Fluorescent particles, method for preparing the same and paper preventing forgery using the fluorescent particle

Abstract

Fluorescent particles strongly fluorescing upon irradiation with ultraviolet rays, as well as a process for producing the same, are provided. A water-insoluble fluorescent dyestuff and/or pigment fluorescing upon irradiation with ultraviolet rays and a powdery material including starch, cellulose, other polysaccharides and sugars are mixed and granulated. The surface of granules of the powdery material may be coated with the fluorescent dyestuff and/or pigment. In granulation or coating, a resin having reactive groups reacting with the hydroxyl groups of the powdery material is used in combination, whereby particles excellent in water resistance can be obtained. Further, the interaction between an anionic binder contained in the granules and a cationic material contained in the coating layer or between a cationic binder contained in the granules and an anionic material contained in the coating layer can be utilized to confer water resistance on the particles. By inclusion of the fluorescent particles in paper, there can be provided anti-falsification paper wherein the particles fluorescing in a specific hue can be clearly visually recognized upon irradiation with ultraviolet rays.

Dependencies are inferred from the claim text.