JPH07173487A - Electroviscous fluid - Google Patents

Abstract

PURPOSE:To obtain a fluid which comes to have a high shearing stress and has good dispersion stability by dispersing dielectric particles and a particulate or substantially insoluble specific additive into an electrical-insulating oil to impart a specific structural viscosity to the resulting fluid. CONSTITUTION:This fluid comprises dielectric particles as a dispersed phase and an electrical-insulating oil as a dispersion medium. It has a viscosity of 0.5Pa.s or lower as measured at 25 deg.C at a shear rate of 33sec<-1> without an electric field, and has a structural viscosity satisfying equation I (wherein eta1 and eta2 are the viscosities as measured at 25 deg.C at shear rates of 3.3sec<-1> and 33sec<-1>, respectively, without an electric field). An embodiment thereof contains dielectric particles having an average particle diameter of 1-50mum as the dispersed phase in an amount of 100 pts.wt. per 50-500 pts.wt. the dispersion medium. For the purpose of imparting dispersion stability and re-dispersibility, an additive is used which is either in the form of particles satisfying equation II (wherein XB and XA are the average particle diameters of the additive and the dispersed-phase particles, respectively) or insoluble in the insulating oil. The additive preferably has structural units containing a silicone and structural units containing a segment capable of being adsorbed onto the dispersed phase.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrorheological fluid. More specifically, a large shear stress is generated even by applying a relatively weak electric field, and the current density that the current density at that time is small is excellent in current characteristics, and the generated shear stress and current density are excellent in stability over time, and Dispersion stability under the condition that no electric field is applied (ability to hold electrorheological fluid uniformly for a long time without causing the dispersed phase to settle or float), redispersibility (dispersed phase to settle or float and become non-uniform) The present invention relates to an electrorheological fluid that is particularly excellent in the ability to reproduce an original uniform state with a simple external force) and the fluidity (the ability to have a low viscosity when no electric field is applied).

[0002]

2. Description of the Related Art As an electrorheological fluid which generates a high shear stress, for example, a powdery substance of an ion exchange resin suspended in a higher alkyl ester of an aromatic carboxylic acid (Japanese Patent Laid-Open No. 50-92278), 3 Conductive particles covered with a crystalline substance that conducts an electric current along only one of the two crystal axes, a dielectric liquid and a steric stabilizer (JP-A-1-170693) and an electrically insulating thin film. Has been proposed as a dispersed phase (Japanese Patent Laid-Open No. 64-6093). However, these electrorheological fluids have poor dispersion stability when no electric field is applied, poor redispersibility after sedimentation or floating, and poor fluidity when the concentration of the dispersed phase is increased. Had a point.

Using modified polysiloxane as an additive to improve dispersion stability (Japanese Patent Publication No. 3-39560).
No. 4), a polymer using a polymer containing an ester group structure and an aromatic group structure (JP-A-4-96997), and the like. However, these additives have a problem that the redispersibility after sedimentation is lowered although the sedimentation rate of the dispersed phase can be suppressed.

An electrorheological fluid using fine particles as an additive for improving redispersibility (Japanese Patent Laid-Open No. 3-160).
094 and JP-A-3-166295) have been proposed. However, in these electrorheological fluids, the shear stress value obtained when an electric field is applied is reduced by the addition of fine particles, and because the dispersion stability is poor, the usage conditions of the electrorheological fluid are limited, and the device However, there is a problem that a re-dispersion mechanism is required.

Further, in order to improve dispersion stability, redispersibility and fluidity, a polymerizable monomer (A) such as a (meth) acryloyl group-containing polyethylene glycol is used as an additive and a polyfunctional polymerizable monomer. A monomer comprising at least one polymerizable monomer (B) selected from a monomer and a silicon-containing polymerizable monomer as an essential component and, if necessary, other polymerizable monomer (C). An electrorheological fluid (EP-052) using a copolymer (I) obtained by polymerizing a mixture.
9 166) have been proposed. However, these electrorheological fluids have a problem of poor fluidity because a large amount of additives must be used in order to improve dispersion stability.

[0006]

Therefore, the object of the present invention is to generate a large shear stress even by applying a relatively weak electric field, and when the current density flowing at that time is small, the current characteristics are excellent, Excellent shear stress and current density stability over time, and dispersion stability in the absence of an electric field (the ability to hold electrorheological fluid uniformly for a long time without letting the total dispersion settle or float). Dispersibility (the ability to reproduce the original uniform state with a simple external force after the dispersed phase has settled or floated to become non-uniform) and fluidity (the viscosity is low when no electric field is applied) It is to provide a particularly excellent electrorheological fluid.

[0007]

[Means for Solving the Problems] The above object is an electrorheological fluid composed of a dispersion medium composed of dielectric particles and an electric insulating oil, and shear measured at 25 ° C. without applying an electric field. The viscosity in a sheared state at a speed of 33 / s is 0.5 Pa · s or less, and the formula (1) 0.01 Pa · s ≦ η ₁ −η ₂ ≦ 0.5 Pa · s (1) (where, , Η ₁ is 25 ° C., the viscosity in a shear state at a shear rate of 33 / s measured without applying an electric field, η
₂ is the shear rate measured at 25 ° C without applying an electric field 3
It is a viscosity in a sheared state of 3 / s. ) Is achieved by an electrorheological fluid characterized by exhibiting a structural viscosity.

The present invention also includes the following embodiments.

(1) The average particle size of the dielectric particles is 1 to 50.
The electrorheological fluid which is μm.

(2) The electrorheological fluid, wherein the amount of the dispersion medium is 50 to 500 parts by weight per 100 parts by weight of the dispersed phase.

(3) The electrorheological fluid, wherein the electric insulating oil is a silicone type insulating oil or a fluorine type insulating oil.

(4) The electrorheological fluid comprising a dispersed phase composed of dielectric particles, a dispersion medium composed of electrically insulating oil, and an additive.

(5) When the additive is particulate in the electrically insulating oil and the average particle size XB of the additive is the average particle size XA of the dispersed phase particles, the formula (2) 3/10 <XB / The electrorheological fluid satisfying the condition of XA <3 (2).

(6) The electricity as described above, wherein the additive is substantially insoluble in the electric insulating oil and has both the structural unit (A) containing a silicone component and the structural unit (B) containing a dispersed phase adsorbing chain. Viscous fluid.

(7) The electrorheological fluid, wherein the additive is blended in an amount of 0.01 to 6 parts by weight per 100 parts by weight of the dispersed phase.

(8) The additive is a composite (I) obtained by composite of particles (I) substantially insoluble in electrically insulating oil and a polysiloxane-containing polymer (II), wherein the polymer ( I
I) is a structural unit (A) containing a silicone component and represented by the general formula (3)

[0017]

[Chemical 11]

(In the formula, A represents -COO- or a phenylene group, R ¹ represents a hydrogen atom or a methyl group,
R ² is an alkylene group having 1 to 6 carbon atoms, R ^{3 to} R ¹³ are the same or different and each represents an aryl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, and a is arbitrary. , B is an integer of 0 to 200, and c and d are the same or different and are an integer of 0 to 10, respectively. ) The polysiloxane-containing structural unit (A-
1) and the general formula (4) as the structural unit (B) containing a dispersed phase adsorptive chain.

[0019]

[Chemical 12]

(In the formula, B represents -COOR or a phenylene group, R ¹⁴ represents a hydrogen atom or a methyl group,
R ¹⁵ is an alkylene group having 2 to 4 carbon atoms, R ¹⁶ is a hydrogen atom or an alkyl group, e is an arbitrary integer, and f is 2 to 10
Indicates an integer of 0. ) An alkylene oxide chain-containing structural unit (B-1) represented by the general formula (5)

[0021]

[Chemical 13]

A nitrogen-containing atom chain-containing structural unit (B-2) represented by and / or general formula (6)

[0023]

[Chemical 14]

(In the formula, E represents —COO— or a phenylene group, R ¹⁹ represents a hydrogen atom or a methyl group,
R ²⁰ represents an alkyl group having 1 to 30 carbon atoms, and i represents an arbitrary integer. ) A long-chain hydrocarbon chain-containing structural unit (B
-3) The electrorheological fluid, which has at least one kind of dispersed phase adsorptive chain-containing structural unit (B) selected from the group consisting of 3).

(9) The ratio of the polysiloxane-containing polymer (II) to the particles (I) substantially insoluble in the electrically insulating oil in the composite (1) is 0.1 parts by weight with respect to 100 parts by weight of the former. To 100 parts by weight of said electrorheological fluid.

(10) The electrorheological fluid, wherein the composite (1) is a composite of the polysiloxane-containing polymer (II) on the surface of particles (I) which are substantially insoluble in the electrically insulating oil.

(11) The composite (1) comprises particles (I) substantially insoluble in an electrically insulating oil and a polysiloxane-containing polymer (I).
The electrorheological fluid, which is a composite of I) with a chemical bond.

(12) Polysiloxane-containing polymer (I
I) is the general formula (7)

[0029]

[Chemical 15]

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

[0031]

[Chemical 16]

(In the formula, G represents -COO- or phenylene group, R ³⁴ represents hydrogen atom or methyl group, and R ³⁴ represents
³⁵ represents an alkylene group having 2 to 4 carbon atoms, R ³⁶ represents a hydrogen atom or an alkyl group, and m represents an integer of 2 to 100. ) An alkylene oxide chain-containing monomer (bm-
1), general formula (9)

[0033]

[Chemical 17]

A monomer containing a nitrogen-containing atom chain represented by (b-
2) and / or general formula (10)

[0035]

[Chemical 18]

(In the formula, K represents --COO-- or a phenylene group, R ³⁹ represents a hydrogen atom or a methyl group, and R ³⁹ represents
⁴⁰ represents an alkyl group having 1 to 30 carbon atoms. ) At least one disperse phase adsorptive chain-containing monomer (b) selected from the hydrocarbon chain-containing monomers (b-3) represented by The electrorheological fluid obtained by polymerizing a monomer mixture (X) containing (c).

(13) The ratio of the silicon-based macromer (am) to the dispersed phase adsorptive chain-containing monomer (b) in the monomer mixture (X) is such that
90% by weight, dispersed phase adsorptive chain-containing monomer (b) 10-9
The electrorheological fluid in the range of 0% by weight.

(14) The composite (1) is obtained by dispersion-polymerizing the polymerizable monomer (α) in the presence of the polysiloxane-containing polymer (II) to obtain particles (I) substantially insoluble in the electric insulating oil. ) The electrorheological fluid obtained by producing

(15) The composite (1) is substantially insoluble in electrical insulation by emulsion polymerization of the polymerizable monomer (α) in an aqueous medium in the presence of the polysiloxane-containing polymer (II). The electrorheological fluid obtained by producing particles (I).

(16) The composite (1) uses organic or inorganic fine particles introduced with a polymerizable reactive group as the particles (I) substantially insoluble in the electric insulating oil, and the presence of the organic or inorganic fine particles. The electrorheological fluid obtained below by polymerizing a monomer mixture (X) to produce a polysiloxane-containing polymer (II).

(17) The additive is a polymer (1) which is substantially insoluble in an electrically insulating oil and has a polysiloxane-containing polymer (III), wherein the polymer (III) contains a silicon component. As the structural unit (A) of the general formula (3)
The polysiloxane-containing structural unit (A-1) and the dispersed-phase adsorptive chain-containing structural unit (B) represented by the general formula (11)

[0042]

[Chemical 19]

(In the formula, L represents -COO- or a phenylene group, R ⁴¹ represents a hydrogen atom or a methyl group,
R ⁴² represents an alkyl group having 8 to 30 carbon atoms, and S represents an arbitrary integer. ) The structural unit (B-4) containing a long-chain alkyl chain represented by the formula (B) is included in the electrorheological fluid.

(18) The additive polymer (1) is a composite (2) of particles (I) substantially insoluble in an electric insulating oil and a polysiloxane-containing polymer (III), (I
II) is a polysiloxane-containing structural unit (A) represented by the general formula (3) as the silicone component-containing structural unit (A).
-1) and the long-chain alkyl chain-containing structural unit (B-4) represented by the general formula (11) as the dispersed phase adsorptive chain-containing structural unit (B).

(19) 0.1 to 100 parts by weight of the polysiloxane-containing polymer (III) is blended per 100 parts by weight of the particles (I) substantially insoluble in the electrically insulating oil in the composite (2). The electrorheological fluid.

(20) The electrorheological fluid, wherein the composite (2) is a composite of the polysiloxane-containing polymer (III) on the surface of particles (I) substantially insoluble in the electrically insulating oil.

(21) The electrorheological fluid in which the particles (I) substantially insoluble in the electrically insulating oil and the polysiloxane-containing polymer (III) are combined through a chemical bond.

(22) Polysiloxane-containing polymer (II
I) is a silicone-based macromer (am) represented by the general formula (7) and a general formula (12).

[0049]

[Chemical 20]

(Wherein M represents a --COO-- or phenylene group, R ⁴³ represents a hydrogen atom or a methyl group, and R ⁴⁴ represents an alkyl group having 8 to 30 carbon atoms). Monomer mixture (Y) containing body (b-4) as an essential component and optionally other monomer (d)
The electrorheological fluid obtained by polymerizing.

(23) The proportion of the silicone macromer (am) and the long-chain alkyl group-containing monomer (b-4) in the monomer mixture (Y) is in the range of 10 to 90% by weight, respectively. The electrorheological fluid.

(24) Composite (2) In the presence of the polysiloxane-containing polymer (III), the polymerizable monomer (A) is dispersed and polymerized to form particles (I) substantially insoluble in the electrical insulating oil. The electrorheological fluid obtained by generating the electrorheological fluid.

(25) The composite (2) is an organic or inorganic fine particle having a polymerizable reactive group introduced as the particle (I) substantially insoluble in the electric insulating oil, and in the presence of the organic or inorganic fine particle, The electrorheological fluid obtained by polymerizing a monomer mixture (Y) to produce a polysiloxane polymer (III).

[0054]

The required performances for realizing a device using an electrorheological fluid include dispersion stability, redispersibility and fluidity. In other words, the development of a fluid with excellent dispersion stability, redispersibility, and fluidity while maintaining the stress characteristics that the shear stress value generated when an electric field is applied is large and the current characteristics that the current density flowing at that time is small Was desired. The inventors of the present invention believe that these required performances depend on the existence state of the dispersed phase in the dispersion medium, and maintain the viscosity of the electrorheological fluid in a state in which no electric field is applied while maintaining a low value. It was found that the addition of structural viscosity improves the dispersion stability, redispersibility and fluidity of the electrorheological fluid. That is, the electrorheological fluid of the present invention is required to exhibit the above-mentioned specific viscosity and structural viscosity represented by a specific conditional expression.

The structural viscosity exhibited by the electrorheological fluid in the present invention means the expression of viscosity by the structure composed of the dispersion phase and the dispersion medium formed by the weak aggregation of the dispersion phases in the dispersion medium. This structural viscosity is controlled by the magnitude of the interaction acting between the dispersed phases, and imparts suitable dispersion stability and redispersibility to the electrorheological fluid.

Further, since the electrorheological fluid exhibiting the structural viscosity is preferably used in the device, the electrorheological fluid of the present invention is
Shear rate 33 / s measured at 5 ° C without applying an electric field
It is necessary that the viscosity in the sheared state is 0.5 Pa · s or less, preferably 0.2 Pa · s or less,
Particularly preferably, it is 0.01 to 0.1 Pa · s. 0.
When the viscosity is more than 5 Pa · s, there are problems that the fluidity becomes poor and the electrorheological effect when an electric field is applied cannot be sufficiently obtained, or a device design problem occurs.

The structural viscosity of the electrorheological fluid of the present invention must satisfy the condition of the following formula (I).

