JPH0496997A - Electric viscous fluid - Google Patents

Abstract

PURPOSE:To provide the title fluid excellent in current characteristics, dispersion stability and fluidity, useful for clutches, etc., comprising each specific disperse phase, dispersion medium and polymeric additive prepared by polymerizing a vinyl monomer in the presence of a polymer carrying at its one end vinyl group. CONSTITUTION:The objective fluid comprising (A) 100 pts.wt. of a disperse phase consisting of organic polymer granules with cation exchange ability such as a sulfonic acid group-contg. polystyrene-based polymer ones, (B) pref. 50-500 pts.wt. of a dispersion medium consisting of an electrical insulating fluid mainly of a hydrocarbon compound such as dodecane, and (C) pref. 0.1-60 pts.wt. of a polymeric additive prepared by polymerizing a vinyl monomer such as styrene in the presence of a polymer carrying at its one end vinyl group, made up of structural unit of formula I (R<1> and R<2> are each H or methyl) and/or formula II (R<3> is H or methyl; X is aromatic hydrocarbon or substituent having O or N).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to electrorheological fluids. More specifically, it has excellent current characteristics in that it generates a large shear path force even when a relatively weak electric field is applied, and the current density that flows at that time is small, and the stability of the shear path force and current density over time without being generated. This refers to an electrorheological fluid that has excellent dispersion stability (ability to maintain an electrorheological fluid in a uniform state for a long time without causing the dispersed phase to settle or float) when no electric field is applied. be.

(Prior art) An electrorheological fluid is a fluid obtained by dispersing/suspending solid particles in an insulating dispersion medium. It is generally known as a fluid that exhibits the so-called Winslow effect, in which the viscosity increases significantly and a large shear path force is induced when an external electric field is applied.

This Winslow effect has the characteristic of quick response, so electrorheological fluids can be used in clutches, tampers, brakes, etc.
Applications to shock absorbers, actuators, valves, etc. are being attempted.

Conventionally, known electrorheological fluids include solid particles such as cellulose, starch, soybean casein, and silica gel dispersed in insulating oil such as silicone oil, diphenyl chloride, and transformer oil. However, those using cellulose, starch, soybean casein, silica gel, etc.
There was a problem in that the shear road force generated was small.

On the other hand, as an electrorheological fluid that generates high shear path force,
For example, when powder of ion exchange resin is suspended in higher alkyl ester of aromatic carboxylic acid,
278>, and a composition comprising a crystalline substance, a dielectric liquid, and an additive that conducts current along only one of the three crystals (Japanese Patent Laid-Open No. 1-170693).

However, these electrorheological fluids have a G
The current density is relatively large and the current characteristics are poor, and the dispersed phase easily separates when no electric field is applied, and conversely, when the concentration of the dispersed phase is increased to prevent separation, the fluidity is poor. It had the problem of becoming.

In order to solve the problems of separation of dispersed phases and fluidity, methods of adding additives such as dispersion stabilizers to electrorheological fluids have been proposed. However, many of the surfactants and stearic acid additives known as ordinary dispersion stabilizers have poor solubility in dispersion media consisting of insulating liquids mainly composed of hydrocarbon compounds. , it was virtually impossible to add them to these systems. Furthermore, even with substances that are soluble in the dispersion medium (such as ricinoleic acid and oleic acid), it has not been possible to improve the dispersion stability to the extent that it does not pose a practical problem.

In addition, in an electrorheological fluid having silica gel as a dispersed phase, a polymer of an N- and/or OH-containing compound and an alkyl group-containing compound having 4 to 24 carbon atoms such as higher alkyl (meth)acrylate is used as a dispersion stabilizer. Showa 6l-259
752) and modified silicone oil (JP-A-2-2663)
3> has been proposed.

However, 1. Although such dispersion stabilizers are effective for electrorheological fluids with a silica gel dispersed phase,
This method has not been sufficient to improve the dispersion stability of electrorheological fluids containing organic polymers such as sulfonic acid group-containing polystyrene ion exchange resins as a dispersed phase. Moreover, the electrorheological fluids described in these publications had the problem that the shear path force generated was insufficient.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems that conventional electrorheological fluids have.

The object of the present invention is to generate a large shear stress even by applying a relatively weak electric field, and to have excellent current characteristics such that the current density flowing at that time is small, and to reduce the shear stress and current density without being generated. Excellent stability over time,
Furthermore, it is an object of the present invention to provide an electrorheological fluid that has a low viscosity when no electric field is applied, has excellent fluidity, and has particularly excellent dispersion stability such that the dispersed phase does not easily settle or float.

(Means and effects for solving the problem) The present invention provides a dispersed phase made of organic polymer particles having cation exchange ability, a dispersion medium made of an insulating liquid mainly composed of a hydrocarbon compound, and a polymer additive. A polymer (II) obtained by polymerizing a vinyl monomer in the presence of a polymer (I>) having a vinyl group at one end as a polymer additive. The present invention relates to an electrorheological fluid characterized by using.

