantageous. There was a problem that there was.
However, when the vinyl polymer crosslinked product is put into a sulfonating agent in a temperature range of 30 ° C. or more and less than 90 ° C. and is sulfonated, the dispersed phase particles which give the above-described electrorheological fluid composition excellent in various performances are provided. Thus, a sulfonated polymer suitable for is obtained.

In the present invention, when the vinyl-based polymer cross-linked product is sulfonated, the vinyl-based polymer cross-linked product is
There is no particular limitation on the sulfonating agent to be used as long as it is put into a sulfonating agent in a temperature range of not less than 90 ° C. and less than 90 ° C. and sulfonates in the temperature range. For example, fuming sulfuric acid, chlorosulfuric acid, sulfur trioxide, Sulfuric acid and the like can be mentioned, and one or more of these can be used,
Particularly, fuming sulfuric acid is preferably used as the sulfonating agent.

When fuming sulfuric acid is used, the proportion of sulfur trioxide in the fuming sulfuric acid is preferably from 10 to 70% by weight. When the proportion of sulfur trioxide is less than 10% by weight and 7
If it exceeds 0% by weight, the prepared electrorheological fluid composition generates a large shear stress by applying a relatively weak electric field, but the current density flowing at that time is large, and the generated shear stress and There may be a problem that the temporal stability of the current density is poor.

The component of the monomer mixture that can be used in the present invention is a vinyl aromatic compound containing 50.0 to 9
Preferably, 9.9 mol% and the polyvinyl compound content are in the range of 0.1 to 50.0 mol%. When the constituent ratio of the vinyl aromatic compound is less than 50.0 mol% or the constituent ratio of the polyvinyl compound exceeds 50.0 mol%, the sulfonation reaction does not easily proceed or the obtained sulfonated polymer particles are obtained. When an electric field is applied to the electrorheological fluid composition using the composition, there may be a problem that a large shear stress cannot be obtained. When the constituent ratio of the vinyl aromatic compound exceeds 99.9 mol% or the constituent ratio of the polyvinyl compound is less than 0.1 mol%, when the vinyl-based polymer crosslinked product obtained by polymerization is sulfonated, There may be a problem that particles adhere to each other.

Examples of the vinyl aromatic compound which can be used in the present invention include vinyl aromatic hydrocarbons such as styrene, vinyl naphthalene, vinyl anthracene and vinyl phenanthrene; methyl styrene, ethyl styrene, propyl styrene, butyl styrene, pentyl Monoalkylstyrene compounds such as styrene and hexylstyrene; dialkyl such as dimethylstyrene, diethylstyrene, dipropylstyrene, methylethylstyrene, methylpropylstyrene, methylhexylstyrene, ethylbutylstyrene, ethylpropylstyrene, ethylhexylstyrene and propylbutylstyrene Styrene compounds: trimethylstyrene, triethylstyrene, tripropylstyrene, methyldiethylstyrene, dimethylethylstyrene, Le ethylpropyl styrene, methyl dipropyl styrene, dimethyl propyl styrene,
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, phenoxystyrene, methoxymethylstyrene, methoxyethylstyrene, methoxypropylstyrene, ethoxymethylstyrene, ethoxyethylstyrene, propyl Oxymethylstyrene, propyloxyethylstyrene, methoxydimethylstyrene, methoxydiethylstyrene, phenoxydimethylstyrene, phenoxydiethylstyrene, methoxychlorostyrene, methoxybromostyrene, vinylmethoxynaphthalene, vinyldimethoxynaphthalene, vinylethoxynaphthalene, vinyldiethoxynaphthalene, Vinylmethoxymethylnaphthalene, vinylmethoxydimethylna Array type, vinyl dimethoxymethyl naphthalene, vinyl methoxy chloronaphthalene, mention may be made of alkoxylation or aryloxy vinyl aromatic compounds such as vinyl dimethoxy-chloronaphthalene may be used one or two or more out of these.

