Preparation of Reversible Thermochromic Ink for Flexography Printing on Paper and Study its Colorimetric Properties

Thermochromic printing inks are used as security inks which respond to the color change upon exposure to different temperatures. these inks with unusual chemical and physical properties are mostly produced for flexographic, screen and rotogravure printing systems under the supervision of skilled technical experts and with precise security controls. since flexographic thermochromic inks can be used easily for smart packaging including different substrates, in this study a thermochromic ink was prepared with an activation temperature of 31 °c for flexographic printing. the dynamic colorimetric properties were studied at 28-45 °c. tc contrast and yellowness of tc sample were calculated during heating and cooling.