JP2020158598A - Electro-viscous fluid - Google Patents

Abstract

To provide an electro-viscous fluid.SOLUTION: The electro-viscous fluid having polarized particles dispersed in an electrically insulating medium comprises at least one electrolyte dissolved or dispersed in the electrically insulating medium, wherein the polarized particles contain the electrolyte in particles, the polarized particles contain two or more particles having different concentrations of the electrolyte contained in the particles, and the polarized particles are composed of one or more particles having different average particle diameters represented by the following A to C (A: 0.50 to 2.50 μm, B: 3.00 to 5.00 μm, C: 5.50 to 15.00 μm).SELECTED DRAWING: Figure 2

Description

The present invention relates to electrorheological fluids.

An electrorheological fluid is a fluid whose apparent viscosity changes rapidly and reversibly in the presence of an applied electric field. Electrorheological fluids are generally solid dispersions that are finely divided into hydrophobic, electrically non-conductive oils. They have the ability to change their flow properties when exposed to an electric field, even when they become solid. When the electric field is removed, the fluid returns to its normal liquid state. Electrorheological fluids can be advantageously used in applications such as dampers where it is desirable to control the transmission of force by low power levels.

The characteristics required for the electrorheological fluid are mainly damping force and responsiveness, but in addition to these, there are a plurality of items including heat resistance, current density, damping force fluctuation characteristics, etc. An electrorheological fluid that is well-balanced within the permissible range of characteristics and has an excellent "total effect" is desired, and in particular, an electrorheological fluid that has both a high maximum shear stress and a low current density is desired.

Japanese Patent Application Laid-Open No. 2015-511634 (Patent Document 1) describes that an ERF (electrorheological fluid) having excellent electrorheological properties that can be used in a wide temperature range can be provided by adding an additive. ..

Japanese Patent Publication No. 2015-511634

With the electrorheological composition described in Patent Document 1, it has been difficult to obtain an electrorheological fluid having both a high maximum shear stress and a low current density.

Therefore, an object of the present invention is to provide an electrorheological fluid that can solve the above problems, that is, an electrorheological fluid having both a high maximum shear stress and a low current density.

As a result of diligent studies to solve the above problems, the present inventors have different concentrations of electrolytes contained in the polarized particles as the polarized particles in the electrorheological fluid in which the polarized particles are dispersed in the electrically insulating medium. It is possible to provide an electrorheological fluid having both high maximum shear stress and low current density by using more than one kind of particles and further forming one or more kinds of three kinds of particles having a specific average particle size. Find out and complete the invention.

That is, the present invention
[1] An electroviscous fluid in which polarization particles are dispersed in an electrically insulating medium, wherein the electrically insulating medium contains at least one kind of electrolyte dissolved or dispersed, and the polarization particles contain the electrolyte. The polarized particles contained therein include two or more kinds of particles having different concentrations of the electrolyte contained in the particles, and the polarized particles are different average particles represented by the following A to C. Electrolyte viscous fluid consisting of one or more particles with a diameter,
A: 0.50 to 2.50 μm
B: 3.00 to 5.00 μm
C: 5.50-15.00 μm
[2] The polarized particles are composed of two or more kinds of particles having different average particle diameters represented by the above A to C, and the two or more kinds of particles having different average particle diameters are different in the average particle diameter. The electrorheological fluid according to the above [1], wherein the concentrations of the electrolytes contained in the particles are different from each other.
[3] The polarized particles include particles having the average particle size indicated by C, and the concentration of the electrolyte contained in the particles having the average particle size indicated by C is the other average particle size. The electrorheological fluid according to the above [1] or [2], which is higher than the particles having.
[4] An electrorheological fluid that is a mixture of two or more of the electrorheological fluids according to any one of the above [1] to [3].
It is about.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an electrorheological fluid having both a high maximum shear stress and a low current density.
The electrorheological fluid of the present invention can be advantageously used as an electrorheological fluid for controlling a semi-active damper for an automobile.

It is a manufacturing flowchart which shows the manufacturing method of the fluid containing polyurethane particle as a polarization particle. It is a graph which shows the maximum shear stress and the current density in each fluid described in an Example.

The present invention will be described in more detail.
The electroviscous fluid of the present invention is an electroviscoud fluid in which polarized particles are dispersed in an electrically insulating medium, and the electrically insulating medium contains at least one kind of electrolyte dissolved or dispersed, and the polarized particles are: , The electrolyte is contained in the particles, and the polarized particles include two or more kinds of particles having different concentrations of the electrolyte contained in the particles, and the polarized particles are the following A to C. It is characterized by consisting of one or more of the particles having different average particle diameters shown.
A: 0.50 to 2.50 μm
B: 3.00 to 5.00 μm
C: 5.50-15.00 μm

Electrically insulating media that can be used in the present invention include, for example, paraffin (eg n-nonene), olefins [eg l-nonene, (cis, trans) -4-nonene] and aromatic hydrocarbons (eg xylene). Liquid hydrocarbons and silicone oils such as polydimethylsiloxane and liquid methylphenylsiloxane having a viscosity of 3 to 300 mPa · s. A preferred electrically insulating medium is silicone oil. The electrically insulating medium can be used alone or in combination with other electrically insulating media. The freezing point of the electrically insulating medium is preferably less than −30 ° C., and the boiling point is preferably 150 ° C. or higher.

Examples of the electrolyte that can be used in the present invention include salts of metals such as lithium, zinc, chromium, copper, nickel, cobalt, iron, manganese, and tungsten, such as halides, and preferably chlorides of the above metals. Be done.
In particular, lithium chloride, zinc chloride and mixtures thereof are preferred.

Examples of the polarized particles that can be used in the present invention include particles made of an organic polymer, and examples of the organic polymer include polyurethane, polyamide, polyimide, polyester, and the like, and polyurethane is preferable.

The polyurethane particles that can be used as the polarization particles will be described.
As a polyol that can be used to obtain polyurethane particles,
Ethylene glycol, diethylene glycol, propylene glycol, 1,4-butylene glycol, dihydroxydiphenylpropane, glycerin, hexanetriol, trimethylpropane, pentaerythritol, sorbitol, sucrose, dipropylene glycol, dihydroxydiphenylmethane, dihydroxydiphenyl ether, dihydroxybiphenyl, hydroquinone, Resolcin, naphthalenediol, aminophenol, aminonaphthol, phenolformaldehyde condensate, fluoroglucolcin, methyldiethanolamine, ethyldiisopropanolamine, triethanolamine, ethylenediamine, hexamethylenediamine, bis (p-aminocyclohexane), tolylene diamine, diphenylmethanediamine Polyether polyol obtained by adding one or more of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. to naphthalenediamine, etc.
Ester glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,3- or 1,4-butylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, decamethylene glycol, bisphenol A, bisphenol F, 1 such as ethylene oxide such as p-xylylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, glycerin, trimethylpropane, hexanetriol, pentaerythlit, propylene oxide, butylene oxide, styrene oxide adduct, etc. Species or two or more and one or two such as malonic acid, maleic acid, succinic acid, adipic acid, glutaric acid, pimeric acid, sebacic acid, oxalic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, etc. Polyol polyols from seeds or more, or polyols obtained by ring-opening polymerization of cyclic esters such as propiolactone, butyrolactone, and caprolactone; further, polyester polyols produced from the above polyols and cyclic esters, and the above polyols, dibasic acids, and cyclics. Polyol polyols made from 3 types of esters,
1,2-Polybutadiene polyols, 1,4-polybutadiene polyols, polychloroprene polyols, butadiene-acrylonitrile copolymer polyols, polydimethylsiloxane dicarbinol, polytetramethylene ether glycols and ricinolic acid esters such as castor oil, said above. A polymer polyol obtained by graft-polymerizing an ethylenically unsaturated compound such as acrylonitrile, styrene, or methyl methacrylate with a polyether polyol or a polyester polyol.
Etc., but a polyether polyol is preferable.