Examples of the polyvinyl compound 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 of the present invention, if necessary, a vinyl compound other than a vinyl aromatic ring compound or a polyvinyl compound can be blended.
It is desirably 0 mol% or less. Examples of such other vinyl compounds include, for example, 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)
Unsaturated amide compounds such as acrylamide or derivatives thereof; unsaturated cyanide compounds such as (meth) acrylonitrile and crotonnitrile; (meth) allyl alcohol;
Unsaturated alcohol compounds such as croton alcohol;
Unsaturated monobasic acids such as (meth) acrylic acid; unsaturated dibasic acids such as maleic acid, fumaric acid and itaconic acid; monohydric alcohols such as monomethyl maleate and monoethyl maleate and unsaturated dibasic Monoester compounds with an acid can be used, and one or more of these can be used.

The shape of the dispersed phase particles used in the present invention is as follows:
It 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 average particle size of the dispersed phase particles used in the present invention is preferably in the range of 0.1 to 100 μm, particularly preferably 1 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 0.1 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, when the average particle diameter of the dispersed phase particles exceeds 100 μm, the shear stress value obtained when a certain electric field is applied to the prepared electrorheological fluid composition becomes irregular, and it is difficult to stabilize. A point may occur.

In the present invention, there is no particular limitation on the method for producing a vinyl polymer crosslinked product used as an intermediate for obtaining a sulfonated polymer, and any known polymerization method may be employed. As the polymerization method, for example, a suspension polymerization method,
Examples of the method include an emulsion polymerization method, a dispersion polymerization method, a solution polymerization method, and a bulk polymerization method.However, a spherical or oval spherical vinyl polymer crosslinked product suitable as dispersed phase particles can be easily obtained. A turbid polymerization method or an emulsion polymerization method is preferred.

When a suspension polymerization method is used as the polymerization method for producing the crosslinked vinyl polymer used in the present invention, the conditions for the polymerization are not particularly limited.

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

Examples of the dispersant for suspension polymerization include polyvinyl alcohol, carboxymethylcellulose, ammonium salts of styrene-maleic anhydride copolymer, bentonite, sodium poly (meth) acrylate, poly (diallylmethylammonium chloride) and the like. Known ones can be used.

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, and caproyl peroxide. Peroxides such as azoisobutyronitrile, azoisobutylamide, 2,2′-azobis (2,
Examples include azo compounds such as 4-dimethylmaleronitrile), azobis (α-dimethylvaleronitrile), and azobis (α-methylbutyronitrile), and one or more of these can be used. The amount used is 0.1 to 1 per 100 parts by weight of the monomer mixture.
0 parts by weight, preferably 1 to 5 parts by weight.

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

The suspension polymerization is usually carried out at a temperature in the range of 50 to 100 ° C. for 2 to 30 hours, preferably about 3 to 10 hours.

As for the operation of suspension polymerization, for example, water and a dispersant are charged, a mixture of monomers in which a polymerization initiator is dissolved is added thereto with stirring, and the particle size is regulated using a disperser or a stirrer. After that, the reaction is carried out at a predetermined temperature in a suspended state.

When an emulsion polymerization method is used to produce the crosslinked vinyl polymer used in the present invention, the conditions for the polymerization are not particularly limited.

As the solvent for the emulsion polymerization, water or the like is usually used.

As the emulsifier for the emulsion polymerization, known emulsifiers 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.

The emulsion polymerization is usually carried out at a temperature in the range of 50 to 100 ° C. for 2 to 40 hours, preferably about 3 to 10 hours.

As the operation of the emulsion polymerization, known methods such as a seed polymerization method, a single charge 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, and the mixture is uniformly dispersed with stirring. Added. 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 crosslinked vinyl polymer used in the present invention may be a substantially non-porous crosslinked polymer called a gel type, or may impart porosity to the crosslinked polymer obtained at the time of polymerization. Known porous forming agents, for example, a swellable organic solvent, a non-swellable organic solvent, a linear polymer soluble in a monomer, or a porous polymer obtained by polymerizing a monomer mixture in the presence of a mixture thereof. It may be a crosslinked polymer.

