Process for producing pigment-coated phosphors

摘要

A pigment-coated phosphor having good finish sieve passability and capable of forming a fluorescent film with excellent properties can be produced from a process characterized by: (1) the first step of adding to a water suspension of a phosphor and a pigment an anionic polymer emulsion which has a minimum film forming temperature of less than 30 DEG C.; (2) the second step of adding a cationic polymer emulsion which has a minimum film forming temperature of 30 DEG C. or lower; (3) the thrid step of adding an anionic polymer emulsion which has a minimum film forming temperature of 30 DEG C. or higher; and (4) the fourth step of making the mixture system neutral or weakly acidic.