MAGNETIC GRANULAR MATERIAL, PAPER FOR PREVENTING FORGERY USING THE SAME, AND ANTI-FORGERY PRINTED MATTER

摘要

PROBLEM TO BE SOLVED: To obtain an anti-forgery paper suitable for a readily visually determinable anti-forgery printed matter by internally adding a magnetic granular material prepared by fixing a magnetic powder onto the surface of grains capable of manifesting the autohesion properties by physical or chemical actions according to an impact method in a high-speed air stream into a stock. SOLUTION: This magnetic granular material is obtained by fixing a magnetic powder having 0.1-100μm average particle diameter such as tri-iron tetroxide or magnetite onto the surfaces of grains capable of manifesting autohesion properties by physical actions and having 50μm to 2 mm average grain diameter, e.g. true spherical polyethylene grains or grains capable of manifesting the autohesion properties by chemical actions and having 50μm to 2 mm average grain diameter in a papermaking process according to an impact method in a high-speed air stream. An anti-forgery paper prepared by internally adding and fixing the resultant magnetic granular material onto a layer other than the outermost layer composed of three or more paper layers is subjected to a prescribed printing to afford an anti-forgery printed matter.