When obtaining the polymer (If) which is effective as a polymer additive contained in the electrorheological fluid of the present invention, the polymer (I) having a vinyl group at one end used as a raw material is used as the main component of the main chain. The structural unit (A) represented by the general formula % formula % (wherein R1 and R2 are each independently hydrogen or methyl group) and/or the general formula (wherein R3 is hydrogen or methyl group) and X is an aromatic hydrocarbon group or a substituent having a nitrogen atom or an oxygen atom.) Such a structural unit (A) preferably has a structural unit (B) represented by and/or the structural unit (B) is contained as a main component in the main chain of the polymer (1), thereby increasing the effect when the resulting polymer (II) is used as a polymer additive for electrorheological fluids. more effectively. That is, if the structural unit (A) and/or the structural unit (B) are not contained in the polymer (I), an electrorheological fluid with excellent current characteristics and dispersion stability may not be obtained. .

Compounds that provide the structural unit (A> that is the main component of the polymer (I) include, for example, alkylene oxides such as ethylene oxide, propylene oxide, and 2,3-butylene oxide; ethylene glycol, propylene glycol, and 2,3-butylene. Glycols such as glycol can be mentioned, and one kind or two or more kinds thereof can be used.

The substituent X in the structural unit (B) which is the main component of the main chain of the polymer (I) needs to be an aromatic hydrocarbon group or a substituent having a nitrogen atom or an oxygen atom. Examples of aromatic hydrocarbon groups include aryl groups such as phenyl, naphthyl, anthryl, and phenanthryl groups; methylphenyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, and hexylphenyl groups. Dialkyl aryl groups such as monoalkylaryl group, dimethylphenyl group, methylethylphenyl group, methylpropylphenyl group, diethylphenyl group, ethylpropylphenyl group, dipropylphenyl group;
Examples include trialkylaryl groups such as trimethylphenyl group, dimethylethylphenyl group, methyldiethylphenyl group, triethylphenyl group, and tripropylphenyl group. Further, examples of the substituent having a nitrogen atom or an oxygen atom include a cyano group: 2-pyridyl group,
4-pyridyl group; 2-pyrrolidone-1-yl group; aminoaryl group such as niaminomethylphenyl group or dimethylaminomethylphenyl group; alkoxyaryl group such as methoxyphenyl group or methoxymethylphenyl group; methoxycarbonyl group or ethoxycarbonyl group; , propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, octyloxycarbonyl group, decyloxycarbonyl group, dodecyloxycarbonyl group; alkyloxycarbonyl group; hydroxyethoxycarbonyl group, aminoethyloxycarbonyl group ,N.

Substituted alkyloxycarbonyl group such as N-dimethylamine ethyloxycarbonyl group: N~methylaminocarbonyl group, alkylaminocarbonyl group such as N,N-dimethylaminocarbonyl group: carbonyloxy group such as acetoxy group, benzoyloxy group; Examples include alkoxy groups such as methoxy, ethoxy, and propoxy groups.

Examples of compounds providing the structural unit (B) which is the main component of the polymer (I>) include styrene, vinylnaphthalene, vinylanthracene, vinylphenanthrene, vinyltoluene, ethylstyrene, propylstyrene, butylstyrene, pentylstyrene, hexylstyrene. , dimethylstyrene, methylethylstyrene, methyl-10pylstyrene, diethylstyrene, ethylpropylstyrene, dipropylstyrene, trimethylstyrene, dimethylethylstyrene, methyldiethylstyrene, triethylstyrene, tripropylstyrene, etc. Vinyl having an aromatic hydrocarbon group Monomer; (meth)acrylonitrile, 2-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, aminemethylstyrene, dimethylaminomethylstyrene, methoxystyrene, methoxymethylstyrene,
Methyl (meth)acrylate, Ethyl (meth)acrylate, Propyl (meth)acrylate, Butyl (meth)acrylate, Pentyl (meth)acrylate, Hexyl (meth)acrylate, Octyl (meth)acrylate, ( Decyl (meth)acrylate, dotecyl (meth)acrylate, droxyethyl (meth)acrylate, aminoethyl (meth)acrylate, -N,N-dimethylaminoethyl (meth)acrylate, N-methyl (meth)acrylamide ,NN
-Vinyl monomers with substituents having a nitrogen atom or an oxygen atom, such as dimethyl (meth)acrylamide, vinyl acetate, vinyl benzoate, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, etc.; One type or two or more types can be used.

Moreover, the polymer <I) may have structural units other than the structural unit (A) and/or the structural unit (B). Examples of compounds that provide other structural units include ethylene, propylene, butylene, butadiene, isoprene, chloroprene, vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride, vinyl bromide, styrene fluoride, styrene chloride, and bromide. styrene, maleic acid,
Examples include maleic anhydride and fumaric acid, and one or more of these can be used.