Examples of the isocyanate that can be used to obtain polyurethane particles include toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and methyl isocyanate.

The polyurethane particles are preferably reacted with the above-mentioned polyol and the above-mentioned isocyanate so that the NCO / OH equivalent ratio is 0.6 to 1.0.

The polarized particles contain an electrolyte in the particles, and the polarized particles include two or more kinds of particles having different concentrations of the electrolyte contained in the particles.
Examples of the electrolyte include salts of metals such as lithium, zinc, chromium, copper, nickel, cobalt, iron, manganese, and tungsten, such as halides, and preferably chlorides of the metals.
In particular, lithium chloride, zinc chloride and mixtures thereof are preferred.

Examples of the two or more types of particles having different electrolyte concentrations include particles having a low electrolyte concentration (hereinafter, also referred to as low concentration particles) and particles having a high electrolyte concentration (hereinafter, also referred to as high concentration particles). ) And particles containing no electrolyte (hereinafter, also referred to as non-concentration particles) and the like.
Here, as the particles having a low concentration of electrolyte (particles having a low concentration), the amount of metal ions contained in the polarized particles measured by ICP-MS is in the range of 0.01 ppm or more and less than 750.00 ppm, preferably 10 ppm or more and 750 ppm. Particles in the range of less than 00 ppm can be mentioned, and as particles having a high electrolyte concentration (particles having a high concentration), the amount of metal ions contained in the polarized particles measured by ICP-MS is in the range of 750.00 ppm or more and 1500.00 ppm or less. , Preferably, particles in the range of 800.00 ppm or more and 1500.00 ppm or less can be mentioned.
Further, the amount of metal ions in the particles containing no electrolyte (non-concentration particles) is substantially 0 ppm.

When two or more kinds of electrolytes are mixed and used as the electrolyte, the above-mentioned amount of metal ions means the total amount of metal ions.
For example, when a mixture of lithium chloride and zinc chloride is used as the electrolyte, the total amount of lithium ions and zinc ions in the low-concentration particles is in the range of 0.01 ppm or more and less than 750.00 ppm, preferably 10 ppm or more and 750.00 ppm. The total amount of lithium ion and zinc ion in the high-concentration particles is in the range of 750.00 ppm or more and 1500.00 ppm or less, preferably in the range of 800.00 ppm or more and 1500.00 ppm or less, and the non-concentration particles. The total amount of lithium ion and zinc ion in the above is substantially 0 ppm.

The polarized particles that can be used in the present invention consist of one or more of the particles having different average particle diameters represented by the following A to C.
A: 0.50 to 2.50 μm
B: 3.00 to 5.00 μm
C: 5.50-15.00 μm
Here, the above-mentioned average particle diameter indicates the value of the particle diameter D50 (median diameter) of the particle size distribution (volume basis) obtained by the laser diffraction scattering method.
The average particle size of the particles A is preferably in the range of 0.80 to 2.40 μm, more preferably in the range of 0.99 to 2.30 μm.
The average particle size of the particle B is preferably in the range of 3.00 to 4.50 μm, more preferably in the range of 3.20 to 4.00 μm.
The average particle size of the particles C is preferably in the range of 6.00 to 13.00 μm, more preferably in the range of 8.00 to 10.00 μm.

Since the particles A to C include low-concentration particles, high-concentration particles, and non-concentration particles, respectively, nine types of particles represented by the following (I) to (IX) can be considered. The polarized particles that can be used in the electrorheological fluid of the present invention will be composed of at least two or more of these particles.
(I) Particle A having a low concentration of electrolyte
(II) Particle B having a low concentration of electrolyte
(III) Particles with low electrolyte concentration C
(IV) Particle A having a high concentration of electrolyte
(V) Particles with a high concentration of electrolyte B
(VI) Particles with a high concentration of electrolyte C
(VII) Electrolyte-free particles A
(VIII) Electrolyte-free particles B
(IX) Electrolyte-free particles C

A preferred embodiment of the polarized particles that can be used in the electrorheological fluid of the present invention is a particle composed of two or more kinds of particles having different average particle diameters represented by A to C, and having two or more kinds of different average particle diameters. Examples of the above are those in which the concentrations of the electrolytes contained in the particles differ from each other due to the difference in the average particle size.
Further, as a preferred embodiment of the polarized particles that can be used in the electrorheological fluid of the present invention, the polarized particles include the particles having the average particle diameter indicated by C, and are contained in the particles having the average particle diameter indicated by C. Examples thereof include those in which the concentration of the electrolyte is higher than that of other particles having an average particle size.

Specific polarized particles that can be used in the present invention include particles B (II) having a low electrolyte concentration of 70 to 90% by mass and particles C (VI) having a high electrolyte concentration based on the total mass of the polarized particles. Is preferably contained in an amount of 10 to 20% by mass, and particles B (II) having a low concentration of electrolyte are preferably contained in an amount of 85 to 95% by mass and particles C (VI) having a high concentration of electrolyte are preferably contained in an amount of 5 to 15% by mass. ..

The amount of polarized particles contained in the electrorheological fluid of the present invention is in the range of 30 to 60% by mass, preferably in the range of 40 to 60% by mass, based on the total mass of the electrically insulating medium.

An emulsifier may be further added to the electrorheological fluid of the present invention.
Emulsifiers that can be added to the electrorheological fluids of the present invention include surfactants that are soluble in electrically insulating media and are derived from, for example, amides, imidazolines, oxazolines, alcohols, glycols or sorbitols. Polymers soluble in electrically insulating media can also be used. Suitable polymers are, for example, 0.1 to 10 wt% of N and / or OH and 25 to 83 wt% of C ₄ -C ₂₄ - containing alkyl group, and a molecular weight of weight average in the range from 5000 1000000 To have. The N and OH-containing compounds in these polymers are, for example, amino, amide, imide, nitrilo, 5- and / or 6-membered N-containing heterocycles or alcohols, and C _{4 of} acrylic acid or methacrylic acid. It can contain a −C ₂₄ -alkyl ester. Examples of the N and OH-containing compounds described above include N, N-dimethylaminoethyl methacrylate, tert. -Butylacrylamide, imide maleate, acrylonitrile, N-vinylpyrrolidone, vinylpyridine and 2-hydroxyethyl methacrylate. Overall, the polymers have the advantage that the systems prepared using them are more stable with respect to sedimentation dynamics compared to low molecular weight surfactants. Modified silicone oils such as amino-modified silicone or fluorine-modified silicone can also be used.

