Abstract: An infrared fluorescent particles emitting fluorescence upon irradiation with infrared rays, and anti-falsification paper in which the particles are contained and the particles emitting fluorescence at a specific hue can be clearly recognized visually upon irradiation with infrared rays are provided. The infrared fluorescent particles comprise granules of a powdery material and a coating layer of a water-insoluble infrared fluorescent pigment emitting fluorescence upon irradiation with infrared rays formed on the surface of the granule. Water resistance can be imparted to the particles by using a resin having reactive groups capable of reacting with hydroxyl groups of the powdery material in combination as a binder upon coating, or by incorporating an anionic binder or a cationic binder in the granules and incorporating a cationic material or an anionic material in the coating layer.

Abstract: Anti-falsification paper characterized in that thin fragments having brightness, which are obtained by fragmenting nacreous pigment coated paper coated with a nacreous pigment coating solution mainly comprising a nacreous pigment and a binder insoluble in cold water but soluble in hot water, are allowed to exist near the surface of a substrate sheet. Even when falsification is attempted by reproduction using a color copying machine, the colors of the thin fragments having brightness, which are mixed in paper, cannot be reproduced. Therefore, a genuine (original) can be easily distinguished from a forgery (copy). The thin fragments are firmly bonded to paper by the action of the binder, and fall-off of the thin fragments does not occur at the time of printing. Even when anti-falsification paper becomes spoilage or waste paper, thin fragment with brightness does not adversely affect recovery of the pulp.