When polymerization #(I) has other structural units, the proportion of the other structural units in the polymer (I) is preferably in the range of 30% by weight or less in the polymer (1). ) is larger than 30% by weight, the dispersion stability of the resulting electrorheological fluid may be poor. There are no particular restrictions on the method for obtaining hexapolymer (1). For example, (1) (meth)acrylic acid in the presence of a cationic catalyst at a temperature of (2) After adding an anionic polymerization initiator such as n-butyllithium to a vinyl monomer having an aromatic hydrocarbon group such as styrene, which is a compound providing the structural unit (B), and stirring for a predetermined time, A method of synthesis by adding a terminator having a vinyl group such as methacrylic acid chloride, (3) a method of synthesis by adding a terminator having a vinyl group such as methacrylic acid chloride, and (3) a method of synthesis by adding a terminator having a vinyl group such as methacrylic acid chloride. (Meth) acrylate, N, N-
A radical polymerization initiator such as azobisisobutyronitrile is added to a vinyl monomer having an aromatic hydrocarbon group such as dimethyl (meth) or acrylamide or a substituent having a nitrogen or oxygen atom, and the mixture is stirred for a predetermined period of time. Known methods can be used, such as a method in which a vinyl monomer that reacts with a chain transfer agent residue such as lysidyl (meth)acrylate is added and stirred to the polymerized product. Also, commercially available products may be used.

The vinyl monomer that can be polymerized in the presence of polymer (I) to produce polymer (II) which is effective as a polymer additive in the present invention is not particularly limited, and examples thereof include styrene, vinylnaphthalene, and vinyl monomer. Anthracene, vinylphenanthrene, vinyltoluene, ethylstyrene, propylstyrene, butylstyrene, pentylstyrene,
Hexylstyrene, dimethylstyrene, methylethylstyrene, methylpropylstyrene, diethylstyrene,
Vinyl monomers having aromatic hydrocarbon groups such as ethylpropylstyrene, dipropylstyrene, trimethylstyrene, dimethylethylstyrene, methyldiethylstyrene, triethylstyrene, tripropylstyrene: (meth)acrylonitrile, 2-vinylpyridine, 4 -vinylpyridine, N-vinylpyrrolidone, aminomethylstyrene, dimethylaminomethylstyrene, methoxystyrene,
Methoxymethylstyrene, methyl (meth)acrylate,
Ethyl (meth)acrylate, Propyl (meth)acrylate, Butyl (meth)acrylate, Pentyl (meth)acrylate, Hexyl (meth)acrylate, Octyl (meth)acrylate, Decyl (meth)acrylate, ( dodecyl (meth)acrylate, droxyethyl (meth)acrylate, aminoethyl (meth)acrylate, -N,N-dimethylaminoethyl (meth)acrylate, N-methyl (meth)acrylamide, N,N-dimethyl ( Vinyl monomers with a substituent having a nitrogen or oxygen atom such as meth)acrylamide, vinyl acetate, vinyl benzoate, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, etc.: ethylene, propylene, butylene, butadiene, isoprene, chloroprene, fluorine, etc. vinyl chloride,
Examples include other vinyl monomers such as vinylidene fluoride, vinyl chloride, vinylidene chloride, vinyl bromide, styrene fluoride, styrene chloride, styrene bromide, maleic acid, maleic anhydride, and fumaric acid. One or more of them can be used.

The average molecular weight of the polymer (I) having a vinyl group at one end is preferably in the range of 300 to 100,000. If the average molecular weight is less than 300 or greater than 100,000, the dispersion stability of the electrorheological fluid may be poor.

The ratio of the polymer (1) having a vinyl group at one end and the vinyl monomer is polymer (I)/vinyl monomer=0.
．． The range of 1/99.9 to 9515 (weight ratio) is preferable. When the polymer (I)/vinyl monomer ratio is smaller than 0.1/99.9 or larger than 9515, the amount added when the resulting polymer (II) is used as a polymer additive for electrorheological fluids. The dispersion stabilizing effect commensurate with that may not be obtained.

Polymer (II) is obtained by polymerizing vinyl monomers in the presence of polymer (I). There are no particular restrictions on the polymerization method; for example, a mixture of (1) polymer <1) and a vinyl monomer is dissolved in a solvent such as toluene, and a polymerization initiator such as azobisisobutyronitrile is added thereto. (2) Bulk polymerization by adding a polymerization initiator to a mixture of polymer (1) and vinyl monomer and heating at a predetermined temperature; ) and vinyl monomer, and if necessary, in the presence of a dispersion stabilizer or emulsifier, stir in a dispersion medium such as water or alcohol to suspend or emulsify and heat. It may be carried out by a known method such as suspension polymerization or emulsion polymerization.

