| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an ink composition for invisible recognition capable of giving a concealed indication invisible under visible rays which cannot easily be recognized by many and unspecified persons, and further without causing wear of a printing heater element when the printing paper of a heat-sensitive paper type having a concealed indication printed thereon is printed. SOLUTION: The ink composition for invisible recognition comprises a binder component and at least one laser dye selected from the group consisting of 1,3,3,1',3',3'-hexamethylindo-carbocyanine iodide and 5,5'-dichloro-11- diphenylamino-3,3-diethyl-10,12-ethylene-thiatricarbocyanine perchlorate and has a viscosity of >=200 mP.s.</p> |