Further, a lubricant may be added to the electrorheological fluid of the present invention.
Examples of the lubricant include polydimethylsiloxane, polytrifluoropropylmethylsiloxane, and oil-based lubricants such as a copolymer of dimethylsiloxane and trifluoropropylmethylsiloxane.

As the electrorheological fluid of the present invention, a mixture of two or more of the above-mentioned electrorheological fluids can also be used.

The method for preparing the electrorheological fluid of the present invention will be described below.
The electrorheological fluid of the present invention is prepared, for example, by mixing a plurality of types of fluids containing polarized particles having a specific electrolyte concentration and a specific average particle size.
Specifically, two or more kinds of nine kinds of fluids including each of the nine kinds of polarized particles represented by the above (I) to (IX) (however, the polarized particles contained in at least two kinds of fluids have the concentration of electrolyte. ) Can be prepared by mixing in a specific ratio.
The preparation of each fluid when polyurethane particles are used as the polarization particles can be achieved by performing an operation according to the manufacturing flowchart shown in FIG.
Each process described in the manufacturing flowchart in FIG. 1 will be described below.

1. 1. Initial weighing + dissolution This step is a step of separately preparing a solution containing an electrically insulating medium, an emulsifier, a lubricant, etc. (also referred to as solution 1) and a solution containing a polyol and an electrolyte (also referred to as solution 2). is there.
The prepared solution 1 and solution 2 are individually stored at room temperature (20 ± 10 ° C.) and mixed in the next step (initial emulsification).
The preparation of each solution is described below.

(1) Preparation of solution (solution 1) containing electrically insulating medium, emulsifier, lubricant, etc. Weigh each of the electrically insulating medium, emulsifier, lubricant, etc., add to a compounding bottle or a glass beaker of an appropriate amount, and magnetize sooter. Each material is mixed and dissolved at room temperature using a glass and a magnet stirrer, or a stirring blade that is optimal for a three-one motor (according to the blending amount).
Here, the stirring speed (rotation speed) is usually equivalent to 100 rpm / s or more, the stirring time is 2 hours or more, and the temperature is normal temperature (20 ± 10 ° C.). After the specified stirring is completed, visually check the appearance that there is no "undissolved substance or precipitate", and if "undissolved or precipitate" is confirmed, additional stirring for 2 hours ( Stirring conditions are the same as above) as one set, and stirring is continued until "undissolved substances and precipitates" disappear (visual confirmation becomes impossible).

(2) Preparation of a solution (solution 2) containing a polyol and an electrolyte The electrolyte concentration of the polarized particles is determined by the amount of the electrolyte used here. That is, when the amount of the electrolyte used is increased, particles having a high concentration of electrolyte are formed, and by decreasing the amount of electrolyte, particles having a low concentration of electrolyte are formed, and no electrolyte is added. Particles containing no electrolyte will be formed.
Weigh the polyol and electrolyte, add them to a blending bottle or a glass beaker of an appropriate size, and use a magnetic stirrer and a magnetic stir bar, or a stirring blade that is optimal for the three-one motor (depending on the blending amount) to prepare each material. Mix and dissolve by heating and stirring.
Here, the stirring speed (rotation speed) is equivalent to 100 rpm / s or more, the stirring time is 8 hours or more, and the heating temperature is 50 to 80 ° C., preferably 60 to 70 ° C., for example, 65 ° C. Is. After the specified stirring is completed, visually check that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, at the same temperature as above. With 2 hours of additional stirring (stirring conditions are the same as above) as one set, stirring is continued until "undissolved substances and precipitates" disappear (visual confirmation becomes impossible).

When two or more kinds of electrolytes are used in combination as the electrolyte, it is preferable to dissolve them step by step. For example, it is preferable to add one kind of electrolyte and completely dissolve it, and then add the next one kind of electrolyte to completely dissolve it.
When forming particles having a low concentration of electrolyte, the amount of electrolyte to be added is in the range where the final amount of metal ions contained in the particles is 0.01 ppm or more and less than 750.00 ppm, preferably 10 ppm or more and 750.00 ppm. When forming particles having a low electrolyte concentration, the final amount of metal ions contained in the particles is in the range of 750.00 ppm or more and 1500.00 ppm or less, preferably 800.00 ppm. The amount is 1500.00 ppm or less.
For example, when lithium chloride and zinc chloride are used in combination as the electrolyte, the total amount of addition is such that the total amount of lithium ions and zinc ions in the low-concentration particles is in the range of 0.01 ppm or more and less than 750.00 ppm. Preferably, it is 10 ppm or more and 750.00.
The amount is in the range of less than ppm, and the total amount of lithium ions and zinc ions in the high-concentration particles is in the range of 750.00 ppm or more and 1500.00 ppm or less, preferably 800.00 ppm or more and 1500.00 ppm or less. It is a range amount.

A catalyst can also be added to solution 2 after the electrolyte is completely dissolved.
Examples of the catalyst include amine-based catalysts, and specifically, triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0]. Examples thereof include undecene, N, N, N', N'-tetramethyl-1,3-butanediamine, N-ethylmorpholine and the like.
When the catalyst is added, the stirring speed (rotation speed) at the time of adding the catalyst is equivalent to 100 rpm / s or more, the stirring time is 2 hours or more, and the heating temperature is 50 to 80 ° C., preferably 60. Or 70 ° C, for example 65 ° C. After the specified stirring is completed, visually check that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, at the same temperature as above. With 1 hour of additional stirring (stirring conditions are the same as above) as one set, stirring is continued until "undissolved substances and precipitates" disappear (visual confirmation becomes impossible).

2. 2. Initial emulsification (shear / dispersion I)
This is a step of mixing and emulsifying the solution 1 and the solution 2 prepared above while being dispersed (sheared) by a disperser, depending on the rotation speed (speed) of the shear blades of the disperser and the number of repetitions of the operation in the step. , The average particle size of the particles formed in a later step will be determined.
The specific operation is as follows.

(A) Solution 1 and solution 2 are simultaneously supplied to the supply port of the disperser at a constant amount (ratio) / constant speed (flow velocity) via diaphragm pumps (non-pulsating metering pumps) of different systems.
(B) At that time, when particles A (small particles) and particles B (medium particles) are formed in a later step, 26000 rpm / s is used as the rotation speed (speed) of the shear blade of the disperser, and later. When particles C (large particles) are formed in the process, 5000 to 10000 rpm / s is used as the rotation speed (speed) of the shear blades of the disperser.
(C) The solution emulsified (dispersed and mixed) by the disperser is discharged (press-fed) and stored in the stirring tank.
(D) In the stirring tank, a three-one motor is used, for example, two Dispa TYPE blades are used, and stirring is performed at a rotation speed of 300 to 500 rpm / s, which is optimal depending on the amount of solution supplied into the tank. Make fine adjustments to the number of revolutions.
(E) When the initial emulsification of the entire amounts of the solution 1 and the solution 2 is completed according to the above (a) to (c), the emulsified solution is supplied to the disperser again from the lower bottom of the stirring tank via the diaphragm pump and emulsified. Perform (dispersion mixing) processing.