The particles of the sulfonated polymer constituting the dispersed phase particles used in the present invention can be obtained by sulfonating a vinyl polymer crosslinked product and pulverizing or granulating to an appropriate particle size as required. In addition, when a particulate polymer obtained by a suspension polymerization method or an emulsion polymerization method is used as the vinyl-based polymer crosslinked product, sulfonated polymer particles suitable as the dispersed phase particles in the present invention can be easily obtained by sulfonation. It is preferable because it can be used.

The sulfonation reaction can be carried out without a solvent or in the presence of a solvent that does not swell with respect to the crosslinked vinyl polymer or in the presence of a solvent that swells with respect to the crosslinked vinyl polymer. .

The solvent which does not swell with respect to the crosslinked vinyl polymer may be any solvent which does not swell the crosslinked vinyl polymer and is inert to the sulfonating agent. Examples thereof include aliphatic hydrocarbons such as ligroin.

The solvent which swells with respect to the crosslinked vinyl polymer may be any solvent which swells the crosslinked vinyl polymer and is inactive with respect to the sulfonating agent. Examples of the solvent include ethylene dichloride, trichloroethylene and tetrachloroethylene. Chloroethane, nitrobenzene, propylene chloride, carbon tetrachloride and the like can be mentioned.

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 vinyl polymer.

The sulfonation reaction is carried out at a temperature in the range of 30 to 90 ° C., preferably 40 to 80 ° C. for 0.3 to 100 hours, preferably about 0.5 to 10 hours. The condition is that the vinyl polymer crosslinked product is continuously or intermittently charged into fuming sulfuric acid having a temperature range of 30 ° C. or more and less than 90 ° C.
A method of holding for 0 minute or more can be mentioned.

The particles of the sulfonated polymer obtained by sulfonating the crosslinked vinyl polymer are separated from the sulfonating agent and then treated with a large amount of water in order to remove the acid 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 sulfonated polymer constituting 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 and potassium; Alkaline earth metals such as calcium and calcium; Group IIIA metals such as aluminum; Group IVA metals such as tin and lead; zinc;
Cationic species such as transition metals such as iron, copper, cobalt and nickel, or ammonium, organic quaternary ammonium,
Examples thereof include pyridinium and guadinium, and one or more of these can be used.

The dispersed phase particles used in the present invention are preferably those containing a small amount of water in 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.

However, the water in the dispersed phase particles is
It is preferably 20 parts by weight or less based on 0 parts by weight. 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 ethylnaphthalene, biphenyl, decalin and partially hydrogenated triphenyl; ether compounds such as biphenyl ether; chlorobenzene, dichlorobenzene, trichlorobenzene, bromobenzene, dibromobenzene, chloronaphthalene, dichloronaphthalene, bromonaphthalene, chloro Biphenyl, dichlorobiphenyl, trichlorobiphenyl, bromobiphenyl, chlorodiphenylmethane,
Halogenated hydrocarbons such as dichlorodiphenylmethane, trichlorodiphenylmethane, bromodiphenylmethane, chlorodecane, dichlorodecane, trichlorodecane, bromodecane, chlorododecane, dichlorododecane, and bromododecane; halogenated diphenyl ethers such as chlorodiphenylether, dichlorodiphenylether, trichlorodiphenylether, and bromodiphenylether Compound: Daifoil (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, and the ratio of the dispersed phase particles to the insulating dispersion medium in the composition is as follows.
The amount is preferably 50 to 500 parts by weight, more preferably 100 to 400 parts by weight with respect to 00 parts by weight.
When the amount of the dispersion medium exceeds 500 parts by weight, the shear stress obtained when an electric field is applied to the prepared electrorheological fluid 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, and a polymer thickener may be used to improve the dispersibility of the dispersed phase particles in the dispersion medium, adjust the viscosity of the electrorheological fluid composition, or increase the shear stress. Various additives such as agents can be added to the composition.

