Electrophoretic particle, process for its production, and its use

A process for producing an electrophoretic particle, comprising steps of:

• carrying out radical polymerization using a polymerization initiator in a state where a pigment particle and monomer components are present in a solvent to give an electrophoretic particle comprising a pigment particle and a polymer layer formed on a surface of the pigment particle, wherein:
• the pigment particle is a pigment particle having an average particle diameter of 1 μm or smaller which has been mixed with a coupling agent having a polymerizable reactive group prior to the radical polymerization;
• an amount of the coupling agent having a polymerizable reactive group to be used is 0.1% to 5% by weight, based on an amount of the pigment particle to be used;
• the solvent comprises a hydrophilic organic solvent and water, and a ratio of the water to be added is 10% to 30% by weight, based on a total amount of the solvent;
• the monomer components comprise a hydrophilic monomer and a hydrophobic monomer, and a ratio of the hydrophilic monomer to be added is 5% to 30% by weight, based on a total amount of the monomer components;
• and
• the polymerization initiator is water soluble, and a concentration of the monomer components is 0.5% to 5% by weight, based on a total amount of the solvent and the monomer components.