JPH02196892A - Fluid responding to electric field - Google Patents

Abstract

PURPOSE:To obtain the subject fluid having suppressed loss of long-term stability caused by the presence of water and improved resistance to the dissolution of metallic part with electric field by mixing a disperse phase consisting of fine powder into a specific fluoroalkoxyphosphonitrate (or a continuous liquid phase composed mainly thereof). CONSTITUTION:The objective fluid is produced by mixing (A) a continuous liquid phase composed (mainly) of a fluoroalkoxyphosphonitrate of formula (m is 1.3-2.8; n is 3-5.3; h, k and l are 0-2n; h+k+l=2n) with (B) a disperse phase consisting of fine powder of preferably TiO2, K2Ti6O13 or BaTiO2. The fluid is useful as a material for a compact and easily temperature-controllable electro-mechanical actuator such as shock absorber, clutch and valve having improved lowering of the temperature dependency of the response characteristics to electric field.

Description

[Detailed description of the invention] (Industrial application field) FIELD OF THE INVENTION This invention relates to electroresponsive fluids.

(Prior Art) US Patent No. 141 by Winslow
No. 7850/111M discloses that certain suspensions of finely divided solids, such as starch, lime or derivatives thereof, gypsum, flour, gelatin, etc., are dispersed in non-conductive liquids, such as olive oil or mineral oil. Techniques have been disclosed to increase the flow resistance if a potential difference is applied to the suspension. This effect is commonly referred to as the low effect.

The increase in flow resistance due to the application of an electric field was initially interpreted as an increase in viscosity, and materials exhibiting this effect were called electrorheological fluids. However, subsequent studies have shown that the increase in flow resistance is not due solely to an increase in viscosity, as in Newtonian fluids, but is due to Bingham plasticity induced by an applied electric field.
sticity) l, and it was found that I! ! & Suspended liquids are now called electroresponsive fluids. Research to improve both the dispersed and continuous phases of electroresponsive fluids has already been published in British patent tjS150163.
No. 5, same! No. 81570234, UK Patent Application No. 210
No. 0740A, No. 2119392A and fi21
No. 53372A, etc. However, even in these methods, the mechanism by which the electric field response phenomenon occurs has not been fully elucidated, and therefore they have not been put to practical use.

Many of the electroresponsive fluids that have been proposed so far contain a small amount of water, which is thought to be primarily bound to the dispersed phase, and when dried rigorously, the fluids can exhibit sufficient electroresponsive phenomena. However, the presence of this water causes problems such as corrosion of the device, limitations on operating temperature, current leakage, and decreased temperature dependence of response characteristics. Furthermore, another problem with electroresponsive fluids is that they are a suspended dispersion system of solid and liquid phases. That is, it is difficult to maintain a uniformly mixed state of two different phases over a period of time.

The inventors of the present invention have conducted extensive studies in view of the above-mentioned problem α that hinders practical application. ! ! It was realized that the liquid continuous phase of the field-responsive fluid occupies an important part. and,
It was determined that this issue could be resolved by addressing the following points. That is, the liquid continuous phase 1 has a high boiling point, a low freezing point, and a low vapor pressure at standard operating temperatures that can maintain the properties of an electroactive fluid over a wide range of temperatures (ideally from -40°C to 150°C). , 2. It contains a larger amount of in-phase, has a low viscosity that can enhance the Winslow effect, and has high electrical resistance and dielectric strength that allows it to conduct little current and can be used over a wide range of electric field strengths. , 4. In order to prevent precipitation of the suspended solid phase, it has a density close to that of the solid phase (usually, the surface image is high density), but it is mixed with other substances that can adjust the density. 5. is a material that is chemically stable under the conditions of use and storage despite the presence of many potential catalytic surfaces provided by particles in the fluid; 6 7. Any substance may be used as long as it has no li property and does not accumulate or remain in nature;

(Problems to be Solved by the Invention) An object of the present invention is to provide an electric field responsive fluid that satisfies the above points and exhibits high electric field responsiveness.