0.01 Pa · s ≦ η ₁ −η ₂ ≦ 0.5 Pa · s (I) (wherein η ₁ is a shear state at a shear rate of 3.3 / s measured at 25 ° C. without applying an electric field. Viscosity, η ₂ is shear rate 33/25 measured at 25 ° C without applying an electric field.
s is the viscosity in the sheared state (hereinafter, η ₁ −η ₂ is T
i-value). ) That is, as shown in the equation (1), the electrorheological fluid of the present invention has a Ti value of 0.01 Pa · s.
It is preferable that it is not less than 0.5 Pa · s and not more than 0.5 Pa · s. More preferably, the Ti value is 0.05 Pa · s or more and 0.1 Pa · s or less. Within this range, the electro-rheological fluid satisfies the dispersion stability, redispersibility and fluidity at a higher level. can do. Ti
If the value is less than 0.01 Pa · s, the structural viscosity may be insufficient and the dispersion stability may be insufficient. Also,
When the Ti value exceeds 0.5 Pa · s, the fluidity in the state where no electric field is applied may be insufficient.

The average particle size of the dielectric particles to be the dispersed phase particles of the electrorheological fluid of the present invention is preferably in the range of 1 to 50 μm, particularly preferably 3 to 20 μm. When the average particle size of the dispersed phase is less than 1 μm,
It is difficult to obtain a large shear stress when an electric field is applied to the prepared electrorheological fluid. Further, when the average particle size of the dielectric particles exceeds 50 μm, it becomes difficult to obtain an electrorheological fluid having excellent dispersion stability in the state where no electric field is applied.

The dielectric particles to be the dispersed phase particles of the electrorheological fluid of the present invention are not particularly limited as long as they are particles that polarize in the state where an electric field is applied, and examples thereof include starch, cellulose, ion exchange resins and sulfonic acid groups. Containing polystyrene-based polymer particles or other hydrophilic group-containing organic particles; silica,
Hydrophilic inorganic particles such as alumina and zeolite; particles having a three-layer structure in which a conductive thin film layer is formed around the surface of organic solid particles, and an electrically insulating thin film layer is further formed, and conductive particles such as aluminum. Particles having a thin film insulating layer formed on the surface thereof, composite particles having conductive particles such as carbon black dispersed in a resin; particles using carbonaceous powder; organic semiconductors such as poly (acene-quinone) Particles: Examples include ferroelectric particles such as barium titanate and lithium tartrate. Among the above-mentioned dielectric particles, a large shear stress value obtained when an electric field is applied,
It is preferable to use sulfonic acid group-containing polystyrene-based polymer particles because the current density flowing at that time is small and the stability over time is excellent.

As the dispersion medium of the electrorheological fluid of the present invention,
There is no particular limitation as long as it is an electrically insulating oil. For example, silicone oil such as polydimethylsiloxane, partially octyl-substituted polydimethylsiloxane, and partially phenyl-substituted polydimethylsiloxane; liquid paraffin, decane, methylnaphthalene, decalin, diphenylmethane, partially hydrogenated Hydrocarbons such as triphenyl; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, bromobenzene, chlorobiphenyl, chlorodiphenylmethane; low-polymerization products of ethylene trifluoride chloride such as Daifloyl (manufactured by Daikin Industries, Ltd.), demnum ( Perfluoropolyether oil such as Daikin Industries, Ltd., fluorine-modified silicone oil (fluorine oil such as Shin-Etsu Chemical Co., Ltd .; dioctyl phthalate, trioctyl trimellitate, dibutyl sebacate). And one or more of them can be used from the above. Considering the viscosity of the prepared electrorheological fluid in the state where no electric field is applied, the viscosity of the dispersion medium is 0.05p
It is preferably a · s or less.

The dispersion medium used in the electrorheological fluid of the present invention is preferably silicone type insulating oil or fluorine type insulating oil.

The silicone-based insulating oil is mainly composed of silicone oil, and is a substantially electrically insulating fluid.
There is no particular limitation. Silicone oil, which is the main component of silicone-based insulating oil, has a siloxane structure, and is generally used for braking oil, air insulating oil, impregnating injection oil, lubricating oil, polish, cosmetic ingredients, release agents, defoaming agents, etc. It is what As the silicone oil, for example, those mentioned above can be mentioned.

The fluorinated insulating oil is not particularly limited as long as it is a fluid containing fluorinated oil as a main component and being substantially electrically insulating. Fluorine-based oil, which is the main component of fluorine-based insulating oil, is a liquid having a fluorine atom, and is, for example, a low polymer of trifluoroethylene that is generally used as a lubricant, a mold release agent, etc. Examples thereof include perfluoropolyether oil used and fluorine-modified silicone oil used as a lubricant and the like.

The ratio of the dispersed phase to the dispersion medium in the electrorheological fluid of the present invention is 50 to 5 for the former 100 parts by weight.
It is preferably in the range of 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 may not be sufficiently large. Further, when the amount of the dispersion medium is less than 50 parts by weight, it may be difficult to use as a prepared electrorheological fluid.

In the present invention, the method of imparting the structural viscosity represented by the specific conditional expression to the electrorheological liquid while maintaining the specific viscosity described above is not particularly limited, but the use of an additive or the dispersed phase It is effective to treat the particle surface with a polymer compound.

Above all, it is preferable to use an additive added to a dispersion phase composed of dielectric particles and a dispersion medium composed of electric insulating oil.
It is preferable in consideration of reproducibility of dispersion stability and redispersibility of the obtained electrorheological liquid and easiness of production.

In particular, by using suitable additives,
Excellent dispersion stability can be easily imparted while maintaining the shear stress induced when an electric field is applied.

Dispersion stability in the present invention is evaluated by dispersing a dispersed phase in an electrically insulating oil at 30% by weight, adding an additive thereto to prepare an electrorheological fluid, and then applying a test tube (height: 150 m).
m, diameter 15 mm), and the mixture is sealed and left at room temperature to trace the sedimentation state of the dispersed phase. The height from the bottom of the test tube of the precipitate layer formed by the precipitation of the dispersed phase was allowed to stand and measured one week later, and the ratio of the supernatant layer produced was 40% or less, preferably 20%, based on the total amount of the electrorheological fluid.
When it is at most%, it can be evaluated that the dispersion stability is imparted.

The electrorheological fluid to which the dispersion stability is imparted in this way can be effectively used for various devices while maintaining a stable dispersion state even in a gentle stirring state or a stationary state.

In the present invention, (i) the additive is in the form of particles in an electrically insulating oil, and the additive has an average particle diameter X.
When B is the average particle size XA of the dispersed phase particles, the condition of formula (2) 3/10 <XB / XA <3 (2) is satisfied, and (ii) it is substantially insoluble in electrically insulating oil and Those having both the structural unit (A) containing a silicone component and the structural unit (B) containing a dispersed phase adsorptive chain can be preferably used.

When an additive such as (i) having a specific average particle size is used, an electrorheological fluid is obtained while imparting a structural viscosity represented by a specific conditional expression while maintaining a specific viscosity. It is possible to obtain a well-balanced electrorheological liquid without deteriorating the shear stress characteristics required for.

The average particle size XA of the disperse phase and the average particle size XB of the additive in the present invention are the averages in the state in which the disperse phase and the additive are dispersed in the electrically insulating oil used when preparing the electrorheological fluid. It is the particle size. For example, the average particle diameter XB of the additive can be measured by dispersing the additive in silicone oil and using a particle size distribution meter (Shimadzu laser diffraction particle size distribution analyzer SALD-1000 manufactured by Shimadzu Corporation). it can.

In the formula (1), XB / XA is 3/10
In the following cases, a suitable structural viscosity is given to the electrorheological fluid, but a problem may occur in that the shear stress required for the electrorheological fluid cannot be obtained.

In the formula (1), when XB / XA is larger than 3, there is a problem that the electrorheological fluid is not provided with a suitable structural viscosity.

The additive used in (i) is not particularly limited as long as it maintains a particulate shape in an electrically insulating oil, and examples thereof include polystyrene, poly (methacrylate, polyacrylonitrile, phenol resin, benzoguanamine resin, Examples thereof include organic particles such as melanin resin; inorganic particles such as silica and alumina; and composite particles in which a polymer is present on the surface of these organic particles or inorganic particles.

When a substance such as (ii) is used as the additive, the additive has a property of adsorbing to the particle surface of the dispersed phase, so that an interaction occurs between the additive and the particle surface of the dispersed phase. It Moreover, since the additive has a property of being compatible with the dispersion medium, an interaction also occurs between the additive and the dispersion medium. As a result, a three-membered structure is formed through the additive, but since the additive is substantially insoluble in the dispersion medium, it is possible to prevent the particles in the dispersed phase from coming into contact with each other. By using such a substance as an additive, it is possible to impart a structural viscosity represented by a specific conditional expression while maintaining a specific viscosity, and to obtain good dispersion stability, redispersibility and fluidity of the electrorheological fluid at the same time. Can be granted.

It is preferable that the additive is substantially insoluble in the electric insulating oil, but 90% by weight of the following soluble component may be contained. Further, the composite polymer may absorb the electric insulating oil to partially swell or may swell as a whole unless it is dissolved in the electric insulating oil to form a uniform solution. When the composite polymer is dissolved in the electric insulating oil or contains a large amount of soluble components exceeding 90% by weight without being dissolved, there is a problem that the redispersibility of the obtained electrorheological fluid is lowered. It happens.

The additive preferably has a structural unit (A) containing a silicone component. When the composite polymer does not have the structural unit (A), there may occur a problem that dispersion stability and fluidity of the obtained electrorheological fluid are deteriorated. The silicone component is a polydimethylsiloxane group,
A polydimethylsiloxane group having a partial alkyl group substitution, a polydimethylsiloxane group having a partial aryl group substitution, and a polysiloxane group such as a tris (trialkylsiloxy) silylpropyl group.

The additive preferably has a structural unit (B) containing a dispersed phase adsorptive chain. When the additive does not have the structural unit (B), the dispersion stability of the obtained electrorheological fluid may be deteriorated. The form of adsorption may be chemisorption or physical adsorption. However, if the interaction between the additive and the particle surface of the dispersed phase is too strong, the redispersibility and fluidity of the obtained electrorheological fluid may be reduced. Therefore, the form of adsorption is preferably physical adsorption or electrostatic chemical adsorption. The dispersion layer adsorptive chain is, for example, a functional group or functional group containing a hydrocarbon group, a nitrogen atom, an oxygen atom, or the like and exhibiting Lewis basicity.

In the present invention, as an additive that can be suitably used in imparting the structural viscosity represented by a specific conditional expression while maintaining a specific viscosity, for example, (1) an additive that is substantially insoluble in an electric insulating oil is used. The polymer (II) obtained as a composite unit of the particles (I) and the polysiloxane-containing polymer (II) is used as the structural unit (A) containing the silicone component and represented by the general formula (3).

[0082]

[Chemical 21]

(In the formula, A represents —COO— or a phenylene group, R ¹ represents a hydrogen atom or a methyl group,
R ² is an alkylene group having 1 to 6 carbon atoms, R ^{3 to} R ¹³ are the same or different and each represents an aryl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, and a is optional. , B and c are the same or different and each represents an integer of 0 to 10, and d represents an integer of 0 to 200. ) A polysiloxane-containing structural unit (A
-1), and the general formula (4) as the structural unit (B) containing a dispersed phase adsorptive chain.

[0084]

[Chemical formula 22]

(In the formula, B represents —COO— or a phenylene group, R ¹⁴ represents a hydrogen atom or a methyl group,
R ¹⁵ is an alkylene group having 2 to 4 carbon atoms, R ¹⁶ is a hydrogen atom or an alkyl group, e is an arbitrary integer, and f is 2 to 10
Indicates an integer of 0. ) An alkylene oxide chain-containing structural unit (B-1) represented by the general formula (5)

[0086]

[Chemical formula 23]

A nitrogen-containing atom chain-containing structural unit (B
-2) and / or general formula (6)

[0088]

[Chemical formula 24]

(In the formula, E represents -COO- or phenylene group, R ¹⁹ represents hydrogen atom or methyl group,
R ²⁰ represents an alkyl group having 1 to 30 carbon atoms, and i represents an arbitrary integer. ) A hydrocarbon chain-containing structural unit (B-
A composite (1) having at least one selected from the group consisting of (3) and (2) having a polysiloxane-containing polymer (III) substantially insoluble in an electrically insulating oil, Is a silicone unit-containing structural unit (A) represented by the general formula (3).
1) and the general formula (11) as the structural unit (B) containing a dispersed phase adsorptive chain.

[0090]

[Chemical 25]

(In the formula, L represents —COO— or a phenylene group, R ⁴² represents a hydrogen atom or a methyl group,
R ⁴² is an alkyl group having 8 to 30 carbon atoms, and S is an arbitrary integer), and an additive polymer (1) having a long hydrocarbon chain-containing structural unit (B-4) Can be mentioned. Among them, as the additive polymer (1), the composite (2) of the particles (I) substantially insoluble in the electric insulating oil and the polysiloxane-containing polymer (III) can be preferably used.

When an additive is used, the additive is the dispersed phase 10
It is preferable to add 0.01 to 6 parts by weight per 0 part by weight. When the amount of the additive is less than 0.01 part by weight, the obtained electrorheological fluid does not exhibit structural viscosity and dispersion stability may not be obtained. When the amount of the additive exceeds 6 parts by weight, the redispersibility and fluidity of the obtained electrorheological fluid may be significantly reduced. Further, it is particularly preferable that the amount is blended in the range of 0.1 to 5 parts by weight.

When the above-mentioned composite (1) is used as an additive, the composite (1) contains particles (I) substantially insoluble in the electrically insulating oil and the above-mentioned polysiloxane-containing structural unit (A).
-1) and a polysiloxane-containing polymer (II) having a structural unit (B) containing a dispersed phase adsorptive chain are complexed. However, the structural unit (B) includes the above-mentioned alkylene oxide chain-containing structural unit (B-1), nitrogen-containing atom chain-containing structural unit (B-2), and hydrocarbon chain-containing structural unit (B-3). At least one selected from the group can be selected, and through this complex (1),
It is possible to cause an appropriate interaction between the dispersed phase particles and the dispersion medium to give the electrorheological fluid dispersion stability, redispersibility and fluidity.

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

The particles (I) which are substantially insoluble in the electrically insulating oil to be complexed with the polysiloxane-containing polymer (II) are not particularly limited as long as they are substantially insoluble in the electrically insulating oil. For example, polystyrene, poly ( (Meth) acrylate, polyacrylonitrile, phenolic resin, benzoguanamine resin, melamine resin, etc. organic particles; silica, alumina, etc. inorganic particles; these organic or inorganic particles have hydroxyl groups, amino groups,
Organic or inorganic particles in which a condensation or addition reactive group such as a carboxyl group, epoxy group, or isocyanate group is introduced; organic or inorganic particles in which a polymerization reactive group such as a styryl group or (meth) acryloyl group is introduced Can be mentioned.

The composite (1) used in the present invention is a polysiloxane-containing polymer (II) containing the polysiloxane-containing structural unit (A-1) and the dispersed phase adsorptive chain-containing structural unit (B) as essential components. ) Has a part. The polysiloxane-containing structural unit (A-1) in the composite (1) causes an appropriate interaction between the composite (1) and the dispersion medium, and imparts dispersion stability and fluidity to the electrorheological fluid. can do. Polysiloxane-containing structural unit (A-1)
When it does not have, there may arise a problem that dispersion stability and fluidity of the electrorheological fluid are deteriorated. In addition, the structural unit (B) containing the disperse phase adsorptive chain in the composite (1) causes an appropriate interaction between the composite (1) and the particles of the disperse phase, thereby stabilizing the dispersion in the electrorheological fluid. Can be given. When the structural unit (B) containing the dispersed phase adsorptive chain is not included, there may occur a problem that the dispersion stability of the electrorheological fluid decreases.

Polysiloxane-containing polymer (I) for particles (I) substantially insoluble in electrically insulating oil in complex (1)
The ratio of I) is 0.1 to 100 parts by weight of the former and 0.1 to the latter.
It is preferably in the range of 100 parts by weight, more preferably in the range of 1 to 10 parts by weight. When the latter ratio is less than 1 part by weight, dispersion stability may not be imparted to the electrorheological fluid. If the latter ratio exceeds 100 parts by weight, redispersibility and fluidity may not be imparted to the electrorheological fluid.

The composite (1) is composed of the particles (I) substantially insoluble in the electrically insulating oil and the polysiloxane-containing polymer (II), but the composite form is not particularly limited. However, the composite (1) is preferably a composite of the polymer (II) on the surface of the particles (I). When the polymer (II) is not composited on the surface of the particles (I), dispersion stability may not be imparted to the electrorheological fluid.

