(1). Irreversible temperature sensitive ink

Irreversible temperature sensitive ink includes coloration ink and discoloration ink. Irreversible coloration temperature sensitive ink is colorless in appearance but shows colors after being heated and can’t restore colorless once again after cooling off. The original color of Irreversible discoloration temperature sensitive ink can be changed into another one and it can’t restore its original colors after being cooled once again.

(2). Reversible temperature sensitive ink

Reversible temperature sensitive ink includes three kinds: coloration, fading and discoloration ones. Reversible coloration temperature sensitive ink is colorless in appearance but shows colors after being heated and can restore colorless after being cooled. The original color of reversible fading temperature sensitive ink disappears after being heated and it can restore its original color after being cooled. The original color of reversible discoloration temperature sensitive ink can be changed into another one and it can restore its original color after being cooled.