Magnetorheological fluids and polymer coated magnetic particles

摘要

Magneto-rheological fluid consists of magnetisable particles of an oleophilic fluid and optionally a thickener. The magnetisable particles are coated with an organic polymer. Also claimed is the production of the magnetisable particles coated with polymer comprising silanizing the particles by reacting with a silane of formula: R1-Si((R2)a)(X2)3a (where R1 = 1-20C alkyl or 2-20C alkylene optionally substituted wit an amino, isocyanate, methacryloxy, acryloyloxy, epoxy or mercapto group and/or interrupted by O, NH, COO or NHCOO; R2 = phenyl, or 1-6C alkyl; X = hydrolysable group; and a = 0-2).