Patent ID: 6946168

Claim:
A reversibly thermochromic ultraviolet ray-hardening ink composition, which comprises: (1) a microencapsulated pigment comprising a reversibly thermochromic composition comprising (A) an electron-donating compound, (B) an electron-accepting compound and (C) a color change temperature-controlling agent which controls color reaction generation temperature of the former two compounds; and (D) a light resistance-providing agent represented by formula (1): wherein n=8 to 17, C n H 2n+1 represents a straight or branched alkyl group, X=C 1 to C 4 straight or branched alkyl group or halogen, Y=C 1 to C 4 straight or branched alkyl group or halogen, p=0 to 3, and m=0 to 3, and (2) a photo-polymerizable composition comprising an ultraviolet ray absorbent, a reactive oligomer, a reactive monomer, and an acylphosphine oxide photo-polymerization initiator, wherein said microencapsulated pigment is dispersed in said photo-polymerizable composition.