| abstract |
[PROBLEMS] To make invisible information easily visible by rubbing with a nail even though the invisible information printed portion is difficult to be colored by rubbing during normal handling, and has high color density and is shaved when visualizing invisible information. Provided are a scratch coloring ink and an invisible information printing sheet using the same, in which it is extremely difficult to visually recognize a portion on which invisible information has been printed without generation of scratch without causing any residue. [Solution] Scratch color developing ink comprising an electron donating dye precursor, an electron accepting compound, and a varnish, and having an average particle size of an internal solid particle component of 0.3 to 25 μm and invisible by the scratch color developing ink An invisible information printing sheet, wherein information is printed on a support. [Selection figure] None |