Patent ID: 6096235
Filing Date: 2000-08-01
Classification: C10M

Abstract:
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; andwherein 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.