The composite (1) is composed of the particles (I) substantially insoluble in the electrically insulating oil and the polysiloxane-containing polymer (I).
It is preferred that I) is complexed with a chemical bond. By forming a composite through the particles (I) and the polymer (II), the composite (1) as an additive suitable for the present invention can be easily obtained. Particle (I) and polymer (I
When the complexation with I) is not carried out via a chemical bond, the complex may not be a suitable additive for the present invention.

There is no particular limitation on the method for obtaining the composite (I) by complexing the particles (I) substantially insoluble in the electrically insulating oil and the polysiloxane-containing polymer (II). (I) Polymer (I)
I), particles (I) are formed in the presence of the particles, and the particles (I) are synthesized and complexed simultaneously. (Ii) The polymer (II) is formed in the presence of the particles (I) A method of simultaneously synthesizing and compounding (II), a method of synthesizing each of (iii) particles (I) and polymer (II), mixing and kneading, and then compounding by heat treatment or radiation treatment are adopted. can do.

When the composite method (i) is employed, the composite (1) is obtained by polymerizing the monomer mixture (X-1) (i-1) to obtain a polysiloxane-containing polymer (II). Then, in the presence of the obtained polymer (II), the polymerizable monomer (α) which gives particles (I) substantially insoluble in the electrical insulating oil by polymerization is dissolved to produce the polymer (particles (particles Dispersion polymerization in a solvent that does not dissolve (I)), (i-2) polymerizing the monomer mixture (X) to obtain the polysiloxane-containing polymer (I).
After obtaining I), the particles (I) substantially insoluble in the insulating liquid are obtained by polymerizing in the presence of the obtained polymer (II).
A method of emulsion-polymerizing a polymerizable monomer (α) which gives (i-3) a monomer mixture (X) to obtain a polysiloxane-containing polymer (II), In the presence of the obtained polymer (II), the polymerizable monomer (α) is solution polymerized in a solvent that also dissolves the polymerizable monomer (α) and the produced polymer (particles (I)). It is synthesized by using a method or the like. Among these, (i-1) and (i-2)
It is preferable to use the method (1) because the polymer (II) can be easily obtained with good reproducibility on the surface of the particles (I). Further, among the methods of (i-1), it is preferable to use a polymer (II) having an ethylenically unsaturated group introduced therein, in which the polymer (II) is particles (I).
It is particularly preferable because a complex complexed to the surface of (1) via a chemical bond can be easily obtained with good reproducibility.

When the compounding method (ii) is adopted, the compound (I) may be prepared by, for example, (ii-1) particles (I) substantially insoluble in silicone-based insulating oil, and the above-mentioned organic or inorganic particles. A method of polymerizing the monomer mixture (X) in the presence of the organic or inorganic fine particles to produce the polysiloxane-containing polymer (II), (ii-2) particles substantially insoluble in electrically insulating oil As (I), the monomer mixture (X) is polymerized in the presence of the above-mentioned organic or inorganic fine particles into which the condensation or addition-reactive group has been introduced to polymerize the polymer (I
Method I). (Ii-3) As the particles (I), the above-mentioned polymerization-reactive group-introduced organic or inorganic fine particles are used, the organic or inorganic fine particles are used, and in the presence of the organic or inorganic fine particles, the monomer mixture ( It is synthesized by using a method of polymerizing X) to form polymer (II). Among them, the methods (ii-2) and (ii-3) are used to obtain a composite (1) in which the polymer (II) is composited on the surface of the particle (I) through a chemical bond. Therefore, it is preferable. Furthermore (ii-
It is particularly preferable to use the method 3) because a complex in which the polymer (II) is complexed on the surface of the particle (I) via a chemical bond can be easily obtained with good reproducibility.

When the compounding method (iii) is adopted,
The composite (I) includes, for example, (iii-1) particles (I) substantially insoluble in an electrically insulating oil and a polysiloxane-containing polymer (I).
It is synthesized by using a method of mixing or kneading I) in the presence or absence of a solvent.

The process of synthesizing the complex (1) by the method (i-1) is shown below.

The polysiloxane-containing polymer (II) has the general formula (7):

[0106]

[Chemical formula 26]

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

[0108]

[Chemical 27]

(In the formula, G represents -COO- or a phenylene group, R ³⁴ represents a hydrogen atom or a methyl group,
R ³⁵ is an alkylene group having 2 to 4 carbon atoms, R ³⁶ is a hydrogen atom or an alkyl group, and m is an integer of 2 to 100. )
An alkylene oxide chain-containing macromer represented by (bm
-1), general formula (9)

[0110]

[Chemical 28]

A nitrogen-containing atom chain-containing monomer (b-
2) and general formula (10)

[0112]

[Chemical 29]

(In the formula, K represents —COO— or a phenylene group, R ³⁹ represents a hydrogen atom or a methyl group,
R ⁴⁰ represents an alkyl group having 1 to 30 carbon atoms. ) At least one disperse phase adsorptive chain-containing monomer (b) selected from the hydrocarbon chain-containing monomers (b-3) represented by It is obtained by polymerizing the monomer mixture (X) containing (c).

The proportion of the silicone macromer (am) in the monomer mixture (X) is preferably in the range of 10 to 90% by weight, particularly preferably 20 to 80% by weight. When the proportion of the silicone-based macromer (am) is less than 10% by weight or exceeds 90% by weight, dispersion stability and fluidity may not be imparted to the electrorheological fluid. The proportion of the dispersed phase adsorptive chain-containing monomer (b) in the monomer (X) is preferably in the range of 10 to 90% by weight, and preferably in the range of 20 to 80% by weight. Is particularly preferable. The ratio of the specific monomer (b) is 10% by weight
If the amount is less than 90% by weight or more than 90% by weight, the electrorheological fluid may not have sufficient dispersion stability.

When the method (i-1) is adopted, examples of the silicone macromer (am) used in the monomer mixture (X) include (meth) acryloyl group-containing polydimethylsiloxane and styryl group-containing polydimethylsiloxane. Polydimethylsiloxane, (meth) acryloyl group-containing partially octyl-substituted polydimethylsiloxane, styryl group-containing partially octyl-substituted polydimethylsiloxane, (meth) acryloyl group-containing partially phenyl-substituted polydimethylsiloxane, styryl group-containing partially phenyl Examples thereof include substituted polydimethylsiloxane and tris (trimethylsiloxy) silylpropyl (meth) acrylate. Among these, one kind or two or more kinds can be used.

Examples of the alkylene oxide chain-containing monomer (bm-1) used as the dispersed phase adsorptive chain monomer (b) include (meth) acryloyl group-containing polyethylene glycol, styryl group-containing polyethylene glycol,
p-isopropenylbenzyl group-containing polyethylene glycol, (meth) acryloyl group-containing polypropylene glycol, styryl group-containing polypropylene glycol, p
-Polyalkylene glycols having a double bond such as isopropenylbenzyl group-containing polypropylene glycol, (meth) acryloyl group-containing polytetramethylene glycol, styryl group-containing polytetramethylene glycol, and p-isopropenylbenzyl group-containing polytetramethylene glycol And the like, and one or more of them can be used.

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

Examples of the nitrogen-containing derivative of (meth) acrylic acid include those containing a substituted or unsubstituted amino group in the ester portion of the (meth) acrylic acid ester and the amide of (meth) acrylic acid. Aminoalkyl acrylate and (meth) acrylic acid amide are preferably used. Examples of aminoalkyl (meth) acrylate include dimethylaminoethyl N, N- (meth) acrylate, diethylaminoethyl N, N- (meth) acrylate, dimethylaminopropyl N, N- (meth) acrylate, Examples thereof include dimethylaminobutyl N, N- (meth) acrylate. Examples of (meth) acrylic acid amide include (meth) acrylamide and N- (meth)
Acrylamide, N-ethyl (meth) acrylamide,
N-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dimethylpropyl acrylamide, etc. are mentioned, and 1 or 2 or more types are selected from these. Can be used. Among these nitrogen-containing (meth) acrylic acid derivatives, those in which the nitrogen atom present is tertiaryized are particularly preferable.

As the unsaturated monomer having a nitrogen-containing heterocycle, a monocyclic or polycyclic heterocycle containing 1 to 3, preferably 1 or 2 ring nitrogen atoms is bonded to a vinyl group. A monomer is included, for example, 1-vinyl-2-pyrrolidone,
Vinylpyrrolidones such as 1-vinyl-3-pyrrolidone; Vinylpyridines such as 2-vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinylpyridine; 1
-Vinylimidazole, 1-vinyl-2-methylimidazole and the like (vinylimidazoles; N- (meth) acryloylmorpholine, N- (meth) acryloylpyridine and the like can be mentioned, and one or more of them can be used. Can be used.

Examples of the hydrocarbon chain-containing monomer (b-3) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) ) Octyl acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, 2-methylstearyl (meth) acrylate, (meth) Eicosyl acrylate, (meth)
(Meth) acrylic acid esters such as hexacosyl acrylate; long-chain alkyl group-substituted styrenes such as butyl styrene, octyl styrene, dodecyl styrene, and stearyl styrene can be mentioned, and one or more of them are used. be able to.

Examples of the other monomer (c) include olefins such as ethylene, propylene and cyclohexene; alkyl dienes such as butadiene, isoprene and cyclopentadiene; vinyl fluoride, vinylidene fluoride, vinyl chloride and chloride. Aromatic vinyl compounds such as vinylidene; aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, vinylnaphthalene, vinylanthracene, chlorostyrene and chloromethylstyrene; methoxybutyl acrylate (meth) acrylate (meth) ) (Meth) acrylic acid alkoxyalkyl esters such as methoxyethyl acrylate; hydroxyalkyl esters of (meth) acrylic acid such as 2-hydroxyethyl (meth) acrylate and hydroxybutyl (meth) acrylate; Esters of aromatic (meth) acrylate of an alcohol, such as data) Akurirue benzyl;
Addition product of glycidyl (meth) acrylate or hydroxyalkyl ester of (meth) acrylic acid with a monocarboxylic acid compound of acetic acid, propionic acid, lauric acid, linoleic acid, p-tert-benzoic acid having 2 to 18 carbon atoms "Viscoat 8F""Viscoat8FM" (Osaka Organic Chemical Co., Ltd., trade name, (meth) acrylates having a fluorine atom), fluorine atom-containing compounds such as perfluorocyclohexyl (meth) acrylate and perfluorocyclohexylethylene Vinyl esters such as vinyl acetate and vinyl benzoate; vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2-sulfoethyl (meth) acrylate, 3-sulfopropyl (meth )
Polymerizable unsaturated group-containing carboxylic acids such as acrylate and the like, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid and / or their sodium, calcium , An ammonium salt, a pyridinium salt, and other acidic dissociative group-containing monomers.

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

As the radical generating catalyst, any catalyst can be used as long as it is usually used for polymerization of vinyl monomers. Typical examples are azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile); benzoyl peroxide, di-tert-butyl peroxide. , Te
Examples thereof include peroxide compounds such as rt-butyl peroctoate and tert-butyl peroxy-2-ethylhexanoate, which are usually 0.2 to 10 parts by weight, preferably 100 parts by weight of the monomer. Is used in the range of 0.5 to 5 parts by weight.

The polymerization reaction temperature is usually about 60 to 100 ° C. and the reaction time is about 1 to 15 hours.

As the solvent, hexane, heptane,
Aliphatic hydrocarbons such as octane; benzene, toluene,
Aromatic hydrocarbons such as xylene; alcohols such as isopropyl alcohol and butanol; ketones such as methyl isobutyl ketone and methyl ethyl ketone; esters such as ethyl acetate, isobutyl acetate, amyl acetate and 2-ethylhexyl acetate; methyl cellosolve, Cellosolves such as ethyl cellosolve can be used.

After the completion of the polymerization, the obtained solution of the polymer (II) can be used as it is for the dispersion polymerization when the composite (1) is synthesized, or the solvent is distilled off to obtain the polymer (I).
I) can be taken out and used.

The polymer (II) is preferably reacted with a monomer having an ethylenically insoluble group to introduce an ethylenically unsaturated group into the polymer (II).

Polymers containing an ethylenically unsaturated group (I
By using I), when the composite (1) is synthesized, the polymerization product of the polymerizable monomer (α) and the polymer (I
Since it is chemically combined with I), the dispersion stability of the electrorheological fluid during storage and the dispersion stability after use under a high shear rate can be improved.

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

By the method (i-1), the composite (1) is obtained by dispersion-polymerizing the polymerizable monomer (α) in the presence of the polymer (II).

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

The organic solvent used in the dispersion polymerization of the method (i-1) does not substantially dissolve the composite (1) produced by the polymerization, but the polymer (II) and the polymerizable monomer are used. It is a good solvent for (α).

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

In the method (i-1), the polymer (II) is used.
The polymerizable monomer (α) to be polymerized in the presence of is not particularly limited as long as it is soluble in the above-mentioned organic solvent, and examples thereof include styrene, vinyltoluene, p-chlorotoluene, and vinylpyridine. Group compounds; (meta)
Examples thereof include (meth) acrylic acid esters such as methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and benzyl (meth) acrylate.

The dispersion polymerization for synthesizing the composite (1) in the method (i-1) is usually carried out using a radical generating catalyst. As the radical generating catalyst, for example, 2,2
Azo compounds such as ′ -azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylpareronitrile); peroxide compounds such as benzoyl peroxide and lauryl peroxide. These are usually used in an amount of 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer (α).

In the method (i-1), 0.1 to 10 parts by weight of the polymer (II) is added to 100 parts by weight of the polymerizable monomer (α) in the dispersion polymerization for synthesizing the composite (1). It is preferable to use within the range of, and more preferably within the range of 1 to 6 parts by weight. When the amount of the polymer (II) used is less than 0.1 part by weight, the dispersion polymerization for synthesizing the composite cannot be performed stably, or even when it is obtained, the dispersion stability of the prepared electrorheological fluid is improved. It may not be possible to improve it. If the amount of the polymer (II) used exceeds 10 parts by weight, the redispersibility or fluidity of the prepared electrorheological fluid tends to be poor.

Further, the total concentration of the polymerizable monomer (α) and the polymer (II) in the organic solvent is 5 to 50% by weight,
It is preferably 10 to 30% by weight. Further, in the dispersion polymerization, conventionally known dispersion stabilizers such as surfactants and polymer compounds may be appropriately mixed and used in an organic solvent.

The dispersion polymerization for synthesizing the composite in the method (i-1) may be carried out by a known polymerization method, usually at a temperature in the range of 60 to 100 ° C. for 0.5 to 30 hours. Done.

After completion of the polymerization, if necessary, a known method such as solvent substitution, solvent distillation, drying or pulverization can be used. In particular, it is preferable to use the silicone-based insulating oil as the solvent for the polymerization, since the workability in preparing the electrorheological fluid is improved.

The process of synthesizing the complex by the method (i-2) is shown below.

The composite (1) used in the method (i-2) is obtained by emulsifying the polymerizable monomer (α) in the presence of the polymer (II) in a medium containing water as a main component. Obtained by polymerizing.

The polymerization reaction in an aqueous medium when the composite is synthesized by the method (i-2) is preferably carried out using a water-soluble radical generating catalyst. The radical generating catalyst can be used without particular limitation as long as it is used in the emulsion polymerization of ordinary vinyl monomers, for example, sodium persulfate, potassium persulfate, ammonium persulfate, 4,4 ′. -Azobis-4-cyanovaleric acid, 2,2'-azobis-aminodipropane hydrochloride and the like can be mentioned.

In the method (i-2), 0.1 to 10 parts by weight of the polymer (II) is added to 100 parts by weight of the polymerizable monomer (α) in the polymerization reaction for synthesizing the composite (1). It is also preferable to use within the range of, and more preferably within the range of 1 to 6 parts by weight. When the amount of the polymer (II) used is less than 0.1 part by weight, the polymerization reaction for synthesizing the composite cannot be performed stably, and even when the composite is obtained, the dispersion stability is sufficient for the electrorheological fluid. May not be granted. The amount of the polymer (II) used is 10
If it exceeds the weight part, there is a problem that the redispersibility and fluidity of the prepared electrorheological fluid become poor.