(Means for Solving the Problems) The present invention provides a liquid continuous phase mainly consisting of fluoroalkoxyphosphonitrite, which is a substance represented by the following general formula (1) or a mixture thereof, and a finely powdered substance. It relates to an electroresponsive fluid formed by mixing a dispersed phase.

1 (H(CF*CP,)+aCHtO)h (CF,
CB,0)k(CF,CFaCIl,O)1(P
N) nl [However, in the formula, the segment represented by (CF 2 CF 2) @ is a single segment that is an integral multiple of the unit (CF 2 CF z) or a mixture of segments with different chain lengths that are an integral multiple of the unit. In the case of a single segment, -=2, and in the case of a mixture of segments with different chain lengths, the square represents the average a of the (CF 2CF z) unit. It means the average number of repeats, the value of - is in the range of 1.3≦so≦2.8, and n indicates the number of repeats of the PN unit of the phosphonitrile ring skeleton, and the value of - is in the range of 1.3≦so≦2.8. For mixtures,
It indicates the average number of repetitions, and takes a real value within the range of 3≦n≦5.3, and the values of h, k, and l are each 2.
1≧h≧0.2n≧ and ≧0.2n≧l≧0, and h+ satisfies +Z=2n. ] The compound of formula (1) is a substance produced according to the method described in JP-A-62-265394, and for example, as shown in the reference examples below, it is a compound of phosphonitrile halide oligomer and fluorinated It is a substance produced from alcohol. Examples of the phosphonitrile halide oligomer include phosphonitrile chloride trimers, phosphonitrile chloride tetramers, and mixtures thereof. Examples of fluoroalcohols include 1.1. Examples include ω-trihydroperfluoroalcohol and mixtures thereof with 2*L, 3,3-3-pentafluoropropanol. Further, the fluoroalkoxyphosphonitrilate of the above formula (1) can be used as the fluoroalkoxyphosphonitrite of the above formula (1).
A mixture of one or more ω-trihydroperfluoroalcohols and 2,2,3,3,3-pentafluoropropyl is reacted with sodium or the like to form an alcoholade, and then this alcoholade is converted into a phosphor. It is also produced by reacting with oligomers of nitrile halides.

Representative physical properties of the series of compounds of formula (1) are shown in Table 1 and Figures 1 and 2. These values indicate that the compounds of the present invention have boiling points higher than the upper limit of the desired temperature range;
It has a freezing point of -40°C or lower, and its vapor pressure at 50°C is as low as 10-S to 10-')-rel. In addition, it has low viscosity (60 centistokes or less at 50°C) and high density (
Specific gravity at 15℃ is about 1.8), concentrated sulfuric acid, concentrated nitric acid Ffl? Oxidation by concentrated mineral acids of P, strong Lewis acids such as aluminum chloride, strong alkalis such as potassium hydroxide and sodium chloride, and under high temperature oxygen and on the surface of active metals such as aluminum.
It is stable against reduction and has excellent chemical safety against catalysts. Furthermore, safety has been confirmed as it is non-toxic to male rats and red moths, and is negative for both variable and M product, and various solvents such as benzene, ether, ketone, and ester. Since it is soluble in water, it can be easily washed and removed. - The compatibility of the strength wood invention compound is not limited to only solvents, but is also compatible with chlorofluoro oils, ester oils, etc., which is a very convenient feature for viscosity adjustment, density adjustment, and addition of various additives. ing.

Incidentally, the substantially anhydrous state described in the present invention refers to a specific or each dispersed phase in which the dispersed phase is 0%. lmm
The continuous phase was dried at 100° C. for 2 days under a vacuum of Hg or less to give a constant weight, and the continuous phase was optionally treated with synthetic zeolite heated and dried at 400° C.

As the dispersed phase that can be used in the present invention, inorganic fine powders such as silica sol, synthetic zeolite, zinc oxide, titanium dioxide, alumina, potassium titanate, and barium titanate can be used alone or in combination. These dispersed phases can be used at any ratio within the range of 1 so that the mixed composition with the continuous phase has the desired fluidity in the target temperature range, but the preferred ratio is such that the volume ratio of the dispersed phase is 011 to 50%, more preferably 1 to 40%.