The above operations (a) to (e) are repeated, and the number of repetitions is 20 or more when particles A (small particles) are formed in a later step, and particles B (in the later steps). When forming particles (medium particles), it is 10 to 19 times, for example, 14 times, and when forming particles C (large particles) in a later step, it is once.

3. 3. Pre-curing (hardener addition I + dispersion II)
The purpose of this step is to cure the uncured emulsion particles produced in the dispersion step in the initial emulsification step, and 15% of the total amount of the curing agent (isocyanate) used to form the polarized particles is used. use.
The purpose of the dispersion treatment carried out in this step is to "add a light dispersion that breaks the bias of the addition of the curing agent and the bond (adhesion) between the particles", and the size of the average particle size of the polarized particles. Does not have a direct impact on.
The specific operation is as follows.

The above 2. is being stored in a stirring state in a stirring tank. To the emulsion prepared by the initial emulsification (shear / dispersion I), a curing agent (isocyanate) in an amount of 15% of the total addition amount is added dropwise using a tube pump while continuing the same stirring.
Since the liquid temperature rises due to the "heat of reaction (isocyanate reaction)" at the time of addition, the liquid temperature is adjusted within a range not exceeding 50 ° C. with a cooling chiller provided in the stirring tank.
After the addition of the specified amount of hardener is completed, it is supplied from the lower bottom of the stirring tank to the disperser used in the initial emulsification via the diaphragm pump to perform the dispersion treatment.
However, the supply rate to the disperser in the above dispersion treatment is 50% of the rate at the time of initial emulsification, and the dispersion condition is when particles A (small particles) and particles B (medium particles) are formed in a later step. When 26000 rpm / s is used as the rotation speed (speed) of the shear blades of the disperser and particles C (large particles) are formed in a later step, 5000 to 5000 as the rotation speed (speed) of the shear blades of the disperser. At 10000 rpm / s, the number of repetitions in this dispersion process is usually one.

4. Main curing (hardener addition II + stirring)
In this step, the above 3. The remaining amount, or total amount, of the curing agent (isocyanate) used to form the polarized particles for the purpose of further curing the semi-cured emulsion particles formed by pre-curing (hardener addition I + dispersion II). Use 85% of the amount.
The specific operation is as follows.

Above 3. After the pre-curing (hardener addition I + dispersion II) operation (including additional dispersion treatment) is completed, the emulsion of semi-cured polarized particles (polyurethane particles) stored in a stirring state in a stirring tank is stirred. While increasing the force and stirring at a rotation speed of 500 to 700 rpm / s, the remaining amount of the curing agent (isocyanate), that is, 85% of the total amount is added dropwise using a tube pump, and at the time of addition, "reaction heat (reaction heat (reaction heat) Since the liquid temperature rises due to "isocyanate reaction)", the liquid temperature is adjusted (cooled) within a range not exceeding 50 ° C. with a cooling device.

5. Immobilization (heating + stirring)
4. above. After the final addition of the curing agent in the main curing (hardener addition II + stirring) is completed, a heating heat treatment is performed in this step in order to perform "complete curing".
The specific operation is as follows.

4. above. The emulsion of the cured polarized particles (polyurethane particles) prepared by the main curing (hardener addition II + stirring) is transferred from the stirring tank to the compounding bottle used in the initial weighing, and heated using a stirrer with a heating function. Mix with warm stirring.
Here, the stirring speed (rotation speed) is equivalent to 100 rpm / s or more, the stirring time is 8 hours or more, and the heating temperature is 50 to 80 ° C., preferably 60 to 70 ° C., for example, 65 ° C. Is. After the completion of the heating and stirring, the heat retention function is stopped, and the stirring is continued while naturally cooling until the liquid temperature reaches room temperature (room temperature (20-30 ° C.)) at the same rotation speed.

6. Filtration (SUS mesh # 125)
5. The fluid for which the immobilization (heating + stirring) operation has been completed is filtered. Here, in order to prevent scattering to the inner wall of the container and remove dry debris and impurities, filtration treatment is performed in two steps.
That is, the fluid is filtered (first time) using a filtration mesh of (opening) 180 μm and (wire diameter) 125 μm, and then using a filtering mesh of (opening) 180 μm and (wire diameter) 125 μm. The fluid is filtered (second time).

A specific ratio of two or more kinds of fluids containing polarized particles having a specific electrolyte concentration and a specific average particle size prepared above (however, the polarized particles contained in at least two kinds of fluids have different electrolyte concentrations). The electroviscous fluid of the present invention can be produced by mixing with.
As an example of mixing two or more kinds of preferable fluids, the polarized particles in the mixed fluid have a low electrolyte concentration of 70 to 90% by mass and the electrolyte concentration based on the total mass of the polarized particles. It is preferable that the particles C (VI) having a high concentration of 10 to 20% by mass are mixed, and the particles B (II) having a low concentration of electrolyte are 85 to 95% by mass and the particles C (VI) having a high concentration of electrolyte are 85 to 95% by mass. A mixing ratio of 5 to 15% by mass is also preferable.

Next, examples will be given to explain the present invention in more detail, but the present invention is not limited thereto.

Preparation Example 1: Preparation of fluid 1 (fluid containing particles B (II) having a low concentration of electrolyte) 1. Initial weighing + dissolution (1) Preparation of solution containing electrically insulating medium, emulsifier, lubricant, etc. In a compounding bottle,
-Silicone oil (KF96-5cs: manufactured by Shin-Etsu Chemical Co., Ltd.) 489.0 g
-Emulsifier (OF7747: manufactured by Momentive Performance Materials GK) 8.8 g, and-Lubricant (GPW2233: manufactured by Momentive Performance Materials GK) 16.1 g
Was weighed and added, and the mixture was stirred at a stirring speed (rotation speed) of 100 rpm / s or more and at room temperature (20 ± 10 ° C.) for 2 hours.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, perform additional stirring for 2 hours (stirring conditions are the same as above). As one set, stirring was continuously carried out until "undissolved substances and precipitates" disappeared (visual confirmation became impossible), and a solution containing an electrically insulating medium, an emulsifier, a lubricant and the like was prepared.