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

The emulsion polymerization carried out for synthesizing the composite (1) by the method (i-2) may be carried out in an aqueous medium containing water or a mixed solvent with an organic solvent containing water as a main component. it can. As the organic solvent that can be used in the present invention, an organic solvent having a strong affinity for water, for example, methanol,
Examples thereof include alcohols such as ethanol and isopropanol, cellsolves such as methyl cellosolve and ethyl cellosolve, glycols such as ethylene glycol and diethylene glycol. When the mixed solvent is used, it is preferably used so that the polymerizable monomer (α) is not dissolved.

The polymerization reaction for synthesizing the composite (1) in the method (i-2) is usually carried out in the temperature range of 50 to 100 ° C. for about 2 to 40 hours.

The operation of the polymerization reaction is usually carried out by adding water and the polymer (II) to the reaction group and stirring them to obtain a uniform dispersion state, and a part of the polymerizable monomer (α) or all of the polymerizable monomer (α) if necessary. And then heated to a predetermined temperature, a radical generating catalyst is added to start the reaction. Further, the rest of the polymerizable monomer (α) is added, and the polymerization is carried out at a predetermined temperature in an emulsified state. After completion of the polymerization, it may be treated by a known method such as solvent substitution, solvent distillation, drying and pulverization, if necessary.

The process of synthesizing the complex (1) by the method (ii-3) is shown below.

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

Compound (e) having such two kinds of groups
Examples include vinyl group-containing silane coupling agents such as γ- (meth) acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltrichlorosilane; glycidyl (meth) acrylate, allylglycidyl ether. Glycidyl group-containing unsaturated compounds and the like.

The amount of the compound (e) for introducing the polymerization-reactive group into the organic or inorganic fine particles is not particularly limited, but it is 10 to 100 parts by weight of the organic or inorganic fine particles.
It is preferably used within the range of 100 parts by weight.

When the composite (1) is obtained by the method (ii-3), the polymerization of the monomer mixture (X) is carried out by the particles (I) consisting of organic or inorganic fine particles introduced with a polymerization reactive group. Is preferably used in the presence of a polymerization initiator in an organic solvent.

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

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

The polymerization is carried out at a temperature of from 50 to 100 ° C., and usually from 0.
It takes 5 to 15 hours.

After completion of the polymerization, if necessary, it may be treated by a known method such as solvent substitution, solvent distillation, drying and pulverization.

The above-mentioned additive polymer (1) as an additive
In the case of using, the additive polymer (1) is substantially insoluble in the electrical insulating oil, and the above-mentioned polysiloxane-containing structural unit (A-1) and long-chain alkyl chain-containing structural unit (B-4). A polysiloxane-containing polymer having
I). Through the additive polymer (1), it is possible to cause an appropriate interaction between the dispersed phase particles and the dispersion medium to impart dispersion stability, redispersibility and fluidity to the electrorheological fluid. .

Further, as the additive polymer (1), the particles (I) substantially insoluble in the electrically insulating oil, the above-mentioned polysiloxane-containing structural unit (A-1) and the long-chain alkyl chain-containing structural unit ( It is preferably a composite (2) with a polysiloxane-containing polymer having B-4).

The composite (2) is insoluble in electrically insulating oil. By being substantially insoluble in the dispersion medium, good redispersibility and fluidity can be imparted to the electrorheological fluid. When the additive is substantially soluble in the electric insulating oil, there may occur a problem that the electrorheological fluid cannot be provided with redispersibility and fluidity.

The composite (2) is a polysiloxane-containing structural unit (A-1) and a long-chain alkyl group-containing structural unit (B-4).
A polysiloxane-containing polymer (I
II) has a part. The polysiloxane-containing unit (A-1) in the polymer (III) causes an appropriate interaction between the composite (2) and the dispersion medium, and imparts dispersion stability and fluidity to the electrorheological fluid. can do. When the polysiloxane-containing structural unit (A-1) is not contained,
There is a problem that the dispersion stability and fluidity of the electrorheological fluid are reduced. In addition, the long chain alkyl group-containing structural unit (B-4) in the polymer (III) causes an appropriate interaction between the composite (2) and the dispersed phase particles, resulting in dispersion stability in the electrorheological fluid. Can be given. When the long-chain alkyl group-containing structural unit (B-4) is not included, the dispersion stability of the electrorheological fluid is deteriorated.

The composite (2) is preferably a composite of the particles (I) substantially insoluble in the electrically insulating oil and the polysiloxane-containing polymer (III). The particles (I) that are substantially insoluble in the electrically insulating oil that is complexed with the polysiloxane-containing polymer (III) are not particularly limited as long as they are substantially insoluble in the electrically insulating oil. For example, description of the complex (1) The same organic or inorganic particles as mentioned above can be mentioned.

In the present invention, the ratio of the polysiloxane-containing polymer (III) to the particles (I) substantially insoluble in the electrically insulating oil in the composite (2) is 0. It is preferably in the range of 1 to 100 parts by weight, more preferably in the range of 1 to 10 parts by weight. If the latter ratio is less than 0.1 part by weight, dispersion stability may not be imparted to the electrorheological fluid. If the latter ratio exceeds 100 parts by weight, redispersibility and fluidity may not be imparted to the electrorheological fluid.

The composite (2) comprises particles (I) substantially insoluble in silicone type insulating oil and a polysiloxane-containing polymer (I).
II) is preferably complexed, but the form of conjugation is not particularly limited, however, the complex (2) is a complex of the polymer (III) on the surface of the particle (I). It is preferable. Polymer (III) is particles (I)
If it is not composited on the surface of, the electrorheological fluid may not be able to be provided with dispersion stability.

The composite (2) is composed of the particles (I) substantially insoluble in the electrically insulating oil and the polysiloxane-containing polymer (II).
It is preferred that I) is complexed with a chemical bond. By complexing the particles (I) and the polymer (III) via a chemical bond, a complex as an additive suitable for the present invention can be easily obtained. When the composite of the particles (I) and the polymer (III) is not carried out through a chemical bond, the composite may not be a suitable additive for the present invention.

There is no particular limitation on the method for complexing the particles (I) substantially insoluble in the electrically insulating oil and the polysiloxane-containing polymer (III), and (iv) the particles (I) in the presence of the polymer (III). ) Is generated to simultaneously synthesize and complex particles (I), (v) Polymer (III) is produced in the presence of particles (I) to synthesize and complex polymer (II). Simultaneous method, (vi) particle (I) and polymer (I)
A method of synthesizing each of II), mixing and kneading, and then compounding by heat treatment, radiation treatment, or the like can be adopted.

When the compounding method of (iv) is adopted, the compound (2) is, for example, (iv-1) the monomer mixture (Y).
To give particles (I) which are substantially insoluble in the electrical insulating oil by polymerizing in the presence of the obtained polymer (II) after obtaining the polysiloxane-containing polymer (III). A method of dispersion-polymerizing a monomer (α) in a solvent that dissolves a weight-weight monomer (α) and does not dissolve a produced polymer (particles (I)), (iv-2) monomer mixture After polymerizing (Y) to obtain the polysiloxane-containing polymer (III), the polymerizable monomer (α) is added in the presence of the obtained polymer (III).
Of the polymerizable monomer (α) in a solvent that dissolves the polymer and the resulting polymer (particles (I)). Among these (iv-
It is preferable to use the method 1) because a complex in which the polymer (II) is complexed on the surface of the particles (I) can be easily obtained with good reproducibility. Further, among the methods of (iv-1), it is preferable to use a polymer (III) having an ethylenically unsaturated group introduced therein, in which the polymer (III) is bonded to the surface of the particle (I) through a chemical bond. It is particularly preferable because a complexed complex can be easily obtained with good reproducibility.

When the composite method (v) is adopted, the composite (2) uses, for example, (v-1) the organic or inorganic fine particles described above as the substantially unnecessary particles (I) in the electrically insulating oil, In the presence of the organic or inorganic fine particles, the monomer mixture (Y) is polymerized to produce a polysiloxane-containing polymer (II
Method (I), (v-2) using the organic or inorganic fine particles introduced with the condensation or addition-reactive group described above as the particles (I) substantially insoluble in the electric insulating oil. A method of polymerizing the monomer mixture (Y) in the presence to produce the polymer (III), (v-
3) As the particles (I), organic or inorganic fine particles having the above-mentioned polymerizable reactive group introduced therein are used, and the monomer mixture (Y) is polymerized in the presence of the organic or inorganic fine particles to obtain the polymer (III). Is generated by using a method of generating Among them, the use of the methods (v-2) and (v-3) gives a complex in which the polymer (III) is complexed on the surface of the particle (I) through a chemical bond. ,preferable. Further, the use of the method (v-3) is particularly preferable because a complex in which the polymer (III) is complexed on the surface of the particle (I) via a chemical bond can be easily obtained with good reproducibility.

When the composite method (vi) is adopted, the composite (2) may be, for example, (vi-1) the particles (I) substantially insoluble in the electrically insulating oil, and the polysiloxane-containing polymer (II).
It is synthesized by using a method of mixing or kneading I) in the presence or absence of a solvent.

The process of synthesizing the complex by the method (iv-1) is shown below.

The polysiloxane-containing polymer (III) is
General formula (7)

[0171]

[Chemical 30]

(In the formula, F represents —COO— or a phenylene group, R ²¹ represents a hydrogen atom or a methyl group,
R ²² is an alkylene group having 1 to 6 carbon atoms, R ^{23 to} R ³³ are the same or different and each represent an aryl group, an alkyl group having 1 to 6 carbon atoms or a 1 to 10 no alkoxy group, and j and k are The same or different and the integer of 0-10 shows 1 and the integer of 0-200, respectively. ) A silicone-based macromer (am) represented by

[0173]

[Chemical 31]

(In the formula, M represents -COO- or a phenylene group, R ⁴³ represents a hydrogen atom or a methyl group,
R ⁴⁴ represents an alkyl group having 8 to 30 carbon atoms. ) A long chain alkyl group-containing monomer (b-4) as an essential component, and by polymerizing a monomer mixture (Y) containing another monomer (d) as necessary. can get.

The proportion of the silicone macromer (am) in the monomer mixture (Y) is preferably in the range of 10 to 90% by weight, particularly preferably 20 to 80% by weight. When the proportion of the silicone macromer (am) is less than 10% by weight or exceeds 90% by weight, dispersion stability and fluidity may not be imparted to the electrorheological fluid. Further, the proportion of the long chain alkyl group-containing monomer (b-4) in the monomer (Y) is preferably in the range of 10 to 90% by weight, and is preferably in the range of 20 to 80% by weight. Is particularly preferred. The ratio of long chain alkyl group-containing monomer is 10
If it is less than 90% by weight or more than 90% by weight, the dispersion stability of the electrorheological fluid may not be sufficient.

Examples of the silicone-based macromer (am) include those mentioned in the description of the composite (1).

Examples of the long chain alkyl group-containing monomer (b-4) include octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, cetyl (meth) acrylate. Long-chain alkyl esters of (meth) acrylic acid such as stearyl (meth) acrylate, 2-methylstearyl (meth) acrylate, eicosyl (meth) acrylate, and hexacosyl (meth) acrylate; octylstyrene, dodecylstyrene , Long-chain alkyl group-substituted styrenes such as stearyl styrene, and one or more of them can be used.

In the monomer mixture (Y), the silicone macromer (am) and the long chain alkyl group-containing monomer (b-
In addition to 4), other monomer (c) can be used if necessary, and can be used in the range of less than 80% by weight in the monomer mixture (Y). (However, the total amount of the monomers (a), (b) and (d) is 100% by weight.) Examples of such other monomer (d) include ethylene, propylene and cyclohexene. Olefins; Alkyl dienes such as butadiene, isoprene, cyclopentadiene; Halogenated olefins such as vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride; Styrene, t-butylstyrene, vinylnaphthalene, vinylanthracene, chlorostyrene , Aromatic vinyl compounds such as chloromethylstyrene; (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate;
(Meth) acrylic acid methoxybutyl, (meth) acrylic acid methoxyethyl and other (meth) acrylic acid alkoxyalkyl esters; (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid hydroxybutyl and other (meth) acrylic acid Hydroxyalkyl esters of acrylic acid;
Esters of directional alcohol such as benzyl (meth) acrylate with (meth) acrylic acid; glycidyl (meth) acrylate or hydroxyalkyl ester of (meth) acrylic acid and acetic acid, propionic acid, lauric acid, linoleic acid, C-C18 such as p-tert-benzoic acid
An adduct with a monocarboxylic acid compound;
F "" Viscoat 8FM "(Osaka Organic Chemical Co., Ltd.,
Trade names, fluorine atom-containing (meth) acrylates, fluorine atom-containing compounds such as perfluorocyclohexyl (meth) acrylate, perfluorocyclohexylethylene; vinyl esters such as vinyl acetate, vinyl benzoate; (meth) acrylonitrile N, N- (meth) acrylic acid dimethylaminoethyl, N, N- (meth) acrylic acid diethylaminoethyl, N, N- (meth) acrylic acid dimethylaminopropyl, N, N- (meth) acrylic acid dimethylamino Aminoalkyl (meth) acrylates such as butyl and salts thereof such as hydrochlorides, hydrobromides and sulfates; (meth) acrylamides, N-methyl (meth) acrylamides, N-ethyl (meth) acrylamides, N -Butyl (meth) acrylamide, N,
(Meth) acrylic acid amides such as N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dimethylpropylacrylamide; 1-
Vinylpyrrolidones such as vinyl-2-pyrrolidone and 1-vinyl-3-pyrrolidone; Vinylpyridines such as 2-vinylpyridine, 4-vinylpyridine and 5-methyl-2-vinylpyridine; 1-vinylimidazole, 1- Vinyl imidazoles such as vinyl-2-methylimidazole;
Examples thereof include nitrogen-containing heterocyclic compounds such as N- (meth) acryloylmorpholine and N- (meth) acryloylpyridine.

As a polymerization method for obtaining the polymer (III), a known polymerization method may be adopted, for example, a solution polymerization method using a radical generating catalyst.

As the radical generating catalyst, any catalyst can be used as long as it is usually used for polymerization of vinyl monomers. Typical examples include azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile); benzoyl peroxide, di-tert-butylperoxide. Oxide, ter
Examples thereof include peroxide compounds such as t-butyl peroctoate and tert-butyl peroxy-2-ethylhexanoate, which are usually 0.2 to 10 parts by weight, preferably 100 parts by weight of the monomer. Is used in the range of 0.5 to 5 parts by weight.

The polymerization reaction temperature is usually about 60 to 100 ° C. and the reaction time is about 1 to 15 hours.

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

After the completion of the polymerization, the obtained solution of the polymer (III) can be used as it is for the dispersion polymerization when synthesizing the composite (2) as an additive, or the solvent is distilled off. The polymer (III) can also be taken out and used.

The polymer (III) is preferably reacted with a monomer having an ethylenically unsaturated group to introduce the ethylenically unsaturated group into the polymer (III).

Polymers containing an ethylenically unsaturated group (I
By using II), since the polymerization product of the polymerizable monomer (α) and the polymer (III) are chemically bound during the synthesis of the composite, the dispersion of the electrorheological fluid during storage can be achieved. Stability and dispersion stability after use under high shear rates can be improved.

The introduction of the ethylenically unsaturated group into the polymer (III) is carried out, for example, when synthesizing the polymer (III), acrylic acid, methacrylic acid, maleic acid or vinyl sulfone is added to one component of the monomer mixture. This can be carried out by using an acid group-containing monomer such as an acid and reacting the acid group with a glycidyl group-containing unsaturated monomer such as glycidyl (meth) acrylate or allyl glycidyl ether.

In the method (iv-1), the polymer is obtained by dispersion-polymerizing the polymerizable monomer (α) in the presence of the polymer (III).

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

The organic solvent used in the dispersion polymerization does not substantially dissolve the polymer produced by the polymerization, but is a good solvent for the polymer (III) and the polymerizable monomer (α). It is a thing.