The average molecular weight of the polymer (I[) is preferably in the range of 5,000 to 5,000,000. If the average molecular weight is less than 5,000 or greater than 5,000,000, the resulting electrorheological fluid may have poor dispersion stability.

The organic polymer particles having cation exchange ability constituting the dispersed phase in the electrorheological fluid of the present invention include polymer particles having a functional group that dissociates cations and becomes anions themselves in the presence of a polar solvent such as water. There are no particular limitations as long as the particles are agglomerated particles, and examples include particles of m-polymer having a dissociative group such as a sulfonic acid group, a carboxylic acid group, or a phosphoric acid group in the molecule. Among these, organic polymer particles having sulfonic acid groups are preferable, and particles made of polystyrene polymers containing sulfonic acid groups are particularly preferable because they provide an electrorheological fluid with excellent shear stress and current density.

There are no particular restrictions on the types of cations that organic polymer particles dissociate in polar solvents, such as hydrogen cations; lithium ions, sodium ions, potassium ions, calcium ions, aluminum ions, cuprous ions, and sulfur ions. Examples include metal cations such as copper ions; organic cations such as tetramethylammonium ions and pyridinium ions.

In order to obtain organic polymer particles having cation exchange ability that can be used as a dispersed phase in the present invention, for example, a vinyl compound having an ion dissociative group such as a sulfonic acid group or a carboxylic acid group may be used alone or in other forms as necessary. A monomer mixture containing a vinyl monomer may be polymerized by a known method and pulverized to a predetermined particle size if necessary, or an ionic dissociative group such as a sulfonic acid group may be introduced into the polymer by a known method. Alternatively, an ion dissociative group may be introduced by hydrolyzing a polymer having an ester group or the like by a known method.

Furthermore, a commercially available polystyrene-based ion exchange resin (for example, Amberlite ■Nato manufactured by Tokyo Organic Chemical Industry ■) pulverized to an appropriate particle size may be used.

In the present invention, the average particle diameter of the organic polymer particles constituting the dispersed phase is preferably in the range of 0.1 to 50 μm. If the average particle diameter of the organic polymer particles is less than 0.1 μm, a large shear stress may not be obtained when an electric field is applied to the prepared electrorheological fluid. Furthermore, if the average particle diameter of the organic polymer particles exceeds 50 μm, it may not be possible to obtain an electrorheological fluid with excellent dispersion stability when no electric field is applied.

The hydrocarbon compound constituting the main component of the dispersion medium in the electrorheological fluid of the present invention is not particularly limited as long as it is an insulating liquid consisting essentially of hydrocarbons, and examples include aliphatic compounds such as dodecane, hexatecane, and octadecane. Hydrocarbons; Aromatic hydrocarbons such as benzene, naphthalene, anthracene, and phenanthrene; Alkyl-substituted aromatic hydrocarbons such as toluene, ethylbenzene, and xylene; Therm-S ■30
0. Can you name hydrocarbon heating mediums such as THERM-S 700, THERM-S 800, THERM-S 900 (manufactured by Nippon Steel Chemical), and Nisseki Hysol 5AS-296 (made by Nippon Petrochemical)? One or more of these can be used. Additionally, other insulating liquids such as dialkyl ethers, alkylaryl ethers, diaryl ethers, alkyl halides, and aryl halides may be added and mixed to these hydrocarbon compounds to serve as a dispersion medium. It can also be used.

The electrorheological fluid of the present invention is obtained by mixing and dispersing the specific dispersed phase described above in a dispersion medium in the presence of a polymeric additive consisting of polymer (II).

The ratio of the dispersed phase to the dispersion medium in the electrorheological fluid of the present invention is preferably in the range of 50 to 500 parts by weight to 100 parts by weight of the former. If the amount of the dispersion medium exceeds 500 parts by weight, the shear stress obtained when an electric field is applied to the prepared electrorheological fluid may not be sufficiently large. Furthermore, if the amount of the dispersion medium is less than 50 parts by weight, the fluidity of the prepared electrorheological fluid itself may be reduced, making it difficult to use it as an electrorheological fluid.

Further, the amount of the polymer additive made of polymer (II) in the electrorheological fluid of the present invention is preferably in the range of 0.1 to 60 parts by weight based on 100 parts by weight of the dispersed phase. If the amount of the polymer additive is less than 0.1:1, an electrorheological fluid with excellent dispersion stability in the absence of an applied electric field may not be obtained.

Furthermore, if the amount of the polymer additive exceeds 60 parts by weight, not only will the dispersion stability not improve as much as the amount added, but other performances as an electrorheological fluid may be impaired. Undesirable.

The electrorheological fluid of the present invention may contain, for example, a surfactant, a polymer (II
) Other conventionally known additives such as polymeric dispersants and polymeric thickeners can be added as necessary.