(2) Preparation of solution containing polyol and electrolyte In another compounding bottle,
400.0 g of polyol (polypoly 3165: manufactured by Perstoop) and 0.03 g of LiCl (lithium chloride: manufactured by Wako Pure Chemical Industries, Ltd.)
Was weighed and added, and the mixture was stirred at a stirring speed (rotation speed) of 100 rpm / s or more and a heating set temperature of 65 ° C. for 8 hours.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, additional stirring for 2 hours at the same temperature as above (stirring conditions). The same as above) was used as one set, and stirring was continued until "undissolved substances and precipitates" disappeared (visual confirmation became impossible).
In addition to the above solution
・ ZnCl ₂ (Zinc chloride: manufactured by Wako Pure Chemical Industries, Ltd.) 0.68 g
Was weighed and added, and the mixture was stirred for 2 hours at a stirring speed (rotation speed) of 100 rpm / s or more and a heating set temperature of 65 ° C.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, additional stirring for 2 hours at the same temperature as above (stirring conditions). The same as above) was used as one set, and stirring was continued until "undissolved substances and precipitates" disappeared (visual confirmation became impossible).
In addition to the above solution
DABCO (1,4-diazabicyclo [2.2.2] octane: manufactured by Tokyo Chemical Industry Co., Ltd.) 1.11 g
Was weighed and added, and the mixture was stirred for 2 hours at a stirring speed (rotation speed) of 100 rpm / s or more and a heating set temperature of 65 ° C.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates"
If is confirmed, continue stirring at the same temperature as above for 1 hour with additional stirring (stirring conditions are the same as above) until there are no "undissolved substances or precipitates" (visual confirmation becomes impossible). This was carried out to prepare a solution containing the polyol and electrolyte.
The prepared solution containing the electrically insulating medium, emulsifier, lubricant and the like, and the solution containing the polyol and the electrolyte were individually stored at room temperature (20 ± 10 ° C.) and mixed in the next step (initial emulsification).

2. 2. Initial emulsification (shear / dispersion I)
(A) A constant amount (ratio) / constant speed (flow velocity) of a solution containing an electrically insulating medium, an emulsifier, a lubricant, etc., and a solution containing a polyol and an electrolyte via separate diaphragm pumps (pulsation-free metering pumps). At the same time, the solution was supplied to the supply port of the disperser (manufactured by IKA Japan: IKA-5L-magic-Lab).
(B) At that time, the rotation speed (speed) of the shear blade of the disperser was set to 26000 rpm / s. (C) The solution emulsified (dispersed and mixed) by the disperser was discharged (pressure-fed) to a stirring tank (homemade SUS tank: 5 L) and stored.
(D) In the stirring tank, a three-one motor (Fine Co., Ltd .: FBL-600) was used, two dispa TYPE blades were used, and stirring was performed at a rotation speed of 300 to 500 rpm / s, but the mixture was supplied into the tank. The rotation speed was finely adjusted according to the amount of the solution.
(E) When the initial emulsification of the entire amount of the solution containing the electrically insulating medium, the emulsifier, the lubricant and the like and the solution containing the polyol and the electrolyte is completed according to the above (a) to (c), from the lower bottom of the stirring tank via the diaphragm pump. Then, the emulsified solution was supplied to the disperser again, emulsification (dispersion mixing) treatment was performed, and the above operations (a) to (e) were repeated 14 times.

3. 3. Pre-curing (hardener addition I + dispersion II)
2. Stored in a stirring state in a stirring tank. To the emulsion prepared in the initial emulsification (shearing / dispersion I) step, 14.20 g of the curing agent TDI (Torrange isocyanate: manufactured by Tokyo Chemical Industry Co., Ltd./T-80) was added to the tube pump (ASONE) while continuing stirring. (Manufactured by SMP-21AS) was added dropwise (addition rate: volume 3).
Since the liquid temperature rises due to the "heat of reaction (isocyanate reaction)" when the curing agent TDI is added, the liquid temperature was adjusted within a range not exceeding 50 ° C. with a cooling chiller provided in the stirring tank.
After the addition of the specified amount of the curing agent was completed, the mixture was supplied from the lower bottom of the stirring tank to the disperser used in the initial emulsification via a diaphragm pump at a rate of 50% of that in the initial emulsification, and the dispersion treatment was performed.
The dispersion condition at this time was that the rotation speed (speed) of the shear blades of the disperser was 26000 rpm / s, and the same operations as in (a) to (e) above were performed once.

4. Main curing (hardener addition II + stirring)
Above 3. After the pre-curing (hardener addition I + dispersion II) process is completed, the stirring power is increased in the emulsion of the semi-cured polyurethane particles that are being stored in the same stirring tank in the stirring state, and the rotation speed is 500 to 700 rpm / While stirring at s, 80.40 g of the curing agent TDI (Torrange isocyanate: manufactured by Tokyo Kasei Kogyo Co., Ltd./T-80) was added dropwise using a tube pump (manufactured by ASONE: SMP-21AS) (addition). Speed: volume 3-10).
Since the liquid temperature rises due to the "heat of reaction (isocyanate reaction)" when the curing agent TDI is added, the liquid temperature was adjusted within a range not exceeding 50 ° C. with a cooling chiller provided in the stirring tank.

5. Immobilization (heating + stirring)
Above 4. After the main curing (hardener addition II + stirring) process is completed, the cured polyurethane particle emulsion is transferred from the stirring tank to the compounding bottle used in the initial weighing, with a stirrer + heating function (normal temperature to 250 ° C range). Liquid temperature: 65 ° C., stirring speed (rotation speed): equivalent to 100 rpm / s or more, stirring time: 8 using a magnetic stirrer (hot magnetic stirrer)
It was heated and stirred for more than an hour.
After the completion of the heating and stirring, the heat retention function was stopped, and the stirring was continued while naturally cooling the liquid at room temperature: room temperature (20-30 ° C.) at the same rotation speed.

6. Filtration (SUS mesh # 125)
5. Above. After the immobilization (heating + stirring) process is completed, the prepared fluid is applied to the prepared fluid using a filtration mesh (manufactured by Tokyo Screen Co., Ltd .: TESTING SIEVE) with (opening of eyes) 180 μm and (wire diameter) 125 μm. , The fluid is filtered (first time), and then the fluid is filtered using a filtration mesh (manufactured by Tokyo Screen Co., Ltd .: TESTING SIEVE) with (opening of eyes) 180 μm and (wire diameter) 125 μm (second time). Then, a fluid 1 (a fluid containing particles B (II) having a low concentration of electrolyte) was obtained.

The average particle size of the particles in the fluid 1 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 3.7 μm. Further, when the amount of ions of the particles in the fluid 1 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 30 ppm and the amount of zinc ions was 680 ppm (total 710 ppm).

Preparation Example 2: Preparation of fluid 2 (fluid containing particles A (I) having a low concentration of electrolyte) 2. The same operation as in Preparation Example 1 was performed except that the operations (a) to (e) in the initial emulsification (shear / dispersion I) were repeated 20 times or more, and the fluid 2 (particle A having a low electrolyte concentration) was subjected to the same operation. A fluid containing (I)) was obtained.

The average particle size of the particles in the fluid 2 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 2.4 μm. Further, when the amount of ions of the particles in the fluid 2 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 30 ppm and the amount of zinc ions was 680 ppm (total 710 ppm).