Examples of the organic solvent include aliphatic hydrocarbons such as hexane, heptane, octane; aromatic hydrocarbons such as benzene, toluene, xylene; methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol. And other alcohols; ether-based organic solvents such as cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, ethyl acetate and isobutyl, ketone-based, ester-based organic solvents, etc., and one or more of them may be used as a mixture. You can

In the method of (iv-1), the polymer (II
The polymerizable monomer (α) that is polymerized in the presence of I) is not particularly limited as long as it is soluble in the above organic solvent, and examples thereof include styrene, vinyltoluene, p-chlorotoluene, vinylpyridine and the like. Aromatic compounds; methyl (meth) acrylate, ethyl (meth) acrylate,
Examples thereof include (meth) acrylic acid esters such as propyl (meth) acrylate and benzyl (meth) acrylate.

In the method of (iv-1), the complex (2)
The dispersion polymerization for synthesizing is usually carried out using a radical generating catalyst. Examples of the radical generating catalyst include azo compounds such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile); and benzoyl peroxide and lauryl peroxide. Oxide compounds and the like are mentioned, and these are usually
It is used in an amount of 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer (α).
If it is less than 0.2 parts by weight, the polymerization may take a long time. If the amount exceeds 10 parts by weight, no further effect is usually obtained.

In the method of (iv-1), the complex (2)
In the dispersion polymerization for synthesizing the polymerizable monomer (α) 100
It is preferable to use the polymer (III) within a range of 0.1 to 10 parts by weight, and more preferably within a range of 1 to 6 parts by weight, based on parts by weight. When the amount of the polymer (III) used is less than 0.1 part by weight, the dispersion polymerization for synthesizing the composite cannot be performed stably, or even when it is obtained, the dispersion stability of the prepared electrorheological fluid is improved. It may not be possible to improve it. Further, when the amount of the polymer (III) used exceeds 10 parts by weight, the redispersibility and fluidity of the prepared electrorheological fluid tend to be poor.

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

The dispersion polymerization at the time of synthesizing the polymer (III) may be carried out by a known polymerization method, usually 60 to 100.
It is carried out at a temperature in the range of ° C for 0.5 to 30 hours.

After completion of the polymerization, if necessary, it may be treated by a known method such as solvent substitution, solvent distillation, drying and pulverization. In particular, it is preferable to use the silicone-based insulating oil after substituting the polymerization solvent because the workability in preparing an electrorheological fluid is improved.

The process of synthesizing the complex (2) by the method (v-3) is shown below.

When the method (v-3) is used, organic or inorganic fine particles having a polymerizable reactive group introduced therein are used as the particles (I) substantially insoluble in the dispersion medium. The particles having a polymerizable reactive group are prepared by treating the organic or inorganic fine particles with the compound (e) having a functional group capable of reacting with the functional group existing on the surface of the organic or inorganic fine particles and a polymerizable reactive group. It is obtained by things.

Compound (e) having such two kinds of groups
Examples include vinyl group-containing silane coupling agents such as γ- (meth) acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltrichlorosilane; glycidyl (meth) acrylate, allylglycidyl ether. Glycidyl group-containing unsaturated compounds and the like.

The amount of the compound (e) used for introducing the polymerizable reactive group into the organic or inorganic fine particles is not particularly limited, but is 10 to 100 parts by weight of the organic or inorganic fine particles.
It is preferably used within the range of 100 parts by weight. If it is less than 10 parts by weight, the introduction of the polymerizable reactive group to the fine particles may not be sufficient. Further, in the range of more than 100 parts by weight, it is usual that no further effect can be obtained.

When the composite (2) is obtained by the method (v-3), the polymerization of the monomer mixture (Y) is carried out by the particles (I) consisting of organic or inorganic fine particles having a polymerizable reactive group introduced therein. Is preferably used in the presence of a polymerization initiator in an organic solvent.

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

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

Polymerization is carried out at 50 to 100 ° C., preferably 60 to
At a temperature of 90 ° C., usually for 0.5 to 15 hours, preferably 4 to
It takes 10 hours.

After completion of the polymerization, if necessary, it may be treated by a known method such as solvent substitution, solvent distillation, drying and pulverization.

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

[0207]

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

Reference Example 1 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 150 g of toluene, 1 g of azobisisobutyronitrile, polydimethylsiloxane containing a methacryloyl group (manufactured by Chisso Corporation). 50 g of average molecular weight = about 5000) and 50 g of cetyl methacrylate were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 75 ° C. for 3 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (1).

350 g of isopropyl alcohol, 2 g of polymer (1), 2 g of azobisisobutyronitrile and 50 g of styrene were added to a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. Then, the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. 200 g of 0.02 Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, and then the volatile component was distilled off by drying under reduced pressure with an evaporator to give a styrene-based graft polymer. Additive (1) silicone oil dispersion (additive (1)
Content of 20% by weight, hereinafter referred to as additive dispersion (1))
Got

Reference Example 2 200 ml of methanol and 100 ml of deionized water were mixed in a 300 ml flask, and silica gel fine particles (manufactured by Nippon Shokubai Co., Ltd., spherical, average particle diameter 1.5 μm) were mixed therein.
m) 100 g was dispersed. 7 g of γ-methacryloxypropyltrimethoxysilane was added thereto and reacted at 70 ° C for 1 hour, the solvent was distilled off by heating, and the obtained reaction product was dried at 60 ° C under reduced pressure.

Toluene 300 m in 500 ml of thruster
100 g of the above reaction product obtained by drying and adding 1 was dispersed. There, 1 g of azobisisobutyronitrile, methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight = about 5)
000, silicon content = 36%) and 3 g of hexyl methacrylate were dissolved and reacted at 70 ° C. for 5 hours. After completion of the reaction, the solvent is distilled off by heating under reduced pressure,
Additive consisting of surface-treated silica gel particles (2)
Got

Reference Example 3 200 g of ion-exchanged water was placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
1 g of reactive emulsifier Aqualon RN-20 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkylstyryl ether), 1 g of dodecyl methacrylate and 1 g of sodium persulfate were added and dissolved. 50 g of methyl methacrylate and 5 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene and 35% by weight of ethylstyrene, manufactured by Wako Pure Chemical Industries, Ltd.) were added thereto as a monomer component, while blowing nitrogen. 20000 by disperser
Stir for 2 minutes on rotation. This was heated at 70 ° C. for 3 hours and further heated at 90 ° C. for 3 hours to carry out a polymerization reaction. After the polymerization was completed, the dispersion medium was azeotropically converted from water to isopropyl alcohol, and then mineral electric insulating oil (high-pressure insulating oil manufactured by Cosmo Oil Co., Ltd.) was added, and isopropyl alcohol was distilled off under reduced pressure to give methyl methacrylate. A mineral-based electrically insulating oil dispersion (additive (3) content 20% by weight, hereinafter referred to as additive dispersion (3)) of additive (3) consisting of a system crosslinked polymer microgel was obtained.

Reference Example 4 150 g of toluene, 1.5 g of azobisisobutyronitrile, 80 g of styrene and 20 g of dodecyl methacrylate were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. Then, the mixture was stirred for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 20 hours and stirred at 85 ° C. for 4 hours to carry out a polymerization reaction. After the reaction was completed, the volatile matter was distilled off under reduced pressure to obtain a comparative additive (1) composed of a styrene-dodecyl methacrylate copolymer.

Example 1 1.2 L of water was charged into a 3-liter 4-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, and Kuraray Poval PVA-205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) 16 After adding and dissolving 0.0 g, 270 g of styrene and divinylbenzene for industrial use (manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene 55
%, A mixture of 35% by weight of ethylstyrene, etc.) 30 g
And a mixture of 8 g of azobisisobutyronitrile was added. Then, the contents in the flask were dispersed at a stirring speed of 7,000 rpm, and polymerization was carried out at 80 ° C. for 8 hours. The obtained solid matter was separated by filtration, washed thoroughly with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain 289 g of a spherical crosslinked polymer (hereinafter referred to as crosslinked polymer (1)).

Next, 100 g of the crosslinked polymer (1) was charged into a 2-liter 4-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel, and 98 wt% concentrated sulfuric acid 700
g was added to form a uniform dispersion liquid. Increase the temperature of the reaction mixture to 8
After raising the temperature to 0 ° C., the mixture was heated and stirred at the same temperature for 24 hours to carry out a sulfonation reaction. Then, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water. The obtained solid was neutralized with 500 ml of a 10 wt% sodium hydroxide aqueous solution and then thoroughly washed with water. Then, use a vacuum dryer at 80 ° C for 1
After drying for 0 hours, 298 g of sulfonic acid group-containing polystyrene polymer particles having an average particle diameter of 6 μm (hereinafter referred to as dispersed phase particles (1)) were obtained. The anion dissociative group density of the dispersed phase particles (1) was 4.2 mg equivalent / g.

30 g of the dispersed phase particles (1) were dried at 150 ° C. for 3 hours, and then the moisture content in the atmosphere was absorbed to adjust the water content to 2.0% by weight, and then the additive obtained in Reference Example 1 was added. 1 g of the dispersion liquid (1) was added to 0.02 Pa · s of silicone oil (KF96-20cs, manufactured by Shin-Etsu Chemical Co., Ltd.) 6
It was uniformly dispersed in a dispersion medium obtained by adding 9 g to obtain an electrorheological fluid (1) of the present invention.

Example 2 In place of the additive dispersion liquid (1) in Example 1, 0.5 g of the additive (2) obtained in Reference Example 2 was used and 0.02P
0.02 Pa · s instead of a · s silicone oil
Silicone oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.
The electrorheological fluid (2) of the present invention was prepared in the same manner as in Example 1 except that a mixed solution of 19.5 g of 6-20 cs) and 50 g of a fluorinated oil (Daifloir # 1 manufactured by Daikin Industries, Ltd.) was used. Got

Example 3 0.5 g of the additive dispersion (3) obtained in Reference Example 3 was used in place of the additive dispersion (1) in Example 1,
0.01P instead of 02Pa · s silicone oil
An electrorheological fluid (3) of the present invention was obtained in the same manner as in Example 1 except that 69.5 g of an as mineral electric insulating oil (manufactured by Cosmo Oil Co., Ltd., high pressure insulating oil) was used.

Comparative Example 1 30 g of the dispersed phase particles (1) in Example 1 were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to obtain a water content of 2.
After adjusting to 0% by weight, 0.02 Pa · s of silicone oil (KF96-20c manufactured by Shin-Etsu Chemical Co., Ltd.
s) Mixed and dispersed in 70 g to obtain an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (1)).

Comparative Example 2 30 g of the dispersed phase particles (1) in Example 1 were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to obtain a water content of 2.
After adjusting to 0% by weight, it is mixed and dispersed in 70 g of 0.01 Pa · s mineral-based electric insulating oil (manufactured by Cosmo Oil Co., Ltd., high-pressure insulating oil), and an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (2)). ) Got.

Comparative Example 3 30 g of the dispersed phase particles (1) in Example 1 were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to obtain a water content of 2.
Adjusted to 0% by weight. Spherical silica particles of comparative additive (1) (made by Nippon Shokubai Co., Ltd., average particle size 1.0 μm)
1.5 g of silicone oil (KF96-20cs, manufactured by Shin-Etsu Chemical Co., Ltd.) was added uniformly to a dispersion medium obtained by adding 68.8 g, and an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (3)). ) Got.

Comparative Example 4 30 g of the dispersed phase particles (1) in Example 1 were dried at 150 ° C. for 3 hours and allowed to absorb moisture in the atmosphere to obtain a water content of 2.
After adjusting to 0% by weight, it was mixed and dispersed in 68 g of a mineral type electrical insulating oil (manufactured by Cosmo Oil Co., Ltd., high pressure insulating oil) in which 2.0 g of the comparative additive (1) obtained in Reference Example 4 was dissolved. An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (4)) was obtained.

Example 4 The electrorheological fluids (1) to (3) and comparative fluid (1) of the present invention obtained in Examples 1 to 3 and Comparative Examples 1 to 4
For each of (4), the viscosity at 25 ° C. when no electric field was applied was measured under shear conditions of shear rates of 3.3 / s and 33 / s, and the Ti value was calculated according to the above equation (1).
Next, each electrorheological fluid is 150 mm in height and 15 in diameter.
A 100 mm test tube was filled up to 100 mm from the bottom, sealed, and then allowed to stand at room temperature to trace the precipitation state of dispersed phase particles. The height from the bottom of the test tube of the precipitation layer generated by the precipitation of the dispersed phase particles in the electrorheological fluid was measured one day and one week after standing, and the dispersion stability of the electrorheological fluid was evaluated. Furthermore, put 50 ml of each electrorheological fluid into a 100 ml container, seal it tightly, and allow it to stand for 1 month, then 3 minutes per minute
It was rotated at a speed of 0 rotation, and the total number of rotations required to return to the original uniform state was measured to evaluate redispersibility. The results are shown in Table 1.

Further, the average particle diameter X of the additives (1) to (3) obtained in Reference Examples 1 to 3 and the comparative additive (1)
B is measured in an electrically insulating oil used when preparing an electrorheological fluid using a particle size distribution meter Shimadzu Laser Diffraction Particle Size Distribution Analyzer SALD-1000) manufactured by Shimadzu Corporation,
The electrorheological fluids (1) to (3) and the comparative fluid (3) are
It was evaluated whether Expression (2) was satisfied. The results are shown in Table 1.
Shown in.

[0225]

[Table 1]

Further, each of the electrorheological fluids was placed in a rotary viscometer with a coaxial electric field, and an AC external electric field of 4000 V / m was applied under the conditions of an inner / outer tube gap of 1.0 mm, a shear rate of 33 / s, and 25 ° C.
The shear stress value (initial value) when m (frequency: 50 Hz) was applied and the current density (initial value) flowing at that time were measured. Furthermore, after continuously operating the viscometer at 25 ° C. for 3 days while applying an external electric field of 4000 V / mm,
Shear stress values (values after 3 days) and current densities (values after 3 days) were measured to examine the temporal stability of the electrorheological fluid. The results are shown in Table 2.

[0227]

[Table 2]

As is clear from Table 1, the electrorheological fluids (1) to (3) of the present invention have a structural viscosity of η ₂ of 0.5 Pa · s or less and a significant Ti value. Since it was provided, it was excellent in dispersion stability and redispersibility. However, the comparison fluids (1) to (2) are η ₂
Was 0.5 Pa · s or less, but structural viscosity was not imparted, and the dispersion stability and redispersibility were poor. on the other hand,
Comparative fluids (3) and (4) were inferior in dispersion stability and redispersibility because the Ti value was not within the appropriate range. Further, as is clear from Table 2, the electrorheological fluids (1) to (1) of the present invention are
(3) maintained good shear stress characteristics and current characteristics as in Comparative Fluids (1) and (2).

Reference Example 5 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 150 g of toluene, 1 g of benzoyl peroxide, and methoxypolyethylene glycol containing methacryloyl group (manufactured by Shin-Nakamura Chemical Co., Ltd.) 40 g of NK ester M-230G, average molecular weight of about 1100, and 60 g of methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight of about 5000) were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. . This was heated at 75 ° C. for 3 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (2) having an average molecular weight of 70,000.

350 g of isopropyl alcohol, 2 g of the polymer (2), 2 g of benzoyl peroxide and 50 g of styrene were added to a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, and nitrogen was added. And was stirred at room temperature for 30 minutes. 70 this
The polymerization reaction was carried out by heating at ℃ for 24 hours. 200 g of 0.02 Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, and then the volatile component was distilled off by drying under reduced pressure with an evaporator to obtain a polymer ( A silicone oil dispersion of additive (4) in which 2) was composited on the surface of polystyrene fine particles (content of additive (4) was 20% by weight, hereinafter referred to as additive dispersion (4)) was obtained.

Reference Example 6 200 ml of methanol and 100 ml of ion-exchanged water were mixed in a 300 ml flask, and silica gel fine particles (manufactured by Nippon Shokubai Co., Ltd., spherical, average particle diameter 1.5 μm) were added thereto.
m) 100 g was dispersed. 7 g of γ-methacryloxypropyltrimethoxysilane was added thereto and reacted at 70 ° C for 1 hour, the solvent was distilled off by heating, and the obtained reaction product was dried at 60 ° C under reduced pressure.

