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
2026-11-04 06:40
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.
References Cited (Backward Citations)
US4033892A
Cited
US4129513A
Cited
US4116857A
Cited
US4183900A
Cited
US4243555A
Cited
US4326961A
Cited
US4392979A
Cited
US4502973A
Cited
US4483788A
Cited
US4687589A
Cited
US4668417A
Cited
EP0207811A2
Cited
US4664843A
Cited
US4790954A
Cited
US4702855A
Cited
US4744914A
Cited
US4812251A
Cited
US4772407A
Cited
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