PURPOSE: To obtain a marking compsn. generating no background fog, developing a sharp black color and excellent in fastness by compounding a specific leuco dye and a developer with an ultraviolet curable resin.
CONSTITUTION: 5-50wt.% of a leuco dye represented by formula I (wherein R1 and R2 are a methyl group or an ethyl group, X is fluorine or chlorine and n is an integer of 0-2) and a developer are mixed with an ultraviolet curable resin using a three-roll stirring device to prepare a marking compsn. As a suitable example of the ultraviolet curable resin, there is a radical or cation polymerization type resin. As a concrete example of the leuco dye represented by the formula I, there are 3-diethylamino-7-0-fluoroanilinofluorane, 3- diethylamino-7-p-fluoroanilinofluorane and the like. As a concrete example of the developer, there are 4,4'-sufonyldiphenol, bis-(3-allyl-4-hydroxypheyl) and the like.
KUDO MASARU
NIIMOTO HARUKI