Toluene 300 m in a 500 ml flask
100 g of the above reaction product obtained by drying and adding 1 was dispersed. There, 1 g of azobisisobutyronitrile, methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight = about 5)
000) and 5 g of butyl methacrylate were dissolved and reacted at 70 ° C. for 5 hours. After completion of the reaction, the solvent is distilled off by heating under reduced pressure, and a polymer having an average molecular weight of 25,000 is complexed on the surface of the silica gel particles (5).
Got

Reference Example 7 200 ml of methanol and 100 ml of ion-exchanged water were mixed in a 300 ml flask, and silica gel fine particles (manufactured by Nippon Shokubai Co., Ltd., pearl-shaped, average particle size 1.5 μm) were mixed therein.
m) 100 g was dispersed. 7 g of γ-methacryloxypropyltrimethoxysilane was added thereto and reacted at 70 ° C. for 1 hour, the solvent was distilled off by heating, and the obtained reaction product was dried under reduced pressure at 60 ° C.

Toluene 300 m in a 500 ml flask
100 g of the above reaction product obtained by drying and adding 1 was dispersed. There, 1 g of azobisisobutyronitrile, methacryloyl group-containing polydimethylsiloxane (Cilaplane FM0721 manufactured by Chisso Corporation, average molecular weight = about 5)
000) and 5 g of diethylaminoethyl methacrylate were dissolved and reacted at 70 ° C. for 5 hours. After completion of the reaction, the solvent was distilled off by heating under reduced pressure to obtain an additive (6) in which a polymer having an average molecular weight of 25,000 was complexed on the surface of the silica gel fine particles.

Example 5 1.2 L of water was charged into a 3-liter 4-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, and Kuraray Poval PVA-205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) 8 After adding and dissolving 0.0 g of styrene, 270 g of styrene, 30 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene, 35% by weight of ethylstyrene, manufactured by Wako Pure Chemical Industries, Ltd.) and 8 g of azobisisobutyronitrile. Was added.
Then, the contents in the flask were dispersed at a stirring speed of 8000 rpm, and polymerization was carried out at 80 ° C. for 8 hours. The obtained solid matter was filtered off, washed thoroughly with water, and then dried at 80 ° C. for 12 hours using a hot air drier to obtain 291 g of a spherical crosslinked polymer (hereinafter referred to as crosslinked polymer (2)).

Next, 100 g of the crosslinked polymer (2) was charged into a 2-liter four-necked separable flask equipped with a stirrer, a thermometer and a dropping funnel, and 98% by weight of concentrated sulfuric acid 700
g to make a uniform dispersion. The temperature of the reaction mixture is 80
After the temperature was raised to 0 ° C., the mixture was heated and stirred at the same temperature for 24 hours to carry out a sulfonation reaction. Then, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water. 10% by weight of the solid obtained
After being neutralized with 500 ml of an aqueous sodium hydroxide solution, it was thoroughly washed with water. Then, using a vacuum dryer, at 10 ℃ 10
After drying for an hour, polystyrene-based polymer particles containing sulfonic acid groups having an average particle diameter of 5 μm (hereinafter referred to as dispersed phase particles (2))
180 g was obtained. The anion dissociative group density of the dispersed phase particles (2) was 4.3 mg equivalent / g.

30 g of the dispersed phase particles (2) were dried at 150 ° C. for 3 hours to absorb moisture in the air to adjust the water content to 2.0% by weight. 4 g of the additive dispersion liquid (4) obtained in Reference Example 5 was added to the dispersed phase particles (2) as a silicone oil of 0.02 Pa · s (KF96- manufactured by Shin-Etsu Chemical Co., Ltd.).
20 cs) and fluorine-based oil (Daikin Kogyo Co., Ltd., Daifloyl # 1) 50 g were mixed and dispersed uniformly in a dispersion medium to obtain an electrorheological fluid (4) of the present invention.

Example 6 In place of the additive dispersion liquid (4) in Example 5, 0.5 g of the additive (5) obtained in Reference Example 6 was used and 0.02P
An electrorheological fluid (5) of the present invention was obtained in the same manner as in Example 5, except that the amount of the silicone oil as (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to 69.5 g. It was

Example 7 In place of the additive dispersant (4) in Example 5, 0.5 g of the additive (6) obtained in Reference Example 7 was used and 0.02P
An electrorheological fluid (6) of the present invention was obtained by the same method as in Example 5, except that the amount of the silicone oil a.s (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to 69.5 g. It was

Comparative Example 5 30 g of the dispersed phase particles (2) in Example 5 were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to obtain a water content of 2.
Adjusted to 0% by weight. This is a silicone oil of 0.02 Pa · s (KF96-20 manufactured by Shin-Etsu Chemical Co., Ltd.
cs) 70 g were mixed and dispersed to obtain a comparative electrorheological fluid (hereinafter referred to as comparative fluid (5)).

Comparative Example 6 30 g of the dispersed phase particles (2) in Example 5 were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to obtain a water content of 2.
Adjusted to 0% by weight. The average particle size is 0.007 μm
Powdered silica (AERO from Nippon Aerosil Co., Ltd.
SIL380) 1.8 g of silicone oil (Shin-Etsu Silicone KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.)
It was uniformly dispersed in a dispersion medium obtained by adding 68.2 g to obtain a comparative electrorheological fluid (hereinafter referred to as comparative fluid (6)).

Example 8 The electrorheological fluids (4) to (6) and the comparative fluid (5) of the present invention obtained in Examples 5 to 7 and Comparative Examples 5 to 6 were used.
For each of (6), viscosity η ₁ and η ₂ were obtained at shear rates of 3.3 / s and 33 / s at a temperature of 25 ° C. without applying an electric field, and Ti was calculated according to the above equation (1). The value was calculated. Next, the electrorheological fluid is placed at a height of 150 mm,
The test tube with a diameter of 15 mm was filled up to 100 mm from the bottom, sealed, and then left at room temperature to trace the precipitation state of the dispersed phase particles. The height from the bottom of the test tube of the precipitation layer generated by the precipitation of the dispersed phase particles in the electrorheological fluid was measured one day and one week after the standing, and the dispersion stability of the electrorheological fluid was evaluated. 50 ml of each electrorheological fluid is added to 100
The mixture was placed in a ml container, sealed, allowed to stand for 1 month, then rotated at a speed of 30 revolutions per minute for each container, and the total number of revolutions required until the original uniform state was restored was measured to evaluate redispersibility.

Further, the average particle diameter XB of the additives (4) to (6) obtained in Reference Examples 5 to 7 was measured by using a particle size distribution meter in the electrically insulating oil used when preparing the electrorheological fluid. And an electrorheological fluid prepared using an additive (4)
It was evaluated whether (6) satisfies the formula (2).

Further, each of the electrorheological fluids was put into a rotary viscometer with a coaxial electric field, and an AC external electric field 4000 was applied under the conditions of an inner / outer tube gap of 1.0 mm, a shear rate of 400 / s and a temperature of 25 ° C.
The shear stress value (initial value) when V / mm (frequency: 50 Hz) was applied and the current density (initial value) flowing at that time were measured. Further, after continuously operating the viscometer at 25 ° C. for 3 days with an external electric field of 4000 V / mm applied, shear stress value (value after 3 days) and current density (3
The value after day) was measured to examine the stability of the electrorheological fluid with time. The results are shown in Table 3.

[0245]

[Table 3]

As is clear from Table 3, the electrorheological fluids (4) to (6) of the present invention have a structure in which η ₂ is 0.5 Pa · s or less and a Ti value in a specific range is recognized. Since it was given viscosity, it was excellent in dispersion stability and redispersibility. On the other hand, the comparative fluid (5) was inferior in dispersion stability and redispersibility because the Ti value was small. The comparative fluid (6) was inferior in fluidity because η ₂ exceeded 0.5 Pa · s. Further, the electrorheological fluid of the present invention (4)
(6) maintained good shear stress characteristics and good current characteristics.

Reference Example 8 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 150 g of toluene, 1 g of azobisisobutyronitrile, and a methacryloyl group-containing poly (mer) as a silicone macromer (am). Dimethyl siloxane (Cilaso FM072 manufactured by Chisso Corporation
1, the average molecular weight = about 5000) 50g, and stearyl methacrylate 50g as a long-chain alkyl group-containing monomer (b-4) were charged, and at room temperature while blowing nitrogen 30
Stir for minutes. This was heated at 80 ° C. for 2 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (3).

350 g of isopropyl alcohol, 2.5 g of polymer (3), 1.5 g of azobisisobutyronitrile and polymerizability were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. 50 g of styrene as a monomer (α) was added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. 0.02 in this reaction solution
After 200 g of Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was dropped, volatile components were distilled off by drying under reduced pressure with an evaporator.
Silicone oil dispersion of composite (1) (composite (1)
Content of 20% by weight, hereinafter referred to as additive dispersion (7))
Got

Reference Example 9 In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 150 g of toluene, 1 g of azobisisobutyronitrile, and a methacryloyl group-containing polymethacrylate as a silicone macromer (am) were used. Dimethyl siloxane (Cilaso FM072 manufactured by Chisso Corporation
40 g of 1, average molecular weight = about 5000 and 60 g of dodecyl methacrylate as a long chain alkyl group-containing monomer (b-4) were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 75 ° C. for 3 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (4).

350 g of isopropyl alcohol, 2 g of polymer (4), 1 g of azobisisobutyronitrile, and a polymerizable monomer (in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube) As α), add 50 g of styrene and blow it with nitrogen for 30 at room temperature.
Stir for minutes. This was heated at 70 ° C. for 15 hours to carry out a polymerization reaction. Silicone oil of 0.02 Pa · s (KF96-20 manufactured by Shin-Etsu Chemical Co., Ltd.) was added to this reaction liquid.
After 200 g of cs) was dropped, the volatile component was distilled off by drying under reduced pressure with an evaporator to obtain a silicone oil dispersion of the composite (2) (content of the composite (2): 20% by weight; Liquid (8) was obtained.

Reference Example 10 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introducing tube, 200 g of toluene, 1 g of benzoyl peroxide, and a polymethysiloxane containing a methacryloyl group as a silicone macromer (am) ( 60 g of Cilaplane FM0725 manufactured by Chisso Corporation, average molecular weight = about 10,000) and 40 g of dodecylstyrene as a long-chain alkyl group-containing monomer (b-4) were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 75 ° C. for 20 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (5).

350 g of isopropyl alcohol, 1.5 g of polymer (5), 2 g of benzoyl peroxide and polymerizable monomer (α) were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. ), 50 g of styrene was added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 75 ° C. for 20 hours to carry out a polymerization reaction. Silicone oil of 0.02 Pa · s (KF96-20c manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the reaction solution.
s) After dropping 200 g, the volatile matter was distilled off by drying under reduced pressure with an evaporator to obtain a silicone oil dispersion liquid of the composite (3) (content of the composite (3): 20% by weight, hereinafter additive dispersion). Liquid (9) was obtained.

Reference Example 11 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 200 g of toluene, 1 g of benzoyl peroxide, and tris (trimethylsiloxy) silylpropyl as a silicone macromer (am). Methacrylate (X-22-50 manufactured by Shin-Etsu Chemical Co., Ltd.
02, average molecular weight = about 422) 65 g, 25 g of dodecyl acrylate as a long chain alkyl group-containing monomer (b-4)
And acrylonitrile 1 as other monomer (d)
0 g was added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (6).

Hexane (3) was added to a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introducing tube.
50 g, 2.5 g of polymer (6), 1 g of azobisisobutyronitrile, 40 g of methyl methacrylate and 10 g of benzyl methacrylate as polymerizable monomers (α) were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. did. This was heated at 70 ° C. for 20 hours to carry out a polymerization reaction. 200 g of 0.02 Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction solution, and then the volatile component was distilled off by drying under reduced pressure with an evaporator to obtain a complex (4). To obtain a silicone oil dispersion (content of composite (4): 20% by weight, hereinafter referred to as additive dispersion (10)).

Reference Example 12 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 150 g of toluene, 1 g of azobisisobutyronitrile, and a methacryloyl group-containing poly (mer) as a silicone macromer (am). Dimethyl siloxane (Cilaso FM072 manufactured by Chisso Corporation
5, average molecular weight = about 5000) 50 g, long-chain alkyl group-containing monomer (b-4) dodecyl methacrylate 45
g and methacrylic acid 5 g as other monomer (d)
Was charged, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 80 ° C. for 2 hours to carry out a polymerization reaction. Furthermore, 5 g of glycidyl methacrylate and 1 g of dimethylaminoethanol were added, and the reaction was carried out at 100 ° C. for 5 hours. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (7).

350 g of isopropyl alcohol, 2.5 g of polymer (7), 1.5 g of azobisisobutyronitrile and a polymerizable compound were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. 50 g of styrene as a monomer (α) was added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. 0.02 in this reaction solution
After 200 g of Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was dropped, volatile components were distilled off by drying under reduced pressure with an evaporator.
Silicone oil dispersion of composite (5) (composite (5)
Content of 20% by weight, hereinafter referred to as additive dispersion (11).

Reference Example 13 150 ml of methanol and 50 ml of ion-exchanged water were charged into a 300 ml flask, and 10 g of spherical silica particles (manufactured by Nippon Shokubai Co., Ltd., true sphere, average particle diameter 1 μm) were dispersed. 5 g of γ- (methacryloxypropyl) trimethoxysilane was added thereto and reacted at 40 ° C. for 2 hours to introduce a methacryloyl group on the surface of the spherical silica particles. Then, the solvent was distilled off under reduced pressure with an evaporator and dried at 50 ° C. using a vacuum dryer to obtain a reaction product. Then 200 ml
150 ml of toluene was placed in the flask described above, and 15 g of the obtained reaction product was dispersed. There, 0.1 g of azobisisobutyronitrile, polymethysiloxane containing a methacryloyl group as a silicone-based macromer (am) (Silaprene FM0721 manufactured by Chisso Corporation, average molecular weight = about 5000, silicon content = 36%). 6 g and 0.9 g of dodecyl methacrylate as the long-chain alkyl group-containing monomer (b) were dissolved and reacted at 70 ° C. for 5 hours.
After 66 g of 0.02 Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was dropped into this reaction solution, volatile components were distilled off under reduced pressure with an evaporator to obtain a silicone oil dispersion liquid of the composite (6). (Content of composite (6) 20% by weight, hereinafter referred to as additive dispersion (12))
Got

Reference Example 14 480 ml of water was charged into a 1-liter 4-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, and 6.4 g of Kuraray Poval PVA-205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was added. After addition and dissolution, 110 g of methyl methacrylate, industrial divinylbenzene (Wako Pure Chemical Industries, Ltd., divinylbenzene 5
5% by weight, a mixture of 35% by weight of ethylstyrene, etc.) 10
and a mixture of 3 g of azobisisobutyronitrile was added. Then, using a bio mixer, 2000
Disperse the contents in the flask at a stirring speed of 0 rpm, and
Polymerization was carried out at 0 ° C. for 8 hours. The obtained solid matter was filtered off, washed thoroughly with water, and then dried at 80 ° C. for 12 hours using a hot air drier to obtain 115 g of spherical crosslinked polymer fine particles.

Then, the above-mentioned crosslinked polymer fine particles 1 were placed in a 1-liter three-necked separable flask equipped with a stirrer and a thermometer.
00 g was charged, and 400 g of a 10 wt% sodium hydroxide methanol solution was added to form a uniform dispersion liquid. After raising the temperature of the reaction mixture to 70 ° C., heating at the same temperature for 24 hours
The mixture was stirred to carry out a saponification reaction. Then, the reaction mixture was filtered and washed with water. The obtained solid is treated with 2N hydrochloric acid 500m
After being dispersed in 1 l, it was thoroughly washed with water. Then, it was dried at 80 ° C. for 10 hours using a vacuum drier to obtain 95 g of carboxylic acid group-containing polymer particles insoluble in silicone insulating oil and having an average particle diameter of 2 μm.