[0053]

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.

Example 1 Into a 3 liter four-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, 1.2 liters of water was charged, and Kuraray Poval PVA-205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was added. After adding and dissolving 16.0 g, 300 g of styrene, 20 g of industrial divinylbenzene (a mixture of 55 wt% of divinylbenzene, 35 wt% of ethylstyrene, etc., manufactured by Wako Pure Chemical Industries, Ltd.) and azobis A mixture consisting of 4 g of isobutyronitrile was added. Thereafter, the contents in the flask were dispersed at a stirring speed of 600 rpm, and polymerized at 80 ° C. for 8 hours. The obtained solid was separated by filtration, sufficiently washed with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain a spherical vinyl polymer crosslinked product (hereinafter referred to as polymer crosslinked product (1)). ｝ 285 g was obtained.

A 1-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 500 g of 30% by weight fuming sulfuric acid as a sulfonating agent, and heated to 40 ° C. while stirring. . Next, 50 g of the polymer crosslinked product (1) was added over 1.5 hours while maintaining fuming sulfuric acid at the same temperature to form a uniform dispersion, followed by heating and stirring at the same temperature for 3 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water.

The obtained solid was neutralized with 100 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 dryer, and 98 g of dispersed phase particles composed of a spherical sulfonated polymer is hereinafter referred to as dispersed phase particles (1). I got｝.

The average particle size of the obtained dispersed phase particles (1) was measured with a particle size distribution analyzer (SALD-1 manufactured by Shimadzu Corporation).
000) was 8 μm.

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 5.1 mg equivalent / g, and the elemental analysis method was 5.0 m equivalent / g.
g equivalent / g.

The water content in the dispersed phase particles (1) was measured using a Karl Fischer moisture meter (MKS-3, manufactured by Kyoto Electronics Industry Co., Ltd.).
P), the sulfonated polymer 100
It was 2.1 parts by weight based on 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) was used as Shin-Etsu Silicone Oil KF9.
6-20CS (dimethyl silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed and dispersed in 70 g, and the electrorheological fluid composition of the present invention (hereinafter referred to as fluid composition (1)). I got｝.

Example 2 A 1-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 500 g of 30% by weight fuming sulfuric acid as a sulfonating agent, and heated to 60 ° C. while stirring. The temperature rose. Next, 50 g of the crosslinked polymer (1) obtained in Example 1 was added over 1 hour while maintaining fuming sulfuric acid at the same temperature to form a uniform dispersion.
The mixture was heated and stirred for an hour to perform a sulfonation reaction. afterwards,
The reaction mixture was poured into water at 0 ° C., filtered, and washed with water.

The obtained solid was neutralized with 100 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 dryer, and 96 g of dispersed phase particles composed of spherical sulfonated polymer (hereinafter referred to as dispersed phase particles (2)). I got｝.

The average particle size of the obtained dispersed phase particles (2) was measured by using a particle size distribution analyzer to be 8 μm.

When the ion exchange capacity of the dispersed phase particles (1) was quantified by neutralization titration and elemental analysis, the neutralization titration was 5.2 mg equivalent / g, and the elemental analysis was 5.2 m equivalent / g.
g equivalent / g.

The water content in the dispersed phase particles (2) was measured using a Karl Fischer moisture meter, and was 2.3 parts by weight based on 100 parts by weight of the sulfonated polymer.

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｝.

Example 3 Into a 3 liter four-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, 1.2 liters of water was charged, and Kuraray Povar PVA-205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was added. ) Was added and dissolved, and then 260 g of styrene, 60 g of industrial divinylbenzene (a mixture of 55 wt% of divinylbenzene, 35 wt% of ethylstyrene, etc., manufactured by Wako Pure Chemical Industries, Ltd.) and azobis A mixture consisting of 4 g of isobutyronitrile was added. Thereafter, the contents in the flask were dispersed at a stirring speed of 600 rpm, and polymerized at 80 ° C. for 8 hours. The obtained solid was separated by filtration, sufficiently washed with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain a spherical vinyl-based polymer crosslinked product (hereinafter referred to as polymer crosslinked product (2)). 282 g were obtained.

