US5032308A
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Layered mixed metal hydroxides in electrorheological fluids
Assignee: Dow Chemical Co
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Filing: 1989-11-07
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Granted: 1991-07-16
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Expires: 2009-11-07
Abstract
Abstract An electrorheological fluid wherein the discrete phase comprises a layered mixed metal hydroxide of the formulae: Li.sub.m D.sub.d T(OH).sub.(m+2d+3+na) A.sub.a.sup.n and Mg.sub.x Al.sub.y (OH).sub.z and the continuous phase is a low dielectric fluid. The layered mixed metal hydroxides may be functionalized with an aliphatic carboxylic acid or with the reaction product of a clay and an amine salt to provide a more dispersible particulate phase. The electrorheological fluids have improved thermal stability and provide a strong response to low electric field strengths while requiring a low concentration of layered mixed metal hydroxide component.
Inventors
- 👤 Thomas M. Knobel
- 👤 Robert A. Cipriano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 04:39
CPC Classifications
C; C10; C10M; C10M171/00; C10M171/001
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
167 words
A method of using an electrorheological fluid comprising: (1) making an electrical contact across an electrorheological fluid comprising: (a) a discrete phase comprising layered mixed metal hydroxide selected from the group consisting of: Li.sub.m D.sub.d T(OH).sub.(m+2d+e+na) a.sub.a.sup.n and Mg.sub.x Al.sub.y (OH).sub.z wherein m is 0 to about 1; D is a divalent metal ion selected from the group consisting of magnesium, calcium, barium, strontium, manganese, iron, cobalt, nickel copper and zinc; d is 0 to about 4; T is a metal ion selected from the group consisting of aluminum, gallium, chromium, and iron; A is a monovalent or polyvalent ion other than an hydroxyl ion; n is the valence of the anion A; a is the number of anions A in the formula; (m+2d+3+na) is equal to or greater than 3; x is on average about 1.7; y is on average about 0.5; z is on average about 5; and (b) a low dielectric constant continuous phase; and (2) applying an electrical field across the electrorheological fluid.
Claim 2
Independent Claim
167 words
A method of using an electrorheological fluid comprising: (1) making an electrical contact across an electrorheological fluid comprising: (a) a discrete phase comprising layered mixed metal hydroxide selected from the group consisting of: Li.sub.m D.sub.d T(OH).sub.(m+2d+e+na) a.sub.a.sup.n and Mg.sub.x Al.sub.y (OH).sub.z wherein m is 0 to about 1; D is a divalent metal ion selected from the group consisting of magnesium, calcium, barium, strontium, manganese, iron, cobalt, nickel copper and zinc; d is 0 to about 4; T is a metal ion selected from the group consisting of aluminum, gallium, chromium, and iron; A is a monovalent or polyvalent ion other than an hydroxyl ion; n is the valence of the anion A; a is the number of anions A in the formula; (m+2d+3+na) is equal to or greater than 3; x is on average about 1.7; y is on average about 0.5; z is on average about 5; and (b) a low dielectric constant continuous phase; and (2) applying an electrical field across the electrorheological fluid.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein said layered mixed metal hydroxide is Mg 1 ·7 Al 0 ·5 (OH) 5 .
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein said continuous phase is mineral oil or silicone-based oil.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein said electrorheological fluid includes an amount of a functionalizer sufficient to disperse the layered mixed metal hydroxide in the continuous phase.
Claim 6
Dependent Claim
13 words
The method of claim 4 wherein said functionalizer is an aliphatic carboxylic acid.
Claim 7
Dependent Claim
31 words
The method of claim 1 wherein the discrete phase comprises a layered mixed metal hydroxide complexed with the reaction product of a negatively charged composition and the salt of an amine.
Claim 8
Dependent Claim
13 words
The method of claim 6 wherein the negatively charged composition is a clay.
Claim 9
Dependent Claim
33 words
The method of claim 1 wherein said low dielectric continuous phase is selected from the group consisting of alcohols, polyols, glycols, hydrocarbons, halogenated hydrocarbons, mineral oil, silicone-based oils and greases, aldehydes and ketones.
Claim 10
Dependent Claim
23 words
The method of claim 7 wherein the layered mixed metal hydroxide is complexed with the reaction product of LAPONITE and an amine salt.
Claim 11
Dependent Claim
26 words
The method of claim 1 wherein the layered mixed metal hydroxide comprises from about 0.05 wt % to about 20 wt % of the electrorheological fluid.
Claim 12
Dependent Claim
26 words
The method of claim 10 wherein the layered mixed metal hydroxide comprises from about 0.05 wt % to about 2.0 wt % of the electrorheological fluid.
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