| abstract |
(57) [Abstract] [Purpose] To provide an electrorheological fluid that generates large shear stress and is excellent in current characteristics and stability over time. [Structure] An electrorheological fluid obtained by dispersing particles of a sulfonated polymer obtained by sulfonation of a copolymer of a vinyl aromatic compound and a polyvinyl compound in an insulating liquid. In the polymerization reaction, the polymerization rate is 30. Polymerization is carried out at a temperature of less than 80 ° C. until reaching a range of from 80% by weight to less than 80% by weight, and then the polymerization rate is 99.8% by weight. An electrorheological fluid composition characterized in that polymerization is carried out at a temperature of 80 ° C. or higher until the above temperature is reached. [Effect] A large shear stress is generated and an electrorheological fluid with excellent current characteristics and stability over time can be obtained. Clutch, damper, brake, shock absorber, actuator, valve, engine mount. It can be applied to various devices such as. |