A 1-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 500 g of 30% by weight fuming sulfuric acid as a sulfonating agent, and heated to 80 ° C. while stirring. . Next, 50 g of the crosslinked polymer (2) was added to 0.5 g of fuming sulfuric acid while maintaining the same temperature.
After adding over a period of time to form a uniform dispersion, the mixture was heated and stirred at the same temperature for 1 hour to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water.

The obtained solid was neutralized with 100 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 dryer, and the dispersed phase particles composed of 102 g of a spherical sulfonated polymer are hereinafter referred to as dispersed phase particles (3). I got｝.

When the average particle size of the obtained dispersed phase particles (3) was measured using a particle size distribution analyzer, it was 7 μm.

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 5.2 mg equivalent / g, and the elemental analysis method was 5.2 m equivalent / g.
g equivalent / g.

When the water content in the dispersed phase particles (3) was measured using a Karl Fischer moisture meter, it was 2.4 parts by weight based on 100 parts by weight of the sulfonated polymer.

30 g of the obtained dispersed phase particles (3) were mixed and dispersed in 70 g of Shin-Etsu silicone oil KF96-20CS (dimethyl silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.), and the electrorheological fluid composition of the present invention was used. Hereinafter, this is referred to as a fluid composition (3). I got｝.

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 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.). ) After adding and dissolving 16.0 g, styrene 220 g, chlorostyrene 70 g,
A mixture consisting of 30 g of industrial divinylbenzene (a mixture of 55 wt% of divinylbenzene, 35 wt% of ethylstyrene, etc., manufactured by Wako Pure Chemical Industries, Ltd.) and 5 g of benzoyl peroxide was added. Thereafter, the contents in the flask were dispersed at a stirring speed of 400 rpm, and polymerized at 80 ° C. for 8 hours. The obtained solid was separated by filtration, sufficiently washed with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain a spherical vinyl-based polymer crosslinked product (hereinafter referred to as polymerized crosslinked product (3)). ｝ 285 g was obtained.

A 1-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 500 g of 30% by weight fuming sulfuric acid as a sulfonating agent and heated to 50 ° C. while stirring. . Next, while maintaining fuming sulfuric acid at the same temperature, 50 g of the crosslinked polymer (3) was added over 1 hour to form a uniform dispersion, and then heated and stirred at the same temperature for 3 hours to perform a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water.

The obtained solid was neutralized with 100 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 96 g of dispersed phase particles composed of a spherical sulfonated polymer is hereinafter referred to as dispersed phase particles (4). I got｝.

The average particle size of the obtained dispersed phase particles (4) was measured with a particle size distribution analyzer to be 8 μm.

The ion exchange capacity of the dispersed phase particles (1) was quantified by a neutralization titration method and an elemental analysis method. As a result, 4.9 mg equivalent / g in the neutralization titration method and 4.9 m in the elemental analysis method.
g equivalent / g.

The water content in the dispersed phase particles (4) was measured using a Karl Fischer moisture meter, and was 2.3 parts by weight based on 100 parts by weight of the sulfonated polymer.

30 g of the obtained dispersed phase particles (4) were mixed and dispersed in 70 g of Shin-Etsu silicone oil KF96-20CS (dimethyl silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.) to prepare the electrorheological fluid composition of the present invention. Hereinafter, this is referred to as a fluid composition (4). I got｝.

Comparative Example 1 A 1-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 500 g of 30% by weight fuming sulfuric acid as a sulfonating agent, and heated to 20 ° C. while stirring. The temperature rose. Next, 50 g of the crosslinked polymer (1) obtained in Example 1 was added over 2 hours while maintaining fuming sulfuric acid at the same temperature to form a uniform dispersion.
The mixture was heated and stirred for an hour to perform a sulfonation reaction. afterwards,
The reaction mixture was poured into water at 0 ° C., filtered, and washed with water.