In the present invention, a liquid continuous phase in which a substance compatible with the fluoroalkoxyphosphonitrite of formula (1) is added can also be used. Examples of the compatible substances include ester oils such as 2-ethylhexanol sebacate, halocarbon oils such as chlorofluorocarbons, and the like.

Regarding the fact that the fluid containing the compound of the present invention as a liquid continuous phase exhibits remarkable electric field response behavior in a qualitatively anhydrous system,
Although the details are unknown, it is thought that the appropriate dielectric constant and unique skeletal structure of the compound of the present invention are at play.

(Effects of the Invention) The electro-responsive fluid of the present invention suffers from the presence of water, which was the biggest drawback of conventional fluids! Shock 7 punch bars, clutches, and pulps are compact and easily electrically controllable, eliminating problems such as poor stability during storage, elution of electrodes and other metal parts due to the application of an electric field, and poor temperature-dependent performance of electric field response characteristics. This makes it possible to realize electro-mechanical actuators such as

The evaluation of the electric field response characteristics in the present invention was conducted using a cylindrical type with an inner diameter of 22.85 seconds and having concentric rings as shown in FIG. 4
The gap between the pole and the a-ter electrode with an outer diameter of 18.85 m (
The test was carried out by measuring the change in viscosity when a predetermined direct current voltage was applied between three test samples (2 mm) and a sample fluid.

(Examples) The present invention will be described in detail below with reference examples and examples, but the present invention is not limited to these.

Reference example 1 (Production example 1 of JP-A-62-265:194)
2.2,3.3.3-pentafluoropropyl/- in a Nishitsuro flask equipped with a condenser, stirrer and thermometer.
(310 g (2,06 moles) of 1,1.5-trihydroperfluoropentanol and 2,000 g of toluene were added and cooled). and gradually raise the temperature,
The reaction was carried out at 40°C until the sodium was completely dissolved. A solution of 178 g (0,384 mol) of phosphonitrile chloride tetramer dissolved in 1,000 liters of toluene was added dropwise to this reaction solution at about 50° C., and the reaction was carried out under reflux for 4 hours. Wash with water to remove the generated tetratum chloride.
After dehydration and concentration, 620 g of an oily crude product was obtained. After simple distillation of this at 160-220℃10.5-0.03-1g, high temperature M density 5>fNH@11 P-900
01'3 (Shibata Chemical 91) 1. The mixture was subjected to rectification fractionation, and each fraction was analyzed by chromatography, infrared absorption spectroscopy, and proton nuclear magnetic resonance spectroscopy to confirm the formation of the compounds shown below.

(CF3CF2CH20)/(IICF, CF, CF,
CF, CI (20), JP, N.

Example 1 0.05 mm) (g, anatase η! titanium dioxide powder vacuum dried at 100°C for 48 hours (average particle size 0.3 μm)
) 30 parts by volume was dehydrated with synthetic zeolite heated and dried at 400°C.
(II(CF, CF2)2C1,O) 3 (CF,
CF, Cl2O) 3 (PH), l) was added to 70 volume parts and degassed and mixed at 100° C. and 0.5-10 g for 2 hours. The viscosity of the fluid thus prepared was 9 at 30°C.
0 centipoise, and had good fluidity at room temperature. This fluid is transferred between a cylindrical external electrode with an inner diameter of 22.85 mm having the same central axis as shown in FIG.
It was sealed in a gap 2II11 m between internal rotor electrodes of 8.85 mm, and while applying a direct current voltage of 0 to 100 OV in steps, the change in viscosity was directly read and recorded using a viscometer. Although the response speed could not be accurately measured with this viscometer, it was on the order of seconds or less.

The electric field response behavior of this fluid at 30°C is shown in Fig. 4-■ as a magnification of viscosity change.