150 ml of toluene in a 300 ml flask
10 g of carboxylic acid group-containing polymer particles synthesized above were dispersed therein. 5 g of glycidyl methacrylate and 0.75 g of dimethylaminoethyl methacrylate were added thereto and reacted at 40 ° C. for 5 hours to introduce a methacryloyl group on the surface of the polymer particles. Next, 0.1 g of azobisisobutyronitrile and polydimethylsiloxane containing a methacryloyl group as a silicone-based macromer (am) (Cilaplane FM0 manufactured by Chisso Corporation)
721, average molecular weight = about 5000 (0.75 g) and 0.5 g of stearyl methacrylate as a long-chain alkyl group-containing monomer (b-4) were added and dissolved, and the mixture was reacted at 70 ° C for 5 hours. Silicone oil of 0.02 Pa · s (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) 6 was added to the reaction liquid.
After dropping 8 g, the volatile matter was distilled off under reduced pressure by an evaporator to obtain a silicone oil dispersion liquid of the composite (7) (content of the composite (7) 20% by weight, hereinafter additive dispersion (13)).
I got).

Reference Example 15 350 g of isopropyl alcohol, 2.5 g of polyvinylpyrrolidone, 1 g of azobisisobutyronitrile and a polymerizable monomer were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introducing tube. 50 g of styrene was added as a body (α), and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. Silicone oil of 0.02 Pa · s (KF96- manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the reaction solution.
20 cs) 200 g was dropped, and then the volatile matter was distilled off by drying under reduced pressure with an evaporator, and a silicone oil dispersion liquid of polystyrene particles (comparative additive (2)) (polystyrene particle content 20% by weight; An additive dispersion liquid (2) was obtained.

Reference Example 16 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 200 g of toluene, 3 g of azobisisobutyronitrile, and a methacryloyl group-containing polymethacrylate as a silicone macromer (am) were used. Dimethyl siloxane (Cilaso FM072 manufactured by Chisso Corporation
1, average molecular weight = about 5000) 50 g and methyl methacrylate 5 g as other polymerized monomer (d) were added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 3 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (8).

350 g of isopropyl alcohol, 2 g of polymer (8), 2 g of azobisisobutyronitrile and a polymerizable monomer (in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube) 50 g of styrene was added as α), and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. Silicone oil of 0.02 Pa · s (KF96- manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the reaction solution.
20 cs) 200 g was added dropwise, and then the volatile matter was distilled off by drying under reduced pressure with an evaporator, and the silicone oil dispersion of the comparative additive (3) (content of the comparative additive (3) was 20% by weight. An additive dispersion liquid (3) was obtained.

Reference Example 17 To a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 200 g of toluene, 1 g of azobisisobutyronitrile, and a methacryloyl group-containing polymethacrylate as a silicone macromer (am) were used. Dimethyl siloxane (Cilaso FM072 manufactured by Chisso Corporation
1, average molecular weight = about 5000) 5g and long-chain alkyl group-containing monomer (b-4) dodecyl methacrylate 9
5 g was added, and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. After completion of the reaction, the solvent was distilled off by heating under reduced pressure with an evaporator to obtain an oily polymer (9).

350 g of isopropyl alcohol, 2.0 g of polymer (9), 1 g of azobisisobutyronitrile and a polymerizable monomer were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube. 50 g of styrene was added as a body (α), and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This was heated at 70 ° C. for 24 hours to carry out a polymerization reaction. 200 g of 0.02 Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise to this reaction product, and the volatile components were then distilled off by drying under reduced pressure with an evaporator. A silicone oil dispersion of comparative additive (4) (content of comparative additive (4) 20% by weight, hereinafter referred to as comparative additive dispersion (4)) was obtained.

Reference Example 18 200 g of ion-exchanged water was placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
2 g of sodium dodecylsulfonate and g of sodium persulfate were added and dissolved. To this, a monomer component consisting of 47 g of styrene and 3 g of industrial divinylbenzene (a mixture of 55% by weight of divinylbenzene and 35% by weight of ethylstyrene manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the dispersing machine was blown with nitrogen. Was stirred at 20000 rpm for 2 minutes. This was heated at 70 ° C. for 3 hours and further heated at 90 ° C. for 4 hours to carry out a polymerization reaction. The reaction solution was heated under reduced pressure to remove water, and then dried in an air oven at 80 ° C. overnight to obtain crosslinked polymer particles (hereinafter referred to as comparative additive (5)).

Reference Example 19 To 20 g of the comparative additive dispersion liquid (2) prepared in Reference Example 15 was added 20 g of the polymer (3) synthesized in Reference Example 8 and mixed.
Dispersion was performed to obtain Comparative Additive Dispersion Liquid (6).

Reference Example 20 150 ml of methanol and 50 ml of deionized water were charged into a 300 ml flask, and 10 g of spherical silica particles (manufactured by Nippon Shokubai Co., Ltd., true sphere, average particle diameter 1 μm) were dispersed. 5 g of γ-methacryloxypropyltrimethoxysilane was added thereto and reacted at 40 ° C. for 2 hours to introduce a methacryloyl group on the surface of the spherical silica particles. Then, the solvent was distilled off under reduced pressure with an evaporator and dried at 50 ° C. using a vacuum dryer to obtain a reaction product. Then 200 ml
150 ml of toluene was placed in the flask described above, and 15 g of the obtained reaction product was dispersed. There, 0.1 g of azobisisobutyronitrile and a long-chain alkyl group-containing monomer (b
-4) Dissolve 10 g of dodecyl methacrylate to obtain 7
The reaction was carried out at 0 ° C for 5 hours. 0.02 Pa · s in this reaction solution
Silicone oil (KF9 manufactured by Shin-Etsu Chemical Co., Ltd.
6-20 cs) (66 g) was added dropwise, the volatile components were distilled off under reduced pressure with an evaporator, and the silicone oil dispersion liquid of the comparative additive (7) (content ratio of the comparative additive (7) was 20% by weight; Liquid (7) was obtained.

Reference Example 21 In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 567 g of isopropyl alcohol, 5 g of azobisisobutyronitrile, polydimethylsiloxane containing a methacryloyl group (Chisso Corporation). Made silaplane FM0725, average molecular weight = about 10
000, silicon content = 37%) 15 g, methacryloyl group-containing polyethylene glycol tetraethylene glycol (Blenmer 55 PET-8 manufactured by NOF CORPORATION)
00, degree of polymerization of polyethylene glycol = 10, degree of polymerization of polytetramethylene glycol = 5, average molecular weight = about 900, oxygen content = 31%, and 60 g of industrial divinylbenzene (manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene) 25 g of a mixture of 55 wt% and ethylene styrene 35 wt%) was added and the mixture was stirred at room temperature for 30 minutes while blowing nitrogen. This is heated at 65 ° C for 20 hours and further heated at 83 ° C.
Polymerization reaction was carried out by heating for 4 hours. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, which was 9
It was 8%. Silicone oil of 0.02 Pa · s (KF96-20c manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the reaction solution.
s) After dropping 392 g, the volatile matter was distilled off by heating under reduced pressure with an evaporator, and the silicone oil dispersion liquid of the comparative additive (8) (content ratio of the comparative additive (8) 2
0% by weight, hereinafter referred to as comparative additive dispersion (8), was obtained.

Reference Example 22 In a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 567 g of isopropyl alcohol, 5 g of azobisisobutyronitrile and polydimethylsiloxane containing methacryloyl group (Chisso Corporation). Made silaplane FM0725, average molecular weight = about 1
0000, silicon content = 37%) 60 g, methacryloyl group-containing polyethylene glycol tetraethylene glycol (Blenmer 55 PET- manufactured by NOF CORPORATION)
800, degree of polymerization of polyethylene glycol = 10, degree of polymerization of polytetramethylene glycol = 5, average molecular weight =
About 900, oxygen content = 31%) 30 g, and industrial divinylbenzene (manufactured by Wako Pure Chemical Industries, Ltd., a mixture of divinylbenzene 55% by weight, ethylstyrene 35% by weight, etc.) 10 g are charged, and nitrogen is blown at room temperature. Stir for 30 minutes. This is heated at 65 ° C for 20 hours and further heated at 83 ° C.
Polymerization reaction was carried out by heating for 4 hours. The solid content of the obtained reaction solution was measured to measure the polymerization rate of the monomer, which was 9
It was 8%. Silicone oil of 0.02 Pa · s (KF96-20c manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the reaction solution.
s) After dropping 392 g, the volatile matter was distilled off by heating under reduced pressure with an evaporator, and the silicone oil dispersion liquid of the comparative additive (9) (content ratio of the comparative additive (9) was 2).
0% by weight, hereinafter referred to as comparative additive dispersion (9), was obtained.

Example 9 1.2 L of water was charged into a 3-liter four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, and 16.0 g of Kuraray Poval PVA-205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was charged. After the addition and dissolution of styrene, 30 g of styrene, 30 g of industrial divinylbenzene (a mixture of Wako Pure Chemical Industries, Ltd., 55 wt% of divinylbenzene, 35 wt% of ethylene styrene, etc.) and 8 g of azobisisobutyronitrile. Was added. Then, the contents in the flask were dispersed at a stirring speed of 7,000 rpm, and polymerization was carried out at 80 ° C. for 8 hours. The obtained solid matter was separated by filtration, washed thoroughly with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain 289 g of a spherical crosslinked polymer (hereinafter referred to as crosslinked polymer (3)).

Then, 200 g of the crosslinked polymer (3) was charged in a 2-liter four-neck separable flask equipped with a stirrer, a thermometer and a dropping funnel, and 98% by weight of concentrated sulfuric acid 140
0 g was added to make a uniform dispersion. After raising the temperature of the reaction mixture to 80 ° C., the mixture was heated and stirred at the same temperature for 24 hours to carry out a sulfonation reaction. Then, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water. The obtained solid was neutralized with 1000 ml of a 10 wt% sodium hydroxide aqueous solution, and then thoroughly washed with water. Then, using a vacuum dryer,
After drying at 10 ° C. for 10 hours, a sulfonic acid group-containing polystyrene polymer particle having an average particle diameter of 6 μm (hereinafter referred to as dispersed phase particle (1
2)) was obtained. The density of the anion-dissociating groups of the dispersed phase particles (3) was 4.2 mg equivalent / g.

30 g of the dispersed phase particles (3) were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to adjust the water content to 2.0% by weight. Then, the additive obtained in Reference Example 8 was used. 4 g of the dispersion liquid (7) was added to 0.02 Pa · s of silicone oil (KF96-20c manufactured by Shin-Etsu Chemical Co., Ltd.).
s) Evenly dispersed in the dispersion medium obtained by adding 66 g to obtain an electrorheological fluid (7) of the present invention.

Example 10 3 g of the additive dispersion liquid (8) obtained in Reference Example 9 was used in place of the additive dispersion liquid (7) in Example 9 and 0.02
0.01 Pa ・ instead of Pa ・ s silicone oil
s silicone oil (KF manufactured by Shin-Etsu Chemical Co., Ltd.
The electrorheological fluid (8) of the present invention was obtained by the same method as in Example 9 except that 67 g of 96-10 cs) was used.

Example 11 5 g of the additive dispersion (9) obtained in Reference Example 10 was used in place of the additive dispersion (7) in Example 9, and silicone oil (KF96- manufactured by Shin-Etsu Chemical Co., Ltd.) was used. 20
An electrorheological fluid (9) of the present invention was obtained in the same manner as in Example 9 except that the amount of cs) used was changed to 65 g.

Example 12 5 g of the additive dispersion (10) obtained in Reference Example 11 was used in place of the additive dispersion (7) in Example 9, and silicone oil (KF96- manufactured by Shin-Etsu Chemical Co., Ltd.) was used. Two
The electrorheological fluid (10) of the present invention was obtained in the same manner as in Example 9 except that the amount of 0 cs) used was changed to 65 g.

Example 13 5 g of the additive dispersion (11) obtained in Reference Example 12 was used in place of the additive dispersion (7) in Example 9, and silicone oil (KF96- manufactured by Shin-Etsu Chemical Co., Ltd.) was used. Two
The electrorheological fluid (11) of the present invention was obtained by the same method as in Example 9 except that the amount of 0 cs) used was changed to 65 g.

Example 14 1.2 L of water was charged into a 3-liter 4-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer, and Kuraray Poval PVA-205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) 16 After adding and dissolving 0.0 g, 270 g of styrene and divinylbenzene for industrial use (manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene 55
% Mixture of ethylene styrene 35% by weight) 30
g and 8 g of azobisisobutyronitrile were added. Then, the contents in the flask were dispersed at a stirring speed of 2000 rpm, and polymerization was carried out at 80 ° C. for 8 hours.
The obtained solid matter was filtered off, washed thoroughly with water, and dried at 80 ° C. for 12 hours using a hot air drier to obtain 293 g of a spherical crosslinked polymer (hereinafter referred to as crosslinked polymer (4)).

Next, 100 g of the crosslinked polymer (4) was charged into a 2-liter 4-neck separable flask equipped with a stirrer, a thermometer, and a dropping funnel, and 98% by weight of concentrated sulfuric acid 700 was added.
g was added to form a uniform dispersion liquid. Increase the temperature of the reaction mixture to 8
After raising the temperature to 0 ° C., the mixture was heated and stirred at the same temperature for 24 hours to carry out a sulfonation reaction. Then, the reaction mixture was poured into water at 0 ° C., filtered, and washed with water. The obtained solid was neutralized with 500 ml of a 10 wt% sodium hydroxide aqueous solution, and then thoroughly washed with water. Then, use a vacuum dryer at 80 ° C for 1
After drying for 0 hour, 173 g of sulfonic acid group-containing polystyrene polymer particles (hereinafter referred to as dispersed phase particles (4)) having an average particle diameter of 2.5 μm were obtained. The density of the anion-dissociating groups of the dispersed phase particles (4) was 4.1 mg equivalent / g.

30 g of the dispersed phase particles (4) were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to adjust the water content to 2.0% by weight. Then, the additive obtained in Reference Example 13 was added. 7 g of the dispersion liquid (12) was added to 0.02 Pa · s of silicone oil (KF96-2 manufactured by Shin-Etsu Chemical Co., Ltd.).
0 cs) and dispersed in the dispersion medium obtained by adding 63 g to obtain an electrorheological fluid (12) of the present invention.

Example 15 This example was prepared in the same manner as in Example 14 except that 4 g of the additive dispersion (13) obtained in Reference Example 14 was used instead of the additive dispersion (12) in Example 14. An electrorheological fluid (13) of the invention was obtained.

Example 16 30 g of zeolite particles (zeolite manufactured by Sigma Co., average particle diameter 3 μm, hereinafter referred to as dispersed phase particles (5))
Was dried at 150 ° C. for 3 hours, then moisture in the air was absorbed to adjust the water content to 10.0%, and then 4 g of the additive dispersion liquid (7) obtained in Reference Example 8 was added to 0.02 Pa. s silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.
-20 cs) was uniformly dispersed in the dispersion medium obtained by adding 66 g to obtain an electrorheological fluid (14) of the present invention.

Comparative Example 7 30 g of the dispersed phase particles (3) in Example 9 were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to obtain a water content of 2.0.
After adjusting to the weight%, 0.02 Pa · s of silicone oil (KF96-20c manufactured by Shin-Etsu Chemical Co., Ltd.
s) Mixed and dispersed in 70 g to obtain an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (7)).

Comparative Example 8 30 g of the dispersed phase particles (3) in Example 9 were dried at 150 ° C. for 3 hours, and moisture in the atmosphere was absorbed to obtain a water content of 2.0.
After adjusting to the weight%, 0.01 Pa · s silicone oil (KF96-10cs manufactured by Shin-Etsu Chemical Co., Ltd.)
The mixture was dispersed in 70 g to obtain an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (8)).

Comparative Example 9 30 g of the dispersed phase particles (4) in Example 14 were added at 150 ° C.
After being dried for 3 hours at room temperature, moisture in the atmosphere is absorbed to obtain a water content of 2.
After adjusting to 0% by weight, 0.02 Pa · s of silicone oil (KF96-20c manufactured by Shin-Etsu Chemical Co., Ltd.
s) Mixed and dispersed in 70 g to obtain a comparative electrorheological fluid (hereinafter referred to as comparative fluid (9)).

Comparative Example 10 4 g of the comparative additive dispersion (2) obtained in Reference Example 15 was used in place of the additive dispersion (7) in Example 9,
Silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (10)) was obtained in the same manner as in Example 9 except that the amount of -20 cs) used was changed to 66 g.