Preparation Example 3: Preparation of fluid 3 (fluid containing particles C (III) having a low concentration of electrolyte) 2. The rotation speed (speed) of the shear blade of the disperser in (b) of the initial emulsification (shearing / dispersion I) is set to 5000 to 10000 rpm / s, and the operations of (a) to (e) are repeated once, and 3 .. The fluid was operated in the same manner as in Preparation Example 1 except that the dispersion conditions (rotation speed (speed) of the shear blades of the disperser) in the pre-curing (hardener addition I + dispersion II) were set to 5000 to 10000 rpm / s. 3 (fluid containing particles C (III) having a low concentration of electrolyte) was obtained.

The average particle size of the particles in the fluid 3 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 6.5 μm. Further, when the amount of ions of the particles in the fluid 3 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 30 ppm and the amount of zinc ions was 680 ppm (total 710 ppm).

Preparation Example 4: Preparation of fluid 4 (fluid containing particles B (V) having a high concentration of electrolyte) 1. Initial weighing + dissolution (1) Preparation of solution containing electrically insulating medium, emulsifier, lubricant, etc. In a compounding bottle,
-Silicone oil (KF96-5cs: manufactured by Shin-Etsu Chemical Co., Ltd.) 488.73 g
-Emulsifier (OF7747: manufactured by Momentive Performance Materials GK) 8.8 g, and-Lubricant (GPW2233: manufactured by Momentive Performance Materials GK) 1
6.1g
Was weighed and added, and the mixture was stirred at a stirring speed (rotation speed) of 100 rpm / s or more and at room temperature (20 ± 10 ° C.) for 2 hours.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, perform additional stirring for 2 hours (stirring conditions are the same as above). As one set, stirring was continuously carried out until "undissolved substances and precipitates" disappeared (visual confirmation became impossible), and a solution containing an electrically insulating medium, an emulsifier, a lubricant and the like was prepared.

(2) Preparation of solution containing polyol and electrolyte In another compounding bottle,
400.0 g of polyol (polypoly 3165: manufactured by Perstoop) and 0.30 g of LiCl (lithium chloride: manufactured by Wako Pure Chemical Industries, Ltd.)
Was weighed and added, and the mixture was stirred at a stirring speed (rotation speed) of 100 rpm / s or more and a heating set temperature of 65 ° C. for 8 hours.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, additional stirring for 2 hours at the same temperature as above (stirring conditions). The same as above) was used as one set, and stirring was continued until "undissolved substances and precipitates" disappeared (visual confirmation became impossible).
In addition to the above solution
・ ZnCl ₂ (Zinc chloride: manufactured by Wako Pure Chemical Industries, Ltd.) 0.68 g
Was weighed and added, and the mixture was stirred for 2 hours at a stirring speed (rotation speed) of 100 rpm / s or more and a heating set temperature of 65 ° C.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, additional stirring for 2 hours at the same temperature as above (stirring conditions). The same as above) was used as one set, and stirring was continued until "undissolved substances and precipitates" disappeared (visual confirmation became impossible).
In addition to the above solution
DABCO (1,4-diazabicyclo [2.2.2] octane: manufactured by Tokyo Chemical Industry Co., Ltd.) 1.11 g
Was weighed and added, and the mixture was stirred for 2 hours at a stirring speed (rotation speed) of 100 rpm / s or more and a heating set temperature of 65 ° C.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, additional stirring for 1 hour at the same temperature as above (stirring conditions). Was the same as above) as one set, and stirring was continued until "undissolved substances and precipitates" disappeared (visual confirmation became impossible) to prepare a solution containing a polyol and an electrolyte.
The prepared solution containing the electrically insulating medium, emulsifier, lubricant and the like, and the solution containing the polyol and the electrolyte were individually stored at room temperature (20 ± 10 ° C.) and mixed in the next step (initial emulsification).

2. 2. Initial emulsification (shear / dispersion I)
(A) A constant amount (ratio) / constant speed (flow velocity) of a solution containing an electrically insulating medium, an emulsifier, a lubricant, etc., and a solution containing a polyol and an electrolyte via separate diaphragm pumps (pulsation-free metering pumps). At the same time, the solution was supplied to the supply port of the disperser (manufactured by IKA Japan: IKA-5L-magic-Lab).
(B) At that time, the rotation speed (speed) of the shear blade of the disperser was set to 26000 rpm / s. (C) The solution emulsified (dispersed and mixed) by the disperser was discharged (pressure-fed) to a stirring tank (homemade SUS tank: 5 L) and stored.
(D) In the stirring tank, a three-one motor (Fine Co., Ltd .: FBL-600) was used, two dispa TYPE blades were used, and stirring was performed at a rotation speed of 300 to 500 rpm / s, but the mixture was supplied into the tank. The rotation speed was finely adjusted according to the amount of the solution.
(E) When the initial emulsification of the entire amount of the solution containing the electrically insulating medium, the emulsifier, the lubricant and the like and the solution containing the polyol and the electrolyte is completed according to the above (a) to (c), from the lower bottom of the stirring tank via the diaphragm pump. Then, the emulsified solution was supplied to the disperser again, emulsification (dispersion mixing) treatment was performed, and the above operations (a) to (e) were repeated 14 times.

3. 3. Pre-curing (hardener addition I + dispersion II)
2. Stored in a stirring state in a stirring tank. To the emulsion prepared in the initial emulsification (shearing / dispersion I) step, 14.20 g of the curing agent TDI (Torrange isocyanate: manufactured by Tokyo Chemical Industry Co., Ltd./T-80) was added to the tube pump (ASONE) while continuing stirring. (Manufactured by SMP-21AS) was added dropwise (addition rate: volume 3).
Since the liquid temperature rises due to the "heat of reaction (isocyanate reaction)" when the curing agent TDI is added, the liquid temperature was adjusted within a range not exceeding 50 ° C. with a cooling chiller provided in the stirring tank.
After the addition of the specified amount of the curing agent was completed, the mixture was supplied from the lower bottom of the stirring tank to the disperser used in the initial emulsification via a diaphragm pump at a rate of 50% of that in the initial emulsification, and the dispersion treatment was performed.
The dispersion condition at this time was that the rotation speed (speed) of the shear blades of the disperser was 26000 rpm / s, and the same operations as in (a) to (e) above were performed once.

4. Main curing (hardener addition II + stirring)
Above 3. After the pre-curing (hardener addition I + dispersion II) process is completed, the stirring power is increased in the emulsion of the semi-cured polyurethane particles that are being stored in the same stirring tank in the stirring state, and the rotation speed is 500 to 700 rpm / While stirring at s, 80.40 g of the curing agent TDI (Torrange isocyanate: manufactured by Tokyo Kasei Kogyo Co., Ltd./T-80) was added dropwise using a tube pump (manufactured by ASONE: SMP-21AS) (addition). Speed: volume 3-10).
Since the liquid temperature rises due to the "heat of reaction (isocyanate reaction)" when the curing agent TDI is added, the liquid temperature was adjusted within a range not exceeding 50 ° C. with a cooling chiller provided in the stirring tank.