<Effects of the Invention> The electrorheological fluid of the present invention has excellent current characteristics in that it generates a large shear stress even when a relatively weak electric field is applied, and the current density flowing at that time is small, and the electrorheological fluid can generate a large shear stress even when a relatively weak electric field is applied. Clutches, It can be effectively used for dampers, brakes, shock absorbers, actuator valves, etc.

(Example) The present invention will be explained below with reference to Examples, but the scope of the present invention is not limited to these Examples.6 Reference Example 1 A stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube 150 g of xylene, methoxypolyethylene glycol methacrylate (NK Ester M230G manufactured by Shin-Nakamura Chemical Co., Ltd.) was placed in a 500 m1 four-bottle flask, and the weight average molecular weight was measured using a Super System Controller PC data processing device (Tosoh I!). 1,400
) and 149 g of dodecyl methacrylate were charged, 0.7 g of azobisisobutyronitrile was added thereto, and the mixture was stirred at room temperature for 30 minutes while introducing nitrogen. Thereafter, polymerization was carried out by heating at 70°C for 10 hours and then further heating at 90°C for 2 hours.

The solid content of the resulting xylene solution of the polymer (hereinafter referred to as polymer solution (1)) was 5.
It was 0% by weight. When the polymerization rate was measured from the residual rate of the monomer, the polymerization rate of dodecyl methacrylate was 100%.
It was 520,000.

Reference Example 2 150 g of xylene was placed in a 500 ml four-eye flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube.
Polystyrene with a methacrylic group at one end (As-6 manufactured by Toagosei Kagaku Kogyo ■, whose weight average molecular weight was measured in the same manner as Reference Example 1 and found to be 16°000) 135zr
and 15 g of N,N'-dimethylacrylamide were charged, and 0.5 g of azobisisobutyronitrile was added thereto, followed by stirring at room temperature for 30 minutes while introducing nitrogen. then 7
Polymerization was carried out by heating at 0°C for 10 hours and then further heating at 90°C for 2 hours.

The solid content of the resulting xylene solution of the polymer (hereinafter referred to as polymer solution (2)) was 5.
It was 0% by weight. When the polymerization rate was measured in the same manner as in Reference Example 1, the polymerization rate of N,N'-dimethylacrylamide was 100%.

The weight average molecular weight of the polymer was measured in the same manner as in Reference Example 1 and was found to be 29,000.

Reference Example 3 150 g of xylene was placed in a 500 ml four-bottle flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube, and polybutyl acrylate having a methacrylic group at one end (AB-6 manufactured by Toagosei Chemical Co., Ltd.) ;Weight average molecular weight as Reference Example 1
Measured in the same manner as 13. OOO) 120
g, 15 g of dodecyl methacrylate and 15 g of 4-vinylpyridine were charged, and 0.9 g of azobisisobutyronitrile was added thereto, followed by stirring at room temperature for 30 minutes while introducing nitrogen. After heating at 75℃ for 10 hours,
Polymerization was carried out by heating at °C for 2 hours.

The solid content of the resulting xylene solution of the polymer (hereinafter referred to as polymer solution (3)) was 5.
It was 0% by weight. When the polymerization rate was measured using the same machine as in Reference Example 1, the polymerization rate of dodecyl methacrylate was 100%.
-The polymerization rate of vinylpyridine was 99%.The weight average molecular weight of the 0 polymer was measured in the same manner as in Reference Example 1.
8. .

It was 00.

Reference Example 4 In a 500 ml four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 150 g of xylene was added, and a copolymer of styrene and acrylonitrile having a methacrylic group at one end (manufactured by Toagosei Chemical Industry Co., Ltd.) AN-6, the weight average molecular weight was measured in the same manner as Reference Example 1 and was 13,000.
) and 140 g of styrene were charged, 055 g of azobisisobutyronitrile was added thereto, and the mixture was stirred at room temperature for 30 minutes while introducing nitrogen. Thereafter, the mixture was heated at 65°C for 20 hours and then further heated at 90°C for 2 hours to perform polymerization.

Step 4: The solid content of the obtained xylene solution of the polymer (hereinafter referred to as polymer solution (4)) was measured.
It was 931% by weight. When the polymerization rate was measured in the same manner as in Reference Example 1, the polymerization rate of styrene was 98%. When the weight average molecular weight of the polymer was measured in the same manner as in Reference Example 1,
It was 190,000.

Reference Example 5 In a 500 ml fourth flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 150 g of xylene, methoxypolyethylene glycol methacrylate (NK Ester M-90G manufactured by Shin Nakamura Chemical Industry ■, weight average molecular weight was measured in the same manner as Reference Example 1 and found to be 500)1
g and 149 g of hexadecyl methacrylate,
0.8 g of azobisisobutyronitrile was added thereto, and the mixture was stirred at room temperature for 30 minutes while introducing nitrogen. Then 70℃
After heating at 90° C. for 10 hours, polymerization was carried out by further heating at 90° C. for 2 hours.