The obtained solid was neutralized with 100 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 92 g of dispersed phase particles composed of spherical sulfonated polymer (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 by using a particle size distribution analyzer to find that the average particle size was 8 μm.
Met.

The ion exchange capacity of the comparative dispersed phase particles (1) was determined by neutralization titration and elemental analysis. The neutralization titration was 2.3 mg equivalent / g, and the elemental analysis was 2.3 mg equivalent / g.
It was 1 mg equivalent / g.

The water content in the comparative dispersed phase particles (1) was measured using a Karl Fischer moisture meter, and was 1.9 parts by weight based on 100 parts by weight of the sulfonated polymer.
30 g of the obtained comparative dispersed phase particles (1)
00 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.) and mixed and dispersed therein, and the electrorheological fluid composition of the present invention (hereinafter referred to as comparative fluid composition (1)). ｝
I got

Comparative Example 2 350% by weight of fuming sulfuric acid was placed in a 2 liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel.
g and 200 g of tetrachloroethane, and cooled to 0 ° C. using an ice bath with stirring. Then, Example 3
50 g of the polymer crosslinked product (2) obtained in the above was added over 1 hour to obtain a uniform dispersion. Then remove from the greed,
After stirring at room temperature (20 ° C.) for 24 hours, the temperature of the reaction mixture was further raised to 80 ° C., and the mixture was heated and stirred at the same temperature 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.

The obtained solid was neutralized with 100 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 a spherical sulfonated polymer is 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 7 μm.
Met.

The ion exchange capacity of the comparative dispersed phase particles (2) was determined by neutralization titration and elemental analysis. The neutralization titration was 4.9 mg equivalent / g, and the elemental analysis was 4.9 mg equivalent / g.
It was 9 mg equivalent / g.

The water content in the comparative dispersed phase particles (2) was measured using a Karl Fischer moisture meter and found to be 2.1 parts by weight based on 100 parts by weight of the sulfonated polymer.

30 g of the obtained comparative dispersed phase particles (2) were mixed and dispersed in 70 g of Shin-Etsu silicone oil KF96-20CS (dimethyl silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain an electrorheological fluid composition of the present invention. ｛Hereinafter, this is referred to as comparative fluid composition (2). I got｝.

Comparative Example 3 A 2 liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel was charged with 30% by weight fuming sulfuric acid.
g and cooled to 0 ° C. using an ice bath with stirring. Next, the crosslinked polymer (2) 50 obtained in Example 3 was obtained.
g was added over 1 hour to obtain a uniform dispersion. Then, after removing from the lust and stirring at room temperature (20 ° C.) for 15 hours, the temperature of the reaction mixture was further raised to 80 ° C.,
The mixture was heated and stirred at the same temperature for 6 hours to carry out a sulfonation reaction. Thereafter, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water.

The obtained solid was neutralized with 100 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 89 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 by using a particle size distribution analyzer, and found to be 7 μm.
Met.

The ion exchange capacity of the dispersed phase particles (3) was determined by neutralization titration and elemental analysis. The neutralization titration was 5.1 mg equivalent / g, and the elemental analysis was 5.0 m equivalent / g.
g equivalent / g.

The water content in the comparative dispersed phase particles (3) was measured using a Karl Fischer moisture meter, and was 2.3 parts by weight based on 100 parts by weight of the sulfonated polymer.

30 g of the obtained comparative dispersed phase particles (3) were mixed and dispersed in 70 g of Shin-Etsu silicone oil KF96-20CS (dimethyl silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain an electrorheological fluid composition of the present invention. ｛Hereinafter, this is referred to as comparative fluid composition (3). I got｝.

