Abstract
Core-shell structured microcapsule with 0.44 μm diameter had been prepared by encapsulating the cationic photoinitiator and fluorane dye as photo-sensitive color-forming ingredients. The encapsulation ratio was detected as about 61.6%. The shell was thermal stable below 270 °C. After UV exposure for 20 s, the color-forming image density had been increased from 0.1 to 0.75. Decolorization property had been observed that the higher the temperature was, the more decrement the image density decolorized. The density decayed from 0.74 to 0.23 in just 5 min at 180 °C. It was proposed that the higher temperature influenced the decolorization process through competitive procedures. One procedure was the thermal decomposition of cationic photoinitiator to heighten color image density, and the other was to destroy the carboxy bonds in the color-formed fluorane dyes after thermal energy transmitted through phase-changed microcapsule shell. It was concluded that the latter one played a more significant role under higher temperature above 140 °C, and performed the decolorization property.
