| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ink composition which can indicate the duration of time of heat history under constant temperature conditions, can form a clear image, and has a detection term capable of being controlled not by the help of a colorant and a color developer. SOLUTION: There is provided an ink composition containing an electron- donating compound, an electron-accepting compound, a solvent, and a silicone oil and having a oil-soluble resin exhibiting an acid value. The oil-soluble resin exhibiting an acid value comprises an oil-soluble resin having an acid value of 40 or below and an oil-soluble resin having an acid value of 40 or above and is selected among, for example, acrylic resins, phenolic resins, and rosin resins. The oil-soluble resin exhibiting an acid value is contained in an amount of 0.2-50 wt.%. |