Example 2 Potassium titanate (K 2T
iao 13: TTS M O-N, human urine chemistry (
Co., Ltd. 91) 33 parts by volume and Phos 7, Flor NF-4
6 (67 parts by volume) in the same manner and the fluid i1! Made by I. This composition has a diameter of about 100 centivoids at 30°C;
In the same manner as in Example 1, the viscosity change due to DC step application was measured. The measurement results at 30°C are based on the viscosity of the applied voltage Ov, and the increase ratio is also shown in Fig. 4-■. These results show a 6 to 10 times increase in viscosity at 500 V/m-, and no hysteresis was observed, indicating a good electric field response.
! I! Has IJ and is it good? It is an lt-field responsive fluid.

Example 3 Barium titanate powder (
r3aTiot: W±titanae! N-2203 manufactured by Co., Ltd.
25 parts by volume and Phos 7 Allol NF-100 (+(H(C
F2CF2), CII□O), (r'N), 1 manufactured by Otsuka Chemical Co., Ltd.] All 75 volumes were mixed in the same manner as in Example 1, and the electric field response was measured. The results are shown in Figure 5-■. .

Example 4 Similar to Example 3, BaTi0. and I CIt(CF2C
F2)2CI+20), (CF3CF2CH20)
The results for the fluid prepared using -(PH)d are shown in Figure 5-■.

Example 5 Implementation (Similar to !13, K z T i 60° and I (
CFtCFzCIhO) s (CF=CII□01.
Figure 5 shows the results of the fluid prepared using (PH)31.
Shown below.

Example 6 A 1:1 mixture of Phos770-L NF-46 and 2-ethylhexanol sebacate was used as the liquid continuous phase.
Shown in Figure-■.

Table 1 t (It(CF, CF2) mcll, o) h
(CF, C1l, 0) k (CF, CF2Cl+,
0) l (PN) n■ Fig. 1 Fig. 2rlJ Temperature f℃) 4. Fig. (1) Viscosity-temperature diagram,
The m3 diagram is a schematic diagram of the viscosity measurement system for electroresponsive fluids.
FIGS. 4 and 5 are graphs showing the relationship between the applied voltage and the viscosity increase rate of the electro-responsive fluid of the example.

(that's all) Applicant: Otsuka Chemical Co., Ltd. Representative Patent Attorney 1) Iwao Mura Viscometer Figure 5 Applied voltage (V/mm)

Claims (4)

[Claims] (1) An electric field response obtained by mixing a fine powder dispersed phase with a fluoroalkoxyphosphonitrilate, which is a substance represented by the following general formula (1) or a mixture thereof, or a liquid continuous phase mainly composed of the same. Sexual fluid. {[H(CF_2CF_2)mCH_2O]h[CF_
3CH_2O]k[CF_3CF_2CH_2O]l[
PN]n}(1) [However, in the formula, (CF_2CF_2)
The segment indicated by m indicates a single segment that is an integral multiple of the unit (CF_2CF_2) or a mixture of segments of different chain lengths that are integral multiples, and in the case of a single segment, m = 2. , and when segments with different chain lengths coexist, m means the average number of repetitions of (CF_2CF_2) units representing the average chain length, and the value of m is 1.3≦m. ≦2.8, and n indicates the number of repeats of the PN unit of the phosphonitrile ring skeleton, and in the case of a mixture of rings with different repeat numbers, indicates the average number of repeats, 3 ≦n≦5.3
The values of h, k, and l are in the ranges of 2n≧h≧0, 2n≧k≧0, and 2n≧l≧0, respectively, and satisfy h+k+l=2n. ] (2) The electroresponsive fluid according to claim 1, which uses a liquid continuous phase to which a substance compatible with the fluoroalkoxyphosphonitrite described in claim 1 is added. (3) The electro-responsive fluid according to claim 1 or 2, which exhibits electro-responsive properties in a substantially anhydrous state. (4) Fine powder dispersed phase is TiO_2, K_2Ti_6O
Claims 1 to 3 are either _1_3 or BaTiO_3.
3. The electroresponsive fluid according to any one of 3.