Step 5: The solid content of the obtained xylene solution of the polymer (hereinafter referred to as polymer solution (5)) was measured.
It was 0% by weight. When the polymerization rate was measured in the same manner as in Reference Example 1, the polymerization rate of hexadecyl methacrylate was 100%.
Met. The weight average molecular weight of the polymer was measured in the same manner as in Reference Example 1 and was found to be 320,000.

Reference Example 6 200 g of isopropyl alcohol and 50 g of N-vinylpyrrolidone were charged into a 300 ml fourth flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, and 2.2'-azobis(2 -(2-imidacillin-2-yl)propane) (VA-06 manufactured by Wako Tsumugi
1) 2 g was added and stirred at room temperature for 30 minutes while introducing nitrogen. Thereafter, the mixture was heated at 70°C for 8 hours and then further heated at 90°C for 4 hours to perform polymerization. This solution was added dropwise to diisopropyl ether and stirred, and the precipitate was filtered and taken out. The precipitate was dried by heating at 50° C. for 24 hours in a vacuum dryer to obtain a powder.

This powder (30K) was placed in a 300ml four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, and the mixture was filled with 40g of dioxane and 1 liter of isopropyl alcohol.
0g, add lysidyl methacrylate 10E and heat at 60°C.
Do not heat or stir for hours.

The obtained reaction solution was added dropwise to diisopropyl ether and stirred, and the precipitate was filtered and taken out. The precipitate was heated in a vacuum dryer at 50°C for 24 hours, dried, and a vinyl group was added to one end. A polymer having the following was obtained.

The weight average molecular weight of the obtained polymer having a vinyl group at one end was measured in the same manner as in Reference Example 1, and found to be 21.000.
Met.

Next, 15 mL of xylene was added to a 500 ml four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube.
0+r, 9g of the above polymer having a vinyl group at one end and 141" of styrene were charged, 1.2g of azobisisobutyronitrile was added thereto, and the mixture was stirred at room temperature for 30 minutes while introducing nitrogen.Then, the mixture was stirred at 70°C. After heating at 90° C. for 10 hours, polymerization was carried out by further heating at 90° C. for 2 hours.

Step 4: The solid content of the obtained xylene solution of the polymer (hereinafter referred to as polymer solution (6)) was measured.
It was 8% by weight. # When the polymerization rate was measured in the same manner as Example 1, the polymerization rate of styrene was 97%. When the weight average molecular weight of the polymer was measured using the same machine as Reference Example 1, it was found to be 1.
It was 90,000.

Reference Example 7 150 g of xylene and 150 g of dodecyl methacrylate were placed in a 500 ml four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, and 0.7 g of azobisisobutyronitrile was added thereto, and nitrogen was introduced into the flask. The mixture was stirred at room temperature for 30 minutes while introducing . Thereafter, the mixture was heated at 70°C for 10 hours and then further heated at 90°C for 2 hours to perform polymerization.

The solid content of the resulting xylene solution of the polymer (hereinafter referred to as polymer solution (7)) was 5.
It was 0% by weight. When the polymerization rate was measured from the residual rate of monomer, the polymerization rate of dodecyl methacrylate was 100%.
Met. In addition, the weight average molecular weight of the polymer was measured using a super system controller PC data processing device (Tosoh Corporation).
It was 470,000.

Example 1 Ion-exchanged water i2 was added to a 3 000 ml four-loaf flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube.
After adding and dissolving 16.0 g of Oog and Kuraray Bobal PVA-205 (manufactured by Kuraray, polyvinyl alcohol), 250 g of styrene, industrial divinylbenzene (manufactured by Wako Tsumugi Kogyo, 55% by weight of divinylbenzene, ethylstyrene) A mixture consisting of 50 g of 35% by weight mixture) and 5 g of benzoyl peroxide was added. Thereafter, the contents of the flask were dispersed using a disperser (rotation speed: 2000 rpm) and heated at 70° C. for 8 hours.

The obtained solid substance was filtered, thoroughly washed with acetone and water, and then dried at 80°C for 12 hours using a hot air drier to obtain a polymerized crosslinked product (hereinafter referred to as polymerized crosslinked product (1)). 29
1g was obtained.

Next, 100 g of this polymerized crosslinked product (1) was placed in a 1,000 ml three-bottle flask equipped with a stirrer, a reflux condenser, and a thermometer, and 98% by weight of sulfur D 500 was added under water cooling.
g was added dropwise, and the mixture was heated at 80° C. for 24 hours with stirring to carry out a sulfonation reaction. Thereafter, the contents of the flask were poured into 0°C water, filtered and washed with water.

