Disclosed is a red luminous ink composition comprising a europium complex represented by the formula:
wherein R1 is a hydrogen atom or a substituent selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms and a halogen atom, R is a group selected from the group consisting of a fluorine-comprising alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted alkyl group having from 1 to 6 carbon atoms, a substituted or unsubstituted aralkyl group having from 7 to 10 carbon atoms and a substituted or unsubstituted aryl group having from 6 to 12 carbon atoms. The red luminous ink composition exhibits satisfactory emission intensity under ultraviolet irradiation.
The present invention relates to an red luminescent ink composition exhibiting adequate and stable emission intensity under irradiation of ultraviolet rays and high solubility for a resin and an organic solvent. The ink composition of the present invention contains a luminous compound represented by the following formula (1):
wherein R is a perfluoroalkyl group having 2 to 20 carbons, L
1
and L
2
are the same or different and are sulfoxide having a substituted or unsubstituted aryl group or a substituted or unsubstituted an alkyl group.