5. Immobilization (heating + stirring)
Above 4. After the main curing (hardener addition II + stirring) process is completed, the cured polyurethane particle emulsion is transferred from the stirring tank to the compounding bottle used in the initial weighing, with a stirrer + heating function (normal temperature to 250 ° C range). Using a magnetic stirrer (hot magnetic stirrer), the liquid temperature was 65 ° C., the stirring speed (rotation speed) was equivalent to 100 rpm / s or more, and the stirring time was 8 hours or more.
After the completion of the heating and stirring, the heat retention function was stopped, and the stirring was continued while naturally cooling the liquid at room temperature: room temperature (20-30 ° C.) at the same rotation speed.

6. Filtration (SUS mesh # 125)
5. Above. After the immobilization (heating + stirring) process is completed, the prepared fluid is applied to the prepared fluid using a filtration mesh (manufactured by Tokyo Screen Co., Ltd .: TESTING SIEVE) with (opening of eyes) 180 μm and (wire diameter) 125 μm. , The fluid is filtered (first time), and then the fluid is filtered using a filtration mesh (manufactured by Tokyo Screen Co., Ltd .: TESTING SIEVE) with (opening of eyes) 180 μm and (wire diameter) 125 μm (second time). Then, a fluid 4 (a fluid containing particles B (V) having a high concentration of electrolyte) was obtained.

The average particle size of the particles in the fluid 4 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 3.7 μm. Further, when the amount of ions of the particles in the fluid 4 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 300 ppm and the amount of zinc ions was 680 ppm (total 980 ppm).

Preparation Example 5: Preparation of fluid 5 (fluid containing particles A (IV) having a high concentration of electrolyte) 2. The same operation as in Preparation Example 4 was performed except that the operations (a) to (e) in the initial emulsification (shear / dispersion I) were repeated 20 times or more, and the fluid 5 (particle A having a high concentration of electrolyte) was performed. (Fluid containing (IV)) was obtained.

The average particle size of the particles in the fluid 5 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 2.4 μm. Further, when the amount of ions of the particles in the fluid 5 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 300 ppm and the amount of zinc ions was 680 ppm (total 980 ppm).

Preparation Example 6: Preparation of fluid 6 (fluid containing particles C (VI) having a high concentration of electrolyte) 2. The rotation speed (speed) of the shear blade of the disperser in (b) of the initial emulsification (shearing / dispersion I) is set to 5000 to 10000 rpm / s, and the operations of (a) to (e) are repeated once, and 3 .. The fluid was operated in the same manner as in Preparation Example 4 except that the dispersion conditions (rotation speed (speed) of the shear blades of the disperser) in the pre-curing (hardener addition I + dispersion II) were set to 5000 to 10000 rpm / s. 6 (fluid containing particles C (VI) having a high concentration of electrolyte) was obtained.

The average particle size of the particles in the fluid 6 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 6.5 μm. Further, when the amount of ions of the particles in the fluid 6 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 300 ppm and the amount of zinc ions was 680 ppm (total 980 ppm).

Preparation Example 7: Preparation of fluid 7 (fluid containing particles B (VIII) containing no electrolyte) 1. Initial weighing + dissolution (1) Preparation of solution containing electrically insulating medium, emulsifier, lubricant, etc. In a compounding bottle,
-Silicone oil (KF96-5cs: manufactured by Shin-Etsu Chemical Co., Ltd.) 489.71 g
-Emulsifier (OF7747: manufactured by Momentive Performance Materials GK) 8.8 g, and-Lubricant (GPW2233: manufactured by Momentive Performance Materials GK) 16.1 g
Was weighed and added, and the mixture was stirred at a stirring speed (rotation speed) of 100 rpm / s or more and at room temperature (20 ± 10 ° C.) for 2 hours.
Visually check the appearance that there are no "undissolved substances or precipitates", and if "undissolved substances or precipitates" are confirmed, perform additional stirring for 2 hours (stirring conditions are the same as above). As one set, stirring was continuously carried out until "undissolved substances and precipitates" disappeared (visual confirmation became impossible), and a solution containing an electrically insulating medium, an emulsifier, a lubricant and the like was prepared.

(2) Preparation of solution containing polyol In another compounding bottle,
400.0 g of polyol (polyol 3165: manufactured by Perstoop) and 1.11 g of DABCO (1,4-diazabicyclo [2.2.2] octane: manufactured by Tokyo Chemical Industry Co., Ltd.)
Was weighed and added, and the mixture was stirred for 2 hours at a stirring speed (rotation speed) of 100 rpm / s or more and a heating set temperature of 65 ° C.
Visually check the appearance that there is no "undissolved substance or precipitate", and if "undissolved substance or precipitate" is confirmed, additional stirring for 1 hour at the same temperature as above (stirring condition). Was the same as above) as one set, and stirring was continued until "undissolved substances and precipitates" disappeared (visual confirmation became impossible) to prepare a solution containing a polyol and an electrolyte.
The prepared solution containing the electrically insulating medium, emulsifier, lubricant and the like, and the solution containing the polyol and the electrolyte were individually stored at room temperature (20 ± 10 ° C.) and mixed in the next step (initial emulsification).

2. 2. Initial emulsification (shear / dispersion I)
(A) A constant amount (ratio) / constant speed (flow velocity) of a solution containing an electrically insulating medium, an emulsifier, a lubricant, etc., and a solution containing a polyol and an electrolyte via separate diaphragm pumps (pulsation-free metering pumps). At the same time, the solution was supplied to the supply port of the disperser (manufactured by IKA Japan: IKA-5L-magic-Lab).
(B) At that time, the rotation speed (speed) of the shear blade of the disperser was set to 26000 rpm / s. (C) The solution emulsified (dispersed and mixed) by the disperser was discharged (pressure-fed) to a stirring tank (homemade SUS tank: 5 L) and stored.
(D) In the stirring tank, a three-one motor (Fine Co., Ltd .: FBL-600) was used, two dispa TYPE blades were used, and stirring was performed at a rotation speed of 300 to 500 rpm / s, but the mixture was supplied into the tank. The rotation speed was finely adjusted according to the amount of the solution.
(E) When the initial emulsification of the entire amount of the solution containing the electrically insulating medium, the emulsifier, the lubricant and the like and the solution containing the polyol and the electrolyte is completed according to the above (a) to (c), from the lower bottom of the stirring tank via the diaphragm pump. Then, the emulsified solution was supplied to the disperser again, emulsification (dispersion mixing) treatment was performed, and the above operations (a) to (e) were repeated 14 times.

