NON-CHARGEABLE COLORED RESIN PARTICLE AND USE OF THE SAME

摘要

PROBLEM TO BE SOLVED: To provide non-chargeable colored resin particles excellent in dispersion stability in a dispersion medium, and use of the particles.SOLUTION: The non-chargeable colored resin particles include: pigment particles comprising a metal oxide treated with a surface treating agent; and a polymer coating surfaces of the pigment particles. The polymer includes a structural unit derived from a reactive dispersant and a structural unit derived from an aromatic vinyl monomer having no poplar group. The reactive dispersant comprises a copolymer of a monomer mixture including 100 parts by weight of a silicone macromonomer and 0.5 to 20 parts by weight of an asymmetric polyvinyl monomer. When the non-chargeable colored resin particles dispersed by 20 wt.% as a solid content concentration in a silicone oil having a kinetic viscosity of 100 cSt or less are interposed between a pair of planar indium tin oxide electrodes parallel to each other and spaced from each other at a distance of 50 μm and subjected to application of 15 V voltage for 60 seconds, the resin particles exhibit a measured charge amount of 20 nC/cmor less. The non-chargeable colored resin particles can be used for an electrophoretic display device.