Comparative Example 11 4 g of the comparative additive dispersion (3) obtained in Reference Example 16 was used in place of the additive dispersion (7) in Example 9,
Silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (11)) was obtained in the same manner as in Example 9 except that the amount of -20 cs) used was changed to 66 g.

Comparative Example 12 5 g of the comparative additive dispersion (4) obtained in Reference Example 17 was used in place of the additive dispersion (7) in Example 9,
Silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (12)) was obtained in the same manner as in Example 9 except that the amount of -20 cs) used was changed to 65 g.

Comparative Example 13 1 g of the comparative additive dispersion (5) obtained in Reference Example 18 was used in place of the additive dispersion (7) in Example 9,
Silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (13)) was obtained in the same manner as in Example 9 except that the amount of -20 cs) used was changed to 69 g.

Comparative Example 14 5 g of the comparative additive dispersion (6) obtained in Reference Example 19 was used in place of the additive dispersion (7) in Example 9,
Silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (14)) was obtained in the same manner as in Example 9 except that the amount of -20 cs) used was changed to 65 g.

Comparative Example 15 5 g of the comparative additive dispersion (7) obtained in Reference Example 20 was used in place of the additive dispersion (12) in Example 14, and a silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) was used. KF
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (15)) was obtained by the same method as in Example 14 except that the amount of 96-20 cs) used was changed to 65 g.

Comparative Example 16 30 g of the dispersed phase particles (5) in Example 16 were added at 150 ° C.
After drying for 3 hours at room temperature to absorb moisture in the air to adjust the water content to 10.0% by weight, 0.02 Pa · s silicone oil (KF96-20cs manufactured by Shin-Etsu Chemical Co., Ltd.)
The mixture was dispersed in 70 g to obtain an electrorheological fluid for comparison (hereinafter referred to as comparative fluid (16)).

Comparative Example 17 20 g of the comparative additive dispersion liquid (8) obtained in Reference Example 21 was used in place of the additive dispersion liquid (7) in Example 9,
Silicone oil (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.
An electrorheological fluid for comparison (hereinafter referred to as comparative fluid (17)) was obtained in the same manner as in Example 9 except that the amount of -20 cs) used was changed to 56 g.

Comparative Example 18 2.5 g of the comparative additive dispersion (8) obtained in Reference Example 21 was used in place of the additive dispersion (7) in Example 9, and silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) was used. KF
A comparative electrorheological fluid (hereinafter referred to as comparative fluid (18)) was obtained in the same manner as in Example 9 except that the amount of 96-20 cs) used was changed to 67.5 g.

Example 17 Electrorheological fluids (7) to (14) and comparative fluid (7) of the present invention obtained in Examples 9 to 16 and Comparative Examples 7 to 18
For each of (18) to (18), the viscosity η ₁ at a shear rate of 3.3 / s and 33 / s when no electric field was applied at a temperature of 25 ° C.
And η ₂ were measured, and the Ti value was calculated according to the above formula (1). Then, each electrorheological fluid is 150 mm high,
A test tube with a diameter of 15 mm was filled up to 100 mm from the bottom, sealed, and then left at room temperature to trace the precipitation state of dispersed phase particles. The height from the bottom of the test tube of the precipitation layer generated by the precipitation of the dispersed phase particles in the electrorheological fluid was measured one day and one week after the standing, and the dispersion stability of the electrorheological fluid was evaluated. Furthermore, 50 ml of each electrorheological fluid is added to 10
The mixture was placed in a 0 ml container, sealed, allowed to stand for 1 month, then rotated at a speed of 30 rpm for each container, and the total number of rotations required for returning to the original uniform state was measured to evaluate redispersibility. The average particle diameter XB of the composites (1) to (7) that are the additives obtained in Reference Examples 8 to 14 and the comparative additives (2) to (9) obtained in Reference Examples 15 to 22 are Electrorheological fluids (7) to (14) prepared by using an additive of the present invention and a comparative additive, which were measured by using a particle size distribution analyzer in an electrically insulating oil used for preparing an electrorheological fluid, and comparisons. It was evaluated whether the fluids (10) to (15), (17) and (18) satisfy the equation (2). The results are shown in Table 4.

Also, each of the electrorheological fluids was placed in a rotational viscometer with a coaxial electric field, and an AC external electric field 4000 was applied under the conditions of an inner / outer tube gap of 1.0 mm, a shear rate of 400 / s, and a temperature of 25 ° C.
The shear stress value (initial value) when V / mm (frequency: 50 Hz) was applied and the current density (initial value) flowing at that time were measured. Further, after continuously operating the viscometer at 25 ° C. for 3 days with an external electric field of 4000 V / mm applied, shear stress value (value after 3 days) and current density (3
The value after day) was measured to examine the stability of the electrorheological fluid with time. The results are shown in Table 4.

[0297]

[Table 4]

As is clear from Table 4, since the electrorheological fluids (7) to (14) of the present invention have η ₂ of 0.5 Pa · s or less and a significant Ti value, the structural viscosity is Since it was added, it was excellent in dispersion stability, redispersibility and fluidity. On the other hand, comparative fluids (7) to (9), (1
In 1) to (14), (16) and (18), since the Ti value was small, the dispersion stability or redispersibility was poor.
Comparative fluids (10), (15) and (17) were inferior in redispersibility and fluidity because η ₂ exceeded 0.5 Pa · s.

[0299]

INDUSTRIAL APPLICABILITY The electrorheological fluid of the present invention generates a large shear stress even when a relatively weak electric field is applied, and the current density flowing at that time is small. Excellent density stability over time, low initial viscosity when no electric field is applied, and dispersion stability (ability to maintain electrorheological fluid in a uniform state for a long time without precipitating or floating the dispersed phase). Especially excellent in redispersibility (the ability to reproduce the original uniform state with a simple external force after the dispersed phase has settled or floated and becomes non-uniform), so engine mounts, clutches, dampers, brakes, shock absorbers It can be effectively used for actuators, valves, etc.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // (C10M 169/04 107: 50 107: 38 149: 08 155: 02) C10N 20:02 20 : 06 Z 30:02 30:04 40:14

Claims (26)

[Claims] 1. An electrorheological fluid composed of a dispersed phase composed of dielectric particles and a dispersion medium composed of electrically insulating oil,
Shear rate 33 / measured at 25 ° C without applying an electric field
The viscosity of s in the sheared state is 0.5 Pa · s or less and the formula (1) is 0.01 Pa · s ≦ η ₁ −η ₂ ≦ 0.5 Pa · s (1) (wherein, η ₁ is Viscosity in a shear state at a shear rate of 3.3 / s measured at 25 ° C. without applying an electric field, η
₂ is the shear rate measured at 25 ° C without applying an electric field 3
It is a viscosity in a sheared state of 3 / s. ) An electrorheological fluid characterized by having a structural viscosity satisfying the condition (1). 2. The average particle diameter of the dielectric particles is 1 to 50 μm.
The electrorheological fluid according to claim 1, wherein 3. The electrorheological fluid according to claim 1, wherein the amount of the dispersion medium is 50 to 500 parts by weight per 100 parts by weight of the dispersed phase. 4. The electrorheological fluid according to claim 1, wherein the electrically insulating oil is a silicone-based insulating oil or a fluorine-based insulating oil. 5. The electrorheological fluid according to claim 1, which comprises a dispersed phase composed of dielectric particles, a dispersion medium composed of electrically insulating oil, and an additive. 6. The additive is particulate in electrically insulating oil,
The average particle diameter XB of the additive is the average particle diameter X of the dispersed phase particles.
The electrorheological fluid according to claim 5, wherein, when A is set, the condition of formula (2) 3/10 <XB / XA <3 (2) is satisfied. 7. The additive is substantially insoluble in an electrically insulating oil and has both a structural unit (A) containing a silicone component and a structural unit (B) containing a disperse phase adsorptive chain. Or the electrorheological fluid according to item 6. 8. The additive is 0.0 per 100 parts by weight of the dispersed phase.
The electrorheological fluid according to any one of claims 5 to 7, which is blended in an amount of 1 to 6 parts by weight. 9. A composite (1) obtained by compounding particles (I) substantially insoluble in electrically insulating oil and a polysiloxane-containing polymer (II) as an additive, wherein the polymer (II) )
Is represented by the general formula (3) as a structural unit (A) containing a silicone component. (In the formula, A represents -COO- or a phenylene group, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 1 to 6 carbon atoms, and R ^{3 to} R ¹³ are the same or different. Each represents an aryl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, a is an arbitrary integer, b is an integer of 0 to 200, and c and d are the same or different and 0 to Each of which represents an integer of 10.) as the polysiloxane-containing structural unit (A-1) and the dispersed-phase adsorptive chain-containing structural unit (B) represented by the general formula (4): (In the formula, B represents —COO— or a phenylene group, R ¹⁴ represents a hydrogen atom or a methyl group, R ¹⁵ represents an alkylene group having 2 to 4 carbon atoms, and R ¹⁶ represents a hydrogen atom or an alkyl group, e is an arbitrary integer, and f is an integer of 2 to 100.) An alkylene oxide chain-containing structural unit (B-1) represented by the general formula (5): The nitrogen-containing atom chain-containing structural unit (B-2) represented by and / or the general formula (6) (In the formula, E represents -COO- or a phenylene group, R ¹⁹ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkyl group having 1 to 30 carbon atoms, and i represents an arbitrary integer.) The electrorheological fluid according to any one of claims 5 to 8, which has at least one selected from the group consisting of the hydrocarbon chain-containing structural unit (B-3) represented. 10. The ratio of the polysiloxane-containing polymer (II) to the particles (I) substantially insoluble in the electrically insulating oil in the composite (1) is 0.
The electrorheological fluid according to claim 9, which is in the range of 1 to 100 parts by weight. 11. A composite (1) comprising particles (I) substantially insoluble in a polysiloxane-containing polymer (II) in an electrically insulating oil.
The electrorheological fluid according to claim 9 or 10, wherein the electrorheological fluid is compounded on the surface of. 12. A composite (1) comprising particles (I) substantially insoluble in an electrically insulating oil and a polysiloxane-containing polymer (II).
And 9 and are compounded via a chemical bond.
11. The electrorheological fluid according to any one of 11. 13. A polysiloxane-containing polymer (II)
Is represented by the general formula (7): (In the formula, F represents -COO- or a phenylene group, R ²¹ represents a hydrogen atom or a methyl group, and R ²² represents a carbon atom of 1).
The 6 alkylene group, showed R ²³ to R ³³ are the same or different aryl group, an alkyl group or an alkoxy group having 1 to 10 carbon atoms having 1 to 6 carbon atoms, respectively, j and k are the same or different 0 An integer of 10 to 1 is 0 to 200
Indicates the integers of. ) A silicon-based macromer (am) represented by the general formula (8) (In the formula, G represents -COO- or a phenylene group, R ³⁴ represents a hydrogen atom or a methyl group, and R ³⁵ represents 2 carbon atoms.
To alkylene groups, R ³⁶ is a hydrogen atom or an alkyl group, and m is an integer of 2 to 100. ) An alkylene oxide chain-containing monomer (bm-1) represented by the general formula (9): A nitrogen-containing atom chain-containing monomer (b-2) represented by and / or a general formula (10): (However Shikichu, K is shown a -COO- or a phenylene group, a hydrogen atom or a methyl group R39, R ⁴⁰ is C 1 -C
~ 30 alkyl groups are shown. ) At least one disperse phase adsorptive chain-containing monomer (b) selected from the hydrocarbon-containing monomers (b-3) represented by () is an essential component, and other monomers ( Monomer mixture (X) containing c)
The electrorheological fluid according to any one of claims 9 to 12, which is obtained by polymerizing. 14. A silicon-based macromer (am) and a dispersed phase adsorptive chain-containing monomer (b) in a monomer mixture (X).
14. The electrorheological fluid according to claim 13, wherein the ratio of 10 to 90% by weight of the silicon-based macromer (am) and 10 to 90% by weight of the dispersed phase adsorptive chain-containing monomer (b). 15. A particle (I) which is substantially insoluble in an electrically insulating oil, wherein the composite (1) is dispersion-polymerized with a polymerizable monomer (α) in the presence of a polysiloxane-containing polymer (II). The electrorheological fluid according to any one of claims 9 to 14, which is obtained by producing 16. The composite (1) is substantially insoluble in an electrically insulating oil by emulsion polymerization of a polymerizable monomer (α) in an aqueous medium in the presence of a polysiloxane-containing polymer (II). The electrorheological fluid according to any one of claims 9 to 14, which is obtained by producing particles (I). 17. The composite (1) comprises organic or inorganic fine particles having a polymerizable reactive group introduced therein as particles (I) substantially insoluble in electrical insulating oil, in the presence of the organic or inorganic fine particles. The electrorheological fluid according to any one of claims 9 to 14, which is obtained by polymerizing the monomer mixture (X) to produce the polysiloxane-containing polymer (II). 18. The additive polymer (1), wherein the additive is substantially insoluble in an electrically insulating oil and has a polysiloxane-containing polymer (III), wherein the polymer (III) contains a silicon component. As the structural unit (A), the polysiloxane-containing structural unit (A-1) represented by the general formula (3) and the dispersed phase adsorptive chain-containing structural unit (B) are represented by the general formula (11): (In the formula, L represents -COO- or a phenylene group, R ⁴¹ represents a hydrogen atom or a methyl group, and R ⁴² represents 8 carbon atoms.
~ 30 alkyl groups, S is an arbitrary integer. ) The structural unit (B-4) containing a long alkyl chain represented by the formula (4) is included in the electrorheological fluid according to any one of claims 5 to 8. 19. The additive polymer (1) is a composite (2) of particles (I) substantially insoluble in an electrically insulating oil and a polysiloxane-containing polymer (III), and the polymer (1) II
I) is a polysiloxane-containing structural unit (A-) represented by the general formula (3) as the silicone component-containing structural unit (A).
19. The electricity according to claim 18, which has a structural unit (B-4) containing a long-chain alkyl chain represented by the general formula (11) as the structural unit (B) containing 1) and a dispersed phase adsorptive chain. Viscous fluid. 20. 0.1 to 100 parts by weight of a polysiloxane-containing polymer (III) is blended per 100 parts by weight of particles (I) substantially insoluble in electrically insulating oil in the composite (2). The electrorheological fluid according to claim 19. 21. Particles (I) in which the composite (2) is substantially insoluble in the polysiloxane-containing polymer (III) in an electrically insulating oil.
21. The electrorheological fluid according to claim 19 or 20, which is a composite on the surface of. 22. Particles (I) substantially insoluble in electrically insulating oil
The electrorheological fluid according to any one of claims 19 to 20, wherein the polysiloxane-containing polymer (III) and the polysiloxane-containing polymer (III) are compounded via a chemical bond. 23. Polysiloxane-containing polymer (III)
Is a silicone-based macromer (am) represented by the general formula (7) and a general formula (12) (However, M is —COO— or a phenylene group, R ⁴³ is a hydrogen atom or a methyl group, and R ⁴⁴ is an alkyl group having 8 to 30 carbon atoms.) A long chain alkyl group-containing monomer (b -4) as an essential component, and is obtained by polymerizing a monomer mixture (Y) containing other monomer (d) as required, according to any one of claims 18 to 22. The electrorheological fluid described. 24. The silicone macromer (am) and the long chain alkyl group-containing monomer (b) in the monomer mixture (Y).
The electrorheological fluid according to claim 23, wherein the proportions of -4) are each in the range of 10 to 90% by weight. 25. Particles (I) substantially insoluble in the electrically insulating oil are obtained by dispersion-polymerizing the polymerizable monomer (α) in the presence of the polysiloxane-containing polymer (III) in the composite (2). The electrorheological fluid according to any one of claims 19 to 24, which is obtained by generating the electrorheological fluid. 26. The composite (2) comprises organic or inorganic fine particles having a polymerizable reactive group introduced therein as particles (I) substantially insoluble in an electrically insulating oil, and the composite (2) is used in the presence of the organic or inorganic fine particles. The electrorheological fluid according to any one of claims 19 to 24, which is obtained by polymerizing the monomer mixture (Y) to form a polysiloxane polymer (III).