3. 3. Pre-curing (hardener addition I + dispersion II)
2. Stored in a stirring state in a stirring tank. To the emulsion prepared in the initial emulsification (shearing / dispersion I) step, 14.20 g of the curing agent TDI (Torrange isocyanate: manufactured by Tokyo Chemical Industry Co., Ltd./T-80) was added to the tube pump (ASONE) while continuing stirring. (Manufactured by SMP-21AS) was added dropwise (addition rate: volume 3).
Since the liquid temperature rises due to the "heat of reaction (isocyanate reaction)" when the curing agent TDI is added, the liquid temperature was adjusted within a range not exceeding 50 ° C. with a cooling chiller provided in the stirring tank.
After the addition of the specified amount of the curing agent was completed, the mixture was supplied from the lower bottom of the stirring tank to the disperser used in the initial emulsification via a diaphragm pump at a rate of 50% of that in the initial emulsification, and the dispersion treatment was performed.
The dispersion condition at this time was that the rotation speed (speed) of the shear blades of the disperser was 26000 rpm / s, and the same operations as in (a) to (e) above were performed once.

4. Main curing (hardener addition II + stirring)
Above 3. After the pre-curing (hardener addition I + dispersion II) process is completed, the stirring power is increased in the emulsion of the semi-cured polyurethane particles that are being stored in the same stirring tank in the stirring state, and the rotation speed is 500 to 700 rpm / While stirring at s, 80.40 g of the curing agent TDI (Torrange isocyanate: manufactured by Tokyo Kasei Kogyo Co., Ltd./T-80) was added dropwise using a tube pump (manufactured by ASONE: SMP-21AS) (addition). Speed: volume 3-10).
Since the liquid temperature rises due to the "heat of reaction (isocyanate reaction)" when the curing agent TDI is added, the liquid temperature was adjusted within a range not exceeding 50 ° C. with a cooling chiller provided in the stirring tank.

5. Immobilization (heating + stirring)
Above 4. After the main curing (hardener addition II + stirring) process is completed, the cured polyurethane particle emulsion is transferred from the stirring tank to the compounding bottle used in the initial weighing, with a stirrer + heating function (normal temperature to 250 ° C range). Using a magnetic stirrer (hot magnetic stirrer), the liquid temperature was 65 ° C., the stirring speed (rotation speed) was equivalent to 100 rpm / s or more, and the stirring time was 8 hours or more.
After the heating and stirring are completed, the heat retention function is stopped and the liquid temperature remains at room temperature: room temperature (20-3) at the same rotation speed.
Stirring was continued while naturally cooling until the temperature reached 0 ° C.).

6. Filtration (SUS mesh # 125)
5. Above. After the immobilization (heating + stirring) process is completed, the prepared fluid is applied to the prepared fluid using a filtration mesh (manufactured by Tokyo Screen Co., Ltd .: TESTING SIEVE) with (opening of eyes) 180 μm and (wire diameter) 125 μm. , The fluid is filtered (first time), and then the fluid is filtered using a filtration mesh (manufactured by Tokyo Screen Co., Ltd .: TESTING SIEVE) with (opening of eyes) 180 μm and (wire diameter) 125 μm (second time). A fluid 7 (a fluid containing particles B (VIII) containing no electrolyte) was obtained.

The average particle size of the particles in the fluid 7 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 3.7 μm. Further, when the amount of ions of the particles in the fluid 7 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 0 ppm and the amount of zinc ions was 0 ppm (total 0 ppm).

Preparation Example 8: Preparation of fluid 8 (fluid containing particles A (VII) containing no electrolyte) 2. The same operation as in Preparation Example 7 was performed except that the operations (a) to (e) in the initial emulsification (shear / dispersion I) were repeated 20 times or more, and the fluid 8 (electrolyte-free particles A (electrolyte-free particles A) was performed. A fluid containing VII) was obtained.

The average particle size of the particles in the fluid 8 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 2.4 μm. Further, when the amount of ions of the particles in the fluid 8 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 0 ppm and the amount of zinc ions was 0 ppm (total 0 ppm).

Preparation Example 9: Preparation of fluid 9 (fluid containing particles C (IX) containing no electrolyte) 2. The rotation speed (speed) of the shear blade of the disperser in (b) of the initial emulsification (shearing / dispersion I) is set to 5000 to 10000 rpm / s, and the operations of (a) to (e) are repeated once, and 3 .. The fluid was operated in the same manner as in Preparation Example 7 except that the dispersion conditions (rotation speed (speed) of the shear blades of the disperser) in the pre-curing (hardener addition I + dispersion II) were set to 5000 to 10000 rpm / s. 9 (fluid containing particles C (IX) containing no electrolyte) was obtained.

The average particle size of the particles in the fluid 9 measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3000II, manufactured by Microtrack Co., Ltd.) was 6.5 μm. Further, when the amount of ions of the particles in the fluid 9 was measured by ICP-MS (inductively coupled plasma mass spectrometry) measurement, the amount of lithium ions was 0 ppm and the amount of zinc ions was 0 ppm (total 0 ppm).

Example 1
The fluid 1 prepared in Preparation Example 1 and the fluid 6 prepared in Preparation Example 6 were mixed at a mass ratio of fluid 1: fluid 6 = 90:10 to produce an electrorheological fluid.

Example 2
The fluid 1 prepared in Preparation Example 1, the fluid 6 prepared in Preparation Example 6, and the fluid 8 prepared in Preparation Example 8 are mixed at a mass ratio of fluid 1: fluid 6: fluid 8 = 70: 10: 20. Then, an electrorheological fluid was produced.

Test Example 1
The maximum shear stress (Pa) at 30 ° C. in the fluids A to D shown below and the current density (μA / cm ² ) when a voltage of 3 kV / mm was applied were measured under the following measurement conditions and shown in FIG. ..
A: Fluid 8
B: Electrorheological fluid of Example 1 C: Fluid 1
D: Electrorheological fluid of Example 2 ・ Measurement condition device: Rheometer MCR302 manufactured by Antonio Par
Jig: cc28 (cylinder type, gap 0.3 mm)
Temperature: 30 ° C
Measurement program: (Lab CTI) 12000 to 1s-1

As is clear from FIG. 2, B and D exhibited excellent characteristics of high maximum shear stress and low current density.
On the other hand, A had a high maximum shear stress but a high current density, and C had a low current density but a low maximum shear stress.

Claims (4)

An electrorheological fluid in which polarized particles are dispersed in an electrically insulating medium, wherein the electrically insulating medium contains at least one kind of electrolyte dissolved or dispersed, and the polarized particles contain the electrolyte in the particles. However, the polarized particles include two or more kinds of particles having different concentrations of the electrolyte contained in the particles, and the polarized particles have different average particle diameters represented by the following A to C. An electrorheological fluid consisting of one or more particles.
A: 0.50 to 2.50 μm
B: 3.00 to 5.00 μm
C: 5.50-15.00 μm The polarized particles are composed of two or more kinds of particles having different average particle diameters represented by the above A to C, and the particles having two or more kinds of different average particle diameters are particles due to the difference in the average particle diameters. The electrorheological fluid according to claim 1, wherein the concentrations of the electrolytes contained therein are different from each other. The polarized particles include particles having an average particle diameter indicated by C, and the concentration of the electrolyte contained in the particles having an average particle diameter indicated by C is higher than that of particles having another average particle diameter. The electrorheological fluid according to claim 1 or 2, which also increases. An electrorheological fluid which is a mixture of two or more kinds of electrorheological fluids according to any one of claims 1 to 3.