Example 5 Each of the fluid compositions (1) to (4) and the comparative fluid compositions (1) to (3) obtained in Examples 1 to 4 and Comparative Examples 1 to 3 was prepared by applying a coaxial electric field. Put into a double cylindrical rotational viscometer, inner / outer cylinder gap 1.0 mm, shear rate 400 s ^-1 , temperature 25 ° C
Under an external electric field of 4000 V / mm (frequency: 6
(0 Hz) was applied, and the shear stress value (initial value) and the current density flowing at that time (initial value) were measured.

Further, the shear stress value (value after 7 days) and the current density (value after 7 days) after continuous operation of the viscometer at 25 ° C. for 7 days with an external electric field of 4000 V / mm applied were measured. The fluid composition was measured to determine the stability over time.

The results are shown in Table 1. In addition, the reaction time including the charging time in each of Examples (1) to (4) and Comparative Examples (1) to (3) is also shown in 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 has a lower current density at that time. It is particularly preferable that both the shear stress characteristic and the current characteristic are excellent. Therefore, as a parameter for judging superiority by simultaneously evaluating the shear stress characteristic and the current characteristic, a ratio of a shear stress value obtained when a constant electric field is applied to a current density flowing at that time, that is, (shear stress value) / ( Current density) ｛
This value is called 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. Table 1 also shows the calculation results of the Z value.

[0101]

[Table 1]

As is clear from Table 1, the fluid compositions (1) to (4) of the present invention are excellent in the shear stress characteristic that a large shear stress can be obtained even when a relatively weak electric field is applied. It was excellent in current characteristics that the flowing current density was small, and was very excellent in stability of generated shear stress and current density over time. The fluid compositions (1) to (4) obtained in the present invention have a Z value of 1.5 at the initial stage.
As described above, it was found that the composition was an electrorheological fluid composition in which the shear stress characteristics and the current characteristics were balanced. Further, the fluid compositions (1) to (4) obtained in the present invention have a Z value of 1.5 or more even after 7 days, and have excellent stability over time in the balance between shear stress characteristics and power characteristics. It was found to be a viscous fluid composition. The reaction time for sulfonation is 5
The sulfonated polymer was obtained in a very short reaction time of less than 10 hours.

On the other hand, the fluid compositions (1) and (2) of the present invention were obtained from the same polymerized crosslinked product (1) and composed of dispersed phase particles having the same average particle size. ), The obtained shear stress value was small, the current density flowing at that time was large, and the current characteristics were inferior.
In addition, the comparative fluid composition (1) was poor in stability over time of the generated shear stress and current density, and could not be measured after 7 hours. Moreover, the Z value of the comparative fluid composition (1) was 0.8 at the beginning, and the balance between the shear stress characteristics and the current characteristics was worse than that of the fluid composition of the present invention.

In addition, the comparative fluid compositions (2) and (3)
Although a large shear stress was obtained even by applying a relatively weak electric field, the current density flowing at that time was small, and the generated shear stress and the current density were excellent in stability over time. 20 hours or more, which required a very long time as compared with the fluid compositions (1) to (4).

[0105]

According to the present invention, a large shear stress can be obtained even when a relatively weak external electric field is applied, and the stability over time of maintaining the generated shear stress and current density for a long period of time is very excellent. An electro-rheological fluid composition can be obtained and can be effectively used for torque transmission actuators such as clutches and brakes, control actuators for engine mounts, dampers, valves, etc., and electro-rheological fluid ink jets.

The reaction time of the method of the present invention is very short, and is extremely excellent as an industrial process.

Claims (2)

[Claims] 1. A composition comprising dispersed phase particles of a sulfonated polymer dispersed in an insulating dispersion medium, wherein the sulfonated polymer has a cross-linked vinyl polymer at 30 ° C. or higher.
A method for producing an electrorheological fluid composition, which is obtained by charging a sulfonating agent in a temperature range of less than 0 ° C. and sulfonating. 2. The method for producing an electrorheological fluid composition according to claim 1, wherein the sulfonation is performed by using fuming sulfuric acid as a sulfonating agent.