Claims
- 1. An electrorheological fluid composition comprising dielectric particles as a disperse-phase and an electrically insulating oil as a dispersion medium,
- wherein said dielectric particles have an average particle diameter in a range of 0.001-0.5 .mu.m and a polymer portion and an electrically conductive carbon black portion, said polymer portion including a main chain obtained by polymerizing a vinyl monomer and a silicone containing component and being grafted on said carbon black portion,
- wherein said polymer portion has an affinity to said dispersion medium and a ratio of said polymer portion to said electrically conductive carbon black portion is in a range of 10-3,000 parts by weight to 100 parts by weight; and
- wherein said silicone containing component has a polysiloxane containing structure unit represented by the formula: ##STR6## wherein, A is --COO--, R.sup.1 is hydrogen atom or methyl group, R.sup.2 is an alkylene group having from 1 to 6 carbon atoms, R.sup.3-R.sup.13 are independently an aryl group, an alkyl group having from 1 to 6 carbon atoms or an alkoxy group having from 1 to 10 carbon atoms, a is a natural number, b and c are independently 0 or integers selected from 1-10, and d is 0 or an integer selected from 1-200.
- 2. The electrorheological fluid composition as set forth in claim 1, wherein said carbon black shows a pH below 6.
- 3. An electrorheological fluid composition comprising dielectric particles as a disperse-phase and an electrically insulating oil as a dispersion medium, the dielectric particle having a polymer portion and an electrically conductive carbon black portion;
- wherein (i) said carbon black has a pH of below 6; and (ii) said polymer portion has a carbon--carbon bond in a main chain, and includes a silicone containing component and is grafted to said carbon black by an addition reaction; and
- wherein said silicone containing component has a polysiloxane containing structure unit represent by the formula: ##STR7## wherein A is --COO--, R.sup.1 is hydrogen atom or methyl group, R.sup.2 is an alkylene group having from 1 to 6 carbon atoms, R.sup.3 -R.sup.13 are independently an aryl group, an alkyl group having from 1 to 6 carbon atoms or an alkoxy group having from 1 to 10 carbon atoms, a is a natural number, b and c are independently 0 or integers selected from 1-10, and d is 0 or an integer selected from 1-200.
- 4. The electrorheological fluid composition as set forth in claim 1 or 3
- wherein said electrically insulating oil is a silicone containing insulating oil.
- 5. The electrorheological fluid composition as set forth in claim 1 or 3,
- wherein a carbon content in said carbon black portion is equal to or above 85% by weight.
- 6. The electrorheological fluid composition as set forth in claim 1 or 3,
- wherein said carbon black has a carboxyl group.
- 7. The electrorheolosical fluid composition as set forth in claim 1 or 3, wherein the ratio of the dielectric particles to the electrically insulating oil is 100 parts by weight to 100-2000 parts by weight.
- 8. The electrorheolotical fluid composition as set forth in claim 1 or 3, wherein said silicone containing component is in a side chain of the polymer portion.
Priority Claims (1)
Number |
Date |
Country |
Kind |
5-315124 |
Dec 1993 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 08/356,560, filed Dec. 15, 1994, now abandoned.
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Continuations (1)
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Number |
Date |
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Parent |
356560 |
Dec 1994 |
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