The obtained solid was dissolved in a 10% by weight aqueous sodium hydroxide solution 3
After neutralizing with 80 ml, the solution was thoroughly washed with water.

Thereafter, it was dried at 80° C. for 10 hours using a vacuum dryer to obtain 184 g of organic polymer particles (hereinafter referred to as dispersed phase particles (1)) having an average particle diameter of 2.5 μm. In addition,
The anionic dissociative group density of the dispersed phase particles (1) was 4.2 equivalents/g.

After drying 30 g of dispersed phase particles (1) at 150°C for 3 hours, the polymer solution obtained in Reference Example 1 (1) was left in a room at a temperature of 20°C and a relative humidity of 60% for 40 minutes to absorb moisture. ”z
The electrorheological fluid (1) of the present invention was obtained by adding r to 65 g of Therm-S ■900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical ■) and dispersing it in a dispersion medium.

Example 2 Reference Example 2 was used instead of the polymer solution (1) in Example 1.
Using 3 g of the polymer solution (2) obtained in
Electrorheological fluid (2) of the present invention was obtained in the same manner as in Example 1, except that the amount of 900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.) was 67 g.

Example 3 Reference Example 3 was used instead of the polymer solution (1) in Example 1.
Using 2 g of the polymer solution (3) obtained in
Electrorheological fluid (3) of the present invention was obtained in the same manner as in Example 1, except that the amount of 900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Co., Ltd.) was changed to 68 g.

Example 4 500 equipped with reflux condenser, thermometer and nitrogen inlet tube
72 g of sodium styrene sulfonate, 8 g of N,N'-methylenebisacrylamide, 1 g of sodium persulfate, and 320 g of ion-exchanged water were placed in a three-ml adjustable flask, and polymerization was carried out by heating at 70'C for 8 hours. . After drying the obtained polymer at 150°C for 3 hours, it was crushed and
The mixture was classified to obtain 46 g of organic polymer particles (hereinafter referred to as dispersed phase particles (2)) having an average particle diameter of 3.5 μm.

The anionic dissociative group density of the dispersed phase particles (2) is 4.
0 ■equivalent/"was.

After drying 30 g of the obtained dispersed phase particles (2) at 150'C for 3 hours, the polymer obtained in Reference Example 4 was left in a room at a temperature of 20°C and a relative humidity of 60% for 45 minutes to absorb moisture. The electrorheological fluid (4) of the present invention was obtained by adding 5 g of the solution (4) to 65 g of Therm-S ■900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Company) and dispersing it in a dispersion medium.

Example 5 Reference Example 5 was used instead of the polymer solution (4) in Example 4.
Example 1 except that the polymer solution (5) Log obtained in Example 1 was used, and a mixture of 50 t of dodecylbenzene and 10 g of diphenyl ether was used instead of THERM-S 900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical). Electrorheological fluid (5) of the present invention was obtained by the same method as in Example 4.

Example 6 Reference Example 6 was used instead of the polymer solution (4) in Example 4.
Example 4 except that the polymerization temperature Kg and (6) 3 ir obtained in Example 4 was used, and the amount of Therm-S ■900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical ■) was 67 g.
The electrorheological fluid (6) of the present invention was obtained in the same manner as in Example 1. Comparative Example 1 30 g of dispersed phase particles (1) in Example 1 were heated at 50°C.
After drying for 3 hours in a room with a temperature of 20℃ and a relative humidity of 60% for 40 minutes to absorb moisture, 70g of Therm-S ■
900 (partially hydrogenated triphenyl manufactured by Nippon Steel Chemical Company) to obtain a comparative electrorheological fluid (hereinafter referred to as comparative flow #(1)).

Comparative Example 2 Reference Example 7 was used instead of the polymer solution (1) in Example 1.
A comparative electrorheological fluid (hereinafter referred to as comparative fluid (2)) was obtained in the same manner as in Example 1, except that 5 g of the polymer solution (7) obtained in Example 1 was used.

Comparative Example 3 Reference Example 2 was used instead of the polymer solution (2) in Example 2.
A comparative electrorheological fluid (hereinafter referred to as "AS-6" manufactured by Toagosei Chemical Industry Co., Ltd.) was used in the same manner as in Example 2, except that 3 g of polystyrene having a methacrylic group at one end (AS-6 manufactured by Toagosei Chemical Industry Co., Ltd.) was used. , this was called comparative fluid (3)).

Comparative Example 4 After drying 30 g of the dispersed phase particles (1) in Example 1 at 150°C for 3 hours, it was left in a room at a temperature of 20°C and a relative humidity of 60% for 40 minutes to absorb moisture, and then 5 g of ricinoleic acid was dried at 60%.
The mixture was mixed and dispersed in a dispersion medium obtained by adding it to 5 g of Therm-S ■900 to obtain a comparative electrorheological fluid (hereinafter referred to as comparative fluid (4)).

Comparative Example 5 30 g of particles with an average particle diameter of 2.5 μm obtained by crushing and classifying commercially available silica gel (manufactured by Kanto Kagaku ■) were heated at 150'C for 30 minutes.
After drying for an hour, leave it in a room with a temperature of 20°C and a relative humidity of 60% for 1 hour to absorb moisture, and then apply 7at Therm-S ■900.
to obtain an electrorheological fluid for comparison (hereinafter referred to as comparison fluid (5)).

Example 7 Electrorheological fluids (1) to (6) and comparative fluids (1) to (5) of the present invention obtained in Examples 1 to 6 and Comparative Examples 1 to 5
), measure the viscosity at 23°C with no electric field applied. Then each electrorheological fluid is heated to a height of 15011
IfI, diameter 151] from the bottom of the test tube 1001111
It was filled up to 1 and sealed.

Thereafter, it was allowed to stand for 10 days, and the degree of sedimentation of the dispersed phase particles was observed to examine the dispersion stability of the electrorheological fluid.

The results are shown in Table 1.

In addition, each of the electrorheological fluids was put into a double cylindrical rotational viscometer with a coaxial electric field, and the inner/outer cylinder gap 1. Omrn, shear rate 400 s-', nesting temperature 25°C, AC external electric field 400
The shear road force value (initial value) when 0 V/drudge (frequency: 50 Hz) was applied and the current density (initial value) flowing at that time were measured.

Furthermore, the shear road force value (value after 3 days) and current density (value after 3 days) after continuous operation of the viscometer at 25°C for 3 days with an external electric field of 4000 V/m+n applied.
We measured the stability of electrorheological fluids over time. The results are shown in Table 1.

(Note 1) Dispersion stability
) to (6) have excellent current characteristics in that they generate large shear path force even when a relatively weak electric field is applied, and the current density flowing at that time is small, and they have excellent current characteristics such that the shear path force and current density are low even when a relatively weak electric field is applied. It had excellent stability over time, and not only had a low viscosity when no electric field was applied, but also had particularly excellent dispersion stability.

On the other hand, comparative fluids (1), (2), (3), and (4) obtained large shear path forces by applying a relatively weak electric field, but had poor current characteristics and dispersion when no electric field was applied. It was also less stable. Comparative fluid (4) was also inferior in stability over time when an electric field was applied. Comparative fluid (5) could not obtain a large shear path force by applying a relatively weak electric field, and its stability over time and dispersion stability when no electric field was applied were also poor.

Claims (1)

[Scope of Claims] 1. An electric device containing a dispersed phase made of organic polymer particles having cation exchange ability, a dispersion medium made of an insulating liquid mainly composed of a hydrocarbon compound, and a polymer additive. A viscous fluid characterized by using a polymer (II) obtained by polymerizing a vinyl monomer in the presence of a polymer (I) having a vinyl group at one end as a polymer additive. electrorheological fluid. 2. The average molecular weight of the polymer (II) serving as the polymer additive is 5.
2. The electrorheological fluid of claim 1, wherein the electrorheological fluid has a molecular weight in the range of 0.000 to 5.0 million. 3. A polymer (I) having a vinyl group at one end has a general formula ▲ mathematical formula, chemical formula, table, etc. as the main component of the main chain ▼ (However, in the formula, R^1 and R^2 each independently (Hydrogen or methyl group.) Structural unit (A) and/or general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the formula, R^3 is hydrogen or methyl group, and X is A polymer having a structural unit (B) represented by (an aromatic hydrocarbon group or a substituent having a nitrogen atom or an oxygen atom) and having an average molecular weight in the range of 300 to 100,000. The electrorheological fluid according to any one of 1 to 2. 4. The ratio of the polymer (I) having a vinyl group at one end and the vinyl monomer is polymer (I)/vinyl monomer = 0.1/99.9 to 95/5 (weight ratio). The electrorheological fluid according to any one of claims 1 to 3, wherein the electrorheological fluid is within the range of 5. The electrorheological fluid according to any one of claims 1 to 4, wherein the organic polymer having cation exchange ability is an organic polymer having a sulfonic acid group. 6. The electrorheological fluid according to any one of claims 1 to 5, wherein the organic polymer having cation exchange ability is a sulfonic acid group-containing polystyrene polymer. 7. The proportions of the dispersed phase, dispersion medium and polymer additive are
The electrorheological fluid according to any one of claims 1 to 6, wherein the dispersion medium is in the range of 50 to 500 parts by weight and the polymer additive is in the range of 0.1 to 60 parts by weight based on 100 parts by weight of the dispersed phase. 8. The electrorheological fluid according to any one of claims 1 to 7, wherein the organic polymer particles having cation exchange ability have an average particle diameter in the range of 0.1 to 50 μm.